An interconnect structure has a dielectric layer having a dielectric constant less than 3.9 overlying a substrate with a conductive region, a silicon oxycarbide layer overlying the dielectric layer, and a silicon oxynitride layer overlying the silicon oxycarbide layer. A conductive layer is inlaid the silicon oxynitride layer, the silicon oxycarbide layer and the dielectric layer to electrically connect to the conductive region.