High-Density Solder Bump Interconnect for MEMS Hybrid Integration

An ultra high-density hybrid integration for micro-electromechanical system (MEMS) mirror chips with several thousand inputs/outputs has been developed. The integration scheme involving flip-chip assembly provides electrical signal to individual mirrors, which is compatible with postprocessing steps of selectively removing the silicon handle and releasing the MEMS mirrors. For the first time, to our knowledge, solder deposition and flip-chip bonding of 3-mum bumps on 5-mum centers of a large array has been demonstrated.