| 摘要 |
A non-axisymmetric electromagnet coil used in plasma processing in which at least one electromagnet coil is not symmetric with the central axis of the plasma processing chamber with which it is used but is symmetric with an axis offset from the central axis. When placed radially outside of an RF coil, it may reduce the azimuthal asymmetry in the plasma produced by the RF coil. Axisymmetric magnet arrays may include additional axisymmetric electromagnet coils. One axisymmetric coil is advantageously placed radially inside of the non-axisymmetric coil to carry opposed currents. The multiple electromagnet coils may be embedded in a molded encapsulant having a central bore about a central axis providing the axisymmetry of the coils.
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