Try a dry process to release your fragile structures. You could use oxigen
plasma to remove the photoresist or a SOI-wafer technology and remove the buried
oxide with vapour HF. We did cantilevers on SOI substrate 300 nm thick and used
the vapour HF tool from Idonus (www.idonus.com) to release them with a yield
close to 100%.

Best regards,

Michael

-----Original Message-----
From: Tolga Kaya
Subject: [mems-talk] Releasing cantilever beams

Hi, I am trying to release my double clamped cantilever beams after KOH etch. I
etch my SOI wafer from bottom with KOH, then attach it onto a support wafer
using S1813 and do RIE from top. I put device with its supprt wafer in Acetone
for 1-2hours in order to make sure device is fully detached from the support
wafer. However, when I try to take the sample from acetone, beams are broken.