TW430886B - Method for making semiconductor device with small-sized gate structure - Google Patents

Abstract

A method for making a semiconductor device with a small-sized gate structure comprises two steps of spacer etching. The method comprises forming a gate oxide on the surface of a semiconductor substrate; forming a polysilicon layer on the gate oxide; forming a photoresist layer on the polysilicon layer; using the photoresist layer to define a location of the gate; anisotropically etching the photoresist layer, a portion of the polysilicon layer and the gate oxide; forming a first dielectric layer on the surface of the semiconductor substrate and the surface of the periphery of the polysilicon layer; forming a second dielectric layer on the first dielectric layer; anisotropically etching the second dielectric layer to form a first spacer on the sidewall of the gate; forming a third dielectric layer on the first spacer and the first dielectric layer; anisotropically etching the third dielectric layer to form a second spacer of the gate sidewall; and etching back to make the height of the first spacer and the second spacer lower than the height of the gate structure.