| 摘要 |
A current density distribution characteristic within a beam pattern on a target object can be improved by using a simple-structured electron optical system and a single patterned beam-defining aperture. With an aperture layout modified to be physically fabricable, a current density distribution within the beam pattern is obtained (S5). Then, a current density uniformity is determined by applying preset determination threshold values to the current density distribution within the beam pattern BP obtained as described above (S6), and if it is found not to fall within a tolerance range, tentative inner block portions are set in tentative electron ray passing areas (S7 and S8). Subsequently, by appropriately iterating steps S5 to S8 for the aperture layout modified or renewed by the tentative inner block portions as described above, the tentative electron ray passing areas and the tentative inner block portions, satisfying determination criteria, are decided (S8).
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