Inspection system, inspection method, and process management method
View Patent ↗An inspection apparatus comprising an electron emitting unit for sequentially emitting an electron beam in the direction of an inspection area of a sample; a deceleration unit for drawing back the electron beam in the vicinity of the inspection area; an imaging unit for forming images of the drawing back electron beam on multiple different image forming conditions; an image detecting unit for capturing the electron beam that formed an image corresponding to each image forming condition; and an image processing unit for comparing the images on different image forming conditions with one another to detect a defect in the inspection area.
1. An inspection apparatus comprising:
a sample stage that mounts a sample to be inspected;
an electron optical system which directs electrons to the sample;
a power supply capable of applying a voltage to the sample stage thereby to draw back the electron beam incident on the sample;
an imaging optical system that detects images of the drawn back electron beam with a plurality of image forming conditions; and
an image processing unit that calculates a difference image of images obtained with the plurality of image forming conditions;
wherein the sample is inspected based on the difference image.
2. An inspection apparatus according to claim 1 ,
wherein the imaging optical system includes a plurality of detecting planes of the drawn back electron beam.
3. An inspection apparatus according to claim 1 , further comprising:
a database that stores the difference image.
4. An inspection apparatus according to claim 1 ,
wherein the difference image is calculated as a two-dimensional brightness map.
5. An inspection apparatus according to claim 1 ,
wherein images with the plurality of image forming conditions are obtained by detecting the drawn back electron beam with different focusing conditions.
6. An inspection apparatus according to claim 5 ,
wherein the imaging optical system includes a variable-focus lens composed of electrostatic lenses.