Faceted EUV optical element

Patent metadata

Field	Value
Publication number	US-10635002-B2
Application number	US-201615374533-A
Country	US
Kind code	B2
Filing date	Dec 9, 2016
Priority date	Dec 18, 2014
Publication date	Apr 28, 2020
Grant date	Apr 28, 2020

Abstract

A reflective EUV optic such as a collector mirror configured as an array of facets that are spaced apart to form respective gaps between adjacent facets. The gaps are used as inlets for gas flow across one of the facets such that flow is introduced parallel to the optic surface. The facets can be made with offsets such that loss of reflective area of the EUV optic can be minimized. The gas facilitates removal of target material from the surface of the facets.

First claim

What is claimed is:

1. A reflective EUV optic comprising:
a first facet comprising a first portion of a reflective surface of the reflective EUV optic; and
a second facet comprising a second portion of the reflective surface of the reflective EUV optic, the first facet being separated from the second facet in a direction parallel to an optical axis of the reflective EUV optic and the first facet overlapping the second facet in a direction substantially tangential to the reflective surface to form a gap between the first facet and the second facet.

2. A reflective EUV optic as claimed in claim 1 wherein the first facet is separated from the second facet in a direction parallel to and the same as the optical axis of the reflective EUV optic.

3. A reflective EUV optic as claimed in claim 1 wherein the first facet is separated from the second facet in a direction parallel and opposed to the optical axis of the reflective EUV optic.

4. A reflective EUV optic as claimed in claim 1 , the reflective EUV optic being substantially rotationally symmetric about a central optical axis, wherein the first facet and the second facet are substantially annular.

5. A reflective EUV optic as claimed in claim 4 wherein the first and second facets together make up substantially the entire reflective surface.

6. A reflective EUV optic as claimed in claim 1 , further comprising a plenum in fluid communication with the gap.

7. A reflective EUV optic as claimed in claim 6 , further comprising a gas supply in fluid communication with the plenum.

8. A reflective EUV optic as claimed in claim 7 , wherein the EUV optic is located within a chamber, and wherein the gas supply in fluid communication with the plenum is at a pressure higher than a pressure in the chamber.

9. A reflective EUV optic having a reflective surface, the reflective surface being comprised of a plurality of facets with adjacent facets being separated by respective gaps wherein at least one facet of the plurality of facets is separated from an adjacent facet in a direction parallel to an optical axis of the EUV optic and overlaps the adjacent facet in a direction substantially tangential to the reflective surface where the facet overlaps the adjacent facet.

10. A reflective EUV optic as claimed in claim 9 , wherein the reflective surface is substantially rotationally symmetric about a central optical axis, and wherein the facets are substantially annular.

11. A reflective EUV optic as claimed in claim 10 , wherein the plurality of annular facets together make up substantially the entire reflective surface.

12. A reflective EUV optic as claimed in claim 9 , further comprising a plenum in fluid communication with the gaps.

13. A reflective EUV optic as claimed in claim 12 , further comprising a gas supply in fluid communication with the plenum.

14. A reflective EUV optic as claimed in claim 13 , wherein the EUV optic is located within a chamber, and wherein the gas supply in fluid communication with the plenum is at a pressure higher than a pressure in the chamber.

15. A reflective EUV optic having a reflective surface, the reflective surface being comprised of a plurality of ring-shaped facets arranged concentrically about an optical axis of the EUV optic, with adjacent facets being separated by respective gaps.

16. A reflective EUV optic as claimed in claim 15 , wherein the plurality of annular ring-shaped facets together make up substantially the entire reflective surface.

17. A reflective EUV optic as claimed in claim 15 , further comprising a plenum in fluid communication with the gaps.

18. A reflective EUV optic as claimed in claim 17 , further comprising a gas supply in fluid communication with the plenum.

19. A reflective EUV optic as claimed in claim 18 , wherein the EUV optic is located within a chamber, and wherein the gas supply in fluid communication with the plenum is at a pressure higher than a pressure in the chamber.

20. A reflective EUV optic having a reflective surface, the reflective surface being comprised of a plurality of facets with adjacent facets being separated by respective gaps wherein at least one facet of the plurality of facets is separated from an adjacent facet in a direction parallel to an optical axis of the EUV optic.

21. A reflective EUV optic having a reflective surface, the reflective surface being comprised of a plurality of facets with adjacent facets being separated by respective gaps wherein at least one facet of the plurality of facets overlaps an adjacent facet in a direction substantially tangential to the reflective surface where the facet overlaps the adjacent facet.

Assignees

• Asml Netherlands Bv

Inventors

• Brandt David C
• Ershov Alexander I
• Fomenkov Igor V

Classifications

• G03F7/70033 Primary

  by plasma extreme ultraviolet [EUV] sources · CPC title

• G03F7/70916

  Pollution mitigation, i.e. mitigating effect of contamination or debris, e.g. foil traps · CPC title

• G21K2201/067

  Construction details · CPC title

• G21K1/062

  Devices having a multilayer structure · CPC title

• G03F7/7015 Primary

  Details of optical elements · CPC title