Patent ID: 6913994

Claim:
A dual damascene method, comprising: (a) providing a substrate with a stack of layers formed thereon, said stack comprising a bottom cap layer and an upper organosilicate glass (OSG) dielectric layer; (b) coating a photoresist layer on said stack and patterning to form a via hole in said photoresist; (c) transferring said via hole through said OSG layer with a plasma etch process; (d) removing said bottom cap layer exposed by said via hole; (e) removing said photoresist by a soft etch process; (f) forming a planarizing bottom anti-reflective coating (BARC) on said stack and in said via hole and patterning a trench in a photoresist layer on said planarizing BARC, said trench is aligned above said via hole; (g) transferring said trench into said OSG dielectric layer; (h) removing said planarizing BARC and said photoresist by a soft etch process; and (i) depositing a barrier metal liner on the sidewalls and bottom of said trench and via hole and then filling said trench and via with a metal.