| 摘要 |
PROBLEM TO BE SOLVED: To provide a forming method of a laminated SOI substrate, which first suppresses irregularities in the depth directions of recessed parts, which are formed in a first silicon substrate (substrate to be polished) and are used as reference planes for polishing a buried oxide film, to form the laminated SOI substrate, which is formed by a selective polishing method to use the buried oxide film as a polishing stopper and has a SOI layer, which is excellent in the uniformity of its film thickness. SOLUTION: The forming method of a laminated SOI substrate has a process to form recessed parts in the prescribed regions on a first silicon substrate 101, a process to form an insulating film in such a way as to fill at least the recessed parts, a process to laminate together the recessed part formation surfaces of the substrate 101 with a second silicon substrate, a process to grind the surface on the opposite side to the laminated surface of the substrate 101 with the second silicon substrate and a process to selectively polish the ground surface and moreover, the forming method has a process to introduce impurities to change the etching rate of a silicon film in the regions, which are formed with the recessed parts, prior to the formation of the recessed parts.
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