US 12,406,828 B2
Optical system adjustment method for multi charged particle beam apparatus and computer readable recording medium
Hirofumi Morita, Setagaya-ku (JP)
Assigned to NuFlare Technology, Inc., Yokohama (JP)
Filed by NuFlare Technology, Inc., Yokohama (JP)
Filed on Jan. 25, 2023, as Appl. No. 18/159,177.
Claims priority of application No. 2022-021384 (JP), filed on Feb. 15, 2022.
Prior Publication US 2023/0260749 A1, Aug. 17, 2023
Int. Cl. H01J 37/317 (2006.01)
CPC H01J 37/3177 (2013.01) [H01J 2237/0437 (2013.01); H01J 2237/083 (2013.01); H01J 2237/24578 (2013.01); H01J 2237/30488 (2013.01); H01J 2237/31762 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An optical system adjustment method for a multi charged particle beam apparatus that irradiates a substrate placed on a stage with a multi charged particle beam through an illumination optical system including a plurality of components, and an objective lens successively, the optical system adjustment method comprising:
measuring positional deviation amounts of a plurality of individual beams included in the multi charged particle beam at two or more different heights in an optical axis direction of a measurement surface or an imaging position of the multi charged particle beam;
calculating a normalized position difference based on the two or more heights and the positional deviation amounts, the normalized position difference being an illumination system aberration equivalent amount of the illumination optical system; and
adjusting a set value for at least one of the plurality of components using a value of the normalized position difference.