Detector objective for particle beam apparatus
AssigneeSiemens Aktiengesellschaft
InventorsJuergen Frosien, Hans-Peter Feuerbaum
Life of this patent
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Abstract
A detector objective forms a component of an electron-optical column of a scanning electron microscope, the detector objective being composed of an asymmetrical magnetic lens, an electrostatic immersion lens generating a substantially rotationally symmetrical field, and an annular detector disposed immediately above the magnetic lens body. An electrode of the electrostatic immersion lens is formed as a truncated cone and is arranged in insulated fashion in an upper pole piece of the magnetic lens. The lower pole piece forms the second electrode of the immersion lens. The first and second electrodes are charged with potentials that establish an electrical field for decelerating the primary electrons, the electrical field overlying the focusing magnetic field.
Claims22
A detector objective for a particle beam apparatus, comprising:
- a magnetic lens for focusing a particle beam to a specimen;
- a detector arranged above a pole piece gap of said magnetic lens for detecting secondary particles triggered on the specimen;
- an electrostatic immersion lens overlying said magnetic lens said immersion lens having an upper electrode and a lower electrode;
- means for establishing a first potential at said upper electrode;
- means for establishing a second potential at said lower electrode to form an electrical field in said immersion lens, said first and second potentials being selected so that particles in said electrical field of said immersion lens are slowed down from a first energy to a second lower energy.
A detector objective for a particle beam apparatus, comprising:
- a magnetic lens defining a pole piece gap and having an axis of symmetry, said magnetic lens generating a substantially rotationally symmetrical magnetic field;
- an electrostatic immersion lens for generating a substantially rotationally symmetrical electrical field and including first and second electrodes lying at mutually different potentials, said electrostatic immersion lens being disposed within said magnetic lens symmetrically relative to said axis of symmetry;
- and a detector disposed above said pole piece gap of said magnetic lens symmetrically relative to said axis of symmetry, said detector documenting secondary particles triggered by a primary particle beam directed toward a specimen,
- said first electrode of said electrostatic immersion lens being formed as a truncated cone having a hollow cylindrical projection at one end.
Dependencies are inferred from the claim text.