Hi,
All your comments are highly appreciated!

To matthew,
i will try to contact the company, thanks!

To Morten,
 i need to choose a suitable process to achieve my design and i'm not sure
how to define the hole's dimension when we do wet etching or vapor etching
to release the structure. In my design, proof mass is about 1000 micron wide
and the beam is about 100 micron. your information is very useful. Also wet
etching is not nessary, i just want to figure out the relation between
hole's dimension and the undercut.

To 汪飞，
could you tell me the minimum size of holes which can let the echant in?
thank you :)
the releasing process depends on the concentration and the size of the hole
by wet etching. But if the hole size is too large, the natural frequency of
the device is hard to retain the expected value and maybe we need redesign
all the spring of the structure.


and is there any papers or thesis about perforation for realsing structure?

thanks !