Patent ID: 6844143

Claim:
A method of forming the self-aligned dual damascene opening of a dual damascene structure, comprising the steps of: providing a substrate having a dielectric layer thereon; forming a first photoresist layer over the dielectric layer; forming a non-photosensitive material layer over the first photoresist layer, wherein the non-photosensitive material layer includes an anti-reflection layer and a material of the anti-reflection layer is selected from the group consisting of addition polymerization polymer, condensation polymerization polymer and ring-opening polymerization polymer; forming a second photoresist layer over the non-photosensitive material layer; conducting a first photo-exposure of the second photoresist layer; conducting a first photoresist development to pattern the second photoresist layer and the non-photosensitive material layer and form a trench; conducting a second photo-exposure of the first photoresist layer; conducting a second photoresist development to pattern the first photoresist layer and form a via opening underneath the trench, wherein the trench and the via opening together constitute a dual damascene opening pattern; and conducting single etching operation to transfer the dual damascene opening pattern to the dielectric layer using the patterned first photoresist layer, the patterned non-photosensitive layer and the patterned second photoresist layer as an etching mask, thereby forming a dual damascene opening in the dielectric layer.