Adhesive wafer bonding of micro-actuators with SU-8 photoresist

Abstract

Adhesive wafer bonding of micro-actuators using SU-8 photoresist is reported. It was investigated in this study that the bonding temperature, bonding pressure, baking time and thickness of the cross-linked SU-8 photoresist layer affects the bonding strength of the assembled micro-actuators. The adhesive wafer bonding was performed by applying different pressures while baking the wafers at different temperatures. In this work, we have demonstrated that decreasing the exposure dose and post-exposure baking temperature play significant roles in affecting the bonding strength of assembled micro-actuators. We believe that lowering the exposure dose and post-exposure temperature will inhibit hardening of the intermediate negative photo-resist layer, and it enhances softening of SU-8 thin film, which can facilitate the bonding strength between the micro-chips.