Method of separating a semiconductor wafer with dielectrics

摘要

A method for separating a joined substrate type wafer, which wafer is composed of a pair of semiconductor substrates joined through an insulation film, utilizes dielectrics through simple processing steps. Trenches for separating a semiconductor substrate with dielectrics are dug from the surface of the substrate and a dielectrics film is deposited on the surface of the substrate including the trenches. Then poly-crystalline silicon is grown by CVD to a thickness of about 0.5 mu m, which is deep enough to fill the trenches. The process time for growing poly-crystalline silicon is shortened, and the processing step for removing the poly-crystalline silicon deposited on the unwanted areas is eliminated by growing the poly-crystalline silicon in the trenches but not on the crystalline surface of semiconductor regions based on the growth rate dependence of the poly-crystalline silicon on the crystallinity of the surface on which the poly-crystalline silicon is grown.