Method for manufacturing SOI wafer
This method for manufacturing an SOI wafer includes: a step of forming insulating films in a front surface and a mirror-polished rear surface of an active layer wafer; a step of removing the insulating film in the front surface of the active layer wafer; a step of subjecting the active layer wafer to a rapid thermal annealing process; a step of bonding the active layer wafer and a support wafer with the insulating film formed in the rear surface therebetween so as to form a bonded wafer; a step of subjecting the bonded wafer to a heat treatment for bonding enhancement which enhances a bonding strength between the active layer wafer and the support wafer; and a step of thinning the active layer wafer in the bonded wafer so as to form an SOI layer.
1. A method for manufacturing an SOI wafer, said method comprising:
forming insulating films in a front surface and a mirror-polished rear surface of an active layer wafer;
removing said insulating film in said front surface of said active layer wafer;
after the removing, subjecting said active layer wafer to a rapid thermal annealing process in a nitridation gas atmosphere to form a vacancy layer including vacancies in a surface portion of said front surface;
bonding said active layer wafer and a support wafer with said insulating film formed in said rear surface therebetween so as to form a bonded wafer, after the rapid thermal annealing process;
subjecting said bonded wafer to a heat treatment for bonding enhancement in an oxidizing atmosphere which enhances a bonding strength between said active layer wafer and said support wafer and forms a denuded zone layer in said surface portion of said front surface and a BMD layer under said denuded zone layer in said active layer wafer; and
thinning said active layer wafer in said bonded wafer and removing said denuded zone layer and said BMD layer so as to form an SOI layer in a surface portion of said rear surface of said active layer wafer.
2. The method for manufacturing an SOI wafer according to claim 1 , wherein said rapid thermal annealing process is conducted in a nitridation gas atmosphere,
said rapid thermal annealing process comprises: heating up a temperature from room temperature to a preset temperature at a heating up rate of 10 to 100° C./sec; holding said preset temperature for 1 to 60 seconds; and lowering said temperature from said preset temperature to room temperature at a lowering rate of 10 to 100° C./sec, and
said preset temperature is set to in a range from 1100° C. to 1250° C.