Hello,
regarding the "overheating problem". Can you interupt and restart your
process, or is it a must to have your process run continously for the 10
minutes?
If you can interupt it, let your process run for, say 1 minute or half a
minute, then pause for, say 5 minutes to allow your sample to cool down,
then restart your process for 1 minute, then pause, and so on.
The idea is that during 1  minute of process time, the sample does not heat
up too much to cause carbonization of the PR. Of course, the "process-on
time" of 1 minute was just a guess, you need to find out by experiment.
There's temperature sensitive self adhesive decals available which
irreversibly change their colour above the rated temperature. You could use
them to monitor the maximum sample temperature during etching. If after 10
mins of process, the temperature was above, say 140°C, but after 1 minute
was still below 100°C, and your results are better with the process on/off
timing, then the sample temperature rise was the reason for your problems.
Then, a machine upgrade to water cooling might be justified.

Hope that helps.
Regards
Burkhard

-----Ursprüngliche Nachricht-----
Von: Isaac Wing Tak Chan 
An: [email protected] 
Cc: [email protected] 
Datum: Donnerstag, 20. Februar 2003 13:57
Betreff: Re: [mems-talk] Cl- and Br-contained plasma - toxic?


>Hi Martin,
>
>etching to prevent overheat the photoresist and carbonize it. My process
>requires long etch time, more than 10 mins. It's not too much of a problem
>to upgrade the RIE machine for that, if that is the way to solve the
>problem. But to upgrade to "try", then it may not be justified. Do you
>have any suggestions for me? Thanks a lot!
>
>
>Regards,
>
>Isaac Chan
>Ph.D. candidate in a-SiDIC research group
>Electrical and Computer Engineering
>University of Waterloo
>200 University Ave. W
>Waterloo, Ontario, Canada
>N2L 3G1
>(529) 888-4567 ext.6014
>
>