US Patent 9418933 Through-substrate via formation with improved topography control

A device include a substrate and an interconnect structure over the substrate. The interconnect structure comprising an inter-layer dielectric (ILD) and a first inter-metal dielectric (IMD) formed over the ILD. A through-substrate via (TSV) is formed at the IMD extending a first depth through the interconnect structure into the substrate. A metallic pad is formed at the IMD adjoining the TSV and extending a second depth into the interconnect structure, wherein the second depth is less than the first depth. Connections to the TSV are made through the metallic pad.