I used to spray coat resist back at Motorola. I used to get 40,000 Angstroms to 60,000 Angstroms. It may be worth experimenting with simple small spray gun used fro spraying models. Bill Moffat ________________________________ From: mems-talk-bounces@memsnet.org on behalf of Oakes Garrett Sent: Fri 1/23/2009 10:23 AM To: mazzolari@fe.infn.it; General MEMS discussion Subject: Re: [mems-talk] Thick AZ-9260 Andrea, By default, AZ9260 is a resist designed for a 6.0 - 8.0 =B5m coating = thickness when spun between 3000 and 4000 rpm. One can increase the = thickness of a single pass coating by decreasing the casting rotational = velocity but this will come at the expense of thickness control. Film = thickness of 50 =B5m might require coating the resist four times or = more! The best solution is to look for a resist which is designed for the = needed thickness at 3000 rpm. You can look at the XT and nXT resists = from AZ-EM. They have materials designed for the thickness range you = desire and can be coated in only one or two passes. Best Regards, Garrett Oakes