Patent ID: 8293625

Claim:
A method of forming a device, comprising: providing a semiconductor-on-insulator (SOI) substrate having a top SOI layer, a middle BOX layer and a bottom substrate layer; depositing a hard mask layer on the SOI substrate; forming a trench in the SOI substrate, wherein the trench extends into the substrate layer; depositing a blocking layer on a top surface of the hard mask layer and on a bottom and sidewalls of the trench; removing a portion of the blocking layer above the hard mask layer and on the bottom of the trench; removing the hard mask layer; removing the remaining portion of the blocking layer on the sidewalls of the trench; depositing a first conductive material to fill the trench; planarizing the first conductive material; and removing a portion of the first conductive material from the trench, wherein a top surface of the first conductive material is below a bottom surface of the SOI layer and above a top surface of the substrate layer.