Steve, Let me do a free test for you. This is possibly a similar situation to aluminum etching on Silicon wafers. What we discovered was the aluminum layer needed 20 minutes of HMDS vacuum prime instead of 5 minutes. This is due to the lower level of Hydroxyl ions on aluminum. It is highly probable that Titanium needs longer and better adhesion promotion than Aluminum. Bill Moffat, CEO Yield Engineering Systems, Inc. 203-A Lawrence Drive, Livermore, CA 94551-5152 (925) 373-8353 www.yieldengineering.com -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Stoffels Steve Sent: Wednesday, February 06, 2008 4:56 AM To: mems-talk@memsnet.org Subject: [mems-talk] Ti-etching with SPR-220/7 resist Hey everybody. Does anyone have experience etching titanium with SPR-220/7 resist as a mask for patterning? I am using a H20:BHF (9:1) solution to etch titanium, however etching a 100nm thick titanium layer gives a undercut of 1.3 micron under the resist. Did anyone else experience this problem or have a solution for this? I tried a postbake in a oven of the resist on three different samples 80C 15mins / 80C 25mins / 90C 15mins, this did however not change the outcome. I also tried to etch in a H2O2 solution, this however takes 2.5 hours to etch and after this time the resist started to delaminate. Any help would be greatly appreciated. Greetings, Steve Stoffels.