INFICON SQM-160 Thin Film Deposition Monitor - Manual (Page 100)

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SQM-160 Operating Manual
where:
D
1
= Initial density setting
T
x
= Thickness reading on SQM-160
T
m
= Measured thickness
7 A quick check of the calculated density may be made by programming the
SQM-160 with the new density value and observing that the displayed
thickness is equal to the measured thickness, provided that the SQM-160's
thickness has not been zeroed between the test deposition and entering the
calculated 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 system's substrate holder.
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 the SQM-160
TF
i
= Initial tooling factor
4 Round off percent tooling to the nearest 0.1%.
5 When entering this new value for tooling into the program, T
m
will equal T
x
if
calculations are done properly.
NOTE: It is recommended that a minimum of three separate evaporations be
made when calibrating tooling. Variations in source distribution and other
system factors will contribute to slight thickness variations. An average
value tooling factor should be used for final calibrations.
7.4 Laboratory Determination of Z-Ratio
A list of Z-values for materials commonly used are available in Table A-1 . For other
materials, Z can be calculated from the following formula:
Tooling (%) TF
i
T
m
T
x
-------
 
 
 
=