Electrostatic-magnetic lens for particle beam apparatus
AssigneeSiemens Aktiengesellschaft
InventorsJuergen Frosien, Erich Plies
Life of this patent
Estimating the term…
Abstract
An electrostatic-magnetic lens is provided having either a symmetrical or asymmetrical magnetic lens which is overlaid with an electrostatic immersion lens. One electrode of the immersion lens is formed as a hollow cylinder, which is within an upper pole piece of the magnetic lens concentrically relative to the axis of symmetry thereof and extending into the region of the pole piece gap. The lower pole piece of the magnetic lens is preferably at a ground potential and clad with the beam guiding tube for protection against contamination and forming the lower electrode of the electrostatic immersion lens.
Claims16
An electrostatic-magnetic lens for a particle beam apparatus, comprising:
- a magnetic lens having an upper and a lower pole piece;
- an electrostatic immersion lens superimposed on said magnetic lens and comprising:
- a first electrode arranged in a region of said upper pole piece and means for applying a first potential to said first electrode, and
- a second electrode and means for charging said second electrode with a second potential to generate an electrical field in said electrostatic immersion lens so that a particle beam in said electrical field is decelerated from a first energy to a second lower energy. PG,13
An electrostatic-magnetic lens for a particle beam apparatus, comprising:
- a magnetic lens having an upper and a lower pole piece;
- an electrostatic immersion lens superimposed on said magnetic lens and comprising:
- a first electrode arranged in a region of said upper pole piece and means for applying a first potential to said first electrode, and
- a second electrode arranged in a region of said lower pole piece and means for applying a second potential to said second electrode to generate a field in said immersion lens so that a particle beam is decelerated from a first energy to a second lower energy.
An electrostatic-magnetic lens for a particle beam apparatus, comprising:
- a magnetic lens for generating a magnetic flux and including:
- an excitation coil,
- an upper pole piece, and
- a lower pole piece spaced from said upper pole piece by a pole piece gap,
- said magnetic lens being symmetrical about an axis of symmetry;
- an electrostatic immersion lens for generating an electrical retarding field and including:
- a hollow cylindrical electrode disposed within said upper pole piece and symmetrical about said axis of symmetry,
- said lower pole piece forming a second electrode of said immersion lens and connected to a predetermined potential;
- a hollow cylindrical part cladding said lower pole piece;
- and
- a cylindrical insulator disposed between said upper pole piece of said magnetic lens and said cylindrical electrode of said immersion lens.
Dependencies are inferred from the claim text.