METHOD FOR MANUFACTURING SEMICONDUCTOR SUBSTRATE

PROBLEM TO BE SOLVED: To uniform treatment applied to a wafer in manufacturing a semiconductor substrate. SOLUTION: The method includes a process to form a nonporous layer on a porous layer which is formed on the surface of a first substrate, a process of laminating the first substrate and a second substrate prepared separately so as to sandwich the nonporous layer, a process of removing the first substrate from the laminated substrate so as to expose the porous layer on the second substrate, and a process of etching the porous layer by supplying ultrasonic waves so as to expose the second substrate surface in a state that the second substrate, whose porous layer is exposed, is immersed in etching liquid perfectly. In the etching process, the strength of the ultrasonic wave acting on the second substrate is varied. COPYRIGHT: (C)2004,JPO