Charged particle beam apparatus, and method of controlling the same

Abstract

Provided is a charged particle beam apparatus, which can emit a stable electron beam, having high brightness and a narrow energy width. The charged particle beam apparatus comprises a field emission electron source, electrodes for applying an electric field to the field emission electron source, and a vacuum exhaust unit for keeping the pressure around the field emission electron source at 1 10−8 Pa or less. The apparatus is so constituted as to use such one of the electron beams emitted as has an electron-beam-center radiation angle of 1×10sr or less, and to use the electric current thereof, the second order differentiation of which is negative or zero with respect to the time, and which reduces at a rate of 10% or less per hour. The charged particle beam apparatus further comprises a heating unit for the field emission electron source, and a detection unit for the electric current of the electron beam. The field emission electron source is repeatedly heated to keep the electric current of the electron beam to be emitted, at a predetermined value or higher.