Tungsten CMP composition containing sulfur-containing anionic surfactant

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 in the art. Polishing compositions (also referred to as polishing slurries, CMP slurries, and CMP compositions) for polishing various metal layers (such as tungsten) and non-metal layers (such as silicon oxide) on a semiconductor substrate can comprise abrasive particles suspended in an aqueous solution, and various chemical additives such as oxidizing agents, chelating agents, catalysts, topography control agents, and buffering agents. Background Art

[0002]

[0002] In conventional CMP operations, a substrate (wafer) to be polished is mounted on a carrier, the carrier is mounted on a carrier assembly and positioned to contact a polishing pad in a CMP polishing tool. The carrier assembly provides controlled pressure to the substrate against the polishing pad. The substrate and the polishing pad move relative to each other by an external driving force. The relative movement between the substrate and the polishing pad grinds 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 movement between the pad and the substrate can be further promoted by the chemical activity of the polishing composition and / or the mechanical activity of the abrasive suspended in the polishing composition.

[0003]

[0003] As is well known, continuous miniaturization is strongly demanded in the semiconductor industry. This miniaturization reduces device feature sizes and makes planarization requirements more stringent for commercial CMP processes. There is a need in the industry for CMP compositions (e.g., tungsten CMP compositions) that improve planarity without sacrificing throughput or increasing cost. Summary of the Invention

[0004]

[0004] A chemical mechanical polishing composition for use in tungsten CMP operations is disclosed. The composition comprises, essentially comprises, or includes a liquid carrier, cationic polishing particles dispersed in the liquid carrier, an iron-containing accelerator, a tungsten etching inhibitor, and a sulfur-containing anionic surfactant. The composition has a pH of less than about 5. [Modes for carrying out the invention]

[0005]

[0005] Chemical mechanical polishing compositions for polishing tungsten are disclosed. In one embodiment, the composition comprises a liquid carrier and cationic polishing particles (such as cationic colloidal silica particles) dispersed therein. The polishing composition may further comprise an iron-containing accelerator, a tungsten etching inhibitor, and a sulfur-containing anionic surfactant. A method for using the disclosed composition to polish a tungsten-containing substrate is also disclosed.

[0006]

[0006] It will be understood that the disclosed CMP composition can be advantageously used in bulk tungsten removal CMP operations (sometimes referred to in the art as first-step tungsten CMP operations). Bulk removal operations typically require a high tungsten removal rate and a low tungsten etching rate. The disclosed CMP composition can also be advantageously used in single-step tungsten CMP operations. The disclosed polishing composition has been found to advantageously provide a high tungsten removal rate, as well as improved flatness and reduced patterned oxide loss. Thus, this composition can result in improved topographic control, such as improved erosion and dishing on device wafers.

[0007]

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

[0008]

[0008] The abrasive particles can include substantially any suitable cationic abrasive particles, for example, alpha-alumina particles, silica particles, and / or aluminum-doped silica particles. Cationic means that the abrasive particles are positively charged at the pH of the abrasive composition. In preferred embodiments, the abrasive particles may 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 a wet process rather than by the pyrolysis or flame hydrolysis methods used in the production of fumed silica. It will be understood that colloidal silica particles and fumed silica particles are generally structurally different particles. Colloidal silica may be precipitated silica or condensation-polymerized silica and can be prepared using any method known to those skilled in the art, such as the sol-gel method or silicate ion exchange. Condensation-polymerized silica particles are often prepared by condensing Si(OH)4 to form substantially spherical particles. Preferred embodiments include colloidal silica particles.

[0009]

[0009] As is well known to those skilled in the art, colloidal silica particles may be aggregated or unaggregated. Unaggregated particles are individually independent particles that are spherical or nearly spherical in shape, but may also have other shapes (usually such as elliptical, square, or rectangular cross-sections). Aggregated particles are particles in which multiple individual particles come together and bind to form aggregates, generally of an irregular shape. Aggregated colloidal silica particles are disclosed, for example, in U.S. Patent No. 9,309,442 by the same applicant.

[0010]

[0010] The charge on silica particles is commonly referred to in the art as the zeta potential (or electrodynamic potential). As is 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). The zeta potential can be obtained using commercially available measuring instruments such as the Zetasizer from Malvern Instruments, the ZetaPlus Zeta Potential Analyzer from Brookhaven Instruments, and / or the electroacoustic spectrometer from Dispersion Technologies, Inc.

[0011]

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

[0012]

[0012] The disclosed embodiments are not limited in this respect, but 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 by, for example, flushing, dilution, or filtration. The permanent positive charge may arise, for example, from the covalent bonding of a cationic compound with colloidal silica (e.g., the outer surface of the particles). A permanent positive charge is in contrast to a reversible positive charge that may arise, for example, as a result of electrostatic interactions between a cationic compound and 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-step ultrafiltration test, which is further described in detail in U.S. Patent No. 9,238,754 of the same applicant.

[0013]

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

[0014]

[0014] Alternatively, cationic silica particles may be imparted a non-permanent positive charge, for example, by contact with a cation-containing component (i.e., a positively charged species) in a 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 may have substantially any suitable particle size. The particle size of particles suspended in a liquid carrier is defined in the industry by various means. For example, particle size can be defined as the diameter of the smallest sphere surrounding the particle and can be measured using, for example, a CPS disk 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). Therefore, colloidal silica particles may have an average particle size in the range of approximately 5 nm to approximately 200 nm (for example, approximately 20 nm to approximately 180 nm, approximately 40 nm to approximately 160 nm, or approximately 50 nm to approximately 150 nm).

[0016]

[0016] The abrasive composition may contain substantially any suitable amount of the above-mentioned anionic particles, but it is preferable to contain 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, thereby potentially reducing costs further. For example, the abrasive composition may contain about 0.01% by weight or more (e.g., about 0.02% by weight or more, about 0.03% by weight or more, or about 0.05% by weight or more) of abrasive particles at the time of use. The amount of abrasive particles in the abrasive composition may be about 10% by weight or less (e.g., about 2% by weight or less, about 1% by weight or less, about 0.5% by weight or less, about 0.3% by weight or less, or about 0.2% by weight or less) at the time of use. Therefore, it will be understood that the amount of abrasive particles at the time of use may be within a range bounded by any two of the aforementioned endpoints, for example, within a range of about 0.01% by weight to about 10% by weight (for example, about 0.01% by weight to about 2% by weight, about 0.02% by weight to about 1% by weight, about 0.02% by weight to about 0.5% by weight, or about 0.03% by weight to about 0.3% by weight).

[0017]

[0017] The disclosed abrasive compositions are generally acidic, with a pH 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). It will be understood that the pH of the abrasive composition may be limited by any of the aforementioned endpoints, for example, within the 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 transport concerns, a pH greater than about 2 is preferred.

[0018]

[0018] The pH of the abrasive composition can be achieved and / or maintained by any suitable means. The abrasive composition may contain substantially 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 may include phosphates, sulfates, acetates, malonates, oxalates, borates, ammonium salts, etc.

[0019]

[0019] The disclosed compositions further comprise an iron-containing tungsten polishing accelerator and a corresponding stabilizer. The iron-containing accelerators used herein are iron-containing compounds that increase the rate of tungsten removal during tungsten CMP operations. For example, the iron-containing accelerator may include soluble iron-containing catalysts such as those disclosed in U.S. Patents 5,958,288 and 5,980,775. Such iron-containing catalysts may be soluble in a liquid carrier and may include, for example, ferric (iron III) or ferrous (iron) compounds such as iron halides including iron nitrate, iron sulfate, fluoride, chloride, bromide, and iodide, as well as organoiron compounds such as perchlorates, perbromates and periodates, and iron acetate, carboxylic acids, acetylacetones, citrates, glucons, malons, oxalates, phthalates, succinates, and mixtures thereof.

[0020]

[0020] The iron-containing accelerator may also include an iron-containing activator (e.g., a free radical generating compound) or an iron-containing catalyst bonded (e.g., coated or bonded) to the surface of colloidal silica particles, such as those disclosed in U.S. Patents No. 7,029,508 and No. 7,077,880. For example, the iron-containing accelerator can bond to silanol groups on the surface of colloidal surface particles.

[0021]

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

[0022]

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

[0023]

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

[0024]

[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 composition 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 enhancer. As used herein, the term "equivalent per iron-containing enhancer" means one molecule of stabilizer per iron ion in the composition. For example, 2 equivalents per iron-containing enhancer means 2 molecules of stabilizer per catalyst ion.

[0025]

[0025] The polishing composition may optionally further contain an oxidizing agent. The oxidizing agent can be added to the polishing composition during the slurry manufacturing process or immediately before the CMP operation (for example, in a tank or slurry distribution system in a semiconductor manufacturing facility common in the industry). Preferred oxidizing agents include inorganic or organic per compounds. Per compounds as defined herein are compounds containing at least one peroxy group (-O--O-) or compounds containing an element in the highest oxidation state. Examples of compounds containing at least one peroxy group are, but are not limited to, hydrogen peroxide and its adducts such as urea peroxide and parkerbonate, organic peroxides such as benzoyl peroxide, peracetic acid, and di-t-butyl peroxide, and monopersulfates (SO5 = ), dispersulfate (S2O8 =), and sodium peroxide. Examples of compounds containing an element in the highest oxidation state include, but are not limited to, periodic acid, periodate, perbromic acid, perbromate, perchloric acid, perchlorate, perboric acid, perborate and permanganate. The most preferred oxidizing agent is hydrogen peroxide.

[0026]

[0026] The oxidizing agent may be present in the polishing composition in an amount ranging, for example, from about 0.1 wt% to about 20 wt% at the point of use. For example, in embodiments where a hydrogen peroxide oxidizing agent and a soluble iron-containing accelerator are used, the oxidizing agent may be present in the polishing composition in an amount ranging from about 0.1 wt% to about 10 wt% at the point of use (e.g., from about 0.5 wt% to about 5 wt%, or from about 1 wt% 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 suppress the conversion of solid tungsten to soluble tungsten compounds, while at the same time enabling effective removal of solid tungsten by CMP operation. The polishing composition can include substantially any suitable inhibitor, for example, the inhibitor compounds disclosed in commonly assigned U.S. Patent Nos. 9,238,754; 9,303,188; and 9,303,189.

[0028]

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

[0029]

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

[0030]

[0030] In certain embodiments, the tungsten etching inhibitor may include a polyamino acid compound. Suitable polyamino acid compounds may include substantially 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, polylysine may be primarily ε-poly-L-lysine.

[0031]

[0031] The tungsten etching inhibitor may further (or alternatively) contain a derivatized polyamino acid (i.e., a cationic polymer containing derivatized amino acid monomer units). For example, the derivatized polyamino acid may include derivatized polyarginine, derivatized polyornithine, derivatized polyhistidine, and derivatized polylysine. A CMP composition containing a derivatized polyamino acid compound is disclosed in U.S. Patent Publication No. 2021 / 0206920.

[0032]

[0032] In certain advantageous embodiments, the disclosed polishing compositions include amino acid tungsten etching inhibitors such as glycine, glutamic acid, lysine, histidine, arginine, aspartic acid, or mixtures thereof, or polyamino acid tungsten etching inhibitors such as polyhistidine, polylysine, polyarginine, or mixtures thereof. Of course, it will be understood that the tungsten etching inhibitors can be used in any available form (for example, in the form of a conjugate acid or conjugate base and salt, which can be used instead of or in addition to the form of an acid). The term “acid” as used in describing useful compounds in this context means the acid itself and any form of acid that can modify titratable functional groups by adjusting the pH. Such forms include its conjugate base or acid and other salts thereof. For example, the term “glutamic acid” means not only the amino acid form but also the conjugate acid formed by protonating the amine functional group. Similarly, “polylysine” means polylysine polyamino acids and their conjugate acids formed by protonating the amine functional group.

[0033]

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

[0034]

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

[0035]

[0035] In polishing compositions 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 of the polyamino acid tungsten etching inhibitor at the time of use (for example, about 2 ppm to about 50 ppm, or about 3 ppm to about 30 ppm). In polishing compositions 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 (for example, 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. Anionic surfactant means that the compound contains a functional group that is negatively charged in a desired pH range (e.g., the pH of the composition). Sulfur-containing means that the anionic surfactant contains at least one sulfur atom, for example, a sulfate or sulfonate functional group in a preferred embodiment. In exemplary embodiments, the sulfur-containing anionic surfactant may be represented by one of the following formulas: TIFF0007920448000001.tif7170 represents an alkyl group, an alkane group, a branched alkyl group, an alkane group, or a cyclic group with fewer than 14 carbon atoms. In preferred embodiments, TIFF0007920448000002.tif4170 represents an alkyl or alkane group, or a branched alkyl or alkane group, whose longest straight carbon chain contains approximately 4 to 12 carbon atoms, more preferably approximately 6 to 10 carbon atoms.

[0037]

[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, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, dodecanesulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof. Naturally, it will be understood that, where applicable, the above anionic surfactants can be provided as hydrophilic acids, or as conjugate base salts, or as mixtures thereof containing any suitable positively charged counterions such as sodium, potassium, or ammonium cations.

[0038]

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

[0039]

[0039] The disclosed abrasive compositions may include substantially any additional chemical additives. For example, the disclosed compositions may include additional tungsten etching inhibitors and terrain control agents, dispersants, and biocides. Such additional additives are purely optional. The disclosed embodiments are not limited in that respect 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, isothiazolinone biocides known to those skilled in the art.

[0040]

[0040] Abrasive compositions can be prepared using any suitable technique, many of which are known to those skilled in the art. Abrasive compositions can be prepared in batch or continuous processes. Generally, abrasive compositions can be prepared by combining their components in any order. As used herein, the term “components” includes individual components (e.g., colloidal silica, iron content enhancers, amine compounds, etc.).

[0041]

[0041] For example, polishing composition components (such as iron-containing accelerators, stabilizers, tungsten etching 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 proper mixing. Such mixing / mixing techniques are well known to those skilled in the art. If an oxidizing agent is present, it can be added at any time during the preparation of the polishing composition. For example, the polishing composition can be prepared immediately before 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) 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 the polishing pad) during the CMP operation.

[0042]

[0042] The polishing composition may be advantageously supplied as a one-package system containing colloidal silica having the physical properties described above and any other optional components. The oxidizing agent may preferably 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 the other two or more containers of the components of the polishing composition are within the knowledge of those skilled in the art.

[0043]

[0043] The polishing compositions of the present invention may also be provided as concentrates intended to be diluted with an appropriate amount of water before use. In such embodiments, the polishing composition concentrate may contain an abrasive (such as silica), an iron content accelerator, a stabilizer, a tungsten etching inhibitor, and an optional biocide, in amounts such that when the concentrate is diluted with an appropriate amount of water and an optional oxidizing agent, if an appropriate amount is not already present, each component of the polishing composition may be present in the polishing composition in amounts within the appropriate range listed above for each component. For example, colloidal silica and other optional components may each be present in the polishing composition in amounts about twice (e.g., about three times, about four times, about five times, or even about ten times) greater than the use-time concentrations listed above for each component, so that when the concentrate is diluted with an equal amount of water (e.g., 2 equal parts of water, 3 equal parts of water, 4 equal parts of water, or 9 equal parts of water, respectively), each component will be present in the polishing composition in amounts within the above range for each component, along with an appropriate amount of oxidizing agent. Furthermore, as will be understood by those skilled in the art, the concentrate may contain 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]

[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 may be deposited on one or more barrier layers, for example, titanium and / or titanium nitride (TiN). The dielectric layer may be a metal oxide, for example, 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-dielectric-constant or low-dielectric-constant insulating layer.

[0045]

[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 motion, linear motion, or circular motion, a polishing pad that is in contact with the platen and moves with the platen during movement, and a carrier that is in contact with the surface of the polishing pad and holds a substrate to be polished by moving relative to the surface of the polishing pad. Polishing of the substrate is performed 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 the substrate by polishing at least a portion of the substrate (such as tungsten, titanium, titanium nitride, and / or dielectric materials as described herein).

[0046]

[0046] In certain preferred embodiments, the disclosed polishing compositions can improve flatness with minimal or no throughput loss. Examples of 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 of patterned wafers.

[0047]

[0047] The substrate can be planarized or polished using a chemical mechanical polishing composition with any suitable polishing pad (e.g., polishing surface). Suitable polishing pads include, for example, woven and nonwoven polishing pads. Furthermore, suitable polishing pads can include any suitable polymer having various densities, hardness, thickness, compressibility, rebound capacity under compression, and compressive modulus. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, co-molded products thereof, and mixtures thereof.

[0048]

[0048] It will be understood that this disclosure includes a number of embodiments. These embodiments include, but are not limited to, the following embodiments.

[0049]

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

[0050]

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

[0051]

[0051] The third embodiment includes the second embodiment, wherein the colloidal silica particles include an internal aminosilane compound or an aminosilane compound bonded to the external surface of the particles.

[0052]

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

[0053]

[0053] The fifth embodiment may include any one of the second to fourth embodiments, which contains less than about 1 weight percent of colloidal silica particles at the time of use.

[0054]

[0054] The sixth embodiment comprises any one of the first to fifth embodiments, wherein the iron content enhancer comprises a soluble iron-containing catalyst, and the composition further comprises a stabilizer bonded 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] The seventh embodiment comprises any one of the first to sixth embodiments, wherein the tungsten etching inhibitor is positively charged at the pH of the composition.

[0056]

[0056] The eighth embodiment comprises any one of the first to seventh embodiments, wherein the tungsten etching 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.

[0057]

[0057] The ninth embodiment comprises any one of the first to eighth embodiments, wherein the sulfur-containing anionic surfactant is of the formula TIFF0007920448000003.tif7170 represents an alkyl group, a branched alkyl group, or a cyclic group having fewer than 14 carbon atoms.

[0058]

[0058] The tenth embodiment may include the ninth embodiment, in which case, TIFF0007920448000004.tif4170 represents an alkyl group or branched alkyl group having the longest straight carbon chain containing approximately 4 to 12 carbon atoms.

[0059]

[0059] The 11th embodiment includes the 10th embodiment, wherein the longest linear carbon chain contains about 6 to about 10 carbon atoms.

[0060]

[0060] The twelfth embodiment comprises any one of the first to eleventh embodiments, wherein the sulfur-containing anionic surfactant is selected from the group consisting of butanesulfonate, butyl sulfate, pentyl sulfonate, pentyl sulfate, hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, dodecanesulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

[0061]

[0061] The 13th embodiment comprises any one of the 1st to 12th embodiments, wherein the sulfur-containing anionic surfactant is selected from the group consisting of hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

[0062]

[0062] The 14th embodiment includes any one of the 1st to 13th embodiments, wherein the weight ratio of the sulfur-containing anionic surfactant at the time of use is approximately 10 ppm to approximately 1000 ppm.

[0063]

[0063] The 15th embodiment may include any one of the 1st to 14th embodiments, wherein the tungsten etching inhibitor contains about 1 ppm by weight to about 100 ppm by weight of polylysine at the time of use.

[0064]

[0064] The 16th embodiment may include any one of the 1st to 14th embodiments, wherein the tungsten etching inhibitor comprises glutamic acid, glycine, lysine, or a mixture thereof in an amount of about 50 ppm by weight to about 5000 ppm by weight at the time of use.

[0065]

[0065] The 17th embodiment comprises any one of the 1st to 16th embodiments and has a pH in the range of about 2 to about 4.

[0066]

[0066] The 18th embodiment comprises any one of the 1st to 17th embodiments and further comprises a hydrogen peroxide oxidizing agent.

[0067]

[0067] The 19th embodiment may include any one of the 1st to 18th embodiments, wherein the sulfur-containing anionic surfactant is selected from the group consisting of butanesulfonate, butyl sulfate, pentyl sulfonate, pentyl sulfate, hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, dodecanesulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof, and the composition contains about 10 ppm by weight to about 1000 ppm by weight of the sulfur-containing anionic surfactant, and the tungsten etching inhibitor contains about 1 ppm by weight to about 100 ppm by weight of polylysine at the time of use, or about 50 ppm by weight to about 5000 ppm by weight of glutamic acid, glycine, lysine, or mixtures thereof at the time of use.

[0068]

[0068] In the 20th embodiment, a method for chemically and mechanically polishing a patterned tungsten-containing substrate is to (a) bring the substrate into contact with one of the polishing compositions described in the first to 19th embodiments, (b) move the polishing composition with respect to the substrate, and (c) polish the substrate so as to remove a portion of at least one tungsten layer from the substrate, thereby polishing the substrate. Includes.

[0069]

[0069] The following embodiments further illustrate the present invention, but of course, should not be interpreted as limiting its scope in any sense.

[0070] Example 1

[0070] Five tungsten polishing compositions (compositions 1A to 1E) were prepared and evaluated. Each composition contained 0.1 wt percent (1000 ppm by weight) of colloidal silica with an average particle size of approximately 120 nm and containing a permanent positive charge imparted by surface treatment with aminosilane as described in Example 7 of U.S. Patent No. 9,382,450. Each composition further contained 200 wt ppm of ferric nitrate nonahydrate (27 ppm of Fe), 300 wt ppm of malonic acid, 2 wt ppm of Kathon LX biocide, and 1 wt percent of hydrogen peroxide. The pH of each composition was adjusted to 2.7 using potassium hydroxide. Polishing composition 1A further contained 10 wt ppm of 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 to 1E are further summarized in Table 1A. TIFF0007920448000005.tif62170

[0071]

[0071] The polishing performance of the blanket and patterned wafer 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) with a Reflexion® CMP tool (available from Applied Materials) using Pad 5C from U.S. Patent Publication No. 2021 / 0008687 of the same applicant. 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), but was then reduced to 1.2 psi during a 25-second overpolish. Pad conditioning was applied ex-situ for 24 seconds with a downforce of 6 pounds using a 3M A122 conditioning disc.

[0072]

[0072] The polishing performance of the blanket and patterned wafer is summarized in Table 1B. TIFF0007920448000006.tif40170

[0073]

[0073] As is clear from the results shown in Table 1B, polishing compositions 1B and 1E (containing Starquat and arginine supplement additives) showed higher erosion than the control compositions (1A and 1D). Polishing composition 1E showed even greater dishing. Polishing composition 1D (containing the sodium ethylhexyl sulfate additive of the present invention) showed 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). Therefore, it is clear that the polishing compositions containing the sulfur-containing anionic surfactant of the present invention (sodium ethylhexyl sulfate in this example) showed improved overall flatness.

[0074] Example 2

[0074] Three tungsten polishing compositions (compositions 2A to 2C) were prepared and evaluated. Each composition contained 0.2 wt percent (2000 ppm by weight) of the colloidal silica described in Example 1 above. Each composition further contained 200 wt ppm of ferric nitrate nonahydrate (27 ppm Fe), 400 wt ppm of malonic acid, 10 wt ppm of ε-poly-L-lysine, 2 wt ppm of Kathon LX biocide, and 3 wt percent of hydrogen peroxide. The pH of each composition was adjusted to 2.7 using potassium hydroxide. Polishing composition 2B further contained 100 wt ppm of sodium ethylhexyl sulfate. Polishing composition 2C further contained 100 ppm by weight of L-cysteic acid monohydrate. Polishing compositions 2A to 2C are further summarized in Table 2A. TIFF0007920448000007.tif42170

[0075]

[0075] The polishing performance of patterned wafers was evaluated by polishing a Silyb 2kÅ MIT 754 tungsten patterned wafer (available from Silyb Wafer Services) with a Reflexion® CMP tool (available from Applied Materials) and an E6088 polishing pad (available from CMC 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 the endpoint and then over-polished for 15 seconds. Endpoint time (time until tungsten and barrier film are removed) and flag time (time until tungsten film is removed) were recorded. Pad conditioning was applied ex-situ for 24 seconds with a downforce of 6 pounds using a 3M A122 conditioning disc.

[0076]

[0076] The polishing performance of the patterned wafers is summarized in Table 2B. TIFF0007920448000008.tif35170

[0077]

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

[0078] Example 3

[0078] Three tungsten polishing compositions (compositions 3A to 3C) were prepared and evaluated. Each composition contained 0.2 wt percent (2000 ppm by weight) of the colloidal silica described in Example 1 above. Each composition further contained 200 wt ppm of ferric nitrate nonahydrate (27 ppm Fe), 400 wt ppm of malonic acid, 10 wt ppm of ε-poly-L-lysine, 2 wt ppm of Kathon LX biocide, and 3 wt percent of hydrogen peroxide. The pH of each composition was adjusted to 2.7 using potassium hydroxide. Polishing composition 3B further contained 100 wt ppm of sodium ethylhexyl sulfate. Polishing composition 3C further contained 100 wt ppm of sodium decyl sulfate. Polishing compositions 3A to 3C are further summarized in Table 2A. TIFF0007920448000009.tif42170

[0079]

[0079] The polishing performance of patterned wafers was evaluated by polishing a Silyb 2kÅ MIT 754 tungsten patterned wafer (available from Silyb Wafer Services) with a Mirra® CMP tool (available from Applied Materials) and an E6088 polishing pad (available from CMC Materials). The polishing process was performed with 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 then over-polished for 15 seconds. Pad conditioning was applied ex-situ for 24 seconds with a downforce of 6 pounds using a 3M A122 conditioning disc. The TEOS blanket wafer was polished for 60 seconds.

[0080]

[0080] The polishing performance of the patterned wafers is summarized in Table 2B. TIFF0007920448000010.tif35170

[0081]

[0081] As is clear from the results shown in Table 3B, polishing compositions 3B and 3C (containing ethylhexyl sulfate and decyl sulfate as auxiliary additives) showed less erosion than the control composition (2A). Furthermore, polishing compositions 3B and 3C showed similar (or slightly reduced) patterned tungsten removal rates and reduced patterned oxide (TEOS) removal rates (indicating reduced patterned oxide loss). Therefore, it is clear that the polishing compositions containing the sulfur-containing anionic surfactants of the present invention (ethylhexyl sulfate and sodium decyl sulfate in this example) showed improved overall flatness and comparable throughput to the control composition (3A).

[0082] Example 4

[0082] The colloidal stability of 15 (17 if 12C) tungsten polishing compositions (compositions 4A to 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 the amount (ppm by weight) of a sulfur-containing anionic surfactant listed in Table 4A. The carbon chain length of each anionic surfactant is also listed in Table 4A. TIFF0007920448000011.tif80170

[0083]

[0083] The average particle size and zeta potential of colloidal silica in each polishing composition were measured using a Zetasizer from Malvern. The test results are shown in Figure 4B. TIFF0007920448000012.tif80170

[0084]

[0084] As is clear from the results shown in Table 4B, polishing compositions 4A to 4K (containing sulfur-containing anionic surfactants with a carbon chain length of 12 or less) were colloidally stable and exhibited the same particle size and zeta potential as the control composition (4A). Polishing compositions 4L to 4M (containing sulfur-containing anionic surfactants with a carbon chain length of 14 or more) were colloidally unstable.

[0085] Example 5

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

[0086]

[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 further contained 100 ppm by weight of a sulfur-containing anionic surfactant as described in Table 5A. The carbon chain lengths of each anionic surfactant are also described in Table 5A. TIFF0007920448000013.tif120170

[0087]

[0087] The average particle size and zeta potential of colloidal silica in each polishing composition were measured using a Zetasizer from Malvern. The test results are shown in Figure 5B. TIFF0007920448000014.tif120170

[0088]

[0088] As is clear from the results shown in Table 5B, the polishing compositions 5AA to 5GC (containing sulfur-containing anionic surfactants having a carbon chain length of 12 or less) were colloidally stable and exhibited similar particle size and zeta potential to the control compositions (5AA to 5AC) over a range of colloidal silica particle sizes (approximately 50 nm to approximately 120 nm).

[0089] Example 6

[0089] The colloidal stability of the tungsten polishing compositions (compositions 6A to 6I) was evaluated. Each composition contained 1.1% 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 the amount (ppm by weight) of a sulfur-containing anionic surfactant listed in Table 6A. The carbon chain length of each anionic surfactant is also listed in Table 6A. TIFF0007920448000015.tif55170

[0090]

[0090] The average particle size and zeta potential of colloidal silica in each polishing composition were measured using a Zetasizer from Malvern. The test results are listed in Table 6B. TIFF0007920448000016.tif55170

[0091]

[0091] As is clear from the results shown in Table 6B, polishing compositions 6B to 6I (containing sulfur-containing anionic surfactants with carbon chain lengths of 4 to 10) were colloidally stable and exhibited similar particle size and zeta potential to the control composition (6A). The particle size of polishing composition 6I (containing 1000 ppm decyl sulfate sodium and 1.1 wt percent colloidal silica) increased significantly to 120 nm to 133 nm, but the composition remained colloidally stable.

[0092]

[0092] Unless otherwise stated herein, the descriptions of value ranges are merely intended to serve as a simplified way of individually referring to each individual value within that range, and it will be understood that each individual value is invoked in the specification as if it were individually stated herein. All methods described herein may be performed in any suitable order unless otherwise indicated herein or unless it is clearly inconsistent with the context. Any use of any examples or illustrative expressions provided herein (e.g., "such as") is solely for the purpose of better understanding the invention and does not impose any limitation on the scope of the invention unless otherwise requested. Nothing in this specification should be construed as indicating that any element not described in the claims is essential for the practice of the invention.

[0093]

[0093] Preferred embodiments of the Invention will be described herein, including the best mode known to the inventors for carrying out the Invention. Variations of these preferred embodiments will be apparent to those skilled in the art by reading the foregoing description. The inventors expect that those skilled in the art will adopt such variations as appropriate, and the Invention is intended to be carried out in ways other than those specifically described herein. Accordingly, the Invention includes all modifications and equivalents of the subject matter described in the claims appended herein, as permitted by applicable law. Furthermore, unless otherwise indicated herein, or unless clearly inconsistent with the context, any combination of the elements described above in any possible variation is incorporated into the Invention.

Claims

1. A chemical mechanical abrasive composition, Liquid carriers, Cationic abrasive particles dispersed in a liquid carrier, Iron content enhancer, Tungsten etching inhibitor, Sulfur-containing anionic surfactant and Includes, Having a pH of less than 5, A composition comprising cationic abrasive particles and colloidal silica particles.

2. The composition according to claim 1, wherein colloidal silica particles contain an aminosilane compound internally or an aminosilane compound bonded to the external surface of the particles.

3. The composition according to claim 1, wherein the colloidal silica particles have a zeta potential greater than 20 mV.

4. The composition according to claim 1, comprising less than 1% by weight of colloidal silica particles at the time of use.

5. The composition according to claim 1, wherein the iron-containing accelerator comprises a soluble iron-containing catalyst, and the composition further comprises a stabilizer bonded 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.

6. The composition according to claim 1, wherein the tungsten etching inhibitor is positively charged at the pH of the composition.

7. The composition according to claim 1, wherein the tungsten etching 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.

8. Sulfur-containing anionic surfactants [In the formula, [Represents an alkyl group or alkane group, a branched alkyl group or alkane group, or a cyclic group having fewer than 14 carbon atoms.] The composition according to claim 1, having the following characteristics.

9. The composition according to claim 8, which represents an alkyl or alkane group having the longest straight carbon chain containing 4 to 12 carbon atoms, or a branched alkyl or branched alkane group.

10. The composition according to claim 9, wherein the longest straight carbon chain contains 6 to 10 carbon atoms.

11. The composition according to claim 1, wherein the sulfur-containing anionic surfactant is selected from the group consisting of butanesulfonate, butyl sulfate, pentanesulfonate, pentyl sulfate, hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, dodecanesulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

12. The composition according to claim 1, wherein the sulfur-containing anionic surfactant is selected from the group consisting of hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof.

13. The composition according to claim 1, comprising 10 ppm to 1000 ppm by weight of a sulfur-containing anionic surfactant at the time of use.

14. The composition according to claim 1, wherein the tungsten etching inhibitor contains 1 ppm to 100 ppm by weight of polylysine at the time of use.

15. The composition according to claim 1, wherein the tungsten etching inhibitor comprises 50 ppm by weight to 5000 ppm by weight of glutamic acid, glycine, lysine, or a mixture thereof at the time of use.

16. The composition according to claim 1, having a pH in the range of 2 to 4.

17. The composition according to claim 1, further comprising a hydrogen peroxide oxidizing agent.

18. A chemical mechanical polishing composition, Liquid carriers, Cationic abrasive particles dispersed in a liquid carrier, Iron content enhancer, Tungsten etching inhibitor, Sulfur-containing anionic surfactant and Includes, Having a pH of less than 5, The sulfur-containing anionic surfactant is selected from the group consisting of butanesulfonate, butyl sulfate, pentanesulfonate, pentyl sulfate, hexanesulfonate, hexyl sulfate, butyl ethyl sulfonate, butyl ethyl sulfate, octanesulfonate, octyl sulfate, decanesulfonate, decyl sulfate, dodecanesulfonate, dodecyl sulfate, ethyl 2-hexyl sulfonate, ethyl 2-hexane sulfate, and mixtures thereof. The composition contains 10 ppm to 1000 ppm by weight of a sulfur-containing anionic surfactant. A composition comprising a tungsten etching inhibitor containing 1 ppm to 100 ppm by weight of polylysine at the time of use, or 50 ppm to 5000 ppm by weight of glutamic acid, glycine, lysine, or a mixture thereof at the time of use.

19. A method for chemically and mechanically polishing a patterned tungsten-containing substrate, (a) bringing the substrate into contact with the composition described in claim 1 or 18, (b) Moving the polishing composition relative to the substrate, (c) Polishing the substrate so as to remove a portion of at least one tungsten layer from the substrate, thereby polishing the substrate. A method that includes this.

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