INFICON STC-2000A Thin Film Deposition Controller Operating Manual - Manual (Page 28)

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STC-2000A DEPOSITION CONTROLLER
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solenoids, etc. The card IDs (software addresses) of the PCBs (sensor, input, output cards) are not unique
within their PCB types nor are they programmed by hardware or software. It is the location into which
they are connected that gives them their unique identity (software address).
A communication port is used to interrogate the STC-2000A. By using a set of commands, various
information can be downloaded or uploaded, front panel control can be simulated, process control can be
modified/stopped/started/driven, etc.
There are also other useages and subuseages. Some other useages would be test mode and rate sample/hold
mode.
Multiple material co-deposition is also possible but with a different Sycon product described in its own
manual.
SECTION 2.2
how does it work ?
Be forewarned that the general information contained herein is meant only as an overview of the system.
The information presented here does not adequately describe the many hazardous situations that could
occur brought about by the incorrect constellation of valve states, temperatures, pressures and voltages.
The system needs to have safety provisions should inadvertent human intervention cause changes or should
a power failure of any or all parts of the system occur. Safety concerns include electrocution and
explosion.
A generalized, simple, thin film vacuum deposition system (using physical vapor deposition
techniques) needs a number of components. A vacuum chamber provides the space and environment in
which the deposition process will occur. A vacuum is necessary to provide a decreased potential for atomic
collisions and contamination (better dispersion with less impurities). Vacuum pumps are needed: roughing
pump (starts vacuum), cryogenic pump (provides final high vacuum), etc. Relays, valves and solenoids to
control the pumps, pump valves and to seal/vent the chamber are needed. A vacuum gauge is needed to
monitor the chamber vacuum. Additional vacuum gauges may be used to monitor other points in the
vacuum system. At the appropriate pressures, the system user can close/open valves, start the deposition
process, etc. A heat/excitation source (electron beam, resistive filament, etc.) to react with the source
material to be deposited, the source material itself, a boat, coil or crucible, etc. into which the source
material is placed, a power supply for the heat/excitation source, and the target (substrate) material are all
needed. A source of water for cooling various components is also needed. An air compressor is necessary
to activate solenoid controlled valves, shutters, etc. Various traps can be used to keep gases clean. Crystal
sensor[s] and attendant oscillator need to be connected to the STC_2002. Shutters are usually placed to
shield the crystal sensors or the source material's evaporant stream, at least during process startup. The
STC-2000A typically acts to tie most, or all, of these elements together to control the deposition process.
For e-beam use, a sweeper control unit may also be needed. In multipocket (multiple material sources) e-
beam gun systems, a pocket indexer or rotator would also be needed.
The roughing pump creates a low vacuum in the chamber first through the open gate valve, the cryopump
and the open rough valve with the purge valve closed. When the desired level of low vacuum is attained,
the roughing pump is powered off as the rough valve between the cryopump and roughing pump is closed.
The cryopump begins to pump the chamber to a higher vacuum (by condensing gas molecules on an
extremely cold surface of a container). When the cryopump reaches saturation, the gate valve is closed and
the purge valve is opened so that the cryopump can be regenerated (a heater may be needed). After
cryopump regeneration is complete (condensed gases have been dissipated), the purge valve is closed, the
gate valve is opened and the pump-down to a higher vacuum using the cryopump continues.
SECTION 2.XX page 28 of 292