Encapsulation of Electrodes in Solid Media for use in conjunction with Fluid High Voltage Isolation

• US 20110272592A1
• Filed: 06/21/2011
• Published: 11/10/2011
• Est. Priority Date: 12/30/2009
• Status: Active Grant

• Current Assignee: FEI Company (Thermo Fisher Scientific Incorporated)
• Original Assignee: FEI Company (Thermo Fisher Scientific Incorporated)
• Inventors: McGinn, James B., Wells, Andrew B., Kellogg, Sean, Graupera, Anthony, Parker, N. William, Utlaut, Mark W.
• Granted Patent: US 8,642,974 B2
• Time in Patent Office: Days
• US Class Current: 250/396.R
• CPC Class Codes: H01J 2237/002 Cooling arrangements of objects being observed or treated H01J2237/2001
• CPC Class Codes: H01J 2237/061 Construction
• CPC Class Codes: H01J 2237/0817 Microwaves
• CPC Class Codes: H01J 2237/31749 Focused ion beam
• CPC Class Codes: H01J 27/16 using high-frequency excitation, e.g. microwave excitation
• CPC Class Codes: H01J 37/08 Ion sources; Ion guns
• CPC Class Codes: H01J 37/321 the radio frequency energy being inductively coupled to the plasma
• CPC Class Codes: H05H 1/46 using applied electromagnetic fields, e.g. high frequency or microwave energy H05H1/26 takes precedence
• CPC Class Codes: H05H 1/4652 using inductive coupling means, e.g. coils

Abstract

An inductively-coupled plasma source for a focused charged particle beam system includes a conductive shield that provides improved electrical isolation and reduced capacitive RF coupling and a dielectric fluid that insulates and cools the plasma chamber. The conductive shield may be enclosed in a solid dielectric media. The dielectric fluid may be circulated by a pump or not circulated by a pump. A heat tube can be used to cool the dielectric fluid.

Claims

1. A charged particle beam system, comprising:

a plasma source having;

a plasma chamber having a wall composed of a dielectric material, the wall having an interior surface and an exterior surface;

a conductor coiled at least one time around the plasma chamber;

a conductive shield substantially encapsulated in a solid dielectric media, the conductive shield positioned between the plasma chamber and the conductor; and

a source electrode for electrically biasing the plasma to a high voltage; and

one or more focusing lenses for focusing charged particles from the plasma source onto a sample.

2. The charged particle beam system of claim 1 further comprising a sample stage for holding the sample to be processed by a beam from the plasma source.

3. The charged particle beam system of claim 1 further comprising a liquid contacting at least a portion of the solid dielectric media.

4. The charged particle beam system of claim 3 in which a portion of the liquid is positioned between the plasma chamber and the conductor.

5. The charged particle beam system as in claim 3 in which the liquid is not pumped.

6. The charged particle beam system of claim 1 in which the shield includes gaps for passing an induction field to the plasma.

7. The charged particle beam system of claim 1 in which the dielectric media comprises a resin or polymer.

8. The charged particle beam system of claim 1 in which a non-encapsulated portion of the shield is exposed for making electrical contact.

9. A charged particle beam system, comprising:

a plasma source having;

a plasma chamber having a wall composed of a dielectric material, the wall having an interior surface and an exterior surface;

a conductor coiled at least one time around the plasma chamber;

a static liquid surrounding and in thermal contact with at least a portion of the plasma chamber; and

a source electrode for electrically biasing the plasma to a high voltage; and

one or more focusing lenses for focusing charged particles from the plasma source onto a sample.

10. The charged particle beam system of claim 9 in which a portion of the liquid is positioned between the plasma chamber and the conductor.

11. The charged particle beam system of claim 9 in which the liquid has a dielectric constant greater than 5.

12. The charged particle beam system of claim 9 in which the liquid comprises water or a fluorine compound.

13. The charged particle beam system of claim 9 further comprising a conductive shield positioned between the plasma chamber and the conductor, at least a portion of the liquid positioned between the plasma chamber and the conductive shield.

14. The charged particle beam system of claim 13 in which the conductive shield is substantially encapsulated in a solid dielectric media.

15. The charged particle beam system of claim 9 in which the liquid is cooled by a heat pipe.

16. A charged particle beam system, comprising:

a plasma source having;

a plasma chamber having a wall composed of a dielectric material, the wall having an interior surface and an exterior surface;

a conductor coiled at least one time around the plasma chamber;

a liquid in thermal contact with at least a portion of the plasma chamber, a portion of the liquid being positioned between the plasma chamber and the conductor;

a heat pipe cooling device for cooling the fluid; and

a source electrode for electrically biasing the plasma to a high voltage; and

one or more focusing lenses for focusing charged particles from the plasma source onto a sample.

17. The charged particle beam system of claim 16 in further comprising a conductive shield positioned between the plasma chamber and the conductor.

18. The charged particle beam system of claim 17 in which the conductive shield is substantially encapsulated in a solid dielectric media.

19. The charged particle beam system of claim 16 in which the fluid is a static fluid.

20. The charged particle beam system of claim 16 in which the fluid inside of the heat pipe is separate from the fluid in thermal contact with at least a portion of the plasma chamber.