Ning, The manufacturer does provide a SU-8 that is able to get to those thickness that you specified. You will have to call the company and request the material as it is not yet comercially avalible. Good luck. Bruce ________________________________ From: mems-talk-bounces@memsnet.org on behalf of nwu Sent: Mon 2006.07.17 14:24 To: mems-talk@memsnet.org Subject: [mems-talk] Spin coating very thin PDMS film I am wondering how to spin coating a very thin and uniform layer of PDMS on silicon surface. The thickness is about 150 - 300 nm. What kind of solvent should I choose? I used hexane before, but it does not give me uniform surface during spin coating. Thanks Ning