Poll on Use of PQuest at 200C

Jim McVittie mcvittie at snf.stanford.edu
Wed Nov 5 12:15:23 PST 2003


See reply below.

> Jim,
> I know essentially nothing about that H2 treatment, so it is hard to vote
> yes or no. But I have a few concerns. Firstly, can the rubber ring sustain
> such high temperature?

To go above 100C the chuck o-ring has to be removed. With this o-ring removed,
no rubber
/polymer parts should get hot when the chuck is heated above 100C. The
processes to worry about in regard to the o-ring are those using high
percentages oxygen, such used for chamber cleaning and etch polymers.

> Is there a cleaning/seasoning recipe required after/before the high-T H2
> procedure? And will it make a serious damage or contamination to the
> system if a wrong wafer is put in for that H2 procedure?

As with any significant process changes in a plasma system, the chamber needs
seasoning before starting a new process. This is true for all process changes.
If your processs is different than that used by the previous user, the general
rule is to start by seasoning the chamber using the new process and a few
dummy wafers.

> If the system is able to handle the procedure, are there special steps to
> take before and after the H2 plasma procedure, or, will the procedure be
> much trickier than the standard one, so that users might be more
> vulnerable to mistakes?

At this time, I do not see that a H2 process will cause any special problems
other than the expected thermal stress on the chuck and the connections to it.
There would be additional procedures needed before and after heating the chuck
above 100C. As mentioned above the chuck o-ring would have to removed and
replaced afterwards. In addition, we would probably want to blow out the chuck
cooling line with N2 before heating the chuck.


> Hui
> Quoting Jim McVittie <mcvittie at snf.stanford.edu>:
> > 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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