US 7,479,634 B2
	Electron beam apparatus and device manufacturing method using the same
Mamoru Nakasuji, Yokohama (Japan); Takao Kato, Shibuya-ku (Japan); Kenji Watanabe, Fujisawa (Japan); Shoji Yoshikawa, Hachioji (Japan); Tohru Satake, Chigasaki (Japan); and Nobuharu Noji, Zushi (Japan)
Assigned to Ebara Corporation, Tokyo (Japan)
Filed on Mar. 06, 2007, as Appl. No. 11/714,130.
Application 11/714130 is a division of application No. 11/262844, filed on Nov. 01, 2005, granted, now 7,205,540.
Application 11/262844 is a division of application No. 10/234152, filed on Sep. 05, 2002, granted, now 6,998,611.
Claims priority of application No. 2001-269880 (JP), filed on Sep. 06, 2001; application No. 2001-273078 (JP), filed on Sep. 10, 2001; and application No. 2001-368960 (JP), filed on Dec. 03, 2001.
Prior Publication US 2007/0158565 A1, Jul. 12, 2007
This patent is subject to a terminal disclaimer.
Int. Cl. G21K 7/00 (2006.01); G21G 4/00 (2006.01); G01N 23/00 (2006.01)

U.S. Cl. 250—310  [250/311; 250/492.3]

7 Claims

1. An electron beam apparatus having an electro-optical column for illuminating a sample by an electron beam emitted from a thermal electron emitting cathode to detect any one of a secondary electron, a reflected electron and an absorbed electron, wherein a signal/noise ratio or an amount of noise in detecting means is estimated when the sample is illuminated by the electron beam while electric power for heating the cathode is changed to determine a value of the electric power for heating the cathode.