Abstract: Disclosed is a regulator circuitry (stabilizer) for controlling the output of an RF generator according to a programmable input signal. A power stage is responsive to the selected value of the programmable input signal to drive the RF generator at the desired power level. A forward power feedback control circuit monitors and controls the power output stage so that the desired RF output level is maintained at a constant level. In this particular mode of operation, RF output power is maintained constant and therefore independent of variations in gain due to temperature changes and other parameters which could effect the overall transfer function of said generator (and including mismatch of the generator into the load).

Abstract: Disclosed is a detector for determining the location of wafers moving in a sputtering system, for example, to and from the sputtering chamber where the wafers are processed, including a capacitive transducer, located in the path of travel of the wafers, to which is coupled an oscillator supplying a constant current thereto. This current is detected by a sensor, whose output is processed and applied to a comparator. The comparator is preferably preset to supply a digital "0" when the current through the transducer is at a static or no-wafer condition, and a digital "1" when the capacity of the transducer changes due to the presence of a wafer in close proximity to the transducer which is sensed as an increase in current which is reflected as a change of voltage level applied to the comparator.

Abstract: Circuitry for controlling the power output of an R.F. generator for regulating the forward power transmitted into a load of varying impedance, such as an R.F. sputtering target, and for limiting reflected power to a safe predetermined level. Forward power is controlled by circuitry that compares the voltage across the target with a predetermined reference voltage and the amplified output is applied to the signal generator control circuitry. Reflected power is measured by a sensor that outputs a proportional D.C. signal that is compared with a predetermined threshold voltage. Whenever the reflected power signal exceeds this threshold, it removes the effect of the target voltage input signal so that the amplified control signal to the R.F. generator is a function only of the reflected power.

Abstract: A high power D.C. supply regulated for constant output power to be dissipated in varying loads such as encountered in cathode sputtering systems. A.C. input power is rectified to produce the desired D.C. The output D.C. voltage and load current are measured and a voltage signal proportional to their product is compared with a D.C. input control signal. The comparator "error" output signal controls a pass element that varies a D.C. current through saturable reactors in the A.C. input power lines to regulate the D.C. power into the load. The supply includes a limiting feature that is adjustable to a desired threshold level for limiting D.C. output power, voltage, and/or current so that the limiter will take control from the comparator to hold the supply output at a safe level.