US 12,362,136 B2
Apparatus and method for measuring pedestal voltage uniformity in plasma processing chambers
Stephen Savas, Pleasanton, CA (US)
Filed by Stephen Savas, Pleasanton, CA (US)
Filed on Mar. 22, 2023, as Appl. No. 18/124,586.
Claims priority of provisional application 63/322,232, filed on Mar. 22, 2022.
Prior Publication US 2023/0386780 A1, Nov. 30, 2023
Int. Cl. H01J 37/244 (2006.01); H01J 37/32 (2006.01)
CPC H01J 37/244 (2013.01) [H01J 37/32091 (2013.01); H01J 2237/24564 (2013.01); H01J 2237/3323 (2013.01); H01J 2237/3343 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An apparatus for measuring RF voltage at an exposed pedestal surface of a plasma processing chamber configured to operate at an RF operating frequency, said apparatus comprising:
an electrically conducting top plate physically supported above said exposed pedestal surface;
said electrically conducting top plate electrically connected to a ground,
wherein said electrically conducting top plate is physically supported above said surface, and is configured parallel to said surface, by a plurality of supports;
a plurality of resistive elements, each having resistive impedance at said RF operating frequency of said plasma processing chamber, are configured in electrical contact with said top plate, and physically contact said exposed pedestal surface;
at least one capacitively coupled voltage sensor, positioned below said electrically conducting top plate is configured to be in contact with said exposed pedestal surface and connect to a lead that passes through said conducting top plate;
said at least one capacitively coupled voltage sensor configured to convey an electrical signal to an RF measuring device that measures said RF voltage.