6 empirical calibration, 1 material density calibration, 2 tooling factor calibration – INFICON TM-400 Thin Film Deposition Monitor User Manual
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TM-350/400 Operating Manual
9.6 Empirical Calibration
If the density and acoustic impedance of the film material is known, the values
should be entered into the monitor and a trial deposition should be made. If the
displayed thickness does not agree with an independently measured thickness, the
monitor should be calibrated as described below.
To calibrate the monitor, material density, tooling factor and acoustic
impedance must be established in that order. Approximate values should be
used initially.
provides density of some materials, which
should provide guidance as to the approximate density. If the acoustic impedance
is unknown, use the value for quartz 8.83.
9.6.1 Material Density Calibration
1
Use a fresh sensor crystal.
2
Place test substrates as close as possible to the sensor crystal.
3
Make a trial deposition of sufficient thickness to permit adequate precision of
measurement by an independent measuring device.
4
Determine the average thickness on test substrates.
5
If the monitor's displayed thickness is lower than the measured thickness, push
the MATERIAL DENSITY key and then push the Modify down key. If the
displayed thickness is higher than the actual thickness, push the Modify up key.
6
The thickness will be displayed three seconds after the Modify key is released.
Check to see if the thickness displayed now equals the measured thickness. If
it does not, repeat the procedure step 5 until the displayed thickness agrees
with the measured thickness.
7
The programmed material density will now be correct for that particular
material. Record this value for future use.
9.6.2 Tooling Factor Calibration
1
Use a fresh sensor crystal
2
Place test substrates in a location which is representative of where the
production substrate will be located.
3
Make a trial deposition with the known material density as determined above.
4
Determine the average thickness on the test substrates with an independent
thickness measuring device.