Automatic astigmatism compensation and focussing in scanning electron microscope

Abstract

Abstract PURPOSE:To simultaneously and automatically perform astigmatism compensation and focussing by scanning samples under three conditions in which one value of three parameters is different, truncating the maximum condition of the measured value to be obtained, and repeatedly scanning them under new conditions. CONSTITUTION:A computer arbitrarily selects points P1-P3 on plane I1, I2 subsequently supplies current to an astigmatism compensation coil by a combination of I11, I21, I12, I22, I13, and I23, respectively, and read to store the signals from measured circuits. Then the computer compares these signal values and classify them into three: high, intermediate, and low. Firstly, it starts with completely arbitrary three points, truncates the lowest P1, detects one new trial point, forms the three points including the new trial point, also truncates the lowest point, and detects the other new trial point. By repeating this, convergence is slowly enabled to Zenith V0 and astigmatism compensation and focussing are simultaneously enabled.

Inventors

• 👤 Fumio Kataki
• 👤 Keiichiro Higuchi

Bibliographic Details