Effect of fluorinated plasma on SiLK during mineral hard masks etching

Abstract

This paper concerns the integration of low-k dielectric SiLK as interconnect insulator with copper metallization. It describes more particularly the impact of hard mask etching on SiLK. It was verified that fluorine based plasma transforms surface of SiLK into fluorinated polymer with interesting properties: organic solvent solutions do not penetrate this layer. However, during the etching step, it was observed that fluorine could physically diffuse into the SiLK volume. This fluorine can be easily removed using a basic aqueous solution.