Adhesion problem usually result from under-exposure and incomplete baking. Try increasing exposure time and baking time than seen in Microchem manual. When you say the SU8 pattern is not uniform, do you mean the spin-coating is not uniform? If so, spinning the wafer right away after pouring the SU-8 can rid the dent that may appear at the pouring site. Not sure if Octyltrichlorosilane is better than Sigmacote, but our lab uses it to separate ~1cm thick PDMS from SU-8 patterned silicon wafer. Maybe you could consider as an option. Good luck! On Sun, Feb 23, 2014 at 6:38 PM, Sebastian R Freeman < sfreema1@binghamton.edu> wrote: > Hello everyone, > > I am a graduate student making microfluidic devices for the first time. I > am processing SU-8 2050 negative photoresist on a silicon wafer to try and > produce a porous PDMS membrane. My difficulty lies in producing the the > SU-8 structures. I have been having adhesion problems, as well as getting > my structures to develop uniformly. The pattern I am trying to make is > composed of an array of tiny cylindrical posts 50 micros high, with a > diameter of approximately 5 microns, and spaced 15 microns apart from each > other. > > The PDMS spin coating is also creating difficulties. When I attempt to peel > off the PDMS from the SU-8, the PDMS rips off my posts. I have applied > Sigmacote as I was told this would lessen the adhesion between PDMS and > SU-8, but it appears to have only helped minimally. > > If anyone has any good advice or suggestions of new approaches, I would be > most appreciative. Thank you. > _______________________________________________ > Hosted by the MEMS and Nanotechnology Exchange, the country's leading > provider of MEMS and Nanotechnology design and fabrication services. > Visit us at http://www.mems-exchange.org > > Want to advertise to this community? See http://www.memsnet.org > > To unsubscribe: > http://mail.mems-exchange.org/mailman/listinfo/mems-talk > _______________________________________________ Hosted by the MEMS and Nanotechnology Exchange, the country's leading provider of MEMS and Nanotechnology design and fabrication services. Visit us at http://www.mems-exchange.org Want to advertise to this community? See http://www.memsnet.org To unsubscribe: http://mail.mems-exchange.org/mailman/listinfo/mems-talk