Optical system,exposure system, and exposure method

• US 20100141926A1
• Filed: 02/05/2010
• Published: 06/10/2010
• Est. Priority Date: 01/27/2004
• Status: Abandoned Application

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Omura, Yasuhiro
• Application Number:
  US12/656,636
• Publication Number:
  US 20100141926A1
• Time in Patent Office: Days
• US Class Current: 355/77
• CPC Class Codes: G02B 13/143 for use with ultraviolet radiation
• CPC Class Codes: G02B 17/08 Catadioptric systems used in non-imaging applications G02B19/00
• CPC Class Codes: G02B 17/0892 specially adapted for the UV
• CPC Class Codes: G02B 27/28 for polarising used in stereoscopes G02B30/25
• CPC Class Codes: G03F 7/70091 Illumination settings, i.e. intensity distribution in the pupil plane or angular distribution in the field plane; On-axis or off-axis settings, e.g. annular, dipole or quadrupole settings; Partial coherence control, i.e. sigma or numerical aperture [NA]
• CPC Class Codes: G03F 7/70191 Optical correction elements, filters or phase plates for controlling intensity, wavelength, polarisation, phase or the like
• CPC Class Codes: G03F 7/70566 Polarisation control
• CPC Class Codes: G03F 7/70966 Birefringence

Abstract

An optical system is able to achieve a substantially azimuthal polarization state in a lens aperture while suppressing loss of light quantity, based on a simple configuration. The optical system of the present invention is provided with a birefringent element for achieving a substantially circumferential distribution or a substantially radial distribution as a fast axis distribution in a lens aperture, and an optical rotator located behind the birefringent element and adapted to rotate a polarization state in the lens aperture. The birefringent element has an optically transparent member which is made of a uniaxial crystal material and a crystallographic axis of which is arranged substantially in parallel with an optical axis of the optical system. A light beam of substantially spherical waves in a substantially circular polarization state is incident to the optically transparent member.

Claims

1. A device fabrication method comprising:

preparing a photosensitive substrate; and

exposing a pattern to be transferred, on the photosensitive substrate through an optical system;

wherein the optical system comprises a birefringent element, an optical rotator, and an optical member including a predetermined power, and

wherein the exposing comprises making a beam bundle including passed through the birefringent element, pass in order through the optical member including the predetermined power and through the optical rotator.

2. The device fabrication method according to claim 1,

wherein the optical system includes an illumination optical system, and

wherein the exposing includes an illumination step for illuminating the predetermined pattern through the optical system.

3. The device fabrication method according to claim 2,

wherein the birefringent element is located near the predetermined pattern surface, or at or near a position optically conjugate with the predetermined pattern surface, in an optical path of the illumination optical system, and

wherein the illuminating includes establishing the position optically conjugate with the predetermined pattern surface, by the optical member including the predetermined power.

4. The device fabrication method according to claim 3,

wherein the birefringent element is located at or near the position optically conjugate with the predetermined pattern surface, in the optical path of the illumination optical system, and

wherein the establishing the position optically conjugate with the predetermined pattern surface comprises making a beam bundle pass through the optical rotator.

5. The device fabrication method according to claim 3,

wherein the illuminating comprises forming a secondary light source including a predetermined optical intensity distribution, on an illumination pupil plane, and

wherein the predetermined optical intensity distribution of the secondary light source is so set that an optical intensity in a pupil center region being a region on the illumination pupil and including an optical axis is smaller than an optical intensity in a region around the pupil center region.

6. The device fabrication method according to claim 5,

wherein the predetermined optical intensity distribution of the secondary light source includes an optical intensity distribution of an annular shape or multi-pole shape.

7. The device fabrication method according to claim 3,

wherein the birefringent element is located at or near the position optically conjugate with the predetermined pattern surface, in the optical path of the illumination optical system,

wherein the illuminating comprises guiding a beam bundle from an optical integrator to the predetermined pattern surface, and

wherein the beam bundle including passed through the optical integrator is incident to the optical rotator.

8. The device fabrication method according to claim 1,

wherein the optical system includes a projection optical system, and

wherein the exposing includes forming an image of the predetermined pattern on a surface of the photosensitive substrate through a liquid.