Charged particle beam apparatus, method of adjusting astigmatism using same and method of manufacturing device using same

A method of observing and estimating, in a charged particle beam apparatus, a sample by irradiating the sample with a charged particle beam to detect secondary charged particles such as electrons emitted from the sample, reflected electrons and backscattered electrons, in which said apparatus having an electro optical system which includes astigmatism adjusting means having a multipole for adjusting astigmatism of the charged particle beam, comprising:

• the step of obtaining a correction voltage which maximizes a value for adjusting focus obtained from an image of a pattern formed on said sample to adjust astigmatism of the charged particle beam,
• said method further comprising the steps of:
• (a) obtaining a first pattern image including lines formed longitudinally and transversely on the sample;
• (b) adjusting said electro optical system to obtain a fist auxiliary voltage when the visibility of the longitudinal and transversal lines of the image becomes maximum;
• (c) applying the first auxiliary voltage to said multipole to adjust a cross section of the electron beam;
• (d) adjusting said electro optical system while maintaining the first auxiliary voltage when the longitudinal line can be seen clearly to obtain a second auxiliary voltage when the visibility of the transverse line in the image becomes maximum;
• (e) applying the second auxiliary voltage to said multipole to adjust the cross section of the electron beam so that a difference between the visibilities of the longitudinal line and the transverse line becomes minimum;
• and
• (f) sequentially applying the steps (a)-(e) to patterns having narrower lines than the first pattern.

A charged particle beam apparatus, comprising:

• means for directing a primary charged particle beam to a sample for irradiation;
• means for guiding, to a detector, secondary charged particles having information about a surface of the sample and obtained by the irradiation of the primary charged particle beam directed to the sample;
• means for combining the secondary charged particles guided to the detector as an image,
• said apparatus further comprising:
• measuring means for measuring an amount of charge on a surface of the sample;
• and
• charge eliminating means for reducing or eliminating the amount of charge on the surface of the sample on the basis of the amount of charge measured by the measurement means.