Manufacturing and DC characterization of conductive through wafer via for MEMS applications

In this paper we demonstrate a method to manufacture low resistance through wafer interconnections using gold as the conductive layer. 200 μm thick high resistivity (HR) Si wafers were used and 100 μm diameter through wafer via (TWV) were manufactured by dry etching. The conductive layer was manufactured first by depositing TiAu (DC sputtering) on both sides, followed by gold electroplating to reach the desired thickness. Finally, conductive TWV were sealed by using benzocyclobutene removal. DC measurements have shown a resistance of about 48.5 mΩ/via.