Influence of Etch Gas on High Density Plasma Etching of Polysilicon Thin Films with Nanometer-Size Patterns

Abstract

High density plasma etching of polysilicon thin films with nanometer-size patterns was performed in an inductively coupled plasma. The etch process of polysilicon films with a photoresist mask was characterized using Cl 2 , C 2 F 6 , and HBr gas chemistries in terms of etch rate, etch selectivity, and etch profile. The fast etch rate of polysilicon films was obtained in Cl 2 /Ar gas and the high selectivity of polysilicon to photoresist was found in HBr/Ar gas mixture. The etching of polysilicon films masked by photoresist with nanometer-size patterns was attempted with various etch gases, and an anisotropic etching of 60 nm sized pattern was achieved in HBr/Ar and C 2 F 6 /Ar plasmas.