You could try a 'Piranha cleaning'. This mixture is know for its voracious ability to remove organics, so it might help solve your problem. Typically, mixtures of 98% H2SO4 (sulfuric acid) and 30% H2O2 (hydrogen peroxide) in volume ratios of 2-4:1 are used at temperatures of 100?C and higher. Regards, Jason Viotty ___________________________________________________________ Jason Viotty Senior Process Engineer C2V http://www.c2v.nl -----Original Message----- From: anupama@ee.washington.edu [mailto:anupama@ee.washington.edu] Sent: Thursday, April 03, 2003 8:14 PM To: mems-talk@memsnet.org Subject: [mems-talk] C4F8 etchant Hi MEMS Community, I would like to know if anyone knows of a chemical that would etch C4F8 (octofluorocyclobutane) During the DRIE process, C4F8 is deposited for sidewall passivation and mask protection in the alternate deposit and etch cycles. After the DRIE I remove the photoresist AZ4620 by putting the wafers in a Barell Asher with O2 plasma (40mTorr, 300 Watts for 10mins) and subsequent treatment with resist strips EKC for 10 mins at 60C and AZ300T for 10 mins at 75C. This I believe should remove the C4F8 deposits as well. However from our SEM pictures we find that, possibly the unremoved C4F8 acts as a mask for further Silicon etching (in RIE)and this mask is undercut resulting in the loss of our structures. I would appreciate very much if someone on the list could get back to be with an idea of how to strip the C4F8. Sincerely Anupama Anupama V. Govindarajan Graduate Student - EE MEMS laboratory Department of Electrical Engineering University of Washington Campus Box 352500, Seattle WA 98195 Phone: (206)-221-5340 email: anupama@ee.washington.edu _______________________________________________ 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/