K465i Operations and Maintenance
P/N 1212831 Rev C
Page 4-35
Copyright
©
2012
Veeco Instruments, Inc. Confidential
All Rights Reserved
SELECTING TEMPERATURE CONTROL MODES
This procedure is used to select the temperature control mode for layers of a growth run.
This is done using the Nexus recipe software. Switching between temperature control modes
must be accomplished in at least three steps within the recipe. Figure 4-8 provides a sample
of switching control modes in a recipe. Control modes are switched between layers 3 - 5.
When switching from thermocouple (T/C) mode to pyrometer control (PYRO) mode or vise
versa, it is necessary to first switch the temperature controllers for the filament power
supplies. T/C and Pyro settings are configured in
layers
. Between a T/C layer and a Pyro
layer you must have a
T/C switch
layer. This configuration allows you to implement T/C
temperatures as setpoints in the switch layer, and the equivalent Pyro temperatures as
setpoints in the next layer, without being forced to ramp.
All PID tables for both of the loops are stored in the Eurotherm software.
Note:
There is additional logic for the PID to prevent wind-up of inactive loops.
Caution:
When writing a recipe it is important to remember that the pyrometers
can not read temperatures below 450
o
C. Always start a recipe with a layer or layers with
temperature under T/C control to bring the wafer temperature above 500
o
C prior to
engaging PyroControl mode.
Note:
Refer to the
for instructions on how to write a recipe.
Procedure 4-18: Temperature Control Mode Selection Procedure
1. Open the recipe screen in the Nexus software.
2. Add the desired controls and number of layers to the recipe following the procedures outlined in the
Nexus Software Manual.
3. Select the Filament Mode cell in the layer to be setup.
4. Click down arrow in cell and select the desired temperature control mode (Figure 4-8).
5. Verify that the cell reflects the desired temperature control mode.
6. Select the Mode cell in the layer to be set up.
7. Click the down arrow in the cell and select desired PID mode.
8. Verify that the cell reflects the desired PID mode.
