Dear All,

I am having a lot of problems using S1813 photoresist for my lift-off. It was
recommended to me in the past to use S1813 with LOR3A or LOR5A to help me
solve my lift-off problem. unfortunately, by using the bi-layer photoresist
system my lift off problem was solved but the developer, the AZ400K developer,
i used to do the lift off was etching my Al metal. Therefore, i was given
another recommendation to go back and use the S1813 only, but this time i had
to soak it in MIF-319 developer for some time before exposure to generate a
top layer with a lowered dissolution rate compared to the bulk of the
photoresist. Due to the lower dissolution rate in the top layer, a T-shaped
profile with overhanging lips supposedly should have been created, but when i
did SEM on the sample, i did not see the T-shaped profile?? My soaking time
was between 60s-90s.

Did anyone of you use this method? if so, can you please tell me what am I
doing wrong? or what should i do to solve this problem?  any other suggestions
is appreciated??

Hope to hear from you soon.

Ali