Hi,

I just posted on this yesterday, although I might have chosen a better
subject for the mail. Below is the relevant information as well as a
reference.

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It's quite a bit slower (etch rates reported around 200nm / min) but it
has the potentially huge advantage of not immersing structures in
liquids, which could be very important for fragile cantilevers and
objects with sticking issues. Basically just put your wafer upside down
on top of a PTFE/Teflon cylinder of proper diameter in a beaker with
just the bottom 1-2 cm filled with 40% HF solution - some people prefer
to heat the HF to 40 degrees centigrade, but I do fine just using room
temperature (of course, HF vapors are nasty, so remember to do this in a
fumehood with 4H gloves etc...). Afterwards you can heat the whole thing
to 120 degrees centigrade to further reduce the probability of sticking.

See:
Phuc Hong Pham: J. Micromech. Microeng. 17 (2007) 2125–2131

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Good luck with it :-)

// Morten

Barbara Cortese wrote:
> Hi all
>
> I'm interested in HF vapour etching. Could someone suggest a good recipe or
some references?
> I'm also looking for HF/methanol mixture vapour etching.
>
> Thanks
> Barbara