INFICON STC-2002 Thin Film Deposition Controller Operating Manual - Manual (Page 77)

p STC-2002 DEPOSITION CONTROLLER y
SECTION 3.XX e page 75 of 276 ^
The substrate shutter is opened, accumulated thickness set to zero, and the programmed deposition profile
is then started. If the specified rate control accuracy cannot be met within this time limit, the deposition will
be aborted.
____________________________________________________________________
Parameter
SHTR DLY QUALITY
Range is 1 - 50
Units Percent
Shutter Delay Quality
This parameter sets the rate control accuracy that must be established for a period of five seconds
in order to complete the delayed shutter sequence. The maximum accuracy settable is 1 percent of the
desired setpoint. However, this is internally limited to 1 angstrom per second for noise and resolution
restrictions.
____________________________________________________________________
Rate Sampling (has 4 dependent parameters)
This operating mode, when enabled, allows the user to expose the crystal sensor for short periods
of time to the evaporant stream, establish rate control, and then shutter the sensor maintaining the power
setting established during exposure. For relatively stable deposition sources or systems that must maintain
vacuum integrity for long periods of time, crystal sensor life can be greatly extended. Two sampling modes
are available. One has the exposure time strictly time controlled, the other will expose the sensor only long
enough to establish the required accuracy. The exposure period for either mode is also triggerable
externally.
Sample and Hold
Figure- 3.11: Rate Sampling, Sample and Hold Operation.
Parameter
RATE SAMPLING
Rate Sample choices (1 of 3):
OFF
TIMED
MODE
INTELLIGENT MODE
Units None
Enabling Rate Sampling
This switch type parameter will allow the rate sampling parameters to become active and the mode
functional on an individual film basis. If set to Off the parameter window cursor will not access the
associated parameters. If Timed Mode is selected, the crystal sensor will be exposed to evaporant for the
time specified by the sample dwell parameter, and will sample at the interval specified by the sample
interval parameter. If Intelligent Mode is selected, then the duration of the sample will only be long enough
to establish the desired accuracy. [The following 4 parameters are dependent upon this parameter.]
____________________________________________________________________
Parameter
RATE SAMPLE
On/Off Value: Off or On
Units On/Off
Enabling Rate Sampling
This parameter assumes there is a shuttered head connected and that Rate Sampling can be used if
the film parameters are programmed for such. (Without the shutter, deposit would be continuous and negate
the advantage of this feature.) This feature extends the apparent life of the sensing crystal. It is used for
thick coatings or in systems where it is not possible to break vacuum to change the sensing crystal.
Depending on various factors in your particular system, the apparent crystal life can be extended up to 50