| 摘要 |
PROBLEM TO BE SOLVED: To make a wafer free of OSF and COP, even if a conventional thermal treatment for making OSF obvious is carried out, make oxide deposition uniform over the whole surface of the wafer and obtain uniform gettering effects, without variation between the circumferential edge and central part of the wafer. SOLUTION: Oxygen concentration of a silicon wafer, with which crystal oriented particles(COPs) and penetration-type displacements(L/Ds) are not produced on a wafer surface is not larger than 1.2×1018 atoms/cm3 (old ASTM). If the silicon wafer is subjected to a thermal treatment at 1,000 deg.C±30 deg.C for 2-5 hours in an oxygen atmosphere, and successively, is subjected to a thermal treatment at 1,130 deg.C±30 deg.C for 1-16 hours, oxidation starting failures(OSFs) are made obvious in the central part of the silicon wafer. A polycrystalline silicon layer with a thickness of 1.3±0.3μm is formed on the rear surface of the silicon wafer at a temperature of 670 deg.C±30 deg.C by chemical vapor phase deposition(CVD) method.
|
