Patent ID: 8086022
Filing Date: 2011-12-27
Classification: G01N,H01J

Abstract:
1. An inspection system having a scanning electron microscope, comprising: a scan deflector for performing a scan of an electron beam on a sample surface; an objective lens for focusing the electron beam on the sample surface; a secondary electron detector for detecting secondary electrons or backscattered electrons from the sample to generate an analog brightness signal; an AD converter for sampling the analog brightness signal at a predetermined sampling rate; and a digital signal processing circuit for generating an image signal from a sampled signal generated by the AD converter, wherein the digital signal processing circuit generates a digital brightness signal of a frequency smaller than that of the sampling rate by adding contiguous digital values contained in the sampled signal on a predetermined number by predetermined number digital value basis, and divides each digital value of the generated digital brightness signals by a number equal to the number of times of the addition so that the number of bits of the generated digital brightness signal becomes equal to that of digital values of the sampled signal to generate an image signal in which each digital value of the divided digital brightness signal constitutes one pixel data.