Dry etching method

Abstract

Abstract PURPOSE:To enable to perform an anisotropic etching on a polysilicon film while maintaining a large selectivity ratio against the under layer oxide film and photoresist by a method wherein a dry etching is performed using CCl2F2 gas wherein N2 gas is mixed. CONSTITUTION:A reactive ion etching process is performed on the polysilicon film 201, having a photoresist 204 as an etching mask, located on a silicon oxide film 203 grown on a silicon wafer 202. An etching is performed using the mixture of CCl2F2 gas and N2 gas. Consequently, an anisotropic etching, wherein undercut is not generated at all on the interface 205 of the polysilicon film 201 and the silicon oxide film 203, can be performed. It is desirable that the mixing quantity of N2 gas is set within the range of 5-80% in the flow rate of the total quantity of flow of CCl2F2 gas and N2 gas.

Inventors

• 👤 Tsutomu Tsukada
• 👤 勉 塚田
• 👤 Hideki Takahashi
• 👤 高橋　秀輝

Bibliographic Details