Patent ID: 7872755
Filing Date: 2011-01-18
Classification: G01N,G02B,G03H,H01J

Abstract:
1. A charged particle beam apparatus comprising: a source of a charged particle beam such as an electron or an ion; a condenser optical system for irradiating a specimen with the charged particle beam emitted from the source; a specimen holder for holding the specimen irradiated with the charged particle beam; an imaging lens system for imaging the specimen; a device for observing or recording the specimen image; an objective lens system formed by one or plurality of lenses capable of controlling focal lengths independently in the imaging lens system positioned on the downstream side on the traveling direction of the charged particle beam from the specimen position on an optical axis of the charged particle beam; an upper-stage biprism located in a plane orthogonal to the optical axis at a position of an image plane of the specimen determined by the objective lens system on the downstream side of the objective lens system; and a lower-stage biprism located in a plane in parallel with the plane where the upper-stage biprism is placed on the downstream side of the upper-stage biprism through one or more lenses in the imaging lens system, both the biprisms being capable of moving of their positions and rotating of their electrodes independently, wherein voltages can be applied to the upper-stage biprism and the lower-stage biprism independently to deflect the charged particle beam in an arbitrary direction, and wherein in a case that an azimuth angle between the upper-stage biprism and the lower-stage biprism is Φ, and an azimuth angle between the upper-stage biprism and interference fringes is θ, the charged particle beam is deflected in condition that the azimuth angle Φ is not zero for controlling the azimuth angle θ.