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.