New fluorocarbon free chemistry proposed as solution to limit porous SiOCH film modification during etching

Today porous SiOCH combined with metallic hard masking strategy is an integration of choice for advanced BEOL interconnect technology node. However in this context the main integration issue is the dielectric film sensitivity to fluorocarbon (FC) etch chemistry. In this study, new FC free etching chemistry has been proposed as breakthrough solution. Based on pattern and blanket film analyses, the benefits of this new chemistry is presented and discussed with respect to conventional FC etching. Its compatibility with metallic hard mask integration and wet cleaning is also evaluated.