Optical apparatus

• US 20030081210A1
• Filed: 10/25/2002
• Published: 05/01/2003
• Est. Priority Date: 10/26/2001
• Status: Active Grant

• Current Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Original Assignee: Canon Ayutthaya Limited (Canon Inc.)
• Inventors: Miyake, Akira, Masaki, Fumitaro
• Granted Patent: US 6,999,172 B2
• Time in Patent Office: Days
• US Class Current: 356/369
• CPC Class Codes: G01N 21/21 Polarisation-affecting properties G01N21/19 takes precedence
• CPC Class Codes: G01N 23/20 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
• CPC Class Codes: G03F 7/70566 Polarisation control

Abstract

An optical apparatus that measures a polarization dependent characteristic of a measured object includes a light source for emitting non-linearly polarized light in an extreme ultraviolet region or an X-ray region, and a rotary polarizer for reflecting the light emitted from the light source, the polarizer including a set of mirrors repeating three or more reflections and being arranged such that an optical axis of incident light and that of outgoing light are aligned with the same straight line.

Claims

1. An optical apparatus that measures a polarization dependent characteristic of a measured object, said optical apparatus comprising:

a light source for emitting non-linearly polarized light in an extreme ultraviolet region or an X-ray region; and

a rotary polarizer for reflecting the light emitted from said light source, said polarizer including a set of mirrors repeating three or more reflections and being arranged such that an optical axis of incident light and that of outgoing light are aligned with the same straight line.

2. An optical apparatus according to claim 1, wherein a polarization plane of the light used to irradiate the measured object varies when the rotary polarizer rotates.

3. An optical apparatus according to claim 1, wherein said polarizer rotates around the optical axis of the incident light as a central axis.

4. An optical apparatus according to claim 1, wherein said polarizer is retractable against a light path of the light emitted from said light source.

5. An optical apparatus according to claim 1, comprising:

an optical system for directing the outgoing light from said polarizer to the measured object, wherein said polarizer is arranged in place substantially conjugate with the optical system.

6. An optical apparatus according to claim 1, wherein said polarizer is arranged close to the measured object.

7. An optical apparatus according to claim 1, wherein the light source is an LPP light source.

8. An optical apparatus according to claim 1, further comprising a monochrometer for introducing to the polarizer light having a desired wavelength among the light from the light source.

9. An optical apparatus according to claim 8, wherein the set of mirrors include a multilayer mirror having a predetermined layer thickness distribution, and moving in accordance with the wavelength of the light from the monochrometer.

10. An optical apparatus according to claim 1, wherein the polarization dependent characteristic of the measured object is reflectance.

11. An optical apparatus according to claim 1, wherein the polarization dependent characteristic of the measured object is a spectrum of a photoelectron emitted from the measured object.

12. An optical element whose polarization dependent characteristic is measured by using an optical apparatus that measures polarization dependent characteristics of a measured object, the optical apparatus comprising a light source for emitting non-linearly polarized light in an extreme ultraviolet region or an X-ray region, and a rotary polarizer for reflecting the light emitted from the light source, the rotary polarizer including a set of mirrors repeating three or more reflections and being arranged such that the optical axis of incident light and that of outgoing light are aligned with the same straight line, the characteristic measured being more than a specified value.

13. An optical element according to claim 12, wherein the optical element is a mirror, diffraction grating, an optical film, a light integrator, or a combination thereof.

14. An exposure apparatus for irradiating exposure light to a target via an optical system including an optical element whose polarization dependent characteristic is measured by using an optical apparatus that measures polarization dependent characteristics of a measured object, the optical apparatus comprising a light source for emitting non-linearly polarized light in an extreme ultraviolet region or an X-ray region, and a rotary polarizer for reflecting the light emitted from the light source, the rotary polarizer including a set of mirrors repeating three or more reflections and being arranged such that the optical axis of incident light and that of outgoing light are aligned with the same straight line, the characteristic measured being more than a specified value.

15. A device fabricating method comprising the steps of:

exposing a target using an exposure apparatus that irradiates exposure light to an object to be exposed via an optical system including an optical element whose polarization dependent characteristic is measured by using an optical apparatus that measures polarization dependent characteristics of a measured object, the optical apparatus comprising a light source for emitting non-linearly polarized light in an extreme ultraviolet region or an X-ray region, and a rotary polarizer for reflecting the light emitted from the light source, the rotary polarizer including a set of mirrors repeating three or more reflections and being arranged such that the optical axis of incident light and that of outgoing light are aligned with the same straight line, the characteristic measured being more than specified values; and

performing a predetermined process for the target exposed.