Filter for material supply apparatus of an extreme ultraviolet light source

Patent metadata

Field	Value
Publication number	US-9029813-B2
Application number	US-201113112784-A
Country	US
Kind code	B2
Filing date	May 20, 2011
Priority date	May 20, 2011
Publication date	May 12, 2015
Grant date	May 12, 2015

Abstract

A filter is used in a target material supply apparatus and includes a sheet having a first flat surface and a second opposing flat surface, and a plurality of through holes. The first flat surface is in fluid communication with a reservoir that holds a target mixture that includes a target material and non-target particles. The through holes extend from the second flat surface and are fluidly coupled at the second flat surface to an orifice of a nozzle. The sheet has a surface area that is exposed to the target mixture, the exposed surface area being at least a factor of one hundred less than an exposed surface area of a sintered filter having an equivalent transverse extent to that of the sheet.

First claim

What is claimed is:

1. An apparatus for supplying a target material to a target location, the apparatus comprising:
a reservoir comprising a reservoir opening and an outer face, the reservoir configured to receive a target mixture that includes the target material and non-target particles, the target material comprising a metal that, when converted to plasma, has an emission line in the extreme ultraviolet (EUV) range;
a first filter through which the target mixture is passed, the first filter comprising a surface area that is exposed to the target mixture;
a second filter through which the target mixture is passed, the second filter comprising a first surface and a second opposing surface;
a supply system comprising a nozzle, the nozzle comprising an orifice that is fluidly coupled to the second surface of the second filter, the supply system configured to receive a filtered target mixture that includes target material that has passed through the first and second filters and configured to supply the filtered target mixture to the target location by passing the filtered target mixture through the orifice; and
a holder that houses the supply system, the holder comprising a face, wherein
the second filter is hermetically sealed to the outer face of the reservoir and hermetically sealed to the face of the holder,
the second filter includes a set of through holes between the first surface and the second surface, the through holes having a longitudinal axis, at least a portion of the through holes having a uniform cross-sectional width along the longitudinal axis, and
the second filter has a surface area that is exposed to the filtered target mixture, the surface area of the second filter that is exposed to the filtered target mixture being less than the surface area of the first filter that is exposed to the target mixture.

2. The apparatus of claim 1 , wherein the second filter receives the target mixture that has passed through the first filter.

3. The apparatus of claim 1 , wherein the through holes of the set of through holes have uniformly-sized cross-sectional widths.

4. The apparatus of claim 3 , wherein the second filter includes a second set of uniformly-sized through holes that extend from the first surface to the second surface, at least some of the through holes in the second set of through holes having a transverse size that is different from a transverse size of the uniformly-sized through holes of the set of through holes.

5. The apparatus of claim 1 , wherein the first filter includes a set of through holes.

6. The apparatus of claim 5 , wherein the cross-sectional widths of the through holes of the first filter set are different from the cross-sectional widths of the through holes of a second filter set.

7. The apparatus of claim 1 , wherein the second filter has a thickness along the longitudinal axis that is large enough to withstand a pressure differential across the second filter.

8. The apparatus of claim 1 , wherein each hole in the set of through holes of the second filter has a cross-sectional width that is less than 10 μm.

9. The apparatus of claim 1 , wherein:
the cross-sectional width of each hole in the set of through holes of the second filter is less than a cross-sectional width of the orifice of the nozzle of the supply system.

10. The apparatus of claim 1 , wherein at least one of the first and second filters is made at least in part of tungsten, titanium, molybdenum, nickel, tantalum, or other metal, quartz, glass, or ceramic material.

11. The apparatus of claim 1 , wherein the through holes of the set in the second filter are sized to block at least some of the non-target particles.

12. The apparatus of claim 1 , wherein the target material is in a fluid state.

13. The apparatus of claim 1 , wherein the second filter is a non-sintered and non-mesh filter.

14. The apparatus of claim 1 , wherein:
the first filter is made of a first material; and
the second filter is made of a second material that is different from the first material;
the apparatus further comprising a radiation source that supplies radiation to the target location to thereby strike the target mixture.

15. An apparatus comprising: a reservoir comprising a reservoir opening, the reservoir configured to receive a target mixture that includes the target material and non-target particles, the target material comprising a metal that, when converted to plasma, has an emission line in the extreme ultraviolet (EUV) range; a first filter through which the target mixture is passed, the first filter comprising a surface area that is exposed to the target mixture; a second filter through which the target mixture is passed, the second filter comprising a first surface and a second opposing surface; and a supply system comprising an orifice that is fluidly coupled to the second surface of the second filter, the supply system configured to receive a filtered target mixture that includes a target material that has passed through the first and second filters and configured to supply the filtered target mixture to the target location by passing the filtered target mixture through the orifice, wherein the second filter is hermetically sealed to an outer face of the reservoir and to a face of a holder that houses the supply system, the second filter has a surface area that is exposed to the filtered target mixture, the surface area of the second filter that is exposed to the filtered target mixture being less than the surface area of the first filter that is exposed to the target mixture, the second filter comprises a plurality of groups of through holes, the through holes extending from the second surface toward the first surface along a longitudinal axis, at least a portion of the through holes having a uniform cross-sectional width along the longitudinal axis, a first end of the through holes in the second filter face a first end of the reservoir, and are fluidly coupled at a second end to the orifice; the second filter comprises a plurality of openings, each opening being between the reservoir opening and a particular group of through holes such that the opening fluidly couples the reservoir opening to the particular group of through holes, and each through hole in the particular group of through holes has a cross-sectional width that is smaller than the cross-sectional width of the opening to which the particular group of through holes is fluidly coupled, the through holes sized to remove at least some of the non-target particles from the target mixture.

16. The apparatus of claim 15 , wherein each of the through holes in any of the groups of through holes has a uniform cross-sectional width along the longitudinal axis.

17. The apparatus of claim 15 , wherein the through holes are a capillary array.

18. The apparatus of claim 15 , wherein each opening is between a first surface of the second filter that is hermetically sealed to the reservoir and a particular group of through holes.

19. The apparatus of claim 15 , wherein the plurality of through holes are defined between a second surface that faces a nozzle and the plurality of openings.

20. The apparatus of claim 1 , wherein:
the second filter comprises a sheet, and the first surface comprises a flat surface and the second surface comprises a flat surface; and
the through holes of the set of through holes in the second filter extend from the second flat surface and are fluidly coupled at the second flat surface to the orifice.

21. The apparatus of claim 1 , whe

Assignees

• Fomenkov Igor V
• Partlo William N
• Vaschenko Georgiy O
• Oldham William
• Asml Netherlands Bv

Inventors

• Fomenkov Igor V
• Partlo William N
• Vaschenko Georgiy O
• Oldham William

Classifications

• H10P76/00 Primary

  Manufacture or treatment of masks on semiconductor bodies, e.g. by lithography or photolithography · CPC title

• H05G2/002

  Supply of the plasma generating material · CPC title

• B01D29/56 Primary

  in series connection · CPC title

• B22F3/105 Primary

  by using electric current {other than for infrared radiant energy}, laser radiation or plasma (B22F3/11 takes precedence){; by ultrasonic bonding (B22F3/115 takes precedence)} · CPC title

• H05H1/46

  using applied electromagnetic fields, e.g. high frequency or microwave energy (H05H1/26 takes precedence) · CPC title