Abstract: Provided is a method that is for polishing a silicon wafer by a polishing device using a carrier holding the silicon wafer, and that can reduce wear on the carrier. In this polishing method, a polishing liquid used in the polishing device contains 0.1-5 mass %, in terms of the concentration of silica, silica particles comprising: silica particles (A) having an average primary particle size of 4-30 nm as measured by BET, and having an (X2/X1) ratio of 1.2-1.8, where X2 (nm) represents an average particle size along the major axis thereof as calculated from a perspective projection image obtained using an electron beam, and X1 (nm) represents the average primary particle size as measured by BET; and silica particles (B) having an average primary particle size of more than 30 nm but not more than 50 nm as measured by BET, and having a (X2/X1) ratio of 1.2-1.

Abstract: A polishing composition used in wafer polishing process for eliminating protrusion around laser mark, thereby achieving a flat polished surface, as well as a wafer polishing method using the polishing composition. A post-polishing composition for elimination of a laser mark remaining after polishing of silicon wafer with a primary polishing composition containing silica particles, water, and a basic compound, the post-polishing composition including silica particles, water, a tetraalkylammonium ion, and a water-soluble polymer, wherein the mass ratio of the tetraalkylammonium ion to SiO2 of the silica particles is 0.200 to 1.000:1; the mass ratio of SiO2 dissolved in the polishing composition to SiO2 of the silica particles is 0.100 to 1.500:1; and the mass ratio of the water-soluble polymer to SiO2 of the silica particles is 0.005 to 0.05:1. The silica particles have an average primary particle diameter of 1 nm to 100 nm.

Abstract: A polishing composition eliminating protrusions around a laser mark in wafer polishing processes, the manufacturing method therefor and a polishing method using the composition. The polishing composition including silica particles and water, wherein: the composition includes a tetraalkylammonium ion such that the mass ratio of the ion to SiO2 of the silica particles is 0.400 to 1.500:1, and the mass ratio of SiO2 dissolved in the polishing composition to SiO2 is 0.100 to 1.500:1; the tetraalkylammonium ion is derived from a compound selected from the group made of an alkali silicate, a hydroxide, a carbonate, a sulfate, and a halide while the ion is contained in the polishing composition in 0.2% by mass to 8.0% by mass; and the dissolved SiO2 is derived from a tetraalkylammonium silicate, a potassium silicate, a sodium silicate, or a mixture of any of these.

Abstract: A polishing composition used in wafer polishing process for eliminating protrusion around laser mark, thereby achieving a flat polished surface, as well as a wafer polishing method using the polishing composition. A post-polishing composition for elimination of a laser mark remaining after polishing of silicon wafer with a primary polishing composition containing silica particles, water, and a basic compound, the post-polishing composition including silica particles, water, a tetraalkylammonium ion, and a water-soluble polymer, wherein the mass ratio of the tetraalkylammonium ion to SiO2 of the silica particles is 0.200 to 1.000:1; the mass ratio of SiO2 dissolved in the polishing composition to SiO2 of the silica particles is 0.100 to 1.500:1; and the mass ratio of the water-soluble polymer to SiO2 of the silica particles is 0.005 to 0.05:1. The silica particles have an average primary particle diameter of 1 nm to 100 nm.

Abstract: Provided is a method that is for polishing a silicon wafer by a polishing device using a carrier holding the silicon wafer, and that can reduce wear on the carrier. In this polishing method, a polishing liquid used in the polishing device contains 0.1-5 mass %, in terms of the concentration of silica, silica particles comprising: silica particles (A) having an average primary particle size of 4-30 nm as measured by BET, and having an (X2/X1) ratio of 1.2-1.8, where X2 (nm) represents an average particle size along the major axis thereof as calculated from a perspective projection image obtained using an electron beam, and X1 (nm) represents the average primary particle size as measured by BET; and silica particles (B) having an average primary particle size of more than 30 nm but not more than 50 nm as measured by BET, and having a (X2/X1) ratio of 1.2-1.

Abstract: Provided is a method that is for polishing a silicon wafer by a polishing device using a carrier holding the silicon wafer, and that can reduce wear on the carrier. In this polishing method, a polishing liquid used in the polishing device contains 0.1-5 mass %, in terms of the concentration of silica, silica particles comprising: silica particles (A) having an average primary particle size of 4-30 nm as measured by BET, and having an (X2/X1) ratio of 1.2-1.8, where X2 (nm) represents an average particle size along the major axis thereof as calculated from a perspective projection image obtained using an electron beam, and X1 (nm) represents the average primary particle size as measured by BET; and silica particles (B) having an average primary particle size of more than 30 nm but not more than 50 nm as measured by BET, and having a (X2/X1) ratio of 1.2-1.

Abstract: A polishing composition having silica-based abrasive grains and a polishing method. A polishing composition having silica particles, wherein on the basis of a colloidal silica dispersion of the silica particles, the dispersion has an Rsp of 0.15 to 0.7 as measured using pulse NMR, and the colloidal silica particles have a shape coefficient SF1 of 1.20 to 1.80, wherein Rsp is calculated based on equation (1): Rsp=(Rav?Rb)/(Rb)??(1) (wherein Rsp is an index that indicates water affinity; Rav is an inverse of a relaxation time of the colloidal silica dispersion; and Rb is an inverse of a relaxation time of a blank aqueous solution obtained by removing the silica particles from the colloidal silica dispersion), and the shape coefficient SF1 is calculated based on equation (2): SF1=(area of a circle whose diameter is a maximum diameter of the particle)/(projected area)??(2).

Abstract: There are provided a polishing composition that gives, in the step of polishing a wafer, a flat polished surface having a reduced height difference between a central region and a peripheral region (laser mark region) of the wafer, and a method for producing a wafer using the polished composition. A polishing composition comprising water, silica particles, an alkaline substance, and an amphoteric surfactant of formula (1): wherein R1 is a C10-20 alkyl group, or a C1-5 alkyl group containing an amide group; R2 and R3 are each independently a C1-9 alkyl group; and X?is a C1-5 anionic organic group containing a carboxylate ion or a sulfonate ion. Silica particles in the form of an aqueous dispersion of silica particles having a mean primary particle diameter of 5 to 100 nm may be used. A method for producing a wafer, wherein in the step of polishing a wafer, polishing is performed until a height difference between a central region and a peripheral region of the wafer becomes 100 nm or less.

Abstract: A polishing composition that is for use in CMP polishing and that makes it possible to minimize the occurrence of defects. A polishing composition comprising silica particles, a basic nitrogen-containing organic compound, and water serving as a solvent, wherein the composition exhibits an Rsp value of the following Formula (1) of more than 0.7 and 6 or less as calculated from values measured by pulse NMR: Rsp=(Rav?Rb)/(Rb) . . . (1) (wherein Rsp is an index of water affinity; Rav is the reciprocal of the relaxation time of the polishing composition; and Rb is the reciprocal of the relaxation time of the water serving as a solvent of the polishing composition).

Abstract: A polishing composition eliminating protrusions around a laser mark in wafer polishing processes, the manufacturing method therefor and a polishing method using the composition. The polishing composition including silica particles and water, wherein: the composition includes a tetraalkylammonium ion such that the mass ratio of the ion to SiO2 of the silica particles is 0.400 to 1.500:1, and the mass ratio of SiO2 dissolved in the polishing composition to SiO2 is 0.100 to 1.500:1; the tetraalkylammonium ion is derived from a compound selected from the group made of an alkali silicate, a hydroxide, a carbonate, a sulfate, and a halide while the ion is contained in the polishing composition in 0.2% by mass to 8.0% by mass; and the dissolved SiO2 is derived from a tetraalkylammonium silicate, a potassium silicate, a sodium silicate, or a mixture of any of these.

Abstract: Provided is a method that is for polishing a silicon wafer by a polishing device using a carrier holding the silicon wafer, and that can reduce wear on the carrier. In this polishing method, a polishing liquid used in the polishing device contains 0.1-5 mass %, in terms of the concentration of silica, silica particles comprising: silica particles (A) having an average primary particle size of 4-30 nm as measured by BET, and having an (X2/X1) ratio of 1.2-1.8, where X2 (nm) represents an average particle size along the major axis thereof as calculated from a perspective projection image obtained using an electron beam, and X1 (nm) represents the average primary particle size as measured by BET; and silica particles (B) having an average primary particle size of more than 30 nm but not more than 50 nm as measured by BET, and having a (X2/X1) ratio of 1.2-1.

Abstract: There is provided a method for obtaining a purified aqueous solution of silicic acid containing less metal impurities such as Cu and Ni using water glass as a raw material with less number of purification steps than that in conventional methods without using any unnecessary additives. The method for producing a purified aqueous solution of silicic acid, the method comprising the steps of: (a) passing an aqueous solution of alkaline silicate having a silica concentration of 0.5% by mass or more and 10% by mass or less through a column filled with a polyamine-, iminodiacetic acid-, or aminophosphoric acid-type chelating resin, and (b) passing the aqueous solution passed in the step (a) through a column filled with a hydrogen-type cation exchange resin.

Abstract: A polishing composition for eliminating a protrusion around a laser mark on a laser mark-provided wafer and a wafer polishing method for polishing a protrusion around a laser mark, the polishing composition including a water-soluble compound, a chelating agent, and metal oxide particles, and having a pH of 7 to 12, wherein the water-soluble compound has a hydrophobic moiety and a hydrophilic moiety; the hydrophilic moiety has, on an end or side chain thereof, a hydroxyl group and a hydroxyethyl group, an acyloxy group, a carboxylic acid group, a carboxylic acid salt group, a sulfonic acid group, or a sulfonic acid salt group; and the water-soluble compound is contained in an amount of 5 to 700 ppm in the polishing composition. The metal oxide particles are silica particles, zirconia particles, or ceria particles contained in a colloidal sol and having an average primary particle diameter of 5 to 100 nm.

Abstract: A polishing composition having silica-based abrasive grains and a polishing method. A polishing composition having silica particles, wherein on the basis of a colloidal silica dispersion of the silica particles, the dispersion has an Rsp of 0.15 to 0.7 as measured using pulse NMR, and the colloidal silica particles have a shape coefficient SF1 of 1.20 to 1.80, wherein Rsp is calculated based on equation (1): Rsp=(Rav?Rb)/(Rb)??(1) (wherein Rsp is an index that indicates water affinity; Rav is an inverse of a relaxation time of the colloidal silica dispersion; and Rb is an inverse of a relaxation time of a blank aqueous solution obtained by removing the silica particles from the colloidal silica dispersion), and the shape coefficient SF1 is calculated based on equation (2): SF1=(area of a circle whose diameter is a maximum diameter of the particle)/(projected area)??(2).

Abstract: A polishing composition that gives, in the step of polishing a wafer, a flat polished surface having a reduced height difference between a central region and a peripheral region of the wafer, and a method for producing a wafer using the polished composition. A polishing composition comprising water, silica particles, an alkaline substance, and an amphoteric surfactant of formula (1): wherein R1 is a C10-20 alkyl group, or a C1-5 alkyl group containing an amide group; R2 and R3 are each independently a C1-9 alkyl group; and X? is a C1-5 anionic organic group containing a carboxylate ion or a sulfonate ion. A method for producing a wafer, wherein in the step of polishing a wafer, polishing is performed until a height difference between a central region and a peripheral region of the wafer becomes 100 nm or less.

Abstract: There is provided a method for obtaining a purified aqueous solution of silicic acid containing less metal impurities such as Cu and Ni using water glass as a raw material with less number of purification steps than that in conventional methods without using any unnecessary additives. The method for producing a purified aqueous solution of silicic acid, the method comprising the steps of: (a) passing an aqueous solution of alkaline silicate having a silica concentration of 0.5% by mass or more and 10% by mass or less through a column filled with a polyamine-, iminodiacetic acid-, or aminophosphoric acid-type chelating resin, and (b) passing the aqueous solution passed in the step (a) through a column filled with a hydrogen-type cation exchange resin.