US 11,749,491 B2
Electron beam writing apparatus and cathode life span prediction method
Satoshi Nakahashi, Yokohama (JP); Nobuo Miyamoto, Yokohama (JP); Takahito Nakayama, Chigasaki (JP); and Shunji Shinkawa, Fujisawa (JP)
Assigned to NUFLARE TECHNOLOGY, INC., Yokohama (JP)
Filed by NUFLARE TECHNOLOGY, INC., Yokohama (JP)
Filed on Jan. 18, 2022, as Appl. No. 17/577,630.
Claims priority of application No. 2021-008117 (JP), filed on Jan. 21, 2021; and application No. 2021-206375 (JP), filed on Dec. 20, 2021.
Prior Publication US 2022/0230834 A1, Jul. 21, 2022
Int. Cl. H01J 37/073 (2006.01); H01J 37/317 (2006.01)
CPC H01J 37/073 (2013.01) [H01J 37/3174 (2013.01); H01J 2237/06333 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An electron beam writing apparatus comprising:
a cathode configured to emit an electron beam;
a condition controller configured to change a condition under which the electron beam is emitted from the cathode in a plurality of ways; and
a prediction unit configured to predict a life span of the cathode based on a temporal change in an amount of fluctuation of a beam characteristic of the electron beam to a change in the condition when the condition is changed.