Hi Group,
I know it sounds like a trivial question, but I am recently
having great difficulty in removing AZ5214 photoresist that
has undergone image reversal.  Even after no further
processing beyond PR developing, I cannot easily strip the
resist in Acetone.  Boiling acetone seems to have little
effect on the resist. This is a standard procedure which I
have not until recently had any problems with.

See process below.  There is not prblem when I do the
positive-image process.  Should I try lower postbake temp or
lower flood exposure?  Why do you think I cannot remove the
resist in acetone??  Thanks!

Process is as follows:
Spin AZ5214E PR at 5000 RPM / 30 sec.
prebake at 110deg. C / 30 sec.
expose 8 sec. in KS - MJB-3 (I don't know the intensity
offhand)
Postbake at 125deg. C / 60 sec.
Flood expose 330 mJ/cm^2
Develop 45 - 50 sec. in AZ327 MIF.