Indirect removal of SU-8 photoresist using PDMS technique

SU-8 photoresist shows superior images for thick film lithography and has been utilized as an electroplating mold. However, crosslinked SU-8 is difficult to remove reliably from high-aspect-ratio microstructures (HARMs) without damage or alteration to the electroplated metal. In this paper, an indirect SU-8 removal method is proposed. Instead of directly using SU-8 microstructure as the electroplating mold, a polydimethysiloxane (PDMS) replica is employed. The metallic micromold insert obtained through this method can be easily peeled off from the PDMS replica, meanwhile with high resolution and smooth surfaces.