INFICON IC/5 Thin Film Deposition Controller - Manual (Page 67)

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IC/5 Operating Manual
7 XTAL
This field is subdivided into two categories. The first category, LIFE displays the
crystal life. The IC/5 allows a 1.5 MHz frequency shift on the monitor crystal
corresponding to 100% crystal life. The value shown represents the amount of
crystal life consumed. The amount of useful crystal life is highly dependent on
the nature of the material being deposited as well as deposition conditions. The
second category is a measurement of the crystal activity, ACT. Activity is a
measure of the sensor’s “health” or ability to conduct current. The values range
from a maximum of 650 (healthiest) to a minimum of 0 (least healthy).
The activity value is useful for predicting when a crystal needs to be replaced.
If a crystal is about to fail, its series resistance will increase, allowing less
current to flow through the crystal and hence the activity value will decrease.
The closer the activity value is to zero the more imminent a crystal failure.
It also can be used to gauge the health of the sensor head electrical contacts.
For example, if a new monitor crystal is placed into the sensor head and has a
crystal life of near 0%, but the activity value for this crystal is lower than 400,
this indicates the sensor head or in-vacuum cable is in need of repair.
8 RATE
This field is also subdivided into two categories. The first category is AVE. The
value displayed here is the sensor’s average rate. This average is calculated
based on a 2.5 second average minus the most recent 0.5 seconds of
information. The second field is RAW representing the instantaneous rate
measurement. These fields are useful in identifying if a sensor’s rate
measurements are becoming erratic. N/A (not available) will be displayed in
these fields for sensors not in use.
9 Function Key Definition area
10 Message area
11 Aggregate Rate, Thickness, and Power display area