US 11,887,820 B2
Sector shunts for plasma-based wafer processing systems
Stephen E. Savas, San Jose, CA (US); and Alexandre De Chambrier, San Jose, CA (US)
Assigned to COMET TECHNOLOGIES USA, INC., San Jose, CA (US)
Filed by COMET TECHNOLOGIES USA, INC., San Jose, CA (US)
Filed on Jan. 8, 2021, as Appl. No. 17/145,221.
Claims priority of provisional application 62/959,636, filed on Jan. 10, 2020.
Prior Publication US 2021/0217593 A1, Jul. 15, 2021
Int. Cl. H01J 37/32 (2006.01)
CPC H01J 37/32568 (2013.01) [H01J 37/3255 (2013.01); H01J 37/32183 (2013.01); H01J 37/32577 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A radio frequency plasma processing system comprising:
a reaction chamber receiving radio-frequency power exciting a plasma;
an electrode having an electrode symmetry axis, the electrode powering the plasma disposed inside in the reaction chamber as the plasma performs a plasma process on a wafer;
a plurality of sensors disposed in the reaction chamber positioned adjacent to and spaced around a perimeter of the electrode at a gap from the electrode;
each sensor connected to a respective variable impedance circuit; and
an automated controller varying each variable impedance circuit providing a specified shunt impedance between each sensor and electric ground.