Good morning. At our side we use Paryleen as protective coating on top of the structured front side. Also Silicet has an holder for protecting the frontside during KOH etch. best regards, Peter Kuijpers MiPlaza Technology Laboratories Philips Research Europe High Tech Campus 04 Postbox HTC-4-1 5656 AE Eindhoven The Netherlands Tel.: +31 402743667 +31 612507027 Email: p.e.m.kuijpers@philips.com -----Original Message----- From: mems-talk-bounces+p.e.m.kuijpers=philips.com@memsnet.org [mailto:mems- talk-bounces+p.e.m.kuijpers=philips.com@memsnet.org] On Behalf Of Bhargav Nabar Sent: Thursday 30 September 2010 18:22 To: mems-talk@memsnet.org Subject: [mems-talk] AMMT KOH etch wafer holder Hi all, I would like to protect the front side of my silicon wafer in a KOH wet etch process. (30% conc 85 C). I have an aluminum oxide thin film on the front side that needs to be protected from KOH. I also have Lpcvd silicon nitride as the etch stop from the backside (I am trying to make suspended silicon nitride membranes and the aluminum oxide thin film is supposed to be on the top of the membrane) . I have tried using brewer science's Pro-Tek B3 but am facing adhesion issues. I am contemplating using a mechanical clamp .Does anyone have any experience with such clamps for eg, the AMMT clamp? Also any alternative methods or suggestions about alternative clamp manufacturers would be greatly appreciated. Thank you Bhargav Nabar UT Arlington Nanofab.