Patent ID: 8389935

Claim:
A charged particle beam apparatus that irradiates a primary charged particle beam to a sample and detects secondary charged particles generated due to the irradiation, comprising: an objective lens that focuses the primary charged particle beam on the sample; and means for applying a retarding voltage to the sample, wherein the objective lens includes: an opening through which the charged particle beam passes; a yoke member formed with a hollowed annular member which is disposed around a center axis of the objective lens passing through the opening; a booster magnetic path member disposed in a space between the yoke member and the center axis of the objective lens; and a control magnetic path member disposed in a space between the bottom of the yoke member and the sample; and a magnetic flux concentration on a gap between the booster magnetic path member and the control magnetic path member, and wherein the objective lens is configured to transfer the excited magnetic flux of the yoke member to the booster magnetic path member and the control magnetic path member, and a potential at the control magnetic path member is controlled to be a potential that is equal to or higher than the retarding voltage and that is lower than the potential at the yoke member.