Device Process Integration: A New Device Fabrication Approach

Microelectromechanical systems (MEMS) devices have gained considerable attention in medical and automotive applications due to their vast advantages in fault detection. However, the cost for MEMS devices has been a challenge for the device manufacturing industry due to the final packaging of the devices. It is considered expensive compared with device fabrication in certain applications. Majority of MEMS devices are still housing traditional packaging methods due to difficulty in handling and yield loss. The advanced interconnect solutions based on thin silicon carrier and through silicon via are being developed to interconnect integrated circuits and other devices at high densities. Can such technologies be used for MEMS device interconnections? It is really a challenge for MEMS designers and engineers due to the MEMS elements present in the devices. In this paper, we present a device fabrication process to realize interconnects that are fabricated prior to the MEMS elements are defined and processed in the device wafer. The interconnects are filled by doped polysilicon and device wafers with such prefabricated vertical interconnects can be used as the starting wafers for any device processing including optoelectronic and MEMS. The process details and their characterization are elaborated along with the physical and electrical analysis of such interconnections.