The surface shape measuring method according to the scanning electron microscope

摘要

PURPOSE:To shorten the process time and correctly calculate the normal line direction or inclination by using the relationship between the signals obtained from four detectors or their integral times detectors and differential coefficients of two directions crossing at right angles. CONSTITUTION:A sample is scanned by a focused electron beam, and secondary electrons emitted from the surface of the sample are detected by four detectors 401-404. The secondary electrons emitted from the secondary electron emission point 302 on the sample 301 are emitted in four directions according to the cosine rule. Since the four detectors are applied with the electric field between them and the sample to collect secondary electrons respectively, the secondary electrons emitted toward the first - fourth quadrants are gradually bent by the electric field on their orbits and detected when they reach the first-fourth detectors 401-404. In this case, the relational expression between the signals obtained by the detectors and the differential coefficients of two directions crossing at right angles in the normal line direction of the surface or on the horizontal plane is used to determine the differential coefficients of positions on the sample, the differential coefficients are added or integrated in sequence, and the surface shape of the sample is measured. The process time is thereby shortened, and the normal line direction or inclination can be correctly calculated.