INFICON SQC-310 Thin Film Deposition Controller - Manual (Page 59)

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SQC-310 Operating Manual
3.10.2 Film Deposit Controls Menu
The Deposit Controls Menu, see Figure 3-13 , contains the settings used to control
shutters and instrument response during error conditions.
Figure 3-13 Deposition Controls Menu
Shutter Delay: It is often desirable to obtain deposition control before the substrate
shutter opens. Enabling shutter delay requires that the system reach a specific
capture accuracy before the shutter opens. If the capture accuracy is not reached
within the shutter delay time, the process halts. Otherwise, the substrate shutter
opens and deposition begins when control accuracy has been maintained for 5
seconds. The thickness reading is zeroed at the end of the shutter delay period.
Capture: The control accuracy (%) that must be reached to end the shutter delay.
Control Delay: It is common to see a negative rate spike at the beginning of the
Deposit state when using a source or sensor with a shutter. This is due to the
sudden change in temperature that the crystal is exposed to when the shutter
opens. When the Control Delay function is used, the control loop will ignore the rate
for a set amount of time at the beginning of the Deposit state. This helps to
eliminate overcompensation by the control loop due to rate spikes when the sensor
or source shutter opens. The Control Delay setting is the amount of time the
SQC-310 will wait before the control loop takes over.
Control Error: If the control loop cannot maintain the desired deposition rate, due
to loss of source material, excess rate ramps, or equipment malfunction, a control
error occurs. The error condition can be ignored, the process stopped (output
power to 0%), or the output power held at the same level as when the error
occurred. If hold is selected, PID control is abandoned, but the process will
continue to be monitored for thickness setpoint.