| 摘要 |
A final polishing method comprising using: a polishing agent which contains colloidal silica, ammonia and hydroxyethyl cellulose, and in which the primary particle diameter of the colloidal silica is 20 nm or more and less than 30 nm, the weight-average molecular weight of hydroxyethyl cellulose is 400,000 or more and not more than 700,000, and the ratio D1/D2 [wherein D1 represents a particle diameter corresponding to a cumulative volume ratio of 95% of particles present in the polishing agent, and D2 represents a particle diameter corresponding to a cumulative volume ratio of 95% of the colloidal silica in the case of dispersing the colloidal silica in water so as to give the same concentration as the colloidal silica concentration of the polishing agent] is 1.5 or more and not more than 2.5; and a polishing cloth which shows a contact angle of 60° or more, said contact angle being measured 100 seconds after dropping purified water on the polishing cloth that has been seasoned and dried. Thus, provided is a method for final polishing of a silicon wafer whereby a silicon wafer having an excellent haze level as a whole, little haze irregularity in an outer circumferential part and few minute defects can be obtained. |
