| 摘要 |
PURPOSE:To make prompt compensation for variations of electron beam at blanking time by providing a means of generating secondary electron at irradiating time of electron beam to a metal plate making reciprocal motion for controlling passing and intercepting of electron beam. CONSTITUTION:A metal plate 3 provided with a passing hole 31 for electron beam and making reciprocal motion to control the passing and intercepting of electron beam is provided with a secondary-electron generating means 32 such as a projected part for generating the secondary electron by the irradiation of electron beam. In the period of blanking of exposure at intercepting time of electron beam, the secondary electron is projected from the means 32 to a sensor 8, and it is possible to measure the variations of electron beam by a controller 7, also, prompt compensation is made through a first deflection means 4. By such a compensation of variations to be performed within a short time in the blanking period, position-accuracy of electron beam against the target at exposing time can be enhanced. |
