JPS6436029A - Formation of pattern of polycrystalline semiconductor thin film - Google Patents

Abstract

PURPOSE:To reduce a material and a duration for manufacturing a semiconductor device by a method wherein only a necessary part of an amorphous semiconductor thin film is irradiated selectively with a laser beam and is etched and only a polycrystalline part is left by making use of a phenomenon that an etching speed at an amorphous part is faster than at a crystallized part. CONSTITUTION:A passivating film 2 and an amorphous semiconductor thin film 3 are laminated on a substrate 1; only a necessary part is irradiated selectively with a laser beam 4; the amorphous semiconductor thin film 3 is crystallized; a polycrystalline semiconductor thin film 6 is formed. When an etching operation is executed, a part of the amorphous semiconductor thin film whose etching speed is faster than a part of the polycrystalline semiconductor thin film 6 is etched faster; when this does not happen, the etching operation is completed. By this setup, only a part of the polycrystalline semiconductor thin film 6 whose etching speed is slow is left; a polycrystalline semiconductor thin film 8 of a desired pattern is formed. During this process, the polycrystalline semiconductor thin film itself is etched; its film thickness is reduced; the film thickness of the amorphous semiconductor thin film 3 is made thicker in advance in consideration of the film thickness to be reduced.