| 摘要 |
There is disclosed a charged particle beam apparatus capable of adjusting the convergence angle of the charged particle probe independent of the current in the probe. The apparatus comprises a charged particle gun producing a charged particle beam, a first condenser lens, a second condenser lens, an objective lens, an aperture, and an auxiliary condenser lens. The first condenser lens, the second condenser lens, and the objective lens which are arranged in this order act to sharply focus the beam to form an charged particle probe impinging on a specimen. The aperture is installed between the second condenser lens and the objective lens. The auxiliary lens is located between the objective lens and the aperture to control the convergence angle of the probe. The passage of the charged particle beam which extends from the aperture to the specimen is wide enough to prevent the current in the charged particle probe striking the specimen from varying if the strength of the auxiliary lens and the strength of the objective lens are varied.
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