Polysilicon CMP compositions and methods

Abstract

A chemical-mechanical polishing composition for polishing a substrate having a polysilicon layer includes an aqueous liquid carrier, a silica abrasive, a polysilicon accelerator containing an amino acid or a guanidine derivative, and an alkali metal salt. The composition contains less than about 500 ppm of a tetraalkylammonium salt and has a pH within the range of about 10 to about 11.

Description

[Background technology]

[0001] Chemical mechanical polishing is a key enabling technology in integrated circuit (IC) and microelectromechanical systems (MEMS) manufacturing. CMP compositions and methods for polishing (or planarizing) the surface of a substrate (e.g., a wafer) are well known in the art. Polishing compositions (also known as polishing slurries, CMP slurries, and CMP compositions) generally contain abrasive particles suspended (dispersed) in an aqueous solution and chemical additives, such as accelerators, to increase the material removal rate during the CMP operation.

[0002] Polycrystalline silicon (known in the art as polysilicon, poly-Si or p-Si Polysilicon (also called polysilicon) films are widely used in IC and MEMS devices. For example, polysilicon has long been used as the gate electrode material in metal-oxide-semiconductor (MOS) and metal-oxide-semiconductor field-effect transistor (MOSFET) devices. Polysilicon is also used in various damascene / interconnect applications in IC devices generally, as well as in structural components of MEMS devices.

[0003] Commercially available polysilicon CMP slurries typically contain a tetramethylammonium hydroxide (TMAH) chemical accelerator to enhance polysilicon removal rates. While such slurries are known to provide adequate polysilicon removal rates and may be useful in other respects, TMAH is a known hazardous and toxic chemical compound with a Hazardous Materials Identification System (HIMS) rating of 300. TMAH can cause burns on contact with skin and can be toxic to aquatic life. Therefore, there is a real need in the art for polysilicon CMP compositions that are substantially free of TMAH and other tetraalkylammonium compounds, yet also provide high polysilicon removal rates and high selectivity to silicon oxide and silicon nitride layers. Summary of the Invention

[0004] A chemical-mechanical polishing composition for polishing a substrate having a polysilicon layer is disclosed. In one embodiment, the polishing composition comprises, consists of, or consists essentially of an aqueous liquid carrier, about 0.1 to about 3 weight percent silica abrasive particles dispersed in the liquid carrier, about 0.05 to about 1 weight percent polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof, and an alkali metal salt. The composition contains less than about 500 ppm by weight of a tetraalkylammonium salt and has a pH within the range of about 10 to about 11.

[0005] A chemical-mechanical polishing composition for polishing a substrate having a polysilicon layer is disclosed. The polishing composition comprises, consists of, or consists essentially of an aqueous liquid carrier, a silica abrasive, a nitrogen-containing polysilicon polishing accelerator, and an alkali metal salt. The pH of the composition is in the range of about 10 to about 11. In one exemplary embodiment, the composition is substantially free of tetraalkylammonium salts, such as tetramethylammonium salts, tetraethylammonium salts, and tetrabutylammonium salts.

[0006] The disclosed polishing composition and corresponding CMP method can provide significant unexpected advantages. For example, the disclosed polishing composition provides the same high polysilicon polishing removal rate and high removal rate selectivity for both silicon oxide (e.g., TEOS) and silicon nitride. Moreover, the disclosed polishing composition is substantially free of tetraalkylammonium compounds such as TMAH, and therefore tends to have lower environmental impact and reduced risk to human health. DETAILED DESCRIPTION OF THE INVENTION

[0007] The polishing composition contains an abrasive comprising silicon dioxide (silica) particles suspended in an aqueous liquid carrier. The abrasive can comprise virtually any suitable silica particles, including, for example, colloidal silica particles and / or fumed silica particles. As used herein, the term colloidal silica particles refers to silica particles prepared via a wet process rather than a pyrolytic or flame hydrolysis process, which typically produces structurally distinct particles. Such colloidal silica particles can be agglomerated or non-agglomerated. Non-agglomerated particles are individually discrete particles that can be spherical or nearly spherical in shape, but can also have other shapes (e.g., generally elliptical, square, or rectangular cross-sections). Agglomerated particles are particles in which many discrete particles are clustered or bonded together to form aggregates having a generally irregular shape.

[0008] Colloidal silica may be precipitated or condensation-polymerized silica and can be prepared by any method known to those skilled in the art, such as by 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. The precursor Si(OH)4 can be obtained, for example, by hydrolysis of high-purity alkoxysilanes or by acidification of aqueous silicate solutions. Such abrasive particles can be prepared, for example, according to U.S. Pat. No. 5,230,833, or can be obtained from a number of commercial suppliers, including, for example, EKA Chemicals, Fuso Chemical Company, Nalco, DuPont, Bayer, Applied Research, Nissan Chemical, and Clariant.

[0009] Pyrogenic silica (also called fumed silica) is produced via a flame hydrolysis process in which suitable feedstock vapors (e.g., silicon tetrachloride) are burned in a flame of hydrogen and oxygen. Roughly spherical molten particles are formed during the combustion process, and their diameter can be varied via process parameters. These molten spheres, commonly referred to as primary particles, fuse together by collisions at their contact points to form three-dimensional, branched-chain-like aggregates. Fumed silica abrasives are commercially available from a number of suppliers, including, for example, Cabot Corporation, Evonic, and Wacker Chemie.

[0010] Silica abrasive particles can have virtually any suitable particle size. The particle size of particles suspended in a liquid carrier can be defined in the industry using various means. For example, particle size can be defined as the diameter of the smallest sphere that encompasses 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, Prairieville, Louisiana) or a Zetasizer® available from Malvern Instruments®. Such instruments generally measure the average particle size of a silica dispersion.

[0011] The silica abrasive particles can have an average particle size of about 10 nm or more (e.g., about 20 nm or more, about 25 nm or more, or about 30 nm or more). The abrasive particles can have an average particle size of about 200 nm or less (e.g., about 180 nm or less, about 160 nm or less, about 140 nm or less, or about 120 nm or less). It is understood, therefore, that the abrasive particles can have an average particle size within a range bounded by any two of the above endpoints. For example, the abrasive particles can have an average particle size within a range of about 10 nm to about 200 nm (e.g., about 20 nm to about 200 nm, about 25 nm to about 180 nm, about 25 nm to about 160 nm, about 30 nm to about 140 nm, or about 30 nm to about 120 nm).

[0012] It is recognized that the silica abrasive particles are dispersed and suspended in the polishing composition (i.e., in an aqueous liquid carrier). When suspended in the polishing composition, the silica particles are preferably colloidally stable. Colloidally stable means that the silica particles remain suspended in the composition over time. In the context of the present invention, silica abrasive particles are considered colloidally stable when, when placed in a 100 mL graduated cylinder and left unstirred for 2 hours, the difference between the particle concentration in the bottom 50 mL of the cylinder (B in g / mL) and the particle concentration in the top 50 mL of the cylinder (T in g / mL), divided by the initial concentration of particles in the polishing composition (C in g / mL), is 0.5 or less (i.e., (BT) / C≦0.5). More preferably, the value of (BT) / C is 0.3 or less, and most preferably 0.1 or less.

[0013] The polishing composition can contain virtually any suitable amount of silica abrasive particles. If the polishing composition contains too little abrasive, the composition may not exhibit a sufficient removal rate. In contrast, if the polishing composition contains too much abrasive, the polishing composition may exhibit undesirable polishing performance, may not be cost-effective, and / or may lack stability. The polishing composition can contain about 0.05 wt% or more (e.g., about 0.1 wt% or more, about 0.15 wt% or more, about 0.2 wt% or more, or about 0.25 wt% or more) of silica abrasive particles. The abrasive particle concentration in the polishing composition is generally less than about 5 wt%, more typically about 3 wt% or less (e.g., about 2 wt% or less, about 1.5 wt% or less, about 1.2 wt% or less, or about 1 wt% or less). It is understood that the abrasive particles can be present in the polishing composition at a concentration bounded by any two of the above-mentioned endpoints. For example, the concentration of abrasive particles in the polishing composition can be in the range of about 0.05 wt % to about 5 wt %, more preferably about 0.1 wt % to about 3 wt % (e.g., about 0.1 wt % to about 1.5 wt %, about 0.2 wt % to about 1.5 wt %, about 0.2 wt % to about 1.2 wt %, about 0.2 wt % to about 1 wt %, or about 0.25 wt % to about 1 wt %).

[0014] An aqueous liquid carrier is used to facilitate the application of the abrasive and optional chemical additives to the surface of the substrate to be polished (e.g., planarized). By aqueous, it is meant that the liquid carrier is composed of at least 50% by weight of water (e.g., deionized water). The liquid carrier may contain other suitable non-aqueous carriers, including, for example, lower alcohols (e.g., methanol, ethanol, etc.) and ethers (e.g., dioxane, tetrahydrofuran, etc.). Preferably, the liquid carrier consists essentially of water, more preferably deionized water, or consists of water, more preferably deionized water.

[0015] The polishing composition is generally alkaline, having a pH greater than about 7. The polishing composition can have a pH of about 8 or greater (e.g., about 9 or greater or about 10 or greater). Additionally, the polishing composition can have a pH of about 13 or less (e.g., about 12 or less or about 11 or less). It is understood that the polishing composition can have a pH within a range bounded by any two of the above endpoints, e.g., from about 9 to about 12 (e.g., from about 10 to about 11). For example, the pH of the composition can be about 10.5.

[0016] The polishing composition preferably contains an alkali metal hydroxide, such as potassium hydroxide, in an amount suitable to adjust the pH to a desired level. The amount of alkali metal hydroxide needed to adjust the pH can depend on many factors, including, for example, the selected pH of the polishing composition, the amount and type of optional chemical additives, and various properties of the selected silica abrasive particles. In some embodiments, the polishing composition can contain, for example, about 0.01 wt % to about 0.4 wt % (e.g., about 0.02 wt % to about 0.2 wt %) potassium hydroxide.

[0017] The polishing composition further comprises a nitrogen-containing polysilicon polishing accelerator. The nitrogen-containing polishing accelerator may include amino acids and guanidine derivatives. Without wishing to be bound by theory, it is believed that suitable amino acids and guanidine derivatives activate or oxidize the polysilicon surface, thereby promoting rapid removal during chemical mechanical polishing. Suitable amino acids may include arginine, cysteine, glycine, histidine, lysine, methylglycine, trimethylglycine (betaine), or mixtures thereof. Suitable guanidine derivatives may include arginine, creatine, guanidine salts, or mixtures thereof. In a preferred embodiment, the polysilicon polishing accelerator comprises arginine, betaine (trimethylglycine), guanidine carbonate, or mixtures thereof. In one preferred embodiment, the polysilicon polishing accelerator comprises arginine.

[0018] The polysilicon accelerator can be present in the polishing composition in virtually any suitable amount. For example, the concentration of the polysilicon polishing accelerator in the polishing composition can be 0.01 wt% or more (e.g., 0.02 wt% or more, 0.04 wt% or more, 0.06 wt% or more, 0.08 wt% or more, or 0.1 wt% or more). The concentration of the polysilicon polishing accelerator can be less than about 1 wt% (e.g., 0.8 wt% or less, 0.6 wt% or less, 0.5 wt% or less, or 0.4 wt% or less). Polysilicon Accelerator It is understood that the polysilicon polishing accelerator may be present in the polishing composition at a concentration bounded by any two of the above endpoints. For example, the concentration of the polysilicon polishing accelerator in the polishing composition may be within the range of about 0.01 wt % to about 1 wt % (e.g., about 0.02 wt % to about 1 wt %, about 0.02 wt % to about 0.8 wt %, about 0.04 wt % to about 0.8 wt %, about 0.04 wt % to about 0.6 wt %, about 0.06 wt % to about 0.6 wt %, about 0.08 wt % to about 0.5 wt %, or about 0.1 wt % to about 0.4 wt %). In one exemplary embodiment, the polishing composition contains about 0.05 wt % to about 0.5 wt % of the polysilicon polishing accelerator.

[0019] The polishing composition may further include other optional additives, including, for example, secondary polysilicon accelerators, chelating agents, stabilizers, and biocides. Such additives are merely optional. The disclosed embodiments are not so limited and may require the use of any one or more of such additives.

[0020] In some embodiments, the polishing composition may contain one or more of the following optional additives: (i) a potassium salt polysilicon accelerator, (ii) an aminophosphonic acid silica chelating agent, (iii) a heterocyclic amine polysilicon accelerator, and (iv) a hydroxy acid polysilicon accelerator. For example, the polishing composition may contain a potassium salt polysilicon accelerator. Without wishing to be bound by theory, it is believed that the potassium salt may function to adjust the conductivity of the composition, thereby promoting activation of the polysilicon. The potassium salt may include virtually any suitable potassium salt, including, for example, potassium chloride, potassium bromide, potassium iodide, potassium bicarbonate, and mixtures thereof.

[0021] In optional embodiments containing a potassium salt, the polishing composition may contain about 0.01 wt. % or more (e.g., about 0.02 wt. % or more, about 0.03 wt. % or more, about 0.04 wt. % or more, or about 0.05 wt. % or more) of potassium salt. In such optional embodiments, the polishing composition may contain about 1 wt. % or less (e.g., about 0.8 wt. % or less, about 0.6 wt. % or less, about 0.4 wt. % or less, or about 0.2 wt. % or less) of potassium salt. It is understood that the potassium salt may optionally be present in the polishing composition at a concentration bounded by any two of the above-mentioned endpoints. For example, the concentration of the potassium salt in optional embodiments may be within the range of about 0.01 wt. % to about 1 wt. % (e.g., about 0.02 wt. % to about 0.8 wt. %, about 0.02 wt. % to about 0.6 wt. %, about 0.04 wt. % to about 0.4 wt. %, or about 0.5 wt. % to about 0.2 wt. %). In one exemplary embodiment, the polishing composition comprises about 0.03 wt % to about 0.3 wt % potassium bicarbonate.

[0022] The polishing composition may optionally contain an aminophosphonic acid silica chelating agent. Without wishing to be bound by theory, it is believed that the aminophosphonic acid acts as a silica chelating agent, thereby increasing the polysilicon polishing rate in some compositions. The silica chelating agent can include virtually any suitable aminophosphonic acid, including, for example, ethylenediaminetetra(methylenephosphonic acid), aminotri(methylenephosphonic acid), diethylenetriaminepenta(methylenephosphonic acid), salts thereof, and combinations thereof. A preferred aminophosphonic acid is aminotri(methylenephosphonic acid). An exemplary aminophosphonic acid is DEQUEST™ 2000EG, commercially available from ThermPhos International.

[0023] In optional embodiments containing aminophosphonic acid, the polishing composition can contain about 0.002 wt. % or more (e.g., about 0.004 wt. % or more, about 0.006 wt. % or more, about 0.008 wt. % or more, or about 0.01 wt. % or more) of aminophosphonic acid. In such optional embodiments, the polishing composition can contain about 0.5 wt. % or less (e.g., about 0.2 wt. % or less, about 0.15 wt. % or less, about 0.1 wt. % or less, about 0.08 wt. % or less, or about 0.06 wt. % or less) of aminophosphonic acid. It is understood that the aminophosphonic acid can optionally be present in the polishing composition at a concentration bounded by any two of the above-mentioned endpoints. For example, the concentration of the aminophosphonic acid in optional embodiments can be in the range of about 0.002% to about 0.5% by weight (e.g., about 0.002% to about 0.2% by weight, about 0.006% to about 0.15% by weight, about 0.006% to about 0.1% by weight, or about 0.01% to about 0.1% by weight).

[0024] The polishing composition may optionally contain a heterocyclic amine secondary polysilicon accelerator and / or a hydroxy acid secondary polysilicon accelerator. The heterocyclic amine may include a heterocyclic aromatic amine or a heterocyclic aliphatic amine. A preferred heterocyclic aromatic amine is 1,2,4-triazole. A preferred heterocyclic aliphatic amine is aminoethylpiperazine. The hydroxyl acid may include, for example, glycolic acid, lactic acid, malic acid, citric acid, and / or tartaric acid. Citric acid and lactic acid are preferred hydroxyl acids.

[0025] In optional embodiments containing a secondary polysilicon accelerator, the polishing composition may contain about 0.002 wt. % or more (e.g., about 0.004 wt. % or more, about 0.006 wt. % or more, about 0.008 wt. % or more, or about 0.01 wt. % or more) of the secondary polysilicon accelerator. In such optional embodiments, the polishing composition may contain about 0.5 wt. % or less (e.g., about 0.2 wt. % or less, about 0.15 wt. % or less, about 0.1 wt. % or less, about 0.08 wt. % or less, or about 0.06 wt. % or less) of the secondary polysilicon accelerator. It is understood that the secondary polysilicon accelerator may optionally be present in the polishing composition at a concentration bounded by any two of the above-mentioned endpoints. For example, the concentration of the secondary polysilicon promoter in any embodiment may be in the range of about 0.002 wt % to about 0.5 wt % (e.g., about 0.002 wt % to about 0.2 wt %, about 0.006 wt % to about 0.15 wt %, about 0.006 wt % to about 0.1 wt %, or about 0.01 wt % to about 0.1 wt %).

[0026] The polishing composition may optionally further comprise a biocide. The biocide may comprise virtually any suitable biocide, such as an isothiazolinone biocide, such as methylisothiazolinone or benzisothiazolinone. The amount of biocide in the polishing composition is typically in the range of about 1 ppm to about 50 ppm, preferably about 1 ppm to about 20 ppm.

[0027] The polishing composition is preferably substantially free of tetraalkylammonium salts, including, for example, tetramethylammonium salts, tetraethylammonium salts, tetrapropylammonium salts, tetrabutylammonium salts, cetyltrimethylammonium salts, and the like. Such salts include, for example, tetraalkylammonium hydroxides, chlorides, bromides, and the like. In a preferred embodiment, the polishing composition is substantially free of tetraalkylammonium salts, meaning that no tetraalkylammonium salts are intentionally added to the polishing composition, and therefore the intended concentration of tetraalkylammonium salts is essentially zero. However, the disclosed embodiments are not so strictly limited. More generally, substantially free means that the polishing composition contains less than 1000 ppm by weight (0.1% by weight) of tetraalkylammonium salts (e.g., less than 500 ppm, less than 200 ppm, less than 100 ppm, less than 20 ppm, less than 10 ppm, less than 5 ppm, less than 1 ppm, less than 0.5 ppm, or less than 0.1 ppm).

[0028] The polishing composition can be prepared using any suitable technique, many of which are known to those skilled in the art. The polishing composition may be prepared in a batch or 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., abrasive particles, polysilicon accelerator, and any optional additives).

[0029] It is understood that any of the components of the polishing composition that are salts (e.g., potassium salts, alkali metal hydroxides, aminophosphonic acids, etc.) can exist in dissociated forms as cations and anions when dissolved in the water of the polishing composition. The amount of salt present in the polishing composition described herein is understood to mean the weight of the undissociated salt used in preparing the polishing composition. For example, the weight of an alkali metal hydroxide (e.g., potassium hydroxide) means the amount of potassium salt obtained from its empirical formula (e.g., KOH).

[0030] In one example, the silica abrasive may be dispersed in an aqueous liquid carrier. Other components, such as a polysilicon accelerator, and optional additives may then be added and mixed by any method that allows the components to be incorporated into the polishing composition. For example, these components may be dissolved in water (in any order, or simultaneously) to obtain an aqueous solution. The silica dispersion may then be added to the aqueous solution (or alternatively, the aqueous solution may be added to the silica dispersion) to obtain the polishing composition. The pH may be adjusted at any suitable time, for example, before or after combining the silica dispersion and the aqueous solution. In one embodiment, a predetermined amount of KOH is added to the aqueous solution before combining it with the silica dispersion. The pH is then checked to ensure that it is within a predetermined range.

[0031] The polishing composition of the present invention can be provided as a concentrate intended to be diluted with an appropriate amount of water before use. In such an embodiment, the polishing composition concentrate can contain the above-mentioned abrasive particles, polysilicon accelerator, and other optional additives in amounts such that, upon dilution of the concentrate with an appropriate amount of water, each component of the polishing composition will be present in the polishing composition in an amount within the appropriate range described above for each component. For example, the silica abrasive particles, polysilicon accelerator, and other optional additives can each be present in the polishing composition in an amount about 3 times (e.g., about 4 times, about 5 times, about 6 times, about 7.5 times, about 10 times, about 15 times, about 20 times, about 25 times, about 30 times, or about 50 times) greater than the concentration described above for each component, and the concentrate can be added to an equal volume of water (For example, 2 equal volumes of water, 3 equal volumes of water, and 4 equal volumes of water, respectively. 、5When diluted with an equal volume of water, 6.5 equal volumes of water, 9 equal volumes of water, 14 equal volumes of water, 19 equal volumes of water, 24 equal volumes of water, 29 equal volumes of water, or even about 49 equal volumes of water, each component will be present in the polishing composition in an amount within the range defined above for each component. Additionally, as will be understood by those skilled in the art, the concentrate may contain an appropriate proportion of water that will be present in the final polishing composition to ensure that the other components are at least partially or completely dissolved in the concentrate.

[0032] The polishing method of the present invention is particularly suitable for use in conjunction with a chemical mechanical polishing (CMP) apparatus. Typically, the apparatus includes a platen that is in operation during use and has a speed resulting from orbital, linear, or circular motion, a polishing pad that contacts the platen and moves with the platen during operation, and a carrier that holds a substrate so that it contacts the surface of the polishing pad and moves relative to this surface 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 abrade at least a portion of the substrate (e.g., a polysilicon layer) and polish the substrate.

[0033] Although the polishing composition of the present invention can be used to polish any substrate, the polishing composition is particularly useful for polishing substrates containing silicon, particularly polycrystalline silicon (polysilicon) layers.The polishing composition can be particularly advantageous for polishing substrates that further contain silicon oxide, such as tetraethyl orthosilicate (TEOS) and silicon nitride (SiN) layers.For example, the polishing composition can be advantageously used in CMP operations where high removal rate selectivity of polysilicon to silicon oxide and polysilicon to silicon nitride is desired (i.e., high removal rate ratios of polysilicon to silicon oxide and polysilicon to silicon nitride).For example, if desired, the polishing composition can be used to polish substrates whose polishing selectivity of polysilicon to silicon oxide is about 10:1 or more (e.g., about 20:1 or more, about 40:1 or more, about 50:1 or more, about 100:1 or more, or about 150:1 or more). Similarly, the chemical-mechanical polishing compositions of the present invention can be used to polish substrates having a polysilicon-to-silicon nitride polishing selectivity of about 10:1 or greater (e.g., about 20:1 or greater, about 40:1 or greater, about 50:1 or greater, about 100:1 or greater, or about 150:1 or greater). In combination with certain CMP polishing parameters, some formulations may exhibit even higher polysilicon-to-silicon oxide and polysilicon-to-silicon nitride polishing selectivities, e.g., about 200:1 or greater.

[0034] Any suitable polishing pad (e.g., polishing surface) can be used to planarize or polish a substrate with the chemical-mechanical polishing composition. Suitable polishing pads include, for example, woven or nonwoven polishing pads. Furthermore, suitable polishing pads can include any suitable polymer with various densities, hardnesses, thicknesses, compressibility, rebound capacity upon compression, and compression moduli. Suitable polymers include, for example, polyvinyl chloride, polyvinyl fluoride, nylon, fluorocarbon, polycarbonate, polyester, polyacrylate, polyether, polyethylene, polyamide, polyurethane, polystyrene, polypropylene, co-formed products thereof, and mixtures thereof.

[0035] It will be understood that the present disclosure includes numerous embodiments, including but not limited to the following:

[0036] In a first embodiment, a chemical-mechanical polishing composition for polishing a substrate containing a polysilicon layer is disclosed. The composition can include an aqueous liquid carrier; about 0.1 to about 3 weight percent silica abrasive particles dispersed in the liquid carrier; about 0.05 to about 1 weight percent polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; and an alkali metal salt, wherein the composition has a pH within the range of about 10 to about 11; and the composition contains less than 500 ppm by weight of a tetraalkylammonium salt.

[0037] A second embodiment can include the first embodiment and includes about 0.2 to about 1.5 weight percent silica abrasive particles.

[0038] A third embodiment may include any one of the first or second embodiments and includes about 0.1 to about 0.5 weight percent polysilicon promoter.

[0039] A fourth embodiment can include any one of the first to third embodiments, wherein the polysilicon accelerator is arginine, trimethylglycine, guanidine carbonate, or a mixture thereof.

[0040] A fifth embodiment can include any one of the first to third embodiments, wherein the polysilicon accelerator is a guanidine derivative.

[0041] A sixth embodiment can include any one of the first through fifth embodiments and can further include about 0.01 to about 0.5 weight percent of a heterocyclic amine.

[0042] A seventh embodiment can include the sixth embodiment, wherein the heterocyclic amine is a triazole compound.

[0043] An eighth embodiment can include any one of the first through seventh embodiments and can further include about 0.05 to about 0.5 weight percent of an aminophosphonic acid compound.

[0044] A ninth embodiment can include the eighth embodiment, wherein the aminophosphonic acid compound is aminotrimethylene phosphonic acid.

[0045] A tenth embodiment can include any one of the first to ninth embodiments and can further include about 0.01 to about 1 weight percent of a potassium salt.

[0046] An eleventh embodiment can include any one of the first through ninth embodiments and can further include about 0.03 to about 0.3 weight percent potassium bicarbonate.

[0047] A twelfth embodiment can include any one of the first to eleventh embodiments, and can further include 0.05 to about 0.5 weight percent aminotrimethylene phosphonic acid; and about 0.03 to about 0.3 weight percent potassium bicarbonate, where the polysilicon accelerator is arginine.

[0048] A thirteenth embodiment can include any one of the first to twelfth embodiments, wherein the composition comprises less than about 10 ppm of a tetraalkylammonium salt.

[0049] A fourteenth embodiment discloses a method for chemical mechanical polishing a substrate containing a polysilicon material, the method comprising the steps of: (a) providing a polysilicon polishing composition comprising an aqueous liquid carrier; about 0.1 to about 3 weight percent silica abrasive particles dispersed in the liquid carrier; about 0.05 to about 1 weight percent polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; and an alkali metal salt, wherein the composition has a pH within a range of about 10 to about 11; and the composition contains less than 500 ppm by weight of a tetraalkylammonium salt; (b) contacting the substrate with the chemical mechanical polishing composition; (c) moving the polishing composition relative to the substrate; and (d) polishing the substrate to remove a portion of the silicon-oxygen-containing material from the substrate, thereby polishing the substrate.

[0050] A fifteenth embodiment includes the fourteenth embodiment, wherein the substrate further comprises a silicon oxide material and a silicon nitride material; in (d), the removal rate selectivity of the polysilicon material to the silicon oxide material is about 50:1 or greater; and in (d), the removal rate selectivity of the polysilicon material to the silicon nitride material is about 50:1 or greater.

[0051] A sixteenth embodiment can include any one of the fourteenth or fifteenth embodiments, wherein the polishing composition comprises from about 0.2 to about 1.5 weight percent silica abrasive particles and from about 0.1 to about 0.5 weight percent polysilicon accelerator; and the polysilicon accelerator is a guanidine derivative.

[0052] A seventeenth embodiment includes the sixteenth embodiment, wherein the polishing composition further contains 0.05 to about 0.5 weight percent aminotrimethylene phosphonic acid and about 0.03 to about 0.3 weight percent potassium bicarbonate; and the polysilicon accelerator is arginine.

[0053] An eighteenth embodiment can include any one of the fourteenth or seventeenth embodiments, wherein the polishing composition comprises less than about 10 ppm of a tetraalkylammonium salt.

[0054] A nineteenth embodiment discloses a method for chemical mechanical polishing of a substrate containing a polysilicon material, the method comprising: (a) providing a concentrated polysilicon polishing composition comprising an aqueous liquid carrier; about 1 to about 15 weight percent silica abrasive particles dispersed in the liquid carrier; about 0.5 to about 10 weight percent polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; an alkali metal salt; and less than 0.1 weight percent tetraalkylammonium salt; (b) adding one part concentrated polishing composition to about 5 to about 30 parts water to obtain a point-of-use polishing composition having a pH in the range of about 10 to about 11; (c) moving the polishing composition relative to the substrate; and (d) abrading the substrate to remove a portion of the silicon-oxygen-containing material from the substrate, thereby polishing the substrate.

[0055] A twentieth embodiment includes the nineteenth embodiment, wherein the substrate further includes a silicon oxide material and a silicon nitride material; and a polysilicon material. : The removal rate selectivity for silicon oxide materials is greater than about 50:1; for polysilicon materials : The removal rate selectivity of the silicon nitride material is greater than about 50:1.

[0056] The following examples further illustrate the present invention but, of course, should not be construed as limiting the scope of the present invention in any way. Polysilicon-containing substrates were polished using either an Applied Materials Mirra® polishing tool or a Logitech benchtop polisher. On the Mirra®, the substrates were polished for 60 seconds at a platen speed of 93 rpm, a head speed of 87 rpm, a downforce of 3 psi, and a slurry flow rate of 125 ml / min. The substrates were polished on an IC1010 pad (available from Dow) using a 3M-A189L conditioner. On the Logitech, the substrates were polished for 60 seconds at a platen speed of 100 rpm, a head speed of 85 rpm, a downforce of 3 psi, and a slurry flow rate of 45 ml / min. The substrates were polished on either an IC1010 pad (available from Dow) or a D100 pad (available from Cabot Microelectronics) using a Saesol C7 conditioner.

[0057] In the following examples, blanket polysilicon, TEOS, and / or SiN wafers were polished. The polysilicon wafers were obtained from Novarti and contained a 10,000 Å polysilicon layer. The TEOS wafers were obtained from Advantec and contained a 15,000 Å TEOS layer. The SiN wafers were also obtained from Advantec and contained a 5,000 Å PE-SiN layer. [Example]

[0058] Example 1 Three polishing compositions were evaluated on Mirra® tools. The control composition contained a TMAH polysilicon polishing accelerator. Compositions 1A and 1B contained an L-arginine polysilicon polishing accelerator without TMAH. The control composition was prepared as a 15x concentrate and contained (a) 13.125 wt.% silica (Nalco DVSTS006 silica particles), (b) 2.63 wt.% TMAH, (c) 1.3 wt.% KHCO3, (d) 0.79 wt.% KOH, (e) 0.39 wt.% DEQUEST® 2000EG, and (f) 0.33 wt.% 1,2,4-triazole in deionized water. Prior to polishing, one part of the control composition was mixed with 14 parts water to obtain a pre-polishing point-of-use control. The pH at the point-of-use (diluted) was approximately 10.5. Compositions 1A and 1B were also prepared as 15x concentrates, containing (i) 13.125 wt.% silica (Nalco DVSTS006 silica particles), (ii) 5.03 wt.% L-arginine (1A) or 2.51 wt.% L-arginine (1B), (iii) 1.31 wt.% KHCO3, (d) 0.79 wt.% KOH, (e) 0.39 wt.% aminotri(methylenephosphonic acid) (DEQUEST® 2000EG), and (f) 0.33 wt.% 1,2,4-triazole in deionized water. Prior to polishing, 1 part each of Compositions 1A and 1B was mixed with 14 parts water to provide a pre-polishing point-of-use control. The pH at the point-of-use (diluted) was approximately 10.5. The molar concentration of L-arginine in Polishing Composition 1A was the same as the molar concentration of TMAH in the control (0.289 M).

[0059] Blanket polysilicon, TEOS, and SiN wafers were polished for 60 seconds on a Mirra® tool under the conditions listed above. The polishing results are shown in Table 1. All removal rates (RR) are listed in Angstroms per second (Å / min).

[0060] [Table 1]

[0061] It is readily apparent from the results set forth in Table 1 that compositions 1A and 1B utilizing the L-arginine polysilicon accelerator can achieve high polysilicon removal rates (nearly equivalent to the TMAH-containing control). Moreover, compositions 1A and 1B achieved superior removal rate selectivity to TEOS and SiN.

[0062] Example 2 Nine polishing compositions were evaluated on a Logitech desktop polisher. The control composition was identical to the control in Example 1. Composition 1B was identical to Composition 1B in Example 1. Compositions 2A, 2B, 2C, 2D, 2E, 2F, and 2G contained alternative polysilicon polishing accelerators but were otherwise identical to Composition 1B. The alternative polysilicon polishing accelerators included L-lysine (2A), L-histidine (2B), guanidine carbonate (2C), glycine (2D), citric acid (2E), trimethylglycine (betaine) (2F), and cysteine ​​(2G) in molar concentrations identical to the molar concentration of L-arginine in Composition 1B (0.145M).

[0063] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using a D100 pad under the conditions described above. The polishing results are shown in Table 2. All removal rates (RR) are listed in angstroms per minute (Å / min).

[0064] [Table 2]

[0065] As is readily apparent from the results shown in Table 2, the amino acid and guanidine derivative polysilicon polishing accelerators can achieve high polysilicon removal rates and better removal rate selectivity to TEOS and SiN. Compositions 1B, 2C, and 2F were generally considered superior because silica particle growth was observed in the concentrate compositions for compositions 2A, 2B, 2D, 2E, and 2G.

[0066] As is evident from the results shown in Table 3, high polysilicon removal rates can be achieved for polishing compositions with low silica concentrations. However, for abrasive-free compositions, the removal rate was essentially zero (0 wt. % silica). The removal rate for such abrasive-free compositions was very low. expensive Even when concentrations of polysilicon polishing accelerators were used, they were essentially zero, demonstrating that abrasive-free compositions are not feasible.

[0067] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using a D100 pad under the conditions described above. The polishing results are shown in Table 3. All removal rates (RR) are listed in angstroms per minute (Å / min).

[0068] [Table 3]

[0069] As is evident from the results shown in Table 3, high polysilicon removal rates can be achieved for polishing compositions with low silica concentrations. However, for compositions without abrasives, the removal rate was essentially zero (0 wt. % silica). The removal rate for such abrasive-free compositions was essentially zero even when very high concentrations of polysilicon polishing accelerators were used, demonstrating the impossibility of abrasive-free compositions.

[0070] Example 4 Five polishing compositions were evaluated on a Logitech desktop polishing machine to assess the effect of dilution. The control composition was identical to the control in Example 1. Composition 4A was prepared as a 10x concentrate and contained 0.0 wt. % of 1, 2, 4 - Composition 4A was identical to Composition 1A in Example 1, except that it contained 1,2,4-triazole, resulting in a concentrate containing (i) 8.75 wt.% silica (Nalco DVSTS006 silica particles), (ii) 3.35 wt.% L-arginine, (iii) 0.87 wt.% KHCO3, (d) 0.53 wt.% KOH, (e) 0.26 wt.% aminotri(methylenephosphonic acid) (DEQUEST® 2000EG), and (f) 0.0 wt.% 1,2,4-triazole in deionized water. As in Examples 1, 2, and 3, Composition 4A was diluted with 1 part concentrate to 9 parts water prior to polishing. Compositions 4B, 4C, and 4D were identical to Composition 4A, but were diluted with 14 (4B), 24 (4C), and 34 (4D) parts water to 1 part concentrate prior to polishing.

[0071] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using an IC1010 pad under the conditions described above. The polishing results are shown in Table 4. All removal rates (RR) are listed in Angstroms per minute (Å / min).

[0072] [Table 4]

[0073] As is evident in the data presented in Table 4, polysilicon removal rates were observed to decrease monotonically with over-dilution (i.e., with decreasing point-of-use concentrations of silica abrasive and L-arginine). However, even better removal rate selectivity to TEOS and SiN was also observed for over-diluted compositions (i.e., compositions containing lower point-of-use concentrations of silica abrasive and L-arginine).

[0074] Example 5 Six polishing compositions were evaluated on a Logitech desktop polishing machine. - The effects of triazole and potassium bicarbonate were evaluated. The control composition was the same as the control in Example 1. Composition 1B was the same as Composition 1B in Example 1. Compositions 5A and 5B were prepared by adding different 1, 2, 4 - Composition 5A contained 0.16 wt. % of 1,2,4 triazole but was otherwise identical to Composition 1B. - triazole, while Composition 5B contained no triazole (0.0 wt. % of 1,2,4 - triazole). Compositions 5C and 5D contained different KHCO3 concentrations but were otherwise identical to Composition 1B. Composition 5C contained 0.655 wt% KHCO3, while Composition 5D contained no potassium bicarbonate (0.0 wt% KHCO3).

[0075] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using a D100 pad under the conditions described above. The polishing results are shown in Table 5. All removal rates (RR) are listed in angstroms per minute (Å / min).

[0076] [Table 5]

[0077] As is evident from the data presented in Table 5, 1,2,4-triazole had essentially no effect on the removal rates of polysilicon, TEOS, and SiN. The polysilicon removal rate was reduced by about 10% without KHCO. Halving the KHCO concentration had no effect on the removal rates of polysilicon, TEOS, and SiN.

[0078] Example 6 Five polishing compositions were evaluated on a Logitech desktop polisher to evaluate the effect of alternative potassium salts. Composition 4B was identical to composition 4B in Example 4. Compositions 6A, 6B, 6C, and 6D were identical to composition 4B in Example 4, except that (i) composition 6A contained an equimolar amount of KCl instead of KHCO3, (ii) composition 6B contained twice the molar amount of KCl instead of KHCO3, (iii) composition 6C contained an equimolar amount of KBr instead of KHCO3, and (iv) composition 6D contained an equimolar amount of KI instead of KHCO3. The electrical conductivities of the point-of-use compositions were 3.55 mS / cm (4B), 2.34 mS / cm (6A), and 3.35 mS / cm (6B).

[0079] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using an IC1010 pad under the conditions described above. The polishing results are shown in Table 6. All removal rates (RR) are listed in angstroms per minute (Å / min).

[0080] [Table 6]

[0081] As is evident from the data presented in Table 6, the polysilicon removal rate is not strongly affected by the potassium salt selected or the conductivity.

[0082] Example 7 Three polishing compositions were evaluated on a Logitech desktop polisher to evaluate the effect of pH on polysilicon removal rate. Compositions 7A, 7B, and 7C were identical to composition 4A of Example 4, except that the amount of KOH was adjusted so that the pH of the point-of-use compositions was 10.0 (7A), 10.5 (7B), and 11.0 (7C).

[0083] Blanket polysilicon wafers were polished for 60 seconds on a Logitech desktop polisher using a D100 pad under the conditions described above. The polishing results are shown in Table 7. The removal rate (RR) is listed in Angstroms per minute (Å / min).

[0084] [Table 7]

[0085] As is evident from the data shown in Table 7, the polysilicon removal rate is high at pH values ​​of 10.0, 10.5, and 11.0. The polysilicon removal rate is highest at pH 10.5.

[0086] Example 8 Eight polishing compositions were evaluated on a Logitech desktop polishing machine. Compositions 8A and 8B were identical to compositions 5B and 1B of corresponding Examples 5 and 1, except that they were prepared as 7.5x concentrates and therefore contained (i) 6.56 wt.% silica (Nalco DVSTS006 silica particles), (ii) 1.26 wt.% L-arginine, (iii) 0.65 wt.% KHCO3, (d) 0.39 wt.% KOH, (e) 0.19 wt.% aminotri(methylenephosphonic acid) (DEQUEST® 2000EG), and (f) 0.165 wt.% 1,2,4-triazole (8A) or 0.0 wt.% 1,2,4-triazole (8B) in deionized water. Compositions 8C, 8E, and 8G were identical to composition 8A, except that they contained alternative colloidal silica. Compositions 8D, 8E, and 8G were identical to composition 8A, except that they contained alternative colloidal silica. Fand 8H were identical to composition 8B except that they contained alternative colloidal silica. Compositions 8C and 8D contained Fuso PL-3 colloidal silica. Compositions 8E and 8F contained Fuso PL-5 colloidal silica. Compositions 8G and 8H contained Fuso PL-7 colloidal silica. One portion of each of compositions 8A, 8B, 8C, 8D, 8E, 8F, 8G, and 8H was mixed with 6.5 parts deionized water to obtain point-of-use polishing compositions.

[0087] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using an IC1010 pad under the conditions described above. The polishing results are shown in Table 8. All removal rates (RR) are listed in Angstroms per minute (Å / min).

[0088] [Table 8]

[0089] It is immediately apparent that the polysilicon polishing rate is not strongly affected by silica particle size in the range of about 65 nm to about 120 nm.

[0090] Example 9 Six polishing compositions were evaluated on Mirra® abrasive tools to confirm some observations made using a Logitech desktop polishing machine. The control composition was identical to the control in Example 1. Compositions 9A and 9B were identical to Compositions 1A and 1B in Example 1, except that they were prepared as 10x concentrates and therefore contained (i) 8.75 wt.% silica (Nalco DVSTS006 silica particles), (ii) 3.35 wt.% L-arginine (9A) or 1.67 wt.% L-arginine (9B), (iii) 0.87 wt.% KHCO3, (d) 0.53 wt.% KOH, (e) 0.26 wt.% aminotri(methylenephosphonic acid) (DEQUEST® 2000EG), and (f) 0.22 wt.% 1,2,4-triazole in deionized water. Composition 9C was identical to Composition 9A except that it contained 5.83 wt.% silica in the concentrate (a one-third reduction from Composition 9A). Composition 9D contained no triazole (0.0 wt.% of 1,2,4 - Composition 9E was identical to Composition 9A of Example 1 except that it contained no triazole (0.0 wt. % of 1,2,4 - It was identical to composition 9C except that it contained 1,2-dichloro-2,2-triazole.

[0091] Blanket polysilicon, TEOS wafers, and SiN wafers were polished for 60 seconds on a Logitech desktop polisher using an IC1010 pad under the conditions described above. The polishing results are shown in Table 9. All removal rates (RR) are listed in Angstroms per minute (Å / min).

[0092] [Table 9]

[0093] As is evident from the data presented in Table 9, each of the compositions achieved a high polysilicon removal rate. stomach((one-third reduction) silica concentration, which achieved higher removal rate selectivity for both TEOS and SiN.

[0094] The use of the terms "a," "an," and "the," and similar referents in the context of describing the present invention (particularly in the context of the claims which follow) should be construed as covering both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" should be considered as open-ended terms (i.e., "including, but not limited to"), unless otherwise indicated. The recitation of ranges of values ​​herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate 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 clearly contradicted by context. The use of any and all examples or exemplary language (e.g., "such as") provided herein is intended merely to better illustrate the invention and does not limit 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.

[0095] Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors anticipate that skilled artisans will utilize such variations as appropriate, and the inventors intend that the invention may 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. Furthermore, any combination of the above-described elements in all possible variations thereof is encompassed by the present invention unless otherwise indicated herein or otherwise clearly contradicted by context. The following embodiments can be given as examples of the present invention. (Appendix 1) 1. A chemical-mechanical polishing composition for polishing a substrate containing a polysilicon layer, comprising: aqueous liquid carrier; about 0.1 to about 3 weight percent silica abrasive particles dispersed in said liquid carrier; about 0.05 to about 1 weight percent of a polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; alkali metal salts Including, having a pH within the range of about 10 to about 11; and A composition comprising less than about 500 ppm by weight of a tetraalkylammonium salt. (Appendix 2) 10. The composition of claim 1, comprising about 0.2 to about 1.5 weight percent of the silica abrasive particles. (Appendix 3) 10. The composition of claim 1, comprising about 0.1 to about 0.5 weight percent of the polysilicon promoter. (Appendix 4) 2. The composition of claim 1, wherein the polysilicon accelerator is arginine, trimethylglycine, guanidine carbonate, or a mixture thereof. (Appendix 5) 2. The composition of claim 1, wherein the polysilicon accelerator is a guanidine derivative. (Appendix 6) 10. The composition of claim 1, further comprising about 0.01 to about 0.5 weight percent of a heterocyclic amine. (Appendix 7) 7. The composition of claim 6, wherein the heterocyclic amine is a triazole compound. (Appendix 8) 10. The composition of claim 1, further comprising about 0.05 to about 0.5 weight percent of an aminophosphonic acid compound. (Appendix 9) 9. The composition of claim 8, wherein the aminophosphonic acid compound is aminotrimethylene phosphonic acid. (Appendix 10) 10. The composition of claim 1, further comprising about 0.01 to about 1 weight percent of a potassium salt. (Appendix 11) 11. The composition of claim 10, comprising about 0.03 to about 0.3 weight percent potassium bicarbonate. (Appendix 12) 0.05 to about 0.5 weight percent aminotrimethylenephosphonic acid; about 0.03 to about 0.3 weight percent potassium bicarbonate; 2. The composition of claim 1, further comprising: (Appendix 13) 10. The composition of claim 1, comprising less than about 10 ppm of a tetraalkylammonium salt. (Appendix 14) 1. A method of chemical mechanical polishing a substrate comprising a polysilicon material, comprising: (a) an aqueous liquid carrier; about 0.1 to about 3 weight percent silica abrasive particles dispersed in said liquid carrier; about 0.05 to about 1 weight percent of a polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; alkali metal salts providing a polysilicon polishing composition comprising: the composition has a pH in the range of about 10 to about 11; and the composition comprising less than about 500 ppm by weight of a tetraalkylammonium salt; (b) contacting the substrate with the chemical-mechanical polishing composition; (c) moving the polishing composition relative to the substrate; (d) abrading the substrate to remove a portion of the silicon-oxygen containing material from the substrate, thereby polishing the substrate. (Appendix 15) the substrate further comprises a silicon oxide material and a silicon nitride material; (d) wherein the removal rate selectivity of the polysilicon material to the silicon oxide material is greater than or equal to about 50:1; 15. The method of claim 14, wherein in (d), the removal rate selectivity of the polysilicon material to the silicon nitride material is about 50:1 or greater. (Appendix 16) the polishing composition comprising from about 0.2 to about 1.5 weight percent of the silica abrasive particles and from about 0.1 to about 0.5 weight percent of the polysilicon accelerator; 15. The method of claim 14, wherein the polysilicon accelerator is a guanidine derivative. (Appendix 17) the polishing composition further comprises 0.05 to about 0.5 weight percent aminotrimethylene phosphonic acid and about 0.03 to about 0.3 weight percent potassium bicarbonate; 17. The method of claim 16, wherein the polysilicon promoter is arginine. (Appendix 18) 15. The method of claim 14, wherein the polishing composition comprises less than about 10 ppm of a tetraalkylammonium salt. (Appendix 19) 1. A method of chemical mechanical polishing a substrate comprising a polysilicon material, comprising: (a) an aqueous liquid carrier; about 1 to about 15 weight percent silica abrasive particles dispersed in said liquid carrier; about 0.5 to about 10 weight percent of a polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; with alkali metal salts; less than about 0.1 weight percent of a tetraalkylammonium salt; providing a concentrated polysilicon polishing composition comprising: (b) adding 1 part of the concentrated polishing composition to about 5 to about 30 parts of water to obtain a point-of-use polishing composition having a pH in the range of about 10 to about 11; (c) moving the polishing composition relative to the substrate; (d) abrading the substrate to remove a portion of the silicon-oxygen containing material from the substrate, thereby polishing the substrate. (Appendix 20) the substrate further comprises a silicon oxide material and a silicon nitride material; the removal rate selectivity between the polysilicon material and the silicon oxide material is greater than or equal to about 50:1; 20. The method of claim 19, wherein the removal rate selectivity between the polysilicon material and the silicon nitride material is about 50:1 or greater.

Claims

1. 1. A chemical-mechanical polishing composition for polishing a substrate containing a polysilicon layer, comprising: an aqueous liquid carrier; 0.1 to 3 weight percent silica abrasive particles dispersed in said liquid carrier; 0.05 to 1 weight percent of a polysilicon accelerator which is arginine, trimethylglycine, guanidine carbonate, or a mixture thereof; alkali metal salts Including, the composition further comprises 0.01 to 1 weight percent of a potassium salt and 0.01 to 0.5 weight percent of a heterocyclic amine; the composition has a pH in the range of 10 to 11; the composition further comprising 0.05 to 0.5 weight percent of an aminophosphonic acid compound; the composition comprises less than 500 ppm by weight of a tetraalkylammonium salt; and A composition, wherein the composition comprises 0.03 to 0.3 weight percent potassium bicarbonate.

2. 1. A chemical-mechanical polishing composition for polishing a substrate containing a polysilicon layer, comprising: an aqueous liquid carrier; 0.1 to 3 weight percent silica abrasive particles dispersed in said liquid carrier; 0.05 to 1 weight percent of a polysilicon accelerator which is a guanidine derivative; alkali metal salts Including, the composition further comprises 0.01 to 1 weight percent of a potassium salt and 0.01 to 0.5 weight percent of a heterocyclic amine; the composition has a pH in the range of 10 to 11; the composition further comprising 0.05 to 0.5 weight percent of an aminophosphonic acid compound; the composition comprises less than 500 ppm by weight of a tetraalkylammonium salt; and A composition, wherein the composition comprises 0.03 to 0.3 weight percent potassium bicarbonate.

3. The composition of claim 1, comprising 0.2 to 1.5 weight percent of said silica abrasive particles.

4. The composition of claim 1, comprising 0.1 to 0.5 weight percent of said polysilicon promoter.

5. The composition of claim 1 , wherein the heterocyclic amine is a triazole compound.

6. The composition of claim 1 wherein the aminophosphonic acid compound is aminotrimethylene phosphonic acid.

7. 10. The composition of claim 1 comprising 0.05 to 0.5 weight percent aminotrimethylene phosphonic acid, and wherein the polysilicon accelerator is arginine.

8. The composition of claim 1, comprising less than 10 ppm of a tetraalkylammonium salt.

9. 1. A method of chemical mechanical polishing a substrate comprising a polysilicon material, comprising: (a) an aqueous liquid carrier; 0.1 to 3 weight percent silica abrasive particles dispersed in said liquid carrier; 0.05 to 1 weight percent of a polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; alkali metal salts providing a polysilicon polishing composition comprising: the polysilicon polishing composition further comprising 0.01 to 1 weight percent of a potassium salt and 0.01 to 0.5 weight percent of a heterocyclic amine; the polysilicon polishing composition has a pH in the range of 10 to 11; the polysilicon polishing composition further comprising 0.05 to 0.5 weight percent of an aminophosphonic acid compound; the polysilicon polishing composition comprising less than 500 ppm by weight of a tetraalkylammonium salt; the polysilicon polishing composition comprising 0.03 to 0.3 weight percent potassium bicarbonate; (b) contacting the substrate with the polysilicon polishing composition; (c) moving the polysilicon polishing composition relative to the substrate; (d) abrading the substrate to remove a portion of the polysilicon material from the substrate, thereby polishing the substrate.

10. the substrate further comprises a silicon oxide material and a silicon nitride material; (d) wherein the removal rate selectivity of the polysilicon material to the silicon oxide material is 50:1 or greater; 10. The method of claim 9, wherein in (d) the removal rate selectivity of the polysilicon material to the silicon nitride material is 50:1 or greater.

11. the polysilicon polishing composition comprising 0.2 to 1.5 weight percent of the silica abrasive particles and 0.1 to 0.5 weight percent of the polysilicon accelerator; 10. The method of claim 9, wherein the polysilicon accelerator is a guanidine derivative.

12. 12. The method of claim 11, wherein the polysilicon polishing composition comprises 0.05 to 0.5 weight percent aminotrimethylene phosphonic acid and the polysilicon accelerator is arginine.

13. 10. The method of claim 9, wherein the polysilicon polishing composition comprises less than 10 ppm of a tetraalkylammonium salt.

14. 1. A method of chemical mechanical polishing a substrate comprising a polysilicon material, comprising: (a) an aqueous liquid carrier; 1 to 15 weight percent silica abrasive particles dispersed in said liquid carrier; 0.5 to 10 weight percent of a polysilicon accelerator selected from the group consisting of amino acids, guanidine derivatives, and mixtures thereof; an alkali metal salt; less than 0.1 weight percent of a tetraalkylammonium salt; providing a concentrated polysilicon polishing composition comprising: (b) adding 1 part of the concentrated polysilicon polishing composition to 5 to 30 parts of water to obtain a point-of-use polishing composition having a pH in the range of 10 to 11; the point-of-use polishing composition further comprises 0.01 to 1 weight percent of a potassium salt and 0.01 to 0.5 weight percent of a heterocyclic amine; the point-of-use polishing composition further comprising 0.05 to 0.5 weight percent of an aminophosphonic acid compound; the point-of-use polishing composition comprising 0.03 to 0.3 weight percent potassium bicarbonate; (c) moving the point-of-use polishing composition relative to the substrate; (d) abrading the substrate to remove a portion of the polysilicon material from the substrate, thereby polishing the substrate.

15. the substrate further comprises a silicon oxide material and a silicon nitride material; the polysilicon material:silicon oxide material removal rate selectivity is 50:1 or greater; 15. The method of claim 14, wherein the removal rate selectivity of the polysilicon material to the silicon nitride material is greater than or equal to 50:1.

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