Hello, There is still some solvent in the unexposed SU-8. So during the soft-bake (and the post-exposure bake) we observed a strong outgassing. (don't know what kind of gas) We made some experiments to perform the soft-bake on a hot-plate with a top cover. The Su-8 remained soft and gluey even after 1 hour. So I think, the gold cover prevents the outgassing, leading to the destruction of the surface. Good look with your experiments Christoph Friese ____________________________________________ Dipl.-Ing. Christoph Friese IMTEK - Laboratory for micro-optics Georges-Koehler-Allee 102 D-79110 Freiburg Germany Tel.: ++49 761 203-7575/7566 Fax.: ++49 761 203-7562 Mail: friese@imtek.de Web : http://www.imtek.de/micro-optics/ ____________________________________________ > -----Ursprüngliche Nachricht----- > Von: Anthony Holland [mailto:anthony.holland@rmit.edu.au] > Gesendet: Samstag, 10. April 2004 02:28 > An: mems-talk@memsnet.org; leidongmao@yahoo.com > Betreff: Re: [mems-talk] SU-8 wrinkles after bake > > > the wrinkling may be due to the glass transition temperature > being too low. I have observed this problem with aluminium on > other polymer films. I understand that a higher baking > temperature before metal deposition can increase the glass > transition temperature in some polymers and hence prevent the > surface flowing, causing wrinkles in a subsequent heat process. > > I noted that the wrinkling did not occur when there was no > metal, irrespective of the heat processes. Can anyone explain this? > > Good luck > > Anthony Holland > > > > Dr. Anthony Holland > Research Fellow > Australian Photonics Cooperative Research Centre > School of Electrical and Computer Systems Engineering > RMIT University > GPO Box 2476V > Melbourne > VIC 3000 > AUSTRALIA > > Tel. 61 3 9925 2150 > Fax. 61 3 9925 2007 > >>> leidongmao@yahoo.com 04/10/04 3:50 AM >>> > Hello all, > > We met a SU-8 wrinkle problem and would like to > hear any suggestion. The process is to pattern gold on > the un-exposed SU-8 resist. We first piranha etched > the glass slides and baked it for 1hr@200C. The > spun-on SU-8 resist looked good after soft bake. Then > gold was sputtered onto the resist, and it was > patterned by using Shipley 1813 positive resist. After > that, the gold was etched in Transene gold etchant TFA > (a complex of KI/I2), rinsed in DI water, baked at 90C > for 30 mins. The wrinkles showed up during the baking. > Does anyone have the same experience? Any suggestion > welcomed. > > > __________________________________ > Do you Yahoo!? > Yahoo! Small Business $15K Web Design Giveaway > http://promotions.yahoo.com/design_giveaway/ > > _______________________________________________ > 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/