New methods to assemble, integrate, and package micro devices are always needed in attempts to simplify and expedite fabrication methods to maximize throughput. Our paper focuses on assessing SU-8 as a viable material for packaging and flip chip bonding processes for MEMS and micro devices. In this paper, we vary the level of cross- linking through post exposure bake (PEB) times and assess rectangular ring test structures bonding strength following flip chip bonding through applied tensile loads. In addition, we performed initial assessments on the etching resiliency of varied cross-linking of SU-8. From initial results, the bonding strength is maximized following a 3-min PEB. Cross-linking appears to have minimal effects on SU-8's etch resiliency as all tested samples etched approximately 1.25 μm. From our initial results, SU-8 appears to be a viable and inexpensive material for wafer bonding, assembling and packaging MEMS devices.
Glauvitz, N. E., Starman, L. A., Coutu, R. A., & Johnston, R. L. (2011). Effects of SU-8 cross-linking on flip-chip bond strength when assembling and packaging MEMS. Procedia Engineering, 25, 471–474. https://doi.org/10.1016/j.proeng.2011.12.117