Through-substrate via formation with improved topography control

摘要

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.

主权项

1. A method comprising:
forming an interconnect structure over a semiconductor substrate, wherein the interconnect structure comprises an inter-layer dielectric (ILD) and an inter-metal dielectric (IMD) over the ILD; forming a first opening extending a first depth through the interconnect structure and into the semiconductor substrate; forming a second opening contiguous with and wider than the first opening and extending a second depth into the interconnect structure, wherein the second depth is smaller than the first depth; and filling the first opening and the second opening with a metallic material to form a conductive plug having a substantially planar surface at a top of the second opening.