| 摘要 |
PURPOSE:To enable reducing total drawing time by automatically switching acceleration voltage of electron beam in accordance with the precision of drawing making the acceleration voltage higher for high precision drawing of figures and making it lower for comparatively lower precision drawing. CONSTITUTION:In the case of high precision drawing, each switch is connected as shown by a real line and by a selected power source 5a, e.g., 50kV high acceleration voltage is applied between an acceleration electrode 4 and a control electrode 3 and an electron beam is extremely focused on a material 9. The region where highly precise drawing is required is also drawn precisely. When comparatively low precision is permitted for drawing, an electromagnetic coil 7 and an alignment coil 13 are demagnetized, a computer 19 is switched at S3 and S5 as shown by a dotted line and at S4 and S6, switched as shown by a real line, e.g., such comparatively low acceleration voltage as approx. 25kV is applied and a comparatively great diameter electron beam is irradiated on the material 9, consequently, number of stage 8 shifts can be reduced and high speed drawing becomes possible. |
