Applying SU-8™ to the fabrication of micro electro discharge machining electrodes

Taking advantage of high aspect ratio micro structure technology (HARMST) allows a cost competitive approach to batch fabricate a high number of tool electrodes for micro electro discharge machining (EDM). A new type of EDM tool micro electrode fabrication was developed using a combination of near UV lithography to directly polymerize a micromold made of SU-8™ in combination with electroplating. Applying SU-8™ for the fabrication of deep hollow micromolds, an ultra-thin resist film remains on the seed layer at the bottom of the micromolds. This remaining undeveloped resist film at the bottom of the mold prevents the electro deposition on the conductive seed layer. The PVA Tepla PS4008 plasma ashing system was investigated to remove the resist residually from the SU-8™ micromolds before electroplating without destroying the micromold itself and to remove the entire micromold after the fabrication of the micro electrodes selectively.