| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an ion milling device capable of increasing processing accuracy of a targeted item by decreasing a divergence angle of an ion beam incident on the targeted item.SOLUTION: By allowing electrons from a processing chamber 22 to enter an extraction electrode system 10 of an ion source 2, ion-beam space charge in the extraction electrode 10 is relaxed to suppress divergence of an ion beam 18, thus causing the ion beam 18 to be incident on a targeted item 20. For this purpose, a plasma generator 26 that generates downstream-part plasma 36 is provided in the processing chamber 22, and the potentials Vto Vof first to fourth electrodes 11 to 14 are set so that electrons 38 in the downstream-part plasma 36 can be allowed to enter the extraction electrode system. The downstream-part plasma 36 is generated such that high frequency discharge ionizes inert gas 34 with high frequency electrodes 28 and 29. Vis set to a positive potential. Vis set to a negative potential whose absolute value greater than the potential of the downstream-part plasma 36. Vis set to a positive potential that is lower than the potential of the source plasma and is higher than the potential of the downstream-part plasma 36. Vis set to the ground potential.</p> |
