INFICON MDC-360 Thin Film Deposition Controller - Manual (Page 50)

MDC-360 DEPOSITION CONTROLLER
4-18
used. A list of the more commonly used film densities is presented in Table 10-1.
.99 gm/cm
2
/sec)
y the MDC-360 in order to
en the sensor crystal is heavily
ial is known, it can be entered
es the acoustic impedance of the
ained from The Handbook of Physics or
wave impedance should be used. The
alculated from the shear modulus or the
As a first approximation, bulk material density can be used in programming.
Empirical calibration of this parameter is described in Section 10.6.1.
7. Acoustic Impedance (0.50 to 59
This parameter is the acoustic impedance of the material. The acoustic
impedance of the deposited film is required b
accurately establish the sensor scale factor wh
loaded. If the acoustic impedance of the film mater
directly in units of 10
5
gm/cm
2
sec. In most cas
bulk material can be used and can be obt
other source of acoustic data. The shear
shear wave acoustic impedance can be c
shear wave velocity and the density by using the following equation:
AI C G
= ⋅ = ⋅ ρ ρ
Where:
AI= Acoustic Impedance
ρ
= Density (gm/cm
3
)
C= Transverse (shear) wave velocity (cm/sec)
osited
a technique for empirically determining
ensor crystal is not heavily loaded,
using the acoustic impedance of quartz
e deposition system
deposition rate on the substrates and the
eter is entered in percent units and 100%
n:
G= Shear Modulus (dynes/cm
2
).
A list of the acoustic impedance and density of the more commonly dep
materials is presented in Table 10-1 and
this parameter is presented in Section 10.6.3.
In many cases and particularly if the s
sufficient accuracy can be achieved by
which is 8.83 X 10
5
gm/cm
2
sec.
8. Tooling Factor (10.0 to 499.9%)
This parameter is the tooling factor for the primary sensor. The Tooling Factor
parameter is used to compensate for geometric factors in th
which result in a difference between the
rate on the sensing crystal. This param
corresponds to equal rates at the substrate and at the sensing crystal. To a first
approximation the tooling factor can be calculated using the following equatio
Tooling
dc
⎛ ⎞ 2
ds
%
=
⎝
⎜
⎠
⎟ ⋅100
where:
dc= Distance from source to crystal.
PROGRAMMING AND CONTROLLER SETUP