Patent ID: 7749563

Claim:
A method for processing a substrate, comprising: forming a barrier layer in a dual damascene structure, wherein the barrier layer is directly formed on a substrate surface comprising metal features, and the forming comprises: depositing a silicon carbide barrier layer on the substrate by introducing a first processing gas mixture comprising dimethylphenylsilane and a nitrogen containing compound into a processing chamber, and reacting the first processing gas mixture to deposit the silicon carbide barrier layer, wherein the silicon carbide barrier layer has a dielectric constant of less than 4; and depositing a silicon carbide cap layer directly on the silicon carbide barrier layer by introducing a second processing gas mixture comprising trimethylsilane into the processing chamber, and reacting the second processing gas mixture to deposit the silicon carbide cap layer in the processing chamber, wherein the silicon carbide cap layer has a thickness between about 50 Å to about 100 Å.