Method for planarizing a semiconductor substrate

摘要

A method for planarizing a semiconductor substrate uses a difference in etch selectivity of insulators on the semiconductor substrate. The method comprises the steps of wet-etching the second and first insulating layers at upper edges of the elevated region until portions of the first insulating layer are exposed at the upper edges, forming a third insulating layer on the first and second insulating layers, and wet-etching the third and second insulating layers until an upper surface of the first insulating layer is exposed. During the wet-etching, the second insulating layer is etched faster than the third insulating layer. With this method, the semiconductor substrate has an even surface.