Patent ID: 6617592
Filing Date: 2003-09-09
Classification: H01J

Abstract:
A charged particle beam system comprising:a chamber having a space to accommodate a specimen and a first opening to communicate with the space in an upper surface; a table placed, immediately below the first opening, on a bottom surface of the chamber, the table being movable in at least one direction; a laser interferometer set in the chamber, the laser interferometer comprising a laser oscillator placed along the one moving direction of the table, a movable mirror placed on that side surface of the table, which opposes the laser oscillator, a beam splitter placed on a line connecting the laser oscillator and the movable mirror, and a fixed mirror perpendicular to the line connecting the laser oscillator and the movable mirror and fixed, immediately above the beam splitter, on the upper surface of the chamber; an optical lens barrel having a second opening communicating with the first opening of the chamber, and coupled with the chamber so as to match the first opening and the second opening; and a beam gun set on an inner upper surface of the optical lens barrel to irradiate the specimen placed on the table set on the bottom surface of the chamber with a charged particle beam through the first opening and the second opening, wherein at least an upper wall portion from the opening to a fixed portion of the fixed mirror of the chamber is made of an invar alloy.