Abstract: A novel plasma process is introduced as an improvement over conventional plasma processes during formation of spacers for FinFET devices. Under this novel plasma process, an oxide layer is grown over sidewall materials and low energy plasma gas is used for the over-etching of the corner areas of the sidewalls. The oxide layer can effectively protect the sidewall materials during the over-etching by the low energy plasma gas and thus to reduce the aforementioned CD losses introduced by the low energy plasma gas. This improved low energy plasma etching technique can protect the fin structure from CD losses as compared to the conventional low energy plasma process, and also avoid damaging fin silicon structure with reduced Si losses as compared to the conventional high energy plasma process.

Abstract: A novel plasma process is introduced as an improvement over conventional plasma processes during formation of spacers for FinFET devices. Under this novel plasma process, an oxide layer is grown over sidewall materials and low energy plasma gas is used for the over-etching of the corner areas of the sidewalls. The oxide layer can effectively protect the sidewall materials during the over-etching by the low energy plasma gas and thus to reduce the aforementioned CD losses introduced by the low energy plasma gas. This improved low energy plasma etching technique can protect the fin structure from CD losses as compared to the conventional low energy plasma process, and also avoid damaging fin silicon structure with reduced Si losses as compared to the conventional high energy plasma process.