Dear Ramesh,

depending on the sacrificial layer etch that you use, the bending and
sticking of the cantilever is a surface-tension-related effect when
drying the liquid washing solution (e.g., deionized water) after
etching. Possible solutions are:

- Design: include small protrusions into the cantilever to reduce the
contact area between cantilever and underlying substrate

- Process: Try a dry-phase or vapor-phase etching process, e.g.
isotropic silicon etching in XeF2 (though I am not sure about the
selectivity towards Al). Here at ETH, we use an HF vapor etcher from
AMMT GmbH (www.ammt.com) in Germany to remove sacrificial silicon
dioxide layers in a stiction-free way. An alternative solution is
super-critical drying, though the required setup is quite complex .

Best regards,

Jan Lichtenberg

> I have fabricated array of mico cantilevers using aluminum. dimension are
> length=300um, width=200um, height=2um.(air gap3-4um) i am using sacrificial
> material and washing it away to free the cantilever. But most of the
> cantilevers have collapsed. I have also calculated the bending due to its
> own weight and i am getting answer in nanometers. Is this happening because
> of the E(Al)=70GPa or dimension is too large and collapsing due to its
> ownweight? Or am i making calculation mistake?
> I would really appreciate if you guys could answer my question.
> Thanks
> Ramesh