Patent ID: 6452175
Filing Date: 2002-09-17
Classification: H01J

Abstract:
A column for directing a beam of charged particles onto a specimen surface under an oblique beam landing angle, the column comprising:a particle source for providing the beam of charged particles propagating along an optical axis; an objective lens for focussing the beam of charged particles onto the specimen surface; a pre-lens deflection unit arranged between the particle source and the objective lens; the pre-lens deflection unit deflecting the beam of charged particles away from the optical axis on such a path that the objective lens and the pre-lens deflection unit direct the beam of charged particles towards the optical axis to hit the specimen surface in a first direction; an in-lens deflection unit arranged in the vicinity of the objective lens such that fields of the in-lens deflection unit and the objective lens overlap; the in-lens deflection unit redirecting the deflected beam of charged particles on such a path that the objective lens and the in-lens deflection unit redirect the beam of charged particles towards the optical axis to hit the specimen surface under said oblique beam landing angle in a second direction substantially opposite to said first direction.