Dry mechanical liftoff technology for metallization on parylene-C using SU-8

This paper presents a new fabrication method to employ dry mechanical liftoff of SU-8 mask to pattern metals on parylene-C film. Soaking tests were done to examine the adhesion between SU-8 and parylene-C film with different interface treatments. SU-8 masks with different thickness were tested in order to find out the best trade-off between the feature sizes and the easiness of removal from paryelene-C film after metal deposition. Features from 10 μm to 300 μm in diameter and width were successfully patterned on parylene-C film by this method. The 15 μm thick SU-8 liftoff mask is highly flexible and can be peeled off mechanically from parylene-C film by tweezers seconds without any visible residue. Metal lines with testing pads from 10 μm to 100 μm wide and 1 cm long were also fabricated and tested to evaluate their resistances. this new method provides an alternative way of metallization on parylene-C film which benefits the application in MEMS area.