Patent ID: 7425714
Filing Date: 2008-09-16
Classification: B82Y,G01R,H01J

Abstract:
1. A measurement method of electron beam current comprising: irradiating two-dimensionally a plurality of electron beams to at least one target area on a surface of an electron beam detector simultaneously with or after electrically disconnecting a charging element and a measurement circuit by a switch provided between said charging element and said measurement circuit; detecting said irradiated electron beams with the electron beam detector having a plurality of electron beam detecting devices two-dimensionally arrayed therein, while shielding with a shield plate an area on the surface of the electron beam detector other than said target area; accumulating electron beam current detected by the electron beam detector in the charging element as an electric charge; connecting the charging element and the measurement circuit by the switch after a predetermined beam irradiation time passes; calculating an amount of the electron beam current based on the electric charge accumulated in said charging element, wherein, in said electron beam detector, a device pitch of said electron beam detecting devices in one direction is set as twice or more of a range of said plurality of electron beams, and the device pitch is set as an integral multiple of a beam pitch of said plurality of electron beams in said direction.