Dear Karin,

I do the same thing and found that the best we could do to keep the
temperature stable was to use an anodized aluminum wafer carrier.  It makes
better thermal contact than a carrier wafer and it seem to be as good as
laying the piece right on the chuck.  Without having a system with helium
backside cooling you will get some temperature changes.  The edges of your
piece will tend to get warmer causing faster etch rates than in the
center.  There are thermal conductive pastes, but we don't use them because
of the mess and contamination issues.

Good Luck!

Brent

Karin Buchholz wrote:

> Dear mems talkers,
>
> we have a RIE chamber with temperature control of the 3" carrier wafer.
> Since we are just using
>  waferpieces we just place these on top of the carrier wafer. It seems
> now that these small pieces
>  do not have proper thermal contact to the chuck, so the temperature of
> the sample is not constant
>  from etch to etch and the etch rate also varies by 50per cent...
>
> Do you have any suggestions how to provide good thermal contact? The
> manufacturer suggested
> Fomblin vaccuum oil, but it is impossible to remove it from the samples
> after etching...
>
> I appreciate any help! Have a nice day,
>
> Karin
>
> --
> Dipl.-Ing. Karin Buchholz
> Walter Schottky Institut
> Technische Universitaet Muenchen
>
> _______________________________________________
> 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/
begin:vcard
n:Garber;R. Brent
tel;fax:(860) 486-3756
tel;work:(860) 486-6679
x-mozilla-html:TRUE
org:University of Connecticut;Optoelectronic Science Center
version:2.1
email;internet:garber@engr.uconn.edu
title:Sr. Research Specialist
adr;quoted-printable:;;UCONN=0D=0A54 Ahern Lane=0D=0AU-5219;Storrs;CT.;06269;
fn:R. Brent Garber
end:vcard