Patent ID: 8101911

Claim:
A charged particle beam device for scanning a charged particle beam over a specimen, the charged particle beam device comprising: a charged particle gun alignment assembly for emitting the charged particle beam along an optical axis of the charged particle beam device, the charged particle gun alignment assembly being configured to compensate for misalignment of the charged particle beam and comprising: a charged particle source having an emitter with a virtual source defining a virtual source plane substantially perpendicular to the optical axis; a condenser lens for imaging the virtual source; a final beam limiting aperture adapted for shaping the charged particle beam; and a double stage deflection assembly positioned between the condenser lens and the final beam limiting aperture, wherein the working distance of the condenser lens is 15 mm or less, wherein not more than 10 percent of the fields of the double stage deflection assembly overlap with the field of the condenser lens; an objective lens for focusing the charged particle beam on the specimen, which can be placed on a specimen location, the objective lens being disposed on a first side of the specimen location; and a detector for detecting secondary particles being disposed on the first side of the specimen location.