Corrugated style anode element for ion pumps
AssigneesFEI Company, Varian, Inc.
InventorsJames B. McGinn, Miriam Spagnol
Life of this patent
Estimating the term…
Abstract
An ion pump anode eliminates the intercellular spaces while maintaining an efficient cell shape in which the plasma sheath follows the contour of the cell wall. The cell are preferably quasi-cylindrical and can be manufactured by folding one or more metal strip into a corrugation and welding the strip to create separate cells. By eliminating the intercellular region, which support a high plasma density, the formation of dendrites under such a region is prevented and instabilities caused by those dendrites are eliminated.
Claims21
An ion pump, comprising:
- an anode including multiple anode cells, the anode cells being shaped so that the plasma sheath substantially conforms to the anode walls and the anode cells arranged so as to eliminate intracellular voids;
- a source of a magnetic field for maintaining the plasma within the anode cells;
- two cathodes, one cathode positioned on either side of and spaced apart from the anode;
- and
- a source of an electric field for accelerating particles to sputter the cathode.
An ion pump, comprising:
- an anode including multiple non-rectangular anode cells, the anode cells being arranged to eliminate gaps between the multiple anode cells;
- a source of a magnetic field for maintaining the plasma within the anode cells;
- two cathodes, one cathode positioned on either side of and spaced apart from the anode;
- a source of an electric field between the anode and the cathode for accelerating particles to sputter the cathode.
A method of evacuating a chamber using an ion pump, comprising:
- providing an anode having multiple, non-rectangular anode cells, the cells being packed without interstices in the anode;
- applying a magnetic field for maintaining a plasma in the anode cells;
- providing a cathode including material for sputtering to remove gas from the ion pump environment;
- applying an electric field between the anode and cathode, the electric field accelerating ionized gas particles toward cathode into at least one impact area defined by the at least one anode cell.
A charged particle beam system exhibiting improved stability, comprising:
- a source of charged particles;
- charge particle optics for forming the charged particles into a beam;
- a vacuum system for creating an evacuated environment for the charged particle beam, the vacuum system including an ion pump including an anode having non-rectangular anode cells arranged without gaps between them to form the anode, thereby reducing instabilities of the charged particle beam.
An anode for an ion pump having multiple anode cells, each cell having a shape in which the anode sheath conforms to the anode walls sufficiently to allow efficient transfer of electrons to the anode while minimizing or eliminating the inter-cylindrical cell.
A method of manufacturing an anode for an ion pump, comprising:
- bending one or more metal strips into a wave pattern;
- and
- connecting together sections of the one or more metal strips to form an array of anode cells, the cells having no interstices between them.
Dependencies are inferred from the claim text.