Patent ID: 8753981

Claim:
A method for forming tungsten through-silicon vias in a wafer having a semiconductor substrate, a first interlayer dielectric structure over the semiconductor substrate, a metallization structure on the first interlayer dielectric structure, a second interlayer dielectric structure over the first interlayer dielectric structure, and semiconductor components, the method comprising: forming a first opening through the second interlayer dielectric structure to the metallization structure on the first interlayer dielectric structure; forming a second opening through the second interlayer dielectric structure and the first interlayer dielectric structure to one of the semiconductor components; filling the first and second openings with a conductive material, wherein the conductive material in the second opening forms a conductive contact; forming a via opening by etching completely through the second interlayer dielectric structure, completely through the first interlayer dielectric structure, and through only a portion of the semiconductor substrate such that the via opening has a sidewall extending through at least a portion of the semiconductor substrate and a closed end in the semiconductor substrate, wherein the via opening is spaced laterally apart from the conductive contact that is electrically coupled to the one of the semiconductor components; forming a dielectric liner along the sidewall of the via opening by depositing a first portion of a dielectric material over the second interlayer dielectric structure and a second portion of the dielectric material into the via opening, and removing the first portion of the dielectric material from the second interlayer dielectric structure such that the second portion of the dielectric material lines the sidewall of the opening and defines the dielectric liner; forming a tungsten conductor along the dielectric liner by depositing (a) a first portion of the tungsten over the second interlayer dielectric structure such that the first portion of tungsten is in electrical contact with conductive material associated with the conductive contact and (b) a second portion of tungsten defines the tungsten into the via opening such that the second portion of tungsten conforms to the dielectric liner in the via opening and partially fills the via opening, wherein the second portion of tungsten defines the tungsten conductor and a cavity extends into the tungsten conductor; depositing a first portion of polysilicon on the first portion of the tungsten and a second portion of polysilicon that fills the cavity in the tungsten conductor; removing the first portion of polysilicon and the first portion of tungsten such that the tungsten conductor is electrically isolated from the conductive contact.