EXPOSURE APPARATUS AND DEVICE FABRICATION METHOD

• US 20080259305A1
• Filed: 04/04/2008
• Published: 10/23/2008
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Goto, Yoshio
• Granted Patent: US 8,064,042 B2
• Time in Patent Office: Days
• US Class Current: 355/67
• CPC Class Codes: G03F 7/70941 Stray fields and charges, e.g. stray light, scattered light, flare, transmission loss
• CPC Class Codes: G03F 7/70958 Optical materials or coatings, e.g. with particular transmittance, reflectance or anti-reflection properties

Abstract

The present invention provides an exposure apparatus comprising an illumination optical system configured to illuminate a reticle with a light beam from a light source, and a projection optical system which is configured to project a pattern of the reticle onto a substrate, and has a numerical aperture of not less than 0.7, the projection optical system including an optical member on which an antireflection coating configured to suppress reflection of the light beam is formed and which is arranged closest to the substrate, wherein a reflectance of the antireflection coating with respect to the light beam is minimum at an incident angle of not less than 30°.

Claims

1. An exposure apparatus comprising:

an illumination optical system configured to illuminate a reticle with a light beam from a light source; and

a projection optical system which is configured to project a pattern of the reticle onto a substrate, and has a numerical aperture of not less than 0.7,

said projection optical system including an optical member on which an antireflection coating configured to suppress reflection of the light beam is formed and which is arranged closest to the substrate,

wherein a reflectance of said antireflection coating with respect to the light beam is minimum at an incident angle of not less than 30°

.

2. The apparatus according to claim 1, wherein a reflectance with respect to the light of the antireflection coating is less than 1.5% at an incident angle of 0°

or more and less than 30°

, and is less than 2.0% at an incident angle of 30°

or more and less than 60°

.

3. The apparatus according to claim 1, wherein said antireflection coating includes, in turn from a side of said optical member,

a first layer with a refractive index lower than a refractive index of said optical member,

a second layer with a refractive index higher than the refractive index of said optical member,

a third layer with a refractive index lower than the refractive index of said optical member,

a fourth layer with a refractive index higher than the refractive index of said optical member, and

a fifth layer with a refractive index lower than the refractive index of said optical member.

4. The apparatus according to claim 3, wherein

each of said first layer, said third layer, and said fifth layer includes magnesium fluoride, and

each of said second layer and said fourth layer includes aluminum oxide.

5. The apparatus according to claim 1, wherein said optical member is a parallel plate.

6. The apparatus according to claim 1, further comprising a light-shielding unit which is interposed between said projection optical system and the substrate, and is configured to shield flare light.

13. A device fabrication method comprising steps of:

exposing a substrate using an exposure apparatus according to claim 1; and

performing a development process for the substrate exposed.

7. An exposure apparatus comprising:

an illumination optical system configured to illuminate a reticle with a light beam from a light source; and

a projection optical system which is configured to project a pattern of the reticle onto a substrate, and has a numerical aperture of not less than 0.7,

said projection optical system including an optical member on which an antireflection coating configured to suppress reflection of the light beam is formed and which is arranged closest to the substrate,

wherein a reflectance of said antireflection coating with respect to an S-polarized light component of the light beam is minimum at an incident angle of not less than 30°

.

8. The apparatus according to claim 7, wherein a reflectance with respect to S-polarized light of the antireflection coating is less than 1.5% at an incident angle of 0°

or more and less than 30°

, and is less than 1.0% at an incident angle of 30°

or more and less than 60°

.

14. A device fabrication method comprising steps of:

exposing a substrate using an exposure apparatus according to claim 7; and

performing a development process for the substrate exposed.

9. An exposure apparatus comprising:

a projection optical system which is configured to project a pattern of a reticle onto a substrate, and has a numerical aperture of not less than 0.7; and

a light-shielding unit which is interposed between said projection optical system and the substrate, and is configured to shield flare light,

wherein said projection optical system includes an optical member arranged closest to the substrate, and

wherein said optical member has, as a surface on a side of the reticle, a concave surface with a curvature radius of 1000 mm (inclusive) to 10000 mm (inclusive).

10. The apparatus according to claim 9, wherein said optical member has, as a surface on a side of the substrate, a convex surface with a curvature radius of 1000 mm (inclusive) to 10000 mm (inclusive).

11. The apparatus according to claim 9, further comprising

an illumination optical system configured to illuminate the reticle with a light beam from a light source,

said optical member including an antireflection coating configured to suppress reflection of the light beam,

wherein a reflectance of said antireflection coating with respect to the light beam is minimum at an incident angle which satisfies a numerical aperture of not less than 0.5.

12. The apparatus according to claim 9, wherein said optical member is spaced apart from the substrate by a distance of not less than 5 mm.

15. A device fabrication method comprising steps of:

exposing a substrate using an exposure apparatus according to claim 9; and

performing a development process for the substrate exposed.