Charged particle beam apparatus

A charged particle beam apparatus comprising:

• a charged particle beam optical system that irradiates a sample mounted on a sample stage with a charged particle beam;
• a detector that detects a signal generated from the sample;
• a charged particle beam imaging device that acquires an observation image from the signal detected by the detector;
• an optical imaging device that captures an optical image of the sample;
• a stage that rotatably holds the sample stage;
• a stage control device that controls the stage;
• an image composition unit that combines a plurality of the optical images to generate a composite image;
• an image context control unit that controls context of the plurality of optical images, such that a frontmost-side optical image among the plurality of the optical images is displayed in its entirety, but rearer-side optical images other than the frontmost-side optical image are partially shielded by the frontmost-side optical image;
• a display unit that displays the composite image;
• a light source for illuminating a sample chamber;
• and
• a light source control device for controlling the light source, wherein
• the optical imaging device illuminates the sample chamber with the light source to capture the optical image during executing an operation of evacuation of the sample chamber,
• when an observation position observed by the charged particle beam imaging device satisfies a predetermined condition, the optical imaging device captures an image of the sample at the observation position, and
• the image composition unit re-generates the composite image by using the captured image.