摘要 |
The present invention is embodied in a plasma reactor for processing a workpiece such as a semiconductor wafer having an axis of symmetry, the reactor including a reactor chamber with a ceiling having an upwardly extending annular pocket bounded by a pair of circumferential side walls, a pedestal for supporting the workpiece within the chamber under the ceiling, a processing gas supply inlet into the chamber, an RF plasma power source coupled to the pedestal, and a magnetic field source near the ceiling providing a radially symmetrical magnetic field having a magnetic pole of one type facing said inner circumferential wall and a magnetic pole of the opposite type facing said outer circumferential wall so as to apply a magnetic field generally straight across said annular pocket. The straight magnetic field lines of the radially symmetrical magnetic field are generally confined to the annular pocket, penetrating into the chamber to a very shallow depth, if at all, and the height of the ceiling above the workpiece exceeds the magnetic field penetration depth.
|