Abstract: An object is to provide a cage silicate that can be industrially safely and simply produced by using an alkali silicate solution that does not generate alcohol as a Si raw material and using non-toxic quaternary ammonium, and a method for producing the same. The problem is solved by the following cage silicate: A cage silicate consisting of anion component 1 represented by following formula (1), anion component 2 which is a mineral acid ion, cation component 1 represented by following formula (2), and cation component 2 which is an alkali ion, in which, to the mole number in terms of SiO2, a ratio of the mole number of water, (H2O/SiO2), is 0.7 to 30, a ratio of the mole number of alkali ions, (alkali ions/SiO2), is 1.0×10?7 to 1.0×10?2, and a ratio of the mole number of the mineral acid ions, (mineral acid ions/SiO2), is 1.0×10?7 to 1.0×10?3. In formula (2), R represents an alkyl group having 2 to 20 carbon atoms.

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: 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 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.

Abstract: An object is to provide a polishing liquid composition that can provide hydrophilicity to a wafer surface and effectively improve a haze in polishing of wafers for substrates in electronics industry. The present invention is a polishing liquid composition for wafers, comprising: water; silica particles; an alkaline compound; a polyvinyl alcohol; an anion-modified polyvinyl alcohol; and a surfactant, wherein the mass ratio of the anion-modified polyvinyl alcohol to the polyvinyl alcohol is 0.6 to 5.5. The anion-modified polyvinyl alcohol is preferably a polyvinyl alcohol modified with a carboxy group or a sulfonic acid group.

Abstract: An object is to provide a polishing liquid composition that can provide hydrophilicity to a wafer surface and effectively improve a haze in polishing of wafers for substrates in electronics industry. The present invention is a polishing liquid composition for wafers, comprising: water; silica particles; an alkaline compound; a polyvinyl alcohol; an anion-modified polyvinyl alcohol; and a surfactant, wherein the mass ratio of the anion-modified polyvinyl alcohol to the polyvinyl alcohol is 0.6 to 5.5. The anion-modified polyvinyl alcohol is preferably a polyvinyl alcohol modified with a carboxy group or a sulfonic acid group.

Abstract: There is provided a polishing liquid composition that can effectively reduce LPDs having a size of 50 nm or less on a wafer surface in polishing of semiconductor wafers. A semiconductor wafer polishing liquid composition including: water; silica particles; an alkaline compound; a water-soluble polymer compound; and polyethylene glycol, wherein the semiconductor wafer polishing liquid composition satisfies conditions (a) to (c): (a) a shape factor SF1 of the silica particles is 1.00 to 1.20, (b) a mean primary particle diameter of the silica particles that is obtained by a nitrogen adsorption method is 5 nm to 100 nm, and a coefficient of particle diameter variation CV value obtained from image analysis of the transmission electron microscope image is in a range of 0% to 15%, and (c) the polyethylene glycol has a number average molecular weight of 200 to 15,000.