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System Manual
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WARNING
BEFORE PROCEEDING WITH ANY MAINTENANCE WORK, READ SECTION 1 - HEALTH AND SAFETY
.
Unable to strike a
Plasma
1)
Chamber pressure out of correct operating range. Set correct pressure.
2) Other process variables incorrect. RF will not be turned on until electrode
temperature, gas flows and process pressure are close to demand values.
3) Gas isolation valves not operating. Check for correct compressed air supply.
4) RF generator not operating. Check that generator’s mains switch is set to
ON, and that the AC ON indicator is lit. Check CB4 is made.
NOTE:
RF generator will only switch on when the chamber is below
600 mbar (vacuum switch closed).
Is RF generator MAX POWER indicator on or the reflected power high? If so,
refer to the RF generator and automatch unit manuals..
5)
Automatch unit problems: read the following text:
Automatch set to 'manual' with capacitors in the wrong positions (retune
manually or set to 'auto').
Automatch not powered (connect automatch cables)
Automatch capacitor(s) stopped at maximum or minimum (some versions
of automatch require manual retuning if a capacitor reaches an end stop -
retune manually away from the end and set to 'auto')
A good match and a plasma can be obtained by manual tuning, but not by
automatching:
a)
The capacitor electrical end stop positions do not coincide with the
mechanical maximum and minimum points of a variable capacitor
(usually means the capacitor has slipped mechanically on the drive
shaft; re-align the electrical and mechanical end positions and
retighten the shaft connections)
b)
Refer to instructions for setting up the automatch - it is normally
necessary to manually tune to a good match, then adjust the auto
mode to recognise this as a good match point. In some systems re-
teaching is required for process conditions which are very different
from each other.
Arcing between the vanes of an air-vane variable capacitor. (Turn off the RF
immediately - the capacitor can be permanently damaged. Investigate for
vanes which are out of alignment. Repair may be possible, but arcing
usually requires the capacitor to be replaced.)
6) Is RF generator OVERHEAT indicator on? If so, refer to the RF generator
manual. Water-cooled versions: turn on the water, check for blocked pipe
or high back pressure. Air-cooled versions: check for obstructions to air
flow and high ambient temperature.
Troubleshooting
Printed: 25-Oct-07, 11:47
Page 7-5 of 12
Issue 1: August 07
Summary of Contents for OpAL
Page 14: ......