Hi Kishore. Are you etching the SiO2 as a release or sacrificial layer. In many cases when people are looking for selectivity to nitride they switch to silicon as a release layer. KOH will etch poly-Si without attacking your nitride or for a dry etch XeF2 shows a high selectivity to nitrides over Si (on order of 200:1 and higher). The other advantage of XeF2 is it is extremely selective to everything else so you can use a very thin oxide layer or photo resist to protect any Si you don't want etched. Could you switch to Si as a release layer? Regards David Springer XACTIX, Inc. 2403 Sidney, St. Suite 265 Pittsburgh, PA 15203 412 381 3195 davids@xactix.com www.xactix.com >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 >> Hi, >> I was wondering if someone could point me towards an etchant that would >> selectively etch SiO2, but not Nitride. I tried using BOE, but the >> selectivity was pretty low. >> Thanks, >> Kishore >> - -- >> __________________________________________________________________________ >> ____ >> Kishore Sundara-Rajan Dept. of Electrical Engineering >> Graduate Research Assistant University of Washington >> kishore@u.washington.edu Campus Stop 352500 >> Mobile : (206) 351-8101 Seattle WA 98105 >> Fax : (206) 632-3080 Office : (206) 221-6673 >> http://students.washington.edu/kishore www.kishore-sr.com >> PGP Finger Print: BE5A 90BE 904F 766B 979A 910E E831 C2C3 0347 235F >> __________________________________________________________________________ >> ____ >> -----BEGIN PGP SIGNATURE----- >> Version: GnuPG v1.2.1 (MingW32) >> iD8DBQFBbX7D6DHCwwNHI18RAguuAJ9uT6/AR6VxjTvbSSq0LmCIXpar+QCcCdcR >> pF+avp+fRDG7Y5MxDerTkb0= >> =Ko9W >> -----END PGP SIGNATURE----- >> _______________________________________________ >> MEMS-talk@memsnet.org mailing list: to unsubscribe or change your list >> options, visit http://mail.mems-exchange.org/mailman/listinfo/mems-talk >> Hosted by the MEMS Exchange, providers of MEMS processing services. >> Visit us at http://www.memsnet.org/