Patent ID: 8563432

Claim:
A method for forming a through-silicon-via (TSV) structure, the method comprising: providing a silicon substrate; forming an interlayer dielectric layer on the silicon substrate; forming a hard mask structure on the interlayer dielectric layer, the hard mask structure including a first hard mask layer overlying the interlayer dielectric layer, and a second hard mask layer overlaying the first hard mask layer, wherein the first hard mask layer is made of at least one material including a metal element; forming an opening through the hard mask structure and the interlayer dielectric layer, the opening having a bottom and sidewalls in the silicon substrate; depositing an insulating layer on the second hard mask that is on the first hard mask layer of the hard mask structure and on the bottom and the sidewalls of the opening; removing a portion of the insulating layer from the second hard mask layer and removing the second hard mask layer from the first hard mask layer to expose the first hard mask layer; filling a conductive material into the opening; and removing the conductive material and the first hard mask layer by a CMP process until the interlayer dielectric layer is exposed.