Patent ID: 7906033

Claim:
A plasma etching method for etching a workpiece, comprising: providing a high frequency coil antenna comprising first and second winding segments, winding around and respectively facing toward a first height portion and a second height portion of an outer peripheral surface of a reaction tube and electrically connected to a power supply and a ground to generate a plasma inside the reaction tube, and a third inclined segment, successively extending between the first and the second winding segments in an inclined manner, winding around and facing toward a portion extending between the first and second height portions of the outer peripheral surface of the reaction tube to produce a relatively large uniformly distributed capacitive coupling with the reaction tube, said third segment being closer to the outer peripheral surface of the reaction tube than the first and second winding segments; placing the workpiece in a processing chamber defined by the reaction tube made of a dielectric material; introducing a processing gas into the processing chamber; supplying high frequency power to the high frequency coil antenna winding around the outer peripheral surface of the reaction tube, the high frequency antenna having the third segment that faces the outer peripheral surface of the reaction tube and has a capacitive coupling with the outer peripheral surface of the reaction tube that has a greater magnitude relative to a magnitude of a capacitative coupling of the first and second winding segment of the high frequency antenna; and generating a plasma in the processing chamber to etch the workpiece by the supplied high frequency power while rotating the third segment of the high frequency antenna relative to the reaction tube along the outer peripheral surface of the reaction tube, and while maintaining a distance between the outer peripheral surface of the reaction tube and the third segment to be less than a distance between the outer peripheral surface of the reaction tube and the first and second winding segments.