Owner manual

2 - 6
PN 074-609-P1A
Cool Drawer Single and Dual Sensors Operating Manual
To guard against spattering, use a source shutter to shield the sensor during initial
soak periods. If the crystal is hit with only a very small particle of molten material,
it may be damaged and stop oscillating. Even in cases when it does not completely
stop oscillating, the crystal may immediately become unstable, or shortly after
deposition begins, instability may occur.
Plan the installation to ensure there are no obstructions blocking a direct path
between the sensor and the source.
Install sensors in such a manner that the center axis of the crystal is aimed directly
at the source to be monitored. Verify that the sensor location (with reference to the
source) is well within the evaporant stream. Make sure the sensor is square to the
vapor stream.
NOTE: In many cases installing multiple sensors to monitor one source will
improve thickness accuracy. The rules for multiple sensors are the same
as for a single sensor installation, and the locations chosen must be as
defined above. Consult the monitor or controller manual for more
information regarding the availability of this feature.
A technical description may be found in the 39th Annual Conference Proceedings,
Society of Vacuum Coaters, Reducing Process Variation Through Multiple Point
Crystal Sensor Monitoring, J. Kushneir, C. Gogol, J. Blaise, pp19-23, ISSN
0737-5921 (1996).
2.2.1.1 Sensor Installation Procedure
1 Install all water tube connections, if applicable.
2 Install the sensor and feedthrough assembly into the process system and
secure all retaining hardware.
3 Connect the external water tubes from the feedthrough to the water supply
system and flow controller. Use detachable couples (Swagelok
®
or equivalent)
for external water tube connections.
4 Apply water pressure and verify the water connections.
Because of geometric factors, variations in surface temperature, and differences
in electrical potential, the crystal and substrates often do not receive the same
amount of material. Calibration is required to make sure the thickness indication
on the instrument accurately represents the thickness on the substrates.
Refer to the instrument operating manual for calibration procedures.