Hi Andrea, The best etchants are commercial ones like CR-7 or CR-14, chrome etch 18, and similar. They have a long practical shelf life and are good investment. shay -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Andrea Mazzolari Sent: Sunday, September 02, 2007 11:04 PM To: General MEMS discussion Subject: [mems-talk] germanium etch Hi all, i need to make etch of germanium. As etchant i plan to use HNA solution. Here are the steps: 1) deposition of 100nm Cr mask 2) deposition of photoresist s1813 and patterning 3) etch Cr (???) 4) Germanium etch (HNA). could someone give me suggestions about a proper etchant which will etch Cr layer without attack s1813 ?