Patent ID: 9275839
Filing Date: 2016-03-01
CPC Classification: H01J

Claim Text:
1. A plasma chamber for use with a reactive gas source, comprising: a gas inlet that receives a process gas; at least four legs including at least an upper leg and two vertical legs forming a toroidal plasma channel, each leg having a substantially circular cross-sectional area; and a plenum above the upper leg and the two vertical legs that introduces the process gas into the plasma channel, the plenum comprising: a first group of holes distributed along an elongated portion of the upper leg for introducing the process gas into the plasma channel to provide initial helical gas rotations within the upper leg toward each vertical leg, and for each vertical leg, a second group of holes distributed along a portion of the vertical leg for introducing the process gas into the plasma channel to provide a second helical gas rotation within each vertical leg, wherein (1) the first group of holes are angled substantially tangential to an inner surface of the upper leg at between 30 degrees and 90 degrees relative to an axial direction of the upper leg and between 45 degrees and 90 degrees relative to a direction perpendicular to the axial direction and (2) the second group of holes are angled substantially tangential to an inner surface of respective vertical leg at between 30 degrees and 90 degrees relative to the axial direction and between 45 degrees and 90 degrees relative to the perpendicular direction, the first and second groups of holes are oriented to allow the second helical gas rotation within each vertical leg to coherently merge with the initial gas rotations.