Magnetic field control system

A magnetic field controller, comprising:

• a first terminal coupled to a direct current (DC) voltage source;
• a second terminal communicatively coupled to one or more vacuum chambers, each of the one or more vacuum chambers including a processing zone for processing a substrate using plasma;
• a third terminal communicatively coupled to one or more magnetic field sources, each of the one or more magnetic field sources configured to generate one or more active magnetic fields through the processing zone of at least one of the one or more vacuum chambers;
• a fourth terminal communicatively coupled to one or more magnetic field sensors configured to detect a signal representing the one or more active magnetic fields;
• and
• processing circuitry communicatively coupled to the first, second, third, and fourth terminals, wherein to perform adjustment of the one or more magnetic field sources, the processing circuitry is configured to:
• determine a target value corresponding to at least one characteristic of the one or more active magnetic fields;
• set an initial current through the one or more magnetic field sources, the initial current corresponding to the target value;
• and
• adjust a subsequent current through one or more coils of the one or more magnetic field sources based on a difference between a coil current of the one or more coils and the initial current corresponding to the target value;
• and
• update the target value based on the difference to generate an updated target value.

A method of controlling a magnetic field in a vacuum chamber, the method comprising:

• determining a target value corresponding to at least one characteristic of one or more active magnetic fields through a processing zone of the vacuum chamber;
• setting an initial current through at least one magnetic field source to generate the one or more active magnetic fields, the initial current corresponding to the target value;
• adjusting a subsequent current through at least one coil of the at least one magnetic field source based on a difference between a coil current of the at least one coil and the initial current corresponding to the target value;
• and
• updating the target value based on the difference to generate an updated target value.