Adapting multichip module foundries for MEMS packaging

Methods of packaging micro-electro-mechanical systems (MEMS) using advanced multichip module (MCM) foundry processes are described. MCM packaging provides an efficient solution for integration of MEMS with other microelectronic technologies. The MCM foundries investigated for MEMS packaging were the General Electric high density interconnect (HDI) and chip-on-flex (COF) processes, as well as the Micro Module Systems (MMS) MCM-D process. Bulk and surface micromachined test die were packaged with CMOS electronics using these MCM foundries. Procedures were developed to successfully release and assemble the MEMS devices without degrading the MCM package or any other die in the module. The use of MCM foundries enables the cost-effective development of microsystems in situations for which monolithic integration of MEMS and microelectronics is not suitable.