| 摘要 |
PURPOSE:To realize the ion-beam exposure of high-speed and high precision, by making an ion-source to be an electric field radiation type driven by a constant- current source installing a drawer voltage detecting part to the ion-source and a unipotential lens, and controlling the focusing intensity of the unipotential lens by means of the drawer voltage detecting part output. CONSTITUTION:An electric field type is used for an ion-source 9. Compared with a conventional plasma type, this type has a high radiation current density and a small radiation energy range, so the ion-beam can be a spot with high accuracy. As the electric field radiation type ion-source radiates the ion-beam from a needle-shaped emitter, it can be almost regarded as a complete point ion-source. Therefore, the beam which passes through a shaping stop 10 of quadrangular hole, is reduced in the ingradient of the current density distribution even in the periphery and a microspot-shaping ion-beam which has a sharp current density distribution in the beam peripheral area can be formed. A constant-current source 12 is used to stabilize the beam current density, and also the beam having constant current-density can be formed by controlling the focusing intensity of the unipotential lens 7. |
