US 11,942,306 B1
Atomic layer etching by electron wavefront
Samir John Anz, La Crescenta, CA (US); David Irwin Margolese, Pomona, CA (US); William Andrew Goddard, Pasadena, CA (US); and Stewart Francis Sando, St. Petersburg, FL (US)
Assigned to VELVETCH LLC, Pasadena, CA (US)
Filed by VELVETCH LLC, Pasadena, CA (US)
Filed on Sep. 25, 2023, as Appl. No. 18/474,114.
Application 18/474,114 is a continuation of application No. 18/149,893, filed on Jan. 4, 2023, granted, now 11,869,747.
This patent is subject to a terminal disclaimer.
Int. Cl. H01J 37/32 (2006.01); H01L 21/3065 (2006.01)
CPC H01J 37/32045 (2013.01) [H01J 37/32027 (2013.01); H01L 21/3065 (2013.01); H01J 2237/3341 (2013.01)] 24 Claims
OG exemplary drawing
 
1. A method for atomic layer etching of a substrate, the method comprising:
generating a volume of gaseous plasma including diluent species, reactive species, and electrons of a uniform steady state composition in a positive column of a DC plasma proximate a substrate, thereby developing a floating potential at a surface of the substrate;
adjusting the floating potential to a known reference potential;
forming a corrosion layer on the substrate, the corrosion layer comprising corrosion layer species formed by adsorption of the reactive species to atoms of an atomic layer at the surface of the substrate;
determining a reaction threshold voltage for stimulating electron transitions in the corrosion layer species;
based on the determining, applying a positive pulse voltage to the substrate, the positive pulse voltage comprising a positive high voltage with respect to the floating potential that is equal to the reaction threshold voltage; and
based on the applying, drawing electrons from the volume of gaseous plasma to the surface of the substrate, thereby etching away the atomic layer.