| 摘要 |
PROBLEM TO BE SOLVED: To prevent cup-shaped transformation which arises when polishing a silicon substrate, by etching the first silicon substrate polished primarily until the region doped with impurities is removed, and further, secondarily polishing the first silicon substrate to manufacture an SOI wafer. SOLUTION: When joining the second silicon substrate 210 to the first silicon substrate 201, the top surface of the second silicon substrate 210 is joined to abut on the second insulating film 209 made on the first silicon substrate 201, and then it is heat-treated, and the rear of the first silicon substrate 201 is primarily polished by chemomechanical polishing process. This primary polishing is executed nearly to the section where impurities 203 are distributed. Furthermore, the rear of the first silicon substrate 201 is wetly etched until the region where impurities are distributed is removed by etchant, and then the secondary polishing process using an element isolating film 208a as polishing stop layer is performed, thus an SDI wafer possessing an element isolating film is manufactured.
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