Patent ID: 7141113

Claim:
A heat treating method consisting of the steps of distributing oxide precipitates in a silicon single crystal wafer by a first step of maintaining a first heat treatment temperature for an initial entry of the silicon single crystal wafer up to 500° C., and a second step of maintaining a temperature ramping rate in a temperature range from the first heat treatment temperature to a second heat treatment temperature of 700° C.–900° C., said ramping rate being 1° C./min or less, said first step being performed first after a wafer slicing process, said wafer comprising a surface region of up to several tens of μm deep from a wafer surface and a bulk region of several tens or more of μm deep from the wafer surface, said wafer having been prepared from a crystal free from grown-in defects and produced by a Czochralski method, said oxide precipitates being uniformly distributed in the bulk region.