| 摘要 |
Appts. for controlling a cathode sputter magnetron device to provide uniformity of material supplied to a workpiece (14) over the linves of geometrically spaced targets (22,23) each subjected to a separate plasma discharge confined to the target by a separate magnetic field. Control appts. senses target erosion condition and in response to this controls the relative powers of the separate discharges so that the powers change as a function of the erosion condition. The impedances of the discharges are pref. controlled by varying the magnetic field. Pref. each field is derived by an electromagnet (29,30) and the impedance is sensed and compared with a set value to derive an error signal to control current applied to the electromagnet.
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