[mems-talk] Ti-etching with SPR-220/7 resist

[Stoffels Steve]

Hey everybody.

Does anyone have experience etching titanium with SPR-220/7 resist as a
mask for patterning?  I am using a H20:BHF (9:1) solution to etch
titanium, however etching a 100nm thick titanium layer gives a undercut
of 1.3 micron under the resist.  Did anyone else experience this problem
or have a solution for this?  I tried a postbake in a oven of the resist
on three different samples 80C 15mins / 80C 25mins / 90C 15mins, this
did however not change the outcome.
I also tried to etch in a H2O2 solution, this however takes 2.5 hours to
etch and after this time the resist started to delaminate.

Any help would be greatly appreciated.
Greetings,
Steve Stoffels.