Dear M. Aslam,

you may use a multi-layer SIO2 - SI3N4 as mask. SI3N4 needs a thins SIO2
layer to prevent pinholes during etching, but it shows virtually no etch in
TMAH (I experienced this with KOH, but I read it stands also TMAH).

best regards,
         Stephane Durand


At 07:02 05/03/02 -0800, vous avez icrit:
>i have got silicon <100> wafers with EPI layer of Ar.
>I want to etch through the silicon wafer to make some
>windows but EPI works as etch stop(i think).  How can
>I etch EPI layer with wet etchant like TMAH.  If i
>keep on etching the wafer, EPI layer etches very
>slowly but my mask ( SiO2 ) etches rapidly as compared
>to EPI layer.  Is there any body to help, Please.
>
>Thanks
>
>M. Aslam
>Try FREE Yahoo! Mail - the world's greatest free email!
>http://mail.yahoo.com/
>_______________________________________________
>[email protected] 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.mems-exchange.org/

---------------
Stiphane DURAND
---------------
Laboratoire d'Acoustique de l'Universiti du Maine
LAUM - UMR-CNRS 6613
avenue Olivier Messiaen
F-72085 Le Mans Cedex 9
---------------
Serveur du LAUM : http://laum.univ-lemans.fr
---------------
Ecole Nationale Supirieure d'Inginieurs du Mans (E.N.S.I.M)
rue Aristote
F-72085 Le Mans Cedex 9
---------------
Serveur de l'ENSIM : http://ensim.univ-lemans.fr
---------------
     Email : [email protected]
     Tel.  : 33.(0)2.43.83.39.54 (bureau/office)
     Tel.  : 33.(0)2.43.83.35.93 (secretariat E.N.S.I.M.)
     Fax.  : 33.(0)2.43.83.37.94 (E.N.S.I.M.)
     Tel.  : 33.(0)2.43.83.32.70 (secretariat L.A.U.M.)
     Fax.  : 33.(0)2.43.83.35.20 (L.A.U.M.)
---------------
Serveur de l'Universiti :http://www.univ-lemans.fr