Process development of negative tone dry film photoresist for MEMS applications

Applications of dry film photoresists in MEMS (micro-electro-mechanical systems) products are expected, since dry film photoresists have numerous advantages such as easily to be laminated and removed after processing. This paper reports on the process study of fabricating microstructures using commercially available dry film photoresists. Single layer and multi-lever laminations were performed; lateral resolutions of patterned trenches, and sidewall verticality were investigated. Trenches of 12 m wide were successfully patterned and sidewalls with 90 /-I verticality were achieved. Furthermore, dry film photoresists were laminated successfully on a nonplanar wafer with previously etched V-grooves for the next-step fabrication. The results demonstrated new possibilities of dry film photoresist for MEMS applications.