INFICON UHV Bakeable Sensor - Manual (Page 47)

5 - 3
PN
07
4-
15
4N
UHV Bakeable Sensor Operating Manual
Thermal instability: large
changes in thickness reading
during source warm-up (usually
causes thickness reading to
decrease) and after the
termination of deposition
(usually causes thickness
reading to increase). Excessive heat applied to the
crystal. If heat is due to radiation from
the evaporation source, move
sensor farther away from source
and use Low Thermal Shock
crystals (PN SPC-1157-G10) for
better thermal stability.
If the source of crystal heating is
due to a secondary electron
beam, use a sputtering sensor.
No cooling water.
Water flow rate is low.
Water temperature too high. Check cooling water flow rate.
Heat induced from electron flux. Use sputtering head for
non-magnetron sputtering.
Poor thickness reproducibility. Erratic source emission
characteristics. Move sensor to a different
location.
Check the evaporation source
for proper operating conditions.
Ensure relatively constant pool
height and avoid tunneling into
the melt.
Use multiple sensor option if
available on controller.
Material does not adhere to the
crystal. Check the cleanliness of the
crystal.
Use gold or silver or alloy
crystals, as appropriate.
Evaporate an intermediate layer
of proper material on the crystal
to improve adhesion.
Table 5-1 Symptom, Cause, Remedy (continued)
SYMPTOM CAUSE REMEDY