Martin,
Thanks for the tip, but won't aqua regia without the water dilution attack the
AZ5214E photoresist or the underlying uncrosslinked SU-8?

Mr. Jeffrey Mun Pun YUE
Division of Bioengineering
E3A-07-02, Nanobioanalytics Lab
7 Engineering Drive 1
National University of Singapore
Singapore 117574
Tel: (65) 65166482, Fax: (65) 68723069
E-mail:  [email protected]

-----Original Message-----
From: [email protected] [mailto:[email protected]] On
Behalf Of Michael D Martin
Sent: Wednesday, March 07, 2007 10:21 PM
To: [email protected]
Subject: [mems-talk] Re: Does H2O2 attack AZ5214E? Does HCL:HNO3
attackuncrosslinked SU-8

Jeffrey,
   Strong bases are frequently rough on any polymer. I would just use HF to etch
the Ti (though there are lots of ways to etch it), assuming your process will
take it.  Aqua Regia can be a little tricky as it is sometimes hard on resists
and "ages" rapidly.  We use 3:1 HCl:HNO3 at room temperature without the added
water but use it immediately after mixing.  After about 10min the solution
properties change and you should discard the solution.