Poll on Use of PQuest at 200C

Jim McVittie mcvittie at snf.stanford.edu
Wed Nov 5 13:07:10 PST 2003


When the PQuest was first installed, the wafer chuck was heated above 100C a
number of times
to do silicon nitride depositions with no problems caused by the temperature.
The main problem
from the deposition runs was by-products on the chamber walls.  I am sorry
that I do not have
the details on the specific temperatures used. A while back, I loaned my
PQuest process file out
and never got it back. The PQuest report that I have for nitride dep says that
the deposition
temperatures ranges are from 100 to 300C. In addition, I recall that the
system was used at least
once for a high temperature H2 plasma anneal. I will contact the former
student, who did this
anneal, to see if he recalls what temperature was used. Let me point out a
couple facts about the
tool. At the time of its purchase, InP etching was the main reason why the
heated chuck specified.  Plasmaquest specified that InP etching needs at least
150C. The chuck temperature range in the PQuest specifications is -150C to
+350C. If the chuck was designed to go to 350C, I can not see why it should be
a problem to go to 200C.

While I understand why you are afraid to rock the boat and want to avoid
anything that might slow down your thesis work, I really hate to loss the
heated chuck capability of this
tool. We have no other etcher in the lab with this capability and we have InP
users who could
really use this capability.


Michael Wiemer wrote:

> I am nervous about these high temps.  It seems risky to make such a large
> change.
> We rely on the PQuest too and these high temps, even if they dont mess up
> other processes, may result in something being broken. Since the PQuest is
> not supported anymore by its parent company, when the PQuest goes down,
> there is always a risk that the problem is major and cant be fixed in a
> reasonable amount of time.  It seems like a bad machine to start altering.
> My 2 cents.  :)
> -Mike
> ----- Original Message -----
> From: "Jim McVittie" <mcvittie at snf.stanford.edu>
> To: <pquest at snf.stanford.edu>
> Sent: Monday, November 03, 2003 1:56 PM
> Subject: Poll on Use of PQuest at 200C
> > 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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