Application of hipims to through silicon via metallization in three-dimensional wafer packaging

Abstract

A method of magnetically enhanced sputtering an electrically-conductive material onto interior surfaces of a trench described herein includes providing a magnetic field adjacent to a target formed at least in part from the electrically-conductive material, and applying a DC voltage between an anode and the target as a plurality of pulses. A high-frequency signal is applied to the pedestal supporting the semiconductor substrate to generate a self-bias field adjacent to the semiconductor substrate. The high-frequency signal is applied to the pedestal in pulses, during periods of time that overlap with the periods during which the DC voltage pulses are applied. The periods of time that the high-frequency signals are applied include a duration that extends beyond termination of the DC voltage pulse applied between the anode and the target. During each DC voltage pulse the electrically-conductive material is sputter deposited onto the side walls of the trench formed in the semiconductor substrate.