Direct Al–Al contact using low temperature wafer bonding for integrating MEMS and CMOS devices

This paper investigates the feasibility of direct Al–Al contact using low temperature wafer bonding process for the integration of MEMS and CMOS devices. Sufficient mechanical strength oxide–oxide bonds can be achieved using an oxygen plasma assisted low temperature wafer bonding process, with Al structures present on the bonding surface. An average contact resistance of 2.6×10−8Ωcm2 was measured from single contact test structures, indicating that the establishment of direct Al–Al interconnect during the bond anneal step is possible.