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INFICON IC6 Thin Film Deposition Controller User Manual

Page 235

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IC6 Operating Manual

11.1.1 IC6 Parameters and Corrections for

Multiple Sensor Operation

Figure 11-2 Multipoint display

AGGREGATE RATE

The Aggregate Rate calculation is based on:

The rate information acquired by each sensor in use.

A weighting factor that reflects the relative importance of each sensor's
information.

A sensor tooling factor that corrects for any relative difference in flux
distribution reaching the sensors.

The aggregate rate is calculated from a combination of the above information
into a weighted average.

If a sensor fails during deposition, a sudden change in the aggregate rate may
occur due to this sensor's rate information being lost. An aggregate multiplier
is calculated to correct for this sudden change. The aggregate multiplier is
based on the average deposition prior to sensor failure. An average aggregate
rate is calculated both with and without the newly failed sensor. The ratio of the
two is used as a multiplier for the rest of this layer's deposition. This removes
any sudden jump in the aggregate rate at the time of sensor failure. After this
layer finishes, the aggregate multiplier is removed.