Patent ID: 7390753

Claim:
A method of strengthening and enhancing selectivity of a photoresist mask including removing photoresist mask sidewall striations, comprising: providing a substrate having a feature layer on said substrate and a photoresist layer on a bottom anti-reflective coating layer above said feature layer; forming a photoresist mask in said photoresist layer by exposing said photoresist layer to a light source and developing said photoresist layer; exposing said photoresist mask to a first photoresist-strengthening plasma including partially removing said sidewall striations; etching through said bottom anti-reflective coating layer in a separate etching step; exposing said photoresist mask to a second photoresist-strengthening plasma following said etching through said bottom anti-reflective coating, said second photoresist-strengthening plasma further smoothing said sidewalls to remove said sidewall striations; and, etching said feature layer according to said photoresist mask.