Charged particle beam system and overlay misalignment measurement method

A charged particle beam system comprising:

• a charged particle beam irradiation unit irradiating a sample with a charged particle beam;
• a detector detecting a secondary electron signal or a backscattered electron signal from the sample;
• and
• a computer system controlling the charged particle beam irradiation unit and measuring the amount of overlay misalignment in the sample, wherein
• the computer system includes
• an image generation unit generating an image based on a signal of the detector,
• a matching processing unit specifying a position of an overlay measurement pattern by matching processing in relation to a template image in the image generated by the image generation unit,
• a line profile generation unit generating a first line profile regarding the secondary electron signal and generating a second line profile regarding the backscattered electron signal by selectively scanning a portion of the overlay measurement pattern at the position specified by the matching processing unit, and
• an overlay misalignment measurement unit specifying a position of a first pattern in the overlay measurement pattern from the first line profile, specifying a position of a second pattern in the overlay measurement pattern from the second line profile, and measuring the overlay misalignment in the sample based on the position of the first pattern and the position of the second pattern.