I found some etchmasks commonly used when etching parylene, but it is hard mask like Ti, Cu.. It isn’t proper to my experiment because applying etchmask’s solvent after RIE is too acidic to use my experiment.
So it would be excellent if there is some PR etch mask suitable for parylene RIE which is O2 plasma etching.
In my experience oxygen plasma etches most polymers with approximately the same speed. Therefore most photoresist materials will probably have more or less the same etch speed in oxygen plasma as parylene. However if your photoresist is thicker than your parylene this should be no problem.
We use aluminum as a hard mask for oxygen RIE of parylene, and it should also be posible to remove that with an alkaline solution, is that an option for you?
PDMS or Silicon-containing polymers (BARC, Si-ARC, etc.) have a good etching resistance in oxygen plasmas.
Polystyrene or polymers with aromatic cycle tend to be slightly more resistant to oxygen plasmas than the others (1.5 - 2 times more). Please also note that the etch rate of a polymer depends on the mass of the molecule: the lighter, the faster the etching. You could exploit this to reduce the necessary thickness of the mask.
I hope it will help you.
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