Patent ID: 7078357
Filing Date: 2006-07-18
Classification: H01L

Abstract:
1. A method for manufacturing a silicon wafer comprising the steps of: performing heat treatment (RTA treatment) to a silicon wafer containing interstitial oxygen with a rapid heating-rapid cooling apparatus, thereby atomic vacancies being injected from a surface of the wafer to form a maximum position of an atomic vacancy concentration in a depth direction in the vicinity of the surface of the wafer; and performing heat treatment (post annealing) to move the maximum position of the atomic vacancy concentration in the vicinity of the surface of the wafer into the inside of the wafer, wherein the RTA treatment is performed in an atmosphere containing nitrogen in a temperature range of 1100 to 1350° C., wherein the post annealing is performed in a temperature range of 700 to 1050° C., and wherein the RTA treatment is performed at a temperature higher than an optimal temperature at which an amount of precipitated oxygen or BMD density is maximized, and wherein the optimal temperature at which the amount of precipitated oxygen or the BMD density is maximized is determined by providing plural silicon wafers prepared under the same conditions as the silicon wafer containing interstitial oxygen, subjecting each wafer thereof to the RTA treatment at respective plural different temperatures selected in the temperature range of 1100° C. to 1350° C., and thereafter applying oxygen precipitation treatment to the plural silicon wafers subjected to the RTA treatment, to obtain a relationship between the amount of precipitated oxygen or the BMD density and an RTA treatment temperature.