| 摘要 |
PURPOSE:To provide thin-film silicon on the whole area of a wafer by selectively lapping a first silicon wafer that is fixed by means of projections formed on a second oxide layer. CONSTITUTION:A first silicon wafer 1 for device formation is oxidized in steam to form a first oxide film 11. A second silicon wafer 2, used as a support, is oxidized in steam to form a second oxide film 21 on it. The first oxide film 11 is patterned to remove part of it. The first silicon wafer 1 is etched in the parts where the oxide film has been removed, so that recesses 12 are formed. The second oxide film 21 is patterned and etched away leaving the parts corresponding to the recesses 12, so that projections 22 are formed. The two wafers are stacked with the projections 12 and recesses 22 engaged, and they are heated in an oxygen atmosphere and joined. The first wafer 1 is ground and lapped selectively until the projections 22 are exposed in all the area. In this manner, a thin silicon layer 13 of uniform thickness is provided for device formation.
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