Patent ID: 7056821

Claim:
A method for manufacturing dual damascene structure with a trench formed first, comprising the steps of: providing a substrate having a plurality of semiconductor devices; forming a first metal layer on the substrate; forming a first etching stop layer on the first metal layer; forming a dielectric layer on the first etching stop layer; forming a second etching stop layer on the dielectric layer; forming a first patterned photoresist layer on the second etching stop layer; forming a trench by etching though the second etching stop layer and stopping in the dielectric layer at a predetermined depth; filling with a sacrificial layer into the trench; planarizing the sacrificial layer; forming a second patterned photoresist layer on the sacrificial layer; forming a via by etching the sacrificial layer and the dielectric layer; removing the sacrificial layer and the second patterned photoresist layer; etching the first etching stop layer to expose the first metal layer; filling with a second metal layer; and planarizing the second metal layer.