Nanometer-sized patterning of polysilicon thin films by high density plasma etching

Abstract

Nanometer-sized patterning of polysilicon thin films was performed by a high density inductively coupled plasma (ICP) etching. The etch characteristics of polysilicon thin films with an e-beam resist mask were investigated using Cl 2, C 2F 6, and HBr-based gas mixes. The etch rate, the etch selectivity and the etch profile of polysilicon films were examined as a function of the concentration of each gas, using Ar as a diluent. The Cl 2 gas showed fast etch rate of polysilicon films, and the high selectivity of polysilicon films to resist was obtained in HBr and C 2F 6 gases. The effect of an etch gas on the etch profile of polysilicon thin films was observed using field emission scanning electron microscopy for nanometer-sized patterns. Good nanometer-sized patterning of polysilicon thin films with 60 and 95 nm wide lines has been achieved in HBr/Ar and C 2F 6/Ar plasmas.