Hi Kevin,

it should be no problem. We use this recipe every day. What happens
sometimes is that you burn the resist (you see the non-developed regions
opaque) if you are too close to the evaporation source.
Of course you should use the AZ as reversal litho to obtain undercut. If you
do sputtering, lift-off is much more difficult.
Try also hot NMP (80°). I can lift more the 300nm of metal without
ultrasonication.

Good luck.
Daniel

* Dr. Daniel Grimm
* IFW Dresden
*            - Institute for Integrative Nanosciences -
* E-Mail:  [email protected]
* Phone: +49 351 4659-314
* Mobile: +49 177 4926561


-----Original Message-----
From: [email protected] [mailto:[email protected]]
On Behalf Of Kevin R. Anglin
Sent: Montag, 30. November 2009 23:51
To: [email protected]
Subject: [mems-talk] Problems with EOT Liftoff of 1.5 um diameter holes (Au
on GaAs)

I can't get good EOT liftoff for 1.5 um diameter hole arrays.

I'm using PR5214 spun 1.1 um thick, then deposit 50/1000 Angstroms
of Ti/Au. I use a supersonic acetone bath to liftoff, but it doesn't. I've
tried Chlorobenzene dips post-expose pre-develop, as well as varying baking
times and exposure times. Sometimes I liftoff donut shaped patterns instead
of holes.

Any suggestions would be welcomed, as I continually waste gold.