INFICON XTC/C Thin Film Deposition Controller - Manual (Page 21)

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XTC/C - XTC/2 Operating Manual
1.2 Introduction to the Instrument
The XTC/2 and XTC/C are quartz crystal transducer type deposition process
controllers with three layer capability. They are readily connected to interact
with and control the other instruments associated with a vacuum coating plant
of moderate complexity. These instruments incorporate the patented (US
#5,117,192—May 27, 1992) ModeLock measurement system. This innovative
system provides process security, measurement speed and precision at a level
that no active oscillator based instrument can provide.
The bright Liquid Crystal Display of the XTC/2 is easily read and keeps the
operator continuously informed with pertinent deposition data including rate,
thickness, phase, rate deviation and elapsed time. Special messages such as
Stop, Crystal Fail or Time-Power are clearly presented to reduce operator
uncertainty and eliminate the possibility of costly mistakes.
The XTC/C is a variant of the XTC/2 that has a limited front panel. Instead of
an LCD display, it has 8 LED type status indicators that indicate process status
and instrument functional status. It is primarily designed for use in vacuum
coating plants that have a computer based central controller. The original
equipment manufacturer (OEM) will design a custom user input-output system
through his system controller. Once programmed and started, the XTC/C will
essentially run as independent of the central controller as is desired. The
deposition layer can complete without further intervention, freeing the central
controller for other tasks. Status and data may be queried as frequently as is
desired, however.
Interaction with the coating system for both units is multifaceted. All units come
with RS232 and support data rates to 9600 baud. The SECSII protocol is
supported. The optional computer interface is IEEE-488. The instrument is
configured to sequentially control two separate deposition sources with 15 bit
resolution using either PID or integrating type controller algorithms. Twelve
relays are used to manipulate various external devices such as source and
sensor shutters, heaters or valves. Lower power outputs are used to control the
position of multi-hearth crucibles. There are eight input lines to provide the
ability to sense and react to discrete external signals.
There are numerous special control functions for accommodating the needs of
the deposition process. Full predeposit processing is provided, including
shutter delay which allows the establishment of the desired rate prior to opening
the substrate shutter. A Rate Ramp allows the deposition rate to be changed
during the deposit phase. The RateWatcher feature allows the deposition
stream to be periodically sampled, extending the life of the crystal.
These instruments are fully compatible with the complete family of INFICON
transducers, including Dual and CrystalSix®.