3 troubleshooting transducers/sensors – INFICON XTC/C Thin Film Deposition Controller User Manual
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XTC/C - XTC/2 Operating Manual
6.3.3 Troubleshooting Transducers/Sensors
NOTE: The most useful tool for diagnosing sensor head problems is the DVM
(Digital Volt Meter). Disconnect the short oscillator cable from the
feedthrough and measure the resistance from the center pin to ground.
If the reading is less than 1-2 megaohms, the source of the leakage
should be found and corrected. Likewise, with the vacuum system open
check for center conductor continuity, a reading of more than 1 ohm
from the feedthrough to the transducer contact indicates a problem.
Cleaning contacts or replacing the in-vacuum cable may be required.
A somewhat more thorough diagnosis may be performed with the
optional Crystal Sensor Emulator, 760-601-G1. See
for a discussion of its use and diagnostic capabilities.
NOTE: A more detailed troubleshooting guide is shipped with the sensor. Refer
to that manual for more detailed information in some cases.
Table 6-2 Troubleshooting Transducers/Sensors
SYMPTOM
CAUSE
REMEDY
1. large jumps of thickness
reading during deposition
a. mode hopping due to
defective crystal
a. replace crystal. use
ModeLock measurement
system
b. stress causes film to peel
from crystal surface
b. replace crystal or try silver
coated crystal; consult factory
c. particulate or "spatter" from
molten source striking crystal
c. thermally condition the
source thoroughly before
deposition, use a shutter to
protect the crystal during
source conditioning
d. scratches or foreign
particles on the crystal holder
seating surface (improper
crystal seating)
d. clean and polish the crystal
seating surface on the crystal
holder
e. small pieces of material fell
on crystal (for crystal facing
up sputtering situation)
e. check the crystal surface
and blow it off with clean air
f. small pieces of magnetic
material being attracted by the
sensor magnet and contacting
the crystal (sputtering sensor
head)
f. check the sensor cover’s
aperture and remove any
foreign material that may be
restricting full crystal
coverage