Patent ID: 8889544

Claim:
A method of forming a damascene structure on a substrate, comprising: depositing a metal chemical-mechanical polish (CMP) stop layer on the substrate having a dielectric layer on a surface of the substrate, the dielectric layer having a first dielectric constant value, wherein the metal CMP stop layer is a low-k dielectric with a porogen; patterning the substrate to form a damascene opening by etching the dielectric layer; lining the damascene opening with a copper barrier layer; filling the damascene opening with a copper layer, wherein the copper layer is deposited covering the copper barrier layer; performing metal CMP to remove the copper layer and the copper barrier layer outside the damascene opening, wherein the metal CMP stop layer prevents the metal CMP from removing the dielectric layer, and the metal CMP stop layer is uncured; and performing a cure on the metal CMP stop layer to convert or drive out the porogen after performing the metal CMP, wherein the curing is performed in a hydrogen-containing environment, wherein a dielectric constant value of the cured metal CMP stop layer is equal to the first dielectric constant value.