Low temperature epoxy bonding for wafer level MEMS packaging

In this paper, we report on a technology for wafer-level MEMS packaging with vertical via holes and low temperature bonding using a patternable B stage epoxy. We fabricated via holes for vertical feed-throughs and then applied bottom-up copper electroplating to fill the via holes. For low temperature wafer level packaging, we used B-stage epoxy bonding in the sealing line. The optimal bonding parameters were 150 °C and 30 min. The tensile strength was about 15 MPa. Therefore, this packaging technology can be used for low temperature wafer level packaging for many MEMS devices.