Fabrication of Carbon Nanotube filled blind vias and the investigation of Carbon Nanotubes embedded in a copper matrix for three-dimensional chip stacking applications
Through silicon vias (TSVs) have been studied extensively because of their ability to increase the performance of electronic systems. Ultimately the performance of the TSVs depends on the materials used to fill them. Current technologies depend on filling the TSVs with copper. Carbon Nanotubes (CNTs) offer superior material properties to copper and have been investigated as a replacement for the metal in many applications. We studied a method of forming the blind vias and growing CNTs within the blind vias using a chemical vapor deposition process. Current techniques for growing CNTs to use as interconnects are unsatisfactory because of their low CNT density and the inability to support the as-grown CNT bundles during a planarization process. As a solution to these issues, we have investigated the formation of a CNT/Cu composite material. Various materials were used to grow the CNTs and then deposit copper using electroplating. The ability of the as-grown CNT columns to be densifed before the electroplating step has also been studied.