It is LPCVD silicon nitride. Thickness is 70nm. Under silicon nitide there are 20nm of LPCVD silicon dioxide. Silicon dioxide is etched by KOH, right ? And so the underlying silicon dioxide layer was removed. Maybe this is the cause i've lost cantilevers and bridges ? Best regards, Andrea ----- Original Message ----- From: "shay kaplan"To: ; "'General MEMS discussion'" Sent: Wednesday, December 06, 2006 6:05 PM Subject: RE: [mems-talk] silicon nitride bridges and cantilevers > If it is not LPCVD nitride they will be etched out by KOH. Even LPCVD > nitride will etch but slowly.