Method for Producing Bonded Wafer

Abstract

A bonded wafer is produced by comprising a step of implanting oxygen ions from a surface of a wafer for active layer to form an oxygen ion implanted layer at a given position inside the wafer for active layer; a step of bonding the wafer of active layer to a wafer for support substrate directly or through an insulating film; a step of subjecting the resulting bonded wafer to a heat treatment for increasing a bonding strength; a step of removing a portion of the wafer for active layer in the bonded wafer to a given position not exposing the oxygen ion implanted layer by a given method; a step of exposing the entire surface of the oxygen ion implanted layer; and a step of removing the exposed oxygen ion implanted layer to obtain an active layer of a given thickness, wherein the step of exposing the entire surface of the oxygen ion implanted layer is carried out by a dry etching under given conditions.

1 . A method for producing a bonded wafer, comprising a step of implanting oxygen ions from a surface of a wafer for active layer to form an oxygen ion implanted layer at a given position inside the wafer for active layer; a step of bonding the wafer of active layer to a wafer for support substrate directly or through an insulating film so as to form a bonded wafer; a step of subjecting the resulting bonded wafer to a heat treatment for increasing a bonding strength; a step of removing a portion of the wafer for active layer in the bonded wafer to a given position not exposing the oxygen ion implanted layer by a given method; a step of exposing the entire surface of the oxygen ion implanted layer; and a step of removing the exposed oxygen ion implanted layer to obtain an active layer of a given thickness, wherein the step of exposing the entire surface of the oxygen ion implanted layer is carried out by a dry etching under given conditions. 
   
   
       2 . A method for producing a bonded wafer according to  claim 1 , wherein the dry etching is a reactive ion etching using a mixed gas of sulfur hexafluoride, carbon tetrafluoride, trifluoromethane or xenon difluoride, and oxygen or hydrogen chloride as a dry etching gas. 
   
   
       3 . (canceled) 
   
   
       4 . A method for producing a bonded wafer according to  claim 1 , wherein a crystal orientation of a bonding face between the wafer for active layer and the wafer for support substrate is <100>, <110> or <111>.