Hallo Mohsen,

I tried to etch Nickel using Al etchant (H3PO4, HNO3, water), it was around
20min (without agitation) for 100nm Ni. I didn´t have the sandwich-structure, it
was just Ni-layer on polymer.
At that time if I stired the solvent or left the sample more than 20min the
undercuts are shown.

best regards,
Onny Setyawati

> Date: Tue, 3 Mar 2009 21:41:35 -0800
> From: kazemy1360@yahoo.com
> To: mems-talk@memsnet.org
> Subject: [mems-talk] Nickel etching
>
> Dear users
>
> I am a university student and my thesis relates to microcircuit (Hybrid thin
film) fabrication.  I use Alumina/Nichrome/Nickel/Gold sandwich structure and I
wanna make traces with 1 mil (25 micron) width.I use FeCl3 solution for nickel
etching and unfortunately I faced heavy undercut during nickel etching. Could
anyone please instruct me?