INFICON MDC-360 Thin Film Deposition Controller - Manual (Page 125)

MDC-360 DEPOSITION CONTROLLER
10-5 THEORY OF OPERATION
Determine the average film thickness on the test substrates and use the follow
equation to calculate the material's density:
Density = (Displayed Thickness/Average Measured Thickness) * Den
ing
sity(test)
Wh
run
Onc e, the programmed film density is
correct for this particular film.
0,
ine the average film thickness on
the kness differs from the displayed
meter setting used during the calibration
o deposit on the sensor crystal until the crystal health
approaches 50% or until the crystal is approaching the end of its useful life.
Deposit another trial run as above but this time use the manual power mode
inste
atic mode. Measure the average film thickness on the test
substrates and this adjust the acoustic impedance parameter up or down to bring
the
hickness into agreement with the measured thickness. This
calib eter.
The MDC-360 is now fully calibrated for the film in question and should produce
consistent and accurate films.
ere Density(test) is the density parameter setting used during the calibration
.
e the calibration procedure is complet
10.6.2 TOOLING FACTOR
Having established the film density the tooling factor should be established.
Place several test substrates at representative locations in the deposition fixture.
Again deposit a trial film as above using the known film density, and a fresh
crystal unless the programmed acoustic impedance is known to be correct.
Remember to write down the final thickness reading displayed by the MDC-36
as this will be needed in the calculation. Determ
test substrates. If the average measured thic
thickness, use the following equation to calculate the correct tooling factor.
Tooling = (Average Measured Thickness/Displayed Thickness) * Tooling(test)
Where Tooling(test) is the tooling para
run.
10.6.3 ACOUSTIC IMPEDANCE
Establishment of the acoustic impedance requires that the crystal be heavily
loaded. Continue t
ad of the autom
displayed t
rates the acoustic impedance param