Tungsten CMP compositions containing sulfur-containing anionic surfactants

Abstract

The chemical-mechanical polishing composition for tungsten CMP consists of, consists essentially of, or comprises a liquid carrier, cationic abrasive particles dispersed therein, an iron-containing accelerator, a tungsten etch inhibitor, a sulfur-containing anionic surfactant, and has a pH of less than about 5.

Description

[Technical Field]

[0001] Background of the Invention

[0001] Chemical-mechanical polishing (CMP) compositions and methods for polishing (or planarizing) the surface of a substrate are well known. Polishing compositions (also called polishing slurries, CMP slurries, or CMP compositions) for polishing various metallic (e.g., tungsten) and non-metallic (e.g., silicon oxide) layers on semiconductor substrates can include abrasive particles suspended in an aqueous solution and various chemical additives, such as oxidizers, chelating agents, catalysts, topography control agents, and buffers. [Background technology]

[0002]

[0002] In a conventional CMP operation, a substrate (wafer) to be polished is mounted on a carrier, which is mounted on a carrier assembly and positioned in contact with a polishing pad in a CMP polishing tool. The carrier assembly provides a controlled pressure to the substrate against the polishing pad. The substrate and pad are moved relative to one another by an external driving force. The relative motion of the substrate and pad abrades and removes a portion of material (such as tungsten) from the surface of the substrate, thereby polishing the substrate. Polishing of the substrate by the relative motion of the pad and substrate can be further enhanced by the chemical activity of the polishing composition and / or the mechanical activity of an abrasive suspended in the polishing composition.

[0003] As is well known, there is a strong demand for continued miniaturization in the semiconductor industry. This miniaturization reduces device feature sizes and places more stringent planarization requirements on commercial CMP processes. The industry is seeking CMP compositions (e.g., tungsten CMP compositions) that improve planarity without sacrificing throughput or increasing costs. Summary of the Invention

[0004] A chemical-mechanical polishing composition for use in tungsten CMP operations is disclosed. The composition consists of, consists essentially of, or comprises a liquid carrier, cationic abrasive particles dispersed in the liquid carrier, an iron-containing accelerator, a tungsten etch inhibitor, and a sulfur-containing anionic surfactant. The composition has a pH of less than about 5. DETAILED DESCRIPTION OF THE INVENTION

[0005]

[0005] A chemical-mechanical polishing composition for polishing tungsten is disclosed. In one embodiment, the composition includes a liquid carrier and cationic abrasive particles (such as cationic colloidal silica particles) dispersed therein. The polishing composition may further include an iron-containing accelerator, a tungsten etch inhibitor, and a sulfur-containing anionic surfactant. Methods of using the disclosed composition for polishing tungsten-containing substrates are also disclosed.

[0006] It will be appreciated that the disclosed CMP compositions can be advantageously utilized in bulk tungsten removal CMP operations (sometimes referred to in the art as first-step tungsten CMP operations). Bulk removal operations typically require high tungsten removal rates and low tungsten etching rates. The disclosed CMP compositions can also be advantageously utilized in single-step tungsten CMP operations. The disclosed polishing compositions have been found to advantageously provide high tungsten removal rates, as well as improved planarity and reduced patterned oxide loss. Thus, the compositions can provide improved topography control, such as improved erosion and dishing on device wafers.

[0007] The disclosed polishing compositions generally comprise abrasive particles suspended in a liquid carrier. The liquid carrier is used to facilitate application of the abrasive particles and chemical additives to the surface of the substrate being polished (e.g., planarized). The liquid carrier can comprise any suitable carrier (e.g., solvent), including lower alcohols (e.g., methanol, ethanol, etc.), ethers (e.g., dioxane, tetrahydrofuran, etc.), water, and mixtures thereof. The liquid carrier preferably consists of, or consists essentially of, deionized water.

[0008] The abrasive particles can include virtually any suitable cationic abrasive particles, including, for example, alpha alumina particles, silica particles, and / or aluminum-doped silica particles. By cationic, we mean that the abrasive particles are positively charged at the pH of the polishing composition. In preferred embodiments, the abrasive particles can include cationic silica particles, such as cationic fumed silica particles or cationic colloidal silica particles. Most preferred are cationic colloidal silica particles. As used herein, the term colloidal silica particles refers to silica particles prepared by wet processes, rather than the pyrolytic or flame hydrolysis processes used to produce fumed silica. It will be understood that colloidal silica particles and fumed silica particles are generally structurally different particles. Colloidal silica can be precipitated silica or condensation-polymerized silica and can be prepared using any method known to those skilled in the art, such as sol-gel processes or silicate ion exchange. Condensation-polymerized silica particles are often prepared by condensing Si(OH)4 to form substantially spherical particles. A preferred embodiment includes colloidal silica particles.

[0009] As is well known to those skilled in the art, colloidal silica particles can be agglomerated or non-agglomerated. Non-agglomerated particles are individual, separate particles that are spherical or nearly spherical in shape, but can also have other shapes (usually elliptical, square, or rectangular in cross section, etc.). Agglomerated particles are particles in which multiple individual particles have joined together to form aggregates of generally irregular shape. Agglomerated colloidal silica particles are disclosed, for example, in commonly assigned U.S. Pat. No. 9,309,442.

[0010]

[0010] The charge on silica particles is commonly referred to in the art as zeta potential (or electrokinetic potential). As known to those skilled in the art, the zeta potential of a particle refers to the potential difference between the charge of the ions surrounding the particle and the charge of the bulk solution of the polishing composition (e.g., the liquid carrier and any other components dissolved therein). Zeta potential can be obtained using commercially available measuring instruments such as a Malvern Instruments Zetasizer, a Brookhaven Instruments ZetaPlus Zeta Potential Analyzer, and / or a Dispersion Technologies, Inc. electroacoustic spectrometer.

[0011] In an exemplary embodiment, the polishing composition may include cationic silica particles having a positive charge of about 10 mV or more in the polishing composition (e.g., about 15 mV or more, about 20 mV or more, or about 25 mV or more). The cationic silica particles may have a positive charge of about 60 mV or less in the polishing composition (e.g., about 55 mV or less, or about 50 mV or less). It will be understood, therefore, that the positive charge of the cationic silica particles in the polishing composition may be in a range bounded by any of the aforementioned endpoints, for example, from about 10 mV to about 60 mV (e.g., from about 15 mV to about 60 mV, from about 20 mV to about 50 mV, or from about 25 mV to about 50 mV).

[0012]

[0012] Although the disclosed embodiments are not limited in this respect, the cationic silica particles can advantageously have a permanent positive charge. A permanent positive charge means that the positive charge on the silica particles is not easily reversed, for example, by flushing, dilution, filtration, etc. A permanent positive charge can arise, for example, by covalent bonding of the cationic compound to the colloidal silica (e.g., the outer surface of the particle). A permanent positive charge is in contrast to a reversible positive charge that can arise, for example, as a result of electrostatic interactions between the cationic compound and the silica. Nevertheless, as used herein, a permanent positive charge of at least 10 mV means that the zeta potential of the silica particles remains above 10 mV after a three-stage ultrafiltration test, which is described in more detail in commonly assigned U.S. Pat. No. 9,238,754.

[0013]

[0013] Cationic silica particles having a permanent positive charge in the polishing composition can be obtained by treating the particles with at least one aminosilane compound, as disclosed, for example, in commonly owned U.S. Patent Nos. 7,994,057 and 9,028,572. Alternatively, silica particles having a permanent positive charge in the polishing composition can be obtained by incorporating chemical species such as aminosilane compounds into the silica particles, as disclosed in commonly owned U.S. Patent No. 9,422,456.

[0014] Alternatively, the cationic silica particles can be imparted with a non-permanent positive charge, for example, by contact with a cation-containing component (i.e., a positively charged species) in the liquid carrier. The non-permanent positive charge can be achieved, for example, by treating the particles with at least one cation-containing component selected from ammonium salts (preferably quaternary amine compounds), phosphonium salts, sulfonium salts, imidazolium salts, and pyridinium salts.

[0015]

[0015] The abrasive particles in the disclosed embodiments can have virtually any suitable particle size. Particle size of particles suspended in a liquid carrier is defined in the industry using various means. For example, particle size can be defined as the diameter of the smallest sphere surrounding the particle and can be measured using a number of commercially available instruments, including, for example, a CPS Disc Centrifuge, Model DC24000HR (available from CPS Instruments, Praireville, Louisiana), or a Zetasizer® available from Malvern Instruments®. The abrasive particles may have an average particle size of about 10 nm or more (e.g., about 20 nm or more, about 40 nm or more, or about 50 nm or more). The abrasive particles may have an average particle size of about 200 nm or less (e.g., about 180 nm or less, about 160 nm or less, or about 150 nm or less). Thus, the colloidal silica particles can have an average particle size in the range of about 5 nm to about 200 nm (eg, about 20 nm to about 180 nm, about 40 nm to about 160 nm, or about 50 nm to about 150 nm).

[0016]

[0016] The polishing composition can contain virtually any suitable amount of the above-described anionic particles, but preferably contains a low concentration of abrasive particles at the time of use to reduce costs. It will be understood that compositions with a low concentration of abrasive particles at the time of use can be more highly concentrated, potentially further reducing costs. For example, the polishing composition can contain about 0.01 wt% or more (e.g., about 0.02 wt% or more, about 0.03 wt% or more, or about 0.05 wt% or more) abrasive particles at the time of use. The amount of abrasive particles in the polishing composition can contain about 10 wt% or less (e.g., about 2 wt% or less, about 1 wt% or less, about 0.5 wt% or less, about 0.3 wt% or less, or about 0.2 wt% or less) at the time of use. It will therefore be understood that the amount of abrasive particles, at the time of use, can be within a range bounded by any two of the aforementioned endpoints, for example, within a range of about 0.01% to about 10% by weight (e.g., about 0.01% to about 2% by weight, about 0.02% to about 1% by weight, about 0.02% to about 0.5% by weight, or about 0.03% to about 0.3% by weight).

[0017] The disclosed polishing compositions are generally acidic, having a pH of less than 7 (e.g., less than about 5). For example, the pH may be greater than about 1 (e.g., greater than about 1.5, or greater than about 2, or greater than about 2.5). The pH may be less than about 6 (e.g., less than about 5, less than about 4, or less than about 3). Thus, it will be understood that the pH of the polishing composition may be limited by any of the aforementioned endpoints, for example, within a range of about 1 to about 6 (e.g., about 1 to about 5, about 2 to about 5, or about 2 to about 4). To minimize safety and transportation concerns, a pH greater than about 2 is preferred.

[0018] The pH of the polishing composition can be achieved and / or maintained by any suitable means. The polishing composition can include virtually any suitable pH adjuster or buffer system. For example, suitable pH adjusters include nitric acid, sulfuric acid, phosphoric acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, maleic acid, ammonium hydroxide, etc., while suitable buffers can include phosphates, sulfates, acetates, malonates, oxalates, borates, ammonium salts, etc.

[0019] The disclosed compositions further include an iron-containing tungsten polishing accelerator and corresponding stabilizer. As used herein, an iron-containing accelerator is an iron-containing compound that enhances the removal rate of tungsten during tungsten CMP operations. For example, the iron-containing accelerator may include a soluble iron-containing catalyst, such as those disclosed in U.S. Patent Nos. 5,958,288 and 5,980,775. Such iron-containing catalysts may be soluble in a liquid carrier and include, for example, ferric (iron III) or ferrous (ferric) compounds, such as iron nitrate, iron sulfate, and iron halides, including fluorides, chlorides, bromides, and iodides; organic iron compounds, such as perchlorates, perbromates, and periodates, and iron acetates; carboxylic acids; acetylacetonates; citrates; gluconates; malonates; oxalates; phthalates; succinates; and mixtures thereof.

[0020] The iron-containing promoter may also include an iron-containing activator (e.g., a free radical-generating compound) or iron-containing catalyst bound (e.g., coated or bonded) to the surface of the colloidal silica particles, such as those disclosed in U.S. Patent Nos. 7,029,508 and 7,077,880. For example, the iron-containing promoter may bond with silanol groups on the surface of the colloidal silica particles.

[0021] The amount of iron-containing accelerator in the polishing composition can vary depending on the oxidizer and chemical form of the accelerator used. When the oxidizer (described in more detail below) is hydrogen peroxide (or one of its analogs) and a soluble iron-containing catalyst (such as ferric nitrate or ferric nitrate hydrate) is used, the catalyst can be present in the composition in an amount sufficient to provide, at the time of use, a range of about 0.5 to about 3000 ppm Fe, based on the total weight of the composition. The polishing composition can contain about 1 ppm or more Fe (e.g., about 2 ppm or more, about 5 ppm or more, or about 10 ppm or more) at the time of use. The polishing composition can contain about 1000 ppm or less Fe (e.g., about 500 ppm or less, about 200 ppm or less, or about 100 ppm or less) at the time of use. Thus, the polishing composition can contain Fe in a range bounded by any one of the endpoints above. The composition can contain from about 1 to about 1000 ppm (eg, from about 2 to about 500 ppm, from about 5 to about 200 ppm, or from about 10 to about 100 ppm) of Fe at the point of use.

[0022]

[0022] Embodiments of the polishing composition containing an iron-containing accelerator can further include a stabilizer. Without such a stabilizer, the iron-containing accelerator and the oxidizer, if present, may react and cause the oxidizer to rapidly degrade over time. Because the addition of a stabilizer tends to reduce the effectiveness of the iron-containing accelerator, the selection of the type and amount of stabilizer added to the polishing composition can have a significant impact on CMP performance. The addition of a stabilizer can form a stabilizer / accelerator complex that inhibits the accelerator from reacting with the oxidizer, while at the same time allowing the accelerator to maintain sufficient activity to increase the tungsten polishing rate.

[0023] Useful stabilizers include phosphoric acids, organic acids, phosphonate compounds, nitriles, and other ligands that bind to metals to reduce their reactivity toward decomposition of hydrogen peroxide and mixtures thereof. Acid stabilizers can be used in their conjugated form; for example, carboxylate salts can be used in place of carboxylic acids. The term "acid" as used herein to describe useful stabilizers also refers to the conjugate base of an acid stabilizer. The stabilizers can be used alone or in combination to significantly reduce the rate of decomposition of oxidizing agents such as hydrogen peroxide.

[0024] Preferred stabilizers include phosphoric acid, acetic acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid (EDTA), propylenediaminetetraacetic acid (PDTA), and mixtures thereof. Preferred stabilizers can be added to the compositions of the present invention in amounts ranging from about 1 equivalent to about 3.0 weight percent or more (e.g., about 3 to about 10 equivalents) per iron-containing accelerator. As used herein, the term "equivalent per iron-containing accelerator" means one molecule of stabilizer per iron ion in the composition. For example, two equivalents per iron-containing accelerator means two molecules of stabilizer per catalyst ion.

[0025] The polishing composition may optionally further comprise an oxidizing agent. The oxidizing agent can be added to the polishing composition during the slurry preparation process or immediately prior to the CMP operation (e.g., in a tank or slurry distribution system found in semiconductor fabrication facilities common in the industry). Preferred oxidizing agents include inorganic or organic per-compounds. A per-compound, as defined herein, is a compound containing at least one peroxy group (-O--O-) or a compound containing an element in its highest oxidation state. Examples of compounds containing at least one peroxy group include, but are not limited to, hydrogen peroxide and its adducts such as urea hydrogen peroxide and percarbonates, benzoyl peroxide, peracetic acid, organic peroxides such as di-t-butyl peroxide, monopersulfates (SO5 = ), dipersulfate (S2O8 =), and sodium peroxide. Examples of compounds containing elements in their highest oxidation state include, but are not limited to, periodic acid, periodates, perbromic acid, perbromates, perchloric acid, perchlorates, perboric acid, perborates, and permanganates. The most preferred oxidizing agent is hydrogen peroxide.

[0026] The oxidizing agent can be present in the polishing composition at the time of use in an amount ranging from about 0.1 to about 20 wt %. For example, in embodiments in which a hydrogen peroxide oxidizing agent and a soluble iron-containing accelerator are used, the oxidizing agent can be present in the polishing composition at the time of use in an amount ranging from about 0.1 to about 10 wt % (e.g., from about 0.5 to about 5 wt %, or from about 1 to about 5 wt %).

[0027]

[0027] The disclosed polishing composition further comprises at least one compound that inhibits (or further inhibits) the etching of tungsten. Suitable inhibitor compounds are intended to inhibit the conversion of solid tungsten to soluble tungsten compounds while allowing for effective removal of the solid tungsten by the CMP operation. The polishing composition can comprise virtually any suitable inhibitor, such as the inhibitor compounds disclosed in commonly assigned U.S. Patent Nos. 9,238,754; 9,303,188; and 9,303,189.

[0028] Examples of classes of compounds that are useful inhibitors of tungsten metal etching include compounds with nitrogen-containing functional groups, such as nitrogen-containing heterocycles, alkylammonium ions, aminoalkyls, amino acids, etc. Useful aminoalkyl corrosion inhibitors include, for example, hexylamine, tetramethyl-p-phenylenediamine, octylamine, diethylenetriamine, dibutylbenzylamine, aminopropylsilanol, aminopropylsiloxane, dodecylamine, mixtures thereof, and synthetic and natural amino acids, such as, for example, lysine, aspartic acid, tyrosine, glutamine, glutamic acid, cystine, glycine (aminoacetic acid), histidine, and arginine.

[0029] Alternatively and / or additionally, the inhibitor compound may comprise an amine compound in solution in a liquid carrier. The amine compound may comprise a primary amine, a secondary amine, a tertiary amine, or a quaternary amine. The amine compound may further comprise a monoamine, a diamine, a triamine, a tetraamine, or an amine-based polymer having multiple repeating amine groups (e.g., four or more amine groups).

[0030] In certain embodiments, the tungsten etch inhibitor may include a polyamino acid compound. Suitable polyamino acid compounds may include virtually any suitable amino acid monomer group, including, for example, polyarginine, polyhistidine, polyalanine, polyglycine, polytyrosine, polyproline, polyornithine, and polylysine. In certain embodiments, polylysine is a preferred polyamino acid. It will be understood that polylysine may include ε-polylysine and / or α-polylysine, which are composed of D-lysine and / or L-lysine. Thus, polylysine may include α-poly-L-lysine, α-poly-D-lysine, ε-poly-L-lysine, ε-poly-D-lysine, and mixtures thereof. In certain embodiments, the polylysine may be predominantly ε-poly-L-lysine.

[0031] The tungsten etch inhibitor may further (or alternatively) comprise a derivatized polyamino acid (i.e., a cationic polymer comprising derivatized amino acid monomer units). For example, the derivatized polyamino acid may include a derivatized polyarginine, a derivatized polyornithine, a derivatized polyhistidine, a derivatized polylysine, and the like. CMP compositions comprising derivatized polyamino acid compounds are disclosed in U.S. Patent Publication No. 2021 / 0206920.

[0032] In certain advantageous embodiments, the disclosed polishing composition includes an amino acid tungsten etch inhibitor, such as glycine, glutamic acid, lysine, histidine, arginine, aspartic acid, or a mixture thereof, or a polyamino acid tungsten etch inhibitor, such as polyhistidine, polylysine, polyarginine, or a mixture thereof. It will be understood, of course, that the tungsten etch inhibitor can be used in any available form (e.g., the conjugate acid or conjugate base and salt forms can be used instead of or in addition to the acid form). The term "acid" as used in this context to describe useful compounds refers to the acid itself and any form of the acid capable of modifying the titratable functional group by adjusting the pH. Such forms include its conjugate base or acid, and other salts thereof. For example, the term "glutamic acid" refers not only to the amino acid form but also to the conjugate acid formed by protonating the amine functional group. Similarly, "polylysine" refers to the polylysine polyamino acid and its conjugate acid formed by protonating the amine functional group.

[0033] The disclosed polishing compositions can contain virtually any suitable concentration of the tungsten etch inhibitor compound. Generally, the concentration is high enough to provide adequate etch inhibition over a range of oxidizing agent (e.g., hydrogen peroxide) concentrations, but low enough so that the compound is soluble and does not reduce the tungsten polishing rate below an acceptable level. By soluble, we mean that the compound is completely dissolved in the liquid carrier, or that it forms micelles in the liquid carrier, or that it is carried in the micelles.

[0034] The amount of tungsten etch inhibitor generally depends on the type of inhibitor used, the oxidizer used and its concentration, and the chemical form and concentration of the iron-containing accelerator. In certain desirable embodiments, the concentration of the tungsten etch inhibitor at the time of use may be about 10 μM or more (e.g., about 0.1 mM or more, about 0.2 mM or more, about 0.3 mM or more, about 0.5 mM or more, or about 1 mM or more). The concentration of the tungsten etch inhibitor at the time of use may be 50 mM or less (e.g., 40 mM or less, 30 mM or less, 20 mM or less, 15 mM or less, or 10 mM or less). Thus, the concentration of the tungsten etch inhibitor may be within a range limited by any of the aforementioned endpoints. For example, the concentration of the inhibitor at the time of use may be in the range of about 0.1 mM to about 50 mM (eg, about 0.3 mM to about 30 mM, about 0.5 mM to about 20 mM, or about 1 mM to about 10 mM).

[0035]

[0035] In the polishing composition containing a polyamino acid tungsten etching inhibitor (such as polylysine), the polishing composition may contain, for example, about 1 ppm to about 100 ppm by weight (e.g., about 2 ppm to about 50 ppm, or about 3 ppm to about 30 ppm) of the polyamino acid tungsten etching inhibitor at the time of use. In the polishing composition containing an amino acid tungsten etching inhibitor (such as glutamic acid), the polishing composition may contain, for example, about 50 ppm to about 5000 ppm (0.05 wt%) of the amino acid tungsten etching inhibitor at the time of use (e.g., about 100 ppm to about 2500 ppm, or about 150 ppm to about 1500 ppm).

[0036]

[0036] The disclosed embodiments further include sulfur-containing anionic surfactants. By anionic surfactant, we mean that the compound contains a functional group that is negatively charged at a desired pH range (e.g., the pH of the composition). By sulfur-containing, we mean that the anionic surfactant contains at least one sulfur atom, e.g., a sulfate or sulfonate functional group in preferred embodiments. In exemplary embodiments, the sulfur-containing anionic surfactant can be represented by any of the following formulas: TIFF2025531390000001.tif7170 represents an alkyl group, an alkane group, a branched alkyl group, an alkane group, or a cyclic group of less than 14 carbon atoms." In a preferred embodiment, TIFF2025531390000002.tif4170 represents an alkyl or alkane group, or a branched alkyl or alkane group, whose longest linear carbon chain contains from about 4 carbon atoms to about 12 carbon atoms, more preferably from about 6 carbon atoms to about 10 carbon atoms.

[0037] Examples of sulfur-containing anionic surfactants include butanesulfonate, butyl sulfate, pentanesulfonate, pentyl sulfate, hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, heptanesulfonate, heptyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, dodecanesulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof. Of course, it will be understood that, where applicable, the above-mentioned anionic surfactants can be provided as parent acids or as conjugate base salts, or mixtures thereof, containing any suitable positively charged counterion, such as sodium, potassium, or ammonium cations.

[0038] The polishing composition may contain substantially any suitable amount of sulfur-containing anionic surfactant at the time of use. For example, the polishing composition may contain 1 ppm by weight or more (e.g., about 10 ppm by weight or more, about 20 ppm by weight or more, about 30 ppm by weight or more, or about 50 ppm by weight or more) of sulfur-containing anionic surfactant at the time of use. The amount of sulfur-containing anionic surfactant in the composition may be 2,000 ppm by weight or less (e.g., about 1000 ppm by weight or less, about 500 ppm by weight or less, about 300 ppm by weight or less, or about 200 ppm by weight or less) at the time of use. It will be understood, therefore, that the amount of anionic surfactant may be in a range limited by any two of the aforementioned endpoints, for example, from about 1 ppm to about 2,000 ppm by weight (e.g., from about 10 ppm to about 1000 ppm by weight, from about 20 ppm to about 500 ppm by weight, from about 30 ppm to about 300 ppm by weight, or from about 50 ppm to about 200 ppm by weight) at the point of use.

[0039] The disclosed polishing compositions can include virtually any additional chemical additives. For example, the disclosed compositions can include additional tungsten etch inhibitors and topography control agents, dispersants, and biocides. Such additional additives are purely optional. The disclosed embodiments are not so limited and do not require the use of one or more such additives. In embodiments further including a biocide, the biocide may include any suitable biocide, for example, an isothiazolinone biocide known to those skilled in the art.

[0040]

[0040] The polishing composition can be prepared using any suitable technique, many of which are known to those skilled in the art. The polishing composition can be prepared by a batch process or a continuous process. Generally, the polishing composition can be prepared by combining its components in any order. As used herein, the term "component" includes individual components (e.g., colloidal silica, iron-containing accelerator, amine compound, etc.).

[0041] For example, polishing composition components (such as iron-containing accelerators, stabilizers, tungsten etch inhibitors, and / or biocides) may be added directly to a silica dispersion (such as anionic or cationic colloidal silica). The silica dispersion and other components can be blended together using any suitable technique to achieve adequate mixing. Such mixing / mixing techniques are well known to those skilled in the art. If present, an oxidizing agent can be added at any time during the preparation of the polishing composition. For example, the polishing composition can be prepared prior to use (e.g., within about 1 minute, or within about 10 minutes, or within about 1 hour, or within about 1 day, or within about 1 week of the CMP operation) by adding one or more components, such as an oxidizing agent, immediately before the CMP operation. The polishing composition can also be prepared by mixing the components on the surface of the substrate (e.g., on a polishing pad) during the CMP operation.

[0042] The polishing composition can be advantageously supplied as a one-package system containing colloidal silica having the above-described physical properties and other optional components. The oxidizing agent may desirably be supplied separately from the other components of the polishing composition, and may be mixed with the other components of the polishing composition by the end user immediately before use (e.g., within one week, one day, one hour, ten minutes, or one minute before use). Various combinations of other two-container or three-or-more-container components of the polishing composition are within the knowledge of those skilled in the art.

[0043]

[0043] The polishing composition of the present invention can also be provided as a concentrate intended to be diluted with an appropriate amount of water before use. In such embodiments, the polishing composition concentrate can contain an abrasive (e.g., silica), an iron-containing accelerator, a stabilizer, a tungsten etch inhibitor, and an optional biocide in amounts such that, if not already present, upon dilution of the concentrate with an appropriate amount of water and optional oxidizing agent, each component of the polishing composition will be present in the polishing composition in an amount within the appropriate range recited above for each component. For example, colloidal silica and other optional components can each be present in the polishing composition in an amount about 2-fold (e.g., about 3-fold, about 4-fold, about 5-fold, or even about 10-fold) greater than the use concentration recited above for each component, such that upon dilution of the concentrate with an equal amount (e.g., 2 equivalents, 3 equivalents, 4 equivalents, or 9 equivalents, respectively) each component, together with the appropriate amount of oxidizing agent, will be present in the polishing composition in an amount within the range recited above for each component. Additionally, as will be understood by those skilled in the art, the concentrate may include an appropriate proportion of water present in the final polishing composition to ensure that the other components are at least partially or completely dissolved in the concentrate.

[0044] The disclosed polishing compositions can be advantageously used to polish substrates containing a tungsten layer and a dielectric, such as silicon oxide. In such applications, the tungsten layer can be deposited on one or more barrier layers, including, for example, titanium and / or titanium nitride (TiN). The dielectric layer can be a metal oxide, such as a silicon oxide layer derived from tetraethyl orthosilicate (TEOS), a porous metal oxide, a porous or non-porous carbon-doped silicon oxide, a fluorine-doped silicon oxide, glass, an organic polymer, a fluorinated organic polymer, or other suitable high- or low-dielectric-constant insulating layer.

[0045] The polishing method of the present invention is particularly suitable for use in combination with a chemical mechanical polishing (CMP) apparatus. Typically, the apparatus includes a platen that is in motion at the time of use and has a velocity obtained by orbital, linear, or circular motion, a polishing pad that contacts the platen and moves with the platen during the movement, and a carrier that contacts the surface of the polishing pad and moves relative to the surface of the polishing pad to hold a substrate to be polished. The substrate is polished by placing the substrate in contact with the polishing pad and the polishing composition of the present invention, and then moving the polishing pad relative to the substrate to polish at least a portion of the substrate (such as tungsten, titanium, titanium nitride, and / or dielectric materials described herein).

[0046] In certain desirable embodiments, the disclosed polishing compositions can improve planarity with minimal or no loss in throughput. Exemplary polishing compositions achieve high tungsten and barrier removal rates and rapid wafer removal times. Furthermore, the disclosed polishing compositions can reduce erosion and dishing while reducing oxide loss on patterned wafers.

[0047]

[0047] A substrate can be planarized or polished with the chemical mechanical polishing composition using 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 having various densities, hardnesses, thicknesses, compressibility, rebound ability upon compression, and compressive moduli. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, co-forms thereof, and mixtures thereof.

[0048] It will be appreciated that the present disclosure includes numerous embodiments, including but not limited to the following:

[0049]

[0049] In a first embodiment, the chemical mechanical polishing composition comprises, consists of, or essentially consists of a liquid carrier, cationic abrasive particles dispersed in the liquid carrier, an iron-containing accelerator, a tungsten etch inhibitor, and a sulfur-containing anionic surfactant, and has a pH of less than about 5.

[0050] A second embodiment includes the first embodiment, wherein the cationic abrasive particles comprise colloidal silica.

[0051] A third embodiment includes the second embodiment, wherein the colloidal silica particles include an aminosilane compound either internally or bound to the exterior surface of the particles.

[0052]

[0052] A fourth embodiment includes any one of the second to third embodiments, wherein the colloidal silica has a zeta potential greater than about 20 mV.

[0053] A fifth embodiment can include any one of the second through fourth embodiments, including less than about 1 weight percent of colloidal silica particles at the point of use.

[0054] A sixth embodiment includes any one of the first through fifth embodiments, wherein the iron-containing accelerator comprises a soluble iron-containing catalyst, and the composition further comprises a stabilizer bound to the soluble iron-containing catalyst, the stabilizer being selected from the group consisting of phosphoric acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, and mixtures thereof.

[0055]

[0055] A seventh embodiment includes any one of the first to sixth embodiments, wherein the tungsten etch inhibitor is positively charged at the pH of the composition.

[0056]

[0056] An eighth embodiment includes any one of the first to seventh embodiments, and the tungsten etching inhibitor includes an amino acid selected from the group consisting of glycine, glutamic acid, arginine, aspartic acid, lysine, histidine, and mixtures thereof, or a polyamino acid selected from the group consisting of polylysine, polyarginine, polyhistidine, and mixtures thereof.

[0057] A ninth embodiment includes any one of the first to eighth embodiments, wherein the sulfur-containing anionic surfactant is represented by the formula: TIFF2025531390000003.tif7170 Represents an alkyl group, a branched alkyl group, or a cyclic group having less than 14 carbon atoms.

[0058] A tenth embodiment can include the ninth embodiment, wherein: TIFF2025531390000004.tif4170Represents an alkyl group or branched alkyl group having a longest linear carbon chain containing from about 4 carbon atoms to about 12 carbon atoms.

[0059] An eleventh embodiment includes the tenth embodiment, wherein the longest linear carbon chain contains from about 6 carbon atoms to about 10 carbon atoms.

[0060] A twelfth embodiment includes any one of the first to eleventh embodiments, wherein the sulfur-containing anionic surfactant is selected from the group consisting of butane sulfonate, butyl sulfate, pentyl sulfonate, pentyl sulfate, hexane sulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, dodecane sulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

[0061] A thirteenth embodiment includes any one of the first through twelfth embodiments, wherein the sulfur-containing anionic surfactant is selected from the group consisting of hexane sulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

[0062]

[0062] A fourteenth embodiment includes any one of the first to thirteenth embodiments, wherein the weight ratio of the sulfur-containing anionic surfactant at the time of use is about 10 ppm to about 1000 ppm.

[0063]

[0063] A fifteenth embodiment can include any one of the first to fourteenth embodiments, wherein the tungsten etch inhibitor includes about 1 ppm to about 100 ppm by weight of polylysine at the point of use.

[0064] A sixteenth embodiment can include any one of the first to fourteenth embodiments, wherein the tungsten etch inhibitor includes from about 50 ppm to about 5000 ppm by weight of glutamic acid, glycine, lysine, or a mixture thereof at the point of use.

[0065] A seventeenth embodiment includes any one of the first to sixteenth embodiments, having a pH in the range of about 2 to about 4.

[0066]

[0066] An eighteenth embodiment includes any one of the first to seventeenth embodiments, and further includes a hydrogen peroxide oxidizing agent.

[0067] A nineteenth embodiment may include any one of the first to eighteenth embodiments, wherein the sulfur-containing anionic surfactant is selected from the group consisting of butane sulfonate, butyl sulfate, pentyl sulfonate, pentyl sulfate, hexane sulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, dodecane sulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof; the composition comprises from about 10 ppm to about 1000 ppm by weight of the sulfur-containing anionic surfactant; and the tungsten etch inhibitor comprises from about 1 ppm to about 100 ppm by weight of polylysine at the time of use, or from about 50 ppm to about 5000 ppm by weight of glutamic acid, glycine, lysine, or mixtures thereof at the time of use.

[0068] In a twentieth embodiment, a method of chemically mechanically polishing a patterned tungsten-containing substrate includes: (a) contacting the substrate with any one of the polishing compositions described in the first through nineteenth embodiments; (b) moving the polishing composition relative to the substrate; and (c) polishing the substrate to remove a portion of at least one tungsten layer from the substrate, thereby polishing the substrate. Includes:

[0069] The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

[0070] Example 1 Five tungsten polishing compositions (Compositions 1A-1E) were prepared and evaluated. Each composition contained 0.1 weight percent (1000 ppm by weight) colloidal silica having an average particle size of approximately 120 nm and containing a permanent positive charge imparted by surface treatment with an aminosilane as described in Example 7 of U.S. Pat. No. 9,382,450. Each composition further contained 200 weight ppm ferric nitrate nonahydrate (27 ppm Fe), 300 weight ppm malonic acid, 2 weight ppm Kathon LX biocide, and 1 weight percent hydrogen peroxide. The pH of each composition was adjusted to 2.7 using potassium hydroxide. Polishing Composition 1A further contained 10 weight ppm ε-poly-L-lysine. Polishing Composition 1B further contained 10 ppm by weight of ε-poly-L-lysine and 10 ppm by weight of Starquat DCE12,14-HG (StarChem LLC). Polishing Composition 1C further contained 500 ppm by weight of L-glutamic acid. Polishing Compositions 1D and 1E further contained 500 ppm by weight of L-glutamic acid and 100 ppm by weight of sodium ethylhexyl sulfate (1D) or 100 ppm by weight of arginine (1E). Polishing Compositions 1A-1E are further summarized in Table 1A. TIFF2025531390000005.tif62170

[0071]

[0071] The polishing performance of blanket and patterned wafers was evaluated by polishing a 300 mm blanket wafer with a W layer and a Silyb 2 kÅ MIT 754 tungsten-patterned wafer (available from Silyb Wafer Services) on a Reflexion® CMP tool (available from Applied Materials) using Pad 5C from commonly assigned U.S. Patent Publication No. 2021 / 0008687. The polishing process included a platen speed of 80 rpm, a head speed of 89 rpm, and a slurry flow rate of 100 mL / min. The downforce was 2.5 psi until the barrier film was removed (endpoint), then reduced to 1.2 psi for a 25-second overpolish. Ex-situ pad conditioning was applied using a 3M A122 conditioning disk at 6 lbs downforce for 24 seconds.

[0072]

[0072] The polishing performance of the blanket and patterned wafers is summarized in Table 1B. TIFF2025531390000006.tif40170

[0073] As can be seen from the results shown in Table 1B, polishing compositions 1B and 1E (containing Starquat and the arginine supplemental additive) exhibited higher erosion than the control compositions (1A and 1D). Polishing composition 1E exhibited even greater dishing. Polishing composition 1D (containing the sodium ethylhexyl sulfate additive of the present invention) exhibited similar erosion (153 Å vs. 157 Å), reduced dishing (48 Å vs. 92 Å), similar W removal rate (1424 Å / min vs. 1540 Å / min), and reduced patterned oxide loss (14 Å vs. 23 Å) compared to the control (1C). Thus, it is clear that the polishing composition containing the sulfur-containing anionic surfactant of the present invention (sodium ethylhexyl sulfate in this example) exhibited improved overall planarity.

[0074] Example 2 Three tungsten polishing compositions (Compositions 2A-2C) were prepared and evaluated. Each composition contained 0.2 weight percent (2000 ppm by weight) of the colloidal silica described in Example 1 above. Each composition further contained 200 ppm by weight of ferric nitrate nonahydrate (27 ppm Fe), 400 ppm by weight of malonic acid, 10 ppm by weight of ε-poly-L-lysine, 2 ppm by weight of Kathon LX biocide, and 3 percent by weight of hydrogen peroxide. The pH of each composition was adjusted to 2.7 using potassium hydroxide. Polishing Composition 2B further contained 100 ppm by weight of sodium ethylhexyl sulfate. Polishing Composition 2C further contained 100 ppm by weight of L-cysteic acid monohydrate. Polishing Compositions 2A-2C are further summarized in Table 2A. TIFF2025531390000007.tif42170

[0075]

[0075] Patterned wafer polishing performance was evaluated by polishing a Silyb 2 kÅ MIT 754 tungsten-patterned wafer (available from Silyb Wafer Services) with an E6088 polishing pad (available from CMC Materials) on a Reflexion® CMP tool (available from Applied Materials). The polishing process included a platen speed of 80 rpm, a head speed of 89 rpm, a downforce of 3.5 psi, and a slurry flow rate of 100 mL / min. The wafer was polished to endpoint and then overpolished for 15 seconds. The endpoint time (time until tungsten and barrier film were removed) and flag time (time until the tungsten film was removed) were recorded. Ex-situ pad conditioning was applied using a 3M A122 conditioning disk at a downforce of 6 lbs for 24 seconds.

[0076]

[0076] The polishing performance of the patterned wafers is summarized in Table 2B. TIFF2025531390000008.tif35170

[0077] As can be seen from the results shown in Table 2B, Polishing Compositions 2B and 2C (containing sodium ethylhexyl sulfate and L-cysteic acid monohydrate supplemental additives) exhibited less erosion and similar dishing compared to the control composition (2A). Polishing Composition 2B (containing sodium ethylhexyl sulfate) also exhibited reduced patterned oxide loss (51 Å vs. 63 Å). Thus, it is clear that the polishing composition containing the sulfur-containing anionic surfactant of the present invention (in this example, sodium ethylhexyl sulfate) exhibited improved overall planarity. Furthermore, Polishing Composition 2B exhibited similar endpoint and flag times compared to Control Composition 2A, demonstrating that improved overall planarity can be achieved without a loss in throughput. In contrast, Polishing Composition 2C (containing L-cysteic acid monohydrate supplemental additive) exhibited increased patterned oxide loss (79 Å vs. 63 Å) and a significantly longer endpoint time (indicating a slower barrier polishing rate) than the control.

[0078] Example 3 Three tungsten polishing compositions (Compositions 3A-3C) were prepared and evaluated. Each composition contained 0.2 weight percent (2000 ppm by weight) of the colloidal silica described in Example 1 above. Each composition further contained 200 ppm by weight of ferric nitrate nonahydrate (27 ppm Fe), 400 ppm by weight of malonic acid, 10 ppm by weight of ε-poly-L-lysine, 2 ppm by weight of Kathon LX biocide, and 3 percent by weight of hydrogen peroxide. The pH of each composition was adjusted to 2.7 using potassium hydroxide. Polishing Composition 3B further contained 100 ppm by weight of sodium ethylhexyl sulfate. Polishing Composition 3C further contained 100 ppm by weight of sodium decyl sulfate. Polishing Compositions 3A-3C are further summarized in Table 2A. TIFF2025531390000009.tif42170

[0079]

[0079] Patterned wafer polishing performance was evaluated by polishing a Silyb 2 kÅ MIT 754 tungsten-patterned wafer (available from Silyb Wafer Services) with an E6088 polishing pad (available from CMC Materials) on a Mirra® CMP tool (available from Applied Materials). The polishing process was performed at a platen speed of 80 rpm, a head speed of 89 rpm, a downforce of 3.5 psi, and a slurry flow rate of 50 mL / min. The wafer was polished to the endpoint and overpolished for 15 seconds. Ex-situ pad conditioning was applied for 24 seconds at a downforce of 6 lbs using a 3M A122 conditioning disk. TEOS blanket wafers were polished for 60 seconds.

[0080]

[0080] The polishing performance of the patterned wafers is summarized in Table 2B. TIFF2025531390000010.tif35170

[0081] As can be seen from the results shown in Table 3B, polishing compositions 3B and 3C (containing the co-additives ethylhexyl sulfate and decyl sulfate) were found to be less erosive than the control composition (2A). Furthermore, polishing compositions 3B and 3C exhibited similar (or slightly reduced) patterned tungsten removal rates and reduced patterned oxide (TEOS) removal rates (indicating reduced loss of the patterned oxide). Thus, it is clear that polishing compositions containing the sulfur-containing anionic surfactants of the present invention (in this example, ethylhexyl sulfate and sodium decyl sulfate) exhibited improved overall planarity and comparable throughput to the control composition (3A).

[0082] Example 4 The colloidal stability of 15 (or 17 if 12C) tungsten polishing compositions (Compositions 4A-4N) was evaluated. Each composition contained 0.11 weight percent (1100 ppm by weight) of the colloidal silica described in Example 1 above. Each composition further contained 100 ppm by weight of ferric nitrate nonahydrate (14 ppm Fe), 300 ppm by weight of malonic acid, 400 ppm by weight of L-glutamic acid, and 15 ppm by weight of Kathon LX biocide. The pH of each composition was adjusted to 2.5. Each composition further contained a sulfur-containing anionic surfactant in the amount (ppm by weight) listed in Table 4A. The carbon chain length of each anionic surfactant is also listed in Table 4A. TIFF2025531390000011.tif80170

[0083]

[0083] The average particle size and zeta potential of the colloidal silica in each polishing composition was measured using a Zetasizer from Malvern, and the test results are shown in Figure 4B. TIFF2025531390000012.tif80170

[0084] As is evident from the results shown in Table 4B, polishing compositions 4A-4K (containing sulfur-containing anionic surfactants with carbon chain lengths of 12 or less) were colloidally stable and exhibited particle sizes and zeta potentials similar to those of the control composition (4A). Polishing compositions 4L-4M (containing sulfur-containing anionic surfactants with carbon chain lengths of 14 or more) were colloidally unstable.

[0085] Example 5 The colloidal stability of 21 tungsten polishing compositions (Compositions 5AA-5GC) was evaluated. Each composition contained 1.1 weight percent (11,000 ppm) of one of three colloidal silicas with a permanent positive charge. Type A colloidal silica had an average particle size of approximately 100 nm and contained a permanent positive charge imparted by surface treatment with an aminosilane, as described in Example 7 of U.S. Pat. No. 9,382,450. Type B colloidal silica had an average particle size of approximately 50 nm and contained an internal aminosilane, as described in Example 13 of U.S. Pat. No. 9,422,456. Type C colloidal silica had an average particle size of approximately 120 nm and contained a permanent positive charge imparted by surface treatment with an aminosilane, as described in Example 7 of U.S. Pat. No. 9,382,450.

[0086] Each composition further contained 100 ppm by weight of ferric nitrate nonahydrate (14 ppm Fe), 300 ppm by weight of malonic acid, 400 ppm by weight of L-glutamic acid, and 15 ppm by weight of Kathon LX biocide. The pH of each composition was adjusted to 2.5. Each composition also contained 100 ppm by weight of a sulfur-containing anionic surfactant listed in Table 5A. The carbon chain length of each anionic surfactant is also listed in Table 5A. TIFF2025531390000013.tif120170

[0087]

[0087] The average particle size and zeta potential of the colloidal silica in each polishing composition was measured using a Zetasizer from Malvern, and the test results are shown in Figure 5B. TIFF2025531390000014.tif120170

[0088]

[0088] As can be seen from the results shown in Table 5B, polishing compositions 5AA-5GC (containing sulfur-containing anionic surfactants with carbon chain lengths of 12 or less) were colloidally stable and exhibited particle sizes and zeta potentials similar to those of the control compositions (5AA-5AC) across a range of colloidal silica particle sizes (approximately 50 nm to approximately 120 nm).

[0089] Example 6 The colloidal stability of nine tungsten polishing compositions (Compositions 6A-6I) was evaluated. Each composition contained 1.1 weight percent of the colloidal silica described in Example 1 above. Each composition further contained 100 weight ppm ferric nitrate nonahydrate (14 ppm Fe), 300 weight ppm malonic acid, 400 weight ppm L-glutamic acid, and 15 weight ppm Kathon LX biocide. The pH of each composition was adjusted to 2.5. Each composition further contained a sulfur-containing anionic surfactant in the amount (ppm) listed in Table 6A. The carbon chain length of each anionic surfactant is also listed in Table 6A. TIFF2025531390000015.tif55170

[0090]

[0090] The average particle size and zeta potential of the colloidal silica in each polishing composition was measured using a Zetasizer from Malvern. The test results are listed in Table 6B. TIFF2025531390000016.tif55170

[0091] As can be seen from the results shown in Table 6B, Polishing Compositions 6B-6I (containing sulfur-containing anionic surfactants with carbon chain lengths of 4-10) were colloidally stable and exhibited particle sizes and zeta potentials similar to those of the control composition (6A). The particle size of Polishing Composition 6I (containing 1000 ppm sodium decyl sulfate and 1.1 weight percent colloidal silica) increased significantly from 120 nm to 133 nm, yet the composition remained colloidally stable.

[0092]

[0092] It will be understood that the recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each individual value within that range, unless otherwise stated herein, and that each individual value is incorporated into the specification as if it were individually set forth herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any examples or exemplary language (e.g., "such as") provided herein is solely for the purpose of improving the understanding of the invention and does not impose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0093]

[0093] This specification describes preferred embodiments of the invention, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments will become apparent to those skilled in the art upon reading the foregoing description. The inventors expect those skilled in the art to adopt such variations as necessary, and it is intended that the invention be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, this invention includes any combination of the above-described elements in all possible variations thereof unless otherwise indicated herein or clearly contradicted by context.

Claims

1. 1. A chemical-mechanical polishing composition comprising: A liquid carrier; cationic abrasive particles dispersed in a liquid carrier; an iron-containing accelerator; a tungsten etch inhibitor; and Sulfur-containing anionic surfactants and Including, having a pH of less than about 5 composition.

2. The composition of claim 1 , wherein the cationic abrasive particles comprise colloidal silica.

3. 3. The composition of claim 2, wherein the colloidal silica particles comprise an internal aminosilane compound or an aminosilane compound attached to the outer surface of the particles.

4. 3. The composition of claim 2, wherein the colloidal silica has a zeta potential greater than about 20 mV.

5. 3. The composition of claim 2, comprising less than about 1 weight percent colloidal silica particles at the point of use.

6. 10. The composition of claim 1, wherein the iron-containing accelerator comprises a soluble iron-containing catalyst, and the composition further comprises a stabilizer bound to the soluble iron-containing catalyst, the stabilizer being selected from the group consisting of phosphoric acid, phthalic acid, citric acid, adipic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, maleic acid, glutaconic acid, muconic acid, ethylenediaminetetraacetic acid, propylenediaminetetraacetic acid, and mixtures thereof.

7. 10. The composition of claim 1, wherein the tungsten etch inhibitor is positively charged at the pH of the composition.

8. 10. The composition of claim 1, wherein the tungsten etch inhibitor comprises an amino acid selected from the group consisting of glycine, glutamic acid, arginine, aspartic acid, lysine, histidine, and mixtures thereof, or a polyamino acid selected from the group consisting of polylysine, polyarginine, polyhistidine, and mixtures thereof.

9. The sulfur-containing anionic surfactant is [In the formula, represents an alkyl or alkane group, a branched alkyl or alkane group, or a cyclic group having less than 14 carbon atoms.

10. The composition of claim 1, wherein 10. The composition of claim 9, wherein the alkyl or alkane group has a longest linear carbon chain containing from about 4 carbon atoms to about 12 carbon atoms, or the alkyl or alkane group is a branched alkyl or alkane group.

11. 11. The composition of claim 10, wherein the longest linear carbon chain contains from about 6 carbon atoms to about 10 carbon atoms.

12. 2. The composition of claim 1, wherein the sulfur-containing anionic surfactant is selected from the group consisting of butane sulfonate, butyl sulfate, pentane sulfonate, pentyl sulfate, hexane sulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, dodecane sulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

13. 2. The composition of claim 1, wherein the sulfur-containing anionic surfactant is selected from the group consisting of hexane sulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

14. 10. The composition of claim 1, comprising from about 10 ppm to about 1000 ppm by weight of the sulfur-containing anionic surfactant at the point of use.

15. 10. The composition of claim 1, wherein the tungsten etch inhibitor comprises from about 1 ppm to about 100 ppm by weight of polylysine at the point of use.

16. 10. The composition of claim 1, wherein the tungsten etch inhibitor comprises from about 50 ppm to about 5000 ppm by weight of glutamic acid, glycine, lysine, or a mixture thereof at the point of use.

17. 10. The composition of claim 1 having a pH in the range of about 2 to about 4.

18. The composition of claim 1 further comprising a hydrogen peroxide oxidizing agent.

19. the sulfur-containing anionic surfactant is selected from the group consisting of butane sulfonate, butyl sulfate, pentane sulfonate, pentyl sulfate, hexane sulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octane sulfonate, octyl sulfate, decane sulfonate, decyl sulfate, dodecane sulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof; the composition comprises from about 10 ppm to about 1000 ppm by weight of a sulfur-containing anionic surfactant; 10. The composition of claim 1, wherein the tungsten etch inhibitor comprises from about 1 ppm to about 100 ppm by weight of polylysine at the point of use, or from about 50 ppm to about 5000 ppm by weight of glutamic acid, glycine, lysine, or a mixture thereof at the point of use.

20. 1. A method of chemical mechanical polishing a patterned tungsten-containing substrate, comprising: (a) a substrate; A liquid carrier; cationic abrasive particles dispersed in a liquid carrier; an iron-containing accelerator; a tungsten etch inhibitor; and Sulfur-containing anionic surfactants and Including, having a pH of less than about 5 contacting the polishing composition with a polishing composition; (b) moving the polishing composition relative to the substrate; (c) polishing the substrate to remove a portion of the at least one tungsten layer from the substrate, thereby polishing the substrate; A method comprising:

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