INFICON Crystal 12 Sensor - Manual (Page 31)

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Crystal12 Sensor Operating Manual
2.3.1 Crystal Sensor Installation
Generally, install the sensor as far as possible from the evaporation source (a
minimum of 10" or 25.4 cm) while still being in a position to accumulate thickness
at a rate proportional to accumulation on the substrate.
Figure 2-2 shows proper
and improper sensor positioning.
Figure 2-2 Sensor Installation Guidelines
To guard against spattering, use a source shutter to shield the sensor during the
initial soak periods. If the crystal is hit with even a minute particle of molten
material, it may be damaged and stop oscillating. Even in cases when it does not
completely stop oscillating, it may immediately become unstable, or shortly after
deposition begins instability may occur.
Plan the installation to insure that there are no obstructions blocking a direct path
between the sensor and the source.
Install sensors in such a manner that the center axis of the crystal is aimed directly
at the source to be monitored. Verify that the angle of the sensor location (with
reference to the source) is well within the evaporant stream.
Attach the sensor with a mounting bracket anchored to the deposition chamber.
With the bracket in place, temporarily position and attach the sensor head as
outlined in the general guidelines above. Next, temporarily install the feedthrough.
You may now form, measure, and mark the sensor’s tubes (use the bending tool
(IPN 750-036) to form tubes in the system).
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