Marco, I don't think they want us to recommend specific vendors in this forum, but if you'd like to call me, I can over the phone. I would recommend using one of the local mask vendors to make E-beam Chrome Masters for you. They can do a direct E-beam write on mask down to a 0.1 um spot (beam) size, possibly smaller (little unlikely), but almost no one in the MEMS industry needs or asks for sub-micron mask patterns. What is the application? Next level of even smaller geometries will/may require X-Ray lithography. You can probably get this book on loan from your University Library. http://www.springer.com/materials/book/978-0-306-43578-2 Good Luck, and Best Regards, Wendell McCulley www.InterMEMS.com 408 / 241-0007 (W) 408 / 482-8548 (C) -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Marc Reinig Sent: Monday, February 08, 2010 2:19 PM To: mems-talk@memsnet.org Subject: [mems-talk] patterning sub-micron holes in chromium I would like to place one to several sub-micron holes in a film of chromium on a glass slide. The chromium does not have to be very thick, only enough to block visible light, a few microns thick I think. Anyone have a recommendation on methods or any services that can provide this? Thanks in advance, Marco