Andreas, there is a poly-isoprene resist from Transene that is stable in KOH solutions. http://transene.com/pkp/ -----Original Message----- From: Andreas K. Huettel [mailto:andreas.huettel@physik.uni-regensburg.de] Sent: Saturday, May 6, 2017 7:42 PM To: General MEMS discussionCc: alexander.albang@physik.uni-regensburg.de Subject: [mems-talk] Wet-etching Si, while a niobium film is protected Dear all, we need to etch deep holes into a Si wafer (with a 500nm surface oxide) that already has sensitive Nb structures on top. The etching alone works mostly fine with first RIE through the oxide and then hot KOH. However, the KOH also dissolves our photoresist and then attacks the niobium. We already tried placing a baked-out PMMA layer between niobium and photoresist, but that didn't help too much. Do you have any advice for this? Are there any photoresists around that are KOH-stable? What other protective could be used that later are easily removed? Best, Andreas -- PD Dr. Andreas K. Huettel Institute for Experimental and Applied Physics University of Regensburg 93040 Regensburg Germany tel. +49 151 241 67748 (mobile) tel. +49 941 943 1618 (office) fax +49 941 943 1670 e-mail andreas.huettel@ur.de http://www.akhuettel.de/ http://www.physik.uni-r.de/forschung/huettel/ _______________________________________________ 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