Inductively Coupled Plasma Source with Radial Coil Network

An apparatus for generating plasma inductively in a process chamber, comprising:

• a radial coil network with a planar structure configured to inductively generate plasma in the process chamber, including:
• an inner conductor with an open center, wherein a first RF power source is electrically connected to the inner conductor at a first power node and a second RF power source is electrically connected to the inner conductor at a second power node;
• an outer conductor spaced away from and surrounding the inner conductor, wherein a first ground is electrically connected to the outer conductor at a first ground node opposite the first power node and a second ground is electrically connected to the outer conductor at a second ground node opposite the second power node;
• a plurality of branch conductors extending from the inner conductor to the outer conductor, wherein the plurality of branch conductors is distributed uniformly in the radial coil network about the inner conductor and wherein a first branch conductor of the plurality of branch conductors is electrically interposed between the first power node and the first ground node and a second branch conductor of the plurality of branch conductors is electrically interposed between the second power node and the second ground node;
• and
• a plurality of capacitors, wherein at least one capacitor of the plurality of capacitors is electrically interposed into each branch conductor of the plurality of branch conductors and wherein at least one of the at least one capacitor is a variable capacitor.

An inductively coupled plasma (ICP) process chamber for treating substrates with plasma, comprising:

• the ICP process chamber has a chamber body with a lid, a process volume, and a substrate support;
• a first RF power source with a first frequency;
• a second RF power source with a second frequency;
• and
• a radial coil network with a planar structure positioned above the lid of the process chamber and configured to inductively generate plasma in the ICP process chamber, including:
• an inner conductor with an open center, wherein the first RF power source is electrically connected to the inner conductor at a first power node and the second RF power source is electrically connected to the inner conductor at a second power node;
• an outer conductor spaced away from and surrounding the inner conductor, wherein a first ground is electrically connected to the outer conductor at a first ground node opposite the first power node and a second ground is electrically connected to the outer conductor at a second ground node opposite the second power node;
• a plurality of branch conductors extending from the inner conductor to the outer conductor, wherein the plurality of branch conductors is distributed uniformly in the radial coil network about the inner conductor and wherein a first branch conductor of the plurality of branch conductors is electrically interposed between the first power node and the first ground node and a second branch conductor of the plurality of branch conductors is electrically interposed between the second power node and the second ground node;
• and
• a plurality of capacitors, wherein at least one capacitor of the plurality of capacitors is electrically interposed into each branch conductor of the plurality of branch conductors and wherein at least one of the at least one capacitor is a variable capacitor.