DEFINITIONS

[0087] Unless otherwise specified, all percentages expressed herein should be understood to refer to percentages by weight. Also, the term “about,” when used in reference to a range of values, should be understood to refer to either value in the range, or to both values in the range.

[0088] As used herein, the phrases “contains substantially no” and “is substantially free from,” in reference to a composition should be understood to mean:

[0089] for components such as abrasives, alkanolamines including AEEA, polar organic solvents including non-hydroxyl-containing amines, water, organic solvents, hydroxylamine and hydroxylamine derivatives, the aforementioned phrases should be understood to mean that the composition contains less than 1.5%, preferably less than about 1%, more preferably less than about 0.1%, of the specific element mentioned thereafter;

[0090] for minor components including chelating agents, corrosion inhibitors, surfactants, and the like, the aforementioned phrases should be understood to mean that the composition contains less than 0.2%, preferably less than about 0.1%, most preferably less than about 0.01%, of the specific element mention thereafter; and

[0091] for trace contaminants such as metal ions, substantially free is defined in the specification, e.g., less than 10 ppm metals and metal ions.

[0092] Preferably, when one of the aforementioned phrases is used, the composition is completely free of any added element specifically mentioned thereafter, or at least does not contain the added element in an amount such that the element affects the efficacy, storability, usability regarding necessary safety concerns, or stability of the composition.

[0093] Unless otherwise specified, and wherever possible, a compound should generally not be characterized under more than one enumerated element of the composition according to the invention. If a compound is capable of being characterized under, for example, two enumerated embodiments of the composition, such a compound may be characterized herein only under either one of the two enumerated elements, but not under both. At times, the distinction may be made based on the content of the compound in the composition. For instance, catechol or gallic acid can act primarily as a corrosion inhibitor at “high” concentrations, i.e. about 0.5% to 20%, or primarily as a metal chelator at “low” concentrations, i.e., in the ppm to 0.5 wt % range.

[0094] As used herein, hydroxylamine and hydroxyamine derivatives are not considered organic, despite the organic substituents that may be present on substituted hydroxylamine.

DETAILED DESCRIPTION OF THE INVENTION

[0095] Now CMP appears to be entering a new growth phase, which emphasizes a new group of priorities. These priorities include reducing CMP defects in metal and insulator layers, better planarity within wafer and wafer to wafer, a premixed concentrate that avoids point of use mixing; a generic post CMP cleaning an a high polishing selectivity. There are also environmental, health and safety issues. These issues are: (1) better vapor handling (or educed requirement for vapor handling), (2) possible slurry recycling (or spent slurry residues that are more environmentally friendly), (3) more stable chemistries to be used with the abrasives and (4) better end point detection (EPD) during the polishing steps.

[0096] This invention does not deal with the composition or type of abrasive (slurry particle size, shape, size distribution % solids) in the slurry. But the slurries have numerous other components (oxidizing agents, stabilizers, etc.) that can be improved through additional experiments. These components include solutions pH, type of chemistry and chemical and slurry purity. This proposed invention focuses on the chemistry and its possible pH, Zeta potential, contact angle (“wetting”) and other associated effects.

[0097] The first phase of the invention focuses on understanding the CMP chemistry based on hydroxylamine (HDA) and hydroxylamine derivatives (the chloride, sulfate, nitrate or other salts) under different pH conditions HDA (NH ₂ OH) can be viewed a hybrid between hydrazine (H ₂ N—NH ₂ ) and hydrogen peroxide (H ₂ O ₂ ) in its redox chemistry. HDA is a more selective (controllable) oxidation and reducing agent. This dual capability is achieved by shifting the pH from the acid to basic media, as shown below. 2

[0098] The redox potential for hydrogen peroxide (acidic) and HDA (in acid and base) (E _v at SHE) are given: 3

[0099] Fortunately few metal ions are reduced to the zero oxidation state, and this is important in CMP processes to avoid contamination of the wafer surface with metal particles. Hydrogen peroxide polishing systems are also not very stable, being easily decomposed by trace amounts of transition metals. Currently, the CMP consumable suppliers need to have a two component delivery system—one for the slurry and the second for the peroxide.

[0100] Besides being a redox agent, HDA, like ammonia, can form complex salts with many metals including Al(SO ₄ ) ₂ *NH ₂ OH*H ₂ O and Cu(x) ₂ *NH ₂ OH*H ₂ O.

[0101] Another important advantage of using hydroxylamine type compounds is their decomposition products. Depending on the solution pH and metal ions and concentration, HDA will decompose to water, nitrogen, ammonia and N ₂ 0. The formation of nitrogen even takes place through a slow internal redox reaction at pHs above 8.

[0102] Metal Polishing

[0103] The metals currently being studied for the CMP process include AI, Cu, and W. Pourbaix diagrams can be used to examine the best regions (E _v versus pH) for the various polishing rates (corrosion). No two metal or alloy systems will have the same regions of chemical activity. Using this data may also allow CMP polishing conditions to be chosen so that the selectivity of the polishing rate of one metal is significantly greater than another metal (or oxide or nitride material) on the same wafer. Pourbaix diagrams can be obtained for all metals, oxides, nitrides and other materials appearing on wafer surfaces wherever they are available. By overlaying the diagrams, pH regions can be roughly determined which may be corrosive for one material while passivating for another. This could be one tool that is useful in seeking high selectivities. FIG. 1 shows the Pourbaix diagram for Cu. This diagram, based on thermodynamic data, shows that copper, copper (I) oxide and copper (II) oxide can exist together in the redox environment of our world (delineated by the sloping parallel dashed lines). The data also shows that none of these three compounds can exist at pHs less than 6.8, and at oxidation potentials above ˜0.2 volts, all of these compounds will dissolve.

[0104] At higher pH values the three compounds can exist in aqueous solution, including with various anions (Cu(OH) ₂ and CuO ²⁻ ).

[0105] This invention proposes that usage of HDA or its salts can be used to remove copper using CMP methods. The advantage of using the HDA based chemistries is that its oxidation potential (E _v =−1.05 volts) will allow the Cu to be removed at higher pHs than conventional chemistries that require a more acidic environment (lower pH).

[0106] Recent experiments with 10% hydroxylamine nitrate in DI water showed that 3000 A copper metal on a 300 A Ti metal layer could be cleanly removed; @ pH 3 ˜100 Å/min, pH 4˜125 Å/min and pH 5˜1000 Å/min. This is exactly the reverse of the expected pH effect from the Pourbaix diagram and is the result of the oxidation potential.

[0107] When the free base hydroxylamine (5% in DI water) was tested with the same type of copper wafer, the etching rate dropped to 75 Å/min compared to a 10% ammonium hydroxide with a 100 Å/min rate. It is known that ammonium hydroxide solutions will dissolve copper very slowly, but if oxidizing agents (air or oxygen) are introduced then the etching rate can be quite measurable. The hydroxylamine solution is a reducing medium and so the copper etch is slower. The data does show that HDA could be used for very controlled (slow) etch rates.

[0108] FIG. 2 shows the Pourbaix diagram for aluminum metal. The data shows that the pure metal Al cannot exist in the normal redox regime but only as an oxide coating. Between a pH of 4 and 10 this oxide layer will not dissolve.

[0109] Experiments with blanket Al metal wafers should again show the Al metal and its oxide layer can be removed by using either HAN at a pH of 4 or at 10 since it is necessary to remove the oxide layer before the metal layer can be polished. Concentration ranges will vary from 0.5 to 10 wt %.

[0110] Our understanding of HDA and its purification has given us a unique understanding of HDA's capacities to aid in removing mobile ions (sodium, potassium, iron and other transition metal ions) from the wafer's surface. It is critical that all phases of the CMP process minimize the mobile and transition metal ion concentrations on the wafer surfaces.

[0111] It is possible to add chelating agents; e.g., alkyl beta-diketones (2,4 pentanedione, etc.) or EDTA or aromatic phenolic aldehydes (salicylaldehyde, etc.) or other agents. These components can be added in concentrations ranging from 2 ppm to 15 wt %. Higher concentrations could be used but there is a possibility that these chelators could “plate” on the chip's structures, or would alter the effectiveness of the over all chemistry. The ketone-based systems may react with the hydroxylamine based products to form oxime derivatives which are good chelating agents in their own right.

[0112] Other agents could include bis(hydroxypropyl)hydroxylamine, anisaldehyde or even alpha hydroxy isobutyric acid as a chelator. Other compounds could also be aromatic dioxygenated compounds, benzoin and benzil.

[0113] A recently reported water soluble iron chelator is O-TRENSOX which can be used in the HDA-based chemistries and should show promising results.

[0114] Though catechol and catechol derivatives are known to be good chelating agents at high pH conditions (because of the mono or dianion) only a little work has been done with this class of compounds under acidic conditions. There are reports that catechol will complex with aluminum at pH 3-5.

[0115] Gallic acid is also another compound that under mildly acidic conditions could have complexing powers with certain Group 3 through 12 metals (IUPAC nomenclature). The catechol and gallic acid family of compounds can act as either corrosion inhibitors (at “high” concentrations; i.e. 0.5 to 15-20 wt %) compounds, or as metal chelators in the ppm to 0.5 wt % range.

[0116] For many oxygenated compounds (phenols, alcohols, some organic acids, etc.) it is important that the oxygen atoms fill in vacancies on the metal surfaces. These vacancies are formed because of poorly organized surface oxide films and/or the pH retards the reactions or other anions interfere with the film uniformity. If the chemical environment is too aggressive then the corrosion inhibitor that is absorbed on the surface will be dissociated from the surface, but will carry a metal ion with it. Now the corrosion inhibitor can give the appearance of an attacking species.

[0117] Other benefits to using HDA-based chemistries are the environment, safety and health aspects. HDA under basic conditions decomposes to water, nitrogen, and small concentrations of NH ₃ . HDA is mildly caustic compared to other nitrogen containing compounds, i.e., organic amines. Under acidic conditions, hydroxylamine compounds are very stable in aqueous solutions.

[0118] CMP users do not like working with sodium or potassium hydroxide because of the potential mobile ion contamination. Many users have changed over to ammonium hydroxide which does not have the same magnitude of a mobile ion problem and does have a lower surface tension (better surface contact). The main problem with ammonium hydroxide is its odor which requires very effective ventilation systems.

[0119] Another important area is to understand and, if possible, to adjust the slurries' Zeta potential. The Zeta potential is a electrostatic potential measurement of the interaction of the electrostatic double layer ions (anions and cations) that exists around each particle in a solution. The Zeta potential depending on the type of particle; i.e. aluminum, silica, manganese dioxide etc., and the solution pH, can be positive or negative. Poorly designed slurries may have a Zeta potential which leads to settling of the slurry particles. This can be very detrimental to its performance during the CMP polishing process.

[0120] Another measure of Zeta potential is the isoelectric point (IEP) for a particle. The IEP is the pH at which the Zeta potential value is zero. The chemical composition and source will have significant effect on the IEP. Some selected values: aluminum oxide particles can vary between 3.8 to 9.4, while silicon oxide has a narrower range 1.5 to 3.7.

[0121] Some metal residue IEP values are 9.5 for TiO ₂ , while tungsten is somewhere around ˜1. Such wide ranges of values pose a major challenge to developing chemistries to control the Zeta potential of the particles that may eventually adhere to the wafer surface.

[0122] Another concern is that the Zeta potential between the slurry and metal particles and the wafer will be such that the particles will be attracted and adhere to the wafer surface. This will require that a post CMIP clean step remove the adhering particles.

[0123] The hydroxylamine or hydroxylamine salts can react with the particle surface through either a redox reaction or a normal chemical reaction with the terminal groups on the surface. Since the HDA chemistries can be chemically “tuned” by adjusting the pH and still be active for metal CMP (see Cu idea above), this will give us a wider process window to affect the solution slurry Zeta potential. Concentrations for this effect should be between 1 to 10 wt % because of HDA's single charge.

[0124] Another way to change the Zeta potential is to use surfactants (nonionic, cationic or anion) to reduce the surface charge on the wafer. The hydroxylamine chemistries can be matched with the appropriate surfactant. Experiments with octylphenol polyethylene (9-10 ethylene oxide units) at pH 9.5 did reduce the surface tension and also reduced surface roughness. Anionic surfactants can be used for particles that have positive Zeta potentials.

[0125] Oxide Polishing

[0126] Some of the films currently being planarized include TEOS, BPSG, PSG and SOG. Though this area of CMP has matured, EKC's HDA (50% hydroxylamine) chemistry with its “buffered” pH of 9.5 to 10.5, and low mobile ion concentration (Na and K) could be an important new chemistry for the current silicon oxide slurries.

[0127] The HDA free base material should be tested at various pH's (7-11) with a silica slurry. The amount of HDA used in the slurry should be 2 to 10%. SIMS data should show that the mobile ion content remained constant or was decreased.

[0128] Though ammonium hydroxide solutions will also polish the silicon surface, the vapors from the polishing process need to be handled (removed) in an effective manner. The HDA chemistries do not have the same smell intensity.

[0129] Work with ammonium salts added to fumed silica, in the pH range of 6-9 for oxide CMP slurry, shows surprising results. Though one expects the higher pH (9) to polish silicon oxide faster (traditional chemical attack of a base on the Si bond), Hayashi et al. had remarkable success at removing oxide at a pH 6 with a 0.1 molar ammonium salt solution (chloride, sulfate, etc). Even at pH 7 the rate was faster that at pH 9. The results suggest particle agglomeration (change in the electrical double layer by modifying the Zeta potential of the fumed silica), forming a “slush” on the particles and the oxide surface. It was also noticed that the residual particle count was reduced from 5×10 ⁵ to 2×10 ³ for a 6″ wafer. There is no reason that hydroxylamine salts at this or smaller concentration ranges should not have a similar effect on the polishing rate. The pK's between the two groups of salts are different which would allow us again to “fine tune” the polishing rates.

[0130] One theory is that colloidal silica is very sensitive to pH and undergoes flocculation at pH values near 8, due to the presence of insufficient alkali ions.

[0131] Ammonium bifluoride is another important ingredient to be evaluated in the above matrix. Silica dioxide has several solubility regions depending on pH. Ammonium bifluoride at low concentrations (>1×10 ⁻³ molar) and low pH (4-6) can be effective for expanding the “window” for dissolving silica structures. This chemistry region might open up an entirely new CMP processing window for ILD. The concentration ranges must be rather narrow, i.e., 1×10 ⁻⁵ to 1×10 ⁻² molar. At higher concentrations the chemistries start to act as conventional HF etching media (in the pH range 4-7) with very rapid etching.

[0132] One important area is the polishing of an oxide/nitride system and being able to achieve a high oxide to nitride selectivity. Nitride appears to undergoing slow oxidation to a silicon oxide type compound which undergoes the standard oxide polishing process. This reduces the desired polishing selectivity.

[0133] Since the HDA free base is a saturated nitrogen solution, and the free base reacts with oxygen thus creating a solution with very poor oxidizing potentials, it is possible that the nitride structures will not be readily attacked. Thus the oxide to nitride polishing selectivity should be enhanced.

[0134] Research would also be directed at determining if the HDA solutions are stable under the required CMP conditions and whether there is an enhanced selectivity among various other silicon oxide systems (SOG, TEOS, BPSG, etc.).

[0135] Post-CMP Clean

[0136] The chemical nature of the wafer surface (hydrophilic or hydrophobic) will effect the method and type of solution necessary to remove particles from the wafer surface after the polishing step. The particle charge relative to the wafer surface will determine the type of chemistry that will effectively remove the particles. Zeta potentials of the particles and the effect of the solution pH on this value will need to be understood. Alumina particles can be dislodged under acid conditions but silicon oxide material requires a basic solution.

[0137] At the same time it should be advantageous to use solution additives to remove metal contaminates from the wafer surface. Study of residual particle count and metal contamination levels on wafers from a post-clean procedure allows correlation of this information with the HDA solution pH and level of additives. These additives will include water soluble crown ethers and specific metal chelating agents or buffered citric acid solutions.

[0138] Though HDA and HDA related compounds can effect the particle and wafer surfaces through pH and redox chemistries, these chemical species only have a single ionic charge per molecule (though a reasonable charge density for the size of molecule involved). It may be necessary to augment the electrostatic double layer around the particles or on the wafer by adding “polyelectrolytes” which are highly charged compounds. Normally the polyelectrolytes are used in high enough concentration to “force” particles to clump together. In this invention we only want to add enough polyelectrolytes encourage the particles to repel each other and away from the wafer surfaces. This will enhance the post CMP cleaning step. The concentration for this affect could range from 1 part per thousand to 10 wt %.

[0139] There are several other types of redox reagents that also can be used in CMP applications which could be used by themselves or in conjunction with other chemistries, including hydroxylamine and its salts.

[0140] In accordance with another aspect of the invention, ammonium persulfate (ammonium peroxydisulfate) can be used to remove Al, copper or tungsten using CMP methods. Though ammonium persulfate has been used to strip copper metal films from electronic component boards, this material has not been used to remove Cu in a very controlled manner. We are not aware of this chemistry being used to polish Al metal under CMP process conditions.

[0141] The tungsten CMP process appears to operate through the tungstate (WO ₄ ⁼ ) ion. Though the current CMP processes are based on ferric nitrate or hydrogen peroxide under acid conditions another feasible route to obtain this species is to oxidize the W metal with an oxidizing agent under basic conditions. The tungstate should have maximum solubility at pH>6.

[0142] Normally ammonium persulfate solutions have a pH in the range of 2 to 3. This invention illustrates that by adjusting the oxidizing solution's pH to higher values, the resulting solution will be a very effective for polishing W metal films.

[0143] Additional Compositions and Processes

[0144] In addition to the aforementioned compositions and processes discussed above, the following describes preferred compositions and processes according to the invention. In one preferred embodiment, for example, a polishing composition is optionally but preferably substantially abrasive-free and can contain: optionally hydroxylamine; optionally at least one additive for controlling pH, e.g., an acid; at least one corrosion inhibitor, preferably a copper corrosion inhibitor, such as a copper (I) corrosion inhibitor and/or a copper (II) corrosion inhibitor, more preferably including benzotriazole or a salt or derivative thereof; water; and at least one hydroxylamine derivative having the following formula: 4

[0145] wherein R ₃ is hydrogen or a linear, branched, or cyclic hydrocarbon containing from 1 to 7 carbon atoms; and wherein X and Y are, independently, hydrogen or a linear, branched, or cyclic hydrocarbon containing from 1 to 7 carbon atoms, or wherein X and Y are linked together form a nitrogen-containing heterocyclic C ₄ -C ₇ ring. When X, Y, and R ₃ are all hydrogen, the compound is hydroxylamine.

[0146] Examples of derivatives of hydroxylamine according to the invention include, but are in no way limited to, hydroxylamine, N-methyl-hydroxylamine, N,N-dimethyl-hydroxylamine, N-ethyl-hydroxylamine, N,N-diethyl-hydroxylamine, methoxylamine, ethoxylamine, N-methyl-methoxylamine, and the like. As used herein, hydroxylamine is not an organic, and the boiling point and flash point of hydroxylamine and hydroxylamine derivatives is of no consequence to the formulation. It should be understood that hydroxylamine and its derivatives, as defined above, are available (and may be included in a composition according to the invention) as salts, e.g., sulfate salts, nitrate salts, phosphate salts, or the like, or a combination thereof, and the invention includes these forms of hydroxylamine compounds and their derivatives. These salts greatly increase the theoretical flash point of hydroxylamine derivatives. Therefore, in another embodiment, the composition contains hydroxylamine, a sulfate, nitrate, or phosphate salt of hydroxylamine, or a combination thereof. Hydroxylamines may not be desired in a subset of the formulations described herein. Therefore, in some embodiments, the composition according to the invention is substantially free from hydroxylamine.

[0147] In one embodiment, the composition according to the invention contains water. Water is preferred in a majority of residue removing compositions. Additionally, hydroxylamine is commercially available in an aqueous, i.e., a 50% aqueous, solution. Hydroxylamine derivatives are typically available in more concentrated aqueous forms, for example, 82% solutions with 18% water (as is the case with HAN, or hydroxylamine nitrate). However, hydroxylamine and/or hydroxylamine derivatives can be obtained or manufactured, in some instances and in some concentrations, in a water-free formulation.

[0148] In one embodiment, the composition can contain an acid, e.g., to adjust the pH. The acid may be inorganic (e.g., hydrochloric, hydrobromic, sulfuric, sulfurous, nitric, nitrous, phosphoric, phosphorous, or the like, or a combination thereof), organic (e.g., lactic, acetic, formic, propionic, butyric, benzoic, ascorbic, carbonic, gluconic, maleic, malonic, oxalic, succinic, tartaric, citric, gallic, a polycarboxylic acid such as EDTA, or the like, or a combination thereof), or a combination thereof. In addition, acids according to the invention may include salts of acids that still have acid functional moieties, e.g., a hydrogen ascorbate, a hydrogen carbonate, a hydrogen gluconate, a hydrogen maleate, a hydrogen malonate, a hydrogen oxalate, a hydrogen succinate, a hydrogen tartarate, a hydrogen citrate, a dihydrogen citrate, a hydrogen gallate, a dihydrogen gallate, a mono-, di-, or tri-substituted salt of EDTA, or the like, or a combination thereof. In an alternate embodiment, e.g., where higher pH rather than lower is desired, the composition can contain a base to adjust the pH. The base may be inorganic (e.g., a completely substituted salt of an inorganic acid, such as those mentioned above; hydrazine or a derivative thereof; a hydroxide salt, such as ammonium hydroxide, sodium hydroxide, lithium hydroxide, potassium hydroxide, calcium hydroxide, or the like, or a combination thereof; or the like; or a combination thereof), organic (e.g., a completely substituted salt of an organic acid, such as those mentioned above; a non-hydroxyl-containing amine, such as a substituted or unsubstituted aminobenzene, a substituted or unsubstituted pyridine, a substituted or unsubstituted pyrrole, a substituted or unsubstituted pyrrolidine, a substituted or unsubstituted pyrrolid(in)one, a substituted or unsubstituted carbazole, a substituted or unsubstituted indole, or the like, or a salt thereof, or a (co)polymer containing same, or a combination thereof; or the like; or a combination thereof), or a combination thereof. In an alternate embodiment, the composition may be substantially free from acids and/or bases to adjust pH.

[0149] Hydrazines and hydrazine derivatives suitable for use according to the invention can be represented by the following formula: 5

[0150] wherein R ₁ , R ₂ , R ₃ , and R ₄ are independently hydrogen; a hydroxyl group; optionally a substituted C ₁ -C ₆ straight, branched or cyclic hydrocarbon group; optionally a substituted acyl group, straight or branched alkoxy group, amidyl group, carboxyl group, alkoxyalkyl group, alkylamino group, alkylsulfonyl group, or sulfonic acid group; or single or multiple quaternary ammonium salts of such compounds.

[0151] In one embodiment, the compositions according to the invention typically contains a corrosion inhibitor. In another embodiment, the composition according to the invention contains a single corrosion inhibitor, which is preferably benzotriazole.

[0152] Alternately, corrosion inhibitors useful in the composition of the invention can be hydroxybenzenes according to the formula: 6

[0153] wherein n=1-4, m=2-5, and each R _m is independently hydrogen, a substituted C ₁ -C ₇ straight, branched or cyclic hydrocarbon group; a substituted acyl group, straight or branched alkoxy group, amidyl group, carboxyl group, alkoxyalkyl group, aklylamino group, alkylsulfonyl group, or sulfonic acid group, or the salt of such compounds. In one embodiment, the corrosion inhibitors can be dihydroxybenzene isomers and/or alkyl substituted dihydroxybenzenes. In this embodiment, the preferred corrosion inhibitors are 1,2-dihydroxybenzene and/or 1,2-dihydroxy-4-tert-butylbenzene.

[0154] Additional corrosion inhibitors as known in the art can also be used in the composition of the present invention. For example, corrosion inhibitors which are substantially metal-ion-free can be utilized, such as thiophenol or its derivatives according to the formula: 7

[0155] where R ₁ is preferably a hydrogen, hydroxyl, or carboxylic acid group; or an ethylenediamine tetracarboxylic acid (EDTC), or a salt thereof, having the formula: 8

[0156] wherein R ₁ , R ₂ , R ₃ and R ₄ can be either H, or NR ₅ R ₆ R ₇ R ₈ , where R ₅ , R ₆ , R ₇ , and R ₈ are each independently hydrogen or a linear or branched C ₁ -C ₆ hydrocarbon, or where two or more of R ₅ , R ₆ , R ₇ , and R ₈ together form a heterocyclic C ₄ -C ₇ ring; wherein R ₉ and R ₁₀ may be independently defined in each repeat unit and each of which are independently hydrogen or a linear or branched C ₁ -C ₆ hydrocarbon, and wherein each of q, r, s, and t is a whole number from 0 to 4 (i.e., when q, r, s, or t=0, there is no atom between the nitrogen and the —COOH group in the formula above). As evident from the above formula, the EDTC can be mono-, di- or tri- substituted rather than tetra-substituted. For example, when each of q, r, s, and t are 1, when each R ₉ and R ₁₀ is a hydrogen, and when each R ₁ , R ₂ , R ₃ and R ₄ are all hydrogens, the EDTC above is ethylenediamine tetraacetic acid (EDTA). Metal salts are not believed to be suitable for use, based upon the understood mechanism of ionic contamination in a microcircuit as caused by cleaning, as the compositions according to the invention are preferably free of metals/metal ions.

[0157] Examples of other corrosion inhibitors include, but are not limited to, nitrate salts of ammonium; hydrocarbon-substituted ammonium nitrate salts; a choline, bischoline, and/or trischoline salt, e.g., such as a hydroxide, a bisulfite, or the like; 2,4-pentandione dioxime; 1,6-dioxaspiro[4,4]nonane 2,7-dione (di-ether); thiourea; ammonium bisulfite; glycerol; sorbitol; gelatine; starch; phosphoric acid; silicic acid; polyethylene oxide; polyethylene imine; and the like; or a combination thereof. Preferably, the corrosion inhibitors are substantially free of metals and/or metal ions.

[0158] In one embodiment, the composition can optionally include at least one two carbon atom linkage alkanolamine compound. The generic two carbon atom linkage alkanolamine compounds suitable for inclusion in the invention have the structural formula, 9

[0159] wherein R ₁ , R ₁ ′, R ₂ , R ₂ ′, and R ₃ are, independently in each case, hydrogen or a linear, branched, or cyclic hydrocarbon containing from 1 to 7 carbon atoms; wherein Z is a group having the formula -(-Q-CR ₁ R ₁ ′—CR ₂ R ₂ ′—) _m —, such that m is a whole number from 0 to 3 (i.e., when m=0, there is no atom between the —CR ₂ R ₂ ′— group and the —OR ₃ group in the formula above), R ₁ , R ₁ ′, R ₂ , and R ₂ ′ may be independently defined in each repeat unit, if m>1, within the parameters set forth for these moieties above, and Q may be independently defined in each repeat unit, if m>1, each Q being independently either —O— or —NR ₃ —; and wherein X and Y are, independently in each case, hydrogen, a C ₁ -C ₇ linear, branched, or cyclic hydrocarbon, or a group having the formula —CR ₁ R ₁ ′—CR ₂ R ₂ ′-Z-F, with F being either —O—R ₃ or —NR ₃ R ₄ , where R ₄ is defined similarly to R ₁ , R ₁ ′, R ₂ , R ₂ ′, and R ₃ above, and with Z, R ₁ , R ₁ ′, R ₂ , R ₂ ′, and R ₃ defined as above, or wherein X and Y are linked together form a nitrogen-containing heterocyclic C ₄ -C ₇ ring.

[0160] Many two-carbon atom linkage alkanolamine compounds have relatively low boiling points and relatively low flash points. The two carbon atom linkage alkanolamine compounds that may be useful in the present invention preferably have relatively high boiling points (e.g., 185° C. or above, preferably 200° C. or above, alternately 215° C. or above) and preferably have relatively high flash points (e.g., 95° C. or above, preferably 100° C. or above, alternately 110° C. or above). Preferred specific examples of such two carbon atom linkage alkanolamine compounds include AEEA and 2-(2-aminoethoxy)ethanol (“DGA”). AEEA, or N-hydroxyethyl-ethylenediamine, is the most preferred of the two carbon atom linkage alkanolamine compounds, though it may be admixed with other two carbon atom linkage alkanolamine compounds to achieve a particular result, such as increased etching or lower cost.

[0161] Examples of other two-carbon atom linkage alkanolamine compounds include, but are in no way limited to, 2-aminoethanol (“monoethanolamine” or “MEA”), 2-(N-methylamino)ethanol (“monomethyl ethanolamine” or “MMEA”), 2-amino-1-propanol (“monoisopropanolamine” or “MIPA”), 2-(N-hydroxyethyl-amino)-ethanol (“diethanolamine” or “DEA”), 2-[(2-aminoethyl)-(2-hydroxyethyl)-amino]-ethanol (“N,N-bis-hydroxyethyl-ethylenediamine”), N,N,N-tris-(2-hydroxyethyl)-ammonia (“triethanolamine” or “TEA”), N-aminoethyl-N′-hydroxyethyl-ethylenediamine, N,N′-dihydroxyethyl-ethylenediamine, 2-[2-(2-aminoethoxy)-ethylamino]-ethanol, 2-[2-(2-aminoethylamino)-ethoxy]-ethanol, 2-[2-(2-aminoethoxy)-ethoxy]-ethanol, tertiarybutyldiethanolamine, isopropanolamine, diisopropanolamine, 3-amino-1-propanol (“n-propanolamine” or “NPA”), isobutanolamine, 2-(2-aminoethoxy)-propanol; 1-hydroxy-2-aminobenzene; or the like, or any combination thereof.

[0162] In one embodiment, the composition can contain a two-carbon atom linkage alkanolamine compound, in which m is greater than or equal to 1. In another embodiment, the composition can contain a two-carbon atom linkage alkanolamine compound, in which m is 1 and R ₁ , R ₁ ′, R ₂ , R ₂ ′, and R ₃ are all hydrogen or a C ₁ -C ₄ linear or branched hydrocarbon. In an alternate embodiment, the composition can contain a two-carbon atom linkage alkanolamine compound, in which: m is 1; R ₁ , R ₁ ′, R ₂ , R ₂ ′, and R ₃ are all hydrogen or a C ₁ -C ₄ linear or branched hydrocarbon; and Q is —NR ₃ . In another alternate embodiment, the composition can contain a two-carbon atom linkage alkanolamine compound, in which: m is 1; R ₁ , R ₁ ′, R ₂ , R ₂ ′, and R ₃ are all hydrogen; X and Y are, independently, hydrogen or a linear or branched C ₁ -C ₄ hydrocarbon; and Q is —NH—, —NCH ₃ —, or —N[(C ₂ -C ₄ ) linear or branched hydrocarbon]-. In an alternate embodiment, the composition may be substantially free from two carbon atom linkage alkanolamine compounds.

[0163] In practice, it appears that, when present, the corrosion inhibitor (particularly in the form of an EDTC, catechol, or gallic acid) enhances the ability of the two carbon atom linkage alkanolamine compound (when present) to clean/polish the substrate. At the same time, when present, the EDTC, catechol, gallic acid, or other corrosion inhibitor can help to prevent attack on the metal or metal alloy substrate, e.g., copper.

[0164] In one embodiment, the composition can contain a quaternary ammonium salt, e.g., as represented by the following formula: 10

[0165] wherein R ₁ , R ₂ , R ₃ , and R ₄ are independently hydrogen; optionally a substituted C ₁ -C ₆ straight, branched or cyclic hydrocarbon group; optionally a substituted acyl group, straight or branched alkoxy group, amidyl group, carboxyl group, alkoxyalkyl group, alkylamino group, or alkylsulfonyl group, sulfonic acid group; or the salt of such compounds; and wherein the [counterion] ⁻ may be a monovalent, divalent, trivalent, or tetravalent anion and is preferably a monovalent anion. In an alternate embodiment, the composition may be substantially free from quaternary ammonium salts.

[0166] Examples of monovalent anions for use as a counterion to a quaternary ammonium salt according to the invention include, but are not limited to, hydroxyl groups, nitrate groups, bisulfite groups, bicarbonate groups, carboxylate groups having structures based on singly de-protonated carboxylic acid groups (e.g., formate, acetate, propionate, butyrate, isobutyrate, benzoate, naphthoate, or the like, or singly de-protonated forms of multiply protic carboxylic acids, such as lactate, ascorbate, glyconate, oxalate, malonate, fumarate, maleate, phthalate, isophthalate, terephthalate, gluconate, succinate, glutarate, tartrate, salicylate, glycerate, citrate, gallate, subgallate, or the like), or other acids listed herein, or the like, or a combination thereof. For a list of pKa's of various carboxylic acids and their relative likelihood of being mono-, di-, or tri-valent anions, see the Table below. 1

[0167] In one embodiment, the composition according to the invention optionally contains a chelating agent. In another embodiment, the composition according to the invention contains a single chelating agent, which is preferably EDTA (or a non-metallic salt thereof), another organic polyacetic acid compound (or a non-metallic salt thereof), gallic acid, or catechol. Catechol has a boiling point of 245° C., and a flash point of 127° C. In another embodiment, the composition according to the invention contains a mixture of two chelating agents, such as catechol and gallic acid. In another embodiment, the composition according to the invention contains a mixture of two chelating agents, preferably catechol and a polyacetic acid such as EDTA, or its corresponding salt. In an alternate embodiment, the composition is substantially free from chelating agents.

[0168] Examples of chelating agents include, but in no way limited to, mono-, di-, or multi- hydroxybenzene-type compounds, e.g., such as catechol, resorcinol, butylated hydroxytoluene (“BHT”), and the like, or a combination thereof. In one embodiment the chelators include three or more carboxylic acid-containing moieties, e.g., such as ethylenediamine tetraacetic acid (“EDTA”), non-metallic EDTA salts, and the like, or a combination thereof Compounds containing a two carboxylic acid moieties, such as citric acid, are less preferred. Compounds containing both hydroxyl and carboxylic acid moieties, e.g., such as gallic acid and the like, are useful in one embodiment. Aromatic compounds containing thiol groups, e.g., such as thiphenol; amino-carboxylic acids; diamines, e.g., such as ethylene diamine; polyalcohols; polyethylene oxide; polyamines; polyimines; or a combination thereof, are useful in one embodiment. In one embodiment, two or more chelating agents can be used in one composition, where the chelating agents are selected from groups described above. Alternately or additionally, some chelating agents are described in U.S. Pat. No. 5,417,877, issued May 23, 1995 to Ward, and in commonly assigned U.S. Pat. No. 5,672,577, issued Sep. 30, 1997 to Lee, the disclosures of each of which are incorporated herein by reference.

[0169] Catechol can, in one embodiment, act as both a chelating agent and as a corrosion inhibitor.

[0170] In one embodiment, the composition according to the invention optionally contains a polar organic solvent. In an alternate embodiment, the compositions is substantially free of polar organic solvent. Examples of polar organic solvents for the composition according to the invention include, but are in no way limited to, dimethyl sulfoxide, ethylene glycol, ethylene glycol alkyl ether, diethylene glycol alkyl ether, triethylene glycol alkyl ether, propylene glycol, propylene glycol alkyl ether, dimethyl sulfoxide, N-substituted pyrrolidone such as N-methyl-2-pyrrolidone (NMP), sulfolanes, dimethylacetamide, and the like, or any combination thereof. Dimethylsulfone, CAS No. 126-33-0, with a boiling point of 237° C., is preferred in some embodiments of the invention. NMP, with a boiling point of 199-202° C. and a flash point of only 96° C., may be useful in some embodiments because of low cost. NMP does, however, tend to lower the flash point of mixtures of the present invention. Similarly, DMSO, with a boiling point of 189° C. and a flash point of only 95° C., is less preferred in some embodiments of the invention. 2,4-dimethylsulfolane, with a boiling point of 280° C. and a flash point of 143° C., is preferred in some embodiments of the invention. Care must be taken because, in the absence of alkanolamines and the like, 2,4-dimethylsulfolane is only slightly miscible with water.

[0171] According to the present invention, amines, particularly alkanolamines and also particularly low molecular weight amines, are separate from, and are not classified as, a polar organic solvent. Other additional polar organic solvents as known in the art, other than those specifically excluded, can also be used in the composition of the present invention. In an alternate embodiment, the composition according to the invention is substantially free from polar organic solvents as defined herein.

[0172] Generally, non-polar organic solvents are not preferred, though high boiling alcohols and the like may be used.

[0173] Organic solvents, including polar organic solvents, that have a boiling point less than about 100° C. are undesirable in the composition according to the invention, as they tend to evaporate over a period of more than about 24-48 hours at operating conditions. Thus, generally the composition according to the invention can be substantially free of organic solvents, particularly that have a boiling point less than about 100° C. It is more preferred that the composition according to the invention be substantially free of organic solvents that have a boiling point less than about 150° C. It is even more preferred that the composition according to the invention be substantially free of organic solvents that have a boiling point less than about 199° C.

[0174] In one embodiment, the composition according to the invention optionally contains an amine compound that is not a hydroxyl-containing amine and is not an alkanolamine. In an alternate embodiment, the composition is substantially free of amines that are not hydroxyl-containing amines and that are not alkanolamines. Examples of such amine compounds include, but are in no way limited to, o-diaminobenzene, p-diaminobenzene, N-(2-aminoethyl)-ethylenediamine (“AEEDA”), piperazine, N-substituted piperazine derivatives, piperidine, N-substituted piperidine derivatives, diethylene triamine, 2-methyleneaminopropylenediamine, hexamthylene tetramine, and the like, or a combination thereof. In a preferred embodiment, when present, the non-hydroxyl-containing amine compound(s) has(have) a boiling point no less than about 100° C., or alternately no less than about 150° C. Amines may increase corrosion of certain sensitive metals. In an alternate embodiment, the composition according to the invention can be substantially free from non-hydroxyl-containing amine compounds, or non-hydroxyl-containing amine compounds having boiling points no less than about 100° C., or alternately no less than about 150° C.

[0175] In one embodiment, the composition according to the invention also contains a surfactant. In an alternate embodiment, the composition is substantially free of surfactant. Examples of surfactants include, but are in no way limited to, sodium laurel sulfate, sodium stearate, and the like, or a combination thereof.

[0176] In one embodiment, the composition according to the invention also contains an additional oxidizing agent (i.e., other than any hydroxylamine, hydroxylamine derivatives, pH-controlling acids/bases, two carbon atom linkage amine compounds, non-hydroxyl-containing amines, quaternary ammonium salts, and/or other components present in the composition that may serve to oxidize at least a portion of one or more of the layers on the substrate). In an alternate embodiment, the composition is substantially free of additional oxidizing agents.

[0177] Examples of additional oxidizing agents include, but are not limited to: acids and/or salts having halide ions, i.e., including ammonium and alkyl substituted ammonium halides; acids and/or salts having halate (e.g., HalO ₄ ^−x ions, where Hal is a halogen atom and (−x) is the ionic charge) ions, i.e., including ammonium and alkyl substituted ammonium halates; acids and/or salts having metalate (e.g., MO ₄ ^−x ions, where M is a metal atom, such as chromium, manganese, copper, gallium, molybdenum, or the like, and wherein (−x) is the ionic charge) ions, i.e., including ammonium and alkyl substituted ammonium metalates; acids and/or salts having borate ions, i.e., including ammonium and alkyl substituted ammonium borates (e.g., sodium borate, potassium borate, iron borate, copper borate, boric acid, or the like, or a combination thereof); acids and/or salts having nitrate ions, i.e., including ammonium and alkyl substituted ammonium nitrates (e.g., ferric nitrate, sodium nitrate, calcium nitrate, copper nitrate, nickel nitrate, aluminum nitrate, potassium nitrate, nitric acid, or the like, or a combination thereof); acids and/or salts having nitrite ions, i.e., including ammonium and alkyl substituted ammonium nitrites (e.g., ferric nitrite, sodium nitrite, calcium nitrite, copper nitrite, nickel nitrite, aluminum nitrite, potassium nitrite, nitrous acid, or the like, or a combination thereof); acids and/or salts having phosphate ions, i.e., including ammonium and alkyl substituted ammonium phosphates (e.g., iron phosphate, sodium phosphate, calcium phosphate, copper phosphate, nickel phosphate, magnesium phosphate, aluminum phosphate, potassium phosphate, phosphoric acid, or the like, or a combination thereof); acids and/or salts having phosphite ions, i.e., including ammonium and alkyl substituted ammonium phosphites (e.g., iron phosphite, sodium phosphite, calcium phosphite, copper phosphite, nickel phosphite, magnesium phosphite, aluminum phosphite, potassium phosphite, phosphorous acid, or the like, or a combination thereof); acids and/or salts having hypophosphite ions, i.e., including ammonium and alkyl substituted ammonium hypophosphites (e.g., iron hypophosphite, sodium hypophosphite, calcium hypophosphite, copper hypophosphite, nickel hypophosphite, magnesium hypophosphite, aluminum hypophosphite, potassium hypophosphite, hypophosphoric acid, or the like, or a combination thereof); acids and/or salts having sulfate ions, i.e., including ammonium and alkyl substituted ammonium sulfates (e.g., iron sulfate, sodium sulfate, calcium sulfate, copper sulfate, nickel sulfate, magnesium sulfate, aluminum sulfate, potassium sulfate, sulfuric acid, or the like, or a combination thereof); acids and/or salts having sulfite ions, i.e., including ammonium and alkyl substituted ammonium sulfites (e.g., iron sulfite, sodium sulfite, calcium sulfite, copper sulfite, nickel sulfite, magnesium sulfite, aluminum sulfite, potassium sulfite, sulfurous acid, or the like, or a combination thereof); acids and/or salts having hyposulfite ions, i.e., including ammonium and alkyl substituted ammonium hyposulfites (e.g., iron hyposulfite, sodium hyposulfite, calcium hyposulfite, copper hyposulfite, nickel hyposulfite, magnesium hyposulfite, aluminum hyposulfite, potassium hyposulfite, hyposulfuric acid, or the like, or a combination thereof); a compound containing at least one oxygen-oxygen bond, but not gaseous O ₂ or O ₃ (e.g., a peroxide such as hydrogen peroxide, benzoyl peroxide, or the like; a peracid such as peracetic acid, periodic acid, perboric acid, perchloric acid, perbromic acid, perchromic acid, or the like; a perhalate such as perchlorate, perbromate, periodate, or the like; a permetalate such as perborate, permanganate, perchromate, or the like; a di-permetalate such as di-perchromate, di-permanganate, or the like; a persulfate; a di-persulfate; a percarbonate, or the like; or a combination thereof); a compound containing at least one nitrogen-nitrogen bond, but not gaseous N ₂ (e.g., hydrazine and/or a hydrazine derivative such as described above, an azo compound such as AIBN, a diazo compound, an azide such as sodium azide, or the like, or a combination thereof); or the like; or a combination thereof.

[0178] In one embodiment, the composition according to the invention also contains an additional non-abrasive additive. These additional additives may be spherical, discotic, elliptical, irregular, or any other shape, dense, porous, hollow, e.g., in the form of a particle, agglomerate, foam, flake, fiber/whisker, or the like, or any combination thereof), but must be substantially non-abrasive to the substrate and/or layer(s) (e.g., metal oxide, metal nitride, etc.) disposed thereon. Examples of additional non-abrasive particulate additives include, but are not limited to: polymeric additives such as rubber particles, polyurethane foams, or the like; sources of carbon such as carbon black particles, mica, or the like; relatively soft metal oxides such as iron oxide or the like; hydrated metal oxides (e.g., metal hydroxides and/or oxide hydroxides) such as aluminum hydroxides and/or oxide hydroxides (e.g., gibbsite, bayerite, nordstrandite, doyleite, boehmite, diaspore, carboirite, rankamite, simpsonite, bahianite, alumotungstite, meixnerite, hydrocalumite, kuzelite, and the like), iron hydroxides and/or oxide hydroxides (e.g., including bemalite, goethite, lepidocrocite, feroxyhyte, ferritungstite, akaganeite, derbylite, tomichite, graeserite, hemolite, kleberite, carmichaelite, yttrocrasite, bamfordite, jamborite, iowaite, muskoxite, montroseite, and the like), manganese hydroxides and/or oxide hydroxides (e.g., including manganite, groutite, feitknechtite, nsutite, janggunite, vemadite, cianciulliite, quenselite, and the like), chromium hydroxides and/or oxide hydroxides (e.g., including woodallite, bracewellite, guyanaite, grimaldiite, and the like), tin hydroxides and/or oxide hydroxide (e.g., hydroromarchite), antimony hydroxides and/or oxide hydroxides (e.g., including partzite, stetefeldtite, romeite, stibiconite, bismutostibiconite, bindheimite, jixianite, scheteligite, brandholzite, bottinoite, cyanophyllite, cualstibite, shakhovite, and the like), niobium hydroxides and/or oxide hydroxides (e.g., including betafite, stibiobetafite, yttrobetafite, plumbobetafite, calciobetafite, pyrochlore, kalipyrochlore, strontiopyrochlore, bariopyrochlore, yttropyrochlore, ceriopyrochlore, plumbopyrochlore, bismutopyrochlore, uranpyrochlore, fersmite, and the like), tantalum hydroxides and/or oxide hydroxides (e.g., including microlite, stannomicrolite, stibiomicrolite, bariomicrolite, parabariomicrolite, plumbomicrolite, bismutomicrolite, uranmicrolite, and the like), calcium hydroxides and/or oxide hydroxides, titanium hydroxides and/or oxide hydroxides (e.g., including portlandite, kassite, kobeite, lucasite, aeschynite, niobo-aeschynite, and the like), or the like, or combinations thereof; relatively soft minerals such as talc, gypsum, magnesium sulfate, or the like; or the like, or combinations thereof. In an alternate embodiment, the composition is substantially free of additional non-abrasive particulate additives.

[0179] Advantageously, the amount of hydroxylamine derivatives (including hydroxylamine, when present) in the composition according to the invention can be from about 0.1% to about 50%, preferably from about 0.2% to about 20%, alternately from about 0.5% to about 10%, for example from about 0.5% to about 5% or from about 5% to about 10%.

[0180] When present, the amount of hydroxylamine in the composition according to the invention can be expressed in a ratio, relative to the amount of hydroxylamine derivative(s) present in the composition according to the invention. In one embodiment, the hydroxylamine:hydroxylamine derivative weight ratio can be from about 1:20 to about 20:1, for example from about 1:20 to about 1:1 or from about 1:1 to about 1:20, alternately from about 1:5 to about 1:1 or from about 1:10 to about 1:2. In another embodiment, the hydroxylamine:hydroxylamine derivative molar ratio can be from about 1:54 to about 8:1, alternately from about 1:54 to about 1:2.7 or from about 1:2.7 to about 8:1, for example from about 1:13.5 to about 1:2.7 or from about 1:2.7 to about 1.9:1.

[0181] Advantageously, the amount of corrosion inhibitor in the composition according to the invention can be from about 0.01% to about 10%, preferably from about 0.01% to about 2%, more preferably from about 0.01% to about 1%, for example, from about 0.01% to about 0.05% or from about 0.01% to about 0.1%, or alternately from about 0.1% to about 1%.

[0182] Advantageously, the amount of water in the composition according to the invention can advantageously be the majority of the composition, e.g., from about 50% to about 99%, preferably from about 60% to about 98%, for example from about 75% to about 97% or from about 65% to about 90%, alternately from about 80% to about 98% or from about 90% to about 99%.

[0183] When present, the amount of acid and/or base added into the composition according to the invention can advantageously be sufficient to adjust the pH of the composition to the desired level. A particular amount of acid and/or base to adjust the pH is not specified herein, although it is generally less than about 5%, for example, less than about 2%, alternately from about 0.01% to about 2% or from about 0.01% to about 1%.

[0184] When present, the amount of two-carbon atom linkage alkanolamine compound in the composition according to the invention can advantageously be from about 0.1% to about 15%, alternately from about 0.01% to about 5%, from about 0.2% to about 10%, from about 0.1% to about 1%, or from about 0.5% to about 5%.

[0185] When present, the amount of chelating agent in the composition according to the invention can advantageously be from about 0.01% to about 15%, for example, from about 0.1% to about 10%, alternately from about 0.01% to about 1%, from about 0.01% to about 0.1%, from about 2% to about 8%, or from about 1% to about 5%.

[0186] When present, the amount of quaternary ammonium salt in the composition according to the invention can advantageously be from about 0.01% to about 15%, for example, from about 0.1% to about 10%, alternately from about 0.01% to about 1%, from about 0.01% to about 0.1%, from about 2% to about 8%, or from about 1% to about 5%.

[0187] When present, the amount of organic solvent in the composition according to the invention can advantageously be from about 0.1% to about 25%, for example from about 0.5% to about 15%, alternately from about 0.1% to about 10% or from about 5% to about 20%.

[0188] When present, the amount of polar organic solvent in the composition according to the invention can advantageously be from about 0.1% to about 20%, for example, from about 0.1% to about 10%, alternately from about 0.5% to about 10%, from about 2% to about 8%, or from about 1% to about 5%.

[0189] When present, the amount of non-hydroxyl-containing amine in the composition according to the invention can advantageously be from about 0.01% to about 15%, for example, from about 0.1% to about 10%, alternately from about 0.01% to about 1%, from about 0.01% to about 0.1%, from about 2% to about 8%, or from about 1% to about 5%.

[0190] When present, the amount of surfactant in the composition according to the invention can advantageously be from about 0.01% to about 10%, for example, from about 0.1% to about 5%, or alternately from about 0.01% to about 1% or from about 1% to about 10%.

[0191] When present, the amount of additional oxidizing agent in the composition according to the invention can advantageously be from about 0.1% to about 10%, for example, from about 0.5% to about 5%, alternately from about 1% to about 10%, from about 2% to about 8%, or from about 1% to about 5%.

[0192] When present, the amount of non-abrasive additives in the composition according to the invention can advantageously be from about 0.1% to about 25%, for example from about 0.5% to about 15%, alternately from about 0.1% to about 10% or from about 5% to about 20%.

[0193] Preferably, all of the compositions according to the invention have very low metal impurity/ion contents, i.e., not more than about 10 ppm total. In a preferred embodiment, the compositions according to the invention have not more than about 5 ppm total metal content, preferably not more than about 1 ppm total metal impurity and metal ion content.

[0194] In a preferred embodiment, the composition according to the invention contains: substantially no abrasive particles, a hydroxylamine derivative, a corrosion inhibitor, water, optionally hydroxylamine, optionally an acid and/or a base (e.g., to adjust pH), optionally a two carbon atom linkage alkanolamine compound, optionally a quaternary ammonium salt, optionally a chelating agent, optionally an organic solvent, optionally a non-hydroxyl-containing amine compound, optionally a surfactant, optionally an additional oxidizing agent, and optionally a non-abrasive additive. In another preferred embodiment, the composition according to the invention can be substantially free of one or more of the following: abrasive particles, hydroxylamine, acid and/or base to adjust pH, two carbon atom linkage alkanolamine compounds, quaternary ammonium salts, chelating agents, organic solvents (polar and/or non-polar), non-hydroxyl-containing amine compounds, surfactants, additional oxidizing agents, and non-abrasive additives.

[0195] While the compositions according to the invention are preferably substantially free of abrasive particles, the processes according to the invention may advantageously include the use of an abrasive (e.g., an abrasive pad or the like), but preferably not abrasive particles.

[0196] In a preferred embodiment, the present invention relates to a process for chemical mechanical polishing of a substrate including: providing a substantially abrasive-free chemical mechanical polishing composition as described above; contacting the chemical mechanical polishing composition with a substrate having a dielectric material surface (e.g., a metal oxide layer), upon which dielectric material a barrier layer is disposed, upon which barrier layer a metal layer is disposed; and chemically mechanically polishing the substrate by contacting the substrate surface with an abrasive polishing pad, preferably at an applied pressure of not more than about 2 psi and by moving the pad in relation to the substrate. In another preferred embodiment, the metal layer includes copper. In an alternate embodiment, the metal layer can include tungsten, aluminum, polysilicon, or the like, or a combination thereof. In another preferred embodiment, the barrier layer can be based on a refractory metal such as tantalum and/or may include a metal nitride (and preferably includes tantalum nitride). In an alternate embodiment, the barrier layer can be titanium-based.

[0197] Advantageously, at least one or more of the following may apply to the process according to the invention: the removal rate during the CMP step of the barrier layer can be greater than about 500 Å/min, less than about 750 Å/min, or both; the removal rate during the CMP step of the dielectric layer can be less than about 10 Å/min, preferably less than about 5 Å/min, for example not more than about 1 Å/min; and the removal rate of the metal layer during the CMP step can be less than about 250 Å/min, greater than about 10 Å/min, or both. In another embodiment, the removal rate of the metal layer during the CMP step can be less than about 500 Å/min, greater than about 50 Å/min, or both.

EXAMPLES

[0198] The following non-limiting examples represent best modes contemplated by the inventors and describe the invention further. In these examples, solution chemistry was tested as follows:

Example 1

[0199] Test: Solutions of ammonium persulfate were prepared and then added to a 5% alumina slurry. The pHs were adjusted with NaOH just before use.

[0200] The CMP experiments were with 10,000 Å tungsten wafers, at 33 rpm and 2 psig. The pad was a Rodell RC 1000 on a Logitech P5M polisher. Base line polishing experiments with only an alumina slurry have determined that there is an 8× to 10× polishing factor between the Logitech and the IPEC/Westech industrial size CMP polisher. 2

[0201] Notice that there appears to be a maximum value at a pH around 7.9.

Example 2

[0202] Test: Mother composition that was tested was composed of ammonium persulfate (APS) with varying concentrations of malonic acid (MA). The pH was adjusted with sodium hydroxide. Ammonium hydroxide will be oxidized to nitrogen and water. 3