Thanks a lot the input I've received. It looks like I have two choices.
1. Double spincoat with az4562 or 9260. Is there anything special in
the double coat process?
2. Ultrasonic development (I don't have magasonic transducer) using
su8. Recently I found my su8 doesn't stick very well onto wafer during
development. Features simply came off. This never happened to me
before. I was following the datasheet and not using HMDS or other
primer.
Thanks again for your input.