Hello all,

I was looking for the definition of "hard bake" to enhance
substrate-photoresist interface during wet etch processes. I found
that there is no exact definition for that.

Some of the users simply keep their developed PRs at elevated
temperatures and call this "hard bake" while some other users use
"UV-curing tools" to cure their PRs before keeping their PRs at
elevated temperatures for extended time, or some others use a
convection oven to hard bake their PRs.

 From here I understand that the definition is not very important as
long as the final result is successful... But from my experience, I
know that keeping the PR at elevated temperatures is simply called
"reflow" but not "hard bake".

My question is that:

What recipe should I use to enhance my silicon-PR interface for ~90
minutes of BOE (6:1) etch?

I am thinking about modifying my mask, but before starting that I want
to see what I can do with the example that I have in my hands. This
way it will be much cheaper, and if there is a solution, it will
definitely be much faster than modifying my masks and doing everything
from scratch...

I have several PR options, which are:

SPR220-3.0,
SPR700-1.2L,
SPR955-CM 0.9, or
SPR955-CM 2.0

Is there somebody who used one of those PRs, and achieved a good
adhesion against BOE(6:1) etch for extended etch time (~90 minutes).

Best regards,

Mehmet Yilmaz
Mechanical Engineer