Hi Leo,

No problems so far, as long as you keep the released parts on the down
side to have the help of gravity (only matters because I have _very_
floppy cantilevers). I had an issue once, when the relative vapour
pressure of water in the cleanroom was too high, where drops/beads of
liquid formed on my wafer. After that, it hasn't happened, though. One
thing to consider might be to have a radiative heat source, like a light
bulb shining on the back side of the wafer to make sure it is always
warmer than the HF vapour mixture below it. Just to make condensation
less likely - but as I said this has not been a real problem. According
to the reference I found, it should help avoid stiction to dry the wafer
at 120 degrees C afterwards. I haven't tried, so can't comment on it.
Additionally he claims that you should heat the HF solution to 40
degrees C, but I didn't do that, as I expect that will definitely
increase drop condensation on the wafer...

// Morten

Xiaoguang Liu wrote:
> Hi Morten
>
> Thanks for sharing your process. I'm wondering if your setup causes
> problems with stiction? I mean moisture induced stiction for the
> released MEMS parts. Thanks
>
> Best
> Leo
>