INFICON Sputtering Sensor - Manual (Page 18)

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Sputtering Crystal Sensor Operating Manual
Crystal ceases to oscillate
during deposition before it
reaches its “normal” life Crystal is being hit by small
droplets of molten material
from the evaporation source. Use a shutter to shield the
sensor during initial period of
evaporation; move the
sensor further away.
Damaged crystal. Replace the crystal.
Built-up material on edge of
crystal holder is touching the
crystal. The crystal cover can not
have a build up of blown in
deposition material. This
material may create an
unreliable connection to the
crystal. Removal of the
deposition material is a
maintenance necessity.
Material on crystal holder is
partially masking the full
crystal area. Clean the crystal holder.
NOTE: Crystal life is highly dependent on process conditions of rate,
power radiated from source, location, material, and
residual gas composition.
Crystal does not oscillate or
oscillates intermittently (both
in vacuum and in air). Damaged crystal. Replace the crystal.
Existence of electrical short
or poor electrical contacts. Check for electrical continuity
and short in sensor cable,
connector, contact springs,
and the connecting wire
inside the sensor; check for
electrical continuity in
feedthroughs.
NOTE: Spring conditions are observed as part of a routine maintenance. Insufficient
bends or deformities in the spring contacts in the sensor body are common
“crystal problems". Lift each spring up approximately 60°.
Crystal oscillates in vacuum
but stops oscillation after
open to air. Crystal was near the end of
its life; opening to air causes
film oxidation, which
increases film stress. Replace the crystal.
Excessive moisture
accumulation on the crystal. Turn off cooling water to
sensor before opening it to
air; flow hot water through
the sensor when the
chamber is open.
Table 1-2 Symptom - Cause - Remedy Chart (continued)
SYMPTOM CAUSE REMEDY