INFICON XTC/C Thin Film Deposition Controller - Manual (Page 123)

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XTC/C - XTC/2 Operating Manual
For example, if the Q factor parameter has a value of 5 and the rate control
varies by more than ±12.5% this causes the Q counter to increment. When it
reaches the value of 50 the crystal is "Soft Failed" due to the crystal quality
algorithm. This "Q" failed crystal can be cleared by re-entering the parameter
value 5 for the Q factor parameter or by changing it to another value.
4.7 Rate Ramps
Each film program includes a rate change parameter. It may be used to
generate a precise linear variation in the evaporation rate. "Rate Ramps"
execute during the deposit state of the film. They are initiated when the THICK
STP parameter of the film program is reached. If the rate ramp state terminates
before the film reaches FINAL THK, the instrument will return to the deposit
phase.
The slope of a rate ramp is determined by the following equation: delta rate per
sec = (NEW RATE - DEP RATE) divided by RAMP TIME. If a ramp parameter
is changed during the ramp, a new slope will be calculated, taking into
consideration the time the ramp has already been in process.
4.7.1 Rate Ramp to Zero Rate
It is sometimes desirable to ramp to zero rate for alloy phasing purposes,
completing the film processing as if a final thickness had been achieved. Rate
ramps, however, are ordinarily deleted by entering zero for the NEW RATE.
Therefore, in order to implement this type of film termination, program the NEW
RATE value of the rate ramp to 0.1 Å/sec. When this rate value is achieved, the
film program will proceed as if a FINAL THK limit had been reached.
While a rate ramp is being processed, the DEP RATE parameter’s internal
value is continuously updated to match the slope of the Rate Ramp.
NOTE: If the TIME-POWER state is entered, a rate ramp will not be executed;
with the film completing at the programmed FINAL THK.
4.8 Use of the Hand Controller (Option)
A hand held controller is provided as an option. The controller serves as a wired
remote to manually control power, switch crystals and produce a STOP.
The controller is attached to the instrument with a coiled cord and attaches with
a modular plug to the front panel of the instrument. The POWER/STOP switch
located at the top of the controller is asymmetrical to increase awareness of the
direction of power increment and decrement.
Power is affected (only when in Manual mode) by moving the POWER/STOP
switch laterally. A STOP is produced by plunging the POWER/STOP switch
down.