Patent ID: 8119522

Claim:
A method, comprising: (a) forming a wire in a first dielectric layer on a substrate; after (a), (b) forming a dielectric barrier layer over said wire and said first dielectric layer; after (b), (c) forming a second dielectric layer over said barrier layer; after (c), (d) forming a patterned photoresist layer on a top surface of said second dielectric layer; after (d), (e) with said patterned photoresist layer in place, performing a first reactive ion etch to etch a trench through said second dielectric layer and not through said barrier layer; after (e), (f) with said patterned photoresist layer in place, performing a second reactive ion etch to extend said trench through said barrier layer; and after (f), (g) removing said patterned photoresist layer using a reducing plasma or a non-oxidizing plasma.