INFICON Sputtering Sensor - Manual (Page 19)

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Sputtering Crystal 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). Crystal not properly seated. Check and clean the crystal
seating surface of the crystal
holder.
Excessive heat input to the
crystal. If heat is due to radiation
from the evaporation source,
move sensor further away
from source.
No cooling water. Check cooling water flow rate
(refer to
see page 1-1 ).
RF interference from the
sputtering power supply. Check groundings; change
location of instrument and
oscillator; connect
instrument to different power
line.
Poor thickness
reproducibility Material does not adhere to
the crystal. Check the cleanliness of the
crystal surface; evaporate an
intermediate layer of proper
material on the crystal to
improve adhesion.
Large drift of thickness
reading (greater than 200Å
for density reading = 5.00
gm/cc) after termination of
sputtering. Crystal heating due to poor
thermal contact. Check and clean the crystal
seating surface.
External magnetic field
interferes with the sensor
magnetic field. Rotate the sensor magnet to
a proper orientation with
respect to the external
magnetic field.
Sensor magnet defective
(cracked or demagnetized) Check sensor magnet field
strength; if a gaussmeter is
available, the maximum field
at the center of the opening
hold should give a reading of
700 gauss or greater.
Table 1-2 Symptom - Cause - Remedy Chart (continued)
SYMPTOM CAUSE REMEDY