Poll on Use of PQuest at 200C

Randall True true at snf.stanford.edu
Mon Nov 3 14:38:50 PST 2003


I do not think that a new high temperature H2 process should be approved
on the PQuest. As you know very well, we have had many problems with the
Pquest in the recent past, both with availibility and compatibility of
processes. The is why you adopted a policy of no new processes on the
system. Since you established that policy and decided to split the week
between GaAs and Non-GaAs, no further experiments have been done to
investigate what the root cause of the processing problems were. Moreover,
you never provided the compiled list of approved Non-GaAs processes as
promised. Given that procedures for introducing new Non-GaAs processes, or
even evaluating currently used ones, have not been put in place, I don't
think it is appropriate to approve this new high-temp H2 process. This
would be inconsistent with your policy changes in June.

I also have concerns about running the system at 200C. If something goes
wrong, the system could be down for a considerable amount of time. I think
another, non-high performance etcher, like drytek4 or MRC should be used
instead. I, my company, and many other users are counting on the PQuest
being operational and consistent, and we cannot afford for it to go down
yet again.


On Mon, 3 Nov 2003, Jim McVittie wrote:

> PQuest Users,
> I have 2 users, who would like to treat their samples in a H2 plasma at
> temperatures between 200 and 250C. The PQuest should be able to do this
> since it was designed to do PECVD as well as etching in that it has a
> heater in the wafer check. Right now we have no written procedures for
> going above 90C and there is a question about how high of a temperature
> the Vespel wafer lift pins can take. As for the Vespel pins, I am still
> checking to see which type of Vespel was used for making them. The
> mechanical properities for the lowest grade Vespel are good to 280C.
> If the all currents materials in the system will allow going to 200 or
> 250C, what is your opinion of allowing these users to use the PQuest in
> this mode?  Right now I do not believe their will be a problem but we
> have not used the chuck heater for a number of years.
>     Thanks, Jim

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