I recommend you try AZ5214E in image-reversal mode (relatively simple). See
application note AZ 5200-E-IR Negative Tone Processsing. I now can do 900-nm
thick  lift-off (30-min soak and 10-sec sonication) of 4-micron space, 6-micron
line Nb gratings routinely (for 900-nm as opposed to 500 nm however, I found I
need to increase the PR thickness via two successive spins (4000 rpm) and two
softbakes => 1.8-um thick resist). Good luck.

Thomas
________________________________________
From: [email protected] [mems-talk-
[email protected]] On Behalf Of Jie Zou
[[email protected]]
Sent: Thursday, May 20, 2010 12:55 AM
To: General MEMS discussion
Subject: Re: [mems-talk] liftoff with AZ5214

Agree with Mamun. Sputtered metal generates an apron on the edge. Try e-beam
or thermal evaporation.

Another suggestion is in step10, to soak your sample overnight before try
ultrasonication. If possible, avoid ultrasonication.

Jie