POLYMETAL GATE ELECTRODE HAVING STRESS BUFFER LAYER INSERTED FOR REDUCING FILM STRESS OF GATE STACK AND FABRICATING METHOD THEREOF

摘要

PURPOSE: A polymetal gate electrode having a stress buffer layer and a fabricating method thereof are provided to reduce film stress generated from a hardmask and stress generated from a post thermal process by inserting the stress buffer layer into an intermediate part of a polysilicon layer. CONSTITUTION: A gate insulating layer(302) is formed on a semiconductor substrate(301). A gate stack(300) is formed on the gate insulating layer. The gate stack includes a polysilicon layer(303,305) as a bottom layer, a hardmask insulating layer(308) as a top layer, and a metal layer(307) formed therebetween. A stress buffer layer(304) is inserted into an intermediate part of the polysilicon layer.