US 12,248,248 B2
Electron beam lithography with a bilayer resist
Antonio Mei, Malibu, CA (US); Ivan Milosavljevic, Thousand Oaks, CA (US); and Amanda Simpson, Thousand Oaks, CA (US)
Assigned to The Boeing Company, Chicago, IL (US)
Filed by The Boeing Company, Chicago, IL (US)
Filed on Oct. 25, 2021, as Appl. No. 17/452,198.
Claims priority of provisional application 63/110,284, filed on Nov. 5, 2020.
Prior Publication US 2022/0137510 A1, May 5, 2022
Int. Cl. G03F 7/038 (2006.01); G03F 7/004 (2006.01); G03F 7/075 (2006.01); G03F 7/20 (2006.01); G03F 7/32 (2006.01)
CPC G03F 7/0382 (2013.01) [G03F 7/0041 (2013.01); G03F 7/0757 (2013.01); G03F 7/2004 (2013.01); G03F 7/32 (2013.01)] 24 Claims
OG exemplary drawing
 
24. A method for processing a material stack, the method comprising:
depositing a hydrogen silsesquioxane layer on the material stack;
depositing an aluminum layer on the hydrogen silsesquioxane layer to form a bilayer;
directing an electron beam through a surface of the bilayer to form an exposed portion of the bilayer, wherein an energy spread of the electron beam is controlled by adjusting an η corrected energy point spread function according to an onset exposure dose Dl described by:

OG Complex Work Unit Math
where η is an energy ratio of backscattered and forward scattered electrons, ρ is a local pattern density %, and A sets a baseline dose at half filling where ρ=50%; and
developing the bilayer with tetramethylammonium hydroxide, wherein the tetramethylammonium hydroxide removes the aluminum layer and an unexposed portion of the hydrogen silsesquioxane layer, leaving the exposed portion of the hydrogen silsesquioxane layer on the material stack,
wherein processing of the material stack forms a quantum dot qubit.