| 摘要 |
PURPOSE:To exceedingly accurately make the dimensional measurement at the arbitrary locations on a sample by actually providing a third electron beam deflector on the front focusing surface of the final stage focusing lens in a focusing lens system and supplying a field view shift signal to the deflector. CONSTITUTION:An electron beam deflector 13 for shifting a field view provided newly is located on the same plane (front focusing plane) as the front focal point Ff of an objective lens. In addition, only the signal from a shift power supply 12 is supplied to the deflector 13. When an electron beam 2 is scanned using this deflector 13, the central beam orbits are as shown by 2a, 2b, and 2c and all central beams passing through the objective lens are parallel to an optical axis. Thus, even when the height of the observation location of the sample is varied, the amount of the field view is not varied at all. As a result, once the relationship between the shift current (or voltage) and the amount of shift is calibrated using a reference sample, the distance (dimension) between the arbitrary two points on the sample can be measured from the shift current value independently of magnification and the height of the sample. |
