In my experiments, I tried a post bake procedure for a 20 u thick AZ
P4620 photoresist spun on a glass slide. i observed that the features
were destroyed after the post bake. the post bake was done for 5 min
at 120 deg. C. According to the literature, post bake is an optional
step for thick photoresist layer and the features may distort due to
"Reflow" if the hard bake is done. Can someone tell me a clear  reason
for this distortion for thick photoresist.

--
RUPESH SAWANT
Biomedical Engineering,
The University of Akron, USA.
Tel: 330.338.8546