Projection optical system, exposure apparatus, and device manufacturing method

• US 20060017905A1
• Filed: 08/09/2005
• Published: 01/26/2006
• Est. Priority Date: 11/08/2002
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Suzuki, Masayuki
• Granted Patent: US 7,119,880 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: G02B 17/0657 off-axis or unobscured systems in which all of the mirrors share a common axis of rotational symmetry
• CPC Class Codes: G03F 7/70233 Optical aspects of catoptric systems, i.e. comprising only reflective elements, e.g. extreme ultraviolet [EUV] projection systems

Abstract

A projection optical system for performing reduction projection of a pattern of a reticle onto a projection plane. The system includes a first mirror having a concave reflective surface, a second mirror having a reflective surface, a third mirror having a convex reflective surface, a fourth mirror having a concave reflective surface, a fifth mirror having a convex reflective surface, and a sixth mirror having a concave reflective surface. The reflective surface of the fourth mirror has a curvature radius of not less than 400 mm and not more than 800 mm in absolute value. The reflective surface of the sixth mirror has a curvature radius of not less than 400 mm and not more than 600 mm in absolute value, and the reflective surfaces of the first, second, third, fourth, fifth and sixth mirrors have curvatures of not more than 1500 mm in absolute value, respectively.

Claims

1-20. -20. (canceled)

21. A projection optical system for performing reduction projection of a pattern of a reticle onto a projection plane, said system comprising:

a first mirror having a concave reflective surface;

a second mirror having a reflective surface;

a third mirror having a convex reflective surface;

a fourth mirror having a concave reflective surface;

a fifth mirror having a convex reflective surface; and

a sixth mirror having a concave reflective surface,

wherein said first, second, third, fourth, fifth and sixth mirrors are disposed in the order named from the reticle,

the reflective surface of said fourth mirror has a curvature radius of not less than 400 mm and not more than 800 mm in absolute value,

the reflective surface of said sixth mirror has a curvature radius of not less than 400 mm and not more than 600 mm in absolute value, and

the reflective surfaces of said first, second, third, fourth, fifth and sixth mirrors have curvatures of not more than 1500 mm in absolute value, respectively.

22. An exposure apparatus comprising:

an illumination optical system for illuminating a pattern with light from a light source; and

a projection optical system, as defined in claim 21, for directing light from the pattern to a member to be exposed which is disposed substantially at the projection plane.

23. A device manufacturing method comprising:

a step of exposing the member to be exposed using the apparatus as defined in claim 22;

and

developing the member having been exposed in said exposing step.

24. A projection optical system for performing reduction projection of a pattern of a reticle onto a projection plane, said system comprising:

a first mirror having a concave reflective surface;

a second mirror having a reflective surface;

a third mirror having a convex reflective surface;

a fourth mirror having a concave reflective surface;

a fifth mirror having a convex reflective surface; and

a sixth mirror having a concave reflective surface,

wherein said first, second, third, fourth, fifth and sixth mirrors are disposed in the order named from the reticle, and

wherein the reflective surface of said fourth mirror has a curvature radius not less than 400 mm and not more than 800 mm in absolute value.

25. A projection optical system according to claim 24, wherein the reflective surface of said sixth mirror has a curvature radius not less than 400 mm and not more than 600 mm in absolute value.

26. A projection optical system according to claim 24, wherein the reflective surfaces of said first, second, third, fourth, fifth and sixth mirrors have curvatures not more than 1500 mm in absolute value, respectively.

27. An exposure apparatus comprising:

an illumination optical system for illuminating a pattern with light from a light source; and

a projection optical system, as defined in claim 24, for directing light from the pattern to a member to be exposed, which is disposed substantially at the projection plane.

28. A device manufacturing method comprising:

a step of exposing the member to be exposed using the apparatus as defined in claim 27;

and

developing the member having been exposed in said exposing step.

29. A projection optical system for performing reduction projection of a pattern of a reticle onto a projection plane, said system comprising:

a first mirror having a concave reflective surface;

a second mirror having a convex reflective surface;

a third mirror having a convex reflective surface;

a fourth mirror having a concave reflective surface;

a fifth mirror having a convex reflective surface; and

a sixth mirror having a concave reflective surface,

wherein said first, second, third, fourth, fifth and sixth mirrors are disposed in the order named from the reticle, and

the reflective surface of said sixth mirror has a curvature radius of not less than 400 mm and not more than 600 mm in absolute value.

30. A projection optical system according to claim 29, wherein the reflective surfaces of said first, second, third, fourth, fifth and sixth mirrors have curvatures not more than 1500 mm in absolute value, respectively.

31. An exposure apparatus comprising:

an illumination optical system for illuminating a pattern with light from a light source; and

a projection optical system, as defined in claim 29, for directing light from the pattern to a member to be exposed, which is disposed substantially at the projection plane.

32. A device manufacturing method comprising:

a step of exposing the member to be exposed using the apparatus as defined in claim 31;

and

developing the member having been exposed in said exposing step.