Plasma reactor with spoke antenna having a VHF mode with the spokes in phase

An RF power applicator for use with a plasma reactor capable of processing a semiconductor workpiece, said RF power applicator comprising:

• a conductive enclosure outside of the chamber and overlying the ceiling and having a conductive side wall with a bottom edge supported on said chamber ceiling and a conductive ceiling supported on a top edge of said conductive side wall, and a conductive post extending parallel with said conductive side wall from a center portion of said conductive ceiling toward said chamber ceiling;
• a spoke antenna array comprising:
• (A) a set of inner conductive spokes extending radially outwardly from and electrically connected to said conductive post toward said conductive side wall,
• (B) a set of outer conductive spokes extending radially inwardly toward said conductive post and from and electrically connected to said conductive side wall, whereby said inner and outer sets of conductive spokes are electrically connected together, the combination of said inner and outer set of spokes with said conductive enclosure having a fundamental resonant frequency inversely proportional to the height of said conductive enclosure and the lengths of said inner and outer set of conductive spokes;
• an RF source power generator coupled across said spoke antenna array and having an RF frequency corresponding to said fundamental resonant frequency.

A plasma reactor for processing a semiconductor workpiece, comprising:

• a reactor chamber having a chamber ceiling and a chamber side wall and a workpiece support pedestal within the chamber;
• a process gas conduit and gas distribution orifices facing the interior of the chamber and coupled to the process gas conduit;
• an RF power applicator comprising:
• (A) a set of inner conductive spokes extending radially outwardly from a center axis,
• (B) a set of outer conductive spokes extending radially inwardly from a peripheral circumference;
• an RF source power generator coupled across said RF power applicator and having an RF frequency corresponding to said fundamental resonant frequency;
• and
• (C) an electrically conductive path between a center location of said set of inner spokes and a periphery of said outer spokes, whereby said inner and outer sets of conductive spokes are electrically connected together.