>>> 'ptherm' problem from evan -- Fri Jan 26 16:27:17 1990 <<<

enabled in order to borrow pressure gauge.

>>> 'ptherm' problem from tom -- Wed Feb 21 11:00:17 1990 <<<

Joe Carls would like me to do some processing in the ptherm but with
H2. I would like to have some H2 hooked up in the next week or so
if possible. Thanx.

>>> 'ptherm' problem from tom -- Thu Feb 22 09:52:57 1990 <<<

Leaks at about 50 mTorr/min. Not good.

>>> 'ptherm' problem from rnorman -- Thu Feb 22 14:54:06 1990 <<<

I looked at the ptherm and isolated the leak to below the gas valve; meaning
it is located in the MFC area.  All the gas lines should be pumped out one
at a time to locate which channel the gas is leaking from; the leak could
also be in a fitting or the N2 vent.  I will continue tomorrow.

>>> 'ptherm' problem from rnorman -- Fri Feb 23 09:46:09 1990 <<<

The ptherm was leak checked with the hld and no leak was found.  I blanked
off each gas line one at a time, even the vent, and not noticeable change
was seen.  I also pumped out every gas line and capped off the vent and
no change was noticed.  It looks like we could be corrosion or heavy build
up inside the "gas mixing tube".  At this point I am up for suggestions.

>>> 'ptherm' problem from rnorman -- Fri Feb 23 10:05:28 1990 <<<

Problem: High ROR in the chamber.

Solution: No leak was found and it seems to be outgassing of
         the "gas mixing tube".  See previous problem for
         details.  I also noticed that the longer the chamber
         and gas mixing tube was pumped on the ROR decreased.
         The ptherm is operational.

>>> 'ptherm' problem from xwu -- Sun Feb 25 12:57:50 1990 <<<

ptherm line 1 doesn't go through the flow meter, the pressure is always
about 170 mTorr, and the purge gas has very low pressure, about 15 mTorr,
could someone come to check if these two lines have some thing wrong 
there?

I don't think ptherm is usable now.

Xin
(xwu@argon)

>>> 'ptherm' problem from rnorman -- Mon Feb 26 07:28:11 1990 <<<

Problem: Line 1 no flow and the purge gas is flow is very low.

Cause: The line 1 MFC connector was loose, and the purge gas
       needle valve was not set open enough for more flow.

Solution: The line 1 MFC connector was push on tightly and
          the purge needle valve was opened more.  The
          randex is up.

>>> 'ptherm' problem from rnorman -- Tue Feb 27 14:00:45 1990 <<<

The ptherm still has a high ROR.

>>> 'ptherm' problem from rnorman -- Tue Feb 27 14:51:58 1990 <<<

After closely looking at the ptherm I found some small leaks at
all 4 gas channels, some more then others. I begin
repairing/replaceing the valve controllers on each channel tomorrow.
The ptherm is down.

>>> 'ptherm' problem from rnorman -- Wed Feb 28 14:41:48 1990 <<<

I have rebuild all valve controllers and cleaned the gas mixing tube
of corrosion.  Tomorrow I will continue to reassemble the MFC's and
test the ROR.  The ptherm is still down.

>>> 'ptherm' problem from rnorman -- Thu Mar  1 08:25:55 1990 <<<

Problem: The ROR was in excess of 50 mt/min. with in the gas mixing
         tube; the chamber, with the gas valve shut-off, ROR was less
         then 4 mt/min.

Cause: Each of the 4 gas channels were leaking, some more then others.
       The gas mixing tube was also corroded with iodine when it was 
       used in Hydrogen Iodine. (The iodine affected the Stainless
       tube and caused heavy rust inside the tube.)

Solution: The main three gas control valves, Channel 1,2 &3, were removed
        cleaned and rebuilt (replacing o-rings and bad seats where applicable.)
        Channel 4, HI, was blanked off entil thorough cleaning.
        The gas mixing tube was also removed and cleaned with HF and
        Nitric to remove the internal rust, the tube was then
        passivated in Nitric; after which it was rinsed in DI and then
        in methanol.  Each line was tested for ROR and did not exceed
        4mt/min; with the chamber ROR being 1mt/min.  The ptherm
        is now up for use.

>>> 'ptherm' problem from liang -- Thu Mar  1 17:35:19 1990 <<<

There is a problem with flow volve #1. It dose not open at all.
Another problem is that I use same flow rate (1.5 reading on 
display) as I used before, but the pressure in the chamber is
much higher than before with veiner fully opened (5mTorr 
compared to 200mTorr now ). I don't think the pump rate has been
changed recently and it must be some problem with volve calibration.
The third problem I noticed is that it seems the vernier volve 
does not oper properly. When I open the venier, the chamber
pressure does not go down. Please look into it.

>>> 'ptherm' problem from rnorman -- Fri Mar  2 09:39:15 1990 <<<

Problem: Channel 1 does not open, also the throttle valve is
         not working properly.

Cause: The channel 1 MFC case was broken, this caused the connector
       to the MFC to unplug.  The throttle valve was sticking.

Solution: The case to MFC 1 was replaced, also all the fittings on that
          line were tighted; I did find a couple loose VCR fittings.
          A ROR test was then done and was 5mt/min.  The throttle
          valve pneumatic cylinder was lubricated and the air exaust
          valves were adjusted to increase movement of the throttle
          valve.  The ptherm was tested and up for use.

>>> 'ptherm' problem from rnorman -- Thu Mar 15 07:39:07 1990 <<<

Later this morning I will be removing channel 2 MFM and control
solenoid to install a Unit MFC.  I found that the channel 2 MFM
is calibrated for 200 sccm and its solenoid is calibrated for 
2000 sccm.  This mismatch can cause flow control problems.

Let me know if the ptherm being down for most of today will
cause problem for anyone.

>>> 'ptherm' problem from rnorman -- Thu Mar 15 14:43:41 1990 <<<

ptherm channel 2 has been disconnected for modifications.  A new
Unit MFC will be installed after re-wiring the 0-20 volt solenoid
into pot, which will inturn go to the MFC.  Channel 1 and 3 are
operational if you wish to use it tonight.  The ptherm will
be down in the morning to continue the work.

>>> 'ptherm' problem from rnorman -- Fri Mar 16 08:43:05 1990 <<<

Problem: Channel 2 was not regulating the H2 well, not at all.

Cause: Looking at the flow control hook-up it was found that the
       Tylan MFM was calibrated for 0-200 sccm and the flow control
       solenoid was calibrated for 0-2000 sccm; which may have contributed
       to the problem.  Tylan MFM and MFC admittedly do not control
       H2 or He well.

Solution: The old tylan MFM and the Brooks Flow Control Solenoid were
          removed and a new Unit MFC was install, which is calibrated
          to 0-200 sccm of N2.  A potentiometer was install to drop the
          0-20Vdc set-point voltage to 0-5Vdc for the Unit MFC.  Another
          gas regulator was also installed on the H2 bottle that is 
          30" to -30" Hg.  The voltage on the pot was set to 5.00Vdc
          and was tested.  The H2 bottle is close and the gas line is
          pumped out to the Unit MFC.  The ptherm is up.

>>> 'ptherm' problem from parrish -- Tue Mar 27 10:26:00 1990 <<<

system down for maintainance on the roughing-pump, and the roots blower
should be back up by noon.

>>> 'ptherm' problem from parrish -- Tue Mar 27 14:07:04 1990 <<<

no problem to report, the oil in the blower and the roughing-pump has
been changed.

>>> 'ptherm' problem from liang -- Fri Apr 13 18:08:54 1990 <<<


the gas flow through mass flow regulator #1 stops during 
plasma etching. It seems the regulator does not work properly.
chunlin

>>> 'ptherm' fix from rnorman -- Wed Apr 18 13:09:02 1990 <<<

Problem: Gas flow on MFC #1 stops during etching.

Solution: After about 15 minutes of running a plasma to problem
        occurred with channel 1 or any other MFC.  The ptherm is up.

>>> 'ptherm' problem from gtdu -- Tue May  8 15:59:18 1990 <<<

At the beginning , the channel 1 did't work , no CF4 gas flow passed through,
30 minutrs late , the gas channel  opened automatically , but the flow was
unstable.

guotong du

>>> 'ptherm' fix from rnorman -- Wed May  9 07:42:45 1990 <<<

Problem: Channel 1 not working and when it was the flow was unstable.

Solution: I could not duplicate the problem. Ptherm is up.

>>> 'ptherm' problem from xwu -- Mon May 14 14:57:28 1990 <<<


the channel 1 of gas flow control panel seems has some problem:

the status light keep red when gas in stable flow;

the flow adjestment is quite different than it was before (was when 0.50
the gas flew reads 50, but now needs 1.30 for the same flow reading), and
the flow is unstable, it gradually slowly drop.

I think the circuit inside might need to be checked.

the ptherm is still up.

Xin

>>> 'ptherm' fix from rnorman -- Tue May 15 11:31:29 1990 <<<

Problem: Problem with channel 1 flow.

Cause: Other then finding the calibrate knob off I could not find a problem;
       the "cal" knob was set at 1.42, should be set at 0.42 for CF4.

Solution: I could not duplicate the problem, it ran good for me.  This 
          could be an intermittent problem or just operator error.
          The ptherm is up.
