Low temperature bonding techniques for MEMS devices

Conventional bonding techniques like fusion, glass frit, soldering, eutectic, and anodic bonding, have been used in packaging for micro-electro-mechanical systems (MEMS). These bonding techniques require high temperature which results in bending/buckling of MEMS devices especially in case of hanging structures. In this work, low temperature and low cost bonding techniques with commercially available epoxy 320 NC and photoresist SU-8 2010 are done. Bonding with commercially available epoxy 320 NC at room temperature leads to spreading of epoxy in device region and affects the device performance. To define bonding ring dimensions, photoresist SU 8 2010 is used as an adhesive. Sharp dimensions of SU 8 2010 bonding ring are achieved using lithography. Top silicon cap is fabricated using TMAH etching. The bonds made with these techniques gave good shear strength, as measured with an indigenous setup.