Method of forming an oxide film on a gate side wall of a gate structure

摘要

In order to prevent abnormal oxidation of the side wall of a polycide gate conductor layer in the oxidation heat treatment process after the RIE processing of the polycide gate conductor layer in a semiconductor memory cell, the heat treatment for oxidizing the side wall of the polycide gate conductor layer is conducted in two steps with different conditions. By conducting the first heat treatment process in an inert atmosphere, a thin oxide film is formed on the side wall of the polycide tungsten/gate conductor layer. Then by conducting the second heat treatment process in an atmosphere with a strong oxidizing property, a thick oxide film without abnormal oxidation can be formed.