Patent ID: 6239004
Filing Date: 2001-05-29
Classification: H01L

Abstract:
A method of fabricating a bonded wafer, comprising the steps of:forming an oxide film on the surface of at least one of two mirror-polished silicon wafers;superposing the two silicon wafers such that the mirror-polished surfaces come into close contact with each other;heat-treating the wafers in order to join the wafers together firmly;reducing the thickness of one of the wafers so as to yield a thin film;polishing the surface of the thin film;performing vapor-phase etching in order to make the thickness of the thin film uniform;subjecting the surface of the bonded wafer to thermal oxidation to form an oxide film on the surface; andremoving the oxide film formed on the surface of the bonded wafer,wherein the thickness of the oxide film formed on the surface of the bonded wafer is made not greater than 50 nm.