INFICON SQM-242 Thin Film Deposition Controller Card Operating Manual - Manual (Page 64)

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SQM-242 Operating Manual
7.2 Replacing the Crystal
CAUTION
Always use clean nylon lab gloves and plastic tweezers
for handling the crystal (to avoid contamination which
may lead to poor adhesion of the film to the electrode).
Do not rotate the ceramic retainer assembly after it is
seated (as this will scratch the crystal electrode and
cause poor contact).
Do not use excessive force when handling the ceramic
retainer assembly since breakage may occur.
NOTE: Certain materials, especially dielectrics, may not adhere strongly to the
crystal surface and may cause erratic readings.
NOTE: Thick deposits of some materials, such as SiO, Si, and Ni will normally peel
off the crystal when it is exposed to air, as a result of changes in film stress
caused by gas absorption. When you observe peeling, replace the
crystals.
7.2.1 Front Load
Follow the procedure below to replace the crystal in the Front Load sensor: (see
Figure 7-1 )
1 Gripping the crystal holder with your fingers, pull it straight out of the sensor
body.
2 Gently pry the crystal retainer from the holder (or use the Crystal Snatcher; see
Figure 7-6 on page 7-15 ).
3 Turn the retainer over and the crystal will drop out.
4 Install a new crystal, with the patterned electrode face up.
5 Push the retainer back into the holder and replace the holder in the sensor
body.