I used MAN 1410 a negative tone photoresist from Microresist http://www.microresist.de/ma-N1400_400_2005_en.htm The thickness of Al was 300 nm and I never observed deterioration of the metallic thin film. The developer was MA-D 533. The only weak point I heard about this PR is that is not easy to spin coat on glass wafers. Cheers, Schahrazede -----Original Message----- From: Wilson, Thomas Subject: RE: [mems-talk] Problems with lift-off using S1813 photoresist I will be trying next week for my lift-off work, the image reversal process for aluminum (and other metallizations) as described by Meier et al., "Fabrication of an all-refractory circuit using lift-off with image-reversal photoresist", IEEE Transactions on Magnetics, Vol 27, No. 2, March 1991. I will be using AZ 5214-E and AZ Developer. The latter is the only developer, so I'm told, that does NOT etch aluminum. I do know that AZ 351 did etch my aluminum films undesirably on previous processing steps, so I have to abandon that developer.