JP2830582B2 - Lighting shape deformation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination optical system used in a projection exposure apparatus.

[0002]

2. Description of the Related Art As a method for improving the resolving power of a projection exposure apparatus, the shape of illumination light is transformed into an annular light beam 21 as shown in FIG. 2A, or a multi-divided light beam as shown in FIG. 14 is known. In order to realize such a shape of the light source, the proceedings of the 52nd Autumn Meeting of the Japan Society of Applied Physics (1991) p. 600 "Study of Light Source Shape to Improve Resolution" 600
-601 "Reduced projection exposure method using modified light source (I),
3 (a) or 3 (b), a filter as shown in FIG. 3 (a) or 3 (b) is inserted as a stop into the illumination system. In FIG. 3, reference numeral 31 denotes a light transmitting portion, and 32 denotes a light shielding portion.

[0003]

By inserting a filter, the shape of illumination light is deformed, but at the same time, the amount of illumination light is reduced by the amount of light blocked by the filter.

[0004] It is an object of the present invention to provide an illumination shape deforming apparatus which deforms a shape without reducing the amount of illumination light.

[0005]

A first invention is a parallel light beam.
For deforming the illumination shape of an illumination system having a light source for emitting light
In the installation, equipped with a prism that is rotated by a motor,
The parallel light beam incident on the prism from the light source is
Make a ring shape at the exit surface of the rhythm, and use the illumination light
It is characterized in that the shape is deformed without reducing the amount of light .

A second invention provides a light source for emitting a parallel light beam.
Device for deforming the illumination shape of an illumination system having a cone
Mirror consisting of a mirror shaped like a mirror and a mirror rotated by a motor
A mirror system which is incident on the mirror system from the light source.
The row light beam becomes annular at the exit surface of the mirror system.
Unishi is characterized and this <br/> deforming a shape without deforming the light amount of the illumination light.

Further , an illumination device having a light source for emitting a parallel light beam is provided.
In a device that transforms a bright illumination shape, a polygonal pyramid
Parallelism incident on the prism from the light source
The light beam is divided into peripheral portions at the exit surface of the prism.
You may make it.

[0008] Further, a light source for emitting a parallel light beam is provided.
In a device that changes the illumination shape of the illumination system,
Parallelism incident on the prism from the light source
So that the luminous flux has a ring shape at the exit surface of the prism
You may do it.

Further, a light source for emitting a parallel light beam is provided.
In a device for deforming the illumination shape of a lighting system,
A light source comprising a mirror system comprising a plurality of
The parallel light beam incident on the mirror system is
The exit surface may be divided into peripheral portions.

An illumination device having a light source for emitting a parallel light beam is provided.
In a device that changes the shape of light-based lighting,
A mirror system consisting of two mirrors,
The parallel light beam incident on the mirror system is incident on the exit surface of the mirror system.
Alternatively, it may be formed in a ring shape.

[0011]

In the projection exposure apparatus, the image of the light source is formed on the pupil plane of the imaging optical system. When illumination light having a shape as shown in FIGS. 2A and 2B is used, the center of the pupil plane becomes dark. Also, the object plane (where the photomask is placed) and the pupil plane are in a conjugate relationship,
A Fourier transform image of the light transmitted through the photomask is generated on the pupil plane. Therefore, when the illumination light as shown in FIGS. 2A and 2B is used, the low-frequency component of the Fourier transform image decreases, and the high-frequency component relatively increases. Since the Fourier transform of a fine pattern includes many high frequency components, the resolution is improved.

If a light beam is deformed by bending a light beam using a prism or a mirror, the central portion of the light beam can be darkened without reducing the overall light amount.

[0013]

FIG. 1 shows an embodiment of the first invention. This illumination shape deformation device uses a polygonal pyramid-shaped prism 11. FIG.
1A is a top view, and FIG. 1B is a side view. Since the light beam 12 is refracted by the polygonal pyramidal prism 11, the parallel light beam 13 (FIG. 1C) incident on the prism is split into a light beam 14 (FIG.
(D)).

FIG. 4 shows an embodiment of the second invention of the present invention. This illumination shape deformation device uses a conical prism 41. FIG. 4A is a top view, and FIG. 4B is a side view. Since the light beam 12 is refracted by the conical prism 41, the parallel light beam 13 (FIG. 4C) incident on the prism is converted into an annular light beam 21 (FIG. 4C) on the exit surface of the prism.
(D)).

FIG. 5 shows an embodiment of the third invention. This illumination shape deforming apparatus uses a prism 51 attached to a motor 52. FIG. 5A is a side view thereof.
The light rays 12 are refracted by the prism 51. Since the prism is rotated by the motor, the parallel light flux 13 (FIG. 5B) incident on the prism becomes an annular light flux 21 (FIG. 5C) when time-averaged on the exit surface of the prism. Such an apparatus has an effect of reducing coherence, particularly in the case of light having high coherence such as a laser light source, because the position of a light beam changes with time.

FIG. 6 shows an embodiment of the fourth invention. This illumination shape deformation device uses two polygonal pyramid-shaped mirrors 61 and 62. FIG. 6A is a top view, and FIG. 6B is a side view. Since the light beam 12 is refracted by the two polygonal pyramid-shaped mirrors 61 and 62, the parallel light flux 13 (FIG.
FIG. 6C shows a light beam 14 (FIG. 6D) divided into peripheral portions on the exit surface of the mirror system. An apparatus using such a reflection optical system is particularly effective for an apparatus such as an excimer laser light source, which has no glass material having a high transmittance due to a short wavelength.

FIG. 7 shows an embodiment of the fifth invention. This illumination shape deformation device uses two conical mirrors 71 and 72. FIG. 7A is a top view, and FIG. 7B is a side view. Since the light beam 12 is refracted by the two conical mirrors 71, the parallel light flux 13 entering the prism (FIG. 7C)
Is an annular luminous flux 21 (FIG. 7) at the exit surface of the mirror system.
(D)).

FIG. 8 shows an embodiment of the sixth invention. This illumination shape deforming device uses a mirror 81 and a conical mirror 82 attached to a motor 52. FIG. 8A is a top view, and FIG. 8B is a side view. The light beam 12 is refracted by the mirror 81 and the conical mirror 82. Since the mirror 81 is rotated by the motor, the parallel light flux 13 (FIG. 8C) incident on the mirror system becomes an annular light flux 21 (FIG. 8D) when time averaged on the exit surface of the prism.

[0019]

According to the first to sixth aspects of the present invention, the shape of illumination light can be changed without reducing the amount of illumination light. Further, the illumination shape deforming devices of the third and sixth inventions have an effect of reducing the coherence of the illumination light.

[Brief description of the drawings]

FIG. 1 is a view showing an embodiment of the first invention, (a) is a top view, (b) is a side view, (c) is a cross-sectional view of an incident light beam,
(D) is a sectional view of the emitted light beam.

FIG. 2A is a diagram showing an annular luminous flux, and FIG. 2B is a diagram showing a multi-divided luminous flux.

3A is a diagram illustrating an annular filter, and FIG. 3B is a diagram illustrating a multi-segment filter.

4 (a) is a top view, FIG. 4 (b) is a side view, FIG. 4 (c) is a sectional view of an incident light beam,
(D) is a sectional view of the emitted light beam.

5 (a) is a side view, FIG. 5 (b) is a sectional view of an incident light beam, and FIG. 5 (c) is a sectional view of an output light beam.

6 (a) is a top view, FIG. 6 (b) is a side view, FIG. 6 (c) is a sectional view of an incident light beam,
(D) is a sectional view of the emitted light beam.

7 (a) is a top view, FIG. 7 (b) is a side view, FIG. 7 (c) is a sectional view of an incident light beam,
(D) is a sectional view of the emitted light beam.

8 (a) is a top view, FIG. 8 (b) is a side view, FIG. 8 (c) is a sectional view of an incident light beam,
(D) is a sectional view of the emitted light beam.

[Explanation of symbols]

 11 Polygonal pyramid prism 41 Conical prism 52 Motor 51 Prism 61, 62 Polygonal pyramid mirror 71, 72, 82 Conical mirror 81 Mirror

Claims (2)

(57) [Claims] 1. An illumination system having a light source for emitting a parallel light beam.
In an apparatus for deforming an illumination shape, a prism rotated by a motor is provided.
The parallel light beam incident on the prism exits the prism
To reduce the amount of illumination light
An illumination shape deformation device characterized by deforming a shape without causing the shape to be deformed . 2. An illumination system having a light source for emitting a parallel light beam.
A device that changes the shape of the illumination, consisting of a conical mirror and a mirror that rotates with a motor
And a mirror system, which is incident on the mirror system from the light source.
The collimated light beam forms an annular shape at the exit surface of the mirror system.
And deform the shape without reducing the amount of illumination light.
Illumination shape deformation and wherein the that.