Takakuma
Noriyuki Takakuma, Toyama-Shi JP
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20090042393 | Production method of polishing composition - A production method of a semiconductor device including: producing a polishing composition containing zirconium oxide sol; and planarizing a substrate having an uneven surface with said polishing composition, wherein the polishing composition containing zirconium oxide is produced by the steps comprising: baking at a temperature ranging from 400 to 1000° C., a zirconium compound having d50 (where d50 represents a particle diameter meaning that the number of particles having this particle diameter or less is 50% of the total number of particles) of zirconium compound particles of 5 to 25 μm and d99 (where d99 represents a particle diameter meaning that the number of particles having this particle diameter or less is 99% of the total number of particles) of zirconium compound particles of 60 μm or less, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry; and wet-grinding a powder of zirconium oxide obtained in the above baking in an aqueous medium until d50 of zirconium oxide particles becomes 80 to 150 nm and d99 of zirconium oxide particles becomes 150 to 500 nm, wherein d50 and d99 are measured by measuring a slurry of the zirconium compound by a laser diffractometry. | 02-12-2009 |
Noriyuki Takakuma, Toyama JP
Patent application number | Description | Published |
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20080254718 | Production Method of Polishing Composition - [Problems to Be Solved] To provide a method for obtaining a polishing composition by which a polishing speed is high and the polished surface has little surface failure. | 10-16-2008 |
Noriyuki Takakuma US
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20130055646 | Method for producing purified alkali silicate aqueous solution and silica sol - To provide a method for producing an alkali silicate aqueous solution containing a reduced amount of foreign substance of plate-like fine particles and a method for producing a silica sol containing a reduced amount of foreign substance of plate-like fine particles. A method for producing an alkali silicate aqueous solution fulfilling the following condition: the existing amount of plate-like fine particles having a length of one side of 0.2 to 4.0 μm and a thickness of 1 to 100 nm is determined to be 0 to 30%. The method for producing an alkali silicate aqueous solution includes the steps of adjusting a silica concentration of an alkali silicate aqueous solution to 0.5 to 10.0% by mass and filtering the alkali silicate aqueous solution through a filter having a removal rate of particles with a primary particle size of 1.0 μm of 50% or more. | 03-07-2013 |
Noriyuki Takakuma, Sodegaura-Shi JP
Patent application number | Description | Published |
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20130075651 | METHOD FOR PRODUCING PURIFIED ACTIVE SILICIC ACID SOLUTION AND SILICA SOL - A method for producing an active silicic acid solution in which the existing amount of foreign matters as plate-like fine particles is reduced and a method for producing a silica sol in which such foreign matters are reduced. The method fulfills the following condition: the existing amount of plate-like fine particles having a length of one side of 0.2 to 4.0 μm and a thickness of 1 to 100 nm is measured to be 0% to 30% in accordance with measuring method A, the method including the steps of: preparing an active silicic acid solution by subjecting an alkali silicate aqueous solution having a silica concentration of 0.5% by mass to 10.0% by mass to cation-exchange to remove alkaline components; and filtering the active silicic acid solution through a filter whose removal rate of particles having a primary particle size of 1.0 μm is 50% or more. | 03-28-2013 |