Silicon wafer polishing composition and preparation process thereof

Abstract

The invention discloses a silicon wafer polishing composition and application thereof. The silicon wafer polishing composition comprises silicon dioxide hydrosol subjected to special treatment, organic alkali, a pH regulator, an anionic water-soluble polymer and water. According to the silicon wafer polishing composition, the conventional alkaline silica sol is subjected to special treatment, particle residues on the surface of the polished silicon wafer can be greatly reduced, and compared with the prior art, the silicon wafer polishing composition has remarkable advantages.

Description

Technical Field

[0001] The invention relates to the technical field of chemical mechanical polishing, and in particular to a silicon wafer polishing composition and a preparation process thereof. Background Art

[0002] Chemical mechanical polishing (CMP) of silicon wafers generally uses alkaline silica polishing liquid, which uses the chemical corrosion reaction between alkali and silicon to generate soluble silicates, and then polishes and removes the reaction products in time through the adsorption of small, soft, large specific surface area, negatively charged SiO2 particles and the mechanical friction between the polishing pad and the silicon wafer, thereby achieving the purpose of removing the damaged layer and contaminants on the surface of the wafer. As the process nodes of integrated circuits become smaller and smaller, the requirements for substrate wafers are also getting higher and higher. In order to improve the surface quality of silicon wafers and reduce the residual particles on the surface of silicon wafers, silicon wafer CMP generally needs to be processed in three steps, namely rough polishing, medium polishing, and fine polishing. Medium polishing is the second step of CMP, and its CMP performance directly affects the surface condition after fine polishing.

[0003] Particle residue is an extremely critical indicator before silicon wafers are shipped. Rough polishing liquid mainly relies on corroding silicon wafers to achieve the effect of rapid removal. The surface roughness of silicon wafers after rough polishing is large and the corrosion residue is high. It is difficult to achieve high polishing rate and surface quality in rough polishing. The removal rate of fine polishing is extremely low, generally less than 0.1μm / min. It takes a lot of time and consumables cost to repair the surface of silicon wafers after rough polishing only through fine polishing. Therefore, medium polishing plays a vital role in silicon wafer polishing. How to repair the surface of silicon wafers to the greatest extent during medium polishing, reduce the particle residue on the surface of silicon wafers, and avoid pressure on fine polishing are issues worth studying and discussing for medium polishing liquid.

[0004] At present, there is little research on silicon wafer intermediate polishing liquid in China. Some substrate manufacturers use it as intermediate polishing liquid by increasing the dilution ratio of coarse polishing liquid. The disadvantage of this method is that the coarse polishing liquid will still cause corrosion and particle residue on the surface of the silicon wafer during the intermediate polishing CMP process. Since the corrosion of the coarse polishing liquid is more severe, this corrosion residue cannot be completely removed during the fine polishing process. Therefore, there is still a need for a silicon wafer intermediate polishing liquid that can reduce the particle residue on the surface of the silicon wafer while repairing the silicon wafer surface. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a silicon wafer polishing composition, which can greatly reduce the surface particle residue of the silicon wafer after polishing by adding specially treated silica hydrosol, organic base, anionic water-soluble polymer and water.

[0006] Another object of the present invention is to provide application of the silicon wafer polishing composition.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solution:

[0008] A silicon wafer polishing composition comprises a specially treated silica hydrosol, an organic base, an anionic water-soluble polymer and water;

[0009] The specially treated silica hydrosol is prepared by the following steps:

[0010] 1) adding an organic acid solution to the silica hydrosol, adjusting the pH value of the silica sol to between 2.0 and 7.0, and stirring and mixing to obtain a dispersion A;

[0011] 2) Adding an organic siloxane compound and an anionic surfactant to the dispersion A in sequence, stirring and mixing them evenly, to obtain a specially treated silica hydrosol.

[0012] In a specific embodiment, the mass percentage of each component used in the preparation process of the specially treated silica hydrosol is:

[0013]

[0014] In a specific embodiment, the silica hydrosol has a particle size of 30-120 nm and a solid content of 10-50 wt%.

[0015] In a specific embodiment, the organic acid solution is a mixture of an organic acid and its derivatives and water, and the mass concentration of the organic acid and its derivatives in the organic acid solution is 0.1-50%, preferably 1%-10%;

[0016] Preferably, the organic acid and its derivatives are selected from at least any one of formic acid, acetic acid, propionic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, oxalic acid, succinic acid, malic acid, gluconic acid, alanine, glycine, lactic acid, trifluoroacetic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, propylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid or their salts, preferably any one of oxalic acid, malonic acid, acetic acid and citric acid.

[0017] In a specific embodiment, the end groups of the organosiloxane compound do not contain cationic groups that can provide protons;

[0018] Preferably, the organosiloxane compound is selected from phenyltrimethoxysilane, vinyl triethoxysilane, 3-chloropropyl triethoxysilane, methyl trimethoxysilane, 1,1,3,3-tetramethyl disiloxane, 3-(2,3-epoxypropyloxy)propyl trimethoxysilane, 2-trimethylsiloxy-1,3-butadiene bistrimethylsiloxymethylsilane, tetrapropoxysilane, triethoxysilane, 1,2-bis(trimethylsiloxy)ethane, 3-chloropropyl methyl dimethoxysilane, triethylsilyl trifluoromethanesulfonate, 5-trifluoromethyl-2,4-bistrimethylsiloxypyrimidine, 1,7-divinyl-octamethyltetrasiloxane, 1,1,3,3-tetramethyl At least one of 1,3-disiloxanediol, bis-3-methacryloxypropylated tetramethyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethoxydisiloxane, etherified product of polyethylene glycol monomethyl ether, 1-trimethylsilyloxy-3-trimethylsilyl-2-propynyl bis-3-methacryloxypropylated tetramethyldisiloxane, 1,3-dimethoxy-1,1,3,3-tetramethyldisiloxane, 2-(tert-butyldiphenylsilyloxy)ethanol 4-((tert-butyldimethylsilyloxy)methyl)aniline, 1,5-divinyl-hexamethyltrisiloxane, and 1,3-bis(3-methacryloxypropyl)tetrakis(trimethylsilyloxy)disiloxane.

[0019] In a specific embodiment, the anionic surfactant is selected from fatty acid salts, sulfonates, sulfate esters and phosphate esters;

[0020] Preferably, the anionic surfactant is selected from the group consisting of decanylbenzene sulfonic acid, undecylbenzene sulfonic acid, dodecylbenzene sulfonic acid, hexadecylbenzene sulfonic acid, octadecylbenzene sulfonic acid, decanyl sulfonic acid, undecyl sulfonic acid, dodecyl sulfonic acid, hexadecyl sulfonic acid, octadecyl sulfonic acid, succinic acid monooctadecylamide sulfonic acid, dodecyl diphenyl ether disulfonic acid, allyloxy hydroxypropane sulfonic acid, methacrylic acid hydroxypropane sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, decanyl sulfuric acid, undecyl sulfuric acid, dodecyl sulfuric acid, hexadecyl sulfuric acid, octadecyl sulfuric acid, decanyl polyoxyethylene ether sulfuric acid Acid, undecyl polyoxyethylene ether sulfuric acid, dodecyl polyoxyethylene ether sulfuric acid, hexadecyl polyoxyethylene ether sulfuric acid, octadecyl polyoxyethylene ether sulfuric acid, isomeric tridecanol polyoxyethylene ether sulfuric acid, dodecyl polyoxyethylene ether carboxylic acid, undecyl polyoxyethylene ether carboxylic acid, dodecyl polyoxyethylene ether carboxylic acid, hexadecyl polyoxyethylene ether carboxylic acid, octadecyl polyoxyethylene ether carboxylic acid, methylene bisnaphthalene sulfonic acid, oleoyl methyl taurine, allyloxy nonylphenol polyoxyethylene ether monophosphate, isotridecanol ether phosphate, lauryl phosphate and their salts; preferably dodecylbenzene sulfonic acid.

[0021] In a specific embodiment, based on the total mass of the polishing composition, the following components are included in weight percentage:

[0022] Specially treated silica hydrosol 5%-80%; preferably 10%-40%;

[0023] Organic base 0.5%-10%; preferably 1%-5%;

[0024] Anionic water-soluble polymer 0.01%-1%; preferably 0.1%-1%;

[0025] The balance is water;

[0026] Preferably, a pH adjuster is also added to control the pH value of the polishing composition between 9.5 and 11.5;

[0027] More preferably, the pH regulator is selected from the group consisting of hydrogen chloride, nitric acid, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide, imidazole, N-methylimidazole, 1,2,4-triazole, tetramethylguanidine, formic acid, acetic acid, propionic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, oxalic acid, succinic acid, malic acid, gluconic acid, alanine, glycine, lactic acid, trifluoroacetic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenediamine, propylenediaminetetraacetic acid , hydroxyethylethylenediamine, hydroxyethylethylenediaminetriacetic acid, pyrophosphoric acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene 1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid or their salts, preferably any one of oxalic acid, hydrogen chloride, potassium hydroxide and tetramethylammonium hydroxide; more preferably potassium hydroxide or citric acid.

[0028] In a specific embodiment, the organic base is selected from at least one of methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, propylenediamine, butylenediamine, hydroxyethylethylenediamine, diethylenetriamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, trihexyltetramine, 1-(2-aminoethyl)piperazine, N-methylpiperazine, piperazine, imidazole, methylimidazole, 1,2,4-triazole, 4-amino-1,2,4-triazole, guanidine carbonate, guanidine hydrochloride, guanidine nitrate, tetramethylammonium hydroxide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium fluoride, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium fluoride; preferably tetramethylammonium hydroxide.

[0029] In a specific embodiment, the anionic water-soluble polymer is selected from at least one of polyacrylic acid, polymethacrylic acid, anionic polyacrylamide, polyethylene sulfonic acid, polypropylene sulfonic acid, polystyrene sulfonic acid and salts thereof;

[0030] Preferably, the weight average molecular weight of the anionic water-soluble polymer is 2000-10000000.

[0031] On the other hand, the aforementioned silicon wafer polishing composition is used in chemical mechanical polishing of silicon wafers.

[0032] Compared with the prior art, the present invention has at least the following beneficial effects:

[0033] Silicon wafer polishing is usually divided into three steps: rough polishing, intermediate polishing, and fine polishing. Intermediate polishing can not only repair the surface damage of silicon wafers during the rough polishing process, but also reduce the residual particles on the surface of silicon wafers. At present, in some silicon wafer substrate factories, the configuration of intermediate polishing liquid is to adjust the dilution ratio of the rough polishing liquid or directly add a certain amount of polymer to the rough polishing liquid. Since the rough polishing contains a large amount of alkaline additives, the intermediate polishing process is very likely to cause corrosion to the surface of silicon wafers and increase the residual particles on the surface of silicon wafers. In addition, in an alkaline state, the surface of silicon wafers and silicon oxide particles contains a large amount of Si-OH and Si-O - The two can easily form new chemical bonds through dehydration condensation reaction, thereby adsorbing on the surface of the silicon wafer, increasing the possibility of particles remaining on the surface of the silicon wafer.

[0034] The present invention provides a silicon wafer polishing liquid formula, which can effectively reduce the residual particles on the surface of the silicon wafer and improve the surface quality of the wafer by mixing and adding specially treated silicon dioxide hydrosol, organic base, anionic polymer and pH regulator. The specific reason is unclear, but it can be speculated that the mechanism of action is as follows: first, the alkalinity of the silica sol is reduced by organic acid, so that the Si-O - Secondly, the silica hydrosol is modified by adding an organic siloxane compound whose terminal group does not have a protonatable group, consuming a large number of Si-OH groups on the surface of the silica particles and grafting organic groups; finally, the surface of the silica particles is further coated by adding anionic surfactants, so that the remaining Si-OH and Si-O - The groups are basically not directly exposed in the polishing liquid, so they cannot form new chemical bonds with the surface of the silicon wafer, reducing the residual silicon oxide particles on the surface of the silicon wafer. In addition, by adding anionic water-soluble polymers to the polishing composition, the water-soluble polymers are easily adsorbed on the surface of the silicon wafer to form a layer of negative charge and organic barrier due to the low polarity of the Si-Si bond, which again reduces the risk of silicon oxide particles remaining on the surface of the silicon wafer. DETAILED DESCRIPTION

[0035] In order to better understand the technical solution of the present invention, the following examples will further illustrate the method provided by the present invention, but the present invention is not limited to the listed examples, and should also include any other known changes within the scope of the claims of the present invention.

[0036] A silicon wafer polishing composition comprises specially treated silicon dioxide hydrosol, an organic base, an anionic water-soluble polymer and water, and a pH regulator is used to adjust the pH to between 9.5 and 11.5, so as to greatly reduce the surface particle residue of the silicon wafer after polishing.

[0037] The specially treated silica hydrosol is prepared by the following steps:

[0038] 1) adding an organic acid solution to the silica hydrosol, adjusting the pH value of the silica sol to between 2.0 and 7.0, and stirring and mixing to obtain a dispersion A;

[0039] 2) Adding an organic siloxane compound and an anionic surfactant to the dispersion A in sequence, stirring and mixing them evenly, to obtain a specially treated silica hydrosol.

[0040] Specifically, the special treatment of the silica hydrosol exemplarily includes the following steps:

[0041] The first step is to weigh a certain amount of silica hydrosol (also known as "silica sol") and prepare a certain proportion of organic acid solution;

[0042] The second step is to slowly add a certain amount of organic acid solution to the silica sol under stirring, adjust the pH value of the silica sol to between 2.0 and 7.0, which is called dispersion A, and stir for 5 minutes;

[0043] In the third step, a certain amount of organic silicon oxane compound and anionic surfactant are added to the dispersion A in sequence, and stirred for 5 minutes to obtain a specially treated silica hydrosol.

[0044] In the special treatment process of the silica hydrosol of the present invention, the particle size of the silica hydrosol is 30-120nm, such as 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 110nm, etc., the particle size is a secondary particle size, and the solid content is 10-50wt%, such as 20wt%, 30wt%, 40wt%, etc. Based on the total mass of the silica hydrosol modified system, the amount of the silica hydrosol is 49-99%, such as including but not limited to 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 98%, etc., preferably 86%-95%.

[0045] In the special treatment process of the silica hydrosol of the present invention, the organic acid solution is a mixture of an organic acid and its derivatives and water, and the organic acid and its derivatives are selected from formic acid, acetic acid, propionic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, oxalic acid, succinic acid, malic acid, gluconic acid, alanine, glycine, lactic acid, trifluoroacetic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, propylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, 2-aminoethylphosphonic acid, 1-hydroxyethyl 1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid or their salts, preferably any one of oxalic acid, malonic acid, acetic acid and citric acid. Based on the total mass of the organic acid solution, the mass concentration of the organic acid in the organic acid solution is 0.1-50%, such as but not limited to 0.1%, 0.5%, 1%, 5%, 10%, 20%, 30%, 40%, 50%. Based on the total mass of the silica hydrosol modified system, the amount of the organic acid solution added to the silica hydrosol is 0.1-50%, such as but not limited to 0.1%, 0.5%, 1%, 5%, 10%, 20%, 30%, 40%, 50%, preferably 1-10%.

[0046] In the special treatment process of the silica hydrosol of the present invention, the end group of the organosiloxane compound does not contain a cationic group that can obtain a proton, for example, the end group does not contain an amine group or an amino group, and is specifically selected from phenyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropyltriethoxysilane, methyltrimethoxysilane, 1,1,3,3-tetramethyldisiloxane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 2-trimethylsiloxy-1,3-butadienebistrimethylsiloxymethylsilane, tetrapropoxysilane, triethoxysilane, 1,2-bis(trimethylsiloxy)ethane, 3-chloropropylmethyldimethoxysilane, triethylsilyl trifluoromethanesulfonate, 5-trifluoromethyl-2,4-bistrimethylsiloxypyrimidine, 1,7 - at least one of divinyl-octamethyltetrasiloxane, 1,1,3,3-tetramethyl-1,3-disiloxanediol, bis-3-methacryloxypropylated tetramethyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethoxydisiloxane, etherified product of polyethylene glycol monomethyl ether, 1-trimethylsilyloxy-3-trimethylsilyl-2-propynyl bis-3-methacryloxypropylated tetramethyldisiloxane, 1,3-dimethoxy-1,1,3,3-tetramethyldisiloxane, 2-(tert-butyldiphenylsilyloxy)ethanol, 4-((tert-butyldimethylsilyloxy)methyl)aniline, 1,5-divinyl-hexamethyltrisiloxane, and 1,3-bis(3-methacryloxypropyl)tetrakis(trimethylsilyloxy)disiloxane. Based on the total mass of the silica hydrosol modified system, the amount of the organosiloxane compound added to the silica hydrosol is 0.01-5%, for example including but not limited to 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, preferably 0.1-2%.

[0047] In the special treatment process of the silica hydrosol of the present invention, the anionic surfactant is mainly selected from fatty acid salts, sulfonates, sulfates and phosphates, and is specifically selected from decanylbenzenesulfonic acid, undecylbenzenesulfonic acid, dodecylbenzenesulfonic acid, hexadecylbenzenesulfonic acid, octadecylbenzenesulfonic acid, decanylsulfonic acid, undecylsulfonic acid, dodecylsulfonic acid, hexadecylsulfonic acid, octadecylsulfonic acid, succinic acid monooctadecylamidesulfonic acid, dodecyldiphenyletherdisulfonic acid, allyloxyhydroxypropanesulfonic acid, methacrylic acid hydroxypropanesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, allyloxysulfonic acid, decanylsulfuric acid, undecylsulfuric acid, dodecylsulfuric ... At least one of alkyl sulfate, octadecyl sulfate, dodecyl polyoxyethylene ether sulfate, undecyl polyoxyethylene ether sulfate, dodecyl polyoxyethylene ether sulfate, hexadecyl polyoxyethylene ether sulfate, octadecyl polyoxyethylene ether sulfate, alkyl alcohol polyoxyethylene ether sulfate, isomeric tridecyl alcohol polyoxyethylene ether sulfate, dodecyl polyoxyethylene ether carboxylic acid, undecyl polyoxyethylene ether carboxylic acid, dodecyl polyoxyethylene ether carboxylic acid, hexadecyl polyoxyethylene ether carboxylic acid, octadecyl polyoxyethylene ether carboxylic acid, methylene bisnaphthalene sulfonic acid, oleoyl methyl taurine, allyloxy nonylphenol polyoxyethylene ether monophosphate, isotridecanol ether phosphate, lauryl phosphate and their salts; preferably dodecylbenzene sulfonic acid. Based on the total mass of the silica hydrosol modified system, the amount of the anionic surfactant added to the silica hydrosol is 0.01-5%, for example, including but not limited to 0.01%, 0.05%, 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, preferably 0.1-2%.

[0048] The preparation method of the silicon wafer polishing composition of the present invention is not particularly limited, and conventional mixing steps in the art can be used. For example, a certain amount of organic base, anionic water-soluble polymer and water are added to a specially treated silica hydrosol, the pH value is adjusted with a pH adjuster, and the mixture is stirred and mixed until uniformly mixed.

[0049] In the present invention, the amount of the specially treated silica hydrosol added to the silicon wafer polishing composition is 5%-80%, based on the total mass of the polishing composition, for example, including but not limited to 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, preferably 10%-40%.

[0050] In the present invention, the organic base in the silicon wafer polishing composition is selected from at least one of methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, propylenediamine, butylenediamine, hydroxyethylethylenediamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, trihexyltetramine, 1-(2-aminoethyl)piperazine, N-methylpiperazine, piperazine, imidazole, methylimidazole, 1,2,4-triazole, 4-amino-1,2,4-triazole, guanidine carbonate, guanidine hydrochloride, guanidine nitrate, tetramethylammonium hydroxide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium fluoride, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium fluoride; more preferably, tetramethylammonium hydroxide. Based on the total mass of the polishing composition, the amount of organic base added is 0.5%-10%, for example including but not limited to 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, preferably 1-5%.

[0051] In the present invention, the pH value of the silicon wafer polishing composition is adjusted to be between 9.5 and 11.5 by adding a pH adjusting agent, such as 9.5, 10.0, 10.5, 11.0, and 11.5. The pH adjusting agent in the silicon wafer polishing composition is selected from hydrogen chloride, nitric acid, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide, imidazole, N-methylimidazole, 1,2,4-triazole, tetramethylguanidine, formic acid, acetic acid, propionic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, oxalic acid, succinic acid, malic acid, gluconic acid, alanine, glycine, lactic acid, trifluoroacetic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenediamine, and propylenediamine. At least any one of tetraacetic acid, hydroxyethylethylenediamine, hydroxyethylethylenediaminetriacetic acid, pyrophosphoric acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene 1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid or their salts, preferably any one of oxalic acid, hydrogen chloride, potassium hydroxide and tetramethylammonium hydroxide; more preferably potassium hydroxide or oxalic acid. Based on the total mass of the silicon wafer polishing composition, the added amount of the pH adjuster is 0.05%-5%, for example, including but not limited to 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, preferably 0.5-2%.

[0052] In the silicon wafer polishing composition of the present invention, the anionic water-soluble polymer is selected from polyacrylic acid, polymethacrylic acid, anionic polyacrylamide, polyethylene sulfonic acid, polypropylene sulfonic acid and salts thereof. Based on the total mass of the polishing composition, the amount of the anionic water-soluble polymer added is 0.01%-1%, for example, including but not limited to 0.01%, 0.05%, 0.1%, 0.5%, 1%, preferably 0.1%-1%.

[0053] The present invention is further explained below in conjunction with more specific embodiments, but does not constitute any limitation.

[0054] In the following embodiments, the instruments and parameters used in the polishing test of silicon wafer substrate materials are shown in Table 1, which includes three-step processes of rough, medium and fine. The SP5 produced by KLA was used to test the particle residue on the surface of the silicon wafer after fine polishing and cleaning, and only the particle residue of 26nm and above on the surface of each wafer after cleaning was counted. The standard RCA solution was used for cleaning, wherein the SC-1 solution ratio was as follows: ammonia water: hydrogen peroxide: water = 1:1:6. The SC-2 solution ratio was as follows: hydrogen chloride: hydrogen peroxide: water = 1:1:7. The rough polishing and fine polishing processes are shown in Tables 1 and 2, wherein the rough polishing liquid used Glanzox 1306 produced by Fujimi Company of Japan, with a dilution ratio of 30X, and the fine polishing liquid used Glanzox 3108 produced by Fujimi Company of Japan, with a dilution ratio of 30X.

[0055] Table 1 Rough polishing and medium polishing test process and parameters

[0056] Polishing machine model Ebara-300X Polishing pressure <![CDATA[250g / cm 2 ]]> Polishing composition flow rate 300mL / min Polishing pad Suba 800 Polishing time 3min Wafer diameter 300mm Polishing head / polishing disc speed 87 / 93rpm

[0057] Table 2 Fine polishing test process and parameters

[0058] Polishing machine model Ebara-300X Polishing pressure <![CDATA[250g / cm 2 ]]> Polishing composition flow rate 300mL / min Polishing pad Fujibo 274NX Polishing time 3min Wafer diameter 300mm Polishing head / polishing disc speed 87 / 93rpm

[0059] Unless otherwise specified, the raw materials and reagents used in the examples and comparative examples of the present invention were purchased from commercial sources. Unless otherwise specified, the purity was analytical grade or above.

[0060] The specific formula of the specially treated silica hydrosol used in the embodiments and comparative examples is shown in Table 3. Silica sol (60nm, 40wt%) represents silica sol with an average particle size of 60nm and a solid content of 40%, abbreviated as silica sol (60nm, 40wt%); 10% oxalic acid represents an oxalic acid solution with a mass concentration of 10wt%; polyacrylic acid (Mw: 2000) represents polyacrylic acid with a weight average molecular weight of 2000.

[0061] There are 10 numbers of specially treated silica hydrosols, in each number, 10 kg of untreated silica sol is used, and the concentration of the organic acid solution is 10%.

[0062] The specific preparation process of silica sol No. 1 is as follows: the first step is to weigh 10 kg of silica sol and prepare 5% oxalic acid solution. The second step is to slowly add 500 g of 10% oxalic acid solution, called dispersion A, to the 10 kg silica sol under stirring, and stir for 5 minutes. The third step is to add 100 g of vinyl triethoxysilane and 50 g of dodecylbenzene sulfonic acid to the dispersion A in turn, and stir for 5 minutes to obtain specially treated silica hydrosol No. 1.

[0063] The preparation process of other numbered silica sol samples is similar to that of No. 1 silica sol.

[0064] Table 3 Composition of specially treated silica hydrosol

[0065]

[0066]

[0067] The specific formula of the specially treated silica hydrosol used in the embodiments and comparative examples is shown in Table 4.

[0068] Table 4 Composition of Examples and Comparative Examples

[0069]

[0070]

[0071] The above-mentioned embodiments and comparative examples are all silicon wafer polishing composition stock solutions. Taking the preparation of 10 kg of the stock solution of Example 1 as an example, the specific preparation process is as follows: first, take 2500 g of specially treated No. 1 silica sol, and add 300 g of 25% tetramethylammonium hydroxide solution, 50 g of polyacrylic acid with a weight average molecular weight of 2000, 100 g of citric acid, 7050 g of deionized water, and stir for 5 minutes to obtain 10 kg of the polishing stock solution of Example 1.

[0072] Before use, the polishing liquids of the embodiments and comparative examples can be diluted with deionized water at different ratios as needed. In the above experiments, the polishing liquids of the embodiments and comparative examples were diluted with deionized water at a mass ratio of 1:30 before use. The performance test was carried out using the polishing compositions of the embodiments and comparative examples, and the particle results are shown in Table 5.

[0073] Table 5 Polishing performance test results of polishing composition

[0074]

[0075]

[0076] From the comparison of the above data, it can be seen that the use of the silicon wafer polishing composition of the present invention can greatly reduce the residual particles of 26nm and above on the surface of the silicon wafer after polishing. The number of residual particles of 26nm and above in the embodiments is <30, which has significant advantages compared with the comparative example. In combination with Example 1 and Comparative Examples 1-3, it can be seen that the synergistic addition of organic acid solution, organosiloxane compound and anionic surfactant can effectively reduce the surface particle size of the silicon wafer. From Example 1 and Comparative Example 4, it can be seen that the addition of cationic surfactants to the silica hydrosol cannot effectively reduce the surface particle size of the silicon wafer after cleaning. From Example 1 and Comparative Example 5, it can be seen that the treatment of silica hydrosol with an organosiloxane compound containing a protonatable group cannot effectively reduce the residual particles on the surface of the silicon wafer. From Example 1 and Comparative Examples 6-8, it can be seen that the specially treated silica hydrosol and the synergistic addition of anionic water-soluble polymers can effectively reduce the surface particle size of the silicon wafer.

[0077] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Those skilled in the art will appreciate that, under the guidance of this specification, some modifications or adjustments may be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A silicon wafer polishing composition, characterized in that: It includes specially treated silica hydrosol, organic base, anionic water-soluble polymer and water; The specially treated silica hydrosol is prepared by the following steps: 1) adding an organic acid solution to the silica hydrosol, adjusting the pH value of the silica sol to between 2.0 and 7.0, and stirring and mixing to obtain a dispersion A; 2) Adding an organic siloxane compound and an anionic surfactant to the dispersion A in sequence, stirring and mixing them evenly, to obtain a specially treated silica hydrosol.

2. The silicon wafer polishing composition according to claim 1, characterized in that Based on the total mass of the following substances, the mass percentage of each component used in the preparation process of the specially treated silica hydrosol is:

3. The silicon wafer polishing composition according to claim 2, characterized in that: The silica hydrosol has a particle size of 30-120 nm and a solid content of 10-50 wt %.

4. The silicon wafer polishing composition according to claim 2, characterized in that The organic acid solution is a mixture of an organic acid and its derivatives and water, and the mass concentration of the organic acid and its derivatives in the organic acid solution is 0.1-50%, preferably 1%-10%; Preferably, the organic acid and its derivatives are selected from at least any one of formic acid, acetic acid, propionic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, oxalic acid, succinic acid, malic acid, gluconic acid, alanine, glycine, lactic acid, trifluoroacetic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, propylenediaminetetraacetic acid, hydroxyethylethylenediaminetriacetic acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid or their salts, preferably any one of oxalic acid, malonic acid, acetic acid and citric acid.

5. The silicon wafer polishing composition according to claim 1, characterized in that The end groups of the organosiloxane compound do not contain cationic groups that can provide protons; Preferably, the organosiloxane compound is selected from phenyltrimethoxysilane, vinyl triethoxysilane, 3-chloropropyl triethoxysilane, methyl trimethoxysilane, 1,1,3,3-tetramethyl disiloxane, 3-(2,3-epoxypropyloxy)propyl trimethoxysilane, 2-trimethylsiloxy-1,3-butadiene bistrimethylsiloxymethylsilane, tetrapropoxysilane, triethoxysilane, 1,2-bis(trimethylsiloxy)ethane, 3-chloropropyl methyl dimethoxysilane, triethylsilyl trifluoromethanesulfonate, 5-trifluoromethyl-2,4-bistrimethylsiloxypyrimidine, 1,7-divinyl-octamethyltetrasiloxane, 1,1,3,3-tetramethyl At least one of 1,3-disiloxanediol, bis-3-methacryloxypropylated tetramethyldisiloxane, 1,3-divinyl-1,1,3,3-tetramethoxydisiloxane, etherified product of polyethylene glycol monomethyl ether, 1-trimethylsilyloxy-3-trimethylsilyl-2-propynyl bis-3-methacryloxypropylated tetramethyldisiloxane, 1,3-dimethoxy-1,1,3,3-tetramethyldisiloxane, 2-(tert-butyldiphenylsilyloxy)ethanol 4-((tert-butyldimethylsilyloxy)methyl)aniline, 1,5-divinyl-hexamethyltrisiloxane, and 1,3-bis(3-methacryloxypropyl)tetrakis(trimethylsilyloxy)disiloxane.

6. The silicon wafer polishing composition according to claim 1, characterized in that The anionic surfactant is selected from fatty acid salts, sulfonates, sulfate esters and phosphate esters; Preferably, the anionic surfactant is selected from the group consisting of decanylbenzene sulfonic acid, undecylbenzene sulfonic acid, dodecylbenzene sulfonic acid, hexadecylbenzene sulfonic acid, octadecylbenzene sulfonic acid, decanyl sulfonic acid, undecyl sulfonic acid, dodecyl sulfonic acid, hexadecyl sulfonic acid, octadecyl sulfonic acid, succinic acid monooctadecylamide sulfonic acid, dodecyl diphenyl ether disulfonic acid, allyloxy hydroxypropane sulfonic acid, methacrylic acid hydroxypropane sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, decanyl sulfuric acid, undecyl sulfuric acid, dodecyl sulfuric acid, hexadecyl sulfuric acid, octadecyl sulfuric acid, decanyl polyoxyethylene ether sulfuric acid Acid, undecyl polyoxyethylene ether sulfuric acid, dodecyl polyoxyethylene ether sulfuric acid, hexadecyl polyoxyethylene ether sulfuric acid, octadecyl polyoxyethylene ether sulfuric acid, isomeric tridecanol polyoxyethylene ether sulfuric acid, dodecyl polyoxyethylene ether carboxylic acid, undecyl polyoxyethylene ether carboxylic acid, dodecyl polyoxyethylene ether carboxylic acid, hexadecyl polyoxyethylene ether carboxylic acid, octadecyl polyoxyethylene ether carboxylic acid, methylene bisnaphthalene sulfonic acid, oleoyl methyl taurine, allyloxy nonylphenol polyoxyethylene ether monophosphate, isotridecanol ether phosphate, lauryl phosphate and their salts; preferably dodecylbenzene sulfonic acid.

7. The silicon wafer polishing composition according to any one of claims 1 to 6, characterized in that: Based on the total mass of the polishing composition, the following components are included in percentage by weight: Specially treated silica hydrosol 5%-80%; preferably 10%-40%; Organic base 0.5%-10%; preferably 1%-5%; Anionic water-soluble polymer 0.01%-1%; preferably 0.1%-1%; The balance is water; Preferably, a pH adjuster is also added to control the pH value of the polishing composition between 9.5 and 11.5; More preferably, the pH regulator is selected from the group consisting of hydrogen chloride, nitric acid, sulfuric acid, phosphoric acid, sodium hydroxide, potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide, imidazole, N-methylimidazole, 1,2,4-triazole, tetramethylguanidine, formic acid, acetic acid, propionic acid, itaconic acid, succinic acid, tartaric acid, citric acid, maleic acid, glycolic acid, malonic acid, oxalic acid, succinic acid, malic acid, gluconic acid, alanine, glycine, lactic acid, trifluoroacetic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, diethylenetriaminepentaacetic acid, triethylenediamine, propylenediaminetetraacetic acid , hydroxyethylethylenediamine, hydroxyethylethylenediaminetriacetic acid, pyrophosphoric acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene 1,1-diphosphonic acid, aminotrimethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid, ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-tricarboxylic acid or their salts, preferably any one of oxalic acid, hydrogen chloride, potassium hydroxide and tetramethylammonium hydroxide; more preferably potassium hydroxide or citric acid.

8. The silicon wafer polishing composition according to claim 1 or 7, characterized in that: The organic base is selected from at least one of methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, propylenediamine, butylenediamine, hydroxyethylethylenediamine, diethylenetriamine, monoethanolamine, N-(β-aminoethyl)ethanolamine, hexamethylenediamine, trihexylenetetramine, 1-(2-aminoethyl)piperazine, N-methylpiperazine, piperazine, imidazole, methylimidazole, 1,2,4-triazole, 4-amino-1,2,4-triazole, guanidine carbonate, guanidine hydrochloride, guanidine nitrate, tetramethylammonium hydroxide, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium fluoride, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetraethylammonium chloride, tetraethylammonium bromide, and tetraethylammonium fluoride; preferably tetramethylammonium hydroxide.

9. The silicon wafer polishing composition according to claim 1 or 7, characterized in that: The anionic water-soluble polymer is at least one selected from polyacrylic acid, polymethacrylic acid, anionic polyacrylamide, polyethylene sulfonic acid, polypropylene sulfonic acid, polystyrene sulfonic acid and salts thereof; Preferably, the weight average molecular weight of the anionic water-soluble polymer is 2000-10000000.

10. Use of the silicon wafer polishing composition according to any one of claims 1 to 9 in chemical mechanical polishing of silicon wafers.

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