Releasing SU-8 structures using polystyrene as a sacrificial material

We have successfully developed a new method to release SU-8 structures with polystyrene as a sacrificial material. Toluene is initially used to dissolve solid polystyrene, and the resulting solution is employed to spin coat a sacrificial polystyrene layer onto a glass plate prior to SU-8 deposition. Toluene is used again at the end of the process to sacrificially etch the polystyrene layer to release the cured SU-8 structures. Toluene has no effect on the cured SU-8, even with significant over-etch times, and the dissolution and etch rates are relatively fast. Using this method, we have successfully released SU-8 membranes of an area of 50 cm(2). (C) 2004 Elsevier B.V. All rights reserved.