Polymer MEMS processing for multi-user applications

Abstract

We have developed a new polymer MEMS process that shows enormous flexibility in design parameters. This process uses entirely spin-on layers for structural and sacrificial materials. Further, this process flow is designed for multiple users to fabricate as many devices as possible on the same wafer which up to this point has not been demonstrated with polymer MEMS technologies. In this process, all structural layers are fabricated out of negative tone SU-8 photoresist and all sacrificial and separation layers are defined by a thin film of polystyrene. Using entirely spin-on layers for structural and sacrificial materials provides an easy way to select layer thicknesses without having to significantly alter the materials or processing techniques. A metal thin-film deposition step is also incorporated that allows electrical connection to the microstructures and actuators in this process. To characterize the robustness and flexibility of this technology we have fabricated a variety of in-plane and out-of-plane microstructures including chevron-type thermal actuators and tested their mechanical and electromechanical operation. The entire process sequence is accomplished at temperatures below 200 °C, making this technology compatible for post-processing integration of MEMS on an electronics circuit wafer.