Ion throughput pump and method

Patent metadata

Field	Value
Publication number	US-10455683-B2
Application number	US-201615169697-A
Country	US
Kind code	B2
Filing date	May 31, 2016
Priority date	May 31, 2016
Publication date	Oct 22, 2019
Grant date	Oct 22, 2019

Abstract

An ion throughput pump (ITP) includes a pump inlet configured to communicate with a vacuum chamber; an ionization source fluidly communicating with the vacuum chamber via the pump inlet and configured for ionizing gas species received from the vacuum chamber; a pump outlet; ion optics configured for accelerating ions produced by the ionization source toward the pump outlet; and a roughing pump stage configured for receiving the ions from the ionization source, producing neutral species from the ions, and pumping the neutral species through the pump outlet.

First claim

What is claimed is:

1. An ion throughput pump (ITP), comprising:
a pump inlet configured to communicate with a vacuum chamber;
an ionization source downstream from the pump inlet and the vacuum chamber, the ionization source configured for ionizing gas species received from the vacuum chamber, wherein the pump inlet defines a path for the gas species to enter the ionization source from the vacuum chamber, and wherein the ionization source comprises a magnet assembly;
a pump outlet;
ion optics arranged generally along a longitudinal axis of the ITP, and configured for accelerating ions produced by the ionization source toward the pump outlet; and
a roughing pump stage spaced from the pump inlet along the longitudinal axis, the roughing pump stage configured for receiving the ions from the ionization source, producing neutral species from the ions, and pumping the neutral species through the pump outlet, wherein:
the ionization source defines an ionization region between the pump inlet and the roughing pump stage;
the ion optics are configured for generating an electric field through the ionization region oriented along the longitudinal axis; and
the magnet assembly is configured to generate a magnetic field that in the ionization region is predominantly oriented in a radial direction orthogonal to the longitudinal axis, such that the ionization source generates a Hall-effect plasma in the ionization region.

2. The ITP of claim 1 , comprising an inlet electrode having a configuration selected from the group consisting of:
the inlet electrode is positioned at or near the pump inlet;
the inlet electrode is positioned at or near the pump inlet, and comprises a plurality of openings formed therethrough;
the inlet electrode is positioned at or near the pump inlet, and comprises a plurality of inlet electrodes axially spaced from each other; and
the inlet electrode is positioned at or near the pump inlet, and comprises a plurality of inlet electrodes axially spaced from each other, wherein each inlet electrode comprises an opening formed therethrough, and the opening of each inlet electrode is offset from the opening of an adjacent one of the plurality of inlet electrodes.

3. The ITP of claim 1 , comprising a gas conductance barrier having a configuration selected from the group consisting of:
the gas conductance barrier is upstream of the roughing pump stage and is configured for establishing an ion path from the ionization source to the roughing pump stage;
the gas conductance barrier is upstream of the roughing pump stage and is configured for establishing an ion path from the ionization source to the roughing pump stage, wherein the gas conductance barrier is an electrode;
the gas conductance barrier is upstream of the roughing pump stage and is configured for establishing an ion path from the ionization source to the roughing pump stage, wherein the gas conductance barrier comprises a plurality of gas conductance barriers axially spaced from each other;
the gas conductance barrier is upstream of the roughing pump stage and is configured for establishing an ion path from the ionization source to the roughing pump stage, wherein the gas conductance barrier comprises a plurality of gas conductance barriers axially spaced from each other, and wherein each gas conductance barrier comprises an opening formed therethrough, and the opening of each gas conductance barrier is offset from the opening of an adjacent one of the plurality of gas conductance barriers; and
the gas conductance barrier is upstream of the roughing pump stage and is configured for establishing an ion path from the ionization source to the roughing pump stage, and further comprising a bypass conduit configured to provide a fluid flow path from the ionization source to the roughing pump stage while bypassing the gas conductance barrier.

4. The ITP of claim 1 , wherein the roughing pump stage has a configuration selected from the group consisting of:
the roughing pump stage comprises a plate positioned such that ions received from the ionization source impinge on the plate and are neutralized thereby; and
the roughing pump stage comprises a plate positioned such that ions received from the ionization source impinge on the plate and are neutralized thereby, wherein the plate is an electrode.

5. The ITP of claim 1 , comprising a roughing pump unit communicating with the roughing pump stage and configured to pump the vacuum chamber down to rough vacuum.

6. The ITP of claim 1 , wherein the ionization source has a configuration selected from the group consisting of:
the ionization source comprises an inner magnet, an outer magnet, and an annular ionization chamber between the inner magnet and the outer magnet;
the ionization source comprises an inner magnet, an outer magnet, and an ionization chamber between the inner magnet and the outer magnet, and the ionization chamber comprises a cylindrical section and an annular section between the pump inlet and the cylindrical section; and
the ionization source comprises an anode, wherein the magnet assembly is between the pump inlet and the anode.

7. The ITP of claim 1 , comprising a supplemental pump selected from the group consisting of:
a non-evaporable getter positioned at an inside surface of the ITP;
a sputter ion pump positioned in an interior of the ITP; and
both of the foregoing.

8. The ITP of claim 1 , wherein:
the ion optics comprise an inlet electrode positioned at or near the pump inlet, and a downstream electrode positioned downstream from the ionization source; and
the downstream electrode is selected from the group consisting of: a gas conductance barrier configured for establishing an ion path from the ionization source to the roughing pump stage; a neutralization element positioned such that ions received from the ionization source impinge on the plate and are neutralized thereby; and both of the foregoing.

9. The ITP of claim 1 , comprising a gas conductance barrier downstream from the ionization source and the magnet assembly and upstream of the roughing pump stage, the gas conductance barrier comprising a plate and an orifice extending through the plate, wherein the gas conductance barrier defines a path for the ions from the ionization source, through the orifice, and to the roughing pump stage, and the path is a low-conductance path for neutral gas species.

10. The ITP of claim 1 , comprising an inlet electrode positioned at or near the pump inlet, the inlet electrode comprising a plurality of openings formed therethrough, wherein the inlet electrode is part of the path for the gas species to enter the ionization source from the vacuum chamber.

11. A method for evacuating a vacuum chamber, the method comprising:
receiving gas species from the vacuum chamber through a pump inlet into an ionization source downstream from the pump inlet and the vacuum chamber, wherein the pump inlet defines a path for the gas species to enter the ionization source from the vacuum chamber, and wherein the ionization source comprises a magnet assembly;
generating an electric field in the ionization source to produce ions from the gas species and accelerate the ions away from the ionization source and toward a pump outlet;
neutralizing the ions to produce neutralized species; and
pumping the neutralized species out from the pump outlet, wherein:
the ionization source defines an ionization region between the pump inlet and the roughing pump stage;
the electric field extends through the ionization region along a longitudinal axis; and
the magnet assembly is configured to generate a magnetic field that in the ionization region is predominantly oriented in a radial

Assignees

• Agilent Technologies Inc

Inventors

• Denning Mark

Classifications

• H01J27/143

  Hall-effect ion sources with closed electron drift · CPC title

• H01J41/12 Primary

  Discharge tubes for evacuating by diffusion of ions, e.g. ion pumps, getter ion pumps · CPC title

• H05H3/02 Primary

  Molecular or atomic-beam generation, e.g. resonant beam generation · CPC title