Sample observation method, sample preparation method, and charged particle beam apparatus

A charged particle beam apparatus, comprising:

• a charged particle beam column configured to irradiate the observation surface of a sample with a charged particle beam;
• a sample stage configured to hold the sample;
• a sample stage driving portion configured to tilt the sample stage about a tilt axis of the sample stage;
• a charged particle detector configured to detect charged particles generated from the observation surface by irradiation of the charged particle beam;
• an image forming portion configured to form charged particle images of the observation surface at a plurality of tilt angles based on detection signals of the charged particle detector;
• and
• a tilt angle calculating portion configured to calculate a tilt angle at which an area of the observation surface in the charged particle image becomes the largest by comparing the area of the observation surface in the charged particle images.

A sample observation method for observing an observation surface of a sample by irradiation of a charged particle beam, the method comprising:

• providing a sample stage holding the sample and configured to be tilted to a plurality of tilt angles to change an incident angle of the charged particle beam to the sample;
• acquiring a charged particle image of the observation surface of the sample at each of the plurality of tilt angles by irradiating the observation surface of the sample with the charged particle beam;
• calculating as an optimum tilt angle a tilt angle of the sample stage at which an area of the observation surface in the acquired charged particle image becomes the largest by comparing the area of the observation surface in the acquired charged particle mages;
• and
• irradiating the observation surface of the sample with the charged particle beam while the sample stage is tilted to the optimum tilt angle to observe the observation surface of the sample.