Illumination device

• US 9,760,012 B2
• Filed: 07/31/2012
• Issued: 09/12/2017
• Est. Priority Date: 08/04/2011
• Status: Active Grant

• Current Assignee: Nikon Corporation
• Original Assignee: Nikon Corporation
• Inventors: Komatsuda, Hideki
• Primary Examiner(s): Iacoletti, Michelle M
• Application Number:
  US14/236,742
• Publication Number:
  US 20140218705A1
• Time in Patent Office: 1,869 Days
• CPC Class Codes: G03F 7/70058 Mask illumination systems
• CPC Class Codes: G03F 7/70075 Homogenization of illumination intensity in the mask plane by using an integrator, e.g. fly's eye lens, facet mirror or glass rod, by using a diffusing optical element or by beam deflection
• 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

Abstract

An illumination optical system that illuminates a target surface includes a first deflector, a second deflector, and an optical integrator. The first deflector is arranged on a first face crossing an optical path of light from a light source and has a period in a first direction defined on the first face. The second deflector is arranged on a second face crossing an optical path of light from the first deflector and has a period in a second direction defined on the second face. The optical integrator has a plurality of wavefront division facets arrayed on a third face crossing an optical axis of light from the second deflector. At least one of the first and second deflectors rotates about an optical axis of the illumination optical system or about an axis parallel to the optical axis in order to adjust a pattern of an illumination distribution.

Claims

1. An illumination optical system configured to illuminate an illumination target surface with light from a light source, comprising:

a first deflector which is arranged on a first face crossing an optical path of the light from the light source and has a structure with a period in a first direction, the first direction defined on the first face;

a second deflector which is arranged on a second face crossing an optical path of light from the first deflector and has a structure with a period in a second direction, the second direction defined on the second face;

an optical integrator which has a plurality of wavefront division facets arrayed on a third face, the third face crossing an optical axis of light from the second deflector; and

a rotation driver which rotates at least one of the first deflector and the second deflector,

wherein at least one of the first and second deflectors rotates about an optical axis of the illumination optical system or about an axis parallel to the optical axis in order to adjust a pattern of an illumination distribution.

2. The illumination optical system according to claim 1, wherein

the periods of the first and second deflectors are different from each other.

3. The illumination optical system according to claim 1, wherein

the periods of the first and second deflectors are equal to each other.

4. The illumination optical system according to claim 1, wherein

the light from the second deflector has an illumination distribution which periodically changes on the third face.

5. The illumination optical system according to claim 4, wherein

the illumination distribution changes by rotation of at least one of the first deflector and the second deflector.

6. The illumination optical system according to claim 1, wherein

at least one of the first deflector and the second deflector moves in a direction crossing the optical axis.

7. The illumination optical system according to claim 1, wherein

the rotation driver rotates at least one of the first deflector and the second deflector so as to change a difference depending upon positions on the illumination target surface, in an angular distribution of light intensity within an aperture of light focused on the illumination target surface.

8. An exposure apparatus comprising:

the illumination optical system as set forth in claim 1 which illuminates a master disposed on the illumination target surface; and

a projection optical system which projects the master onto a photosensitive substrate.

9. The exposure apparatus according to claim 8, wherein

the rotation driver rotates at least one of the first deflector and the second deflector so as to change a difference depending upon the master, in an angular distribution of light intensity within an aperture of light focused on the master.

10. An illumination method for illuminating an illumination target surface with light from a light source, comprising:

letting the light from the light source enter a first deflector which has a structure with a period in a first direction, the first direction defined on a first face, the first face crossing an optical path of the light from the light source;

letting light from the first deflector enter a second deflector which has a structure with a period in a second direction, the second direction defined on a second face, the second face crossing an optical path of the light from the first deflector;

letting light from the second deflector enter a plurality of wavefront division facets arrayed on a third face, the third face crossing an optical axis of the light from the second deflector;

rotating at least one of the first deflector and the second deflector by a rotation driver in order to adjust a pattern of an illumination distribution; and

illuminating the illumination target surface, using light via the wavefront division facets.

11. An exposure method comprising:

illuminating a master disposed on the illumination target surface, using the illumination method as set forth in claim 10; and

projecting the master onto a photosensitive substrate.

12. A device manufacturing method comprising:

performing exposure to transfer an exposure pattern onto the photosensitive substrate, using the exposure method as set forth in claim 11;

developing the photosensitive substrate onto which the exposure pattern has been transferred, to form a mask layer in a shape corresponding to the exposure pattern on a surface of the photosensitive substrate; and

processing the surface of the photosensitive substrate through the mask layer.