Aqua Regia will also etch Mo. You'll be left with a thin film of transparent MoO3. - Kevin Kevin Paul Nichols MESA+ Institute for Nanotechnology Mesoscale Chemical Systems Meander 151 University of Twente Postbus 217 7500 AE Enschede The Netherlands Office: +31 (0)53 489 26 31 Mobile: +31 (0)6 49 312 471 Fax : +31 (0)53 489 35 95 Email : k.p.nichols@utwente.nl Web : http://mcs.tnw.utwente.nl/ > From: Moshe> Reply-To: General MEMS discussion > Date: Tue, 22 Jul 2008 22:55:44 -0700 (PDT) > To: > Subject: Re: [mems-talk] Gold Etchant with selectivity over Mo > > I know that Aqua Regia may etch gold but I don't know what it influence on the > Mo. > Aqua regia composition : 25% concentration HNO3 + 75% concentration HCl > It is very corrosive solution, please be careful!