Chemical mechanical polishing composition and method for preventing polishing pad groove clogging

Abstract

To provide a chemical mechanical polishing composition and a method for preventing polishing pad groove clogging.SOLUTION: An aqueous based chemical mechanical polishing composition for polishing a semiconductor substrate includes: an abrasive having bimodally distributed colloidal silica particles which include elongated colloidal silica particles; polyvinyl alcohol which is 80% to 90% (including 90%) hydrolyzed; an electrolyte; and a pH greater than 7. A method of polishing a semiconductor substrate to planarize the substrate is also provided. The aqueous based chemical mechanical polishing composition and the method inhibit polishing pad groove clogging during chemical mechanical polishing of the semiconductor substrate.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention is directed to a chemical mechanical polishing composition and a method for preventing polishing pad groove blockage during chemical mechanical polishing and planarization. More specifically, the present invention is directed to a chemical mechanical polishing composition and a method for preventing polishing pad groove blockage during chemical mechanical polishing and planarization, where the chemical mechanical polishing composition includes water, an abrasive having a bimodal distribution of colloidal silica particles including elongated colloidal silica particles, 80% to 90% or less hydrolyzed polyvinyl alcohol, an electrolyte, a pH greater than 7, and good conductivity. [Background technology]

[0002] In the manufacture of integrated circuits and other electronic devices, multiple layers of conductive, semiconducting, and dielectric materials are deposited on or removed from the surface of a semiconductor wafer. Thin layers of conductive, semiconducting, and dielectric materials can be deposited by a variety of deposition techniques. Common deposition techniques in modern processing include physical vapor deposition (PVD), also known as sputtering, chemical vapor deposition (CVD), plasma-assisted chemical vapor deposition (PECVD), and electrochemical plating (ECP).

[0003] As layers of material are subsequently deposited and removed, the top surface of the wafer becomes non-planar. Subsequent semiconductor processing (e.g., metallization) requires the wafer to have a flat surface, so the wafer needs to be planarized. Planarization is useful for removing undesirable surface topography and surface defects, such as rough surfaces, granulations, crystal lattice damage, scratches, and contaminated layers or materials.

[0004] Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize substrates, such as semiconductor wafers. In conventional CMP, a wafer is mounted on a carrier assembly and placed in contact with a polishing pad in a CMP apparatus. The carrier assembly provides a controllable pressure to the wafer, pressing it against the polishing pad. The pad is moved (e.g., rotated) relative to the wafer by an external driving force. At the same time, a polishing composition ("slurry") or other polishing fluid is provided between the wafer and the polishing pad. The wafer surface is then polished and made planar by the chemical and mechanical action of the pad surface and the slurry.

[0005] There are many complexities involved in CMP: each type of material requires a unique polishing composition, properly designed polishing pads, optimized process settings for both polishing and post-CMP cleaning, and other factors that must be individually tailored for the polishing application of the specific material.

[0006] A variety of abrasive particles can be used in the polishing or planarization process. Colloidal silica particles of various sizes are often the abrasive of choice for polishing and planarizing semiconductor wafers. In addition to size, the particles can have a variety of shapes. Colloidal silica particles having round, elliptical, elongated or nodular shapes are common. Elongated colloidal silica particles are becoming a popular choice for use in alkaline ILD slurries due to their enhanced polishing efficiency compared to silica particles of other shapes.

[0007] Some of the most popular slurries for polishing and planarizing semiconductor wafers contain elongated colloidal silica particles, often in combination with other shaped colloidal silica particles. However, the main problem associated with such slurries is that they can cause pad groove clogging of some types of commercial polishing pads after extensive polishing periods. Such pad grooves are typically circular in shape. The result of pad groove clogging is the substantial elimination of polishing uniformity performance. This is indicated by the gradual change in polishing uniformity on the semiconductor wafer surface due to localized blockage of slurry transport during polishing.

[0008] 1A-C are photographs of the polished surface (center-edge) of a VisionPad™ 5000 polyurethane polishing pad after polishing a semiconductor wafer with an aqueous chemical mechanical polishing slurry consisting of water and about 12 wt. % Optiplane™ 1735 abrasive colloidal silica particles. The colloidal silica particles include a mixture of spherical colloidal silica particles and elongated and nodular particles. The pH of the polishing slurry was about 10.7. The annular groove had a width of 8 mm, a depth of 2 mm, an outer edge radius of 340 mm, and an inner edge radius of 335 mm. Polishing was performed on an Applied Materials Mirra® polishing machine with a slurry flow rate of 100 mL / min, a down force of about 34.5 kPa, a platen speed of 108 rpm, and a carrier speed of 102 rpm.

[0009] 1A-C illustrate the degree of blockage of an annular groove set in the polishing surface of a pad base proceeding from near the center of the pad as shown in FIG. 1A, where the blockage of the groove decreases slightly toward the section distal to the center as shown in FIG. 1B, and then shows substantial blockage of the groove toward the periphery of the pad as shown in FIG. 1C, where the blockage of the groove is substantially zero. This illustrates the gradual change in polishing uniformity. The more the annular groove is blocked, the less uniform the planarization of the semiconductor wafer surface becomes. Summary of the Invention [Problem to be solved by the invention]

[0010] Therefore, there is a need for a method to inhibit chemical mechanical polishing slurry and polishing pad groove blockage and at the same time maintain good polishing and planarization performance. [Means for solving the problem]

[0011] The present invention provides a chemical-mechanical polishing composition that includes water, an abrasive having a bimodal distribution of colloidal silica particles including elongated colloidal silica particles, 80% to 90% or less hydrolyzed polyvinyl alcohol, an electrolyte, and a pH greater than 7.

[0012] The present invention further provides a chemical-mechanical polishing composition that includes water, an abrasive having a bimodal distribution of colloidal silica particles including elongated colloidal silica particles, 80% to 89% hydrolyzed polyvinyl alcohol, an electrolyte, a pH adjuster, and a pH of 8 to 12.

[0013] The present invention further provides a chemical-mechanical polishing composition that includes water, an abrasive having a bimodal distribution of colloidal silica particles including elongated colloidal silica particles, 87%-89% hydrolyzed polyvinyl alcohol, an electrolyte, a pH adjuster, and a pH of 9-11.

[0014] The present invention also provides a substrate comprising silicon oxide; a chemical-mechanical polishing composition comprising water, an abrasive having a bimodal distribution of colloidal silica particles comprising elongated colloidal silica particles, less than 90% hydrolyzed polyvinyl alcohol, an electrolyte, and a pH greater than 7; A method for chemical mechanical polishing of a substrate is provided, comprising: providing a chemical mechanical polishing pad having a polishing surface and grooves; creating dynamic contact at an interface between the polishing surface of the chemical mechanical polishing pad and the substrate with a downward force of 20 to 100 kPa; and dispensing a chemical mechanical polishing composition onto the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate, wherein some of the silicon oxide is removed from the substrate.

[0015] Surprisingly, a method of polishing a silicon dioxide-containing substrate with a chemical mechanical polishing composition comprising water, an abrasive having a bimodal distribution of colloidal silica particles including elongated colloidal silica particles, 80% hydrolyzed to 90% hydrolyzed polyvinyl alcohol, an electrolyte, and a pH greater than 7, and a polishing pad containing grooves, inhibits undesirable blockage of grooves in the polishing pad during chemical mechanical polishing. Inhibiting groove blockage substantially prevents gradual changes in polishing uniformity over a semiconductor wafer surface due to localized blockage of slurry transport, thus enabling improved polishing and planarization performance. [Brief description of the drawings]

[0016] [Figure 1A] 1 is a photograph taken with a Nikon SMZ 1500 stereo microscope of a section near the center of the polishing surface of a VP5000 polyurethane polishing pad after polishing illustrating annular groove blockage with a conventional polishing slurry. [Figure 1B] 1 is a photograph taken with a Nikon SMZ 1500 stereo microscope of a section distal to the center of the polishing surface of an IC1000™ polyurethane polishing pad after polishing illustrating annular groove blockage with a conventional polishing slurry. [Figure 1C] 1 is a photograph taken with a Nikon SMZ 1500 stereo microscope of a section on the periphery of the polishing surface of an IC1000™ polyurethane polishing pad after polishing illustrating an annular groove that is substantially free of polishing slurry. [Figure 2A] 1 is a photograph taken with an iPhone of the polished surface of a VP5000 polyurethane pad after polishing with a slurry of the present invention illustrating a plurality of annular grooves that do not contain abrasive slurry. [Figure 2B] 1 is a photograph taken with a Nikon SMZ 1500 stereo microscope of a section of the polished surface of a VP5000 polyurethane polishing pad after polishing with a slurry of the present invention illustrating a plurality of annular grooves that do not contain abrasive slurry. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] As used throughout this specification, the following abbreviations have the following meanings unless the context dictates otherwise: L = liter; mL = milliliter; kPa = kilopascal; Å = angstrom; nm = nanometer; cm = centimeter; mm = millimeter; g = grams; min = minutes; rpm = revolutions per minute; wt% = weight percent; RR = removal rate; PVA = polyvinyl alcohol; PS = polishing slurry of the present invention; PC = comparative polishing slurry; Mw = weight average molecular weight g / mole; k = 1000; mS = millisiemens; "~" = about; and VP5000 = VisionPad™ 5000 polyurethane polishing pad.

[0018] The term "chemical mechanical polishing" or "CMP" refers to a process in which a substrate is polished by chemical and mechanical forces alone, and is distinguished from electrochemical-mechanical polishing (ECMP), in which an electrical bias is applied to the substrate. The term "TEOS" refers to silicon oxide formed from the decomposition of tetraethyl orthosilicate (Si(OC2H5)4). The term "elongated" in reference to colloidal silica abrasive particles means that the abrasive particles have a length that is greater than their width. The term "spherical" in reference to colloidal silica particles means that the abrasive particles are rounded or circular in shape. The term "bimodal distribution" refers to a set of scores having two (2) peaks or modes around which the values ​​tend to cluster such that the frequency first increases and then decreases around each peak, and if the peak heights are not equal, the higher peak or peak is the major mode and the lower peak is the minor mode (for colloidal silica abrasive particles, it can be represented in a Cartesian plane as the relative weight of the particles on the Y axis versus the particle size in microns on the X axis, where the X axis is linear or preferably log). The term "multimodal" refers to having or including several modes, modalities, or maxima. The term "unimodal" or "monomodal" means that the distribution has only one peak. The term "average value" refers to a value that falls between (close to) the first and second modes, and is the average value of the entire Cartesian plane graph of the relative particle weight versus particle size in microns. As used herein, the term "dominant" refers to a mode of bimodal particle distribution of abrasive colloidal silica particles that has an overwhelming influence or is the most important mode of bimodal particle distribution of abrasive colloidal silica particles during chemical mechanical polishing of a substrate. The terms "composition" and "slurry" are used interchangeably throughout this specification. The term "halide" refers to chloride, bromide, fluoride, and iodide. The term "electrolyte" refers to a substance that splits into ions (particles with an electric charge) when it is dissolved in water. The term "Siemens (S)" is the International Standard (SI) for electrical conductivity.The terms "a" and "an" refer to both the singular and the plural. All percentages are by weight unless otherwise specified. All numerical ranges are inclusive and combinable in any order, except where it is logical that such numerical ranges are constrained to add up to 100%.

[0019] The chemical mechanical polishing composition of the present invention comprises elongated and spherical colloidal silica abrasive particles having a bimodal particle distribution. Preferably, the colloidal silica used contains at least one of precipitated silica and aggregated silica. Preferably, the bimodal particle distribution of the colloidal silica abrasive particles exhibits a first mode with a first average particle size maximum of 50-100 nm, more preferably 60-90 nm, even more preferably 70-90 nm, and most preferably 80-90 nm. Preferably, the elongated colloidal silica abrasive particles exhibit a second mode with a second average particle size maximum of 100-200 nm, more preferably 120-180 nm, even more preferably 130-170 nm, even more preferably 140-165 nm, and most preferably 140-150 nm. The first mode reflects spherical particles, while the second mode is indicative of elongated particles. The second mode dominates the bimodal particle distribution.

[0020] Preferably, the mean value of the bimodal particle distribution is 95 to 200 nm, more preferably 110 to 180 nm, most preferably 135 to 165 nm. Preferably, the mean value falls between the first and second modes (close to the second mode).

[0021] The chemical mechanical polishing composition of the invention preferably comprises 5-30 wt% colloidal abrasive silica particles, of which at least 50 wt% are elongated colloidal abrasive silica particles. More preferably, the chemical mechanical polishing composition of the invention comprises 10-30 wt% colloidal abrasive silica particles, of which 50-95 wt% are elongated abrasive silica particles, and even more preferably, the chemical mechanical polishing composition comprises 10-20 wt% colloidal abrasive silica particles, of which 70-90 wt% are elongated colloidal silica abrasive particles.

[0022] The colloidal silica abrasive particles of the present invention are a mixture of a first population of colloidal silica abrasive particles having an average particle size preferably between 75 and 80 nm and a second population of colloidal silica abrasive particles having an average particle size preferably between 110 and 140 nm.

[0023] An example of a commercially available colloidal silica abrasive that contains a bimodal distribution of elongated colloidal silica abrasive particles is Klebosol™ 1635 colloidal silica manufactured by Merck KgAA, Darmstadt, Germany, available from DuPont.

[0024] The chemical mechanical polishing composition of the present invention includes polyvinyl alcohol. The polyvinyl alcohol is formed from the hydrolysis of polyvinyl acetate by methods known in the art. Preferably, the degree of hydrolysis of the polyvinyl alcohol is 80% to 90% or less, more preferably, the polyvinyl alcohol is 80% to 89% hydrolyzed, and most preferably, the polyvinyl alcohol is 87% to 89% hydrolyzed. The degree of hydrolysis refers to the amount of free hydroxyl groups present on the polyvinyl alcohol compared to the sum of the free hydroxyl groups and the acetylated hydroxyl groups.

[0025] Preferably, the 80% to 90% hydrolyzed polyvinyl alcohol of the present invention has a weight average molecular weight of 9000 g / mol or more, more preferably 10,000 to 200,000 g / mol, even more preferably 10,000 to 190,000 g / mol, even more preferably 12,000 to 150,000 g / mol, and most preferably 30,000 to 50,000 g / mol.

[0026] Preferably, polyvinyl alcohol is contained in the chemical mechanical polishing composition of the invention in an amount of 0.001 to 0.05 wt %, more preferably 0.0025 to 0.01 wt %, and most preferably 0.005 to 0.01 wt %.

[0027] One or more electrolytes (inorganic or organic) are included in the chemical mechanical polishing composition of the present invention to provide a desired conductivity. Preferably, the conductivity of the chemical mechanical polishing composition of the present invention is 4 mS / cm or more, more preferably 4 to 7 mS / cm, and most preferably 5 to 7 mS / cm.

[0028] Inorganic electrolytes include, but are not limited to, alkali metal salts such as sodium chloride and potassium chloride, ammonium salts, alkali metal hydroxides such as sodium and potassium hydroxide, alkali metal carbonates such as sodium carbonate and potassium, alkali metal bicarbonates such as sodium bicarbonate, phosphates such as potassium phosphate, nitrates such as potassium nitrate, sulfates such as potassium sulfate, and mixtures of the foregoing.

[0029] Organic electrolytes include, but are not limited to, choline chloride, carboxylic acids such as citric acid and acetic acid, quaternary ammonium salts such as benzyltrimethylammonium chloride, phenyltrimethylammonium chloride, phenyltrimethylammonium bromide and phenyltrimethylammonium hydroxide, etc. Mixtures of the foregoing can be included in the chemical mechanical polishing composition of the present invention.

[0030] The inorganic and organic electrolytes are included in the chemical mechanical polishing composition in an amount sufficient to obtain the desired conductivity, preferably at least 0.01 wt % or more, more preferably 0.01 to 1 wt %, and even more preferably 0.05 to 0.25 wt %.

[0031] The chemical mechanical polishing composition used in the chemical mechanical polishing method of the present invention has a pH of >7, preferably 8-12, and more preferably 9-11.

[0032] Optionally, the chemical mechanical polishing composition can include one or more pH adjusters to maintain the pH within a desired range. Preferably, the pH adjusters are selected from one or more of sodium hydroxide, potassium hydroxide, ammonium hydroxide, ammonium halides, and nitrates.

[0033] Optionally, the chemical-mechanical polishing composition contains a biocide, such as KORDEK™ MLX (9.5-9.9% methyl-4-isothiazolin-3-one, 89.1-89.5% water, and ≦1.0% related reaction products) or KATHON™ ICP III (KATHON and KORDEK are trademarks of International Flavors & Fragrances, Inc.), which contains the active ingredients 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, respectively, manufactured by International Flavors & Fragrances, Inc.

[0034] When a biocide is included in the chemical mechanical polishing composition of the present invention, the biocide is included in an amount of 0.0001 wt % to 0.1 wt %, preferably 0.001 wt % to 0.05 wt %, more preferably 0.001 wt % to 0.01 wt %, and even more preferably 0.001 wt % to 0.005 wt %.

[0035] The water contained in the chemical mechanical polishing composition used in the chemical mechanical polishing method of the present invention is preferably at least one of deionized water and distilled water to limit incidental impurities.

[0036] Preferably, the chemical-mechanical polishing composition comprises water, a bimodal distribution of colloidal silica particle abrasive (wherein the colloidal silica particles are elongated and spherical), 80% to 90% hydrolyzed polyvinyl alcohol, an electrolyte, optionally a biocide, optionally a pH adjuster, and a pH greater than 7.

[0037] More preferably, the chemical-mechanical polishing composition comprises water, a bimodal distribution of colloidal silica particle abrasive (wherein the colloidal silica particles are elongated and spherical), 87-89% hydrolyzed polyvinyl alcohol, an electrolyte, optionally a biocide, optionally a pH adjuster, and a pH of 8-12.

[0038] More preferably, the chemical-mechanical polishing composition comprises water, a bimodal distribution of colloidal silica particle abrasive (wherein the colloidal silica particles are elongated and spherical), polyvinyl alcohol that is 87-89% hydrolyzed and has a weight average molecular weight of 9000 g / mol or greater, an electrolyte, optionally a biocide, optionally a pH adjuster, and a pH of 9-11.

[0039] Most preferably, the chemical-mechanical polishing composition comprises water, a bimodal distribution of colloidal silica particle abrasive (wherein the colloidal silica particles are elongated and spherical), polyvinyl alcohol having a weight average molecular weight of 87-89% hydrolyzed and 12,000-150,000 g / mol, an electrolyte (conductivity of 4 mS / cm or greater), optionally a biocide, optionally a pH adjuster, and a pH of 9-11.

[0040] The substrates polished by the chemical mechanical polishing method of the present invention contain silicon oxides, including, but not limited to, borophosphosilicate glass (BPSG), plasma enhanced tetraethyl orthosilicate (PETEOS), silicon oxide formed from the decomposition of tetraethyl orthosilicate (Si(OC2H5)4), also known as TEOS, thermal oxide, undoped silicate glass, and high density plasma (HDP) oxide.

[0041] The chemical mechanical polishing pad used in the chemical mechanical polishing method of the present invention for removing silicon oxide can be any suitable polishing pad known in the art. The chemical mechanical polishing pad can be optionally selected from woven and non-woven polishing pads. The chemical mechanical polishing pad can be made of any suitable polymer of various density, hardness, thickness, compressibility, and elasticity. The chemical mechanical polishing pad used in the polishing method of the present invention includes a groove on the polishing surface, such as an annular groove. The dimensions of the groove can vary. All the grooves on a given pad can have the same dimensions, or the grooves can vary in dimensions. For example, in one embodiment, the annular groove can have a width of 3-8 mm, a depth of 0.5-2 mm, an outer edge radius of 335-340 mm, and an inner edge radius of 330-335 mm. In another embodiment, the groove can have a width of 3-8 mm, a depth of 0.5-2 mm, an outer edge radius of 35-45 mm, and an inner edge radius of 30-40 mm.

[0042] Commercially available polishing pads that can be used to practice the method of the present invention include, but are not limited to, VISIONPAD 5000 / K7™ polyurethane polishing pad, IC1000™ polyurethane polishing pad, and IC1010™ polyurethane polishing pad (available from Rohm and Haas Electronic Materials CMP, LLC).

[0043] The chemical mechanical polishing composition used in the chemical mechanical polishing method of the present invention allows operation at a low nominal polishing down force pad pressure, for example, 20-35 kPa on a 300 mm polisher with a platen speed of 93-123 revolutions per minute, a carrier speed of 87-117 revolutions per minute, and a chemical mechanical polishing composition flow rate of 40-300 mL / min.

[0044] The chemical mechanical polishing composition and method of the present invention suppresses clogging of the grooves of the chemical mechanical polishing pad, allowing uniform planarization of semiconductor wafers with a significant removal rate of TEOS from the wafer surface. For example, Figures 2A-B are photographs of the polished surface of a VP5000 polyurethane polishing pad after polishing a semiconductor wafer with an aqueous chemical mechanical polishing slurry of the present invention consisting of water and 11.5 wt% KLEBOSOL™ 1635 abrasive colloidal silica particles, 0.005 wt% 89% hydrolyzed polyvinyl alcohol, 0.055 benzyltrimethylammonium chloride, 0.055 wt% choline chloride, and 0.164 wt% potassium carbonate, and a pH of 10.7. The colloidal silica particles comprised about 90% elongated colloidal silica particles, with the remainder being spherical particles.

[0045] The annular groove had a width of 8 mm, a depth of 2 mm, an outer edge radius of 340 mm, and an inner edge radius of 335 mm. Polishing was performed on an Applied Materials Mirra® polisher with a slurry flow rate of 100 mL / min, a down force of approximately 34.5 kPa, a platen speed of 108 rpm, and a carrier speed of 102 rpm.

[0046] 2A-B illustrate annular grooves set in the polishing surface of a pad base. FIG. 2A shows a plurality of annular grooves in the polishing surface of a polishing pad base after polishing, which shows that the grooves are all free of polishing slurry. FIG. 2B is a closer image of the polishing pad surface in which the grooves are free of polishing slurry. The chemical mechanical polishing compositions and methods of the present invention have demonstrated unexpected inhibition of polishing pad groove blockage. EXAMPLES

[0047] The following examples are intended to illustrate the invention but not to limit its scope.

[0048] In the following examples, unless otherwise indicated, temperature and pressure conditions are ambient temperature and standard pressure.

[0049] The following raw materials were used in the examples that follow:

[0050] The polishing removal rate experiments were performed on 160 20.3 cm blanket wafers. An Applied Materials Mirra® polishing machine was used for the examples. A VISIONPAD 5000 / K7™ polyurethane polishing pad with grooves 40 mil (1 mm) deep, 18 mil (0.45 mm) grooves and 120 mil (3 mm) pitch (available from Rohm and Haas Electronic Materials CMP, Inc.) was used to perform the polishing examples at a down force of 31.7 kPa (4.6 psi), a chemical mechanical polishing slurry composition flow rate of 100 mL / min, a table rotation speed of 108 rpm and a carrier rotation speed of 102 rpm. The pad grooves were visually inspected for cleanliness before and after polishing. The TEOS removal rate was determined by measuring the film thickness before and after polishing using a KLA-Tencor FX200 metrology tool. The polishing slurry was maintained at a pH of about 10.7 during chemical mechanical polishing. Aqueous 2 wt% KOH was added to each slurry to maintain the desired pH. Slurry conductivity was measured with a YSI 3200 conductivity meter (available from YSI Incorporated, Yellow Springs, OH 45387 USA). The mean and mode for the abrasive colloidal silica particles were measured using a CPS Disc Centrifuge™ nanoparticle size analyzer (available from CPS Instruments, Inc., Stuart, Florida).

[0051] Example 1 Comparative Chemical Mechanical Polishing Compositions An aqueous chemical mechanical polishing slurry was prepared as shown in Table 1 below.

[0052] [Table 1]

[0053] Abrasive: Klebosol™ 1635 bimodal colloidal silica particles containing 50% by weight elongated particles, the remainder being spherical, ellipsoidal, or nodular, available from DuPont, manufactured by Merck KgAA, Darmstadt, Germany.

[0054] [Table 2]

[0055] Klebosol™ 1635 bimodal colloidal silica particles, together with organic and inorganic electrolytes, caused significant VISIONPAD 5000 / K7™ polyurethane polishing pad groove blockage. The annular groove of the polishing pad appeared substantially as in Figures 2A-B. In contrast, the annular groove of the comparative polishing pad appeared substantially as shown in Figures 1A-B.

[0056] Example 2 Chemical mechanical polishing composition, TEOS RR and suppression of pad groove clogging Aqueous chemical mechanical polishing slurries were prepared as shown in Tables 3A and 3B below. 11.5% by weight of Klebosol™ 1635 colloidal silica abrasive was included in each chemical mechanical polishing slurry. The Klebosol™ 1635 colloidal silica abrasive included 50% by weight of elongated particles.

[0057] [Table 3]

[0058] [Table 4]

[0059] [Table 5]

[0060] Polishing results showed that the combination of elongated colloidal silica abrasive and 80-89% hydrolyzed PVA with Mw of 9000-186000 g / mol significantly prevented groove blockage in VISIONPAD 5000 / K7™ polyurethane polishing pads. In addition, the TEOS removal rates were as good, if not better, than those of the polishing compositions PC-1-PC-6 of Example 1 above, which excluded PVA.

[0061] Although PC-7 showed good TEOS removal rate, about 16 grooves were blocked, indicating that 99% hydrolyzed PVA with Mw of 146000-186000 g / mol was detrimental to inhibiting groove blocking of VISIONPAD 5000 / K7™ polyurethane polishing pads.

[0062] Example 3 Chemical Mechanical Polishing Compositions Using Elongated vs. Spherical Colloidal Silica Particles, TEOS RR, and Inhibition of Pad Groove Blockage An aqueous chemical mechanical polishing slurry was prepared as shown in Table 5 below.

[0063] [Table 6]

[0064] Klebosol™ 1501-50 colloidal silica abrasive contained over 80% by weight spherical particles, the remainder being elongated, ellipsoidal or nodular, and was manufactured by Merck KgAA, Darmstadt, Germany, available from DuPont.

[0065] [Table 7]

[0066] Unimodal PC-8 had a higher TEOS removal rate than bimodal PS-11 and PS-12 with electrolyte and 80% hydrolyzed PVA, but PS-11 and PS-12 still showed high TEOS removal rates.More importantly, PC-8 had some undesirable groove clogging, while PS-11 and PS-12 did not show any clogging.

Claims

1. A chemical-mechanical polishing composition comprising water, an abrasive having a bimodal distribution of colloidal silica particles including elongated colloidal silica particles, 80% to 90% or less hydrolyzed polyvinyl alcohol, an electrolyte, and a pH greater than 7.

2. 2. The chemical-mechanical polishing composition of claim 1, wherein the polyvinyl alcohol is 80 to 89 percent hydrolyzed.

3. 3. The chemical-mechanical polishing composition of claim 2, wherein the polyvinyl alcohol is 87 to 89 percent hydrolyzed.

4. 2. The chemical mechanical polishing composition of claim 1, wherein the polyvinyl alcohol that is 80% to 90% hydrolyzed has a weight average molecular weight of 9000 g / mol or more.

5. 5. The chemical mechanical polishing composition of claim 4, wherein the weight average molecular weight is from 12,000 to 150,000 g / mol.

6. 2. The chemical mechanical polishing composition of claim 1, wherein the amount of 80% to 90% or less hydrolyzed polyvinyl alcohol is 0.001 to 0.01 weight percent.

7. 10. The chemical mechanical polishing composition of claim 1, wherein the chemical mechanical polishing composition has a conductivity of 4 mS / cm or greater.

8. 2. The chemical mechanical polishing composition of claim 1, wherein the pH is from 8 to 12.

9. 2. The chemical mechanical polishing composition of claim 1, wherein the bimodal distribution of elongated colloidal silica particles has a first mode having a first particle size maximum of 50 to 100 nm and a second mode having a second particle size maximum of 100 to 200 nm.

10. providing a substrate comprising silicon oxide; providing a chemical-mechanical polishing composition comprising water, an abrasive having a bimodal distribution of colloidal silica particles comprising elongated colloidal silica particles, 80% to 90% or less hydrolyzed polyvinyl alcohol, an electrolyte, optionally a biocide, optionally a surfactant, optionally a pH adjuster, and a pH greater than 7; providing a chemical mechanical polishing pad having a polishing surface and grooves; creating dynamic contact at an interface between the polishing surface of the chemical mechanical polishing pad and the substrate with a downward force of 20-35 kPa; and dispensing the chemical mechanical polishing composition onto the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate.

16. A method for chemical mechanical polishing of a substrate, comprising:

Images