INFICON SQM-160 Thin Film Deposition Monitor - Manual (Page 41)

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SQM-160 Operating Manual
3.13 Rate Sampling
In Rate Sampling mode, the SQM-160 opens a sensor shutter for a fixed time to
"sample" the process rate, then closes the shutter and "holds" the last rate reading
for a fixed time. While the shutter is closed (hold mode), the SQM-160 calculates
thickness based on the last sampled rate.
NOTE: Rate sampling can significantly extend crystal life in a high deposition rate
process. However, unless the process is very stable, the thickness
calculation during hold mode may be incorrect. Do not use rate sampling
if your rate varies during deposition.
To program the SQM-160 for Rate Sampling:
1 Press Program to enter Program mode.
2 Press Prev to enter the System Menu.
3 Press Next until SAMPLING is shown.
4 Turn the Control Knob right to turn ON rate sampling. Press the Control Knob
to accept the value.
5 Press Program to exit the System Menu and return to normal mode.
6 Press Program to re-enter Program mode.
7 Use the Control Knob to scroll to the desired Film # (1-9), then press the Control
Knob or Next to enter the film parameter menu for the selected film.
8 Press Next until SAMPLE is shown.
9 Use the Control Knob to set the sample time period. Press the Control Knob to
accept the sample value and display HOLD.
10 Use the Control Knob to set the hold time period. Press the Control Knob to
accept the Hold value.
11 Press Program to exit the Film Menu and return to normal mode.
NOTE: The rate sampling relay is a dual function relay. It can be programmed
either to sample rate or to close when a programmed thickness is reached.
See
section 3.15, Thickness Setpoint, on page 3-13 . See 3.20, Operation ,
for relay wiring.