Column for charged particle beam device
AssigneeApplied Materials, Inc.
InventorPavel Adamec
Life of this patent
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Abstract
A charged particle beam column comprises: a particle source; an objective lens; a pre-lens deflection unit for deflecting a beam of charged particles away from the optical axis on such a path that the combined action of the objective lens and the pre-lens deflection unit directs the beam of charged particles towards the optical axis to hit the specimen surface from a first direction; and an in-lens deflection unit arranged in the vicinity of the objective lens for redirecting the deflected beam of charged particles on such a path that the combined action of the objective lens and the in-lens deflection unit redirects the beam of charged particles towards the optical axis to hit the specimen surface under said large beam landing angle from a second direction substantially opposite to said first direction.
Claims30
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.
A method for directing a beam of charged particles onto a specimen surface under a large beam landing angle, the method comprising the steps of:
- a) providing a beam of charged particles propagating along an optical axis;
- b) focussing the beam of charged particles onto the specimen surface;
- c) selecting a beam landing angle;
- d) deflecting the beam of charged particles propagating along the optical axis away from the optical axis,
- whereby the magnitude of the deflection is chosen such that deflecting and focussing the beam directs the beam of charged particles to hit the specimen surface in a first direction,
- the deflection causing a first contribution to the aberration on the specimen surface;
- e) redirecting the deflected beam of charged particles,
- whereby the redirection is chosen such that redirecting and focussing the deflected beam directs the beam of charged particles to hit the specimen surface under said large beam landing angle in a second direction substantially opposite to said first direction;
- the redirection causing a second contribution to the aberration on the specimen surface;
- whereby the deflection in step d) and the redirection in step e) are chosen such that the total aberration on the specimen surface is minimized.
A charged particle column providing oblique beam landing angles on a specimen, comprising:
- a charged particle source providing a beam of charged particles propagating along an optical axis,
- an objective lens creating a focusing field;
- a pre-lens deflection unit positioned between the particle source and the objective lens and, when energized, deflecting the beam of charged particles away from the optical axis in a first direction;
- and
- an in-lens deflection unit;
- wherein, when energized, said in-lens deflection unit creates a deflection field at least partially overlapping the focusing field, and deflecting the particle beam at an inflection point with respect within the focusing field, and wherein the deflection field together with the focusing field deflect the beam in a direction opposite the first direction and, after the beam has crossed the optical axis, redirect the beam so as to hit the specimen substantially at an intersection of the optical axis and the specimen.
Dependencies are inferred from the claim text.