Patent ID: 6846749

Claim:
A method of forming an interconnect structure having a first feature and a second feature, comprising the steps of: (a) providing an article comprising a conductive layer that has a dielectric layer thereon; (b) depositing a first photoresist layer on the dielectric layer; (c) patterning the first photoresist layer to form a first mask pattern defining the first feature; (d) etching the dielectric layer using the first photoresist layer as a mask to form the first feature using an etch chemistry that comprises a member of the group NH 3 , NF 3 and N 2 O; (e) removing the first photoresist; (f) depositing a second photoresist layer on the article; (g) patterning the second photoresist layer to form a second mask pattern defining the second feature; (h) etching the dielectric layer using the second photoresist layer as a mask to form the second feature.