Hi Melissa, We also bake before spinning 200C for 30 min. Are you using a hotplate or an oven to soft-bake? If you are using an oven, the resist will sometimes solidify on top leaving the bottom still swimming in solvent. Using a hotplate bakes from the bottom first. Also, make sure that you are filtering out wavelengths of light below 360 on your exposure. That can also cause your problem. I've never had any luck with adhesion layers for SU-8 on Si, but I've always gotten the SU-8 itself to adhere. Greg Reimann Boston University -----Original Message----- From: mems-talk-bounces+gjreiman=bu.edu@memsnet.org [mailto:mems-talk-bounces+gjreiman=bu.edu@memsnet.org] On Behalf Of Karin Buchholz Sent: Wednesday, February 11, 2004 12:27 PM To: General MEMS discussion Subject: Re: [mems-talk] SU-8 adhesion problem Hello Melissa, Usually the adhesion of any resist is much better when the samples are dry. So try putting them in an oven (we use 90degree) for 15 min before applying the resist, this will remove the condensed water from the surface. HMDS usually also helps. (we use 10s 3000rpm, but this should not make much difference) Good luck, Karin tailing@dso.org.sg wrote: > Hi, > Am trying to spin about 3-5 um of SU-8 onto a silicon wafer but was getting > some problems of adhesion and the SU-8 came off during the development step. I > read on this discussion group that HMDS was recommended to help with the > adhesion of thicker layers of SU-8. I tried spinning HMDS ar 5000 rpm/30 sec > before spin-coating the SU-8. However, during the pre-bake step (95 degrees > for 2 min), the layer of SU-8 shrunk from the edges of the wafer. What is the > reason for this and how can I prevent it if I want to use HMDS to aid SU-8 > adhesion? Thanking you in advance. > > Regards, > Melissa > -- Dipl.-Ing. Karin Buchholz Walter Schottky Institut Technische Universitaet Muenchen _______________________________________________ MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk Hosted by the MEMS Exchange, providers of MEMS processing services. Visit us at http://www.memsnet.org/