Hi Bagel Kuo,

I have been working extensively with SU8 and I have tried to used it
as an etch mask for KOH. Don't bother It does NOT work!! SU8 resist KOH but
it will come off from your silicon wafer.

It's true that there are some adhesion promoters in the market as it has
been mentioned earlier (Su8 relase and adhesion layer form Microchem), but
they don't work for KOH. SU8 is a good etch mask when using dry etch
(RIE or DRIE). I have been etching 800um using a SU8 mask.

Good Luck
Gabriela
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Gabriela Juarez Martinez
Dept. Electronics. Rankine Building
Glagow University. Glasgow G12 8LT UK.