Patent ID: 8962352
Filing Date: 2015-02-24
Classification: G01B,H01L

Abstract:
1. A method for calculating a warpage of a bonded SOI wafer that is fabricated by forming a thermal oxide film on one surface or both surfaces of one of a bond wafer and a base wafer that are formed of silicon single crystal wafers, bonding the bond wafer and the base wafer to each other through the thermal oxide film, then reducing a film thickness of the bond wafer, thereby fabricating an epitaxial growth SOI wafer constituted of a BOX layer on the base wafer and an SOI layer on the BOX layer, and thereafter growing an epitaxial layer on a surface of the SOI layer, the method comprising: assuming that the epitaxial growth SOI wafer is a silicon single crystal wafer having the same dopant concentration as dopant concentration of the bond wafer; calculating a warpage A that occurs at the time of performing the epitaxial growth relative to the assumed silicon single crystal wafer; calculating a warpage B caused due to a thickness of the BOX layer of the epitaxial growth SOI wafer; determining a measured value of a warpage of the base wafer before bonding as a warpage C; and calculating a sum of the warpages (A+B+C) as the warpage of the bonded SOI wafer.