Patent ID: 8048325

Claim:
A method of smoothing a sidewall in a multilayer mask on a substrate in a plasma processing system comprising: forming a multilayer mask on said substrate, said multilayer mask comprising a light-sensitive layer overlying an anti-reflective coating (ARC) layer; forming a pattern in said light-sensitive layer using a lithography technique; transferring said pattern to said anti-reflective coating (ARC) layer by performing the following in a plasma processing system: introducing a process gas comprising one or more gasses collectively containing ammonia (NH 3 ), and a passivation gas; forming a plasma from said process gas in said plasma processing system; and exposing said substrate to said plasma; and forming of a passivation film on said sidewall of said multilayer mask prior to transferring said pattern in said multilayer mask to any underlying thin film in order to smooth surface roughness of said sidewall of at least said light-sensitive layer or said anti-reflective coating (ARC) layer.