INFICON RSH-600 Rotary Sensor - Manual (Page 25)

3 - 3
IPN
1
5
3800
-G
RSH-600 Operating Manual
7. Crystal oscillates in
vacuum but stops oscillation
after open to air. a. Crystal was near the end
of its life; opening to air
causes film oxidation which
increases film stress. a. Replace crystal.
b. Excessive moisture
accumulates on the crystal. b. Turn off cooling water to
sensor prior to venting, flow
warm water through sensor
while chamber is open.
8. 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.) a. Inadequate cooling
water/cooling water
temperature too high. a. Check cooling water flow
rate, be certain that cooling
water temperature is less
than 30°C.
b. Excessive heat input to the
crystal. b. If heat is due to radiation
from the evaporation source,
move sensor further away
from source and use
sputtering crystals for better
thermal stability.
c. Crystal not seated properly
in holder. c. Clean or polish the crystal
seating surface on the crystal
holder.
9. Poor thickness
reproducibility. a. Variable source flux
distribution. a. Move sensor to a more
central location to reliably
sample evaporant, ensure
constant relative pool height
of melt, avoid tunneling into
the melt.
b. Sweep, dither, or position
where the electron beam
strikes the melt has been
changed since the last
deposition. b. Maintain consistent source
distribution by maintaining
consistent sweep
frequencies, sweep
amplitude and electron beam
position settings.
c. Material does not adhere
to the crystal. c. Make certain the crystal
surface is clean; avoid
touching crystal with fingers,
make use of an intermediate
adhesion layer.
Table 3-1 General Troubleshooting (continued)
SYMPTOM CAUSE REMEDY