Patent ID: 7632349

Claim:
A method for evaluating surface defects of a silicon wafer comprising: a rapid heat treatment step wherein a silicon wafer cut out from a silicon single-crystal ingot is subjected to a heat treatment in an atmosphere which includes at least one of an NH 3 gas, N 2 gas, N 2 O gas, an NO gas, or a mixed gas atmosphere containing these gases with an inert gas, and wherein the temperature is elevated at a speed of 10 to 150° C./second from a room temperature to temperatures between 1170° C. and less than the melting point of silicon, holding the silicon wafer at this processing temperature for 1 to 120 seconds, and then cooling the silicon wafer to the room temperature at a temperature lowering speed of 10 to 100° C./second; and a step of detecting a region on the wafer surface where small COP's exist at least by a particle counter using a surface photo voltage method to calculate a minority carrier diffusion length on the wafer surface, wherein a detected amount of the small COP's which are not smaller than 0.065 μm, when measured by an SP-1 particle counter, is substantially zero.