INFICON STM-2 USB Thin Film Rate/Thickness Monitor - Manual (Page 88)

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STM-2 Operating Manual
6 Determine the new Density value with equation [1] :
[1]
where:
D
1
= Initial Density setting
T
x
= Thickness reading on STM-2
T
m
= Measured thickness
7 A quick check of the calculated Density may be made. If the STM-2 thickness
has not been zeroed between the test deposition, enter the calculated Density.
Program STM-2 with the new Density value and observe whether the displayed
thickness is equal to the measured thickness.
NOTE: Due to variations in source distribution and other system factors, it is
recommended that a minimum of three separate evaporations be made, to
obtain an average value for Density.
NOTE: Slight adjustment of Density may be necessary, in order to
achieve T
x
= T
m
.
7.3 Determining Tooling
1 Place a test substrate in the substrate holder of the system.
2 Make a short deposition and determine actual thickness.
3 Calculate Tooling from the relationship shown in equation [2] :
[2]
where
T
m
= Actual thickness at substrate holder
T
x
= Thickness reading in STM-2 software
TF
i
= Initial tooling factor
4 Round percent tooling to the nearest 0.1%.
5 When entering this new value for Tooling into the program, if calculations are
done properly, T
m
will equal T
x
.
NOTE: To account for variations in source distribution and other system factors,
obtain an average value for Tooling, using a minimum of three separate
evaporations.
Density g cm
3
   D
1
T
x
T
m
-------
 
 
 
=
Tooling (%) TF
i
T
m
T
x
-------
 
 
 
=