Polarization-modulating element, illumination optical apparatus, exposure apparatus, and exposure method

Patent metadata

Field	Value
Publication number	US-9429848-B2
Application number	US-28951808-A
Country	US
Kind code	B2
Filing date	Oct 29, 2008
Priority date	Feb 6, 2004
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

There is disclosed a polarization-modulating element for modulating a polarization state of incident light into a predetermined polarization state, the polarization-modulating element being made of an optical material with optical activity and having a circumferentially varying thickness profile.

First claim

What is claimed is:

1. An illumination optical apparatus which illuminates an object having a pattern with illumination light, the illumination optical apparatus comprising:
a polarization-modulating element made of an optical material having optical activity, which is arranged in an optical path of the illumination light and which changes a polarization state of the illumination light incident on the polarization-modulating element into a predetermined polarization state based on the optical activity of the optical material, the polarization-modulating element having a circumferentially varying thickness profile;
an annular ratio changing optical system, arranged in the optical path of the illumination light, that changes an annular ratio of a light intensity distribution formed on an illumination pupil of the illumination optical apparatus; and
an optical integrator arranged in the optical path of the illumination light so that a rear focal plane of the optical integrator is substantially coincident with the illumination pupil,
wherein the polarization-modulating element is arranged between the annular ratio changing optical system and the optical integrator, and
wherein the circumferentially varying thickness profile is formed to change a linearly polarized state of the illumination light having a polarization direction substantially along a single direction into an azimuthal polarized state having a polarization direction substantially along a circumferential direction on the illumination pupil.

2. The illumination optical apparatus according to claim 1 , wherein the polarization-modulating element has a central region having no optical activity, the central region having a radial size that is not less than ⅓ of a radial size of an effective region of the polarization-modulating element, the central region being enclosed by the optical material having optical activity.

3. The illumination optical apparatus according to claim 1 , wherein the polarization-modulating element has a central region and a depolarizer arranged in the central region, the central region being enclosed by the optical material having optical activity.

4. The illumination optical apparatus according to claim 1 , wherein the polarization modulating element has sector-shaped elements which are circumferentially arranged.

5. The illumination optical apparatus according to claim 1 , wherein the illumination optical apparatus satisfies the following conditions:
(10in+Δ A )/10out<0.75;

0.4<(10in+Δ A )/10out,

where 10in: an effective radius of a central region of the polarization-modulating element,
10out: an outside effective radius of the polarization-modulating element, and
ΔA: an increase of an inside radius of a beam passing through the annular ratio changing optical system.

6. An exposure apparatus which exposes a photosensitive substrate with light from a pattern on an object, the exposure apparatus comprising:
a stage which holds the photosensitive substrate;
the illumination optical apparatus according to claim 1 which illuminates the pattern on the object; and
a projection optical system which projects an image of the pattern illuminated with the light onto the photosensitive substrate held by the stage.

7. A device manufacturing method comprising the steps of:
projecting an image of a predetermined pattern onto a photosensitive substrate, using the exposure apparatus according to claim 6 , and
developing the photosensitive substrate.

8. The exposure apparatus according to claim 6 , wherein the photosensitive substrate is exposed with the light from the pattern through liquid disposed below the projection optical system.

9. The exposure apparatus according to claim 6 , wherein the circumferentially varying thickness profile of the polarization-modulating element is formed so that the object is illuminated with the illumination light from the polarization-modulating element via the illumination pupil in a polarization state in which a principal component is S-polarized light.

10. The exposure apparatus according to claim 1 , wherein the polarization-modulating element is arranged so that a crystallographic axis of the optical material having optical activity is substantially coincident with an optical axis of the illumination optical apparatus.

11. The illumination optical apparatus according to claim 1 , wherein circumferentially varying thickness profile is formed so that the object is illuminated with the illumination light from the polarization-modulating element via the illumination pupil in a polarization state in which a principle component is S-polarized light.

12. The illumination optical apparatus according to claim 1 , wherein the polarization-modulating element is arranged so that a crystallographic axis of the optical material having optical activity is substantially coincident with an optical axis of the illumination optical apparatus.

13. An exposure method for exposing a photosensitive substrate with light from a pattern on an object, the exposure method comprising:
holding the photosensitive substrate by a stage;
illuminating the pattern with the light by using the illumination optical apparatus as defined in claim 1 ; and
projecting an image of the pattern illuminated with the light onto the photosensitive substrate held by the stage.

14. The exposure method according to claim 13 , wherein the photosensitive substrate is exposed with the light from the pattern through liquid.

15. The exposure method according to claim 13 , wherein the circumferentially varying thickness profile of the polarization-modulating element is formed so that the object is illuminated with the illumination light from the polarization-modulating element via the illumination pupil in a polarization state in which a principal component is S-polarized light.

16. The exposure method according to claim 13 , wherein the polarization-modulating element is arranged so that a crystallographic axis of the optical material having optical activity is substantially coincident with an optical axis of the illumination optical apparatus.

17. A device manufacturing method comprising the steps of:
projecting an image of a predetermined pattern onto a photosensitive substrate, using the exposure method according to claim 13 , and
developing the photosensitive substrate.

Assignees

• Tanitsu Osamu
• Shigematsu Koji
• Hirota Hiroyuki
• Nikon Corp

Inventors

• Tanitsu Osamu
• Shigematsu Koji
• Hirota Hiroyuki

Classifications

• F21V13/02

  Combinations of only two kinds of elements · CPC title

• G03F7/70191

  Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like · CPC title

• G03F7/701

  Off-axis setting using an aperture · CPC title

• G02B27/0977

  Reflective elements · CPC title

• G02B27/286

  for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another (G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34) · CPC title