INFICON MDC-260 Thin Film Deposition Controller - Manual (Page 115)

MDC-260 DEPOSITION CONTROLLER
SYSTEM INSTALLATION 9-3
connector to the sensor head. The feedthrough has a standard BNC connector for
the coaxial connection to the sensor oscillator.
9.5 SENSOR CRYSTAL REPLACEMENT
The Next Generation Cool Drawer™ simplifies the replacement of the sensor
crystal. However, since the system relies on the sensor crystal to perform
accurate measurements, care must be taken to maintain the cleanliness of the
crystal during installation. Please read the following Section 9.5.1 and 9.5.2
before attempting to replace the crystal.
Removal and replacement of sensor crystals should be performed in a clean
environment. An isolated clean workbench is recommended for crystal
replacement.
9.5.1 CRYSTAL CARE AND HANDLING
It is essential that a sensor crystal is clean and free of contamination that
undermine the quality of the crystal inducing errors in the measurements or
shortening its useful life. The following guidelines are recommended for general
handling of the sensor crystals.
♦ Keep the crystals in a clean environment. Store them in their original
package until use.
♦ Never handle the crystals with bare hands.
♦ Always use plastic tweezers around the edge of the crystal during handling.
♦ Do not touch the center of a sensor crystal, as any oil, dirt, dust, or scratches
will quickly degrade the quality of the crystal.
♦ When using a chemical agent to clean the crystal, ensure that the crystal
electrode material(s) will not be damaged by the chemical.
♦ Never use cleaner that will etch the quartz surface.
♦ Always rinse with deionized water, or another appropriate pure liquid,
before drying the crystal.
♦ Always use a flow of dry, oil-free, non-reactive gas (e.g. filtered nitrogen) to
blow-dry the crystal. It is better to chase liquid off the crystal than to let it
evaporate off the crystal.
♦ Never wipe the crystal – even soft, lint-free cloth will scratch the crystal.
♦ When handling the drawer always hold it by the edges to avoid touching the
crystal surface.
9.5.2 CRYSTAL REPLACEMENT PROCEDURE
1. Using your thump and index fingers, gently squeeze the sides of the retainer at
mid section then lift it up, away from the drawer, as shown in Figure 9-1.
2. Holding the drawer by the handle and turn it up side down to remove the spent
crystal.