Dear Mems experts

I have two visiting students from Germany who are making ultrathin SiN force
microscope cantilevers, of order 350-800 Angstroms thick and up to 200 microns
long.

The last stage of the process is an anisotropic etch in KOH to free the
cantilevers from the underlying silicon, followed by critical point drying in
C02.

During the etch, the Si bubbles like crazy, to the extend that we are surprised
that the cantilevers even survive!

Survive they do, however we would like to suppress the bubbling if possible.
Can anyone offer any suggestions? We apologize if this is a well-know problem
with a well known solution.... it is only well known to those who know it well
(which is not us!)

Best wishes from a fan of MEMS ... John Sidles