THEORETICAL EVALUATION OF A TOPOGRAPHIC CONTRAST OF SCANNING ELECTRON-MICROSCOPE IMAGES

Topographic contrasts found in a image of the scanning electron microscope are quantitatively discussed. We quantify various contributions separately to the total signal intensity of the image, using a simulation which takes into account electron trajectories in and out of the specimen surface. This analysis indicates that the pattern edge shows higher contrast at lower beam energy if the beam diameter is zero, but on the contrary, the same edge shows higher contrast at higher beam energy if the beam diameter is fairly large. It is also found that the signal from the side wall at the pattern edge gives the major contribution for determining the characteristic shape of the edge contrast for both intensity profiles of secondary and backscattered electron signals.