Patent ID: 9236218
Filing Date: 2016-01-12
CPC Classification: G01N,G03F,H01J

Claim Text:
1. A defect inspection apparatus comprising: an electron scanning unit configured to scan a surface of a sample with an electron beam; a plurality of detectors arranged around an optical axis of the electron beam and configured to detect electrons emitted from the surface of the sample by scanning with the electron beam; a signal processing unit configured to generate image data of the surface of the sample based on detection signals from the detectors; an analysis unit configured to detect a defect due to irregularities of the surface of the sample based on the image data; a control unit configured to control a scanning speed of the electron beam depending on the type of the sample, wherein the signal processing unit generates a subtracted image obtained by subtracting an image data captured for a first direction from another image captured for a second direction opposite to the first direction with an optical axis of the electron beam in-between, wherein the analysis unit detects the irregularities of the surface of the sample based on a luminance value of the subtracted image, wherein the analysis unit calculates subtraction profiles of a defect portion containing the irregularities and a background portion where the irregularities are not detected respectively in the subtracted image, and wherein the analysis unit finds an integral profile by subtracting a background integral profile obtained by adding the subtraction profile of the background portion from a defect integral profile obtained by adding the subtraction profile of the defect portion.