Composite substrate manufacturing method, and composite substrate

摘要

Disclosed is a composite substrate manufacturing method whereby, after bonding a semiconductor substrate (1) and a supporting substrate (3) to each other, the semiconductor substrate (1) is thinned, and a composite substrate (8) having a semiconductor layer (6) on the supporting substrate (3) is obtained. On the supporting substrate (3) surface to be bonded, a coating film (4a) containing polysilazane is formed, a silicon-containing insulating film (4) is formed by performing firing by heating the coating film (4a) to 600-1,200° C., then, the semiconductor substrate (1) and the supporting substrate (3) are bonded to each other with the insulating film (4) therebetween, thereby suppressing bonding failures due to surface roughness and defects of the supporting substrate, and easily obtaining the composite substrate.

主权项

1. A method for preparing a composite substrate, comprising the steps of:
coating a polysilazane-containing coating composition on the surface of a support substrate of SiC or GaN to be bonded, to form a polysilazane-containing coating; subjecting the coating to firing treatment of heating at 600° C. to 1,200° C. to form a silicon-containing insulating film, wherein the insulating film as of firing treatment has a thickness of 10 to 200 nm and a surface roughness Rms of up to 1.0 nm, and thereafter; bonding a semiconductor substrate to the support substrate via the insulating film, while keeping the thickness of the insulating film as of the firing treatment; and thinning the semiconductor substrate for thereby yielding the composite substrate having a semiconductor layer on the support substrate.