Protek by itself doesn't survive well in KOH.  However I've had good results
using Protek to bond a dummy wafer to the surface I wanted to protected.  With
15% KOH 1um oxide on the dummy wafer will survive thru-wafer etch if you drop
the temperature to 60 degC.

Roger Shile

-----Original Message-----
From: mems-talk-bounces+rshile=nanoink.net@memsnet.org [mailto:mems-talk-
bounces+rshile=nanoink.net@memsnet.org] On Behalf Of Alessandro Distefano
Sent: Thursday, November 17, 2011 11:15 AM
To: mems-talk@memsnet.org
Subject: [mems-talk] PZT in KOH

Hi all,

I need your help.

Someone know how to protect a PZT layer deposited by sol-gel (about 400nm) on
a Ti-Pt electrode substrate of Si in KOH etching (15% solution, 85 ° C),
avoiding under-attack ?

I tried some solution but with poor results:

1. photoresist about 10um -> failed
2. ProTEK on PZT -> failed
3. mechanical clamping on a sample holder -> failed I need to work with
fragile membranes

Anyone has some advice?

Thank you
Alessandro