A Cavity Chip Interconnection Technology for Thick MEMS Chip Integration in MEMS-LSI Multichip Module

We develop a cavity chip interconnection technology for thick microelectromechanical systems (MEMS) chip integration. The cavity chip comprising Cu through-silicon via and Cu beam-lead wire was fabricated by micromachining processes. The cavity chip could easily connect a thick MEMS chip with a high step height of more than a few hundred micrometers without changing the circuit design of MEMS chip and complicated extra process. Fundamental characteristics are successfully obtained from a pressure-sensing MEMS chip of 360- thickness, where the MEMS chip was connected to a Si substrate by the cavity chip without degrading brittle sensing elements. This interconnection technology would provide a good solution for thick MEMS chip integration with high flexibility.