INFICON TM-400 Thin Film Deposition Monitor - Manual (Page 62)

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TM-350/400 Operating Manual
5 Alternating between the TOOLING FACTOR and the Modify up and Modify
down key, follow the procedure described in
step 5 on page 9-3 except the
Modify down key is used to lower the displayed thickness to the actual
thickness and the Modify up key is used to raise the display thickness to actual
thickness. Continue until the displayed thickness agrees with the measured
thickness.
6 The Tooling factor should now be correct for the specific application measured.
9.6.3 Acoustic Impedance
1 Use a heavily loaded sensor crystal with a crystal health of about 75%.
2 Deposit on the sensor crystal until the crystal health approaches 50%.
3 Measure the actual thickness of the deposition.
4 Alternating between ACOUSTIC IMPEDANCE and the Modify up and Modify
down keys, follow the procedure described in
step 5 on page 9-3 until the
displayed thickness agrees with the measured thickness. See Table 9-1 .
5 This calibrates the acoustic impedance for the material being deposited.
Table 9-1 Calibration Adjustment
THICKNESS MATERIAL
DENSITY
TOOLING
FACTOR
ACOUSTIC
IMPEDANCE
Display is greater than actual Modify up Modify down Modify down
Display is lower than actual Modify down Modify up Modify up
Table 9-2 Density and Acoustic Impedance Values for Selected Materials
Material Symbol Density
gm/cm^2
Impedance
10^5gm/(cm^2sec)
Aluminum Al 2.70 8.17
Aluminum Oxide Al 2 O 3 3.97 26.28
Antimony Sb 6.62 11.49
Arsenic As 5.73 9.14
Barium Ba 3.5 4.20
Beryllium Be 1.85 16.26
Bismuth Bi 9.8 11.18
Boron B 2.54 22.70
Cadmium Cd 8.64 12.95
Cadmium Sulfide CdS 4.83 8.66