Composite barrier/etch stop layer comprising oxygen doped SiC and SiC for interconnect structures

摘要

A dual damascene structure comprising a composite barrier/etch stop layer including a lower silicon carbide (SiC) layer and an upper first oxygen doped SiC layer formed over a substrate is provided. A first dielectric layer is formed over the first oxygen doped SiC layer followed by a second oxygen doped SiC etch stop layer, and a second dielectric layer. An opening with a via and an overlying trench extends through the second dielectric layer, the second oxygen doped SiC etch stop layer, the first dielectric layer, the upper first oxygen doped SiC layer and at least a portion of the lower silicon carbide (SiC) layer. The opening is filled with a diffusion barrier layer and a metal layer.