Effects of Si on Plasma Etching of Al–Cu–Si Alloy Films

Abstract

The effect of Si content in the Al–Cu alloy VLSI conductor film on the side etching of fine patterns during plasma etching is described. The addition of Si decreases the critical dimension loss. The side etching mechanism of Al alloy fine patterns is discussed and related to the electron transfer properties of the surface aluminum oxides. The surface oxide films are characterized by photoelectrochemical methods and that of Al–Cu has found to show P-type semiconductor properties. The addition of Si to Al–Cu decreases the electron transfer probability of the surface oxide films. A new model on the side etching mechanism which is related to the surface aluminum oxides structure of Al–Cu and Al–Cu–Si films is proposed.