Patent ID: 7189640

Claim:
A method of forming dual damascene structures, comprising: providing a substrate comprising a dielectric layer thereon, the dielectric layer comprising a plurality of via holes; forming a gap filler into each via hole; forming a first anti-reflective coating (ARC) film on the dielectric layer subsequent to forming the gap filler into the via holes; forming a second ARC film on the first ARC film; forming a photoresist pattern on the second ARC film to define a plurality of trenches; performing an etching process to remove the first ARC film, the second ARC film, and an upper part of the dielectric layer not covered by the photoresist pattern to form the trenches; removing the photoresist pattern and the gap fillers after the trenches are formed; and removing the first ARC film and the second ARC film after the photoresist pattern and the gap fillers are removed.