There can be two problems; as i suspect. 1) Your oxide layer is not completly removed. so your Cr is not going in Cr etchant. 2) Or u might be using KI based gold etchant.which will not affect the Cr, but HNO3+HCl based gold etchant (Aqua regia) will etch Cr very fast.But be careful for underetching. How you are depositing top oxide layer? Best Luck -abhay Joshi Research Scholar, UIniversity of Pune India. > ---------- Forwarded message ---------- > From: "Andrea Mazzolari"> To: "General MEMS discussion" > Date: Sat, 6 Nov 2010 21:14:55 +0100 (CET) > Subject: Re: [mems-talk] Chrome and Oxide > > Is there a way to etch chrome oxide ? i tried gold etchant as > > recommended by a memsnet user, but that didn't work. > > What do you mean with "gold etchant" ? > I do not know which gold etchant you are using, i use a gold etchant from > sigma aldrich, i do not remember the chemical composition, but it has a > dark red color. Such gold etchant does not etch Cr at all... > > Best regards, > Andrea