Itoh, Hiroyuki (Milpitas, CA, US)
Tanemura, Shigeki (Milpitas, CA, US)
Araki, Hironori (Milpitas, CA, US)
Plaque It!
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| 20030058583 | Write head having first pole piece with frequency dependent variable effective throat height | March, 2003 | Lam et al. | 360/317 |
| 20030151850 | Magnetic heads for perpendicular recording and magnetic recording disk apparatus using the same | August, 2003 | Nakamura et al. | 360/125 |
| 20050188530 | Method of manufacturing thin-film magnetic head | September, 2005 | Sasaki et al. | 29/603.01 |
| JP2003203311A | July, 2003 | METHOD FOR FORMING MAGNETIC LAYER PATTERN AND METHOD FOR MANUFACTURING THIN-FILM MAGNETIC HEAD | ||
| JP2003242607A | August, 2003 | PERPENDICULAR RECORDING MAGNETIC HEAD AND MAGNETIC DISK DRIVE ON WHICH THE MAGNETIC HEAD IS MOUNTED |
1. A magnetic head substructure used for manufacturing magnetic heads, each of the magnetic heads comprising: a medium facing surface that faces toward a recording medium; a coil that generates a magnetic field corresponding to data to be written on the recording medium; and a pole layer that incorporates a track width defining portion having an end face located in the medium facing surface, the pole layer allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough and generating a write magnetic field for writing the data on the recording medium, the substructure comprising: a substrate; a plurality of sets of the pole layer and the coil formed in the substrate, such that a plurality of rows of pre-head portions that will be the respective magnetic heads later are aligned; a plurality of indicators each of which serves as a reference for indicating a region in which the medium facing surfaces of the magnetic heads are to be formed; and a plurality of magnetic layers each of which includes: a pole-layer-corresponding portion that will be one of the pole layers; an indicator portion corresponding to one of the indicators; and a coupling portion that couples the pole-layer-corresponding portion and the indicator portion to each other.
2. The substructure according to claim 1, wherein: the end face of the track width defining portion located in the medium facing surface has: a first side close to the substrate; a second side located opposite to the first side; a third side connecting an end of the first side to an end of the second side; and a fourth side connecting the other end of the first side to the other end of the second side; the second side defines a track width; and the end face of the track width defining portion has a width that decreases as a distance from the first side decreases.
3. The substructure according to claim 1, wherein the indicators are provided on both sides of the track width defining portion, the sides being opposed to each other in a direction of width of the defining portion.
4. The substructure according to claim 3, wherein each of the pole layers and the indicators is conductive, and the indicators are electrically connected to the respective pole layers.
5. The substructure according to claim 1, further comprising an encasing layer having grooves that accommodate the pole layers.
6. The substructure according to claim 5, wherein the indicators are located at a height the same as a height at which the pole layers are located.
7. The substructure according to claim 1, further comprising an encasing layer having plurality of grooves that accommodate the plurality of magnetic layers.
8. The substructure according to claim 1, wherein the indicators are made of a layer having conductivity.
9. The substructure according to claim 1, further comprising an encasing layer having grooves that accommodate the pole layers and other grooves that form the indicators.
10. The substructure according to claim 1, wherein each of the indicators have an end that is parallel to the region in which the medium facing surfaces are to be formed, and a location of the end serves as a reference for indicating a location of the region.
11. The substructure according to claim 10, wherein a distance between a location of the reference and the region falls within a range of 0 to 1.0 mm inclusive.
12. The substructure according to claim 1, wherein each of the indicators have two ends that are parallel to the region in which the medium facing surfaces are to be formed, and a location of a middle between the two ends serves as a reference for indicating a location of the region.
13. The substructure according to claim 12, wherein a distance between a location of the reference and the region falls within a range of 0 to 1.0 mm inclusive.
14. The substructure according to claim 1, wherein a distance between the track width defining portion and the indicators taken in a direction of width of the defining portion falls within a range of 0.1 to 5.0 mm inclusive.
15. The substructure according to claim 1, wherein the indicators are located in a region that will not remain in the magnetic heads.
16. The substructure according to claim 1, wherein at least part of each of the indicators is located in a region that will remain in the magnetic heads.
17. The substructure according to claim 16, wherein the part of each of the indicators that remains in the magnetic heads indicates a length of the track width defining portion taken in a direction orthogonal to the medium facing surface.
18. The substructure according to claim 1, wherein the magnetic heads are those used for a perpendicular magnetic recording system.
19. A magnetic head substructure used for manufacturing magnetic heads, each of the magnetic heads comprising: a medium facing surface that faces toward a recording medium; a coil that generates a magnetic field corresponding to data to be written on the recording medium; and a pole layer that incorporates a track width defining portion having an end face located in the medium facing surface, the pole layer allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough and generating a write magnetic field for writing the data on the recording medium, the substructure comprising: a substrate; a plurality of sets of the pole layer and the coil formed in the substrate, such that a plurality of rows of pre-head portions that will be the respective magnetic heads later are aligned; and a plurality of indicators each of which serves as a reference for indicating a region in which the medium facing surfaces of the magnetic heads are to be formed, wherein: at least part of each of the indicators is located in a region that will remain in the magnetic heads; and the part of each of the indicators that remains in the magnetic heads indicates a length of the track width defining portion taken in a direction orthogonal to the medium facing surface.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of manufacturing magnetic heads used for writing data on a recording medium and to a magnetic head substructure used for manufacturing magnetic heads.
2. Description of the Related Art
The recording systems of magnetic read/write devices include a longitudinal magnetic recording system wherein signals are magnetized in the direction along the surface of the recording medium (the longitudinal direction) and a perpendicular magnetic recording system wherein signals are magnetized in the direction perpendicular to the surface of the recording medium. It is known that the perpendicular magnetic recording system is harder to be affected by thermal fluctuation of the recording medium and capable of implementing higher linear recording density, compared with the longitudinal magnetic recording system.
In each of the longitudinal magnetic recording system and the perpendicular magnetic recording system, magnetic heads typically used have a structure in which a reproducing (read) head having a magnetoresistive element (that may be hereinafter called an MR element) for reading and a recording (write) head having an induction-type electromagnetic transducer for writing are stacked on a substrate.
In each of the longitudinal and perpendicular magnetic recording systems, the write head comprises a coil for generating a magnetic field corresponding to data to be written on a recording medium, and a magnetic pole layer for allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough and generating a write magnetic field for writing the data on the recording medium. The pole layer incorporates a track width defining portion and a wide portion, for example. The track width defining portion has an end located in a medium facing surface that faces toward the recording medium. The wide portion is coupled to the other end of the track width defining portion and has a width greater than the width of the track width defining portion. The track width defining portion has a nearly uniform width.
To achieve higher recording density, it is a reduction in track width, that is, a reduction in width of the end face of the pole layer taken in the medium facing surface, and an improvement in writing characteristics that is required for the write head. An improvement in writing characteristics is, for example, an improvement in overwrite property that is a parameter indicating an overwriting capability. The overwrite property is reduced if the track width is reduced. It is therefore required to achieve a better overwrite property as the track width is reduced. Here, the length of the track width defining portion taken in the direction orthogonal to the medium facing surface is called a neck height. The smaller the neck height, the better is the overwrite property.
A magnetic head used for a magnetic disk drive such as a hard disk drive is typically provided in a slider. The slider has the above-mentioned medium facing surface. The medium facing surface has an air-inflow-side end and an air-outflow-side end. The slider slightly flies over the surface of the recording medium by means of the airflow that comes from the air-inflow-side end into the space between the medium facing surface and the recording medium. The magnetic head is typically disposed near the air-outflow-side end of the medium facing surface of the slider. In a magnetic disk drive the magnetic head is aligned through the use of a rotary actuator, for example. In this case, the magnetic head moves over the recording medium along a circular orbit centered on the center of rotation of the rotary actuator. In such a magnetic disk drive, a tilt called a skew of the magnetic head is created with respect to the tangent of the circular track, in accordance with the position of the magnetic head across the tracks.
In a magnetic disk drive of the perpendicular magnetic recording system that exhibits a better capability of writing on a recording medium than the longitudinal magnetic recording system, in particular, if the above-mentioned skew is created, there arise problems, such as a phenomenon in which data stored on an adjacent track is erased when data is written on a specific track (that is hereinafter called adjacent track erasing) or unwanted writing is performed between adjacent two tracks. To achieve higher recording density, it is required to suppress adjacent track erasing. Unwanted writing between adjacent two tracks affects detection of servo signals for alignment of the magnetic head and the signal-to-noise ratio of a read signal.
A technique is known for preventing the problems resulting from the skew as described above, as disclosed in the Published U.S. Patent Application No. 2003/0151850A1, the Published Unexamined Japanese Patent Application 2003-203311, and the U.S. Pat. No. 6,504,675B1, for example. According to this technique, the end face of the track width defining portion located in the medium facing surface is made to have a shape in which the side located backward in the direction of travel of the recording medium (that is, the side located on the air-inflow-end side of the slider) is shorter than the opposite side. Typically, in the medium facing surface of a magnetic head, the end farther from the substrate is located forward in the direction of travel of the recording medium (that is, on the air-outflow-end side of the slider). Therefore, the above-mentioned shape of the end face of the track width defining portion located in the medium facing surface is such that the side closer to the substrate is shorter than the side farther from the substrate.
As a magnetic head for the perpendicular magnetic recording system, a magnetic head comprising a pole layer and a shield is known, as disclosed in the U.S. Pat. No. 4,656,546, for example. In the medium facing surface of this magnetic head, an end face of the shield is located forward of an end face of the pole layer along the direction of travel of the recording medium with a specific small space. Such a magnetic head will be hereinafter called a shield-type head. In the shield-type head, the shield prevents a magnetic flux from reaching the recording medium, the flux being generated from the end face of the pole layer and extending in directions except the direction perpendicular to the surface of the recording medium. The shield-type head achieves a further improvement in linear recording density.
The U.S. Pat. No. 4,672,493 discloses a magnetic head having a structure in which magnetic layers are provided forward and backward, respectively, in the direction of travel of the recording medium with respect to a middle magnetic layer to be the pole layer, and coils are disposed between the middle magnetic layer and the forward magnetic layer, and between the middle magnetic layer and the backward magnetic layer, respectively. This magnetic head is capable of increasing components perpendicular to the surface of the recording medium among components of the magnetic field generated from the medium-facing-surface-side end of the middle magnetic layer.
Consideration will now be given to a method of forming a pole layer in which the end face of the track width defining portion located in the medium facing surface has a shape in which the side closer to the substrate is shorter than the side farther from the substrate, as mentioned above. In prior art, frame plating has been often employed as a method of forming such a pole layer. According to the method of forming the pole layer by frame plating, an electrode film is first formed on a layer serving as a base of the pole layer. Next, a photoresist layer is formed on the electrode film. The photoresist layer is then patterned to form a frame having a groove whose shape corresponds to the pole layer. Next, plating is performed by feeding a current to the electrode film to form the pole layer in the groove. The frame is then removed. Next, portions of the electrode film except the portion below the pole layer are removed.
When frame plating is employed, it is difficult to form a groove having a small width in the photoresist layer by photolithography. Therefore, the problem is that it is difficult to reduce the track width when the pole layer is formed by frame plating. To solve this problem, it is possible that, after forming the pole layer by frame plating, both side portions of the track width defining portion are etched by dry etching such as ion beam etching so as to reduce the track width.
In the course of manufacturing magnetic heads, a plurality of magnetic head elements to be the magnetic heads are formed in a single substrate (wafer). The substrate in which the magnetic head elements are formed is cut such that the surface to be the medium facing surfaces appears. This surface is then polished to form the medium facing surfaces.
FIG. 44 illustrates an example of shape of the top surface of the pole layer when the track width is reduced by etching both side portions of the track width defining portion as described above. FIG. 44 illustrates a neighborhood of the boundary between the track width defining portion indicated with numeral 201 and the wide portion indicated with numeral 202 . In FIG. 44, ‘ABS’ indicates a region in which the medium facing surface is to be formed, ‘TW’ indicates the track width, and ‘NH’ indicates the neck height as designed.
When the track width TW is reduced by etching the side portions of the track width defining portion 201 , it is likely that the pole layer goes out of a desired shape. As a result, particularly when the neck height NH is small, it is likely that the track width defining portion 201 forms a shape in which the width varies depending on the location along the direction orthogonal to the medium facing surface (the vertical direction in FIG. 44), as shown in FIG. 44.
When the track width defining portion 201 has a shape as shown in FIG. 44, the neck height is strictly the length between the region ABS and the point at which the width of the track width defining portion 201 starts to be greater than the width thereof in the region ABS. However, if the neck height is thus defined, it is difficult to precisely determine the neck height when the track width defining portion 201 has the shape as shown in FIG. 44. Therefore, the neck height is defined as will be described below when the track width defining portion 201 has the shape as shown in FIG. 44. In the top surface of the pole layer, an imaginary line L 1 passes through the intersection point of the region ABS and the side portion of the track width defining portion 201 , and extends in the direction orthogonal to the region ABS. An imaginary line L 2 extends from a straight line portion of the side portion of the wide portion 202 connected to the side portion of the portion 201 and extends in the direction in which the straight line portion extends. The intersection point of the imaginary lines L 1 and L 2 is defined as C. The distance between the region ABS and the point C is defined as the neck height. The neck height as thus defined is nearly equal to the neck height NH as designed.
When the track width defining portion 201 has the shape as shown in FIG. 44, it is impossible to obtain the track width TW in the course of manufacturing process of the magnetic heads unless the location of the region ABS in which the medium facing surface is to be formed is known. In prior art, however, it is impossible to obtain a correct location of the region ABS in the course of manufacturing process of the magnetic heads, and it is therefore impossible to obtain a correct track width TW. Consequently, in prior art, even if the track width TW is out of a desired value in the course of manufacturing process of the magnetic heads, it is impossible to recognize that until the head is completed, which results in a reduction in efficiency in manufacturing the magnetic heads.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the invention to provide a method of manufacturing magnetic heads and a magnetic head substructure for allowing the track width to be obtained with accuracy in the course of manufacturing process of the magnetic heads.
Each of magnetic heads manufactured by the manufacturing method of the invention comprises: a medium facing surface that faces toward a recording medium; a coil that generates a magnetic field corresponding to data to be written on the recording medium; and a pole layer that incorporates a track width defining portion having an end face located in the medium facing surface, the pole layer allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough and generating a write magnetic field for writing the data on the recording medium.
The method of manufacturing the magnetic heads of the invention comprises the steps of: fabricating a magnetic head substructure by forming a plurality of sets of the pole layer and the coil in a substrate, wherein a plurality of rows of pre-head portions that will be the respective magnetic heads later are aligned in the substructure; and fabricating the magnetic heads by separating the pre-head portions from one another through cutting the substructure. The step of fabricating the substructure includes the step of forming a plurality of indicators each of which serves as a reference for indicating the location of a region in which the medium facing surfaces of the magnetic heads are to be formed.
According to the method of manufacturing the magnetic heads of the invention, a plurality of indicators are formed in the step of fabricating the substructure. Each of the indicators serves as a reference for indicating the location of a region in which the medium facing surfaces of the magnetic heads are to be formed. As a result, in the course of manufacturing process of the magnetic heads, it is possible to obtain the location of the region in which the medium facing surfaces are to be formed. It is thereby possible to obtain the track width with accuracy.
In each of the magnetic heads manufactured by the method of the invention, the end face of the track width defining portion located in the medium facing surface may have: a first side close to the substrate; a second side located opposite to the first side; a third side connecting an end of the first side to an end of the second side; and a fourth side connecting the other end of the first side to the other end of the second side. In addition, the second side may define the track width, and the end face of the track width defining portion may have a width that decreases as the distance from the first side decreases.
In the method of the invention, the indicators may be formed on both sides of the track width defining portion, the sides being opposed to each other in a direction of width of the defining portion, in the step of forming the indicators. In this case, in the substructure, each of the pole layers and the indicators may be conductive, and the indicators may be electrically connected to the respective pole layers.
In the method of the invention, the step of fabricating the substructure may further include the step of forming an encasing layer having grooves that accommodate the pole layers, and the pole layers may be disposed in the grooves of the encasing layer. In this case, in the step of forming the indicators, the indicators may be formed of a layer located at a height the same as the height at which the pole layers are located.
In the method of the invention, the step of fabricating the substructure may further include the step of forming a magnetic layer having portions that will be the pole layers, and the indicators may be made up of other portions of the magnetic layer. In this case, the step of fabricating the substructure may further include the step of forming an encasing layer having a groove that accommodates the magnetic layer, and the magnetic layer may be disposed in the groove of the encasing layer.
In the method of the invention, the step of fabricating the substructure may further include the step of forming a magnetic layer having portions that will be the pole layers, and the indicators may be made up of a layer other than the magnetic layer. In this case, the step of fabricating the substructure may further include the step of forming an encasing layer having a first groove that accommodates the magnetic layer and second grooves that accommodate the indicators, the magnetic layer may be formed in the first groove of the encasing layer, and the indicators may be formed in the second grooves.
In the method of the invention, the indicators may be formed of a layer located closer to the substrate than the pole layers in the step of forming the indicators.
In the method of the invention, the indicators may be formed of a layer having conductivity.
In the method of the invention, the step of fabricating the substructure may further include the step of forming an encasing layer having grooves that accommodate the pole layers and other grooves that form the indicators.
In the method of the invention, each of the indicators may have an end that is parallel to the region in which the medium facing surfaces are to be formed, and the location of the end may serve as a reference for indicating the location of the region. In this case, the distance between the location of the reference and the region may fall within a range of 0 to 1.0 μm inclusive.
In the method of the invention, each of the indicators may have two ends that are parallel to the region in which the medium facing surfaces are to be formed, and the location of the middle between the two ends may serve as a reference for indicating the location of the region. In this case, the distance between the location of the reference and the region may fall within a range of 0 to 1.0 μm inclusive.
In the method of the invention, in the substructure, the distance between the track width defining portion and the indicators taken in the direction of width of the defining portion may fall within a range of 0.1 to 5.0 μm inclusive.
In the method of the invention, the indicators may be located in a region that will not remain in the magnetic heads.
In the method of the invention, at least part of each of the indicators may be located in a region that will remain in the magnetic heads. In this case, the part of each of the indicators that remains in the magnetic heads may indicate the length of the track width defining portion taken in the direction orthogonal to the medium facing surface. The method of manufacturing the magnetic heads may further comprise the step of measuring the length of the track width defining portion taken in the direction orthogonal to the medium facing surface by measuring the length of the part of each of the indicators that remains in the magnetic heads taken in the direction orthogonal to the medium facing surface, the step being performed after the step of fabricating the magnetic heads.
In the method of the invention, the step of fabricating the magnetic heads may include the step of forming the medium facing surfaces by polishing a surface formed by cutting the substructure.
In the method of the invention, the magnetic heads may be those used for a perpendicular magnetic recording system.
A magnetic head substructure of the invention are used for manufacturing magnetic heads. Each of the magnetic heads comprises: a medium facing surface that faces toward a recording medium; a coil that generates a magnetic field corresponding to data to be written on the recording medium; and a pole layer that incorporates a track width defining portion having an end face located in the medium facing surface, the pole layer allowing a magnetic flux corresponding to the field generated by the coil to pass therethrough and generating a write magnetic field for writing the data on the recording medium.
The substructure of the invention comprises: a substrate; a plurality of sets of the pole layer and the coil formed in the substrate such that a plurality of rows of pre-head portions that will be the respective magnetic heads later are aligned; and a plurality of indicators each of which serves as a reference for indicating a region in which the medium facing surfaces of the magnetic heads are to be formed.
The substructure of the invention includes a plurality of indicators each of which serves as a reference for indicating the location of a region in which the medium facing surfaces of the magnetic heads are to be formed. As a result, in the course of manufacturing process of the magnetic heads, it is possible to obtain the location of the region in which the medium facing surfaces are to be formed. It is thereby possible to obtain the track width with accuracy.
In each of the magnetic heads manufactured through the use of the substructure of the invention, the end face of the track width defining portion located in the medium facing surface may have: a first side close to the substrate; a second side located opposite to the first side; a third side connecting an end of the first side to an end of the second side; and a fourth side connecting the other end of the first side to the other end of the second side. In addition, the second side may define the track width, and the end face of the track width defining portion may have a width that decreases as the distance from the first side decreases.
In the substructure of the invention, the indicators may be provided on both sides of the track width defining portion, the sides being opposed to each other in a direction of width of the defining portion. In this case, each of the pole layers and the indicators may be conductive, and the indicators may be electrically connected to the respective pole layers.
The substructure of the invention may further comprise an encasing layer having grooves that accommodate the pole layers. In this case, the indicators may be made of a layer located at a height the same as the height at which the pole layers are located.
The substructure of the invention may further comprise a magnetic layer having portions that will be the pole layers, and the indicators may be made up of other portions of the magnetic layer. In this case, the substructure may further comprise an encasing layer having a groove that accommodates the magnetic layer.
The substructure of the invention may further comprise a magnetic layer having portions that will be the pole layers, wherein the indicators are made up of a layer other than the magnetic layer. In this case, the substructure may further comprise an encasing layer having a first groove that accommodates the magnetic layer and second grooves that accommodate the indicators.
In the substructure of the invention, the indicators may be made of a layer located closer to the substrate than the pole layers.
In the substructure of the invention, the indicators may be made of a layer having conductivity.
The substructure of the invention may further comprise an encasing layer having grooves that accommodate the pole layers and other grooves that form the indicators.
In the substructure of the invention, each of the indicators may have an end that is parallel to the region in which the medium facing surfaces are to be formed, and the location of the end may serve as a reference for indicating the location of the region. In this case, the distance between the location of the reference and the region may fall within a range of 0 to 1.0 μm inclusive.
In the substructure of the invention, each of the indicators may have two ends that are parallel to the region in which the medium facing surfaces are to be formed, and the location of the middle between the two ends may serve as a reference for indicating the location of the region. In this case, the distance between the location of the reference and the region may fall within a range of 0 to 1.0 μm inclusive.
In the substructure of the invention, the distance between the track width defining portion and the indicators taken in the direction of width of the defining portion may fall within a range of 0.1 to 5.0 μm inclusive.
In the substructure of the invention, the indicators may be located in a region that will not remain in the magnetic heads.
In the substructure of the invention, at least part of each of the indicators may be located in a region that will remain in the magnetic heads. In this case, the part of each of the indicators that remains in the magnetic heads may indicate the length of the track width defining portion taken in the direction orthogonal to the medium facing surface.
In the substructure of the invention, the magnetic heads may be those used for the perpendicular magnetic recording system.
According to the method of manufacturing the magnetic heads of the invention, in the step of fabricating the substructure, a plurality of indicators are formed each of which serves as the reference for indicating the location of the region in which the medium facing surfaces of the magnetic heads are to be formed. As a result, according to the invention, it is possible to obtain the location of the region in which the medium facing surfaces are to be formed, in the course of manufacturing process of the magnetic heads. It is thereby possible to obtain the track width with accuracy.
The magnetic head substructure of the invention includes a plurality of indicators each of which serves as the reference for indicating the location of the region in which the medium facing surfaces of the magnetic heads are to be formed. As a result, according to the invention, it is possible to obtain the location of the region in which the medium facing surfaces are to be formed, in the course of manufacturing process of the magnetic heads. It is thereby possible to obtain the track width with accuracy.
In each of the magnetic heads manufactured by the method of the invention or manufactured through the use of the substructure of the invention, the end face of the track width defining portion located in the medium facing surface may have: a first side close to the substrate; a second side located opposite to the first side; a third side connecting an end of the first side to an end of the second side; and a fourth side connecting the other end of the first side to the other end of the second side. In addition, the second side may define the track width, and the end face of the track width defining portion may have a width that decreases as the distance from the first side decreases. In this case, it is possible to prevent the problems resulting from the skew.
In the method of the invention or the substructure of the invention, the indicators may be provided on both sides of the track width defining portion, the sides being opposed to each other in the direction of width of the defining portion. In this case, it is possible to obtain the location of the region in which the medium facing surfaces are to be formed with higher accuracy, using the two indicators provided on both sides of the track width defining portion as the reference.
In the method of the invention or the substructure of the invention, each of the pole layers and the two indicators provided on both sides of the track width defining portion opposed to each other in the direction of width of the defining portion may be conductive, and the indicators may be electrically connected to the respective pole layers. In this case, when the indicators are observed by an electron microscope, it is possible to prevent electric charges from accumulating on the indicators. It is thereby possible to obtain correct images of the indicators. It is thereby possible to obtain the location of the region in which the medium facing surfaces are to be formed with higher accuracy.
In the method of the invention or the substructure of the invention, the part of each of the indicators that remains in the magnetic heads may indicate the length of the track width defining portion taken in the direction orthogonal to the medium facing surface. In this case, after the magnetic heads are completed, it is possible to measure the length of the track width defining portion taken in the direction orthogonal to the medium facing surface by measuring the length of the part of each of the indicators that remains in the magnetic heads taken in the direction orthogonal to the medium facing surface.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates indicator portions of a first embodiment of the invention.
FIG. 2 is a front view of the medium facing surface of a magnetic head of the first embodiment of the invention.
FIG. 3 is a cross-sectional view for illustrating the configuration of the magnetic head of the first embodiment of the invention.
FIG. 4 is a top view of the pole layer of the magnetic head of the first embodiment of the invention.
FIG. 5A and FIG. 5B are views for illustrating a step of a method of manufacturing the magnetic head of the first embodiment of the invention.
FIG. 6A and FIG. 6B are views for illustrating the main part of FIG. 5A and FIG. 5B.
FIG. 7A and FIG. 7B are views for illustrating a step that follows the step shown in FIG. 5A and FIG. 5B.
FIG. 8A and FIG. 8B are views for illustrating the main part of FIG. 7A and FIG. 7B.
FIG. 9A and FIG. 9B are views for illustrating a step that follows the step shown in FIG. 7A and FIG. 7B.
FIG. 10A and FIG. 10B are views for illustrating the main part of FIG. 9A and FIG. 9B.
FIG. 11A and FIG. 11B are views for illustrating a step that follows the step shown in FIG. 9A and FIG. 9B.
FIG. 12A and FIG. 12B are views for illustrating the main part of FIG. 11A and FIG. 11B.
FIG. 13A and FIG. 13B are views for illustrating a step that follows the step shown in FIG. 11A and FIG. 11B.
FIG. 14A and FIG. 14B are views for illustrating a step that follows the step shown in FIG. 13A and FIG. 13B.
FIG. 15A and FIG. 15B are views for illustrating a step that follows the step shown in FIG. 14A and FIG. 14B.
FIG. 16A and FIG. 16B are views for illustrating a step that follows the step shown in FIG. 15A and FIG. 15B.
FIG. 17 is a top view of a magnetic head substructure of the first embodiment of the invention.
FIG. 18 is a perspective view for schematically illustrating the configuration of a lapping apparatus used in the method of manufacturing the magnetic head of the first embodiment of the invention.
FIG. 19 is a block diagram illustrating an example of circuit configuration of the lapping apparatus of FIG. 18.
FIG. 20A and FIG. 20B are views for illustrating a modification example of the method of manufacturing the magnetic head of the first embodiment of the invention.
FIG. 21 illustrates indicator portions of a second embodiment of the invention.
FIG. 22 illustrates an example of arrangement of indicator portions of a third embodiment of the invention.
FIG. 23 illustrates another example of arrangement of the indicator portions of the third embodiment of the invention.
FIG. 24 illustrates indicator portions of a fourth embodiment of the invention.
FIG. 25A and FIG. 25B are views for illustrating a step of a method of manufacturing a magnetic head of a fifth embodiment of the invention.
FIG. 26A and FIG. 26B are views for illustrating the main part of FIG. 25A and FIG. 25B.
FIG. 27A and FIG. 27B are views for illustrating a step that follows the step shown in FIG. 25A and FIG. 25B.
FIG. 28A and FIG. 28B are views for illustrating the main part of FIG. 27A and FIG. 27B.
FIG. 29A and FIG. 29B are views for illustrating a step that follows the step shown in FIG. 27A and FIG. 27B.
FIG. 30A and FIG. 30B are views for illustrating a step that follows the step shown in FIG. 29A and FIG. 29B.
FIG. 31A and FIG. 31B are views for illustrating a step that follows the step shown in FIG. 30A and FIG. 30B.
FIG. 32A and FIG. 32B are views for illustrating a step that follows the step shown in FIG. 31A and FIG. 31B.
FIG. 33A and FIG. 33B are views for illustrating a step that follows the step shown in FIG. 32A and FIG. 32B.
FIG. 34 illustrates indicator portions of a sixth embodiment of the invention.
FIG. 35A and FIG. 35B are views for illustrating a step of a method of manufacturing a magnetic head of the sixth embodiment of the invention.
FIG. 36A and FIG. 36B are views for illustrating a step that follows the step shown in FIG. 35A and FIG. 35B.
FIG. 37A and FIG. 37B are views for illustrating a step that follows the step shown in FIG. 36A and FIG. 36B.
FIG. 38A and FIG. 38B are views for illustrating a step that follows the step shown in FIG. 37A and FIG. 37B.
FIG. 39A and FIG. 39B are views for illustrating a step that follows the step shown in FIG. 38A and FIG. 38B.
FIG. 40A and FIG. 40B are views for illustrating a step that follows the step shown in FIG. 39A and FIG. 39B.
FIG. 41A and FIG. 41B are views for illustrating a step that follows the step shown in FIG. 40A and FIG. 40B.
FIG. 42A and FIG. 42B are views for illustrating a step that follows the step shown in FIG. 41A and FIG. 41B.
FIG. 43A and FIG. 43B are views for illustrating a step that follows the step shown in FIG. 42A and FIG. 42B.
FIG. 44 is a view for illustrating an example of shape of a pole layer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
First Embodiment
Preferred embodiments of the invention will now be described in detail with reference to the accompanying drawings. Reference is now made to FIG. 2 and FIG. 3 to describe a manufacturing method and the configuration of a magnetic head manufactured through the use of a magnetic head substructure of a first embodiment of the invention. Here, a magnetic head for the perpendicular magnetic recording system will be described as an example of the magnetic head. FIG. 2 is a front view for illustrating the medium facing surface of the magnetic head of the embodiment. FIG. 3 is a cross-sectional view for illustrating the configuration of the magnetic head of the embodiment. FIG. 3 illustrates a cross section orthogonal to the medium facing surface and a surface of a substrate. The arrow indicated with T in FIG. 3 shows the direction of travel of a recording medium.
As shown in FIG. 2 and FIG. 3, the magnetic head of the embodiment comprises: a substrate 1 made of a ceramic such as aluminum oxide and titanium carbide (Al 2 O 3 —TiC); an insulating layer 2 made of an insulating material such as alumina (Al 2 O 3 ) and disposed on the substrate 1 ; a bottom shield layer 3 made of a magnetic material and disposed on the insulating layer 2 ; a bottom shield gap film 4 that is an insulating film disposed on the bottom shield layer 3 ; a magnetoresistive (MR) element 5 as a read element disposed on the bottom shield gap film 4 ; a top shield gap film 6 that is an insulating film disposed on the MR element 5 ; and a top shield layer 7 made of a magnetic material and disposed on the top shield gap film 6 . The portion from the bottom shield layer 3 to the top shield layer 7 make up the read head.
The MR element 5 has an end that is located in the medium facing surface 30 that faces toward a recording medium. The MR element 5 may be an element made of a magneto-sensitive film that exhibits a magnetoresistive effect, such as an anisotropic magnetoresistive (AMR) element, a giant magnetoresistive (GMR) element, or a tunnel magnetoresistive (TMR) element.
The magnetic head further comprises: an insulating layer 8 made of an insulating material and disposed on the top shield layer 7 ; a coil 9 formed on the insulating layer 8 ; an insulating layer 10 made of an insulating material and disposed around the coil 9 and in the space between adjacent ones of the turns of the coil 9 ; and an insulating layer 11 made of an insulating material and disposed around the insulating layer 10 . The coil 9 is flat-whorl-shaped. The coil 9 and the insulating layers 10 and 11 have flattened top surfaces. The insulating layers 8 and 11 are made of alumina, for example. The insulating layer 10 is made of photoresist, for example. The coil 9 is made of a conductive material such as copper.
The magnetic head further comprises an encasing layer 12 made of a nonmagnetic material and disposed on the flattened top surfaces of the coil 9 and the insulating layers 10 and 11 . The encasing layer 12 has a groove 120 that opens in the top surface thereof and that accommodates the pole layer described later. Although the groove 120 does not penetrate the encasing layer 12 in FIG. 2 and FIG. 3, the groove 120 may penetrate the encasing layer 12 . The encasing layer 12 may be made of any of alumina, silicon oxide (SiO x ), and silicon oxynitride (SiON), for example.
The magnetic head further comprises a polishing stopper layer 13 made of a nonmagnetic conductive material and disposed on the top surface of the encasing layer 12 . The polishing stopper layer 13 has an opening 13 a that penetrates, and the edge of the opening 13 a is located directly above the edge of the groove 120 in the top surface of the encasing layer 12 . The polishing stopper layer 13 may be made of any of Ta, Mo, W, Ti, Ru, Rh, Re, Pt, Pd, Ir, TiN, TiW and NiCr, for example.
The magnetic head further comprises the pole layer 16 disposed in the groove 120 . The pole layer 16 incorporates: a first layer 161 located closer to the surface of the groove 120 ; and a second layer 162 located farther from the surface of the groove 120 . The polishing stopper layer 13 and the pole layer 16 have flattened top surfaces.
Each of the first layer 161 and the second layer 162 is made of a magnetic material. The first layer 161 may be made of any of CoFeN, CoNiFe and NiFe, for example. The second layer 162 may be made of any of NiFe, CoNiFe and CoFe, for example.
The magnetic head further comprises a gap layer 18 disposed on the flattened top surfaces of the polishing stopper layer 13 and the pole layer 16 . The gap layer 18 has an opening located at a distance from the medium facing surface 30 . The gap layer 18 may be made of an insulating material such as alumina or a nonmagnetic metal material such as Ru, NiCu, Ta, W or NiB.
The magnetic head further comprises a shield layer 20 . The shield layer 20 has: a first layer 20 A disposed on the gap layer 18 ; a second layer 20 C disposed on the first layer 20 A; a yoke layer 20 B disposed on a portion of the pole layer 16 where the opening of the gap layer 18 is formed; a coupling layer 20 D disposed on the yoke layer 20 B; and a third layer 20 E disposed to couple the second layer 20 C to the coupling layer 20 D. The first layer 20 A, the yoke layer 20 B, the second layer 20 C, the coupling layer 20 D and the third layer 20 E are each made of a magnetic material. These layers 20 A to 20 E may be made of any of CoFeN, CoNiFe and NiFe, for example.
The magnetic head further comprises a nonmagnetic layer 21 made of a nonmagnetic material and disposed around the yoke layer 20 B. A portion of the nonmagnetic layer 21 is disposed on a side of the first layer 20 A. The nonmagnetic layer 21 is made of an inorganic insulating material such as alumina or coating glass. Alternatively, the nonmagnetic layer 21 may be made up of a layer of a nonmagnetic metal material and a layer of an insulating material disposed thereon. In this case, the nonmagnetic metal material may be a refractory metal such as Ta, Mo, Nb, W, Cr, Ru, Cu or Ni.
The magnetic head further comprises: an insulating layer 22 disposed on regions of the top surfaces of the yoke layer 20 B and the nonmagnetic layer 21 in which a coil described later is disposed; the coil 23 disposed on the insulating layer 22 ; an insulating layer 24 disposed around the coil 23 and in the space between adjacent ones of the turns of the coil 23 ; and an insulating layer 25 disposed on the coil 23 and the insulating layer 24 . The coil 23 is flat-whorl-shaped. A portion of the coil 23 passes between the second layer 20 C and the coupling layer 20 D. The coil 23 is made of a conductive material such as copper. The second layer 20 C, the coupling layer 20 D, the coil 23 and the insulating layer 24 have flattened top surfaces. The insulating layer 24 is made of photoresist, for example. The insulating layers 22 and 25 are made of alumina, for example.
The portion from the coil 9 to the third layer 20 E of the shield layer 20 make up the write head. Although not shown, the magnetic head further comprises a protection layer for covering the shield layer 20 .
As described so far, the magnetic head of the embodiment comprises the medium facing surface 30 that faces toward a recording medium, the read head, and the write head. The read head and the write head are stacked on the substrate 1 . The read head is disposed backward in the direction T of travel of the recording medium (that is, on the air-inflow-end side of the slider). The write head is disposed forward in the direction T of travel of the recording medium (that is, on the air-outflow-end side of the slider).
The read head comprises the MR element 5 as the read element, and the bottom shield layer 3 and the top shield layer 7 for shielding the MR element 5 . Portions of the bottom shield layer 3 and the top shield layer 7 that are located on a side of the medium facing surface 30 are opposed to each other, the MR element 5 being placed between these portions. The read head further comprises: the bottom shield gap film 4 disposed between the MR element 5 and the bottom shield layer 3 ; and the top shield gap film 6 disposed between the MR element 5 and the top shield layer 7 .
The write head comprises the coil 9 , the encasing layer 12 , the polishing stopper layer 13 , the pole layer 16 , the gap layer 18 , the shield layer 20 , and the coil 23 . The coils 9 and 23 generate a magnetic field corresponding to data to be written on the recording medium. The coil 9 is not a component requisite for the write head and may be omitted.
The pole layer 16 has an end face located in the medium facing surface 30 . The pole layer 16 allows the magnetic flux corresponding to the field generated by the coil 23 to pass therethrough and generates a write magnetic field for writing the data on the medium by using the perpendicular magnetic recording system.
The shield layer 20 has an end located in the medium facing surface 30 , and has a portion located away from the medium facing surface 30 and coupled to the pole layer 16 . The gap layer 18 is made of a nonmagnetic material and provided between the pole layer 16 and the shield layer 20 .
In the medium facing surface 30 , the end face of the shield layer 20 is disposed forward of the end face of the track width defining portion 16 A along the direction T of travel of the recording medium with a specific space created by the thickness of the gap layer 18 . At least part of the coil 23 is disposed between the pole layer 16 and the shield layer 20 and insulated from the pole layer 16 and the shield layer 20 .
The shield layer 20 has: the first layer 20 A disposed adjacent to the gap layer 18 ; the second layer 20 C disposed on a side of the first layer 20 A farther from the gap layer 18 ; the yoke layer 20 B disposed on the portion of the pole layer 16 where the opening of the gap layer 18 is formed; the coupling layer 20 D disposed on the yoke layer 20 B; and the third layer 20 E disposed to couple the second layer 20 C to the coupling layer 20 D. The second layer 20 C is disposed between the medium facing surface 30 and the at least part of the coil 23 .
FIG. 4 is a top view of the pole layer 16 . As shown in FIG. 4, the pole layer 16 incorporates the track width defining portion 16 A and a wide portion 16 B. The track width defining portion 16 A has an end located in the medium facing surface 30 and has a uniform width. The wide portion 16 B is coupled to the other end of the track width defining portion 16 A and has a width greater than the width of the track width defining portion 16 A. The wide portion 16 B is equal in width to the track width defining portion 16 A at the interface with the track width defining portion 16 A, and gradually increases in width as the distance from the medium facing surface 30 increases and then maintains a specific width to the end of the wide portion 16 B. Here, the length of the track width defining portion 16 A taken in the direction orthogonal to the medium facing surface 30 is called a neck height NH. The neck height NH falls within a range of 0.1 to 0.3 μm inclusive, for example.
As shown in FIG. 2, the end face of the track width defining portion 16 A located in the medium facing surface 30 has: a first side A 1 close to the substrate 1 ; a second side A 2 opposite to the first side A 1 ; a third side A 3 connecting an end of the first side A 1 to an end of the second side A 2 ; and a fourth side A 4 connecting the other end of the first side A 1 to the other end of the second side A 2 . The second side A 2 defines the track width. The width of the end face of the track width defining portion 16 A located in the medium facing surface 30 decreases as the distance from the first side A 1 decreases.
The length of the second side A 2 , that is, the track width, falls within a range of 0.08 to 0.12 μm inclusive, for example. The thickness of the pole layer 16 falls within a range of 0.20 to 0.30 μm inclusive, for example. Each of the third side A 3 and the fourth side A 4 forms an angle that falls within a range of 5 to 12 degrees inclusive, for example, with respect to the direction orthogonal to the top surface of the substrate 1 . The thickness of the gap layer 18 falls within a range of 30 to 60 nm inclusive, for example.
The polishing stopper layer 13 is disposed on the top surface of the encasing layer 12 . The polishing stopper layer 13 has the opening 13 a that penetrates, and the edge of the opening 13 a is located directly above the edge of the groove 120 in the top surface of the encasing layer 12 . The polishing stopper layer 13 has a thickness that falls within a range of 20 to 60 nm inclusive, for example.
The pole layer 16 incorporates: the first layer 161 located closer to the surface of the groove 120 ; and the second layer 162 located farther from the surface of the groove 120 . The first layer 161 has a thickness that falls within a range of 40 to 100 nm inclusive, for example.
The first layer 20 A of the shield layer 20 has: a first end located in the medium facing surface 30 ; and a second end opposite to the first end. The second layer 20 C of the shield layer 20 also has: a first end located in the medium facing surface 30 ; and a second end opposite to the first end. The second end of the first layer 20 A defines the throat height TH. That is, as shown in FIG. 3, the throat height TH is the minimum distance between the first end and the second end of the portion of the first layer 20 A facing toward the pole layer 16 with the gap layer 18 disposed in between. The throat height TH falls within a range of 0.1 to 0.3 μm inclusive, for example. The minimum distance between the first end and the second end of the portion of the second layer 20 C facing toward the pole layer 16 with the gap layer 18 and the first layer 20 A disposed in between falls within a range of 0.5 to 0.8 μm inclusive, for example. The first layer 20 A and the yoke layer 20 B have a thickness that falls within a range of 0.3 to 0.8 μm inclusive, for example. The second layer 20 C and the coupling layer 20 D have a thickness that falls within a range of 2.0 to 2.5 μm inclusive, for example. The third layer 20 E has a thickness that falls within a range of 2.0 to 3.0 μm inclusive, for example. The coil 23 has a thickness that is equal to or smaller than the thickness of the second layer 20 C and that falls within a range of 2.0 to 2.5 μm inclusive, for example.
In the drawings of the present patent application such as FIG. 3, the pole layer 16 is shown greater in thickness than the yoke layer 20 B to illustrate details of the structure around the pole layer 16 . However, the pole layer 16 actually has a thickness that is nearly equal to or smaller than the thickness of the yoke layer 20 B, for example.
The magnetic head of the embodiment writes data on a recording medium by using the write head and reads data written on the recording medium by using the read head. In the write head, the coil 23 generates a magnetic field that corresponds to the data to be written on the medium. The pole layer 16 and the shield layer 20 form a magnetic path through which a magnetic flux corresponding to the magnetic field generated by the coil 23 passes. The pole layer 16 allows the flux corresponding to the field generated by the coil 23 to pass and generates a write magnetic field used for writing the data on the medium through the use of the perpendicular magnetic recording system. The shield layer 20 takes in a disturbance magnetic field applied from outside the magnetic head to the magnetic head. It is thereby possible to prevent erroneous writing on the recording medium caused by the disturbance magnetic field intensively taken in into the pole layer 16 .
According to the embodiment, in the medium facing surface 30 , the end face of the shield layer 20 is disposed forward of the end face of the track width defining portion 16 A along the direction T of travel of the recording medium (that is, on the air-outflow-end side of the slider) with a specific small space created by the gap layer 18 . The location of an end of the bit pattern written on the recording medium is determined by the location of the end of the pole layer 16 that is closer to the gap layer 18 and located in the medium facing surface 30 . The shield layer 20 takes in a magnetic flux generated from the end face of the pole layer 16 located in the medium facing surface 30 and extending in directions except the direction orthogonal to the surface of the recording medium so as to prevent the flux from reaching the recording medium. It is thereby possible to prevent the direction of magnetization of the bit pattern already written on the medium from being changed due to the effect of the above-mentioned flux. According to the embodiment, an improvement in linear recording density is thus achieved.
According to the embodiment, as shown in FIG. 2, the end face of the track width defining portion 16 A located in the medium facing surface 30 has a width that decreases as the distance from the first side A 1 decreases. It is thereby possible to prevent the problems resulting from the skew.
Reference is now made to FIG. 5A to FIG. 16A, and FIG. 5B to FIG. 16B to describe a method of manufacturing the magnetic head of the embodiment and a magnetic head substructure of the embodiment. The method of manufacturing the magnetic head of the embodiment comprises the steps of: fabricating the magnetic head substructure in which a plurality of rows of pre-head portions to be the magnetic heads are aligned by forming components of a plurality of magnetic heads in a single substrate; and fabricating the magnetic heads by separating the pre-head portions through cutting the magnetic head substructure. One of the pre-head portions will now be described. Portions closer to the substrate 1 than the encasing layer 12 are omitted in FIG. 5A to FIG. 16A, and FIG. 5B to FIG. 16B. ‘ABS’ indicates a region in which the medium facing surface is to be formed.
According to the method of manufacturing the magnetic head of the embodiment, as shown in FIG. 3, the insulating layer 2 , the bottom shield layer 3 and the bottom shield gap film 4 are first formed on the substrate 1 one by one. Next, the MR element 5 and a lead not shown that is connected to the MR element 5 are formed on the bottom shield gap film 4 . Next, the MR element 5 and the lead are covered with the top shield gap film 6 . Next, the top shield layer 7 and the insulating layer 8 are formed one by one on the top shield gap film 6 . Next, the coil 9 and the insulating layers 10 and 11 are formed on the insulating layer 8 . Next, the top surfaces of the coil 9 and the insulating layers 10 and 11 are flattened by chemical mechanical polishing (hereinafter referred to as CMP), for example.
FIG. 5A, FIG. 5B, FIG. 6A and FIG. 6B illustrate the following step. FIG. 5A shows the top surface of the layered structure obtained in the course of manufacturing process of the magnetic head. FIG. 5B shows a cross section of the layered structure orthogonal to the medium facing surface and the substrate. FIG. 5B is a cross section taken along line B-B of FIG. 5A. FIG. 6A is an enlarged view of neighborhood of the region ABS of FIG. 5A. FIG. 6B is a cross section corresponding to the region ABS of FIG. 6A. In the step, first, a nonmagnetic layer 12 P is formed on the flattened top surfaces of the coil 9 and the insulating layers 10 and 11 . The groove 120 will be formed later in the nonmagnetic layer 12 P and the nonmagnetic layer 12 P will be thereby formed into the encasing layer 12 . Next, the polishing stopper layer 13 is formed by sputtering, for example, on the nonmagnetic layer 12 P. Next, a photoresist layer having a thickness of 1.0 μm, for example, is formed on the polishing stopper layer 13 . The photoresist layer is then patterned to form a mask 31 for making the groove 120 of the encasing layer 12 . The mask 31 has an opening having a shape corresponding to the groove 120 .
Next, the polishing stopper layer 13 is selectively etched, using the mask 31 . The opening 13 a that penetrates is thereby formed in the polishing stopper layer 13 . The opening 13 a has a shape corresponding to the plane geometry of a magnetic layer 160 to be formed later. A portion of the magnetic layer 160 will be formed into the pole layer 16 . Furthermore, a portion of the nonmagnetic layer 12 P exposed from the opening 13 a of the polishing stopper layer 13 is selectively etched so as to form the groove 120 in the nonmagnetic layer 12 P. The mask 31 is then removed. The nonmagnetic layer 12 P is formed into the encasing layer 12 by forming the groove 120 therein. The polishing stopper layer 13 indicates the level at which polishing to be performed later is stopped. The edge of the opening 13 a of the polishing stopper layer 13 is located directly above the edge of the groove 120 located in the top surface of the encasing layer 12 .
The etching of each of the polishing stopper layer 13 and the nonmagnetic layer 12 P is performed by reactive ion etching or ion beam etching, for example. The etching for forming the groove 120 in the nonmagnetic layer 12 P is performed such that the walls of the groove 120 corresponding to both sides of the track width defining portion 16 A of the pole layer 16 each form an angle that falls within a range of 5 to 12 degrees inclusive, for example, with respect to the direction orthogonal to the top surface of the substrate 1 .
As shown in FIG. 5A and FIG. 6A, the groove 120 includes a portion 120 a corresponding to the pole layer, indicator portions 120 b and 120 c , and a coupling portion 120 d . The portion 120 a corresponding to the pole layer is a portion in which the pole layer 16 will be placed later. The portion 120 a is shown as a portion of the groove 120 on the right hand of the region ABS in FIG. 5A, and a portion of the groove 120 located higher than the region ABS in FIG. 6A. The indicator portions 120 b and 120 c correspond to the indicators of the invention, and each serve as a reference for indicating the location of the ABS. The shape of each of the indicator portions 120 b and 120 c in the top surface of the nonmagnetic layer 12 P is rectangular. The coupling portion 120 d is a portion of the groove 120 for coupling the portion 120 a to the indicator portions 120 b and 120 c . The portion 120 a corresponds to one of the ‘grooves that accommodate the pole layers’ of the invention. The indicator portions 120 b and 120 c correspond to the ‘other grooves that form the indicators’.
Reference is now made to FIG. 1 to describe the indicator portions 120 b and 120 c in detail. FIG. 1 shows the indicator portions 120 b and 120 c and a neighborhood thereof. In FIG. 5A to FIG. 16A and FIG. 5B to FIG. 16B, the track width is shown greater, compared with FIG. 1, to illustrate details of the portion around the pole layer 16 . As shown in FIG. 1, the indicator portion 120 b has two ends 120 b 1 and 120 b 2 each of which is parallel to the region ABS. Similarly, the indicator portion 120 c has two ends 120 c 1 and 120 c 2 each of which is parallel to the region ABS. The ends 120 b 1 and 120 c 1 are located closer to the region ABS than the ends 120 b 2 and 120 c 2 . The distance between the region ABS and the end 120 b 1 is equal to the distance between the region ABS and the end 120 c 1 . Similarly, the distance between the region ABS and the end 120 b 2 is equal to the distance between the region ABS and the end 120 c 2 . In the embodiment, the location of the ends 120 b 1 and 120 c 1 serves as a reference for indicating the location of the region ABS. Therefore, the distance D 1 between the region ABS and the ends 120 b 1 and 120 c 1 is designed to be of a specific value. Furthermore, the distance between the indicator portion 120 b and the track width defining portion 16 A taken in the direction of width thereof is equal to the distance between the indicator portion 120 c and the track width defining portion 16 A. This distance is defined as D 3 .
Next, the opening 13 a of the polishing stopper layer 13 is observed, using an electron microscope. It is preferred to use a critical dimension measurement scanning electron microscope as the electron microscope. Since the edge of the opening 13 a is located directly above the edge of the groove 120 located in the top surface of the encasing layer 12 , the shape of the opening 13 a coincides with the shape of the groove 120 taken in the top surface of the encasing layer 12 . Therefore, it is possible to obtain the shape of the groove 120 taken in the top surface of the encasing layer 12 by observing the opening 13 a.
By observing the opening 13 a , the location of the region ABS is obtained in the following manner. As described above, the location of the ends 120 b 1 and 120 c 1 serves as the reference for indicating the location of the region ABS. Therefore, it is possible to obtain the location of the region ABS by observing the opening 13 a and measuring the location of the ends 120 b 1 and 120 c 1 . If the distance D 1 between the region ABS and the ends 120 b 1 , 120 c 1 is other than zero, the region ABS is placed in a location away from the ends 120 b 1 and 120 c 1 by the distance D 1 . If the distance D 1 between the region ABS and the ends 120 b 1 , 120 c 1 is zero, the location of the region ABS is the location of the ends 120 b 1 and 120 c 1 .
As shown in FIG. 2, the track width is equal to the length of the second side A 2 of the end face of the track width defining portion 16 A located in the medium facing surface 30 . The track width is equal to the width of the groove 120 taken in the top surface of the encasing layer 12 at the location of the region ABS. Therefore, it is possible to obtain the track width by measuring the width of the groove 120 in the top surface of the encasing layer 12 at the location of the region ABS.
The indicator portions 120 b and 120 c are located at a height the same as the portion 120 a corresponding to the pole layer in a neighborhood of the region in which the track width defining portion 16 A is located. Therefore, it is possible to determine the location of the region ABS and to obtain the track width through a single observation using an electron microscope.
The indicator portions 120 b and 120 c are disposed on both sides of the track width defining portion 16 A to be formed later, the sides being opposed to each other in the direction of width of the defining portion 16 A. In addition, the distance between the region ABS and the end 120 b 1 is equal to the distance between the region ABS and the end 120 c 1 . Therefore, the region ABS is parallel to an imaginary straight line that is in contact with the ends 120 b 1 and 120 c 1 . Based on the foregoing findings of the embodiment, it is possible to obtain the location of the region ABS with higher accuracy, referring to the two indicator portions 120 b and 120 c.
If the track width is as small as 0.08 to 0.12 μm, in particular, an image of high magnification is required to measure the track width by using an electron microscope. It is preferred that the distance D 1 is a distance that can be recognized in an image of high magnification obtained by an electron microscope when the indicator portions 120 b and 120 c and the neighborhood thereof are observed by the electron microscope. This indicates that the distance D 1 preferably falls within a range of 0 to 3.0 μm inclusive, and more preferably a range of 0 to 1.0 μm inclusive. Since it is possible to recognize the location of the region ABS with higher accuracy as the distance D 1 is reduced, the distance D 1 still more preferably falls within a range of 0 to 0.2 μm inclusive.
When the location of the region ABS is obtained from the location of the indicator portions 120 b and 120 c based on the image of high magnification obtained by the electron microscope as mentioned above, and the track width is measured based on the location of the region ABS, it is possible to recognize the location of the region ABS and the track width with higher accuracy as the distance D 3 is reduced. This indicates that the distance D 3 preferably falls within a range of 0.1 to 5.0 μm inclusive.
As shown in FIG. 44, when both sides of the track width defining portion are etched to reduce the track width, indicators near the track width defining portion disturb this etching. Therefore, in this case, it is difficult to dispose the indicators near the track width defining portion. According to the embodiment, in contrast, the pole layer 16 is disposed in the groove 120 of the encasing layer 12 , and the track width is determined by the width of the groove 120 taken in the top surface of the encasing layer 12 at the location of the region ABS. Therefore, the embodiment does not include any step of etching the sides of the track width defining portion. It is therefore possible to dispose the indicator portions 120 b and 120 c near the track width defining portion 16 A.
A case is now assumed wherein the polishing stopper layer 13 is not disposed on the top surface of the encasing layer 12 and the encasing layer 12 is made of an insulating material such as alumina. In this case, if an attempt is made to observe the groove 120 in the top surface of the encasing layer 12 by an electron microscope, electric charges accumulate on the top surface of the encasing layer 12 and it is impossible to obtain a correct image. According to the embodiment, in contrast, the polishing stopper layer 13 made of a conductive material is disposed on the top surface of the encasing layer 12 . In addition, the edge of the opening 13 a of the polishing stopper layer 13 is located directly above the edge of the groove 120 located in the top surface of the encasing layer 12 . As a result, a correct image is obtained when the polishing stopper layer 13 is observed by an electron microscope, and it is thereby possible to measure the geometry of the opening 13 a of the polishing stopper layer 13 with accuracy. It is thereby possible to measure the geometry of the groove 120 in the top surface of the encasing layer 12 with accuracy.
When the width of the groove 120 in the top surface of the encasing layer 12 at the location of the region ABS is measured by an electron microscope as described above, the width of the bottom of the groove 120 at the location of the region ABS may be measured at the same time. It is possible to obtain the angle formed by the wall of the groove 120 with respect to the direction orthogonal to the top surface of the substrate 1 by calculation if the depth of the groove 120 is obtained in addition to the width of the groove 120 in the top surface of the encasing layer 12 and the width of the bottom of the groove 120 . Here, it is possible to obtain the depth of the groove 120 by preparing a sample for measuring the depth of the groove 120 , cutting the sample so that the cross section shown in FIG. 6B appears, and observing the cross section by a scanning electron microscope, for example. If the nonmagnetic layer 12 P is etched by reactive ion etching, the etching rate of the nonmagnetic layer 12 P is nearly constant. Consequently, as long as the etching period is constant, the depth of the groove 120 is nearly uniform, too. Therefore, if the depth of the groove 120 is measured in advance by using the sample for measuring the depth, the depth of the groove 120 is obtained without measuring in the course of manufacturing process of the magnetic head.
FIG. 7A, FIG. 7B, FIG. 8A and FIG. 8B illustrate the following step. FIG. 7A shows the top surface of the layered structure in the course of manufacturing process of the magnetic head. FIG. 7B shows a cross section of the layered structure orthogonal to the medium facing surface and the substrate. FIG. 7B is a cross section taken along line B-B of FIG. 7A. FIG. 8A is an enlarged view of neighborhood of the region ABS of FIG. 7A. FIG. 8B is a cross section corresponding to the region ABS of FIG. 8A. In the step, a magnetic layer 161 P is formed in the groove 120 of the encasing layer 12 and on the polishing stopper layer 13 . The magnetic layer 161 P is formed by sputtering or ion beam deposition (hereinafter referred to as IBD), for example. If the magnetic layer 161 P is formed by sputtering, it is preferred to employ collimation sputtring or long throw sputtering.
FIG. 9A, FIG. 9B, FIG. 10A and FIG. 10B illustrate the following step. FIG. 9A shows the top surface of the layered structure in the course of manufacturing process of the magnetic head. FIG. 9B illustrates a cross section of the layered structure orthogonal to the medium facing surface and the substrate. FIG. 9B is a cross section taken along line B-B of FIG. 9A. FIG. 10A is an enlarged view of neighborhood of the region ABS of FIG. 9A. FIG. 10B is a cross section corresponding to the region ABS of FIG. 10A. In the step, first, a magnetic layer 162 P is formed on the magnetic layer 161 P. The magnetic layer 162 P is formed by frame plating, for example. In this case, the magnetic layer 161 P is used as an electrode for plating. In FIG. 9A, FIG. 10A and FIG. 10B, numeral 163 indicates an unwanted plating layer formed outside the frame. Next, the layered structure made up of the magnetic layer 161 P and the polishing stopper layer 13 except portions below the magnetic layer 162 P and the plating layer 163 is removed by etching.
FIG. 11A, FIG. 11B, FIG. 12A and FIG. 12B illustrate the following step. FIG. 11A shows the top surface of the layered structure in the course of manufacturing process of the magnetic head. FIG. 11B illustrates a cross section of the layered structure orthogonal to the medium facing surface and the substrate. FIG. 11B is a cross section taken along line B-B of FIG. 11A. FIG. 12A is an enlarged view of neighborhood of the region ABS of FIG. 11A. FIG. 12B is a cross section corresponding to the region ABS of FIG. 12A. In the step, first, a coating layer 32 made of alumina, for example, and having a thickness of 1.0 to 1.5 μm, for example, is formed on the entire top surface of the layered structure. Next, the coating layer 32 , the magnetic layer 162 P and the magnetic layer 161 P are polished by CMP, for example, until the polishing stopper layer 13 is exposed, and the top surfaces of the polishing stopper layer 13 , the magnetic layer 161 P and the magnetic layer 162 P are thereby flattened. As a result, portions of the magnetic layers 161 P and 162 P disposed on the top surface of the polishing stopper layer 13 are removed. The remaining portions of the magnetic layers 161 P and 162 P are hereinafter called magnetic layers 161 Q and 162 Q, respectively. A combination of the magnetic layers 161 Q and 162 Q is called a magnetic layer 160 .
If the coating layer 32 , the magnetic layer 162 P and the magnetic layer 161 P are polished by CMP, such a slurry is used that polishing is stopped when the polishing stopper layer 13 is exposed, such as an alumina-base slurry. It is possible to control the thickness of the magnetic layer 160 that will be the pole layer 16 later with accuracy by stopping the polishing when the polishing stopper layer 13 is exposed as thus described.
As shown in FIG. 11A and FIG. 12A, the magnetic layer 160 incorporates a portion 160 a corresponding to the pole layer, indicator portions 160 b and 160 c , and a coupling portion 160 d . The portion 160 a is a portion to be the pole layer 16 later, and this is a portion of the magnetic layer 160 shown on a right side of the region ABS in FIG. 11A and shown above the region ABS in FIG. 12A. The indicator portions 160 b and 160 c correspond to the indicators of the invention, and each serve as a reference for indicating the location of the region ABS. Each of the indicator portions 160 b and 160 c has a plane geometry that is rectangle-shaped. The coupling portion 160 d is a portion for coupling the portion 160 a and the indicator portions 160 b , 160 c of the magnetic layer 160 to each other.
As shown in FIG. 1, the plane geometries of the portion 160 a , the indicator portions 160 b and 160 c , and the coupling portion 160 d are the same as the geometries of the portion 120 a , the indicator portions 120 b and 120 c , and the coupling portion 120 d , respectively, in the top surface of the encasing layer 12 . The portion 160 a includes the track width defining portion 16 A and the wide portion 16 B. The indicator portion 160 b has two ends 160 b 1 and 160 b 2 each of which is parallel to the region ABS. Similarly, the indicator portion 160 c has two ends 160 c 1 and 160 c 2 each of which is parallel to the region ABS. The ends 160 b 1 and 160 c 1 are located closer to the region ABS than the ends 160 b 2 and 160 c 2 . The distance between the region ABS and the end 160 b 1 is equal to the distance between the region ABS and the end 160 c 1 . Similarly, the distance between the region ABS and the end 160 b 2 is equal to the distance between the region ABS and the end 160 c 2 . In the embodiment, the location of the ends 160 b 1 and 160 c 1 serves as a reference for indicating the location of the region ABS, as the location of the ends 120 b 1 and 120 c 1 . The distance between the region ABS and the ends 160 b 1 , 160 c 1 is equal to the distance D 1 between the region ABS and the ends 120 b 1 , 120 c 1 . The distance D 1 is designed to be of a specific value. Furthermore, the distance between each of the indicator portions 160 b , 160 c and the track width defining portion 16 A taken in the direction of width thereof is defined as D 3 . The preferred ranges of the distances D 1 and D 3 are described above.
The method of obtaining the location of the region ABS and the track width by observing the opening 13 a of the polishing stopper layer 13 through the use of an electron microscope is described above. In a similar manner, it is possible to obtain the location of the region ABS and the track width by observing the magnetic layer 160 through the use of an electron microscope. That is, as described above, the location of the ends 160 b 1 and 160 c 1 serves as the reference for indicating the location of the region ABS. Therefore, it is possible to obtain the location of the region ABS by observing the magnetic layer 160 and measuring the location of the ends 160 b 1 and 160 c 1 . It is further possible to obtain the track width by measuring the width of the magnetic layer 160 at the location of the region ABS. If the distance D 1 between the region ABS and the ends 160 b 1 , 160 c 1 is other than zero, the region ABS is placed in a location away from the ends 160 b 1 and 160 c 1 by the distance D 1 . If the distance D 1 is zero, the location of the region ABS is the location of the ends 160 b 1 and 160 c 1 . The magnetic layer 160 is conductive. Therefore, it is possible to obtain a correct image of the magnetic layer 160 by an electron microscope.
The indicator portions 160 b and 160 c are located at a height the same as the portion 160 a corresponding to the pole layer in a neighborhood of the region in which the track width defining portion 16 A is located. Therefore, it is possible to determine the location of the region ABS and to obtain the track width through a single observation using an electron microscope.
The indicator portions 160 b and 160 c are disposed on both sides of the track width defining portion 16 A, the sides being opposed to each other in the direction of width of the defining portion 16 A. In addition, the distance between the region ABS and the end 160 b 1 is equal to the distance between the region ABS and the end 160 c 1 . Therefore, the region ABS is parallel to an imaginary straight line that is in contact with the ends 160 b 1 and 160 c 1 . Based on the foregoing findings of the embodiment, it is possible to obtain the location of the region ABS with higher accuracy, referring to the two indicator portions 160 b and 160 c.
According to the embodiment, each of the pole layer 16 and the indicator portions 160 b and 160 c that are made up of portions of the magnetic layer 160 is conductive. In addition, the indicator portions 160 b and 160 c are electrically connected to the pole layer 16 . Therefore, when the indicator portions 160 b and 160 c are observed by an electron microscope, it is possible to prevent electric charges from accumulating on the indicator portions 160 b and 160 c . In addition, the potential of the indicator portions 160 b and 160 c is the same as that of the pole layer 16 , and it is thereby possible to obtain correct images of the indicator portions 160 b and 160 c together with the pole layer 16 . It is thereby possible to obtain the location of the region ABS with higher accuracy.
FIG. 13A and FIG. 13B illustrate the following step. FIG. 13A shows a cross section of the layered structure in the course of manufacturing process of the magnetic head, the cross section being orthogonal to the medium facing surface and the substrate. FIG. 13B is an enlarged view of cross section corresponding to the region ABS of FIG. 13A. In the step, a portion of the polishing stopper layer 13 located outside the coating layer 32 is removed by etching.
FIG. 14A and FIG. 14B illustrate the following step. FIG. 14A shows a cross section of the layered structure in the course of manufacturing process of the magnetic head, the cross section being orthogonal to the medium facing surface and the substrate. FIG. 14B is an enlarged view of cross section corresponding to the region ABS of FIG. 14A. In the step, first, the gap layer 18 is formed on the entire top surface of the layered structure. Next, a region of the gap layer 18 in which the yoke layer 20 B is to be formed is selectively etched to form an opening in the gap layer 18 . Next, the first layer 20 A is formed on the gap layer 18 , and the yoke layer 20 B is formed on a portion of the magnetic layer 160 where the opening of the gap layer 18 is formed. The first layer 20 A and the yoke layer 20 B may be formed by frame plating or by making a magnetic layer through sputtering and then selectively etching the magnetic layer. A method of selectively etching the magnetic layer may be, for example, forming an alumina layer on the magnetic layer, forming a mask on the alumina layer by frame plating, and etching the alumina layer and the magnetic layer using the mask. Next, the nonmagnetic layer 21 is formed on the entire top surface of the layered structure.
FIG. 15A and FIG. 15B illustrate the following step. FIG. 15A shows a cross section of the layered structure in the course of manufacturing process of the magnetic head, the cross section being orthogonal to the medium facing surface and the substrate. FIG. 15B is an enlarged view of cross section corresponding to the region ABS of FIG. 15A. In the step, first, the nonmagnetic layer 21 is polished by CMP, for example, so that the first layer 20 A and the yoke layer 20 B are exposed, and the top surfaces of the first layer 20 A, the yoke layer 20 B and the nonmagnetic layer 21 are flattened. Next, the insulating layer 22 having a thickness that falls within a range of 0.2 to 0.3 μm inclusive, for example, is formed by a method such as sputtering on the entire top surface of the layered structure. Next, the insulating layer 22 except a portion on which the coil 23 and the insulating layer 24 will be disposed later is removed by etching. Next, the coil 23 is formed by frame plating, for example, on the insulating layer 22 . Next, the second layer 20 C and the coupling layer 20 D are formed by frame plating, for example. Alternatively, the coil 23 may be formed after the second layer 20 C and the coupling layer 20 D are formed.
FIG. 16A and FIG. 16B illustrate the following step. FIG. 16A shows a cross section of the layered structure in the course of manufacturing process of the magnetic head, the cross section being orthogonal to the medium facing surface and the substrate. FIG. 16B is an enlarged view of cross section corresponding to the region ABS of FIG. 16A. In the step, first, the insulating layer 24 made of photoresist, for example, is selectively formed in the space between adjacent ones of the turns of the coil 23 and around the coil 23 . Next, an insulating layer not shown having a thickness of 4 to 4.5 μm, for example, is formed on the entire top surface of the layered structure. Next, the insulating layer is polished by CMP, for example, so that the second layer 20 C, the coupling layer 20 D and the coil 23 are exposed, and the top surfaces of the second layer 20 C, the coupling layer 20 D, the coil 23 and the insulating layer 24 are thereby flattened. Next, the insulating layer 25 is formed on the coil 23 and the insulating layer 24 . Next, the third layer 20 E is formed by frame plating, for example, to complete the shield layer 20 .
Next, although not shown, a protection layer is formed to cover the entire top surface of the layered structure. Wiring and terminals are then formed on the protection layer. In such a manner, components of a plurality of magnetic heads including a plurality of sets of pole layer 16 and coil 23 are formed in the single substrate 1 . The magnetic head substructure is thus fabricated in which a plurality of rows of pre-head portions that will be magnetic heads later are aligned. The magnetic head substructure is cut in a neighborhood of the region ABS. A surface formed by cutting the magnetic head substructure is polished to form the medium facing surfaces 30 . Furthermore, a plurality of pre-head portions are separated from one another by cutting the substructure, and a plurality of magnetic heads are thereby formed. When the pre-head portions are separated, the magnetic layers 161 Q and 162 Q become the first layer 161 and the second layer 162 , respectively.
Reference is now made to FIG. 17 to FIG. 19 to describe a specific example of the step of fabricating a plurality of magnetic heads by separating the magnetic head substructure. FIG. 17 is a top view of the magnetic head substructure. As shown in FIG. 17, the magnetic head substructure 210 includes a plurality of rows of pre-head portions 211 . In the step of fabricating the magnetic heads, first, the substructure 210 is cut in the positions indicated with dashed lines of FIG. 17 to form head aggregates 212 each of which includes a row of plurality of pre-head portions 211 . Next, a surface (the lower surface in FIG. 17) formed in each head aggregate 212 by cutting the substructure 210 is polished (lapped) to form the medium facing surfaces 30 of the pre-head portions 211 that the head aggregate 212 includes.
Reference is now made to FIG. 18 and FIG. 19 to describe a method of forming the medium facing surfaces 30 by lapping the head aggregate 212 . In this method, the head aggregate 212 is lapped so that the MR heights and the throat heights of the pre-head portions 211 are made equal while the resistances of the MR elements 5 that the head aggregate 212 includes are detected. The MR height is the length of each of the MR elements 5 taken in the direction orthogonal to the medium facing surface 30 .
FIG. 18 is a perspective view illustrating a schematic configuration of a lapping apparatus for lapping the head aggregate 212 . This lapping apparatus 251 comprises: a table 260 ; a rotating lapping table 261 provided on the table 260 ; a strut 262 provided on the table 260 on a side of the rotating lapping table 261 ; and a supporter 270 attached to the strut 262 through an arm 263 . The rotating lapping table 261 has a lapping plate (surface plate) 261 a to come to contact with the surface to be the medium facing surfaces 30 of the pre-head portions 211 that the head aggregate 212 includes.
The supporter 270 comprises a jig retainer 273 and three load application rods 275 A, 275 B and 275 C placed in front of the jig retainer 273 at equal spacings. A jig 280 is to be fixed to the jig retainer 273 . The jig 280 has three load application sections each of which is in the shape of a hole having an oblong cross section. Load application pins are provided at the lower ends of the load application rods 275 A, 275 B and 275 C, respectively. The load application pins have respective heads to be inserted to the load application sections (holes) of the jig 280 , the heads each having an oblong cross section. Each of the load application pins is driven by an actuator (not shown) in the vertical, horizontal (along the length of the jig 280 ) and rotational directions.
The jig 280 has a retainer for retaining the head aggregate 212 . With this jig 280 , the retainer and the head aggregate 212 are deformed by applying loads in various directions to the three load application sections. It is thereby possible that the surface to be the medium facing surfaces 30 of the pre-head portions 211 that the head aggregate 212 includes is lapped while the throat heights and MR heights of a plurality of pre-head portions 211 that the head aggregate 212 includes are controlled to be of target values.
FIG. 19 is a block diagram showing an example of circuit configuration of the lapping apparatus shown in FIG. 18. This lapping apparatus comprises: nine actuators 291 to 299 for applying loads in the three directions to the load application sections of the jig 280 ; a controller 286 for controlling the actuators 291 to 299 through monitoring the resistance values of a plurality of MR elements 5 in the head aggregate 212 ; and a multiplexer 287 , connected to the MR elements 5 in the head aggregate 212 through a connector (not shown), for selectively connecting one of the MR elements 5 to the controller 286 .
In this lapping apparatus, the controller 286 monitors the resistance values of the MR elements 5 in the head aggregate 212 through the multiplexer 287 , and controls the actuators 291 to 299 so that the throat height and the MR height of each of the pre-head portions 211 in the head aggregate 212 fall within a tolerance.
Flying rails are formed by etching, for example, in the medium facing surfaces 30 formed by lapping as described above. The head aggregate 212 is then cut so that the pre-head portions 211 are separated from one another, and a plurality of magnetic heads are thereby formed.
The specific details of the step of fabricating the magnetic heads by separating the magnetic head substructure are not limited to the example described with reference to FIG. 17 to FIG. 19. For example, the magnetic heads may be fabricated in the following manner. First, the magnetic head substructure 210 is cut to fabricate a first head aggregate that includes a plurality of rows of pre-head portions 211 . Next, a surface of the first head aggregate is lapped to form the medium facing surfaces 30 of a single row of pre-head portions 211 . Next, the first head aggregate is cut so that the single row of pre-head portions 211 in which the medium facing surfaces 30 have been formed is separated to be a second head aggregate. Next, the second head aggregate is cut so that the pre-head portions 211 are separated from one another, and a plurality of magnetic heads are thereby fabricated.
According to the method of manufacturing the magnetic head and the magnetic head substructure of the embodiment, a plurality of indicators ( 120 b , 120 c , 160 b and 160 c ) are formed in the substructure, wherein each of the indicators serves as a reference for indicating the location of the region ABS in which the medium facing surfaces 30 of the magnetic heads will be formed. As a result, it is possible in the course of manufacturing process of the magnetic heads to know the location of the region ABS in which the medium facing surfaces will be formed. It is thereby possible to obtain the track width with accuracy. Furthermore, it is thereby possible to improve the efficiency in manufacturing the magnetic heads.
According to the embodiment, the indicator portions 120 b and 120 c as portions of the groove 120 of the encasing layer 12 and the indicator portions 160 b and 160 c as portions of the magnetic layer 160 each function as the indicators. To determine the location of the region ABS and the track width in the course of manufacturing process of the magnetic heads, at least one of the indicator portions 120 b , 120 c and the indicator portions 160 b , 160 c may be observed.
In the example shown in FIG. 1, the indicator portions 120 b , 120 c , 160 b and 160 c are located in a region that will not remain in each magnetic head, that is, in a region lower than the region ABS. However, at least part of the ends of the indicator portions 120 b , 120 c , 160 b and 160 c may be located in a region that will remain in each magnetic head, that is, in a region higher than the region ABS of FIG. 1.
In the example shown in FIG. 1, the locations of the ends 120 b 1 , 120 c 1 , 160 b 1 and 160 c 1 are used as the reference for indicating the location of the region ABS. However, the locations of the ends 120 b 2 , 120 c 2 , 160 b 2 and 160 c 2 may be used as the reference for indicating the location of the region ABS.
According to the method of manufacturing the magnetic head and the magnetic head substructure of the embodiment, the polishing of the magnetic layers 161 P and 162 P is stopped when the polishing stopper layer 13 is exposed. The edge of the opening 13 a of the polishing stopper layer 13 is located directly above the edge of the groove 120 located in the top surface of the encasing layer 12 . Therefore, a difference in level is hardly created between the top surface of the polishing stopper layer 13 and the top surfaces of the magnetic layers 161 P and 162 P when the polishing of the magnetic layers 161 P and 162 P is stopped. As a result, according to the embodiment, it is possible to control the thickness of the pole layer 16 with accuracy. Furthermore, it is thereby possible to control the width of the top surface of the pole layer 16 with accuracy. As a result, it is possible to control the track width with accuracy. According to the embodiment, the side portions of the pole layer 16 are not etched. As a result, it is impossible that the neck height NH is made greater than a desired value and/or the pole layer 16 goes out of a desired shape. It is therefore possible to improve the overwrite property. Because of the foregoing features of the embodiment, it is possible to form the pole layer 16 with accuracy that has a small width and a shape capable of preventing the problems resulting from the skew.
In the embodiment, after the coating layer 32 and the magnetic layers 161 P and 162 P are polished until the polishing stopper layer 13 is exposed, the polishing stopper layer 13 may be selectively removed by reactive ion etching or ion beam etching, for example. Furthermore, the magnetic layers 161 P and 162 P may be slightly polished by CMP, for example, to flatten the top surfaces of the encasing layer 12 and the magnetic layers 161 P and 162 P. Alternatively, after the coating layer 32 and the magnetic layers 161 P and 162 P are polished until the polishing stopper layer 13 is exposed, ion beam etching may be performed to remove the polishing stopper layer 13 and to etch portions of the magnetic layers 161 P and 162 P, so that the top surfaces of the encasing layer 12 and the magnetic layers 161 P and 162 P are flattened.
FIG. 20A and FIG. 20B illustrate a modification example of the method of manufacturing the magnetic head and the magnetic head substructure of the embodiment. FIG. 20A illustrates a cross section of the layered structure in the course of manufacturing process of the magnetic head, the cross section being orthogonal to the medium facing surface and the substrate. FIG. 20B is an enlarged view of a cross section corresponding to the region ABS of FIG. 20A. In FIG. 20A and FIG. 20B, the portion closer to the substrate 1 than the encasing layer 12 is omitted.
The magnetic head of the modification example comprises an insulating layer 26 covering at least part of the coil 23 in place of the insulating layers 24 and 25 of FIG. 3. The shield layer 20 of the modification example comprises a second layer 20 F in place of the second layer 20 C, the coupling layer 20 D and the third layer 20 E of FIG. 3. The second layer 20 F has an end located in the medium facing surface 30 , and is disposed to couple the first layer 20 A to the yoke layer 20 B. The second layer 20 F includes a portion located on a side of the at least part of the coil 23 covered with the insulating layer 26 , the side being opposite to the pole layer 16 . The second layer 20 F includes a portion located between the medium facing surface 30 and the coil 23 . In this portion, the distance between the end located in the medium facing surface 30 and the other end increases as the distance from the first layer 20 A increases. The second layer 20 F is made of CoNiFe or NiFe, for example. The remainder of configuration of the magnetic head of the modification example is the same as that of the magnetic head shown in FIG. 2 and FIG. 3.
A method of manufacturing the magnetic head of the modification example includes the steps up to the step of forming the coil 23 that are the same as those of the method of manufacturing the magnetic head shown in FIG. 2 and FIG. 3. In the modification example, after the coil 23 is formed, the insulating layer 26 and the second layer 20 F are formed one by one. The following steps of the method of manufacturing the magnetic head of the modification example are the same as those of the method of manufacturing the magnetic head shown in FIG. 2