Hi Jobert,

   There is an article called "A modified Bosch-type process for precise
suface micromachining of polysilicon" published in April 2002 in the Journal
of MicroMechanics and MicroEngineering which claims to produce etch depths
you want with relatively no scalloping.  However, I have not tried this
particular process myself.  The link to the paper is listed below.

http://ej.iop.org/links/q34/2FsVADuPqRO+N6kAjEMr9w/jm2320.pdf

Phil Tabada


>From: Jobert van Eisden 
>Reply-To: General MEMS discussion 
>To: "'[email protected]'" 
>Subject: [mems-talk] Anisotropic c-Si RIE
>Date: Mon, 27 Oct 2003 19:05:20 -0500
>
>Dear all,
>
>We are trying to etch vias (3-10 um) to a depth of 5 um with sidewall
>roughness under 30 nm. The mask we use is 1 um thermal oxide. I would
>like to ask you all if there is any way the Bosch process can be
>adapted, or if there is a gas chemistry we can use to do a RIE process
>that gives us these smooth sidewalls. There should be little or no mask
>undercut.
>
>We have tried running a Bosch like recipe using very little ICP power
>and short cycles, which gave us too much sidewall roughness.
>The available chemistries are CHF3, CF4, O2 and N2 on the dieletrics
>chamber and SF6, C4F8, O2 and Ar on the Bosch chamber.
>
>I would very much appreciate ideas and suggestions.
>
>Regards,
>
>Jobert van Eisden
>Graduate student
>SUNY Albany
>
>_______________________________________________
>[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.memsnet.org/

_________________________________________________________________
Cheer a special someone with a fun Halloween eCard from American Greetings!
Go to  http://www.msn.americangreetings.com/index_msn.pd?source=msne134