Thank you. I just did it and there were several small regions with foam. I remember when I under exposed su8 rinsing it with IPA caused the whole wafer to be covered with foam. I had no idea why. -----Original Message----- From: mems-talk-bounces+ddimitrov=brooklyn.cuny.edu@memsnet.org on behalf of Matthieu Nannini Sent: Mon 7/7/2014 6:44 PM To: mems-talk@memsnet.org Subject: [mems-talk] Unremoved SU-8 after exposure Quick test: do you rinse the PGMEA with IPA ? If yes, any not cross linked SU8 should react and release a white-ish foam. If it does it means it's crosslinked already in which case you'd have to turn to your exposure method and find out what's wrong. mems-talk-request@memsnet.org a écrit : > Hello, > > I am graduate student in Brooklyn College and I am trying to reinvent the wholeMEMS procedure as I do not have any professional help. My science adviser is from another field. > > I am having difficulties with the developing of SU-8 2025. Here is what I am doing: > > I am spin - coating 4 inch Si or Pyrex wafer to 50 - 60 um thin film > Pre - baking at 96 degrees for 15 min > Sometimes instead I am putting the wafer in the vacuum chamber of my UV imprinter. The vacuum is taking away the solvent and clear most of the bubbles. > UV exposure with a hand made Imprinter: Xenon lamp 22kV at 10 microsec. pulses. Three 30 seconds exposures with couple of seconds pause. > UV lamp creates heat so the wafer is let for 2 - 3 min to relax. > Post bake of 15 min at 95 degrees. > > Developing by tenderly shaking the wafer in a vessel with Propylene glycol monomethyl ether forever. > > The result is that I clearly can see my pattern as exposed SU-8 is yelowish but the unexposed parts are not removed and form thin film with the exposed part. > Less exposure leads to removing all of the polymer. > (This is happening even without any mask but the pattern is formed by metal structure that divides 4 inch wafer into several smaller regions.) > > Can anybody figure out what is my mistake? > > Thank you > Dimitar Dimitrov > > > ------------------------------ _______________________________________________ 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