US 11,854,775 B2
Methods and apparatus for microwave plasma assisted chemical vapor deposition reactors
Timothy A. Grotjohn, Okemos, MI (US); and Jes Asmussen, East Lansing, MI (US)
Assigned to BOARD OF TRUSTEES OF MICHIGAN STATE UNIVERSITY, East Lansing, MI (US)
Filed by BOARD OF TRUSTEES OF MICHIGAN STATE UNIVERSITY, East Lansing, MI (US)
Filed on Jan. 16, 2020, as Appl. No. 16/744,830.
Application 16/744,830 is a division of application No. 15/463,046, filed on Mar. 20, 2017, granted, now 10,541,118.
Claims priority of provisional application 62/310,938, filed on Mar. 21, 2016.
Prior Publication US 2020/0152433 A1, May 14, 2020
Int. Cl. H01J 37/32 (2006.01); C23C 16/511 (2006.01); C23C 16/27 (2006.01); C23C 16/52 (2006.01)
CPC H01J 37/3299 (2013.01) [H01J 37/32311 (2013.01); H01J 37/32926 (2013.01); H01J 37/32935 (2013.01); C23C 16/274 (2013.01); C23C 16/511 (2013.01); C23C 16/52 (2013.01); H01J 37/32192 (2013.01); H01J 37/32229 (2013.01); H01J 37/32238 (2013.01); H01J 37/32458 (2013.01); H01J 37/32715 (2013.01); H01J 37/32972 (2013.01)] 21 Claims
OG exemplary drawing
 
1. A microwave plasma assisted reactor system comprising:
a microwave plasma assisted reactor comprising:
(a) a first microwave chamber having an internal volume and comprising an electromagnetic wave source;
(b) a plasma chamber having an outer wall and comprising an optical window forming at least a portion of the outer wall, the plasma chamber extending into the first microwave chamber;
(c) a stage for supporting a substrate, the stage having a reference surface extending into the plasma chamber;
(d) a first electrically conductive, optically transparent region forming at least a portion of the first microwave chamber external boundary; and
(e) a second electrically conductive, optically transparent region forming at least a portion of the first microwave chamber external boundary;
wherein:
the first region and the second region are spatially positioned such that, when a substrate is present on the stage reference surface, light from a coherent light source passing through the first region is in optical communication with the second region by (i) passing through the first region, (ii) passing through the optical window of the plasma chamber, (iii) reflecting off the substrate, (iv) passing through the optical window of the plasma chamber, and (v) passing through the second region; and the light from the coherent light source maintains its coherency when passing through the first region, through the optical window of the plasma chamber, and through the second region;
a coherent light source positioned and adapted to direct the incident beam of coherent light through the first region and into the first microwave chamber internal volume;
a means for detecting a spatial distribution of incident light energy positioned to receive an incident distribution of light that has been reflected and/or scattered from the reflected beam of coherent light by a substrate present on the stage reference surface, when present; and
wherein the microwave plasma assisted reactor system further comprises: (f) a computer comprising a processor and memory coupled to a non-transitory computer readable storage medium encoded with a computer program, the program comprising instructions that, when executed by the processor, cause the computer to control the steerable mirror, the coherent light source, and the means for detecting a spatial distribution of incident light energy during operation of the microwave plasma assisted reactor;
wherein the computer program further comprises instructions that, when executed by the processor, cause the computer to: determine an average local surface angle, a local surface roughness, and a local surface curvature of a substrate during operation of the microwave plasma assisted reactor; and
perform one or more of issuing an alert, halting deposition, and altering deposition conditions in a feedback control loop based on one or more of the average local surface angle, the local surface roughness, and the local surface curvature.