INFICON SQM-160 Thin Film Deposition Monitor - Manual (Page 81)

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SQM-160 Operating Manual
2. Crystal ceases to oscillate
during deposition before it
reaches the end of its normal
life. a. Crystal struck by
particulate or spatter from
molten source. a. Thermally condition the
source thoroughly before
deposition, use a shutter to
protect the crystal during
source conditioning.
b. Material on crystal holder
partially masking crystal
cover aperture. b. Clean crystal holder.
c. Existence of electrical
short or open condition. c.Using an ohm meter or
DMM, check for electrical
continuity in the sensor
cable, connector, contact
springs, connecting wire
inside sensor, and
feedthroughs.
d. Thermally induced
electrical short or open
condition. d. See 2c above.
NOTE: Crystal life is highly dependent on process conditions of rate, power radiated from
source, location, material, and residual gas composition.
3. Crystal does not oscillate
or oscillates intermittently
(both in vacuum and in air.) a. Intermittent or poor
electrical contact (contacts
oxidized.) a. Use an Ohm meter or
DMM to check electrical
continuity, clean contacts.
b. Leaf springs have lost
retentivity (ceramic retainer,
center insulator.) b. Carefully bend leaves to
approx. 45° on ceramic
retainer and 60° inside the
sensor head.
c. RF interference from
sputtering power supply. c. Verify earth ground, use
ground strap adequate for
RF ground, change location
of oscillator and cabling away
from RF power lines.
d. Cables not connected, or
connected to wrong sensor
input. d. Verify proper connections,
and inputs relative to
programmed sensor
parameter.
Table 6-2 Troubleshooting Sensors (continued)
SYMPTOM CAUSE REMEDY