| 摘要 |
<p>PURPOSE:To obtain a wide molding beam with high current density and brightness and with smooth current density distribution by using a high brightness LaB6 as the emitter of a Pierce type electron gun with a wide emitter area and obtaining an LSI pattern forming beam by the division of a Wehnelt electrode. CONSTITUTION:A cathode 5 uses a high emission and brightness LaB6 single crystal. The emitter surface is provided with (100) or (110) as accurately as possible and for example, a thermoelectron is radiated by heating it at a high vacuum of 10<-8>Torr. Besides, a Pierce type electrode 6 is mechanically divided into a number of electrodes, for example, four electrodes 6-1 to 6-4, each of which is separated electrically. In order to operate these components, the voltage in the vicinity of cathode potential is applied to 6-1 to 6-4 independently and the field distribution near the tip of a cathode 5 is controlled. As a result, a wide molding beam with high current density and brightness and with smooth current density distribution can be obtained on the surface vertical to an optical axis.</p> |
