Chemical-mechanical planarization composition having PVNO and associated method for use

A composition and associated method for chemical mechanical planarization (or other polishing) are described. The composition contains an abrasive, a dielectric protector comprising a polyvinylpyridine-N-oxide polymer, an oxiding agent, and water. The composition affords minimization of local erosion effects and possesses high selectivities for metal and barrier material removal in relation to dielectric layer materials in metal CMP. The composition is particularly useful in conjunction with the associated method for metal CMP applications (e.g., step 1 copper CMP processes and step 2 copper CMP processes).

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Description
CROSS REFERENCE TO RELATED APPLICATION

The present application is a continuation-in-part of U.S. patent application Ser. No. 10/683,231 filed Oct. 10, 2003.

BACKGROUND OF THE INVENTION

This invention relates generally to the chemical-mechanical polishing (CMP) of metal substrates on semiconductor wafers and slurry compositions therefor. In particular, the present invention relates to a CMP slurry composition which is characterized to afford minimization of local erosion effects and possess high selectivities for removal of metal and barrier layer materials in relation to dielectric layer materials during CMP processing of substrates comprised of metal, barrier layer materials, and dielectric layer materials. This invention is especially useful for copper CMP and most especially for step 1 copper CMP processes and step 2 copper CMP processes.

Chemical mechanical planarization (chemical mechanical polishing, CMP) for planarization of semiconductor substrates is now widely known to those skilled in the art and has been described in numerous patents and open literature publications. Some introductory references on CMP are as follows: “Polishing Surfaces for Integrated Circuits”, by B. L. Mueller and J. S. Steckenrider, Chemtech, February, 1998, pages 38-46; H. Landis et al., Thin Solids Films, 220 (1992), page 1; and “Chemical-Mechanical Polish” by G. B. Shinn et al., Chapter 15, pages 415-460, in Handbook of Semiconductor Manufacturing Technology, editors: Y. Nishi and R. Doering, Marcel Dekker, New York City (2000).

In a typical CMP process, a substrate (e.g., a wafer) is placed in contact with a rotating polishing pad attached to a platen. A CMP slurry, typically an abrasive and chemically reactive mixture, is supplied to the pad during CMP processing of the substrate. During the CMP process, the pad (fixed to the platen) and substrate are rotated while a wafer carrier system or polishing head applies pressure (downward force) against the substrate. The slurry accomplishes the planarization (polishing) process by chemically and mechanically interacting with the substrate film being planarized due to the effect of the rotational movement of the pad relative to the substrate. Polishing is continued in this manner until the desired film on the substrate is removed with the usual objective being to effectively planarize the substrate. Typically metal CMP slurries contain an abrasive material, such as silica or alumina, suspended in an oxidizing, aqueous medium.

Silicon based semiconductor devices, such as integrated circuits (ICs), typically include a dielectric layer. Multilevel circuit traces, typically formed from aluminum or an aluminum alloy or copper, are patterned onto the dielectric layer substrate.

CMP processing is often employed to remove and planarize excess metal at different stages of semiconductor manufacturing. Various metals and metal alloys have been used at different stages of semiconductor manufacturing, including tungsten, aluminum, copper, tantalum, tantalum nitride, titanium, titanium nitride, ruthenium, platinum, iridium, and combinations thereof. For example, one way to fabricate a multilevel copper interconnect or planar copper circuit traces on a dielectric substrate is referred to as the damascene process. In a semiconductor manufacturing process typically used to form a multilevel copper interconnect, metallized copper lines or copper vias are formed by electrochemical metal deposition followed by copper CMP processing. In a typical process, the interlevel dielectric (ILD) surface is patterned by a conventional dry etch process to form vias and trenches for vertical and horizontal interconnects and make connection to the sublayer interconnect structures. The patterned ILD surface is coated with an adhesion-promoting layer such as titanium or tantalum and/or a diffusion barrier layer such as titanium nitride or tantalum nitride over the ILD surface and into the etched trenches and vias. The adhesion-promoting layer and/or the diffusion barrier layer is then overcoated with copper, for example, by a seed copper layer and followed by an electrochemically deposited copper layer. Electro-deposition is continued until the structures are filled with the deposited metal. Finally, CMP processing is used to remove the copper overlayer, adhesion-promoting layer, and/or diffusion barrier layer, until a planarized surface with exposed elevated portions of the dielectric (silicon dioxide and/or low-k) surface is obtained. The vias and trenches remain filled with electrically conductive copper forming the circuit interconnects. The adhesion-promoting layer plus diffusion barrier layer is typically collectively referred to as the “barrier layer.”

A multi-step copper CMP process may be employed involving the initial removal and planarization of the copper overburden, referred to as a step 1 copper CMP process, followed by a barrier layer CMP process. The barrier layer CMP process is frequently referred to as a barrier or step 2 copper CMP process. The ratio of the removal rate of copper to the removal rate of dielectric base is called the “selectivity” for removal of copper in relation to dielectric during CMP processing of substrates comprised of copper, barrier layer materials, and dielectric material. The ratio of the removal rate of copper to the removal rate of barrier layer materials is called the “selectivity” for removal of copper in relation to barrier layer materials during CMP processing of substrates comprised of copper, barrier layer materials, and dielectric materials. Barrier layer materials include tantalum, tantalum nitride, tungsten, noble metals such as ruthenium and ruthenium oxide, and combinations thereof.

When CMP slurries over-polish copper layers they may create a depression or “dishing” effect in the copper vias and trenches. This feature distortion is unacceptable due to lithographic and other constraints in semiconductor manufacturing. Another feature distortion that is unsuitable for semiconductor manufacturing is called “erosion.” Erosion is the topography difference between a field of dielectric and a dense array of copper vias or trenches. In CMP, the materials in the dense array may be removed or eroded at a faster rate than the surrounding field of dielectric. This causes a topography difference between the field of dielectric and the dense copper array.

A typically used CMP slurry has two actions, a chemical component and a mechanical component. An important consideration in slurry selection is “passive etch rate.” The passive etch rate is the rate at which copper is dissolved by the chemical component alone and should be significantly lower than the removal rate when both the chemical component and the mechanical component are involved. A large passive etch rate leads to dishing of the copper trenches and copper vias, and thus, preferably, the passive etch rate is less than 10 nanometers per minute.

A number of systems for CMP of copper have been disclosed. A few illustrative examples are listed next. Kumar et al. in an article entitled “Chemical-Mechanical Polishing of Copper in Glycerol Based Slurries” (Materials Research Society Symposium Proceedings, 1996) disclose a slurry that contains glycerol and abrasive alumina particles. An article by Gutmann et al. entitled “Chemical-Mechanical Polishing of Copper with Oxide and Polymer Interlevel Dielectrics” (Thin Solid Films, 1995) discloses slurries based on either ammonium hydroxide or nitric acid that may contain benzotriazole (BTA) as an inhibitor of copper dissolution. Luo et al. in an article entitled “Stabilization of Alumina Slurry for Chemical-Mechanical Polishing of Copper” (Langmuir, 1996) discloses alumina-ferric nitrate slurries that contain polymeric surfactants and BTA. Carpio et al. in an article entitled “Initial Study on Copper CMP Slurry Chemistries” (Thin Solid Films, 1995) disclose slurries that contain either alumina or silicon particles, nitric acid or ammonium hydroxide, with hydrogen peroxide or potassium permanganate as an oxidizer.

In relation to copper CMP, the current state of this technology involves use of a two-step process to achieve local and global planarization in the production of IC chips. During step 1 of a copper CMP process, the overburden copper is removed. Then step 2 of the copper CMP process follows to remove the barrier layer materials and achieve both local and global planarization. Generally, after removal of overburden copper in step 1, polished wafer surfaces have non-uniform local and global planarity due to differences in the step heights at various locations of the wafer surfaces. Low density features tend to have higher copper step heights whereas high density features tend to have low step heights. Due to differences in the step heights after step 1, selective slurries are highly desirable for step 2 copper CMP for the selective removal of barrier layer materials in relation to copper and for the selective removal of dielectric materials in relation to copper.

There are a number of theories as to the mechanism for chemical-mechanical polishing of copper. An article by Zeidler et al. (Microelectronic Engineering, 1997) proposes that the chemical component forms a passivation layer on the copper changing the copper to a copper oxide. The copper oxide has different mechanical properties, such as density and hardness, than metallic copper and passivation changes the polishing rate of the abrasive portion. The above article by Gutmann et al. discloses that the mechanical component abrades elevated portions of copper and the chemical component then dissolves the abraded material. The chemical component also passivates recessed copper areas minimizing dissolution of those portions.

These are two general types of layers that can be polished. The first layer is interlayer dielectrics (ILD), such as silicon oxide, silicon nitride, and low-k films including carbon-doped oxides. The second layer is metal layers such as tungsten, copper, aluminum, etc., which are used to connect the active devices.

In the case of CMP of metals, the chemical action is generally considered to take one of two forms. In the first mechanism, the chemicals in the solution react with the metal layer to continuously form an oxide layer on the surface of the metal. This generally requires the addition of an oxidizer to the solution such as hydrogen peroxide, ferric nitrate, etc. Then the mechanical abrasive action of the particles continuously and simultaneously removes this oxide layer. A judicious balance of these two processes obtains optimum results in terms of removal rate and polished surface quality.

In the second mechanism, no protective oxide layer is formed. Instead, the constituents in the solution chemically attack and dissolve the metal, while the mechanical action is largely one of mechanically enhancing the dissolution rate by such processes as continuously exposing more surface area to chemical attack, raising the local temperature (which increases the dissolution rate) by the friction between the particles and the metal and enhancing the diffusion of reactants and products to and away from the surface by mixing and by reducing the thickness of the boundary layer.

While prior art CMP systems are capable of removing a copper overlayer from a interlayer dielectric substrate, the systems do not satisfy the rigorous demands of the semiconductor industry. These requirements can be summarized as follows. First, there is a need for high removal rates of copper to satisfy throughput demands. Secondly, there must be excellent topography uniformity across the substrate. Finally, the CMP method must minimize local dishing and erosion effects to satisfy ever increasing lithographic demands.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, the invention is a step 2 copper chemical-mechanical planarization composition comprising:

    • a) an abrasive;
    • b) a polyvinylpyridine-N-oxide polymer as protector of a dielectric;
    • c) an oxidizing agent; and
    • d) water.

In another embodiment, the invention is a step 1 copper chemical-mechanical planarization composition comprising:

    • a) an abrasive;
    • b) a polyvinylpyridine-N-oxide polymer as protector of a dielectric;
    • c) an oxidizing agent; and
    • d) water.

In additional embodiments, the invention is a method of step 1 or step 2 chemical-mechanical planarization comprising the steps of:

    • A) placing a substrate comprising copper, at least one dielectric material and at least one barrier material in contact with a polishing pad;
    • B) delivering a chemical-mechanical planarization composition comprising a) an abrasive; b) a polyvinylpyridine-N-oxide polymer; c) an oxidizing agent; and d) water; and
    • C) planarizing the substrate with the polishing composition.

BRIEF DESCRIPTION OF THE DRAWING

The drawing is a graph showing the Effect of PVNO:Silica Ratio on the Percent Reduction of PETEOS Blanket Wafer Removal Rates in Relation to the Relevant Comparative Example.

DETAILED DESCRIPTION OF THE INVENTION

It has been found that CMP polishing compositions comprising an abrasive, a polyvinylpyridine-N-oxide, an oxidizing agent, and water possess high selectivities for metal and barrier layer material (e.g., tantalum) removal in relation to dielectric materials (e.g., PETEOS) removal during CMP processing. Consequently these polishing compositions are particularly useful in copper CMP processing (e.g., step 1 copper CMP and step 2 copper CMP). Optionally, other additives may be included.

Both standard (unmodified) abrasives and surface-modified abrasives can be employed in this invention. Suitable unmodified abrasives include, but are not limited to, silica, alumina, titania, zirconia, germania, ceria, and co-formed products thereof, and mixtures thereof. A surface-modified abrasive obtained by treatment of an unmodified abrasive (e.g., silica) with an inorganic or organometallic compound can also be employed in this invention. Suitable inorganic compounds for modification include boric acid, sodium aluminate, and potassium aluminate. Suitable organometallic compounds for modification include aluminum acetate, aluminum formate, and aluminum propionate. Suitable abrasives include, but are not limited to, colloidal products, fumed products, and mixtures thereof. Some specific examples of surface modified abrasives are modification of silica with boric acid to give boron surface-modified silica and modification of silica with sodium aluminate or potassium aluminate to give aluminate surface-modified silica.

Silica and surface-modified silica are a preferred abrasive material used in the present invention. The silica may be, for example, colloidal silica, fumed silica and other silica dispersions; however, the preferred silica is colloidal silica or surface-modified colloidal silica.

The abrasive is present in the slurry in a concentration of about 0.001 weight % to about 30 weight % of the total weight of the slurry. In one embodiment, the abrasive is present in a concentration of about 1 weight % to about 20 weight % of the total weight of the slurry. In another embodiment, the abrasive is present in a concentration of about 0.01 weight % to about 5 weight % of the total weight of the slurry.

The polyvinylpyridine-N-oxide polymer in this invention can be unsubstituted (i.e., this being the parent polymer) or substituted with one or more substituents. Suitable substituents include, but are not limited to, hydroxyl, fluoro, chloro, bromo, iodo, amino, carboxylic, amido, ester, and alkoxy functional groups. In addition to the homopolymer polyvinylpyridine-N-oxide, the polymer in this invention can also be a copolymer or block copolymer of polyvinylpyridine-N-oxide with another polymer, such as polyvinylpyridine. In one embodiment, the polyvinylpyridine-N-oxide polymer in the compositions of this invention is present in the slurry at a weight percent level ranging from about 0.05 weight % to about 3 weight %. In one embodiment, the polyvinylpyridine-N-oxide polymer is present in a concentration of about 0.05 weight % to about 3 weight % of the total weight of the slurry and the PVNO:Abrasive ratio is greater than 0.05. In another embodiment, the polyvinylpyridine-N-oxide polymer is present in a concentration of about 0.01 weight % to about 0.75 weight % of the total weight of the slurry. In yet another embodiment, the polyvinylpyridine-N-oxide polymer is present in a concentration of about 0.01 weight % to about 0.75 weight % of the total weight of the slurry and the polyvinylpyridine-N-oxide polymer (PVNO):Abrasive ratio is greater than 0.05. In various embodiments of this invention, the polyvinylpyridine-N-oxide polymer is present in an amount sufficient to protect the dielectric. In the majority of embodiments of this invention, the polyvinylpyridine-N-oxide polymer is solubilized and/or dispersed in water. The molecular weight of the polyvinylpyridine-N-oxide polymer in this invention is not limited but generally ranges, as a number average molecular weight, from about 1,000 to about 1 million. Preferably, the number average molecular weight ranges from about 25,000 Daltons to about 250,000 Daltons and more preferably is about 50,000 Daltons. Oligomers and low molecular weight polymers are included within the broad definition of the polyvinylpyridine-N-oxide polymer in this invention.

The oxidizing agent can be any suitable oxidizing agent. Suitable oxidizing agents include, for example, one or more per-compounds, which comprise at least one peroxy group (—O—O—). Suitable per-compounds include, for example, peroxides, persulfates (e.g., monopersulfates and dipersulfates), percarbonates, and acids thereof, and salts thereof, and mixtures thereof. Other suitable oxidizing agents include, for example, oxidized halides (e.g., chlorates, bromates, iodates, perchlorates, perbromates, periodates, and acids thereof, and mixtures thereof, and the like), perboric acid, perborates, percarbonates, peroxyacids (e.g., peracetic acid, perbenzoic acid, m-chloroperbenzoic acid, salts thereof, mixtures thereof, and the like), permanganates, chromates, cerium compounds, ferricyanides (e.g., potassium ferricyanide), mixtures thereof, and the like. Preferred oxidizing agents include, for example, hydrogen peroxide, urea-hydrogen peroxide, sodium peroxide, benzyl peroxide, di-t-butyl peroxide, peracetic acid, monopersulfuric acid, dipersulfuric acid, iodic acid, and salts thereof, and mixtures thereof. The oxidizing agent in the compositions of this invention is present in the slurry in a concentration of about 0.02 weight % to about 10 weight %. In one embodiment, the oxidizing agent is present in a concentration of about 0.05 weight % to about 5 weight % of the total weight of the slurry.

Hydrogen peroxide (H2O2) is used as a preferred oxidizing agent. Preferably the concentration of the H2O2 is from about 0.05 weight % to about 6 weight % of the total weight of the slurry.

Other chemicals that may be added to the CMP slurry composition include, for example, water-miscible solvents, surfactants, pH adjusting agents, acids, corrosion inhibitors, fluorine-containing compounds, chelating agents, non-polymeric nitrogen-containing compounds, and salts.

Suitable water-miscible solvents that may be added to the slurry composition include, for example, ethyl acetate, methanol, ethanol, propanol, isopropanol, butanol, glycerol, ethylene glycol, and propylene glycol, and mixtures thereof. The water-miscible solvents may be present in the slurry composition in a concentration of about 0 weight % to about 4 weight % in one embodiment, of about 0.1 weight % to about 2.0 weight % in another embodiment, and, in a concentration of about 0.5 weight % to about 1.0 weight % in yet another embodiment; each of these weight % values is based on the total weight of the slurry. The preferred types of water-miscible solvents are isopropanol, butanol, and glycerol.

Suitable surfactant compounds that may be added to the slurry composition include, for example, any of the numerous nonionic, anionic, cationic or amphoteric surfactants known to those skilled in the art. The surfactant compounds may be present in the slurry composition in a concentration of about 0 weight % to about 1 weight % in one embodiment, of about 0.0005 weight % to about 1 weight % in another embodiment, and, in a concentration of about 0.001 weight % to about 0.5 weight % in yet another embodiment; each of these weight % values is based on the total weight of the slurry. The preferred types of surfactants are nonionic, anionic, or mixtures thereof and are most preferably present in a concentration of about 10 ppm to about 1000 ppm of the total weight of the slurry. Nonionic surfactants are most preferred. A preferred nonionic surfactant is Surfynol® 104E, which is a 50:50 weight percent mixture of 2,4,7,9-tetramethyl-5-decyn-4,7-diol and ethylene glycol (Air Products and Chemicals, Inc. Allentown, Pa.).

The pH-adjusting agent is used to improve the stability of the polishing composition, to improve the safety in use or to meet the requirements of various regulations. As a pH-adjusting agent to be used to lower the pH of the polishing composition of the present invention, hydrochloric acid, nitric acid, sulfuric acid, chloroacetic acid, tartaric acid, succinic acid, citric acid, malic acid, malonic acid, various fatty acids, various polycarboxylic acids may be employed. On the other hand, as a pH-adjusting agent to be used for the purpose of raising the pH, potassium hydroxide, sodium hydroxide, ammonia, tetramethylammonium hydroxide, ethylenediamine, piperazine, polyethyleneimine, etc., may be employed. The polishing composition of the present invention is not particularly limited with respect to the pH, but it is usually adjusted to pH 5 to 11.

In metal CMP applications, compositions having acidic or alkaline pH values are generally preferred according to this invention. In this case, a suitable slurry pH is from about 5 to about 11. In one embodiment, a suitable slurry pH is from about 6 to about 10. In another embodiment, a suitable slurry pH is from about 7 to about 9.

Other suitable acid compounds that may be added (in place of or in addition to the pH-adjusting acids mentioned supra) to the slurry composition include, but are not limited to, formic acid, acetic acid, propanoic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, lactic acid, hydrochloric acid, nitric acid, phosphoric acid, sulfuric acid, hydrofluoric acid, malic acid, tartaric acid, gluconic acid, citric acid, phthalic acid, pyrocatechoic acid, pyrogallol carboxylic acid, gallic acid, tannic acid, and mixtures thereof. These acid compounds may be present in the slurry composition in a concentration of about 0 weight % to about 5 weight % of the total weight of the slurry.

Suitable corrosion inhibitors that may be added to the slurry composition include, for example, 1,2,4-triazole, benzotriazole, 6-tolylytriazole, tolyltriazole derivatives, 1-(2,3-dicarboxypropyl)benzotriazole, branched-alkylphenol-substituted-benzotriazole compounds, TINUVIN® 99-2, TINUVIN® 109, TINUVIN® 213, TINUVIN® 234, TINUVIN® 326, TINUVIN® 328, TINUVIN® 329, TINUVIN® 384-2, N-acyl-N-hydrocarbonoxyalkyl aspartic acid compounds, and mixtures thereof. The corrosion inhibitor may be present in the slurry in a concentration of about 0 ppm to about 4000 ppm in an embodiment, from about 10 ppm to about 4000 ppm in another embodiment, and from about 50 ppm to about 2000 ppm in yet another embodiment, all based on the total weight of the slurry. Preferred corrosion inhibitors are 1,2,4-triazole, TINUVIN® 109, TINUVIN® 328, TINUVIN® 329, CDX2128 and CDX2165. CDX2128 and CDX2165 are supplied by King Industries, and are preferably present in a concentration of about 50 ppm to about 1000 ppm of the total weight of the slurry. TINUVIN® 109, TINUVIN® 328, and TINUVIN® 329 are supplied by Ciba Specialty Chemicals Corporation, and are preferably present in a concentration of about 20 ppm to about 500 ppm of the total weight of the slurry.

Carboxylic acids, if added, may also impart corrosion inhibition properties to the slurry composition.

To increase the selectivity of tantalum and tantalum compounds relative to silicon dioxide, fluorine-containing compounds may be added to the slurry composition. Suitable fluorine-containing compounds include, for example, hydrogen fluoride, perfluoric acid, alkali metal fluoride salt, alkaline earth metal fluoride salt, ammonium fluoride, tetramethylammonium fluoride, ammonium bifluoride, ethylenediammonium difluoride, diethylenetriammonium trifluoride, and mixtures thereof. The fluorine-containing compounds may be present in the slurry composition in a concentration of about 0 weight % to about 5 weight % in an embodiment, preferably from about 0.65 weight % to about 5 weight % in another embodiment, from about 0.50 weight % to about 2.0 weight % in yet another embodiment, all based on the total weight of the slurry. A suitable fluorine-containing compound is ammonium fluoride.

Suitable chelating agents that may be added to the slurry composition include, but are not limited to, ethylenediaminetetracetic acid (EDTA), N-hydroxyethylethylenediaminetriacetic acid (NHEDTA), nitrilotriacetic acid (NTA), diethylenetriaminepentacetic acid (DPTA), ethanoldiglycinate, glycine, tricine, citric acid, and mixtures thereof. The chelating agents may be present in the slurry composition in a concentration of about 0 weight % to about 3 weight % in one embodiment, and in a concentration of about 0.1 weight % to about 2.0 weight % in another embodiment based on the total weight of the slurry. Preferred chelating agents are glycine, tricine, citric acid and EDTA. When present, a chelating agent is usually present in a concentration of about 0.1 weight % to about 2.0 weight % of the total weight of the slurry.

Suitable non-polymeric nitrogen-containing compounds (amines, hydroxides, etc.) that may be added to the slurry composition include, for example, ammonium hydroxide, hydroxylamine, monoethanolamine, diethanolamine, triethanolamine, diethyleneglycolamine, N-hydroxylethylpiperazine, and mixtures thereof. These non-polymeric nitrogen-containing compounds may be present in the slurry composition in a concentration of about 0 weight % to about 1 weight %, and, if present, are normally present at a level of about 0.01 weight % to about 0.20 weight % of the total weight of the slurry. A preferred non-polymeric nitrogen-containing compound is ammonium hydroxide and is most preferably present in a concentration of about 0.01 weight % to about 0.1 weight % of the total weight of the slurry.

Suitable salts that optionally may be added to the slurry composition include, for example, ammonium persulfate, potassium persulfate, potassium sulfite, potassium carbonate, ammonium nitrate, potassium hydrogen phthalate, hydroxylamine sulfate, and mixtures thereof. The salts may be present in the slurry composition in a concentration of about 0 weight % to about 10 weight %, and, if present, are normally present at a level of about 0.02 weight % to about 5 weight % of the total weight of the slurry.

Still other chemicals that can be added to the slurry compositions are biological agents such as bactericides, biocides and fungicides especially if the pH is around about 6 to 9. Suitable biocides, include, but are not limited to, 1,2-benzisothiazolin-3-one; 2(hydroxymethyl)amino ethanol; 1,3-dihydroxymethyl-5,5-dimethylhydantoin; 1-hydroxymethyl-5,5-dimethylhydantion; 3-iodo-2-propynyl-butylcarbamate; glutaraldehyde; 1,2-dibromo-2,4-dicyanobutane; 5-chloro-2-methyl-4-isothiazoline-3-one; 2-methyl-4-isothiazolin-3-one; and mixtures thereof. Preferred biocides are isothiazolines and benzisothiazolines. When present, a biocide is usually present in a concentration of about 0.001 weight % to about 0.1 weight % of the total weight of the slurry.

Associated Methods

The associated methods of this invention entail use of the aforementioned composition (as disclosed supra) for chemical mechanical planarization of substrates comprised of metals and dielectric materials. In the methods, a substrate (e.g., a wafer) is placed face-down on a polishing pad which is fixedly attached to a rotatable platen of a CMP polisher. In this manner, the substrate to be polished and planarized is placed in direct contact with the polishing pad. A wafer carrier system or polishing head is used to hold the substrate in place and to apply a downward pressure against the backside of the substrate during CMP processing while the platen and the substrate are rotated. The polishing composition (slurry) is applied (usually continuously) on the pad during CMP processing to effect the removal of material to planarize the substrate. Since the associated methods of this invention employ the compositions described herein, the ranges (e.g., pH, component levels) described for composition embodiments also apply to corresponding method embodiments.

The composition and associated methods of this invention are effective for CMP of a wide variety of substrates, including substrates having dielectric portions that comprise materials having dielectric constants less than 3.3 (low-k materials). Suitable low-k films in substrates include, but are not limited to, organic polymers, carbon-doped oxides, fluorinated silicon glass (FSG), inorganic porous oxide-like materials, and hybrid organic-inorganic materials. Representative low-k materials and deposition methods for these materials are summarized below.

Deposition Vendor Trade Name Method Material Air Products and Chemicals MesoElk ® Spin-on Hybrid organic-inorganic Applied Materials Black Diamond CVD Carbon-doped oxide Dow Chemical SiLK ™, Porous SiLK ™ Spin-on Organic polymer Honeywell Electronic Materials NANOGLASS ® E Spin-on Inorganic oxide-like Novellus Systems CORAL ® PECVD Carbon-doped oxide
PECVD = Plasma enhanced chemical vapor deposition

CVD = chemical vapor deposition

Similarly, the composition and associated methods of this invention are effective for CMP of substrates comprised of various metals, including, but not limited to, tantalum, titanium, tungsten, copper, and noble metals. The composition and associated methods of this invention are particularly useful and preferred for copper CMP, and afford very high selectivities for removal of copper in relation to dielectric materials (as illustrated in the examples) and high selectivities for removal of barrier layer materials in relation to dielectric materials (as illustrated in the examples).

While not being bound by any particular theory, the inventor(s) believes that the following considerations may explain why a polishing composition comprising a) an abrasive, b) a polyvinylpyridine-N-oxide, abbreviated as PVNO, polymer, c) an oxidizing agent, and d) water exhibits high “metal to dielectric selectivity” and “barrier layer material to dielectric selectivity” in CMP processing. Under near neutral pH polishing conditions in a step 1 copper CMP slurry and basic pH polishing conditions in a step 2 copper CMP slurry, a dielectric layer (e.g., PETEOS or low-K dielectric) develops a negative charge, which drives the counter positive ions (e.g., ammonium ions in the examples below as the pH was adjusted with ammonium hydroxide) to self-assemble on the dielectric surface. The oxygen attached to the aromatic nitrogen in the six-membered ring of the PVNO molecule attaches itself to the ionic double layer of the dielectric layer, thus protecting the dielectric oxide layer.

The present invention is further demonstrated by the examples below.

GLOSSARY

Components

A) PVNO compounds: The polyvinylpyridine-N-oxide polymer (PVNO) in this invention can be unsubstituted (i.e., this being the parent polymer) or substituted with one or more substituents. Suitable substituents include, but are not limited to, hydroxyl, fluoro, chloro, bromo, iodo, amino, carboxylic, amido, ester, and alkoxy functional groups. In addition to the homopolymer polyvinylpyridine-N-oxide, the polymer in this invention can also be a copolymer or block copolymer of polyvinylpyridine-N-oxide with another polymer, such as polyvinylpyridine.

B) Other co-additives with PVNO compounds in the polishing compositions: A list of other additives used in the polishing formulations is summarized below:

  • 1) Ammonium Fluoride: a 40 weight % solution, GEM Microelectronic Materials L.L.C., 2885 N. Nevada St., Chandler, Ariz. 85225.
  • 2) Ammonium Hydroxide: a 29 weight % solution, Air Products and Chemicals, Inc., 7201 Hamilton Blvd. Allentown, Pa. 18195-1501.
  • 3) Boron surface-modified colloidal silica: prepared from Syton® HT-50 colloidal silica, DuPont Air Products NanoMaterials L.L.C., 2507 West Erie Drive, Tempe, Ariz. 85282.
  • 4) CDX2128: King Industries, Inc., Science Road, Norwalk, Conn. 06852.
  • 5) CDX2165: King Industries, Inc., Science Road, Norwalk, Conn. 06852.
  • 6) Citric Acid: Aldrich Chemical Company, Inc, 1001 West St. Paul, Milwaukee, Wis. 53233.
  • 7) CoppeReady® Cu300: DuPont Air Products NanoMaterials L.L.C., 2507 West Erie Drive, Tempe, Ariz. 85282.
  • 8) Hydrogen Peroxide: a 30 weight % solution, Air Products and Chemicals, Inc., 7201 Hamilton Blvd. Allentown, Pa. 18195-1501.
  • 9) Potassium Hydroxide: Aldrich Chemical Company, Inc, 1001 West St. Paul, Milwaukee, Wis. 53233.
  • 10) NAC532: aluminate surface-modified silica, DuPont Air Products NanoMaterials L.L.C., 2507 West Erie Drive, Tempe, Ariz., 85282.
  • 11) Potassium-stabilized colloidal silica: DuPont Air Products NanoMaterials L.L.C., 2507 West Erie Drive, Tempe, Ariz. 85282 (an approximately 30 weight % potassium-stabilized dispersion in water with a particle size of 50-60 nanometers as measured by Capillary Hydro-Dynamic Flow using a Matec Applied Sciences model number CHDF 2000 instrument.)
  • 12) Surfynol® 104E: a 50:50 mixture by weight of 2,4,7,9-tetramethyl-5-decyn-4,7-diol and ethylene glycol (solvent), Air Products and Chemicals, Inc., 7201 Hamilton Blvd. Allentown, Pa. 18195-1501.
  • 13) Zonyl® FSN: a non-ionic fluoroethoxylated alcohol surfactant, manufactured by E.I. DuPont de Nemours, Inc., 1007 Market Street, Wilmington, Del. 19898.

C) General

  • CDX2128 Corrosion inhibitor—a N-acyl-N-hydrocarbonoxyalkyl aspartic acid compound, which is a water soluble amino acid derivative (King Industries, Inc., Norwalk, Conn.)
  • CDX2165 Corrosion inhibitor—a tolyltriazole derivative (King Industries, Inc., Norwalk, Conn.)
  • S104E Surfynol® 104E—a 50:50 mixture by weight of 2,4,7,9-tetramethyl-5-decyn-4,7-diol and ethylene glycol (solvent), Air Products and Chemicals, Inc., Allentown, Pa.
  • PETEOS Plasma enhanced deposition of tetraethoxy silane; a dielectric oxide layer.
  • Pattern Wafers MIT 854-type mask wafers were procured from Advantiv Technologies, Inc.; 5000 Hopyard Road, Suite 318, Pleasantan, Calif. 94588 for characterizing the impact of slurry formulations on their planarity response. The product identification of the wafers used for these characterizations was CMP431. A description of these wafers includes 0.25 μm trench (M1) etched through 5 KÅ PETEOS to 1 KÅ PE-SiN over 5.5 KÅ oxide 250 Ta/1 KÅ Cu seed, 10 KÅ CuE fill (annealed). A detailed description of the MIT 854 mask can be obtained from the following document: “MIT/Sematech 854 AZ Copper on Low-K Chemical Mechanical Polishing (CMP) Characterization Test Chip” obtained from International Sematech, Inc.
  • Planarity: Planarity refers to terms such as dishing and erosion which are measured on patterned wafers such as MIT 854 mask. Layout of the features is available in the publication from Sematech. Erosion typically is measured on 9/1 or 0.25/0.25 features. A 100/100 feature implies a feature with an array of 100 μm Cu trenches (“lines”) patterned at a pitch of 200 μm, etched and then electrochemically plated. Thus, the center of one 100 μm Cu line is separated from the next by 200 μm leaving a 100 μm space of either PETEOS or Ta over PETEOS or Cu over Ta over PETEOS between two 100 μm Cu lines. Similarly, a 9/1 feature implies a feature with 9 μm Cu lines separated by 1 μm of space, and a pitch of 10 μm between two 9 μm Cu lines. A 0.25/0.25 feature implies 0.25 μm Cu lines separated by 0.25 μm space, and a pitch of 0.5 μm between two 0.25 μm Cu lines.
  • Blanket Wafers: Blanket wafers are those that have typically one type of surface prepared for polishing experiments. These are either electrochemically deposited copper, PVD tantalum, tantalum nitride, or PETEOS. The blanket wafers used in this work were purchased from Silicon Valley Microelectronics, 1150 Campbell Ave, CA, 95126. The film thickness specifications are summarized below.
  • IC1010™ Pad Rohm and Haas Electronic Materials IC1010™ pads were used for step 1 copper CMP. The IC1010™ pad consists of a rigid microporous polyurethane with a radial grooving pattern top pad and a Suba™ IV impregnated felt sub-pad. Rohm and Haas Electronic Materials is based in Newark, Del.
  • Politex® Pad Rohm and Haas Electronic Materials Politex® pads were used for step 2 copper CMP. Rohm and Haas Electronic Materials is based in Newark, Del.
  • PVNO Polyvinylpyridine-N-oxide (Reilly Industries, Inc., 300 North Meridian Street, Suite 1500, Indianapolis, Ind. 46204.); CAS # 58984-27-3
  • PARAMETERS
    • Å: angstrom(s)—a unit of length
    • CMP: chemical mechanical planarization, or chemical mechanical polishing
    • min: minute(s)
    • ml: milliliter(s)
    • mV: millivolt(s)
    • psi: pounds per square inch
    • rpm: revolution(s) per minute
  • PVNO:Abrasive The ratio of the amount of PVNO in the slurry to the amount of Ratio abrasive or surface-modified abrasive in the slurry, both expressed as weight %.
  • PVNO:Silica Ratio The ratio of the amount of PVNO in the slurry to the amount of silica or surface-modified silica in the slurry, both expressed as weight %.
  • Ta:PETEOS Sel
    • Tantalum:PETEOS Selectivity—the ratio of the amount of tantalum removed to the amount of PETEOS removed during CMP experiments using blanket wafers under identical conditions.
  • Ta:Cu Sel Tantalum:Copper Selectivity—the ratio of the amount of tantalum removed to the amount of copper removed during CMP experiments using blanket wafers under identical conditions.
  • TaN:PETEOS Sel Tantalum nitride:PETEOS Selectivity—the ratio of the amount of tantalum nitride removed to the amount of PETEOS removed during CMP experiments using blanket wafers under identical conditions.
  • TaN:Cu Sel Tantalum nitride:Copper Selectivity—the ratio of the amount of tantalum nitride removed to the amount of copper removed during CMP experiments using blanket wafers under identical conditions.
  • Cu:PETEOS Sel Copper:PETEOS Selectivity—The ratio of the amount of copper removed to the amount of PETEOS (dielectric material) removed during CMP experiments using blanket wafers under identical conditions.

EXAMPLES

General

All percentages are weight percentages and all temperatures are degrees Centigrade unless otherwise indicated.

Chemical Mechanical Planarization (CMP) Methodology

In the examples presented below, CMP experiments were run using the procedures and experimental conditions given below.

Metrology

PETEOS thickness was measured with a Nanometrics, model, # 9200, manufactured by Nanometrics Inc, 1550 Buckeye, Milpitas, Calif. 95035-7418. The metal films were measured with a ResMap CDE, model 168, manufactured by Creative Design Engineering, Inc, 20565 Alves Dr, Cupertino, Calif., 95014. This tool is a four-point probe sheet resistance tool. Twenty-five and forty nine-point polar scans were taken with the respective tools at 3-mm edge exclusion. Planarity measurements were conducted on a P-15 Surface Profiler manufactured by KLA® Tencore, 160 Rio Robles, San Jose, Calif. 95161-9055.

CMP Tool

The CMP tool that was used is a Mirra®, manufactured by Applied Materials, 3050 Boweres Avenue, Santa Clara, Calif., 95054. A Politex® embossed pad, supplied by Rohm and Haas Electronic Materials, 3804 East Watkins Street, Phoenix, Ariz., 85034, was used on the platen for the blanket wafer polishing studies in Examples 1-8. An IC1010™ pad, supplied by Rohm and Haas Electronic Materials, 3804 East Watkins Street, Phoenix, Ariz., 85034, was used on the platen for the blanket wafer polishing studies in Examples 9-18.

In blanket wafers studies, groupings were made to simulate successive film removal: first copper, next tantalum or tantalum nitride, and finally the PETEOS. Polish time was 60 seconds per wafer. The Mirra® tool mid-point conditions for polishing blanket wafers in Examples 1-4 were: platen (or table) speed 123 rpm; head speed 112 rpm; inter-tube pressure 0.0 psi; membrane pressure 2.0 psi; slurry flow 200 ml/min. The Mirra® tool mid-point conditions for polishing blanket wafers in Examples 5-8 were: platen speed 90 rpm; head speed 84 rpm; inner tube vented; retaining ring pressure 2.4 psi; membrane pressure 2.0 psi; slurry flow 200 ml/min. The Mirra® tool mid-point conditions for polishing blanket wafers in Examples 9-14 were: platen speed 50 rpm; head speed 45 rpm; inner tube 4.5 psi; retaining ring pressure 6.0 psi; membrane pressure 4.5 psi; slurry flow 200 m/min. The Mirra® tool mid-point conditions for polishing blanket wafers in Examples 15-18 were: platen speed 119 rpm; head speed 113 rpm; inner tube 2.2 psi; retaining ring pressure 3.0 psi; membrane pressure 2.0 psi; slurry flow 200 ml/min.

Blanket Wafers

Blanket wafer polishing experiments were conducted using electrochemically deposited copper, tantalum, tantalum nitride, and PETEOS wafers. These blanket wafers were purchased from Silicon Valley Microelectronics, 1150 Campbell Ave, CA 95126. The blanket wafer film thickness specifications are summarized below:

    • PETEOS: 15,000 Å on silicon
    • Copper: 10,000 Å electroplated copper/1,000 Å copper seed/250 Å tantalum on silicon
    • Tantalum: 2000 Å/5,000 Å thermal oxide on silicon
    • Tantalum nitride: 3000 Å on 3,000 Å thermal oxide (on silicon)
      Polishing of Copper Pattern Wafers

The CMP431 copper pattern wafers were processed on the Mirra® tool configured with a IC1010™ pad described earlier. For Examples 15-18, the CMP431 copper pattern wafers were polished in two steps; first a bulk copper removal step, followed by final copper removal step to reach endpoint and achieve overpolish. The Mirra® tool mid-point conditions for the bulk copper removal step in Examples 15-18 were: platen speed 119 rpm; head speed 113 rpm; inner tube 4.5 psi; retaining ring pressure 6.0 psi; membrane pressure 4.5 psi; slurry flow 200 ml/min; polish time 78 seconds. The Mirra® tool mid-point conditions for the final copper removal step (to reach endpoint and achieve overpolish) in Examples 15-18 were: platen speed 119 rpm; head speed 113 rpm; inner tube 2.2 psi; retaining ring pressure 3.0 psi; membrane pressure 2.0 psi; slurry flow 200 ml/min. For the final copper removal step, the polish time to reach endpoint was controlled by the Mirra® CMP tool In Situ Rate Monitor (ISRM®) endpoint system, followed by a preset 20 second overpolish period.

Dishing Measurements Using Patterned Copper Wafers

Dishing is defined as the difference between the field dielectric material level (for example, PETEOS) or barrier material level (for example, tantalum and or tantalum nitride) of a wafer and the lowest point within the copper line of the wafer within a feature, after executing a CMP process on the wafer. In Examples 14-18 described below, the impact of the slurry formulation was determined by measuring dishing values for CMP431 copper pattern wafers polished on a Mirra® CMP tool using a P-15 Surface Profiler at the 100/100 features for the center-die location. Examples 14-18 used new, patterned copper wafers as received from the vendor; the results obtained in these examples are shown in Table 4.

Erosion Measurements Using Patterned Copper Wafers

Erosion is defined as the difference between the field dielectric material level (for example, PETEOS) or barrier material level (for example, tantalum and or tantalum nitride) of a wafer and the lowest point for the dielectric line of the wafer within a feature, after executing a CMP process on the wafer. In Examples 14-18 described below, the impact of the slurry formulation was determined by measuring erosion values for CMP431 copper pattern wafers polished on a Mirra® CMP tool using a P-15 Surface Profiler at the 9/1 features for the center-die location. Examples 14-18 used new, patterned copper wafers as received from the vendor; the results obtained in these examples are shown in Table 4.

Zeta Potential Measurements

Zeta potential measurements were made using a Colloidal Dynamics instrument, manufactured by Colloidal Dynamics Corporation, 11 Knight Street, Building E8, Warwick, RI 02886. This instrument measures the zeta potential (surface charge) of colloidal particles, such as surface-modified colloidal silica particles of boron surface-modified colloidal silica.

Preparation of Boron Surface-Modified Colloidal Silica

Boron surface-modified colloidal silica having an average particle diameter of 40 to 55 nanometers was prepared using the following procedure:

Approximately 1 kg of Amberlite® IR-120 ion exchange resin (Rohm and Haas Company, Philadelphia, Pa.) was washed with 1 liter of 20% sulfuric acid solution. The mixture was stirred and the resin was allowed to settle. The aqueous layer was decanted and washed with 10 liters of deionized water. The mixture was again allowed to settle and then the aqueous layer was decanted. This procedure was repeated until the decanted water was colorless. This procedure afforded acid-state resin.

Syton® HT-50 (12 kg, approximately 2.27 gallons, DuPont Air Products NanoMaterials LLC, Tempe, Ariz.) was placed in a 5 gallon mix tank equipped with an agitator. 2.502 kg of deionized water was added to the tank and the solution was allowed to mix a few minutes. The pH of the solution was measured to be approximately 10.2. With continued pH monitoring, small amounts of acid-state resin were added, while allowing the pH to stabilize in between additions. Additional resin was added in small portions until the pH had dropped to pH 1.90-2.20. Once this pH limit had been reached and was stable in this range, no further resin additions were made and the mixture was stirred for 1-1.5 hours. Subsequently the mixture was passed through a 500-mesh screen to remove the resin and afforded deionized Syton® HT-50.

A solution of 268 g of boric acid powder (Fisher Scientific, 2000 Park Lane, Pittsburgh, Pa., 15275) in 5.55 kg of deionized water was prepared in a 10 gallon mixing tank equipped with an agitator and a heater by slowly adding the boric acid powder until all had been added to the water and then agitating the mixture for 15 hours and increasing the temperature of the mixture to 55-65° C. Deionized, and diluted Syton® HT-50 (14.5 kg) was then added to the boric acid solution slowly over about 1.2 hours by adding it at approximately 200 ml/minute and maintaining the temperature greater than 52° C. while agitating the mixture. After this addition was completed, heating at 60° C. and agitation of the mixture was continued for 5.5 hours. The resulting solution was subsequently filtered through a 1-micron filter to afford boron surface-modified colloidal silica.

This boron surface-modified colloidal silica was characterized for colloid stability over 15 days using a Colloidal Dynamics instrument (11 Knight Street, Building E8, Warwick, RI 02886). This boron surface-modified colloidal silica was found to exhibit both constant pH (approximately 6.6) and zeta potential (approximately −58 mV) over the 15-day test period. The percentage of surface sites of this surface-modified colloidal silica occupied by boron-containing compound(s) was approximately 98%.

Examples 1-4

In Examples 1-4, CMP slurry compositions as shown in Table 1 were prepared and tested using the methodology, equipment, and processing as described supra. The CMP slurry compositions for Examples 1-4 were comprised of PVNO, boron surface-modified colloidal silica, ammonium fluoride, Surfynol® 104E, hydrogen peroxide, CDX2128, and ammonium hydroxide in an aqueous medium at pH 8. pH adjustment was done using ammonium hydroxide. The CMP slurry component amounts are shown in Table 1 for Examples 1-4. In each case, the balance of the composition was deionized water. The level of PVNO was varied as indicated below (and in Table 1):

    • Example 1—Table 1, PVNO level was 0.25 weight %
    • Example 2—Table 1, PVNO level was 0.125 weight %
    • Example 3—Table 1, PVNO level was 0.05 weight %
    • Example 4—Table 1, Comparative example, PVNO level was 0 weight %

The Example 1-4 compositions were used to polish copper, PETEOS, and tantalum blanket wafers; the results of the polishing experiments such as copper removal rate at 2.0 psi membrane pressure, PETEOS removal rate at 2.0 psi membrane pressure, tantalum removal rate at 2.0 psi membrane pressure, Ta:PETEOS Sel at 2.0 psi membrane pressure, Ta:Cu Sel at 2.0 psi membrane pressure, and Cu:PETEOS Sel at 2.0 psi membrane pressure are summarized in Table 1. As is illustrated in Table 1, the tantalum to PETEOS selectivity (Ta:PETEOS Sel) was observed to increase from 1.5 to 24.6 with increasing PVNO level over the range 0 to 0.25 weight % of PVNO. The tantalum to copper selectivity (Ta:Cu Sel) did not change appreciably with varying PVNO level over this range of 0 to 0.25 weight %.

Example 1-4 demonstrate that tantalum to PETEOS selectivity (Ta:PETEOS Sel) can be tuned to any selectivity value desired over a broad range depending upon the concentration of PVNO in the formulation.

Examples 5-8 Example 5 Procedure for Mixing the Slurry, 2.0 kg Batch Size

In a 4-liter beaker, 479 grams of de-ionized water were transferred. After adding water to the beaker, it was kept under agitation using a magnetic stirrer. Under agitation, 1000 grams of potassium stabilized silica was added slowly during a period of three minutes. The pH of the dispersion was 10.17. To the silica dispersion, 10 grams of CDX2128 (20 weight % solution), 3.0 grams of CDX2165 (20 weight % solution), and 4.0 grams of Zonyl® FSN (10 weight % solution) was added during a period of three minutes, the pH of the mixture was 10.03. To this dispersion, a mixture of 40 grams of citric acid (10 weight % solution) and 30.48 grams of potassium hydroxide (10 weight % solution) was added slowly during a period of 45 minutes. After the addition of the potassium citrate solution, the pH of the mixture was 8.2. The mixture was agitated for additional 10 minutes. To the formulated slurry, 333.3 grams of hydrogen peroxide (30 weight % solution) was added prior to polishing blanket copper, tantalum nitride, and PETEOS wafers using a Mirra® CMP tool.

In Examples 6-8, CMP slurry compositions as shown in Table 2 were prepared as described in Example 5, except PVNO was added to the mixture before the addition of hydrogen peroxide. The CMP slurry component amounts for Examples 5-8 are shown in Table 2. In each case, the balance of the composition was deionized water. The level of PVNO was varied as indicated below (and in Table 2):

    • Example 5—Table 2, Comparative example, PVNO level was 0 weight %
    • Example 6—Table 2, PVNO level was 0.5 weight %
    • Example 7—Table 2, PVNO level was 1.5 weight %
    • Example 8—Table 2, PVNO level was 2.0 weight %

The Example 5-8 compositions were used to polish copper, PETEOS, and tantalum nitride blanket wafers using the methodology, equipment, and processing as described supra. The results of the polishing experiments for Examples 5-8 such as copper removal rate at 2.0 psi membrane pressure, PETEOS removal rate at 2.0 psi membrane pressure, tantalum nitride removal rate at 2.0 psi membrane pressure, TaN:PETEOS Sel at 2.0 psi membrane pressure, TaN:Cu Sel at 2.0 psi membrane pressure, and Cu:PETEOS Sel at 2.0 psi membrane pressure are summarized in Table 2. As is illustrated in Table 2, clearly this data set indicates that as the concentration of PVNO increased from 0.5 weight % to 2.0 weight %, PETEOS removal rates dramatically decreased from 907 Å/min to essentially zero (within experimental error) in Example 8 whereas tantalum nitride removal rate essentially stayed the same. Therefore, the tantalum nitride to PETEOS selectivity (TaN:PETEOS Sel) increased as the concentration of PVNO increased from 0.5 weight % to 2.0 weight %. Similarly, the copper to PETEOS selectivity (Cu:PETEOS Sel) increased as the concentration of PVNO increased from 0.5 weight % to 2.0 weight %.

Examples 9-14

Examples 9-14 describe the effect on blanket wafer polishing of adding PVNO to CoppeReady® Cu300, a step 1 copper CMP slurry (DuPont Air Products NanoMaterials L.L.C., 2507 West Erie drive, Tempe, Ariz., 85282.) CoppeReady® Cu300 slurry contains 2.5 weight % of aluminate surface-modified silica (NAC532, DuPont Air Products NanoMaterials L.L.C., 2507 West Erie drive, Tempe, Ariz., 85282.)

    • Example 9: Procedure for Mixing CoppeReady® Cu300 with Hydrogen Peroxide, 1.0 kg Batch Size

In a 4-liter beaker, 956.7 grams of CoppeReady® Cu300 was transferred. After transferring the slurry to the beaker, it was kept under agitation using a magnetic stirrer. Under agitation, 43.3 grams of hydrogen peroxide (30 weight %) was added slowly during a period of three minutes. The pH of the dispersion was between 7.4 to 7.6. The formulated slurry was used to polish blanket copper, tantalum, and PETEOS wafers using a Mirra® CMP tool.

In Examples 10-14, CMP slurry compositions as shown in Table 3 were prepared as described in Example 9, except PVNO was added to the CoppeReady® Cu300 before the addition of hydrogen peroxide. The CMP slurry component amounts for Examples 9-14 are shown in Table 3. The level of PVNO was varied as indicated below (and in Table 3):

    • Example 9—Table 3, Comparative example, PVNO level was 0 weight %
    • Example 10—Table 3, PVNO level was 0.05 weight %
    • Example 11—Table 3, PVNO level was 0.10 weight %
    • Example 12—Table 3, PVNO level was 0.15 weight %
    • Example 13—Table 3, PVNO level was 0.25 weight %
    • Example 14—Table 3, PVNO level was 0.50 weight %

The Example 9-14 compositions were used to polish copper, PETEOS, and tantalum blanket wafers using the methodology, equipment, and processing as described supra. The results of the polishing experiments for Examples 9-14 such as copper removal rate at 4.5 psi membrane pressure, PETEOS removal rate at 4.5 psi membrane pressure, tantalum removal rate at 4.5 psi membrane pressure, Ta:PETEOS Sel at 4.5 psi membrane pressure, Ta:Cu Sel at 4.5 psi membrane pressure, and Cu:PETEOS Sel at 4.5 psi membrane pressure are summarized in Table 3. As is illustrated in Table 3, clearly as the concentration of PVNO increased from 0.05 weight % to 0.5 weight %, the PETEOS removal rate dramatically decreased from 96 Å/min to essentially zero (within experimental error) in Examples 12, 13, and 14. Thus, at or above a 0.15 weight % PVNO concentration in CoppeReady® Cu300 the PETEOS removal rate is zero within experimental error. Therefore, the tantalum to PETEOS selectivity (Ta:PETEOS Sel) and the copper to PETEOS selectivity (Cu:PETEOS Sel) both increased as the concentration of PVNO increased from 0.05 weight % to 0.5 weight %. Interestingly, the copper removal rate was found to increase slightly from 2113 Å/min to 2024 Å/min with increasing PVNO concentration, while the tantalum removal rate was found to decrease from 476 Å/min to 259 Å/min with increasing PVNO concentration.

Examples 15-18

Examples 15-18 describe the effect on blanket and CMP431 pattern wafer polishing of adding PVNO to CoppeReady® Cu300, a step 1 copper CMP slurry from DuPont Air Products NanoMaterials L.L.C., 2507 West Erie drive, Tempe, Ariz., 85282.

In Examples 15-18, CMP slurry compositions as shown in Table 4 were prepared as described in Example 9, except for Examples 16-18 PVNO was added to the CoppeReady® Cu300 before the addition of hydrogen peroxide. The formulated slurries were used to polish blanket copper, blanket tantalum, blanket PETEOS, and CMP431 pattern wafers using a Mirra® CMP tool. The CMP slurry component amounts for Examples 15-18 are shown in Table 3. The level of PVNO was varied as indicated below (and in Table 4):

    • Example 15—Table 3, Comparative example, PVNO level was 0 weight %
    • Example 16—Table 3, PVNO level was 0.15 weight %
    • Example 17—Table 3, PVNO level was 0.25 weight %
    • Example 18—Table 3, PVNO level was 0.50 weight %

The Example 15-18 compositions were used to polish copper, PETEOS, and tantalum blanket wafers, and CMP431 pattern wafers; the results of the polishing experiments such as copper removal rate at 2.0 psi membrane pressure, PETEOS removal rate at 2.0 psi membrane pressure, tantalum removal rate at 2.0 psi membrane pressure, Ta:PETEOS Sel at 2.0 psi membrane pressure, Ta:Cu Sel at 2.0 psi membrane pressure, Cu:PETEOS Sel at 2.0 psi membrane pressure, dishing at 100/100 features, dishing at 9/1 features, and erosion at 9/1 features, are summarized in Table 4. As is illustrated in Table 4, clearly the results indicate that, as the concentration of PVNO increased from 0 weight % to 0.5 weight % in Examples 15-18, the blanket wafer PETEOS removal rate dramatically decreased from 116 Å/min to essentially zero (within experimental error) in Examples 16, 17, and 18. As the concentration of PVNO increased from 0 weight % to 0.5 weight % in Examples 15-18, the pattern wafer erosion at the 9/1 feature decreased dramatically from 500 Å to 250 Å. Interestingly, the blanket wafer copper removal rate decreased slightly from 2103 Å to 1818 Å, whereas the blanket wafer tantalum removal rate decreased from 442 Å/min to 157 Å/min. In addition to reducing the blanket wafer PETEOS removal rate to essentially zero and reducing pattern wafer erosion at 9/1 features, the polishing data for Examples 14-18 also indicates a reduction in dishing of 700 Å to 550 Å at the pattern wafer 9/1 feature, and a reduction in dishing of 594 Å to 535 Å at the pattern wafer 100/100 feature.

Influence of Abrasive Concentration on the Effective PVNO Concentration Requirement in Step 1 and Step 2 Copper CMP Processes

The formulations for Examples 1-4 (Table 1) and Examples 5-8 (Table 2) are for step 2 copper CMP or barrier CMP. The abrasive concentration for formulations in Examples 1-4 was held at 5.0 weight %, whereas the abrasive concentration for formulations in Examples 5-8 was held at 15.0 weight %. The formulations for Examples 9-18 (Tables 3 and 4) are for step 1 copper CMP, where the abrasive concentration was held at 2.5 weight %. As the data indicates in Tables 1-4, the PVNO was effective to tune the PETEOS removal rate for both step 1 and step 2 copper CMP processes and the removal rate selectivity for PETEOS relative to barrier materials and/or copper. The addition of sufficient PVNO in the slurry formulation affords suppression of the PETEOS removal rate to essentially zero for both step 1 and step 2 copper CMP processes. Interestingly, this data set also indicates that, as the concentration of abrasive increased from 2.5% abrasive (Examples 9-18) to 15.0 wt % (Examples 5-8), the concentration of PVNO required to suppress PETEOS removal rate increased. More specifically, for the polishing formulation in Example 12 with 2.5 weight % abrasive, 0.15 weight % PVNO was needed to suppress PETEOS to essentially zero, whereas the slurry with 15 weight % abrasive in Example 8 required 2.0 weight % PVNO to suppress PETEOS to essentially zero. This observed increased requirement in PVNO concentration for suppression of the dielectric (e.g., PETEOS) removal rate in slurries with higher abrasive concentrations is believed to be due to the adsorption of PVNO to the abrasive surface. Hence a slurry having a higher level of abrasive requires a higher amount of PVNO in the formulation for suppression of the dielectric removal rate, when compared to a slurry having a lower level of abrasive. The ratio of the weight % PVNO in the slurry to the weight % silica (or surface-modified silica) in the slurry (PVNO:Silica Ratio) is summarized in Table 5 for Examples 1-18. Table 5 also includes the calculated percent reduction of PETEOS blanket wafer removal rates in relation to the relevant comparative example. The percent reduction of PETEOS blanket wafer removal rate (PETEOS RR) in relation to the relevant comparative example is defined as: 100 × ( PETEOS ⁢   ⁢ RR ⁢   ⁢ for ⁢   ⁢ the ⁢   ⁢ Example - ⁢   PETEOS ⁢   ⁢ RR ⁢   ⁢ of ⁢   ⁢ relevant ⁢   ⁢ Comparative ⁢   ⁢ Example ) PETEOS ⁢   ⁢ RR ⁢   ⁢ of ⁢   ⁢ relevant ⁢   ⁢ Comparative ⁢   ⁢ Example

The drawing presents the data from Table 5, and shows the effect of polyvinylpyridine-N-oxide:Silica ratio (PVNO:Silica Ratio) on the percent reduction of PETEOS blanket wafer removal rates in relation to the relevant comparative example. As shown in the drawing and Table 5, a PVNO:Silica ratio (or PVNO:Abrasive ratio) of at least 0.025, more preferably of at least 0.050, and most preferably of at least 0.100 affords suppression of the PETEOS removal rate to essentially zero for both step 1 and step 2 copper CMP processes.

TABLE 1 Effect of polyvinylpyridine-N-oxide on Cu, PETEOS, and Tantalum Blanket Wafer Removal Rates and Removal Rate Selectivities Example 1: Example 2: Example 3: Example 4: PVNO 0.25 PVNO 0.125 PVNO 0.05 Comparative weight % weight % weight % No PVNO Boron surface-modified 5 5 5 5 colloidal silica (weight % silica) Ammonium fluoride (weight %) 0.22 0.22 0.22 0.22 S104E (weight %) 0.07 0.07 0.07 0.07 CDX2128 (weight %) 0.1 0.1 0.1 0.1 PVNO (weight %) 0.25 0.125 0.05 0 Hydrogen peroxide (weight %) 1.3 1.3 1.3 1.3 Deionized Water (weight %) Balance Balance Balance Balance pH (adjusted with ammonium 8 8 8 8 hydroxide) Copper removal rate at 2.0 psi 127 112 117 115 (Å/min) PETEOS removal rate at 2.0 psi 20 130 279 341 (Å/min) Tantalum removal rate at 2.0 psi 493 495 526 516 (Å/min) Ta:PETEOS Sel at 2.0 psi 24.6 3.8 1.9 1.5 Ta:Cu Sel at 2.0 psi 3.9 4.4 4.5 4.5 Cu:PETEOS Sel at 2.0 psi 6.4 0.86 0.42 0.34 PVNO:Silica ratio 0.050 0.025 0.010 0

TABLE 2 Effect of polyvinylpyridine-N-oxide on Cu, PETEOS, and Tantalum Nitride Blanket Wafer Removal Rates and Removal Rate Selectivities Example 5 Example 6: Example 7: Example 8: Comparative: PVNO 0.5 PVNO 1.5 PVNO 2.0 no PVNO weight % weight % weight % Potassium stabilized silica 15 15 15 15 (weight % solids) Citric acid (weight. %) 0.2 0.2 0.2 0.2 CDX2165 (weight %) 0.03 0.03 0.03 0.03 CDX2128 (weight %) 0.1 0.1 0.1 0.1 Zonyl FSN (weight %) 0.02 0.02 0.02 0.02 PVNO (weight %) 0.0 0.5 1.5 2.0 Hydrogen peroxide (weight %) 5.0 5.0 5.0 5.0 Water Balance Balance balance balance Potassium hydroxide (weight 0.078 0.078 0.078 0.078 %) pH 8.5 8.5 8.5 8.5 Cu removal rate at 2.0 psi 766 752 738 660 (Å/min) Tantalum nitride removal rate 576 574 572 587 at 2.0 psi (Å/min) PETEOS removal rate at 2.0 psi 907 365 34 Essentially (Å/min) zero* TaN:PETEOS Sel at 2.0 psi 0.6 1.5 16 TaN:Cu Sel at 2.0 psi 0.8 0.8 0.8 0.9 Cu:PETEOS Sel at 2.0 psi 0.8 2.0 21 PVNO:Silica ratio 0 0.033 0.100 0.133
*PETEOS removal rates below 20 Å/min is stated as essentially zero (within experimental error, measurement accuracy.)

TABLE 3 Effect of polyvinylpyridine-N-oxide on Cu, PETEOS, and Tantalum Blanket Wafer Removal Rates and Removal Rate Selectivities Example 9 Example 10: Example 11: Example 12: Example 13: Example 14: Comparative: CoppeReady ® CoppeReady ® CoppeReady ® CoppeReady ® CoppeReady ® CoppeReady ® Cu300 plus Cu300 plus Cu300 plus Cu300 plus Cu300 plus Cu300 PVNO 0.05 PVNO 0.10 PVNO 0.15 PVNO 0.25 PVNO 0.50 No PVNO weight % weight % weight % weight % weight % PVNO (weight %) 0 0.05 0.10 0.15 0.25 0.50 Aluminate surface- 2.5 2.5 2.5 2.5 2.5 2.5 modified silica; a component of CoppeReady ® Cu300 (weight % solids) pH 7.5 7.5 7.5 7.5 7.5 7.5 Hydrogen peroxide (weight 1.3 1.3 1.3 1.3 1.3 1.3 %) Copper removal rate at 4.5 psi 2113 2303 2343 2648 1717 2024 (Å/min) Tantalum removal rate at 476 477 409 405 334 259 4.5 psi (Å/min) PETEOS removal rate at 96 58 27 Essentially zero* Essentially zero* Essentially zero* 4.5 psi (Å/min) Cu:PETEOS Sel at 4.5 psi 22 40 87 Ta:PETEOS Sel at 4.5 psi 5 8 15 PVNO:Silica ratio 0 0.020 0.040 0.060 0.100 0.200
*PETEOS removal rates below 20 Å/min is stated as essentially zero (within experimental error, measurement accuracy.)

TABLE 4 Effect of polyvinylpyridine-N-oxide on Cu, PETEOS, and Tantalum Blanket Wafer Removal Rates, Removal Rate Selectivities, and Pattern Wafer Dishing and Erosion Example 16: Example 17: Example 18: Example 15 CoppeReady ® CoppeReady CoppeReady Comparative: Cu300 plus  ® Cu300 plus  ® Cu300 plus CoppeReady ® Cu300 PVNO 0.15 PVNO 0.25 PVNO 0.50 No PVNO weight % weight % weight % PVNO (weight %) 0 0.15 0.25 0.50 Aluminate surface-modified silica; a component 2.5 2.5 2.5 2.5 of CoppeReady ® Cu300 (weight % solids) pH 7.5 7.5 7.5 7.5 Hydrogen peroxide (weight %) 1.3 1.3 1.3 1.3 Copper removal rate at 2.0 psi (Å/min) 2103 1898 2058 1818 Tantalum removal rate at 2.0 psi (Å/min) 442 213 215 157 PETEOS removal rate at 2.0 psi (Å/min) 116 Essentially Essentially Essentially zero* zero* zero* Cu:PETEOS Sel at 2.0 psi 18 Ta:PETEOS Sel at 2.0 psi 3.8 Dishing at 100/100 features; center-die (Å) 594 595 554 535 Dishing at 9/1 features; center-die (Å) 700 600 550 550 Erosion at 9/1 features; center-die (Å) 500 400 275 275 PVNO:Silica ratio 0 0.060 0.100 0.200
*PETEOS removal rates below 20 Å/min is stated as essentially zero (within experimental error, measurement accuracy.)

TABLE 5 Effect of polyvinylpyridine-N-oxide:Silica (PVNO:Silica) Ratio on the Percent Reduction of PETEOS Blanket Wafer Removal Rates in Relation to the Relevant Comparative Example Percent Reduction of PETEOS Removal Rate in Relation to PETEOS the Relevant Comparative PVNO/Silica removal rate Comparative Example Ratio (Å/min) Example Example 1 Example 4 0.050 20 94% Example 2 Example 4 0.025 130 62% Example 3 Example 4 0.010 279 18% Comparative Example 4 0 341 0% Example 4 Comparative Example 5 0 907 0% Example 5 Example 6 Example 5 0.033 365 60% Example 7 Example 5 0.100 34 96% Example 8 Example 5 0.133 0 100% Comparative Example 9 0 96 0% Example 9 Example 10 Example 9 0.020 58 40% Example 11 Example 9 0.040 27 72% Example 12 Example 9 0.060 0 100% Example 13 Example 9 0.100 0 100% Example 14 Example 9 0.200 0 100% Comparative Example 15 0 116 0% Example 15 Example 16 Example 15 0.060 0 100% Example 17 Example 15 0.100 0 100% Example 18 Example 15 0.200 0 100%

The present invention has been set forth with regard to several preferred embodiments, however the present invention's full scope should not be limited to the disclosure of those embodiments, but rather the full scope of the present invention should be ascertained from the claims which follow.

Claims

1. A step 2 copper chemical-mechanical planarization composition comprising:

a) an abrasive;
b) a dielectric protector comprising a polyvinylpyridine-N-oxide polymer;
c) an oxidizing agent; and
d) water.

2. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the abrasive is a colloidal abrasive.

3. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the abrasive is silica or surface-modified silica.

4. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the abrasive is boron surface-modified silica or aluminate surface-modifed silica.

5. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level in the composition ranging from 0.05 weight % to 3 weight %.

6. The step 2 copper chemical-mechanical planarization composition of claim 5 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level in the composition ranging from 0.05 weight % to 3 weight % and the Polyvinylpyridine-N-oxide polymer:Abrasive ratio is greater than 0.05.

7. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the polyvinylpyridine-N-oxide polymer is present in an amount sufficient to protect the dielectric.

8. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the polyvinylpyridine-N-oxide polymer is a homopolymer of polyvinylpyridine-N-oxide.

9. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the polyvinylpyridine-N-oxide polymer has a number average molecular weight ranging from 25,000 Daltons to 250,000 Daltons.

10. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the oxidizing agent is hydrogen peroxide.

11. The step 2 copper chemical-mechanical planarization composition of claim 10 wherein hydrogen peroxide is present at a level ranging from 0.05 weight % to 6 weight % of the total weight of the composition.

12. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the composition has a pH ranging from 6 to 10.

13. The step 2 copper chemical-mechanical planarization composition of claim 1 further comprising d) a surfactant.

14. The step 2 copper chemical-mechanical planarization composition of claim 13 wherein the surfactant is a nonionic surfactant.

15. The step 2 copper chemical-mechanical planarization composition of claim 1 further comprising e) a corrosion inhibitor.

16. The step 2 copper chemical-mechanical planarization composition of claim 1 wherein the polyvinylpyridine-N-oxide polymer is solubilized and/or dispersed in water.

17. A method of step 2 copper chemical-mechanical planarization comprising the steps of:

A) placing a substrate comprising copper, at least one dielectric material and at least one barrier material in contact with a polishing pad;
B) delivering a chemical-mechanical planarization composition comprising a) an abrasive; b) a dielectric protector comprising a polyvinylpyridine-N-oxide polymer; c) an oxidizing agent; and d) water; and
C) planarizing the substrate with the step 2 copper chemical-mechanical planarization composition.

18. The method of claim 17 wherein the abrasive in the composition employed in the method is a colloidal abrasive.

19. The method of claim 18 wherein the abrasive is silica or surface-modified silica.

20. The method of claim 18 wherein the abrasive is boron surface-modified silica or aluminate surface-modifed silica.

21. The method of claim 17 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level ranging from 0.05 weight % to 3 weight % in the composition employed in the method.

22. The method of claim 21 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level ranging from 0.05 weight % to 3 weight % in the composition employed in the method and the Polyvinylpyridine-N-oxide polymer:Abrasive ratio is greater than 0.05.

23. The method of claim 17 wherein the polyvinylpyridine-N-oxide polymer in the composition employed in the method is present in an amount sufficient to protect the dielectric.

24. The method of claim 17 wherein the polyvinylpyridine-N-oxide polymer is a homopolymer of polyvinylpyridine-N-oxide.

25. The method of claim 17 wherein the polyvinylpyridine-N-oxide polymer in the composition employed in the method has a number average molecular weight ranging from 25,000 Daltons to 250,000 Daltons.

26. The method of claim 17 wherein the oxidizing agent in the composition employed in the method is hydrogen peroxide.

27. The method of claim 17 wherein hydrogen peroxide is present at a weight percent level ranging from 0.05 weight % to 6 weight % of the total weight of the composition employed in the method.

28. The method of claim 17 wherein the composition employed in the method has a pH ranging from 6 to 10.

29. The method of claim 17 wherein the composition employed in the method further comprises d) a surfactant.

30. The method of claim 29 wherein the surfactant is a nonionic surfactant.

31. The method of claim 17 wherein the composition employed in the method further comprises d) a corrosion inhibitor.

32. The method of claim 17 wherein the polyvinylpyridine-N-oxide polymer in the composition employed in the method is solubilized and/or dispersed in water.

33. A step 1 copper chemical-mechanical planarization composition comprising:

a) an abrasive;
b) a dielectric protector comprising apolyvinylpyridine-N-oxide polymer;
c) an oxidizing agent; and
d) water.

34. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the abrasive is a colloidal abrasive.

35. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the abrasive is silica or surface-modified silica.

36. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the abrasive is boron surface-modified silica or aluminate surface-modifed silica.

37. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level in the composition ranging from 0.01 weight % to 0.75 weight %.

38. The step 1 copper chemical-mechanical planarization composition of claim 37 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level in the composition ranging from 0.01 weight % to 0.75 weight % and the Polyvinylpyridine-N-oxide polymer:Abrasive ratio is greater than 0.05.

39. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the polyvinylpyridine-N-oxide polymer is present in an amount sufficient to protect the dielectric.

40. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the polyvinylpyridine-N-oxide polymer is a homopolymer of polyvinylpyridine-N-oxide.

41. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the polyvinylpyridine-N-oxide polymer has a number average molecular weight ranging from 25,000 Daltons to 250,000 Daltons.

42. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the oxidizing agent is hydrogen peroxide.

43. The step 1 copper chemical-mechanical planarization composition of claim 42 wherein hydrogen peroxide is present at a weight percent level ranging from 0.05 weight % to 6 weight % of the total weight of the composition.

44. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the composition has a pH ranging from 7 to 9.

45. The step 1 copper chemical-mechanical planarization composition of claim 33 further comprising e) a surfactant.

46. The step 1 copper chemical-mechanical planarization composition of claim 45 wherein the surfactant is a nonionic surfactant.

47. The step 1 copper chemical-mechanical planarization composition of claim 33 further comprising e) a corrosion inhibitor.

48. The step 1 copper chemical-mechanical planarization composition of claim 33 wherein the polyvinylpyridine-N-oxide polymer is solubilized and/or dispersed in water.

49. A method of step 1 copper chemical-mechanical planarization comprising the steps of:

A) placing a substrate comprising copper, at least one dielectric material and at least one barrier material in contact with a polishing pad;
B) delivering a chemical-mechanical planarization composition comprising a) an abrasive; b) a dielectric protector comprising a polyvinylpyridine-N-oxide polymer; c) an oxidizing agent; and d) water; and
C) planarizing the substrate with the step 1 copper chemical-mechanical planarization composition.

50. The method of claim 49 wherein the abrasive in the composition employed in the method is a colloidal abrasive.

51. The method of claim 49 wherein the abrasive is silica or surface-modified silica.

52. The method of claim 49 wherein the abrasive is boron surface-modified silica or aluminate surface-modifed silica.

53. The method of claim 49 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level in the composition employed in the method ranging from 0.01 weight % to 0.75 weight %.

54. The method of claim 53 wherein the polyvinylpyridine-N-oxide polymer is present at a weight percent level in the composition employed in the method ranging from 0.01 weight % to 0.75 weight % and the Polyvinylpyridine-N-oxide polymer:Abrasive ratio is greater than 0.05.

55. The method of claim 49 wherein the polyvinylpyridine-N-oxide polymer in the composition employed in the method is present in an amount sufficient to protect the dielectric.

56. The method of claim 49 wherein the polyvinylpyridine-N-oxide polymer is a homopolymer of polyvinylpyridine-N-oxide.

57. The method of claim 49 wherein the polyvinylpyridine-N-oxide polymer in the composition employed in the method has a number average molecular weight ranging from 25,000 Daltons to 250,000 Daltons.

58. The method of claim 49 wherein the oxidizing agent in the composition employed in the method is hydrogen peroxide.

59. The method of claim 49 wherein hydrogen peroxide is present at a weight percent level in the composition employed in the method ranging from 0.05 weight % to 6 weight % of the total weight of the composition.

60. The method of claim 49 wherein the composition has a pH ranging from 7 to 9.

61. The method of claim 49 wherein the composition employed in the method further comprises D) a surfactant.

62. The method of claim 61 wherein the surfactant is a nonionic surfactant.

63. The method of claim 49 wherein the composition employed in the method further comprises D) a corrosion inhibitor.

64. The method of claim 49 wherein the polyvinylpyridine-N-oxide polymer in the composition employed in the method is solubilized and/or dispersed in water.

Patent History
Publication number: 20050215183
Type: Application
Filed: Apr 8, 2005
Publication Date: Sep 29, 2005
Inventors: Junaid Siddiqui (Richmond, VA), Bin Hu (Chandler, AZ)
Application Number: 11/101,815
Classifications
Current U.S. Class: 451/41.000