INFICON Q-pod Thin Film Deposition Monitor - Manual (Page 52)

5 - 2
IP
N 07
4-
54
7-
P1
B
Q-pod Operating Manual
where:
D
1
= Initial density setting
T
x
= Thickness reading on Q-pod
T
m
= Measured thickness
7 A quick check of the calculated density may be made by programming the
Q-pod with the new density value and observing that the displayed thickness is
equal to the measured thickness, provided that the Q-pod'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
.
5.3 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 Q-pod
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.
5.4 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
-------
 
 
 
=