Method for increasing the removal rate of polysilicon

Abstract

A method for increasing the removal rate of polysilicon from a substrate includes mixing an acidic chemical mechanical polishing slurry containing water, an organic acid, and an abrasive with an alkaline solution containing water, an abrasive, and a lower alkyl amine compound; providing a chemical mechanical polishing pad having a polishing surface; creating a dynamic contact at an interface between the polishing pad and the substrate; and dispensing the mixture of the chemical mechanical polishing slurry and the alkaline solution onto the polishing surface at or near the interface between the polishing pad and the substrate, wherein some of the polysilicon is polished away from the substrate.

Description

Invention Field

[0001] This invention relates to a method for increasing the removal rate of polysilicon from a substrate. More specifically, this invention relates to a method for increasing the removal rate of polysilicon from a substrate by: mixing an acidic chemical mechanical polishing slurry containing water, organic acid, and abrasive particles with an alkaline solution containing water and a lower alkyl chain amine compound; providing a chemical mechanical polishing pad having a polishing surface; creating dynamic contact at the interface between the polishing pad and the substrate; and dispensing the mixture of the chemical mechanical polishing slurry and the alkaline solution onto the polishing surface at or near the interface between the polishing pad and the substrate, wherein a portion of the polysilicon is polished away from the substrate. Background Technology

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

[0003] As material layers are deposited and removed sequentially, the uppermost surface of the wafer becomes non-planar. Because subsequent semiconductor processing (e.g., metallization) requires a flat surface on the wafer, wafer planarization is necessary. Planarization can be used to remove unwanted surface topography and surface defects, such as rough surfaces, aggregated material, lattice damage, scratches, and contaminated layers or materials.

[0004] Chemical mechanical planarization, or chemical mechanical polishing (CMP), is a common technique used to planarize substrates such as semiconductor wafers. In conventional CMP, the wafer is mounted on a carrier assembly and positioned to contact a polishing pad in the CMP apparatus. The carrier assembly applies controlled pressure to the wafer, pressing it against the polishing pad. The pad is moved relative to the wafer by an external driving force (e.g., rotation). Simultaneously, a polishing composition (“slurry”) or other polishing fluid is provided between the wafer and the polishing pad. Thus, the wafer surface is polished and planarized through the chemical and mechanical action of the pad surface and the slurry. However, CMP presents significant challenges. Each type of material requires a unique polishing composition, properly designed polishing pads, optimized process settings for both polishing and post-CMP cleaning, and other factors that must be tailored specifically for the application of the material being polished.

[0005] For example, acidic oxide slurries are increasingly being adapted for advanced technology nodes, such as 28 nm and below. The abrasives present in such slurries are positively charged through various chemical or additive methods. These slurries exhibit excellent defect rates and planarization efficiency (PE) performance, with a significantly lower point of use (POU) silica weight percentage than their basic counterparts.

[0006] Meanwhile, consumers have a strong desire to retain a consumable set that is universal for a variety of chemical mechanical polishing (CMP) compositions, including polysilicon CMP as disclosed in US 8,435,420. The CMP industry has found that polishing polysilicon with acidic oxide slurries exhibits better PE and fewer pits; however, a major drawback is the relatively low polysilicon removal rate. For example, aqueous slurries containing 1 wt%–2 wt% colloidal silica particles and having a pH less than 6 provide a polysilicon removal rate of approximately 1600 Å / min. Recently, in the CMP industry, there has been a need for higher polysilicon removal rates for thick polysilicon applications using acidic oxide slurries (where approximately 2–3 µm of polysilicon needs to be removed from the substrate).

[0007] Therefore, there is a need in the chemical mechanical polishing industry to provide a method to increase the removal rate of polycrystalline silicon from the substrate. Summary of the Invention

[0008] This invention relates to a method for chemically and mechanically polishing polycrystalline silicon, comprising: Provides a substrate containing polycrystalline silicon; Provide an acidic chemical mechanical polishing slurry composed of the following: water; Abrasive particles; Organic acids; Compounds that optionally contain two quaternary ammonium groups; Optional biocides; and Provide an alkaline solution consisting of the following: water; Amine compounds having the following formula: (I) R1 and R2 are independently selected from C1-C4 alkyl groups and R' is a C1-C4 alkylene group; Optional biocides; and The acidic chemical mechanical polishing slurry is mixed with the alkaline solution to form an alkaline chemical mechanical polishing slurry comprising the water, the abrasive particles, the organic acid, the amine compound, and optionally the biocide; optionally, the compound containing two quaternary ammonium groups; and Provide chemical mechanical polishing pads with polished surfaces; Dynamic contact is generated at the interface between the chemical mechanical polishing pad and the substrate; and The alkaline chemical mechanical polishing slurry is applied to the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate to remove at least some of the polycrystalline silicon.

[0009] The present invention further relates to a method for chemical mechanical polishing of polycrystalline silicon, comprising: Provides a substrate containing polycrystalline silicon; Provide an acidic chemical mechanical polishing slurry composed of the following: water; Abrasive particles; Organic acids; Compounds that optionally contain two quaternary ammonium groups; Optional biocides; and The pH of the acidic chemical mechanical polishing slurry is less than 6; Provide an alkaline solution consisting of the following: water; Amine compounds selected from the group consisting of: 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, N,N-diethylenediamine, N,N-di-n-butylethylenediamine, 3-(dimethylamino)-1-propylamine, N-isopropyl-1,3-dipropanediamine, 2-dimethylamino-2-propylamine, and mixtures thereof; Optional biocides; and The alkaline chemical mechanical polishing solution has a pH greater than 7; and The acidic chemical mechanical polishing slurry is mixed with the alkaline solution to form an alkaline chemical mechanical polishing slurry comprising the water, the abrasive particles, the organic acid, the amine compound, optionally the compound containing two quaternary ammonium groups, and optionally the biocide; and The alkaline chemical mechanical polishing slurry has a pH greater than 7; Provide chemical mechanical polishing pads with polished surfaces; Dynamic contact is generated at the interface between the chemical mechanical polishing pad and the substrate; and The alkaline chemical mechanical polishing slurry is applied to the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate to remove at least some of the polycrystalline silicon.

[0010] The chemical mechanical polishing method of this invention can improve the polysilicon removal rate, reduce the static etching rate, and provide a smooth polished polysilicon surface. The method of this invention also selectively polishes polysilicon on TEOS. Detailed Implementation

[0011] As used throughout this specification, unless the context otherwise indicates, the following abbreviations have the following meanings: mL = milliliter; µ = µm = micrometer; kPa = kilopascal; Å = angstrom; DI = deionized; ppm = parts per million = mg / L; 1wt% = 10,000 ppm; mm = millimeter; cm = centimeter; min = minute; rpm = revolutions per minute; lbs = pound; kg = kilogram; 2.54 cm = inch; Poly-Si = polycrystalline silicon; DLS = dynamic light scattering; wt% = weight percentage; RR = removal rate; S = slurry; PS = polishing slurry of the present invention; CS = control slurry; ES = etching solution of the present invention; CES = contrast etching solution; POU = point of use; EDA = ethylenediamine; PEI = polyethyleneimine; DEAMS = (N,N-Diethylaminomethyl)triethoxysilane, 98% (Gelest Inc., Morrisville, PA); TMOS = tetramethyl orthosilicate; TMAH = tetramethylammonium hydroxide; TEA = tetraethylammonium; TEAH = tetraethylammonium hydroxide; diquat = N,N,N,N',N'N'-hexabutyl-1,4-butanediammonium hydroxide; and SiN = silicon nitride.

[0012] The terms "chemical mechanical polishing" or "CMP" refer to a process that polishes a substrate solely by chemical and mechanical forces, and are distinguished from electrochemical-mechanical polishing (ECMP), in which an electrical bias is applied to the substrate. The term "slurry" refers to a mixture of solids suspended in water with a density greater than that of water. The term "solution" refers to a mixture in which a minor component (solute) is substantially homogeneously dissolved in a major component (solvent), where the solvent is water. The term "chempack" refers to an alkaline aqueous solution containing one or more lower alkylamine compounds. The term "polycrystalline silicon" refers to polycrystalline silicon or multicrystalline silicon. The term "TEOS" refers to silicon dioxide formed by the decomposition of tetraethyl orthosilicate (Si(OC2H5)4). The term "alkylene" refers to a divalent saturated aliphatic group or portion that is thought to be derived from alkenes, such as ethylene:-CH2-CH2- or methylene:-CH2-, by opening a double bond, or from alkanes by removing two hydrogen atoms from different carbon atoms. The term "alkyl" refers to an organic group having the following general formula: C n H 2n+1Where “n” is an integer, and the suffix “base” refers to a fragment of an alkane formed by removing hydrogen. The term “planar” means a substantially flat surface or flat morphology having both length and width dimensions. Throughout this specification, the terms “composition” and “slurry” are used interchangeably. The term “a / an” refers to both the singular and plural. KLEBOSOL™ particles (manufactured by AZ Electronic Materials and available from The DuPont Electronics, Inc.), such as KLEBOSOL™ 1598-B25 particles, are prepared by the water glass method. Unless otherwise stated, all percentages are by weight. All numerical ranges are inclusive and can be combined in any order, except where it is logical to limit the numerical range to a maximum sum of 100%.

[0013] The method for polishing a polycrystalline silicon substrate according to the present invention includes providing an acidic chemical mechanical polishing slurry composed of water, abrasive particles, an organic acid, a compound optionally containing two quaternary ammonium groups, and optionally a biocide; and providing an amine compound having the following formula: (I) R1 and R2 are independently selected from C1-C4 alkyl groups and R' is a C1-C4 alkylene group and optionally a biocide; and an acidic chemimechanical polishing slurry is mixed with the aqueous alkaline solution to form an alkaline chemimechanical polishing slurry consisting of water, abrasive particles, organic acid, amine compound, optionally a biocide and optionally a compound containing two quaternary ammonium groups.

[0014] Preferably, in the method of chemical mechanical polishing of a substrate comprising polycrystalline silicon, the water contained in the provided chemical mechanical polishing slurry and solution is at least one of deionized water and distilled water to limit incidental impurities.

[0015] Preferably, the abrasive used in the chemical mechanical polishing slurry is selected from the group consisting of inorganic oxides, inorganic hydroxides, inorganic hydroxide oxides, metal borides, metal carbides, metal nitrides, and mixtures comprising at least one of the foregoing. Suitable inorganic oxides include, for example, silicon dioxide (SiO2), aluminum oxide (Al2O3), zirconium oxide (ZrO2), cerium dioxide (CeO2), manganese oxide (MnO2), titanium oxide (TiO2), or combinations comprising at least one of the foregoing oxides. If desired, modified forms of these inorganic oxides, such as inorganic coated particles, may also be used. Suitable metal carbides, borides, and nitrides include, for example, silicon carbide, silicon nitride, silicon carbonitride (SiCN), boron carbide, tungsten carbide, zirconium carbide, aluminum boride, tantalum carbide, titanium carbide, or combinations comprising at least one of the foregoing metal carbides, borides, and nitrides. More preferably, the abrasive is colloidal silica abrasive. Preferably, the colloidal silica abrasive contains at least one of fumed silica, precipitated silica, and agglomerated silica.

[0016] Preferably, the abrasive used in the chemical mechanical polishing composition of the present invention has < An average particle size of 100 nm (more preferably, 1 nm to 100 nm). More preferably, the abrasive used in the chemical mechanical polishing composition of the present invention has a particle size as measured by dynamic light scattering (DLS) technology. < Colloidal silica abrasive with an average particle size of 100 nm (preferably, 1 nm to 100 nm; more preferably, 10 nm to 80 nm; even more preferably, 20 nm to 80 nm; most preferably, 60 nm to 30 nm).

[0017] Most preferably, in the method for polishing the substrate of the present invention, the colloidal silica abrasive particles are colloidal silica abrasive particles prepared by the water glass method. An example of commercially available colloidal silica abrasive particles prepared by the water glass method is KLEBOSOL™ 1598-B25 slurry (manufactured by AZ Electronic Materials and available from The DuPont Electronics, Inc.). Such colloidal silica abrasives can be mixed with nitrogen-containing silane compounds. An example of such a mixture is KLEBOSOL™ 1598-B25 slurry (manufactured by AZ Electronic Materials and available from The DuPont Electronics, Inc.) plus (0.01 wt%-0.02 wt% DEAMS to 1 wt% silica).

[0018] Optionally, but preferably, the aqueous acidic abrasive slurry includes a compound containing two quaternary ammonium groups, such as N,N,N,N',N',N'-hexylbutyl-1,4-butanediammonium hydroxide (HBBAH). Such compounds are included in the aqueous acidic slurry to enhance slurry stabilization during storage, transportation, and thermal aging, while maintaining a high polysilicon removal rate. These compounds are included in the aqueous acidic abrasive slurry in conventional amounts, preferably 1-100 ppm, more preferably 5-50 ppm POU.

[0019] Additional nitrogen-containing compounds that may be included in the chemical mechanical polishing compositions of the present invention are amino acids having one to eight carbon atoms, such as lysine, glutamine, glycine, iminodiacetic acid, alanine, valine, leucine, isoleucine, serine, and threonine.

[0020] Preferably, the chemical mechanical polishing slurry contains no more than 6 wt% abrasive particles, more preferably 0.01 wt% to 5 wt%, even more preferably 0.05 wt% to 3 wt%, even more preferably 1 wt% to 3 wt%, and still more preferably 1 wt% to 2 wt% abrasive particles.

[0021] The aqueous acidic slurry in the method of the present invention comprises one or more organic acids to provide a pH of less than 6, preferably 3-5, more preferably 4-5. The organic acids include, but are not limited to, dicarboxylic acids, wherein the dicarboxylic acids include, but are not limited to, oxalic acid, succinic acid, adipic acid, maleic acid, malic acid, glutaric acid, tartaric acid, their salts, or mixtures thereof. More preferably, the chemical mechanical polishing slurry contains a dicarboxylic acid, wherein the dicarboxylic acid is selected from the group consisting of oxalic acid, succinic acid, tartaric acid, their salts, and mixtures thereof. Even more preferably, the dicarboxylic acid is selected from the group consisting of oxalic acid, succinic acid, their salts, and mixtures thereof. Most preferably, the dicarboxylic acid is succinic acid or a salt thereof.

[0022] Acidic chemimechanical polishing slurries may contain 1 ppm to 2,600 ppm, preferably 100 ppm to 1,400 ppm, more preferably 100 ppm to 1,350 ppm, and even more preferably 100 ppm to 1,000 ppm of organic acids, such as dicarboxylic acids, including but not limited to oxalic acid, succinic acid, adipic acid, maleic acid, malic acid, glutaric acid, tartaric acid, their salts, or mixtures thereof.

[0023] The amount of amine compound contained in the chempack or aqueous alkaline solution is 10 ppm to 10,000 ppm, preferably 50 ppm to 5,000 ppm, more preferably 100 ppm to 5,000 ppm, and most preferably 100 ppm to 2,500 ppm.

[0024] Preferably, the amine compound is selected from the group consisting of 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, N,N-diethylenediamine, N,N-di-n-butylethylenediamine, 3-(dimethylamino)-1-propylamine, N-isopropyl-1,3-dipropanediamine, 2-dimethylamino-2-propylamine, and mixtures thereof. More preferably, the amine compound is selected from the group consisting of 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, and mixtures thereof. Most preferably, the amine compound is 3-(diethylamino)propylamine.

[0025] In the method for polishing a polycrystalline silicon substrate according to the present invention, the aqueous alkaline solution containing amine has a pH greater than 7. Preferably, the aqueous alkaline solution has a pH greater than 7-13. More preferably, the aqueous alkaline solution has a pH of 8-12. Even more preferably, the aqueous alkaline solution has a pH of 10-12; and most preferably a pH of 10-11.5, such as 10.5-11.5 is a very preferred range.

[0026] Optionally, the chemical mechanical polishing slurries and solutions may contain biocides such as KORDEX™ MLX (9.5 wt% - 9.9 wt% methyl-4-isothiazolin-3-one, 89.1 wt% - 89.5 wt% water, and ≤ 1.0% of related reaction products) or KATHON™ ICP III containing the active ingredients 2-methyl-4-isothiazolin-3-one and 5-chloro-2-methyl-4-isothiazolin-3-one, each manufactured by Dow Chemical Company (KATHON™ and KORDEX™ are trademarks of DuPont Electronics, Inc.). Such biocides may be included in the chemical mechanical polishing slurries and solutions of the present invention in conventional amounts as known to those skilled in the art.

[0027] Aqueous acidic slurries and aqueous alkaline solutions can be mixed together using any conventional method known in the art to form an aqueous alkaline chemical mechanical polishing slurry. Typically, an adjustable-speed magnetic mixer can be used to mix the acidic slurry and alkaline solution. Mixing is carried out at room temperature. The acidic slurry and alkaline solution are mixed at a weight ratio of 1:100 to 100:1, preferably 1:7 to 7:1, more preferably 1:3 to 3:1, and most preferably 1:1. Mixing can be carried out on the polishing machine platen or before the acidic slurry and alkaline solution are applied to the polishing machine platen.

[0028] The mixed acidic slurry and chempack or aqueous alkaline solution form an aqueous alkaline chemical mechanical polishing slurry with a pH greater than 7. Due to the lower-chain alkylamines, the mixing of the acidic slurry with the chempack raises the mixture to an alkaline pH. The relatively rapid increase in pH of the acidic slurry during the mixing process prevents abrasive particle agglomeration. Preferably, the aqueous alkaline chemical mechanical polishing slurry has a pH greater than 7-13, more preferably, it has a pH of 8-12, even more preferably, it has a pH of 10-12; and most preferably, it has a pH of 10-11.5, such as 10.5-11.5 being a very preferred range.

[0029] Preferably, the aqueous alkaline chemical mechanical polishing slurry of the present invention comprises water, abrasive particles, organic acid, and an amine compound having the following formula: (I) R1 and R2 are independently selected from C1-C4 alkyl groups and R' is a C1-C4 alkylene group, optionally containing two quaternary ammonium groups and optionally a biocide, wherein the aqueous alkaline chemimechanical polishing slurry has a pH greater than 10.

[0030] Preferably, the amine compound in the aqueous alkaline chemical mechanical polishing slurry of the present invention is selected from the group consisting of 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, N,N-diethylenediamine, N,N-di-n-butylethylenediamine, 3-(dimethylamino)-1-propylamine, N-isopropyl-1,3-dipropanediamine, 2-dimethylamino-2-propylamine, and mixtures thereof. More preferably, the amine compound is selected from the group consisting of 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, and mixtures thereof. Most preferably, the amine compound in the aqueous alkaline chemical mechanical polishing slurry of the present invention is 3-(diethylamino)propylamine.

[0031] Preferably, the aqueous alkaline chemical mechanical polishing slurry contains no more than 6 wt% abrasive particles, more preferably 0.01 wt%-5 wt%, even more preferably 0.05 wt%-3 wt%, even more preferably 1 wt%-3 wt%, and still more preferably 1 wt%-2 wt% abrasive particles.

[0032] Aqueous alkaline chemimechanical polishing slurries may contain 1 ppm to 2,600 ppm, preferably 100 ppm to 1,400 ppm, more preferably 100 ppm to 1,350 ppm, and even more preferably 100 ppm to 1,000 ppm of organic acid. Preferably, the organic acid is a dicarboxylic acid.

[0033] These amines are included in the aqueous alkaline chemimechanical polishing slurry in amounts of 25 ppm to 10,000 ppm, preferably 50 ppm to 10,000 ppm, more preferably 50 ppm to 5,000 ppm, and most preferably 100 ppm to 2,500 ppm.

[0034] Optionally, but preferably, the aqueous alkaline chemical mechanical polishing slurry of the present invention comprises a compound containing two quaternary ammonium groups as described.

[0035] The biocides described above can be included in the aqueous alkaline chemimechanical slurry of the present invention in conventional amounts known to those skilled in the art.

[0036] More preferably, the aqueous alkaline chemical mechanical polishing slurry of the present invention comprises water, 1 wt%-3 wt% abrasive particles, 100 ppm-1,350 ppm dicarboxylic acid, and 50 ppm-5000 ppm amine compounds having the following formula: (I) R1 and R2 are independently selected from C1-C4 alkyl groups and R' is a C1-C4 alkylene group, optionally containing two quaternary ammonium groups and optionally a biocide, wherein the aqueous alkaline chemimechanical polishing slurry has a pH greater than 10 to 11.5.

[0037] Even more preferably, the aqueous alkaline chemical mechanical polishing slurry of the present invention comprises water, 1 wt%-2 wt% abrasive particles, 100 ppm-1000 ppm dicarboxylic acid, and 100 ppm-2500 ppm amine compounds selected from the group consisting of: 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, N,N-diethylenediamine, N,N-di-n-butylethylenediamine, 3-(dimethylamino)-1-propylamine, N-isopropyl-1,3-dipropanediamine, 2-dimethylamino-2-propylamine, and mixtures thereof. More preferably, the amine compounds are selected from the group consisting of 3-(diethylamino)propylamine, N,N-dimethylethylenediamine, mixtures thereof, compounds optionally containing two quaternary ammonium groups, and optionally biocides, wherein the pH of the aqueous alkaline chemical mechanical polishing slurry is 10.5-11.5.

[0038] Preferably, the provided substrate is a semiconductor substrate comprising polysilicon and a dielectric such as TEOS or SiN; more preferably, the substrate is a semiconductor comprising polysilicon and TEOS.

[0039] Preferably, in the method for polishing the substrate of the present invention, the provided chemical mechanical polishing pad can be any suitable polishing pad known in the art. Those skilled in the art know how to select a suitable chemical mechanical polishing pad for use in the method of the present invention. More preferably, in the method for polishing the substrate of the present invention, the provided chemical mechanical polishing pad is selected from woven polishing pads and nonwoven polishing pads. Even more preferably, in the method for polishing the substrate of the present invention, the provided chemical mechanical polishing pad comprises a polyurethane polishing layer. Most preferably, in the method for polishing the substrate of the present invention, the provided chemical mechanical polishing pad comprises a polyurethane polishing layer containing hollow polymer particles and a polyurethane-impregnated nonwoven sub-pad. Preferably, the provided chemical mechanical polishing pad has at least one groove on the polishing surface.

[0040] Preferably, in the method for polishing the substrate of the present invention, the provided chemical mechanical polishing composition is dispensed onto the polishing surface of the provided chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate.

[0041] Preferably, in the method for polishing the substrate of the present invention, a downward pressure of 0.69 kPa to 34.5 kPa perpendicular to the surface of the substrate being polished is used to generate dynamic contact at the interface between the provided chemical mechanical polishing pad and the substrate.

[0042] In the method for polishing a polysilicon-containing substrate of the present invention, the provided chemical mechanical polishing composition, under the conditions of a platen speed of 93-123 rpm, a carriage speed of 87-117 rpm, a chemical mechanical polishing composition flow rate of 40-300 mL / min, and a nominal downpressure of 21.4-24.1 kPa on a 300 mm polishing machine, has a polysilicon removal rate of ≥ 500 Å / min; preferably, ≥ 700 Å / min; more preferably, ≥ 1,000 Å / min; further preferably, ≥ 1200 Å / min; and even more preferably, > A polycrystalline silicon removal rate of 2000 Å / min; and wherein the chemical mechanical polishing pad comprises a polyurethane polishing layer containing polymer hollow microparticles and a polyurethane-impregnated nonwoven sub-pad.

[0043] The following examples are intended to illustrate the invention, but are not intended to limit the scope of the invention.

[0044] Example 1

[0045] Slurry formulation

[0046] The aqueous acidic chemical mechanical polishing slurry of this example was prepared by mixing KLEBOSOL™ 1598-B25 or KLEBOSOL™ 1598-B25 with an abrasive (0.01-0.02 wt% DEAMS to 1 wt% silica) and water at room temperature. Mixing was performed using a standard laboratory magnetic mixer. The pH was adjusted with succinic acid or nitric acid.

[0047] Table 1

[0048] 1 N,N,N,N',N',N'-hexylbutyl-1,4-butane diammonium hydroxide (HBBAH).

[0049] Example 2

[0050] The chemical mechanical polishing slurry of the present invention

[0051] The chemical mechanical polishing composition of the present invention is prepared as shown in the table below. An amine is mixed with the slurry of Example 1 above. These components are mixed at room temperature.

[0052] Table 2

[0053] Example 3

[0054] Comparison of chemical mechanical polishing slurries

[0055] The comparative chemical mechanical polishing composition is prepared as shown in the table below. The amine is mixed with the slurry from Example 1 above. These components are mixed at room temperature.

[0056] Table 3

[0057] Example 4

[0058] Polysilicon and TEOS removal rates

[0059] Polishing experiments were conducted on 20.32 cm (8-inch) square blanket wafers mounted on a Strasbaugh 6EC polisher using the polishing slurries listed in Tables 2 and 3 above. Polishing removal rate experiments were performed on 20.32 cm square 15 kÅ thick TEOS sheet wafers from Novellus and polycrystalline silicon blanket wafers from WaferNet Inc., Silicon Valley Microelectronics, or SKW Associates, Inc. All polishing experiments were conducted using IC1010 polyurethane polishing pads paired with SP2310 subpads (commercially available from Rohm and Haas Electronic Materials CMP Inc.) at a typical downforce of 21.4 kPa (3.1 psi), a chemical mechanical polishing composition flow rate of 150 mL / min, a stage rotation speed of 93 rpm, and a carriage rotation speed of 87 rpm. The polishing pad was dressed using a Kinik PDA33A-3 diamond pad conditioner (commercially available from China Grinding Wheel Co., Ltd., Taiwan). The polishing pad was dressed with the conditioner at 80 rpm (platen) / 36 rpm (conditioner) using a downforce of 9 lbs (4.1 kg) for 15 minutes and then at a downforce of 7 lbs (3.2 kg) for 15 minutes. Further off-site conditioning of the polishing pad was performed before polishing using a downforce of 7 lbs (3.2 kg) for 24 seconds. The polysilicon and TEOS removal rates were determined using a KLA ASET F5X metering tool.

[0060] Table 4

[0061] Example 5

[0062] Polysilicon static etching rate

[0063] The aqueous etching solutions are listed in Table 5 below. The aqueous solutions contain 2500 ppm amine and have no pH adjustment. CES1 consists only of water and sufficient succinic acid to maintain pH = 4.44. Static etching tests were performed by immersing a polycrystalline silicon blanket-coated wafer (20 cm in diameter) in 2000 g of sample. After 30 min, the polycrystalline silicon wafer was removed from the test solution. The thickness of the polycrystalline silicon film before and after etching was measured using a KLA SpectralFX200 metrology tool. The total removal was determined by subtracting the post-etched thickness (measured at 49 points on the wafer) from the pre-etched thickness. The static etching rate (Å / min) was then calculated from the total removal (Å / 30 min). The standard deviation was calculated from the 49-point values ​​of the etching rate on the wafer, reflecting the uniformity of etching.

[0064] Table 5

[0065] ES1 and CES1 yielded the best results, with wafers appearing smooth and clean without any observable surface roughness. In contrast, CES2 and CES3 exhibited substantially observable roughness on their surfaces. CES4 showed some observable surface roughness, and CES5 had a poor-looking surface with significant roughness.

[0066] Example 6

[0067] Static etching rate of polycrystalline silicon with N,N-dimethylethylenediamine and ethylenediamine

[0068] The aqueous solution contains 2500 ppm N,N-dimethylethylenediamine or ethylenediamine. The solution was left as is without any pH adjustment.

[0069] Static etching tests were performed by immersing a polycrystalline silicon blanket-coated wafer (20 cm in diameter) in a 2000 g sample. The wafer was removed from the test solution after 30 min. The total removal was determined by subtracting the post-etched thickness (measured at 49 points on the wafer) from the pre-etched thickness. The static etching rate (Å / min) was then calculated from the total removal (Å / 30 min). The standard deviation was calculated from the 49-point values ​​of the etching rate on the wafer, reflecting the uniformity of etching.

[0070] Table 6

[0071] Compared to CES6, ES2 shows a significant reduction in the static etching rate of polysilicon.

Claims

1. A method for chemically and mechanically polishing polycrystalline silicon, comprising: Provides a substrate containing polycrystalline silicon; Provide an acidic chemical mechanical polishing slurry composed of the following: water; Abrasive particles; Organic acids; Compounds that optionally contain two quaternary ammonium groups; Optional biocides; and Provide an alkaline solution consisting of the following: water; Amine compounds having the following formula: (I) R1 and R2 are independently selected from C1-C4 alkyl groups and R' is a C1-C4 alkylene group; Optional biocides; The amine compound is selected from the group consisting of 3-(diethylamino)propylamine, N,N-diethylethylenediamine, N,N-di-n-butylethylenediamine, 3-(dimethylamino)-1-propylamine, 2-dimethylamino-2-propylamine, and mixtures thereof; and The acidic chemical mechanical polishing slurry is mixed with the alkaline solution to form an alkaline chemical mechanical polishing slurry consisting of the water, the abrasive particles, the organic acid, the amine compound, and optionally the biocide; optionally, the compound containing two quaternary ammonium groups. as well as Provide chemical mechanical polishing pads with polished surfaces; Dynamic contact is generated at the interface between the chemical mechanical polishing pad and the substrate; as well as The alkaline chemical mechanical polishing slurry is applied to the polishing surface of the chemical mechanical polishing pad at or near the interface between the chemical mechanical polishing pad and the substrate to remove at least some of the polycrystalline silicon.

2. The method as described in claim 1, wherein, The abrasive particles are selected from the group consisting of inorganic oxides, inorganic hydroxides, inorganic hydroxide oxides, metal borides, metal carbides, metal nitrides, and mixtures thereof.

3. The method as described in claim 1, wherein, The amine compound is 3-(dimethylamino)-1-propylamine.

4. The method of claim 1, wherein, The organic acid is a dicarboxylic acid.

5. The method of claim 4, wherein, The dicarboxylic acid is selected from the group consisting of oxalic acid, succinic acid, adipic acid, maleic acid, malic acid, glutaric acid, tartaric acid, their salts, and mixtures thereof.

6. The method of claim 1, wherein, The pH of the acidic chemical mechanical polishing slurry is less than 6.

7. The method of claim 1, wherein, The alkaline chemical mechanical polishing slurry has a pH greater than 7.

8. The method of claim 1, wherein, The alkaline chemical mechanical polishing slurry exhibits a polycrystalline silicon removal rate of ≥ 500 Å / min under the following conditions: a platen speed of 93-123 rpm, a carriage speed of 87-117 rpm, a chemical mechanical polishing slurry flow rate of 125-300 mL / min, and a nominal downpressure of 21.4-24.1 kPa on a 200 mm polishing machine; and wherein the chemical mechanical polishing pad comprises a polyurethane polishing layer containing polymer hollow microparticles and a polyurethane-impregnated nonwoven sub-pad.

9. A chemical mechanical polishing composition comprising the following: water; Abrasive particles; Amine compounds having the following formula: (I) Organic acids, The amine compound is selected from the group consisting of 3-(diethylamino)propylamine, N,N-diethylethylenediamine, N,N-di-n-butylethylenediamine, 3-(dimethylamino)-1-propylamine, 2-dimethylamino-2-propylamine and mixtures thereof; Compounds that optionally contain two quaternary ammonium groups; Optional biocides; and The pH value is greater than 10.

10. The chemical mechanical polishing composition of claim 9, wherein, The amine compound is 3-(dimethylamino)-1-propylamine.

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