Patent ID: 7364984

Claim:
A method for manufacturing an SOI substrate comprising the steps of: forming an oxide film ( 21 ) at least on one surface of a first silicon substrate ( 14 ); implanting hydrogen ions from the surface of the first silicon substrate ( 14 ) thereby forming an ion-implantation zone ( 16 ) in the interior of the first silicon substrate ( 14 ); bonding the first silicon substrate ( 14 ) over a second silicon substrate ( 12 ) with the oxide film ( 21 ) interposed between the first and second substrates thereby forming a laminated assembly ( 15 ); subjecting the laminated assembly ( 15 ) to a first heating treatment consisting of heating at a specified temperature, so that the first silicon substrate ( 14 ) is split at the ion-implantation zone ( 16 ) thereby manufacturing a bonded substrate ( 18 ) in which a thin SOI layer ( 13 ) is formed on the second silicon substrate ( 12 ) with the oxide film ( 21 ) interposed between the SOI layer and the second substrate; subjecting the bonded substrate ( 18 ) to a second heating treatment consisting of heating at 750 to 900° C. in an oxidative atmosphere thereby reducing damage to the SOI layer ( 13 ); and subjecting the resulting bonded substrate ( 18 ) to a third heating treatment consisting of heating at 900 to 1200° C. thereby enhancing the bonding strength of the bonded substrate ( 18 ).