Butterfield, Paul D. (San Jose, CA, US)
Chen, Liang-yuh (Foster City, CA, US)
Hu, Yonqi (San Jose, CA, US)
Manens, Antoine P. (Palo Alto, CA, US)
Mavliev, Rashid (Campbell, NC, US)
Tsai, Stan D. (Fremont, CA, US)
Liu, Feng Q. (San Jose, CA, US)
Wadensweiler, Ralph (Sunnyvale, CA, US)
Sun, Lizhong (Sunnyvale, CA, US)
Neo, Siew S. (Santa Clara, CA, US)
Duboust, Alain (Sunnyvale, CA, US)

Plaque It!

11/868829

09/09/2008

10/08/2007

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Applied Materials, Inc. (Santa Clara, CA, US)

451/533

451/527

B24D11/02; B23H5/06; C25D5/22

451/526-539, 204/224M, 205/663

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Thomas, David B.

Patterson & Sheridan

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 11/215,254, filed Aug. 30, 2005 (hereinafter referred to as the “'254 application”) now U.S. Pat. No. 7,278,911, which is a continuation of U.S. patent application Ser. No. 10/642,128, filed Aug. 15, 2003 and issued as U.S. Pat. No. 6,962,524 on Nov. 8, 2005 (hereinafter referred to as the “'524 patent”). The '254 application is also a continuation-in-part of U.S. patent application Ser. No. 10/608,513, filed Jun. 26, 2003 now U.S. Pat. No. 7,374,644, and published as U.S. Patent publication No. 2004/0134792, (hereinafter referred to as the “'513 application”), which is a continuation-in-part of U.S. patent application Ser. No. 10/140,010, filed May 7, 2002 and issued as U.S. Pat. No. 6,979,248 on Dec. 27, 2005. The '513 application is also a continuation-in-part of U.S. patent application Ser. No. 10/211,626, filed Aug. 2, 2002 and issued as U.S. Pat. No. 7,125,477 on Oct. 24, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 10/033,732, filed Dec. 27, 2001 and issued as U.S. Pat. No. 7,066,800 on Jun. 27, 2006, which is a continuation-in-part of U.S. patent application Ser. No. 09/505,899, filed Feb. 17, 2000 and issued as U.S. Pat. No. 6,537,144 on Mar. 25, 2003. The '513 application is additionally a continuation-in-part of U.S. patent application Ser. No. 10/210,972, filed Aug. 2, 2002 now U.S. Pat. No. 7,303,662 and published as U.S. Patent publication No. 2004/0020788 on Feb. 5, 2004, which is also a continuation-in-part of U.S. patent application Ser. No. 09/505,899, filed Feb. 17, 2000 now U.S. Pat. No. 6,537,144. The '513 application is further continuation-in-part of U.S. patent application Ser. No. 10/151,538, filed May 16, 2002 now abandoned, which published as U.S. Patent publication No. 2003/0213703 on Nov. 20, 2003. The '524 patent is also a continuation-in-part of U.S. patent application Ser. No. 10/244,697, filed Sep. 16, 2002 and issued as U.S. Pat. No. 6,991,526 on Jan. 31, 2006, a continuation-in-part of U.S. application Ser. No. 10/244,688, filed Sep. 16, 2002 and issued as U.S. Pat. No. 6,848,970 on Feb. 1, 2005, and a continuation-in-part of U.S. patent application Ser. No. 10/391,324, filed Mar. 18, 2003 now abandoned and published as U.S. Patent publication No. 2004/0182721 on Sep. 23, 2004. All of the above referenced applications are hereby incorporated by reference in their entireties.

What is claimed is:

1. A polishing article for polishing a substrate, comprising: an upper layer having a polishing surface made of a dielectric material that is disposed on a subpad; a conductive layer disposed on the subpad opposite the upper layer; and a plurality of concentric apertures formed through the upper layer and the subpad exposing the conductive layer, wherein each of the upper layer, the subpad, and the conductive layer define a central opening adapted to receive at least one conductive contact element.

2. The polishing article of claim 1, wherein the subpad has a hardness between about 20 Shore A and about 90 Shore A.

3. The polishing article of claim 1, wherein the conductive layer is fabricated from stainless steel.

4. The polishing article of claim 1, wherein the conductive layer further comprises a plurality of independently biasable electrical zones.

5. The polishing article of claim 4, wherein the electrical zones further comprise concentric rings.

6. The polishing article of claim 1, wherein the subpad comprises at least one of polyurethane, polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylene polymers, compressed felt fibers impregnated with urethane, or combinations thereof.

7. The polishing article of claim 6, wherein the conductive layer comprises stainless steel.

8. The polishing article of claim 1, wherein the upper layer comprises a polyurethane material and the conductive layer comprises stainless steel.

9. The polishing article of claim 1, wherein the subpad, the conductive layer and the upper layer are coupled by at least one of compression molding, staking, fastening, adhering and bonding.

10. A polishing article for polishing a substrate, comprising: an upper layer having a polishing surface made of a dielectric polymer material; a conductive metal layer comprising a plurality of independently biasable electrical zones; a subpad disposed between the conductive metal layer and the upper layer, the subpad comprising a material selected from polyurethane, polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylene polymers, compressed felt fibers impregnated with urethane, or combinations thereof; and a plurality of concentrically aligned apertures formed through the upper layer and the subpad to expose the conductive metal layer, wherein each of the upper layer, the subpad, and the conductive layer define a central opening adapted to receive a housing having conductive contact elements disposed therein.

11. The polishing article of claim 10, wherein the subpad, the conductive metal layer and the upper layer are coupled by at least one of compression molding, staking, fastening, adhering and bonding.

12. The polishing article of claim 10, wherein the electrical zones further comprise concentric rings.

13. The polishing article of claim 10, wherein the conductive metal layer further comprises at least one insulating spacer separating the zones.

14. The polishing article of claim 10, wherein the electrical zones further comprise concentric rings separated by at least one insulating spacer.

15. The polishing article of claim 10, wherein the electrical zones further comprise concentric rings separated by a gap.

16. A polishing article for polishing a substrate, comprising: an upper layer having a grooved polishing surface comprising polyurethane; a conductive metal layer comprising a plurality of independently biasable concentric rings adapted to be disposed on a platen; a subpad disposed between the conductive metal layer and the upper layer, the subpad comprising a material selected from polyurethane, polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylene polymers, compressed felt fibers impregnated with urethane, or combinations thereof; and a plurality of concentrically aligned apertures formed through the upper layer and the subpad to expose the conductive metal layer, wherein the upper layer, the subpad, and the conductive metal layer are coupled by at least one of compression molding, staking, fastening, adhering and bonding and each define a central opening therethrough.

17. The polishing article of claim 16, wherein the concentric rings are separated by at least one insulating spacer.

18. The polishing article of claim 16, wherein the concentric rings are separated by a gap.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an article of manufacture and apparatus for planarizing a substrate surface.

2. Background of the Related Art

Sub-quarter micron multi-level metallization is one of the key technologies for the next generation of ultra large-scale integration (ULSI). The multilevel interconnects that lie at the heart of this technology require planarization of interconnect features formed in high aspect ratio apertures, including contacts, vias, lines and other features. Reliable formation of these interconnect features is very important to the success of ULSI and to the continued effort to increase circuit density and quality on individual substrates and die.

In the fabrication of integrated circuits and other electronic devices, multiple layers of conducting, semiconducting, and dielectric materials are deposited on or removed from a surface of a substrate. Thin layers of conducting, semiconducting, and dielectric materials may be deposited by a number of deposition techniques. Common deposition techniques in modern processing include physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), and electro-chemical plating (ECP).

As layers of materials are sequentially deposited and removed, the uppermost surface of the substrate may become non-planar across its surface and require planarization. Planarizing a surface, or “polishing” a surface, is a process where material is removed from the surface of the substrate to form a generally even, planar surface. Planarization is useful in removing undesired surface topography and surface defects, such as rough surfaces, agglomerated materials, crystal lattice damage, scratches, and contaminated layers or materials. Planarization is also useful in forming features on a substrate by removing excess deposited material used to fill the features and to provide an even surface for subsequent levels of metallization and processing.

Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize substrates. CMP utilizes a chemical composition, typically a slurry or other fluid medium, for selective removal of material from substrates. In conventional CMP techniques, a substrate carrier or polishing head is mounted on a carrier assembly and positioned in contact with a polishing pad in a CMP apparatus. The carrier assembly provides a controllable pressure to the substrate urging the substrate against the polishing pad. The pad is moved relative to the substrate by an external driving force. The CMP apparatus effects polishing or rubbing movement between the surface of the substrate and the polishing pad while dispersing a polishing composition to effect chemical activity and/or mechanical activity and consequential removal of material from the surface of the substrate.

One material increasingly utilized in integrated circuit fabrication is copper due to its desirable electrical properties. However, copper has its own special fabrication problems. For example, copper is difficult to pattern and etch and new processes and techniques, such as damascene or dual damascene processes, are being used to form copper substrate features.

In damascene processes, a feature is defined in a dielectric material and subsequently filled with copper. Dielectric materials with low dielectric constants, i.e., less than about 3, are being used in the manufacture of copper damascenes. Barrier layer materials are deposited conformally on the surfaces of the features formed in the dielectric layer prior to deposition of copper material. Copper material is then deposited over the barrier layer and the surrounding field. However, copper fill of the features usually results in excess copper material, or overburden, on the substrate surface that must be removed to form a copper filled feature in the dielectric material and prepare the substrate surface for subsequent processing.

One challenge that is presented in polishing copper materials is that the interface between the conductive material and the barrier layer is generally non-planar and residual copper material is retained in irregularities formed by the non-planar interface. Further, the conductive material and the barrier materials are often removed from the substrate surface at different rates, both of which can result in excess conductive material being retained as residues on the substrate surface. Additionally, the substrate surface may have different surface topography, depending on the density or size of features formed therein. Copper material is removed at different removal rates along the different surface topography of the substrate surface, which makes effective removal of copper material from the substrate surface and final planarity of the substrate surface difficult to achieve.

One solution to remove all of the desired copper material from the substrate surface is to overpolish the substrate surface. However, overpolishing of some materials can result in the formation of topographical defects, such as concavities or depressions in features, referred to as dishing, or excessive removal of dielectric material, referred to as erosion. The topographical defects from dishing and erosion can further lead to non-uniform removal of additional materials, such as barrier layer materials disposed thereunder, and produce a substrate surface having a less than desirable polishing quality.

Another problem with the polishing of copper surfaces arises from the use of low dielectric constant (low k) dielectric materials to form copper damascenes in the substrate surface. Low k dielectric materials, such as carbon doped silicon oxides, may deform or fracture under conventional polishing pressures (i.e., about 6 psi), called downforce, which can detrimentally affect substrate polish quality and detrimentally affect device formation. For example, relative rotational movement between the substrate and a polishing pad can induce a shear force along the substrate surface and deform the low k material to form topographical defects, which can detrimentally affect subsequent polishing.

One solution for polishing copper in low dielectric materials is by polishing copper by electrochemical mechanical polishing (ECMP) techniques. ECMP techniques remove conductive material from a substrate surface by electrochemical dissolution while concurrently polishing the substrate with reduced mechanical abrasion compared to conventional CMP processes. The electrochemical dissolution is performed by applying a bias between a cathode and substrate surface to remove conductive materials from a substrate surface into a surrounding electrolyte.

In one embodiment of an ECMP system, the bias is applied by a ring of conductive contacts in electrical communication with the substrate surface in a substrate support device, such as a substrate carrier head. However, the contact ring has been observed to exhibit non-uniform distribution of current over the substrate surface, which results in non-uniform dissolution, especially during overpolishing where a ring of conductive contacts doesn't efficiently remove residues. Mechanical abrasion is performed by contacting the substrate with a conventional polishing pad and providing relative motion between the substrate and polishing pad. However, conventional polishing pads often limit electrolyte flow to the surface of the substrate. Additionally, the polishing pad may be composed of insulative materials that may interfere with the application of bias to the substrate surface and result in non-uniform or variable dissolution of material from the substrate surface.

As a result, there is a need for an improved polishing article for the removal of conductive material on a substrate surface.

SUMMARY OF THE INVENTION

Aspects of the invention generally provide an article of manufacture and an apparatus for planarizing a layer on a substrate using electrochemical dissolution techniques, polishing techniques, and/or combinations thereof.

In one aspect, polishing article for polishing a substrate comprises an upper layer having a polishing surface made of a dielectric material that is disposed on a subpad, a conductive layer disposed on the subpad opposite the upper layer, and a plurality of concentric apertures formed through the upper layer and the subpad exposing the conductive layer, wherein each of the upper layer, the subpad, and the conductive layer define a central opening adapted to receive at least one conductive contact element.

In another aspect, polishing article for polishing a substrate comprises an upper layer having a polishing surface made of a dielectric polymer material, a conductive metal layer comprising a plurality of independently biasable electrical zones, a subpad disposed between the conductive metal layer and the upper layer, the subpad comprising a material selected from the group of polyurethane, polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylene polymers, compressed felt fibers impregnated with urethane, or combinations thereof, and a plurality of concentrically aligned apertures formed through the upper layer and the subpad to expose the conductive metal layer, wherein each of the upper layer, the subpad, and the conductive layer define a central opening adapted to receive a housing having conductive contact elements disposed therein.

In another aspect, a polishing article for polishing a substrate comprises an upper layer having a grooved polishing surface comprising polyurethane, a stainless steel layer comprising a plurality of independently biasable concentric rings adapted to be disposed on a platen, a subpad disposed between the conductive metal layer and the upper layer, the subpad comprising a material selected from the group of polyurethane, polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylene polymers, compressed felt fibers impregnated with urethane, or combinations thereof, and a plurality of concentrically aligned apertures formed through the upper layer and the subpad to expose the conductive metal layer, wherein the upper layer, the subpad, and the conductive layer are coupled by at least one of compression molding, staking, fastening, adhering and bonding and each define a central opening therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited aspects of the invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments thereof which are illustrated in the appended drawings.

It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and, therefore, are not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.

FIG. 1 is a plan view of one embodiment of a processing apparatus of the invention;

FIG. 2 is a sectional view of one embodiment of an ECMP station;

FIG. 3 is a partial cross-sectional view of one embodiment of a polishing article;

FIG. 4 is a top plan view of one embodiment of a grooved polishing article;

FIGS. 5-6 are top plan views of embodiments of a grooved polishing article;

FIG. 7A is a top view of a conductive cloth or fabric described herein;

FIGS. 7B and 7C are partial cross-sectional views of polishing articles having a polishing surface comprising a conductive cloth or fabric;

FIG. 7D is a partial cross-sectional view of one embodiment of a polishing article including a metal foil;

FIG. 7E is another embodiment of a polish article comprising a fabric material;

FIG. 7F is another embodiment of a polish article having a window formed therein;

FIGS. 8A and 8B are top and cross-section schematic views, respectively, of one embodiment of a polishing article having a conductive element;

FIGS. 8C and 8D are top and cross-section schematic views, respectively, of one embodiment of a polishing article having a conductive element;

FIGS. 9A and 9B are perspective views of other embodiments of a polishing article having a conductive element;

FIG. 10A is a partial perspective view of another embodiment of a polishing article;

FIG. 10B is a partial perspective view of another embodiment of a polishing article;

FIG. 10C is a partial perspective view of another embodiment of a polishing article;

FIG. 10D is a partial perspective view of another embodiment of a polishing article;

FIG. 10E is a partial perspective view of another embodiment of a polishing article;

FIGS. 11A-11C are schematic side views of one embodiment of a substrate contacting one embodiment of a polishing article described herein;

FIGS. 12A-12D are top and side schematic views of embodiments of a polishing article having extensions connected to a power source;

FIGS. 12E and 12F show side schematic and exploded perspective views of another embodiment of providing power to a polishing article;

FIGS. 13A-B are top and sectional views of another embodiment of a conductive article;

FIGS. 14A-D are top and sectional views of another embodiment of a conductive article;

FIGS. 15-17 are a sectional view of alternate embodiments of a conductive article;

FIG. 18 is sectional view of another embodiment of a conductive article having one embodiment of a ball assembly;

FIGS. 19A-B are side and exploded views of the ball assembly of FIG. 18;

FIG. 20 is one embodiment of a contact element of the ball assembly of FIGS. 18 and 19 A-B;

FIGS. 21-23 are perspective and sectional views of another embodiment of a conductive article having another embodiment of a ball assembly; and

FIGS. 24A-B are bottom views of alternate embodiments of an electrode that may advantageously adapted for use with different embodiments of conductive articles.

To facilitate understanding, identical reference numerals have been used, wherever possible, to designate identical elements that are common to the figures.

DETAILED DESCRIPTION

The words and phrases used herein should be given their ordinary and customary meaning in the art by one skilled in the art unless otherwise further defined. Chemical-mechanical polishing should be broadly construed and includes, but is not limited to, abrading a substrate surface by chemical activity, mechanical activity, or a combination of both chemical and mechanical activity. Electropolishing should be broadly construed and includes, but is not limited to, planarizing a substrate by the application of electrochemical activity, such as by anodic dissolution.

Electrochemical mechanical polishing (ECMP) should be broadly construed and includes, but is not limited to, planarizing a substrate by the application of electrochemical activity, chemical activity, mechanical activity, or a combination of electrochemical, chemical, and mechanical activity to remove material from a substrate surface.

Electrochemical mechanical plating process (ECMPP) should be broadly construed and includes, but is not limited to, electrochemically depositing material on a substrate and generally planarizing the deposited material by the application of electrochemical activity, chemical activity, mechanical activity, or a combination of electrochemical, chemical, and mechanical activity.

Anodic dissolution should be broadly construed and includes, but is not limited to, the application of an anodic bias to a substrate directly or indirectly which results in the removal of conductive material from a substrate surface and into a surrounding electrolyte solution. Polishing surface is broadly defined as the portion of an article of manufacture that at least partially contacts a substrate surface during processing or electrically couples an article of manufacture to a substrate surface either directly through contact or indirectly through an electrically conductive medium.

Polishing Apparatus

FIG. 1 depicts a processing apparatus 100 having at least one station suitable for electrochemical deposition and chemical mechanical polishing, such as electrochemical mechanical polishing (ECMP) station 102 and at least one conventional polishing or buffing station 106 disposed on a single platform or tool. One polishing tool that may be adapted to benefit from the invention is a MIRRA® Mesa™ chemical mechanical polisher available from Applied Materials, Inc. located in Santa Clara, Calif.

For example, in the apparatus 100 shown in FIG. 1, the apparatus 100 includes two ECMP stations 102 and one polishing station 106 . The stations may be used for processing a substrate surface. For example, a substrate having feature definitions formed therein and filled with a barrier layer and then a conductive material disposed over the barrier layer may have the conducive material removed in two steps in the two ECMP stations 102 with the barrier layer polished in the polishing station 106 to form a planarized surface.

The exemplary apparatus 100 generally includes a base 108 that supports one or more ECMP stations 102 , one or more polishing stations 106 , a transfer station 110 and a carousel 112 . The transfer station 110 generally facilitates transfer of substrates 114 to and from the apparatus 100 via a loading robot 116 . The loading robot 116 typically transfers substrates 114 between the transfer station 110 and a factory interface 120 that may include a cleaning module 122 , a metrology device 104 and one or more substrate storage cassettes 118 . One example of a metrology device 104 is a NovaScan™ Integrated Thickness Monitoring system, available from Nova Measuring Instruments, Inc., located in Phoenix, Ariz.

Alternatively, the loading robot 116 (or factory interface 120 ) may transfer substrates to one or more other processing tools (not shown) such as a chemical vapor deposition tool, physical vapor deposition tool, etch tool and the like.

In one embodiment, the transfer station 110 comprises at least an input buffer station 124 , an output buffer station 126 , a transfer robot 132 , and a load cup assembly 128 . The loading robot 116 places the substrate 114 onto the input buffer station 124 . The transfer robot 132 has two gripper assemblies, each having pneumatic gripper fingers that hold the substrate 114 by the substrate's edge. The transfer robot 132 lifts the substrate 114 from the input buffer station 124 and rotates the gripper and substrate 114 to position the substrate 114 over the load cup assembly 128 , then places the substrate 114 down onto the load cup assembly 128 .

The carousel 112 generally supports a plurality of polishing heads 130 , each of which retains one substrate 114 during processing. The carousel 112 transfers the polishing heads 130 between the transfer station 110 , the one or more ECMP stations 102 and the one or more polishing stations 106 . One carousel 112 that may be adapted to benefit from the invention is generally described in U.S. Pat. No. 5,804,507, issued Sep. 8, 1998 to Tolles et al., which is hereby incorporated by reference in its entirety.

Generally, the carousel 112 is centrally disposed on the base 108 . The carousel 112 typically includes a plurality of arms 138 . Each arm 138 generally supports one of the polishing heads 130 . One of the arms 138 depicted in FIG. 1 is not shown so that the transfer station 110 may be seen. The carousel 112 is indexable such that the polishing head 130 may be moved between the stations 102 , 106 and the transfer station 110 in a sequence defined by the user.

Generally the polishing head 130 retains the substrate 114 while the substrate 114 is disposed in the ECMP station 102 or polishing station 106 . The arrangement of the ECMP stations 106 and polishing stations 102 on the apparatus 100 allow for the substrate 114 to be sequentially plated or polished by moving the substrate between stations while being retained in the same polishing head 130 . One polishing head that may be adapted to the invention is a TITAN HEAD™ substrate carrier, manufactured by Applied Materials, Inc., located in Santa Clara, Calif.

Examples of embodiments of polishing heads 130 that may be used with the polishing apparatus 100 described herein are described in U.S. Pat. No. 6,183,354, issued Feb. 6, 2001 to Zuniga, et al., which is hereby incorporated by reference in its entirety.

To facilitate control of the polishing apparatus 100 and processes performed thereon, a controller 140 comprising a central processing unit (CPU) 142 , memory 144 , and support circuits 146 , is connected to the polishing apparatus 100 . The CPU 142 may be one of any form of computer processor that can be used in an industrial setting for controlling various drives and pressures. The memory 144 is connected to the CPU 142 . The memory 144 , or computer-readable medium, may be one or more of readily available memory such as random access memory (RAM), read only memory (ROM), floppy disk, hard disk, or any other form of digital storage, local or remote. The support circuits 146 are connected to the CPU 142 for supporting the processor in a conventional manner. These circuits include cache, power supplies, clock circuits, input/output circuitry, subsystems, and the like.

Power to operate the polishing apparatus 100 and/or the controller 140 is provided by a power supply 150 . Illustratively, the power supply 150 is shown connected to multiple components of the polishing apparatus 100 , including the transfer station 110 , the factory interface 120 , the loading robot 116 and the controller 140 . In other embodiments separate power supplies are provided for two or more components of the polishing apparatus 100 .

FIG. 2 depicts a sectional view of the polishing head 130 supported above an ECMP station 102 . The ECMP station 102 generally includes a basin 202 , an electrode 204 , polishing article 205 , a disc 206 and a cover 208 . In one embodiment, the basin 202 is coupled to the base 108 of the polishing apparatus 100 . The basin 202 generally defines a container or electrolyte cell in which a conductive fluid such as an electrolyte 220 can be confined. The electrolyte 220 used in processing the substrate 114 can be used to process metals such as copper, aluminum, tungsten, gold, silver, or any other materials that can be electrochemically deposited onto or electrochemically removed from the substrate 114 .

The basin 202 can be a bowl shaped member made of a plastic such as fluoropolymers, polytetrafluoroethylene, PFA, PE, PES, or other materials that are compatible with electroplating and electropolishing chemistries. The basin 202 has a bottom 210 that includes an aperture 216 and a drain 214 . The aperture 216 is generally disposed in the center of the bottom 210 and allows a shaft 212 to pass therethrough. A seal 218 is disposed between the aperture 216 and the shaft 212 and allows the shaft 212 to rotate while preventing fluids disposed in the basin 202 from passing through the aperture 216 .

The basin 202 typically includes the electrode 204 , the disc 206 , and the polishing article 205 disposed therein. Polishing article 205 , such as a polishing pad, is disposed and supported in the basin 202 on the disc 206 .

The electrode 204 is a counter-electrode to the substrate 114 and/or polishing article 205 contacting a substrate surface. The polishing article 205 is at least partially conductive and may act as an electrode in combination with the substrate during electrochemical processes, such as an electrochemical mechanical plating process (ECMPP), which includes electrochemical deposition and chemical mechanical polishing, or electrochemical dissolution. The electrode 204 may be an anode or cathode depending upon the positive bias (anode) or negative bias (cathode) applied between the electrode 204 and polishing article 405 .

For example, depositing material from an electrolyte on the substrate surface, the electrode 204 acts as an anode and the substrate surface and/or polishing article 205 acts as a cathode. When removing material from a substrate surface, such as by dissolution from an applied bias, the electrode 204 functions as a cathode and the substrate surface and/or polishing article 205 may act as an anode for the dissolution process.

The electrode 204 is generally positioned between the disc 206 and the bottom 210 of the basin 202 where it may be immersed in or exposed to the electrolyte 220 . The electrode 204 may be fabricated from a magnetically coupleable material to allow for the electrode to be secured to the platen. The electrode 204 can be a plate-like member, a plate having multiple apertures formed therethrough, or a plurality of electrode pieces disposed in a permeable membrane or container. A permeable membrane (not shown) may be disposed between the disc 206 and the electrode 204 or electrode 204 and polishing article 205 to filter bubbles, such as hydrogen bubbles, form the wafer surface and to reduce defect formation and stabilize or more uniformly apply current or power therebetween.

For electrodeposition processes, the electrode 204 is made of the material to be deposited or removed, such as copper, aluminum, gold, silver, tungsten and other materials which can be electrochemically deposited on the substrate 114 . For electrochemical removal processes, such as anodic dissolution, the electrode 204 may include a non-consumable electrode of a material other than the deposited material, for example, platinum, carbon, stainless steel, or aluminum, for copper dissolution.

The polishing article 205 can be a pad, a web or a belt of material, which is compatible with the fluid environment and the processing specifications. In the embodiment depicted in FIG. 2, the polishing article 205 is circular in form and positioned at an upper end of the basin 202 , supported on its lower surface by the disc 206 . The polishing article 205 includes at least a partially conductive surface of a conductive material, such as one or more conductive elements, for contact with the substrate surface during processing. The polishing article 205 may be a portion or all of a conductive polishing material or a composite of a conductive polishing material embedded in or disposed on a conventional polishing material. For example the conductive material may be disposed on a “backing” material disposed between the disc 206 and polishing article 205 to tailor the compliance and/or durometer of the polishing article 205 during processing.

The basin 202 , the cover 208 , and the disc 206 may be movably disposed on the base 108 . The basin 202 , cover 208 and disc 206 may be axially moved toward the base 108 to facilitate clearance of the polishing head 130 as the carousel 112 indexes the substrate 114 between the ECMP and polishing stations 102 , 106 . The disc 206 is disposed in the basin 202 and coupled to the shaft 212 . The shaft 212 is generally coupled to a motor 224 disposed below the base 108 . The motor 224 , in response to a signal from the controller 140 , rotates the disc 206 at a predetermined rate.

The disc 206 may be a perforated article support made from a material compatible with the electrolyte 220 which would not detrimentally affect polishing. The disc 206 may be fabricated from a polymer, for example fluoropolymers, PE, polytetrafluoroethylene, PFA, PES, HDPE, UHMW or the like. The disc 206 can be secured in the basin 202 using fasteners such as screws or other means such as snap or interference fit with the enclosure, being suspended therein and the like. The disc 206 is preferably spaced from the electrode 204 to provide a wider process window, thus reducing the sensitivity of depositing material and removing material from the substrate surface to the electrode 204 dimensions.

The disc 206 is generally permeable to the electrolyte 220 . In one embodiment, the disc 206 includes a plurality of perforations or channels 222 formed therein. Perforations include apertures, holes, openings, or passages formed partially or completely through an object, such as the polishing article. The perforation size and density is selected to provide uniform distribution of the electrolyte 220 through the disc 206 to the substrate 114 .

In one aspect of the disc 206 includes perforations having a diameter between about 0.02 inches (0.5 millimeters) and about 0.4 inches (10 mm). The perforations may have a perforation density between about 20% and about 80% of the polishing article. A perforation density of about 50% has been observed to provide electrolyte flow with minimal detrimental effects to polishing processes. Generally, the perforations of the disc 206 and the polishing article 205 are aligned to provide for sufficient mass flow of electrolyte through the disc 206 and polishing article 205 to the substrate surface. The polishing article 205 may be disposed on the disc 206 by a mechanical clamp or conductive adhesive.

While the polishing articles described herein for electrochemical-mechanical polishing (ECMP) processes, the invention contemplates using the conductive polishing article in other fabrication processes involving electrochemical activity. Examples of such processes using electrochemical activity include electrochemical deposition, which involves the polishing article 205 being used to apply an uniform bias to a substrate surface for depositing a conductive material without the use of conventional bias application apparatus, such as edge contacts, and electrochemical mechanical plating processes (ECMPP) that include a combination of electrochemical deposition and chemical mechanical polishing.

In operation, the polishing article 205 is disposed on the disc 206 in an electrolyte in the basin 202 . A substrate 114 on the polishing head is disposed in the electrolyte and contacted with the polishing article 205 . Electrolyte is flowed through the perforations of the disc 206 and the polishing article 205 and is distributed on the substrate surface by grooves formed therein. Power from a power source is then applied to the conductive polishing article 205 and the electrode 204 , and conductive material, such as copper, in the electrolyte is then removed by an anodic dissolution method.

The electrolyte 220 is flowed from a reservoir 233 into the volume 232 via a nozzle 270 . The electrolyte 220 is prevented from overflowing the volume 232 by a plurality of holes 234 disposed in a skirt 254 . The holes 234 generally provide a path through the cover 208 for the electrolyte 220 exiting the volume 232 and flowing into the lower portion of the basin 202 . At least a portion of the holes 234 are generally positioned between a lower surface 236 of the depression 258 and the center portion 252 . As the holes 234 are typically higher than the lower surface 236 of the depression 258 , the electrolyte 220 fills the volume 232 and is thus brought into contact with the substrate 114 and polishing medium 205 . Thus, the substrate 114 maintains contact with the electrolyte 220 through the complete range of relative spacing between the cover 208 and the disc 206 .

The electrolyte 220 collected in the basin 202 generally flows through the drain 214 disposed at the bottom 210 into the fluid delivery system 272 . The fluid delivery system 272 typically includes the reservoir 233 and a pump 242 . The electrolyte 220 flowing into the fluid delivery system 272 is collected in the reservoir 233 . The pump 242 transfers the electrolyte 220 from the reservoir 233 through a supply line 244 to the nozzle 270 where the electrolyte 220 recycled through the ECMP station 102 . A filter 240 is generally disposed between the reservoir 233 and the nozzle 270 to remove particles and agglomerated material that may be present in the electrolyte 220 .

Electrolyte solutions may include commercially available electrolytes. For example, in copper containing material removal, the electrolyte may include sulfuric acid based electrolytes or phosphoric acid based electrolytes, such as potassium phosphate (K ₃ PO ₄ ), or combinations thereof. The electrolyte may also contain derivatives of sulfuric acid based electrolytes, such as copper sulfate, and derivatives of phosphoric acid based electrolytes, such as copper phosphate. Electrolytes having perchloric acid-acetic acid solutions and derivatives thereof may also be used.

Additionally, the invention contemplates using electrolyte compositions conventionally used in electroplating or electropolishing processes, including conventionally used electroplating or electropolishing additives, such as brighteners among others. One source for electrolyte solutions used for electrochemical processes such as copper plating, copper anodic dissolution, or combinations thereof is Shipley Leonel, a division of Rohm and Haas, headquartered in Philadelphia, Pa., under the tradename Ultrafill 2000. An example of a suitable electrolyte composition is described in U.S. patent application Ser. No. 10/038,066, filed on Jan. 3, 2002, which is incorporated by reference in its entirety.

Electrolyte solutions are provided to the electrochemical cell to provide a dynamic flow rate on the substrate surface or between the substrate surface and an electrode at a flow rate up to about 20 gallons per minute (GPM), such as between about 0.5 GPM and about 20 GPM, for example, at about 2 GPM. It is believed that such flow rates of electrolyte evacuate polishing material and chemical by-products from the substrate surface and allow refreshing of electrolyte material for improved polishing rates.

When using mechanical abrasion in the polishing process, the substrate 114 and polishing article 205 are rotated relative to one another to remove material from the substrate surface. Mechanical abrasion may be provided by physical contact with both conductive polishing materials and conventional polishing materials as described herein. The substrate 114 and the polishing article 205 are respectively rotated at about 5 rpms or greater, such as between about 10 rpms and about 50 rpms.

In one embodiment, a high rotational speed polishing process may be used. The high rotational speed process includes rotating the polishing article 205 at a platen speed of about 150 rpm or greater, such as between about 150 rpm and about 750 rpm; and the substrate 114 may be rotated at a rotational speed between about 150 rpm and about 500 rpm, such as between about 300 rpm and about 500 rpm. Further description of a high rotational speed polishing process that may be used with the polishing articles, processes, and apparatus described herein is disclosed in U.S. Patent Application Ser. No. 60/308,030, filed on Jul. 25, 2001, and entitled, “Method And Apparatus For Chemical Mechanical Polishing Of Semiconductor Substrates.” Other motion, including orbital motion or a sweeping motion across the substrate surface, may also be performed during the process.

When contacting the substrate surface, a pressure of about 6 psi or less, such as about 2 psi or less is applied between the polishing article 205 and the substrate surface. If a substrate containing low dielectric constant material is being polished, a pressure between of about 2 psi or less, such as about 0.5 psi or less is used to press the substrate 114 against the polishing article 205 during polishing of the substrate. In one aspect, a pressure between about 0.1 psi and about 0.2 psi may be used to polishing substrates with conductive polishing articles as described herein.

In anodic dissolution, a potential difference or bias is applied between the electrode 204 , performing as a cathode, and the polishing surface 310 (See, FIG. 3) of the polishing article 205 , performing as the anode. The substrate in contact with the polishing article is polarized via the conductive polishing surface article 310 at the same time the bias is applied to the conductive article support member. The application of the bias allows removal of conductive material, such as copper-containing materials, formed on a substrate surface. Establishing the bias may include the application of a voltage of about 15 volts or less to the substrate surface. A voltage between about 0.1 volts and about 10 volts may be used to dissolve copper-containing material from the substrate surface and into the electrolyte. The bias may also produce a current density between about 0.1 milliamps/cm ² and about 50 milliamps/cm ² , or between about 0.1 amps to about 20 amps for a 200 mm substrate.

The signal provided by the power supply 150 to establish the potential difference and perform the anodic dissolution process may be varied depending upon the requirements for removing material from the substrate surface. For example, a time varying anodic signal may be provided to the conductive polishing medium 205 . The signal may also be applied by electrical pulse modulation techniques. The electrical pulse modification technique comprises applying a constant current density or voltage over the substrate for a first time period, then applying a constant reverse voltage or stopping applying a voltage over the substrate for a second time period, and repeating the first and second steps. For example, the electrical pulse modification technique may use a varying potential from between about −0.1 volts and about −15 volts to between about 0.1 volts and about 15 volts.

With the correct perforation pattern and density on the polishing media, it is believed that biasing the substrate from the polishing article 205 provides uniform dissolution of conductive materials, such as metals, into the electrolyte from the substrate surface as compared to the higher edge removal rate and lower center removal rate from conventional edge contact-pins bias.

Conductive material, such as copper containing material can be removed from at least a portion of the substrate surface at a rate of about 15,000 Å/min or less, such as between about 100 Å/min and about 15,000 Å/min. In one embodiment of the invention where the copper material to be removed is about 12,000 Å thick, the voltage may be applied to the conductive polishing article 205 to provide a removal rate between about 100 Å/min and about 8,000 Å/min.

Following the electropolishing process, the substrate may be further polished or buffed to remove barrier layer materials, remove surface defects from dielectric materials, or improve planarity of the polishing process using the conductive polishing article. An example of a suitable buffing process and composition is disclosed in co-pending U.S. patent application Ser. No. 09/569,968, filed on May 11, 2000, and incorporated herein by reference in its entirety.

Polishing Article Materials

The polishing articles described herein may be formed from conductive materials that may comprise a conductive polishing material or may comprise a conductive element disposed in a dielectric or conductive polishing material. In one embodiment, a conductive polishing material may include conductive fibers, conductive fillers, or combinations thereof. The conductive fibers, conductive fillers, or combinations thereof may be dispersed in a polymeric material.

The conductive fibers may comprise conductive or dielectric materials, such as dielectric or conductive polymers or carbon-based materials, at least partially coated or covered with a conductive material including a metal, a carbon-based material, a conductive ceramic material, a conductive alloy, or combinations thereof. The conductive fibers may be in the form of fibers or filaments, a conductive fabric or cloth, one or more loops, coils, or rings of conductive fibers. Multiple layers of conductive materials, for example, multiple layers of conductive cloth or fabric, may be used to form the conductive polishing material.

The conductive fibers include dielectric or conductive fiber materials coated with a conductive material. Dielectric polymeric materials may be used as fiber materials. Examples of suitable dielectric fiber materials include polymeric materials, such as polyamides, polyimides, nylon polymer, polyurethane, polyester, polypropylene, polyethylene, polystyrene, polycarbonate, diene containing polymers, such as AES (polyacrylontrile ethylene styrene), acrylic polymers, or combinations thereof. The invention also contemplates the use of organic or inorganic materials that may be used as fibers described herein.

The conductive fiber material may comprise intrinsically conductive polymeric materials including polyacetylene, polyethylenedioxythiophene (PEDT), which is commercially available under the trade name Baytron™, polyaniline, polypyrrole, polythiophene, carbon-based fibers, or combinations thereof. Another example of a conductive polymer is polymer-noble metal hybrid materials. Polymer-noble metal hybrid materials are generally chemically inert with a surrounding electrolyte, such as those with noble metals that are resistant to oxidation. An example of a polymer-noble metal hybrid material is a platinum-polymer hybrid material. Examples of conductive polishing materials, including conductive fibers, are more fully described in co-pending U.S. patent application Ser. No. 10/033,732, filed on Dec. 27, 2001, entitled, “Conductive Polishing Article For Electrochemical Mechanical Polishing”, which is incorporated herein by reference in its entirety. The invention also contemplates the use of organic or inorganic materials that may be used as fibers described herein.

The fiber material may be solid or hollow in nature. The fiber length is in the range between about 1 μm and about 1000 mm with a diameter between about 0.1 μm and about 1 mm. In one aspect, the diameter of fiber may be between about 5 μm to about 200 μm with an aspect ratio of length to diameter of about 5 or greater, such as about 10 or greater, for conductive polymer composites and foams, such as conductive fibers disposed in polyurethane. The cross-sectional area of the fiber may be circular, elliptical, star-patterned, “snow flaked”, or of any other shape of manufactured dielectric or conductive fibers. High aspect ratio fibers having a length between about 5 mm and about 1000 mm in length and between about 5 μm and about 1000 μm in diameter may be used for forming meshes, loops, fabrics or cloths, of the conductive fibers. The fibers may also have an elasticity modulus in the range between about 10 ⁴ psi and about 10 ⁸ psi. However, the invention contemplates any elastic modulus necessary to provide for compliant, elastic fibers in the polishing articles and processes described herein.

Conductive material disposed on the conductive or dielectric fiber material generally include conductive inorganic compounds, such as a metal, a metal alloy, a carbon-based material, a conductive ceramic material, a metal inorganic compound, or combinations thereof. Examples of metal that may be used for the conductive material coatings herein include noble metals, tin, lead, copper, nickel, cobalt, and combinations thereof. Noble metals include gold, platinum, palladium, iridium, rhenium, rhodium, rhenium, ruthenium, osmium, and combinations thereof, of which gold and platinum are preferred. The invention also contemplates the use of other metals for the conductive material coatings than those illustrated herein. Carbon-based material includes carbon black, graphite, and carbon particles capable of being affixed to the fiber surface. Examples of ceramic materials include niobium carbide (NbC), zirconium carbide (ZrC), tantalum carbide (TaC), titanium carbide (TiC), tungsten carbide (WC), and combinations thereof. The invention also contemplates the use of other metals, other carbon-based materials, and other ceramic materials for the conductive material coatings than those illustrated herein. Metal inorganic compounds include, for example, copper sulfide or danjenite, Cu ₉ S ₅ , disposed on polymeric fibers, such as acrylic or nylon fibers. The danjenite coated fibers are commercially available under the tradename Thunderon® from Nihon Sanmo Dyeing Co., Ltd, of Japan. The Thunderon® fibers typically have a coating of danjenite, Cu ₉ S ₅ , between about 0.03 μm and about 0.1 μm and have been observed to have conductivities of about 40 Ω/cm. The conductive coating may be disposed directly on the fiber by plating, coating, physical vapor deposition, chemical deposition, binding, or bonding of the conductive materials. Additionally, a nucleation, or seed, layer of a conductive material, for example, copper, cobalt or nickel, may be used to improve adhesion between the conductive material and the fiber material. The conductive material may be disposed on individual dielectric or conductive fibers of variable lengths as well as on shaped loops, foams, and cloths or fabrics made out of the dielectric or conductive fiber material.

An example of a suitable conductive fiber is a polyethylene fiber coated with gold. Additional examples of the conductive fibers include acrylic fibers plated with gold and nylon fibers coated with rhodium. An example of a conductive fiber using a nucleation material is a nylon fiber coated with a copper seed layer and a gold layer disposed on the copper layer.

The conductive fillers may include carbon based materials or conductive particles and fibers. Examples of conductive carbon-based materials include carbon powder, carbon fibers, carbon nanotubes, carbon nanofoam, carbon aerogels, graphite, and combinations thereof. Examples of conductive particles or fibers include intrinsically conductive polymers, dielectric or conductive particles coated with a conductive material, dielectric filler materials coated in conductive materials, conductive inorganic particles including metal particles such as gold, platinum, tin, lead and other metal or metal alloy particles, conductive ceramic particle, and combinations thereof. The conductive fillers may be partially or completely coated with a metal, such as a noble metal, a carbon-based material, conductive ceramic material, a metal inorganic compound, or combinations thereof, as described herein. An example of a filler material is a carbon fiber or graphite coated with copper or nickel. Conductive fillers may be spherical, elliptical, longitudinal with certain aspect ratio, such as 2 or greater, or of any other shape of manufactured fillers. Filler materials are broadly defined herein as materials that may be disposed in a second material to alter, the physical, chemical, or electrical properties of the second material. As such, filler materials may also include dielectric or conductive fiber material partially or completely coated in a conductive metal or conductive polymers as described herein. The fillers of dielectric or conductive fiber material partially or completely coated in a conductive metal or conductive polymers may also be complete fibers or pieces of fibers.

The conductive materials are used to coat both dielectric and conductive fibers and fillers to provide a desired level of conductivity for forming the conductive polishing material. Generally, the coating of conductive material is deposited on the fiber and/or filler material to a thickness between about 0.01 μm and about 50 μm, such as between about 0.02 μm and about 10 μm. The coating typically results in fibers or fillers having resistivities less than about 100 Ω-cm, such as between about 0.001 Ω-cm and about 32 Ω-cm. The invention contemplates that resistivities are dependent on the materials of both the fiber or filler and the coating used, and may exhibit resistivities of the conductive material coating, for example, platinum, which has a resistivity 9.81 Ω-cm at 0° C. An example of a suitable conductive fiber includes a nylon fiber coated with about 0.1 μm copper, nickel, or cobalt, and about 2 μm of gold disposed on the copper, nickel, or cobalt layer, with a total diameter of the fiber between about 30 μm and about 90 μm.

The conductive polishing material may include a combination of the conductive or dielectric fibers material at least partially coated or covered with an additional conductive material and conductive fillers for achieving a desired electrical conductivity or other polishing article properties. An example of a combination is the used of gold coated nylon fibers and graphite as the conductive material comprising at least a portion of a conductive polishing material.

The conductive fiber material, the conductive filler material, or combinations thereof, may be dispersed in a binder material or form a composite conductive polishing material. One form of binder material is a conventional polishing material. Conventional polishing materials are generally dielectric materials such as dielectric polymeric materials. Examples of dielectric polymeric polishing materials include polyurethane and polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), polytetrafluoroethylene polymers, polystyrene, ethylene-propylene-diene-methylene (EPDM), or combinations thereof, and other polishing materials used in polishing substrate surfaces. The conventional polishing material may also include felt fibers impregnated in urethane or be in a foamed state. The invention contemplates that any conventional polishing material may be used as a binder material (also known as a matrix) with the conductive fibers and fillers described herein.

Additives may be added to the binder material to assist the dispersion of conductive fibers, conductive fillers or combinations thereof, in the polymer materials. Additives may be used to improve the mechanical, thermal, and electrical properties of the polishing material formed from the fibers and/or fillers and the binder material. Additives include cross-linkers for improving polymer cross-linking and dispersants for dispersing conductive fibers or conductive fillers more uniformly in the binder material. Examples of cross-linkers include amino compounds, silane crosslinkers, polyisocyanate compounds, and combinations thereof. Examples of dispersants include N-substituted long-chain alkenyl succinimides, amine salts of high-molecular-weight organic acids, co-polymers of methacrylic or acrylic acid derivatives containing polar groups such as amines, amides, imines, imides, hydroxyl, ether, Ethylene-propylene copolymers containing polar groups such as amines, amides, imines, imides, hydroxyl, ether. In addition sulfur containing compounds, such as thioglycolic acid and related esters have been observed as effective dispersers for gold coated fibers and fillers in binder materials. The invention contemplates that the amount and types of additives will vary for the fiber or filler material as well as the binder material used, and the above examples are illustrative and should not be construed or interpreted as limiting the scope of the invention.

Further, a mesh of the conductive fiber and/or filler material may be formed in the binder material by providing sufficient amounts of conductive fiber and/or conductive filler material to form a physically continuous or electrically continuous medium or phase in the binder material. The conductive fibers and/or conductive fillers generally comprise between about 2 wt. % and about 85 wt. %, such as between about 5 wt. % and about 60 wt. %, of the polishing material when combined with a polymeric binder material.

An interwoven fabric or cloth of the fiber material coated with a conductive material, and optionally, a conductive filler, may be disposed in the binder. The fiber material coated with a conductive material may be interwoven to form a yarn. The yarns may be brought together to make a conductive mesh with the help of adhesives or coatings. The yarn may be disposed as a conductive element in a polishing pad material or may be woven into a cloth or fabric.

Alternatively, the conductive fibers and/or fillers may be combined with a bonding agent to form a composite conductive polishing material. Examples of suitable bonding agents include epoxies, silicones, urethanes, polyimides, a polyamide, a fluoropolymer, fluorinated derivatives thereof, or combinations thereof. Additional conductive material, such as conductive polymers, additional conductive fillers, or combinations thereof, may be used with the bonding agent for achieving desired electrical conductivity or other polishing article properties. The conductive fibers and/or fillers may include between about 2 wt. % and about 85 wt. %, such as between about 5 wt. % and about 60 wt. %, of the composite conductive polishing material.

The conductive fiber and/or filler material may be used to form conductive polishing materials or articles having bulk or surface resistivity of about 50 Ω-cm or less, such as a resistivity of about 3 Ω-cm or less. In one aspect of the polishing article, the polishing article or polishing surface of the polishing article has a resistivity of about 1 Ω-cm or less. Generally, the conductive polishing material or the composite of the conductive polishing material and conventional polishing material are provided to produce a conductive polishing article having a bulk resistivity or a bulk surface resistivity of about 50 Ω-cm or less. An example of a composite of the conductive polishing material and conventional polishing material includes gold or carbon coated fibers which exhibit resistivities of 1 Ω-cm or less, disposed in a conventional polishing material of polyurethane in sufficient amounts to provide a polishing article having a bulk resistivity of about 10 Ω-cm or less.

The conductive polishing materials formed from the conductive fibers and/or fillers described herein generally have mechanical properties that do not degrade under sustained electric fields and are resistant to degradation in acidic or basic electrolytes. The conductive material and any binder material used are combined to have equivalent mechanical properties, if applicable, of conventional polishing materials used in a conventional polishing article. For example, the conductive polishing material, either alone or in combination with a binder material, has a hardness of about 100 or less on the Shore D Hardness scale for polymeric materials as described by the American Society for Testing and Materials (ASTM), headquartered in Philadelphia, Pa. In one aspect, the conductive material has a hardness of about 80 or less on the Shore D Hardness scale for polymeric materials. The conductive polishing portion 310 generally includes a surface roughness of about 500 microns or less. The properties of the polishing pad are generally designed to reduce or minimize scratching of the substrate surfaces during mechanical polishing and when applying a bias to the substrate surface.

Polishing Article Structures

In one aspect, the polishing article is composed of a single layer of conductive polishing material described herein disposed on a support. In another aspect, the polishing article may comprise a plurality of material layers including at least one conductive material on the substrate surface or providing for a conductive surface for contacting a substrate and at least one article support portion or sub-pad.

FIG. 3 is a partial cross-sectional view of one embodiment of a polishing article 205 . Polishing article 205 illustrated in FIG. 3 comprises a composite polishing article having a conductive polishing portion 310 for polishing a substrate surface and an article support, or sub-pad, portion 320 .

The conductive polishing portion 310 may comprise a conductive polishing material including the conductive fibers and/or conductive fillers as described herein. For example, the conductive polishing portion 310 may include a conductive material comprising conductive fibers and/or conductive fillers dispersed in a polymeric material. The conductive fillers may be disposed in a polymer binder. The conductive fillers may include soft conductive materials disposed in a polymer binder. Soft conductive materials generally have a hardness and modulus less than or equal to about that of copper. Examples of soft conductive materials include gold, tin, palladium, palladium-tin alloys, platinum, and lead, among other conductive metals, alloys and ceramic composites softer than copper. The invention contemplates the use of other conductive fillers harder than copper if their size is small enough not to scratch polishing substrate. Further, the conductive polishing portion may include one or more loops, coils, or rings of conductive fibers, or conductive fibers interwoven to form a conductive fabric or cloth. The conductive polishing portion 310 may also be comprised of multiple layers of conductive materials, for example, multiple layers of conductive cloth or fabric.

One example of the conductive polishing portion 310 includes gold coated nylon fibers and graphite particles disposed in polyurethane. Another example includes graphite particles and/or carbon fibers disposed in polyurethane or silicone. Another example includes gold or tin particles dispersed in polyurethane matrix.

In another embodiment, the conductive polishing portion 310 may have abrasive particles 360 disposed therein. At least some of the abrasive particles 360 are exposed on an upper polishing surface 370 of the conductive polishing portion 310 . The abrasive particles 360 generally are configured to remove the passivation layer of the metal surface of the substrate being polished, thereby exposing the underlying metal to the electrolyte and electrochemical activity, thereby enhancing the rate of polishing during processing. Examples of abrasive particles 360 include ceramic, inorganic, organic, or polymer particle strong enough to break the passivation layer formed at the metal surface. Polymer particles may be solid or spongy to tailor the wear rate of the polishing portion 310 .

The article support portion 320 generally has the same or smaller diameter or width of the conductive polishing portion 310 . However, the invention contemplates the article support portion 320 having a greater width or diameter than the conductive polishing portion 310 . While the figures herein illustrate a circular conductive polishing portion 310 and article support portion 320 , the invention contemplates that the conductive polishing portion 310 , the article support portion 320 , or both may have different shapes such as rectangular surfaces or elliptical surfaces. The invention further contemplates that the conductive polishing portion 310 , the article support portion 320 , or both, may form a linear web or belt of material.

The article support portion 320 may comprise inert materials in the polishing process and are resistant to being consumed or damaged during ECMP. For example, the article support portion may be comprised of conventional polishing materials, including polymeric materials, for example, polyurethane and polyurethane mixed with fillers, polycarbonate, polyphenylene sulfide (PPS), ethylene-propylene-diene-methylene (EPDM), polytetrafluoroethylene polymers, or combinations thereof, and other polishing materials used in polishing substrate surfaces. The article support portion 320 may be a conventional soft material, such as compressed felt fibers impregnated with urethane, for absorbing some of the pressure applied between the polishing article 205 and the carrier head 130 during processing. The soft material may have a Shore A hardness between about 20 and about 90.

Alternatively, the article support portion 320 may be made from a conductive material compatible with surrounding electrolyte that would not detrimentally affect polishing including conductive noble metals or a conductive polymer, to provide electrical conduction across the polishing article. Examples of noble metals include gold, platinum, palladium, iridium, rhenium, rhodium, rhenium, ruthenium, osmium, and combinations thereof, of which gold and platinum are preferred. Materials that are reactive with the surrounding electrolyte, such as copper, may be used if such materials are isolated from the surrounding electrolyte by an inert material, such as a conventional polishing material or a noble metal.

When the article support portion 320 is conductive, the article support portion 320 may have a greater conductivity, i.e., lower resistivity, than the conductive polishing portion 310 . For example, the conductive polishing portion 310 may have a resistivity of about 1.0 Ω-cm or less as compared to an article support portion 320 comprising platinum, which has a resistivity 9.81 μΩ-cm at 0° C. A conductive article support portion 320 may provide for uniform bias or current to minimize conductive resistance along the surface of the article, for example, the radius of the article, during polishing for uniform anodic dissolution across the substrate surface. A conductive article support portion 320 may be coupled to a power source for transferring power to the conductive polishing portion 310 .

Generally, the conductive polishing portion 310 is adhered to the article support portion 320 by a conventional adhesive suitable for use with polishing materials and in polishing processes. The invention contemplates the use of other means to attach the conductive polishing portion 310 onto the article support portion 320 such as compression molding and lamination. The adhesive may be conductive or dielectric depending on the requirements of the process or the desires of the manufacturer. The article support portion 320 may be affixed to a support, such as disc 206 , by an adhesive or mechanical clamp. Alternatively, if polishing article 205 only includes a conductive polishing portion 310 , the conductive polishing portion may be affixed to a support, such as disc 206 , by an adhesive or mechanical clamp.

The conductive polishing portion 310 and the article support portion 320 of the polishing article 205 are generally permeable to the electrolyte. A plurality of perforations may be formed, respectively, in the conductive polishing portion 310 and the article support portion 320 to facilitate fluid flow therethrough. The plurality of perforations allows electrolyte to flow through and contact the surface during processing. The perforations may be inherently formed during manufacturing, such as between weaves in a conductive fabric or cloth, or may be formed and patterned through the materials by mechanical means. The perforations may be formed partially or completely through each layer of the polishing article 205 . The perforations of the conductive polishing portion 310 and the perforations of the article support portion 320 may be aligned to facilitate fluid flow therethrough.

Examples of perforations 350 formed in the polishing article 205 may include apertures in the polishing article having a diameter between about 0.02 inches (0.5 millimeters) and about 0.4 inches (10 mm). The thickness of the polishing article 205 may be between about 0.1 mm and about 5 mm. For example, perforations may be spaced between about 0.1 inches and about 1 inch from one another.

The polishing article 205 may have a perforation density between about 20% and about 80% of the polishing article in order to provide sufficient mass flow of electrolyte across the polishing article surface. However, the invention contemplates perforation densities below or above the perforation density described herein that may be used to control fluid flow therethrough. In one example, a perforation density of about 50% has been observed to provide sufficient electrolyte flow to facilitate uniform anodic dissolution from the substrate surface. Perforation density is broadly described herein as the volume of polishing article that the perforations comprise. The perforation density includes the aggregate number and diameter or size of the perforations, of the surface or body of the polishing article when perforations are formed in the polishing article 205 .

The perforation size and density is selected to provide uniform distribution of electrolyte through the polishing article 205 to a substrate surface. Generally, the perforation size, perforation density, and organization of the perforations of both the conductive polishing portion 310 and the article support portion 320 are configured and aligned to each other to provide for sufficient mass flow of electrolyte through the conductive polishing portion 310 and the article support portion 320 to the substrate surface.

Grooves may be disposed in the polishing article 205 to promote electrolyte flow across the polishing article 205 to provide effective or uniform electrolyte flow with the substrate surface for anodic dissolution or electroplating processes. The grooves may be partially formed in a single layer or through multiple layers. The invention contemplates grooves being formed in the upper layer or polishing surface that contacts the substrate surface. To provide increased or controlled electrolyte flow to the surface of the polishing article, a portion or plurality of the perforations may interconnect with the grooves. Alternatively, the all or none of the perforations may interconnect with the grooves disposed in the polishing article 205 .

Examples of grooves used to facilitate electrolyte flow include linear grooves, arcuate grooves, annular concentric grooves, radial grooves, and helical grooves among others. The grooves formed in the article 205 may have a cross-section that is square, circular, semi-circular, or any other shape that may facilitate fluid flow across the surface of the polishing article. The grooves may intersect each other. The grooves may be configured into patterns, such as an intersecting X-Y pattern disposed on the polishing surface or an intersecting triangular pattern formed on the polishing surface, or combinations thereof, to improve electrolyte flow over the surface of the substrate.

The grooves may be spaced between about 30 mils and about 300 mils apart from one another. Generally, grooves formed in the polishing article have a width between about 5 mils and about 30 mils, but may vary in size as required for polishing. An example of a groove pattern includes grooves of about 10 mils wide spaced about 60 mils apart from one another. Any suitable groove configuration, size, diameter, cross-sectional shape, or spacing may be used to provide the desired flow of electrolyte. Additional cross sections and groove configurations are more fully described in co-pending U.S. Patent Provisional Application Ser. No. 60/328,434, filed on Oct. 11, 2001, entitled “Method And Apparatus For Polishing Substrates,” which is incorporated herein by reference in its entirety.

Electrolyte transport to the surface of the substrate may be enhanced by intersecting some of the perforations with the grooves to allow electrolyte to enter through one set of perforation, be evenly distributed around the substrate surface by the grooves, used in processing a substrate, and then processing electrolyte is refreshed by additional electrolyte flowing through the perforations. An example of a pad perforation and grooving is more fully described in U.S. patent application Ser. No. 10/026,854, filed Dec. 20, 2001, which is incorporated by reference in its entirety.

Examples of polishing articles having perforations and grooves are as follows. FIG. 4 is a top plan view of one embodiment of a grooved polishing article. A round pad 440 of the polishing article 205 is shown having a plurality of perforations 446 of a sufficient size and organization to allow the flow of electrolyte to the substrate surface. The perforations 446 can be spaced between about 0.1 inches and about 1 inch from one another. The perforations may be circular perforations having a diameter of between about 0.02 inches (0.5 millimeters) and about 0.4 inches (10 mm). Further the number and shape of the perforations may vary depending upon the apparatus, processing parameters, and ECMP compositions being used.

Grooves 442 are formed in the polishing surface 448 of the polishing article 205 therein to assist transport of fresh electrolyte from the bulk solution from basin 202 to the gap between the substrate and the polishing article. The grooves 442 may have various patterns, including a groove pattern of substantially circular concentric grooves on the polishing surface 448 as shown in FIG. 4, an X-Y pattern as shown in FIG. 5 and a triangular pattern as shown in FIG. 6.

FIG. 5 is a top plan view of another embodiment of a polishing pad having grooves 542 disposed in an X-Y pattern on the polishing portion 548 of a polishing pad 540 . Perforations 546 may be disposed at the intersections of the vertically and horizontally disposed grooves, and may also be disposed on a vertical groove, a horizontal groove, or disposed in the polishing article 548 outside of the grooves 542 . The perforations 546 and grooves 542 are disposed in the inner diameter 544 of the polishing article and the outer diameter 550 of the polishing pad 540 may be free of perforations and grooves and perforations.

FIG. 6 is another embodiment of patterned polishing article 640 . In this embodiment, grooves may be disposed in an X-Y pattern with diagonally disposed grooves 645 intersecting the X-Y patterned grooves 642 . The diagonal grooves 645 may be disposed at an angle from any of the X-Y grooves 642 , for example, between about 30° and about 60° from any of the X-Y grooves 642 . Perforations 646 may be disposed at the intersections of the X-Y grooves 642 , the intersections of the X-Y grooves 642 and diagonal grooves 645 , along any of the grooves 642 and 645 , or disposed in the polishing article 648 outside of the grooves 642 and 645 . The perforations 646 and grooves 642 are disposed in the inner diameter 644 of the polishing article and the outer diameter 650 of the polishing pad 640 may be free of perforations and grooves.

Additional examples of groove patterns, such as spiraling grooves, serpentine grooves, and turbine grooves, are more fully described in co-pending U.S. Patent Provisional Application Ser. No. 60/328,434, filed on Oct. 11, 2001, entitled “Method And Apparatus For Polishing Substrates”, which is incorporated herein by reference in its entirety.

In addition to the perforations and grooves in the polishing article 205 , the conductive polishing portion 310 may be embossed to include surface texture. The embossment may improve the transportation of electrolytes, removed substrate materials, by products, and particles. The embossment may also reduce scratches to polishing substrate and modify the friction between polishing substrate and the polishing article 205 . The embossed surface textures distribute uniformly across the conductive polishing portion 310 . Embossed surface textures may include structures such as pyramids, islands, crosses along with circular, rectangular and square shapes, among other geometric forms. The invention contemplates other texture structures embossed on conductive polishing portion 310 . The embossed surface may cover 5 to 95 percent surface area of the conductive polishing portion 310 , such as between 15 percent and 90 percent surface area of the conductive polishing portion 310 .

Conductive Polishing Surfaces

FIG. 7A is a top sectional view of one embodiment of a conductive cloth or fabric 700 that may be used to form a conductive polishing portion 310 of the polishing article 205 . The conductive cloth of fabric is composed of interwoven fibers 710 coated with a conductive material as described herein.

In one embodiment, a weave or basket-weave pattern of the interwoven fibers 710 in the vertical 720 and horizontal 730 (shown in the plane of FIG. 7A) directions is illustrated in FIG. 7A. The invention contemplates other form of fabrics, such as yarns, or different interwoven, web, or mesh patterns to form the conductive cloth or fabric 700 . In one aspect, the fibers 710 are interwoven to provide passages 740 in the fabric 700 . The passages 740 allow electrolyte or fluid flow, including ions and electrolyte components, through the fabric 700 . The conductive fabric 700 may be disposed in a polymeric binder, such as polyurethane. Conductive fillers may also be disposed in such a polymeric binder.

FIG. 7B is a partial cross-sectional view of the conductive cloth or fabric 700 disposed on the article support portion 320 of the article 205 . The conductive cloth or fabric 700 may be disposed as one or more continuous layers over the article support portion 320 including any perforations 350 formed in the article support portion 320 . The cloth or fabric 700 may be secured to the article support portion 320 by an adhesive. The fabric 700 is adapted to allow electrolyte flow through the fibers, weaves, or passages formed in the cloth or fabric 700 when immersed in an electrolyte solution. Optionally an interposed layer may be included between the cloth or fabric 700 and article support portion 320 . The interposed layer is permeable or includes perforations aligned with the perforations 350 for the electrolyte flow through the article 205 .

Alternatively, the fabric 700 may also be perforated to increase electrolyte flow therethrough if the passages 740 are determined to not be sufficient to allow effective flow of electrolyte through the fabric 700 , i.e., metal ions cannot diffuse through. The fabric 700 is typically adapted or perorated to allow flow rates of electrolyte solutions of up to about 20 gallons per minute.

FIG. 7C is a partial cross-sectional view of the cloth or fabric 700 may be patterned with perforations 750 to match the pattern of perforations 350 in the article support portion 320 . Alternatively, some or all of the perforations 750 of the conductive cloth or fabric 700 may not be aligned with the perforations 350 of the article support portion 320 . Aligning or non-aligning of perforations allow the operator or manufacturer to control the volume or flow rate of electrolyte through the polishing article to contact the substrate surface.

An example of the fabric 700 is an interwoven basket weave of between about 8 and about 10 fibers wide with the fiber comprising a nylon fiber coated with gold. An example of the fiber is a nylon fiber, about 0.1 μm of cobalt, copper, or nickel material disposed on the nylon fiber, and about 2 μm of gold disposed on the cobalt, copper, or nickel material.

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