One obnoxious quality of postitve resist is the bead at the edge of the wafer after spin will not come off in the developer as it does (pretty much) with negative resist. There are, of course, work arounds so it is hardly ever a deal breaker. Roger Brennan Solecon Labs Reno, NV 89521-5926 roger@Solecon.com -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org]On Behalf Of Paul Nguyen Sent: Tuesday, October 27, 2009 8:24 AM To: MEMS-talk@memsnet.org Subject: [mems-talk] Positive vs. Negative Resists in MEMS processing Dear all: I would like to hear your experiences of using Positive vs. Negative resists in MEMS processing. What are the PRO vs. CON? I appreciate your information. Thanks and regards, Paul