Additives for improving particle dispersion in CMP slurries

Abstract

The present invention provides a chemical mechanical polishing composition comprising: (a) about 0.05 wt % to about 10 wt % of an abrasive; and (b) a dispersant, the dispersant being a linear or branched C2-C 10 The present invention provides a chemical-mechanical polishing composition comprising: (a) a dispersant that is an alkylene diol; and (c) water; and (b) a pH of about 2 to about 6. The present invention also provides a method for chemically mechanically polishing a substrate by contacting the substrate with the chemical-mechanical polishing composition of the present invention.

Description

[Background technology]

[0001] Compositions and methods for planarizing or polishing the surface of a substrate are well known in the art. Polishing compositions (also known as polishing slurries) generally contain an abrasive material in a liquid carrier and are applied to a surface by contacting the surface with a polishing pad saturated with the polishing composition. Common abrasive materials include silicon dioxide, cerium oxide, aluminum oxide, zirconium oxide, and tin oxide. Polishing compositions are generally used in combination with a polishing pad (e.g., a polishing cloth or disk). Instead of or in addition to being suspended in the polishing composition, the abrasive material may be incorporated into the polishing pad.

[0002] In many cases, it is desirable for the abrasive material to have a narrow particle size distribution.When the abrasive is suspended in the polishing composition, the abrasive may aggregate or agglomerate on standing, thereby forming particles with a particle size significantly larger than the average particle size of the abrasive material.It is believed that an increase in the proportion of abrasive particles with a large particle size leads to an increase in micro-scratches on the surface of the substrate polished with the polishing composition containing the abrasive.Micro-scratches can lead to substrate defects that do not meet stringent quality requirements.

[0003] Thus, there remains a need in the art for polishing compositions that have improved abrasive particle size stability. Summary of the Invention

[0004] The present invention relates to a chemical mechanical polishing composition comprising: (a) about 0.05% to about 10% by weight of an abrasive; and (b) a dispersant, the dispersant being a linear or branched C2-C 10 A chemical-mechanical polishing composition is provided that includes a dispersant, which is an alkylene diol; and (c) water. The chemical-mechanical polishing composition has a pH of about 2 to about 6.

[0005] The present invention also provides a method for chemically mechanically polishing a substrate, the method comprising: (i) providing a substrate; (ii) providing a polishing pad; and (iii) a chemical mechanical polishing composition comprising: (a) about 0.05% to about 10% by weight of an abrasive; and (b) a dispersant, the dispersant being a linear or branched C2-C 10 Also provided is a method including: providing a chemical-mechanical polishing composition having a pH of about 2 to about 6, the chemical-mechanical polishing composition including (a) a dispersing agent, the dispersing agent being an alkylene diol; and (c) water; (iv) contacting a substrate with the polishing pad and the chemical-mechanical polishing composition; and (v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to grind at least a portion of a surface of the substrate to polish the substrate. [Brief description of the drawings]

[0006] [Figure 1] 1 is a graph showing the average particle size of a polishing composition containing colloidal silica at 0, 1, 2, or 3 weeks of storage at 45° C., at pH values ​​of 3, 4, or 5, and at 0, 2, or 10% by weight of 1,4-butanediol. [Diagram 2] 1 is a graph showing the average particle size of a polishing composition containing alumina surface-treated with a sulfonic acid-containing polymer at 0, 1, 2, 3, 4, and 5 weeks of storage at 45° C., at pH values ​​of 2 or 4, and with 0 wt%, 0.5 wt%, 2 wt%, or 10 wt% 1,4-butanediol. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] The present invention relates to a chemical mechanical polishing composition comprising: (a) about 0.05% to about 10% by weight of an abrasive; and (b) a dispersant, the dispersant being a linear or branched C2-C 10 A chemical-mechanical polishing composition is provided that comprises, consists essentially of, or consists of a dispersing agent that is an alkylene diol; and (c) water, the chemical-mechanical polishing composition having a pH of about 2 to about 6.

[0008] The abrasive may be any suitable abrasive. The abrasive particles may comprise, consist essentially of, or consist of any suitable particulate material, which materials are typically metal oxides and / or metalloid oxides (collectively hereinafter referred to as "metal oxides"). Examples of suitable materials include alumina, treated alumina (e.g., surface-treated alumina), colloidal silica, fumed silica, surface-modified silica, and combinations thereof.

[0009] The alumina can be any suitable alumina, for example, alpha-alumina, gamma-alumina, or fumed alumina. The alumina can be a treated alumina, where the alumina particles can be surface treated with an anionic polymer, such as a copolymer containing sulfonic acid monomer units, such as polysulfonic acid, polystyrene sulfonic acid, poly(2-acrylamido-2-methyl-1-propanesulfonic acid), and the like.

[0010] The silica can be unmodified silica or surface-modified silica, many of which are known in the art. For example, the surface-modified silica can be surface-modified by doping with aluminum ions, by treating with a surface-modifying agent such as silanes, including amino-containing silanes, alkyl silanes, etc. In a preferred embodiment, the silica can be colloidal silica (e.g., unmodified colloidal silica).

[0011] When the silica is a colloidal silica, the colloidal silica can be any suitable colloidal silica. For example, the colloidal silica can be a wet process silica, such as condensation polymerized silica. Condensation polymerized silica is typically prepared by condensing Si(OH)4 to form colloidal particles, where colloidal is defined as having an average particle size of about 1 nm to about 1000 nm. Such abrasive particles can be prepared according to U.S. Pat. No. 5,230,833, or can be obtained as any of a variety of commercially available products, such as Akzo-Nobel Bindzil™ 50 / 80, 30 / 360, 159 / 500, 40 / 220, and 40 / 130 products, CJ2-2 products, Nalco 1050, 1060, 2327, and 2329 products, and other similar products available from DuPont, Bayer, Applied Research, Nissan Chemical, Fuso, and Clariant.

[0012] The polishing composition can include any suitable amount of abrasive. Typically, the polishing composition includes about 1 wt% or more of abrasive, for example, about 1.5 wt% or more, about 2 wt% or more, or about 2.5 wt% or more. Alternatively, or in addition, the polishing composition includes about 5 wt% or less of abrasive, for example, about 4.5 wt% or less, about 4 wt% or less, or about 3.5 wt% or less. Thus, the polishing composition can include an amount of abrasive bounded by any two of the aforementioned endpoints. For example, the polishing composition may contain about 1 wt % to about 5 wt %, e.g., about 1 wt % to about 4.5 wt %, about 1 wt % to about 4 wt %, about 1 wt % to about 3.5 wt %, about 1.5 wt % to about 5 wt %, about 1.5 wt % to about 4.5 wt %, about 1.5 wt % to about 4 wt %, about 1.5 wt % to about 3.5 wt %, about 2 wt % to about 5 wt %, about 2 wt % to about 4.5 wt %, about 2 wt % to about 4 wt %, about 2 wt % to about 3.5 wt %, about 2.5 wt % to about 5 wt %, about 2.5 wt % to about 4.5 wt %, about 2.5 wt % to about 4 wt %, or about 2.5 wt % to about 3.5 wt % of the abrasive.

[0013] The abrasive is preferably colloidally stable. The term colloid refers to the suspension of the abrasive particles in the liquid carrier. Colloidal stability refers to the maintenance of that suspension over time. In the context of the present invention, an abrasive is considered colloidally stable if, when the abrasive is placed in a 100 ml graduated cylinder and allowed to sit unstirred for 2 hours, the difference between the concentration of the particles in the bottom 50 ml of the graduated cylinder ([B], in g / ml) and the concentration of the particles in the top 50 ml of the graduated cylinder ([T], in g / ml) divided by the initial concentration of the particles in the abrasive composition ([C], in g / ml) is 0.5 or less (i.e. {[B]-[T]} / [C]≦0.5). More preferably, the value of [B]-[T] / [C] is 0.3 or less, and most preferably 0.1 or less.

[0014] The abrasive may have any suitable average particle size (e.g., average particle diameter). The particle size of the abrasive particles is the diameter of the smallest sphere that contains the abrasive particles. The abrasive may have an average particle size of about 5 nm or more, for example, about 10 nm or more, about 15 nm or more, about 20 nm or more, about 25 nm or more, about 30 nm or more, about 35 nm or more, about 40 nm or more, about 45 nm or more, about 50 nm or more, about 55 nm or more, about 60 nm or more, about 65 nm or more, about 70 nm or more, about 75 nm or more, about 80 nm or more, about 85 nm or more, about 90 nm or more, about 95 nm or more, or about 100 nm or more. Alternatively, or in addition, the abrasive can have an average particle size of about 200 nm or less, e.g., about 190 nm or less, about 180 nm or less, about 170 nm or less, about 160 nm or less, about 150 nm or less, about 140 nm or less, about 130 nm or less, about 120 nm or less, about 110 nm or less, about 100 nm or less, about 95 nm or less, about 90 nm or less, about 85 nm or less, about 80 nm or less, about 75 nm or less, or about 70 nm or less. Thus, the abrasive can have an average particle size bounded by any two of the foregoing endpoints. For example, the abrasive may have an average particle size of about 10 nm to about 200 nm, e.g., about 10 nm to about 190 nm, about 10 nm to about 180 nm, about 15 nm to about 170 nm, about 20 nm to about 160 nm, about 20 nm to about 150 nm, about 20 nm to about 140 nm, about 20 nm to about 130 nm, about 20 nm to about 120 nm, about 20 nm to about 110 nm, about 100 nm to about 200 nm, about 100 nm to about 190 nm, about 100 nm to about 180 nm, about 100 nm to about 170 nm, about 100 nm to about 160 nm, about 100 nm to about 150 nm, about 10 nm to about 100 nm, about 25 nm to about 80 nm, or about 30 nm to about 70 nm.

[0015] The polishing composition contains a dispersant, and the dispersant is a linear or branched C2-C 10 In certain preferred embodiments, the dispersant is a linear or branched C2 to C7 alkylene diol. In certain preferred embodiments, the dispersant is a linear or branched C4 to C7 alkylene diol. In certain preferred embodiments, the dispersant is a linear or branched C4 to C7 alkylene diol. 10 Alkylene diols are linear C2-C 10An alkylene diol (e.g., a linear C2-C7 alkylene diol or a linear C4-C7 alkylene diol). As will be appreciated by those skilled in the art, an alkylene diol comprises an aliphatic carbon chain with two hydroxyl groups attached thereto, the hydroxyl groups typically being attached to different carbon atoms of the alkylene diol. As will be further appreciated by those skilled in the art, a C2 alkylene diol cannot be branched since there are only two carbon atoms in a C2 alkylene diol, whereas a C3-C 10 The alkylene diol may be linear or branched, with the branch containing one or more carbon atoms attached to the backbone of the alkylene diol. The alkylene diol may contain 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. In one embodiment, the dispersant is selected from 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and combinations thereof. In a preferred embodiment, the dispersant is 1,4-butanediol.

[0016] The polishing composition may contain any suitable amount of dispersant.For example, the polishing composition may contain about 0.5 wt% or more, for example, about 0.6 wt% or more, about 0.7 wt% or more, about 0.8 wt% or more, about 0.9 wt% or more, about 1 wt% or more, about 1.1 wt% or more, about 1.2 wt% or more, about 1.3 wt% or more, about 1.4 wt% or more, about 1.5 wt% or more, about 1.6 wt% or more, about 1.7 wt% or more, about 1.8 wt% or more, about 1.9 wt% or more, about 2 wt% or more, about 2.1 wt% or more, about 2.2 wt% or more, about 2.3 wt% or more, about 2.4 wt% or more, about 2.5 wt% or more, about 2.6 wt% or more, about 2.7 wt% or more, about 2.8 wt%, about 2.9 wt% or more, or about 3 wt% or more of dispersant. Alternatively, or in addition, the polishing composition can contain about 20 wt% or less of dispersant, e.g., about 19.5 wt% or less, about 19 wt% or less, about 18.5 wt% or less, about 18 wt% or less, about 17.5 wt% or less, about 17 wt% or less, about 16.5 wt% or less, about 16 wt% or less, about 15.5 wt% or less, about 15 wt% or less, about 14.5 wt% or less, about 14 wt% or less, about 13.5 wt% or less, about 13 wt% or less, about 12.5 wt% or less, about 12 wt% or less, about 11.5 wt% or less, about 11 wt% or less, about 10.5 wt% or less, or about 10 wt% or less of dispersant. Thus, the polishing composition can include a dispersant in an amount bounded by any two of the aforementioned endpoints.For example, the polishing composition may be about 0.5% by weight to about 20% by weight, for example, about 0.5% by weight to about 19% by weight, about 0.5% by weight to about 18% by weight, about 0.5% by weight to about 17% by weight, about 0.5% by weight to about 16% by weight, about 0.5% by weight to about 15% by weight, about 0.5% by weight to about 14% by weight, about 0.5% by weight to about 13% by weight, about 0.5% by weight to about 12% by weight, about 0.5% by weight to about 11% by weight, about 0.5% by weight to about 10% by weight, about 1% by weight to about 15% by weight, about 1% by weight to about 14% by weight, about 1% by weight to about 13% by weight, about 1% by weight to about 12% by weight, about 1% by weight to about 11% by weight, about 1% by weight to about 10% by weight, about 2% by weight to about 15% by weight, about 2% by weight to about 14% by weight, about 2% by weight to about 13% by weight, about 2% by weight to about 12% by weight, about 2% by weight to about 11% by weight, about 2% by weight to about 10% by weight, about 3% by weight to about 15% by weight, about 3% by weight to about 14% by weight, about 3% by weight to about 13% by weight, about 3% by weight to about 12% by weight, about 3% by weight to about 11% by weight, or about 3% by weight to about 10% by weight of dispersant.

[0017] The polishing composition comprises water. The water can be any suitable water, for example, deionized water or distilled water. In some embodiments, the polishing composition can further comprise one or more organic solvents in combination with water. For example, the polishing composition can further comprise a hydroxyl solvent, for example, methanol or ethanol, a ketone solvent, an amide solvent, a sulfoxide solvent, a sulfoxide solvent, etc. Preferably, the polishing composition comprises pure water.

[0018] The polishing composition can have any suitable pH, for example, a pH of about 1 to about 7. Typically, the polishing composition can have a pH of about 2 or more, for example, about 2.2 or more, about 2.4 or more, about 2.6 or more, about 2.8 or more, or about 3 or more. Alternatively, or in addition, the polishing composition can have a pH of about 6 or less, for example, about 5 or less, about 4.5 or less, about 4 or less, about 3.5 or less, or about 3 or less. Thus, the polishing composition can have a pH within a range bounded by any two of the aforementioned endpoints. For example, the polishing composition can have a pH of about 2 to about 6, for example, about 2 to about 5, about 2 to about 4, about 2.5 to about 5, about 2.5 to about 4.5, about 2.5 to about 4, or about 2 to about 4.5.

[0019] The polishing composition optionally comprises a mineral acid. Non-limiting examples of suitable mineral acids include nitric acid, sulfuric acid, and phosphoric acid.

[0020] The polishing composition can further include a base to adjust the pH of the polishing composition. Non-limiting examples of suitable bases include sodium hydroxide, potassium hydroxide, and ammonium hydroxide.

[0021] The polishing composition optionally further comprises an oxidizing agent. The oxidizing agent can be any suitable oxidizing agent. In certain embodiments, the oxidizing agent comprises ferric ions. The ferric ions can be provided by any suitable ferric ion source. In some embodiments, the oxidizing agent can comprise a salt of a metal. For example, the ferric ions can be provided by a ferric salt comprising an inorganic anion such as nitrate ions (e.g., ferric nitrate), cyanide ions (e.g., ferric anion), and the like. The oxidizing agent can also comprise, but is not limited to, organic iron (III) compounds such as acetates, acetylacetonates, citrates, gluconates, oxalates, phthalates, and succinates, and mixtures thereof. In other embodiments, the oxidizing agent can be an oxy-containing oxidizing agent. Non-limiting examples of suitable oxy-containing oxidizing agents include organic peroxide compounds such as hydrogen peroxide, persulfates, bromates, iodates, perbromates, periodates, persulfates, peracetic acid, oxone, and the like.

[0022] The polishing composition can include any suitable amount of oxidizing agent. For example, the polishing composition can include about 1 ppm or more, for example, about 5 ppm or more, about 25 ppm or more, about 50 ppm or more, about 75 ppm or more, or about 100 ppm or more of oxidizing agent. Alternatively, or in addition, the polishing composition can include about 2500 ppm (about 2.5 wt%) or less of oxidizing agent, for example, about 2000 ppm or less, about 1500 ppm or less, about 1000 ppm or less, about 500 ppm or less, or about 250 ppm or less. Unless otherwise stated, the term ppm is meant to reflect parts per million by weight. For example, 1000 ppm is equivalent to 1 wt%.

[0023] When the optional oxidizing agent includes hydrogen peroxide, the hydrogen peroxide can be present in the polishing composition in any suitable amount. For example, the polishing composition can include from about 0.1% to about 10% by weight of hydrogen peroxide, such as from about 0.5% to about 10% by weight, or from about 0.5% to about 5% by weight.

[0024] The polishing composition optionally further comprises an amino acid. The amino acid may be any suitable amino acid. Non-limiting examples of suitable amino acids include glycine, alanine, lysine, and arginine. The polishing composition may contain any suitable amount of the amino acid. For example, the polishing composition may contain about 0.1% by weight to about 5% by weight (about 100 ppm to about 5000 ppm), for example, about 0.1% by weight to about 4% by weight, about 0.1% by weight to about 3% by weight, about 0.1% by weight to about 2% by weight, or about 0.1% by weight to about 1% by weight of the amino acid.

[0025] When the polishing composition includes ferric ions (i.e., Fe(III) ions), the polishing composition optionally further includes a stabilizer for ferric ions. The stabilizer for ferric ions can be any suitable stabilizer for ferric ions. A non-limiting example of a stabilizer for ferric ions is malonic acid. The polishing composition can contain any suitable amount of the stabilizer for ferric ions. For example, the polishing composition can include about 0.1 wt % to about 2 wt %, e.g., about 0.1 wt % to about 1.8 wt %, about 0.1 wt % to about 1.6 wt %, about 0.1 wt % to about 1.4 wt %, about 0.1 wt % to about 1.2 wt %, or about 0.1 wt % to about 1 wt % of the stabilizer for ferric ions.

[0026] The polishing composition can be prepared by any suitable technique, many of which are known to those skilled in the art. The polishing composition can be prepared in a batch or continuous process. In general, the polishing composition can be prepared by combining its components in any order. As used herein, the term "component" includes individual components (e.g., abrasive, dispersant, optional oxidizing agent, optional amino acid, etc.) as well as any combination of components (e.g., abrasive, dispersant, optional oxidizing agent, optional amino acid, etc.).

[0027] For example, the abrasive can be dispersed in water. The dispersant can then be added and mixed by any method that can incorporate the components into the polishing composition. The optional oxidizing agent and the optional amino acid can be added at any time during the preparation of the polishing composition. The polishing composition can be prepared before use by adding one or more components, such as an oxidizing agent, for example, hydrogen peroxide, to the polishing composition immediately before use (e.g., within about 1 minute before use, or within about 1 hour before use, or within about 7 days before use). The polishing composition can also be prepared by mixing the components on the surface of the substrate during the polishing operation.

[0028] The polishing composition may be supplied as a one-package system including the abrasive, dispersant, optional oxidizing agent, optional amino acid, and water. Alternatively, the abrasive may be supplied as a dispersion in water in a first container, and the dispersant, optional oxidizing agent, and optional amino acid may be supplied in a second container, either in dry form, or in aqueous solution or dispersion. When the oxidizing agent includes hydrogen peroxide, the hydrogen peroxide is desirably supplied separately from the other components of the polishing composition, and is combined with the other components of the polishing composition immediately prior to use, for example, by the end user (e.g., within one week prior to use, within one day prior to use, within one hour prior to use, within ten minutes prior to use, or within one minute prior to use). The components in the first or second container may be in dry form, and the components in the other container may be in the form of an aqueous dispersion. Furthermore, it is also suitable for the components in the first and second containers to have different pH values, or to have substantially similar or equal pH values. Other two-container, or three or more container combinations of components of the polishing composition are within the knowledge of those skilled in the art.

[0029] The polishing composition of the present invention can also be provided as a concentrate, which is intended to be diluted with an appropriate amount of water before use.In such an embodiment, the concentrate of the polishing composition can contain abrasives, dispersants, optional oxidizing agents, optional amino acids, and water, with or without optional hydrogen peroxide, in amounts such that upon dilution of the concentrate with an appropriate amount of water, and upon addition of optional hydrogen peroxide if it is not already present in an appropriate amount, each component of the polishing composition will be present in the polishing composition in an amount within the appropriate range listed above for each component.For example, the abrasives, dispersants, optional oxidizing agents, and optional amino acids can each be present in an amount that is about 2 times (e.g., about 3 times, about 4 times, or about 5 times) higher than the concentration listed above for each component, so that when the concentrate is diluted with an equal amount of water (e.g., 2 equivalents of water, 3 equivalents of water, or 4 equivalents of water, respectively) together with a suitable amount of optional hydrogen peroxide, each component will be present in the polishing composition in an amount within the range listed above for each component. Moreover, as will be understood by one of ordinary skill in the art, the concentrate can contain a suitable proportion of water that will be present in the final polishing composition to ensure that the other components are at least partially or completely dissolved in the concentrate.

[0030] The present invention also provides a method for chemically mechanically polishing a substrate, comprising: (i) providing a substrate; (ii) providing a polishing pad; (iii) providing a chemical-mechanical polishing composition described herein; (iv) contacting the substrate with the polishing pad and the chemical-mechanical polishing composition; and (v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of a surface of the substrate, thereby polishing the substrate.

[0031] More specifically, the present invention also provides a method for chemically mechanically polishing a substrate, the method comprising: (i) providing a substrate; (ii) providing a polishing pad; and (iii) a chemical mechanical polishing composition comprising: (a) about 0.05% to about 10% by weight of an abrasive; and (b) a dispersant, the dispersant being a linear or branched C2-C 10Also provided is a method including: providing a chemical-mechanical polishing composition having a pH of about 2 to about 6, the chemical-mechanical polishing composition including (a) a dispersing agent, the dispersing agent being an alkylene diol; and (c) water; (iv) contacting a substrate with the polishing pad and the chemical-mechanical polishing composition; and (v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to grind at least a portion of a surface of the substrate to polish the substrate.

[0032] The substrate to be polished using the method of the present invention can be any suitable substrate, particularly a substrate comprising at least one metal layer. The metal can be any suitable metal, for example, the metal can comprise, consist essentially of, or consist of a metal selected from tungsten, aluminum, nickel-phosphorus, copper, ruthenium, cobalt, and combinations thereof. In a preferred embodiment, the metal is tungsten. A preferred substrate comprises at least one layer, particularly an exposed layer, on the surface of the substrate for polishing that comprises, consists essentially of, or consists of a metal, such that at least a portion of the metal on the surface of the substrate is ground away (i.e., removed) to polish the substrate. In some embodiments, the substrate comprises at least one layer of metal and at least one layer of silicon oxide. In some preferred embodiments, the substrate comprises at least one layer of tungsten and at least one layer of silicon oxide. The polishing compositions and methods of the present invention are suitable for use in the so-called damascene polishing process for forming circuit lines on a suitable substrate, such as silicon oxide, by etching the silicon oxide surface to form the circuit lines, and then overcoating the substrate with a layer of tungsten to fill the circuit lines. A substrate comprising insulated tungsten circuit lines on a silicon oxide substrate is formed by at least chemically mechanically polishing the tungsten overcoat to expose the silicon oxide substrate surface, thus producing insulated tungsten lines on the substrate. In some embodiments, the substrate thus formed may be subjected to one or more subsequent polishing and / or cleaning steps to produce a finished substrate.

[0033] Thus, in a preferred embodiment, the substrate comprises a tungsten layer on the surface of the substrate, and at least a portion of the tungsten layer is ground to polish the substrate. In another preferred embodiment, the substrate comprises a silicon oxygen layer on the surface of the substrate, and at least a portion of the silicon oxide layer is ground to polish the substrate. In another preferred embodiment, the substrate comprises a silicon nitrogen layer on the surface of the substrate, and at least a portion of the silicon nitride layer is ground to polish the substrate. The substrate may comprise one or more of a tungsten layer on the surface of the substrate, a silicon oxygen layer on the surface of the substrate, and a silicon nitride layer on the surface of the substrate, and at least a portion of one or more of the tungsten layer, the silicon oxygen layer, and the silicon nitride layer is ground to polish the substrate.

[0034] The polishing composition of the present invention desirably exhibits a reduction in the growth of average grain size over time. It is believed that the growth of average grain size is caused by the aggregation of grinding particles, which increases the total number of grains with relatively large grain size. It is believed that the grains with relatively large grain size lead to an increase in the generation of micro-scratches in the substrate being polished, which micro-scratches can lead to an increase in defects in the substrate. When used to polish substrates, particularly substrates containing tungsten and silicon oxide, the polishing composition of the present invention further desirably exhibits a satisfactory removal rate while providing improved polishing performance in terms of substrate surface quality, particularly in reducing the generation of micro-scratches in the substrate being polished.

[0035] The polishing method of the present invention is particularly suitable for use with a chemical mechanical polishing (CMP) apparatus.Normally, a CMP apparatus comprises a platen that moves during use and has a speed resulting from an orbital, linear or circular motion, a polishing pad that contacts the platen and moves with the platen during operation, and a carrier that contacts and moves against the surface of the polishing pad to hold the substrate so that it is polished.The polishing of the substrate is carried out by placing the substrate in contact with the polishing pad and the polishing composition of the present invention, and then moving the polishing pad against the substrate to grind at least a portion of the substrate to polish the substrate.

[0036] The substrate can be planarized or polished with the chemical mechanical polishing composition together with any suitable polishing pad (e.g., polishing surface). Suitable polishing pads include, for example, woven and nonwoven polishing pads. Furthermore, suitable polishing pads can include any suitable polymer of various density, hardness, thickness, compressibility, ability to rebound when compressed, and compressive elasticity. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, co-formed products thereof, and mixtures thereof.

[0037] Desirably, the CMP apparatus further includes an in-situ polishing endpoint detection system, many of which are known in the art. Techniques for inspecting and monitoring the polishing process by analyzing light or other radiation reflected from the surface of the workpiece are known in the art. Such methods are disclosed, for example, in U.S. Pat. No. 5,196,353, U.S. Pat. No. 5,433,651, U.S. Pat. No. 5,609,511, U.S. Pat. No. 5,643,046, U.S. Pat. No. 5,658,183, U.S. Pat. No. 5,730,642, U.S. Pat. No. 5,838,447, U.S. Pat. No. 5,872,633, U.S. Pat. No. 5,893,796, U.S. Pat. No. 5,949,927, and U.S. Pat. No. 5,964,643. Desirably, inspecting or monitoring the progress of the polishing process on the workpiece being polished allows for the determination of the polishing endpoint, i.e., when to terminate the polishing process on a particular workpiece.

[0038] Desirably, the polishing compositions of the present invention exhibit reduced microscratches on substrates polished therewith.The polishing compositions of the present invention also desirably exhibit improved storage stability.

[0039] The present invention can be characterized by the following embodiments.

[0040] Embodiment (1) In embodiment (1), there is provided a chemical mechanical polishing composition comprising: (a) about 0.05% by weight to about 10% by weight of an abrasive; (b) A dispersant having a linear or branched C2-C 10 a dispersant which is an alkylene diol; (c) water, A chemical-mechanical polishing composition having a pH of about 1 to about 7 is provided.

[0041] (2) In embodiment (2), there is provided the chemical mechanical polishing composition of embodiment (1), wherein the composition comprises about 1 wt % to about 5 wt % of the abrasive.

[0042] (3) In embodiment (3), there is provided the chemical mechanical polishing composition of embodiment (1) or embodiment (2), wherein the composition comprises about 2.5 wt % to about 3.5 wt % of an abrasive.

[0043] (4) In embodiment (4), there is provided a chemical mechanical polishing composition according to any one of embodiments (1) to (3), wherein the abrasive is selected from treated alumina, colloidal silica, fumed silica, surface-modified silica, and combinations thereof.

[0044] (5) In embodiment (5), there is provided the chemical mechanical polishing composition of any one of embodiments (1) to (4), wherein the abrasive is colloidal silica.

[0045] (6) In embodiment (6), there is provided the chemical mechanical polishing composition of embodiment (5), wherein the colloidal silica has an average particle size of about 10 nm to about 100 nm.

[0046] (7) In embodiment (7), there is provided the chemical mechanical polishing composition of embodiment (6), wherein the colloidal silica has an average particle size of about 30 nm to about 70 nm.

[0047] (8) In embodiment (8), there is provided the chemical mechanical polishing composition of any one of embodiments (1) to (7), wherein the composition comprises about 0.5% by weight to about 20% by weight of a dispersant.

[0048] (9) In embodiment (9), there is provided the chemical mechanical polishing composition of any one of embodiments (1) to (8), wherein the composition comprises about 1 wt % to about 15 wt % of a dispersant.

[0049] (10) In embodiment (10), there is provided the chemical mechanical polishing composition of any one of embodiments (1) to (9), wherein the composition comprises about 3% to about 10% by weight of a dispersant.

[0050] (11) In embodiment (11), there is provided the chemical-mechanical polishing composition of any one of embodiments (1) to (10), wherein the chemical-mechanical polishing composition has a pH of about 2 to about 5.

[0051] (12) In embodiment (12), there is provided the chemical-mechanical polishing composition of any one of embodiments (1) to (11), wherein the chemical-mechanical polishing composition has a pH of about 2 to about 4.

[0052] (13) In embodiment (13), there is provided the chemical mechanical polishing composition of any one of embodiments (1) to (12), wherein the dispersant is a linear or branched C2 to C7 alkylene diol.

[0053] (14) In embodiment (14), the chemical mechanical polishing composition of any one of embodiments (1) to (13) is provided, wherein the dispersant is a linear or branched C4 to C7 alkylene diol.

[0054] (15) In embodiment (15), there is provided a chemical mechanical polishing composition according to any one of embodiments (1) to (14), wherein the dispersant is 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, or a combination thereof.

[0055] (16) In embodiment (16), the chemical mechanical polishing composition of any one of embodiments (1) to (15) is provided, wherein the abrasive is 1,4-butanediol.

[0056] (17) In embodiment (17), the dispersant is a linear C2-C 10 The chemical mechanical polishing composition of embodiment (1) is provided, wherein the alkylene diol is an alkylene diol.

[0057] (18) In embodiment (18), there is provided a method for chemically mechanically polishing a substrate, comprising the steps of: (i) providing a substrate; (ii) providing a polishing pad; (iii) A chemical-mechanical polishing composition comprising: (a) about 0.05% by weight to about 10% by weight of an abrasive; (b) A dispersant having a linear or branched C2-C 10 a dispersant which is an alkylene diol; (c) water, providing a chemical-mechanical polishing composition having a pH of about 2 to about 6; (iv) contacting the substrate with a polishing pad and a chemical-mechanical polishing composition; (v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of a surface of the substrate to polish the substrate.

[0058] (19) In embodiment (19), the method of embodiment (18) is provided, wherein the composition comprises about 1% to about 5% by weight of an abrasive.

[0059] (20) In embodiment (20), the method of embodiment (18) or embodiment (19) is provided, wherein the composition comprises about 2.5% to about 3.5% by weight of an abrasive.

[0060] (21) In embodiment (21), the method of any one of embodiments (18) to (20) is provided, wherein the abrasive is selected from treated alumina, colloidal silica, fumed silica, surface-modified silica, and combinations thereof.

[0061] (22) In embodiment (22), the method of any one of embodiments (18)-(21) is provided, wherein the abrasive is colloidal silica.

[0062] (23) In embodiment (23), the method of embodiment (22) is provided, wherein the colloidal silica has an average particle size of about 10 nm to about 100 nm.

[0063] (24) In embodiment (24), the method of embodiment (23) is provided, wherein the colloidal silica has an average particle size of about 30 nm to about 70 nm.

[0064] (25) In embodiment (25), the method of any one of embodiments (18) to (24) is provided, wherein the composition comprises about 0.5% to about 20% by weight of a dispersant.

[0065] (26) In embodiment (26), the method of any one of embodiments (18) to (25) is provided, wherein the composition comprises about 1% by weight to about 15% by weight of a dispersant.

[0066] (27) In embodiment (27), the method of any one of embodiments (18) to (26) is provided, wherein the composition comprises about 3% to about 10% by weight of a dispersant.

[0067] (28) In embodiment (28), the method of any one of embodiments (18) to (27) is provided, wherein the chemical-mechanical polishing composition has a pH of about 2 to about 5.

[0068] (29) In embodiment (29), the method of any one of embodiments (18) to (28) is provided, wherein the chemical-mechanical polishing composition has a pH of about 2 to about 4.

[0069] (30) In embodiment (30), the method of any one of embodiments (18) to (29) is provided, wherein the dispersant is a linear or branched C2-C7 alkylene diol.

[0070] (31) In embodiment (31), the method of any one of embodiments (18) to (30) is provided, wherein the dispersant is a linear or branched C4 to C7 alkylene diol.

[0071] (32) In embodiment (32), the method of any one of embodiments (18) to (31) is provided, wherein the dispersant is 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, or a combination thereof.

[0072] (33) In embodiment (33), the method of any one of embodiments (18) to (32) is provided, wherein the dispersant is 1,4-butanediol.

[0073] (34) In embodiment (34), the dispersant is a linear C2-C 10 The method of embodiment (18) is provided wherein the alkylene diol is an alkylene diol.

[0074] (35) In embodiment (35), the method according to any one of embodiments (18) to (34) is provided, in which the substrate includes a tungsten layer on a surface of the substrate, and at least a portion of the tungsten layer is ground to polish the substrate.

[0075] (36) In embodiment (36), a method according to any one of embodiments (18) to (35) is provided, in which the substrate further comprises a silicon-oxygen layer on a surface of the substrate, and at least a portion of the silicon-oxygen layer is ground to polish the substrate.

[0076] (37) In embodiment (37), a method according to any one of embodiments (18) to (36) is provided, in which the substrate further comprises a silicon nitrogen layer on a surface of the substrate, and at least a portion of the silicon nitrogen layer is ground to polish the substrate. EXAMPLES

[0077] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

[0078] Example 1 This example demonstrates the stability of a polishing composition containing colloidal silica and a dispersant in accordance with an embodiment of the present invention.

[0079] Polishing Compositions 1A-1G contained 3 wt. % colloidal silica (Akzo Nobel CJ2-2), 1335 ppm malonic acid, 500 ppm glycine, 618 ppm 10% ferric nitrate solution, 2.5 wt. % Kathlon™ hydrogen peroxide, and various amounts of 1,4-butanediol (i.e., dispersant) at a pH of 3, 4, or 5, as described in Table 1. The average particle size was determined immediately after preparation of the polishing compositions and after storage of the polishing compositions at 45° C. for 1, 2, and 3 weeks using a particle sizer available from Malvern Panalytical (Malvern, UK). The results are shown graphically in FIG. 1. [Table 1]

[0080] As is evident from the results shown in Figure 1, the particles present in Polishing Compositions 1A-1C, which contained colloidal silica and no dispersant and had an initial average particle size of about 80 nm, showed an increase in average particle size to about 120 nm (Polishing Composition 1A), about 160 nm (Polishing Composition 1B), and about 200 nm (Polishing Composition 1C) after the polishing compositions were stored for 3 weeks at 45°C. These increases in particle size occurred at pH 3 (Polishing Composition 1A), pH 4 (Polishing Composition 1B), and pH 5 (Polishing Composition 1C), respectively.

[0081] Polishing compositions 1F and 1G, which contained 10 wt% dispersant at pH values ​​of 3 and 5, respectively, and had an initial average particle size of about 120 nm, showed an increase in average particle size to about 130 nm (polishing composition 1F) and about 150 nm (polishing composition 1G) after storage at 45° C. for 3 weeks. The smallest increase in average particle size (about 8%) after storage at 45° C. for 3 weeks was observed for polishing composition 1F, which contained colloidal silica and 10 wt% dispersant at a pH of 3. As demonstrated by these results, the presence of a dispersant significantly inhibits aggregation and therefore prevents an increase in average particle size. For example, polishing composition 1A, which had a pH of 3 and no dispersant, showed an increase in particle size of about 50%, while polishing composition 1F, which had a pH of 3 and 10 wt% dispersant, showed an increase in particle size of about 8%.

[0082] Example 2 This example demonstrates the stability of a polishing composition comprising alumina surface-treated with a sulfonic acid-containing polymer and a dispersant in accordance with an embodiment of the present invention.

[0083] Polishing Compositions 2A-2G contained 250 ppm of alumina surface-treated with a sulfonic acid-containing polymer, 1080 ppm of malonic acid, 1000 ppm of lysine, 1000 ppm of arginine, 500 ppm of ferric nitrate, 0.5 wt. % Kathlon™ hydrogen peroxide, and various amounts of 1,4-butanediol (i.e., dispersant) at a pH of 2 or 4, as described in Table 2. The average particle size was determined immediately after preparation of the polishing compositions and after storage at 45° C. for 1, 2, and 3 weeks using a particle sizer available from Malvern Panalytical (Malvern, UK). The results are shown graphically in FIG. 2. [Table 2]

[0084] As can be seen from the results shown in Figure 2, the particles present in Polishing Compositions 2A and 2B, which contained alumina surface-treated with a sulfonic acid-containing polymer and did not contain a dispersant, and had an initial average particle size of about 150 nm, showed an increase in average particle size to about 950 nm (Polishing Composition 2A) and about 800 nm (Polishing Composition 2B) after three weeks of storage at 45°C. These increases in particle size occurred at pH 2 (Polishing Composition 2A) and pH 4 (Polishing Composition 2B), respectively. The increases in average particle size of Polishing Compositions 2A and 2B were about 630% and 530%, respectively.

[0085] At pH values ​​of 2 or 4, polishing compositions 2C-2G containing 0.5-10 wt. % dispersant showed substantially no increase in particle size after 3 weeks of storage at 45° C. As demonstrated by these results, the presence of a dispersant in a polishing composition containing alumina surface-treated with a sulfonic acid-containing polymer substantially completely inhibits aggregation and thus prevents an increase in average particle size.

[0086] Example 3 This example demonstrates the removal rates of tungsten and silicon oxide provided by polishing compositions containing an abrasive and a dispersant according to embodiments of the present invention.

[0087] Polishing Compositions 3A-3E contained 3 wt.% colloidal silica (average particle size of 75 nm), 1500 ppm of 10 wt.% ferric nitrate solution, 3240 ppm malonic acid, 2000 ppm lysine, and 15 ppm Kathlon™ at a pH of 4.0. Polishing Composition 3A (comparative) did not contain a dispersant. Polishing Compositions 3B-3E (inventive) further contained 1,4-butanediol (i.e., a dispersant) at 1 wt.%, 3 wt.%, 7 wt.%, and 9 wt.%, respectively. Separate substrates containing blanket layers of tungsten or silicon oxide were polished with the five polishing compositions (Polishing Compositions 3A-3E). After polishing, the removal rates of tungsten and silicon oxide were determined. The results are listed in Table 3. [Table 3]

[0088] As is evident from the results set forth in Table 3, increasing the amount of 1,4-butanediol dispersant from 0 wt. % in Polishing Composition 3A to 9 wt. % in Polishing Composition 3E provides a beneficial effect, slightly reducing the removal rates of tungsten and silicon oxide, while the presence of the dispersant significantly inhibits particle size growth, as demonstrated in Example 1 herein.

[0089] All references cited in this specification, including publications, patent applications, and patents, are herein incorporated by reference to the same extent as if each reference was individually and specifically indicated to be incorporated by reference and was set forth in its entirety herein.

[0090] The use of the terms "a" and "an" and "the" and "at least one" and similar referents in the context of describing the invention (particularly in the context of the claims below) should be construed to encompass both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The use of the term "at least one" following a list of one or more items (e.g., "at least one of A and B") should be construed to mean one item selected from the listed items (A or B), or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise indicated. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of individually referring to each separate value within the range, unless otherwise indicated herein, and each separate value is incorporated herein as if it were individually recited herein. All methods described herein can be carried out in any suitable order, unless otherwise indicated herein or clearly contradicted by context. Any and all examples provided herein, or the use of exemplary words (e.g., "etc.") are intended merely to make the invention clearer, and do not limit the scope of the invention unless otherwise asserted. No language in this specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0091] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those skilled in the art upon reading the foregoing description. The inventors expect those skilled in the art to employ such variations as appropriate, and the inventors intend for the invention to be carried out otherwise than as specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, the present invention encompasses any combination of the above in all possible variations thereof, unless otherwise indicated herein or clearly contradicted by context. The present disclosure also includes the following: <Aspect 1> 1. A chemical mechanical polishing composition comprising: (a) about 0.05% by weight to about 10% by weight of an abrasive; (b) A dispersant having a linear or branched C 2 ~C 10 a dispersant which is an alkylene diol; (c) water, The chemical-mechanical polishing composition has a pH of about 1 to about 7. <Aspect 2> 2. The chemical mechanical polishing composition of claim 1, wherein the composition comprises about 2% to about 5% by weight of the abrasive. <Aspect 3> The chemical mechanical polishing composition of claim 1, wherein the abrasive is selected from the group consisting of treated alumina, colloidal silica, fumed silica, surface-modified silica, and combinations thereof. <Aspect 4> The chemical mechanical polishing composition of claim 1, wherein the abrasive is colloidal silica. <Aspect 5> 5. The chemical mechanical polishing composition of embodiment 4, wherein the colloidal silica has an average particle size of about 10 nm to about 100 nm. <Aspect 6> 2. The chemical mechanical polishing composition of claim 1, wherein the composition comprises about 0.5% to about 20% by weight of the dispersant. <Aspect 7> 2. The chemical mechanical polishing composition of claim 1, wherein the chemical mechanical polishing composition has a pH of about 2 to about 5. <Aspect 8> The dispersant is a linear or branched C 2 ~C 7 The chemical mechanical polishing composition of embodiment 1, wherein the alkylene diol is an alkylene diol. <Aspect 9> The chemical mechanical polishing composition of claim 1, wherein the dispersing agent is selected from 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and combinations thereof. <Aspect 10> The chemical mechanical polishing composition of claim 1, wherein the dispersing agent is 1,4-butanediol. <Aspect 11> The dispersant is a linear C 2 ~C 10 The chemical mechanical polishing composition of embodiment 1, wherein the alkylene diol is an alkylene diol. <Aspect 12> 1. A method for chemically mechanically polishing a substrate, comprising: (i) providing a substrate; (ii) providing a polishing pad; (iii) A chemical-mechanical polishing composition comprising: (a) about 0.05% by weight to about 10% by weight of an abrasive; (b) A dispersant having a linear or branched C 2 ~C 10 a dispersant which is an alkylene diol; (c) water, providing a chemical-mechanical polishing composition having a pH of about 2 to about 6; (iv) contacting the substrate with the polishing pad and the chemical-mechanical polishing composition; (v) moving the polishing pad and the chemical-mechanical polishing composition relative to the substrate to abrade at least a portion of a surface of the substrate to polish the substrate. <Aspect 13> 13. The method of claim 12, wherein the composition comprises about 1% to about 5% by weight of the abrasive. <Aspect 14> 13. The method of claim 12, wherein the abrasive is selected from treated alumina, colloidal silica, fumed silica, surface-modified silica, and combinations thereof. <Aspect 15> 13. The method of claim 12, wherein the abrasive is colloidal silica. <Aspect 16> 16. The method of claim 15, wherein the colloidal silica has an average particle size of about 10 nm to about 100 nm. <Aspect 17> 13. The method of claim 12, wherein the composition comprises about 0.5% to about 20% by weight of the dispersing agent. <Aspect 18> 13. The method of claim 12, wherein the chemical-mechanical polishing composition has a pH of about 2 to about 5. <Aspect 19> The dispersant is a linear or branched C 2 ~C 7 13. The method of claim 12, wherein the alkylene diol is an alkylene diol. <Aspect 20> 13. The method of claim 12, wherein the dispersing agent is selected from 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and combinations thereof. <Aspect 21> 13. The method of claim 12, wherein the dispersing agent is 1,4-butanediol. <Aspect 22> 13. The method of claim 12, wherein the substrate comprises a tungsten layer on a surface of the substrate, and at least a portion of the tungsten layer is ground to polish the substrate.

Claims

1. 1. A chemical mechanical polishing composition comprising: (a) 0.05% to 10% by weight of an abrasive; (b) a dispersant selected from 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, and combinations thereof; (c) water, having a pH of 1 to 7; A chemical-mechanical polishing composition, wherein the abrasive is alumina surface-treated with an anionic polymer.

2. 10. The chemical mechanical polishing composition of claim 1, wherein the composition comprises from 2% to 5% by weight of the abrasive.

3. 10. The chemical mechanical polishing composition of claim 1, wherein the composition comprises from 0.5% to 20% by weight of the dispersing agent.

4. 10. The chemical-mechanical polishing composition of claim 1, wherein the chemical-mechanical polishing composition has a pH of 2-5.

5. 2. The chemical mechanical polishing composition of claim 1, wherein the dispersing agent is 1,4-butanediol.

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