| 摘要 |
PURPOSE:To reduce one stage of lens of electro-optical system and obtain a transformable type electron beam drawing apparatus having excellent stability and operability by making it possible to change, from outside of vacuum system, the distance between the Wehnelt electrode and anode of an electron gun having LaB6 having the flat end point in the axial orientation of <310> or <100> or a large radius of curvature. CONSTITUTION:A concaved area of a knob 7 is engaged in such a way that it can move smoothly with four supporting poles 10 and a convexed area 11 being fixed to the mirrors 6, 6'. A knob 8 is rotated from the clearance between poles 10. Since the concaved area of knob 8 and the convexed area of pole 10 fixed between the mirrors 6, 6' are matched each other, the knob 8 rotates but does not move upward and downward. Accordingly, the anode 3 connected to the flexible bellows 5, 5' moves upward and downward, owing to a screw 9 of knob 8 and a screw 7 of anode 3. As a result, the distance between Wehnelt electrode 2 and the anode 3 changes. When this distance Hwa changes, an electron radiation half-angle alphag also changes. When alphag is changed, intensity distribution changes and thereby a beam current pasing the first forming aperture 13 changes. |
