Patent ID: 7936051

Claim:
A silicon wafer used in a semiconductor device manufacturing process which conducts heat treatment under conditions of a maximum temperature of 1100° C. or more and a rate of temperature increase of 300° C./sec or more after subjecting the silicon wafer to mirror machining, wherein, after slicing from a silicon monocrystal ingot, heat treatment is conducted so that a layer which has zero light scattering defects according to the 90° light scattering method is formed in a region at a depth from the wafer surface of 25 μm or more but less than 100 μm, and a layer which has a light scattering defect density of 1×10 8 /cm 3 or more according to the 90° light scattering method is formed in a region at a depth of 100 μm from the wafer surface.