Thermo-mechanical simulations of RF-MEMS 0-level package based on wafer bonding by soldering

Abstract

Models and results are presented of thermomechanical simulations of an RF-MEMS 0-level package based on wafer bonding by soldering. For moderate realistic loads most relevant responses are accetable. However, residual stress and thermal expansion of the solder material lead to deformations beyond the yield strain in corners of solder cross sections. This phenomenon can only be addressed by technology modifications, not by design. A 1 bar hydrostatic pressure aggravates this issue slightly. This addition can be addressed by design modifications. A hydrostatic pressure of 90 bar necessitates large design modifications, in particular a dense array of pillars.