CN110431487B

CN110431487B - Illumination apparatus and method, exposure apparatus and method, and device manufacturing method

Info

Publication number: CN110431487B
Application number: CN201880018873.1A
Authority: CN
Inventors: 加藤正纪
Original assignee: Nikon Corp
Current assignee: Nikon Corp
Priority date: 2017-03-17
Filing date: 2018-03-15
Publication date: 2021-08-10
Anticipated expiration: 2038-03-15
Also published as: JP7116368B2; JP6806236B2; CN110431487A; JP2021047444A; WO2018168993A1; JPWO2018168993A1; KR20190117642A; KR102315115B1

Abstract

An illumination device that illuminates a mask, comprising: a light source generating illumination light; a variable magnification optical system for adjusting the maximum inclination angle of the illumination light; an optical fiber for branching the illumination light passing through the variable magnification optical system while maintaining an inclination angle; an input lens for converting the illumination light emitted from the emission end of the optical fiber into a parallel light beam; an aperture diaphragm for adjusting the numerical aperture of the illumination light; and a condenser lens for guiding the illumination light with the adjusted numerical aperture to a mask. The utilization efficiency of illumination light can be improved according to the illumination condition.

Description

Illumination apparatus and method, exposure apparatus and method, and device manufacturing method

Technical Field

The present invention relates to an illumination technique for illuminating an object with illumination light, an exposure technique using the illumination technique, and a device manufacturing technique using the exposure technique.

Background

Conventionally, in a photolithography process for manufacturing electronic devices such as liquid crystal display devices, semiconductor devices, thin film magnetic heads, and the like, an exposure apparatus is used to transfer a pattern of a mask illuminated by an illumination apparatus onto a substrate such as a plate material coated with a photosensitive agent such as a photoresist via a projection optical system.

As a conventional illumination device, there has been used an illumination device including an optical system including a plurality of conical or pyramidal optical members for controlling the cross-sectional shape of an illumination beam from a mercury lamp, and the cross-sectional shape of the illumination beam is controlled by using the optical system in accordance with the shape of an annular illumination light source in order to improve the utilization efficiency of illumination light at the time of annular illumination (see, for example, patent document 1).

In the exposure apparatus, an illumination method other than the ring illumination is also used. In such a case, it is also desirable to improve the utilization efficiency of the illumination light.

Documents of the prior art

Patent document

Patent document 1: specification of U.S. Pat. No. 5,719,704

Disclosure of Invention

According to the 1 st aspect, there is provided an illumination device for illuminating a mask, comprising: a light source generating illumination light; an optical system that adjusts an inclination angle of the illumination light; a1 st condensing optical system that condenses the illumination light passed through the optical system; an optical member that emits the illumination light passing through the optical system to the 1 st condensing optical system while maintaining the inclination angle of the illumination light; an aperture stop for adjusting the numerical aperture of the illumination light emitted from the 1 st condensing optical system; and a2 nd condensing optical system for guiding the illumination light whose numerical aperture is adjusted to the mask.

According to the 2 nd aspect, there is provided an exposure apparatus for exposing a pattern of a mask onto a substrate, comprising: the lighting device according to claim 1; and a projection optical system that forms an image of the pattern of the mask illuminated by the illumination device onto a substrate.

According to the 3 rd aspect, there is provided an illumination method for illuminating a mask, comprising: adjusting an inclination angle of illumination light generated from a light source; emitting the illumination light with the adjusted tilt angle through an optical member that maintains the tilt angle of the illumination light; condensing the emitted illumination light; adjusting the numerical aperture of the illumination light; and directing the illumination light with the adjusted numerical aperture to the mask.

According to the 4 th aspect, there is provided an exposure method for exposing a pattern of a mask onto a substrate, comprising: illuminating the mask using the illumination method of form 3; and forming an image of the illuminated pattern of the mask onto a substrate.

Drawings

Fig. 1 is a perspective view showing a schematic configuration of an exposure apparatus according to an embodiment.

Fig. 2 is a diagram showing a configuration of an illumination device according to an embodiment.

Fig. 3 is a diagram showing the configurations of a partial projection optical system and a stage system according to an embodiment.

Fig. 4 is a flowchart showing an example of the illumination method and the exposure method.

Fig. 5 (a) is a diagram showing the main part of the illumination device when the σ value of the illumination light is large, and fig. 5 (B) is a diagram showing the main part of the illumination device when the σ value of the illumination light is small.

Fig. 6 (a) is a diagram showing a main part of the illumination device of the comparative example, fig. 6 (B) is a diagram showing a light intensity distribution at the incident end of the optical fiber, and fig. 6 (C) is a diagram showing a light intensity distribution at the incident end of the fly eye lens.

Fig. 7 (a) is a view showing a partial illumination optical system, and fig. 7 (B) is an enlarged view showing an emission end of the optical fiber in fig. 7 (a).

Fig. 8 (a) is a diagram showing an example of the aperture stop in the annular illumination, fig. 8 (B) is a diagram showing an example of the aperture stop in the large σ illumination, and fig. 8 (C) is a diagram showing an example of the aperture stop in the small σ illumination.

Fig. 9 (a) and 9 (B) are conceptual views illustrating the emission surface of the fly-eye lens.

Fig. 10 (a) is a diagram showing a configuration example of a variable magnification optical system, fig. 10 (B) is a diagram showing a configuration example of a switching optical system, and fig. 10 (C) is a diagram showing an example of an optical member for controlling an inclination angle of a laser beam.

Fig. 11 is a flowchart showing an example of the method for manufacturing an electronic component.

Detailed Description

An embodiment will be described with reference to fig. 1 to 9 (B). Fig. 1 is a perspective view showing an exposure apparatus EX according to the present embodiment. In the present embodiment, the exposure apparatus EX is a step-and-scan type exposure apparatus that transfers an image of a pattern formed on a mask M onto a flat plate-shaped plate material P as a substrate coated with a photosensitive agent while moving the mask M and the plate material P in synchronization with a projection optical system PL having a plurality of catadioptric partial projection optical systems.

In fig. 1, the X axis and the Y axis are taken to be orthogonal to each other in a plane parallel to the plate material P, and the Z axis is taken to be perpendicular to the plane (XY plane). For example, the XY plane is set to be a plane parallel to the horizontal plane, and the Z axis is set to be parallel to the vertical line. In the present embodiment, the scanning direction, which is the direction in which the mask M and the plate material P are moved synchronously, is set to be a direction (X direction) parallel to the X axis. In this case, the non-scanning direction orthogonal to the scanning direction is a direction (Y direction) parallel to the Y axis.

The exposure apparatus EX includes: an illumination device ILA for illuminating a pattern surface (hereinafter also referred to as a mask surface) of a mask M supported on a mask stage MST (see fig. 3) with illumination light having a uniform illuminance distribution; a projection optical system PL; and a control unit 30 including a computer for controlling the operation of the entire apparatus. The illumination device ILA illuminates a plurality of (4 in this case)

illumination regions

21a, 21c, 21e, and 21g in the 1 st column arranged on the mask surface along the Y direction (non-scanning direction), and illuminates a plurality of (3 in this case) illumination regions (not shown) in the 2 nd column located between the illumination regions 21a to 21g in a state of being shifted in the scanning direction (X direction) with respect to the illumination regions 21a to 21g in the 1 st column. In this way, although the illumination device ILA illuminates 7 illumination regions on the mask surface, the arrangement and the number of the illumination regions are arbitrary.

In the present embodiment, since the field stop is disposed in the projection optical system PL as described later, the illumination regions 21a to 21g may have a shape slightly larger than the image of the field stop on the mask surface. As shown in fig. 2, the illumination device ILA includes 3

light sources

2a, 2b, and 2c including an ultra-high pressure mercury lamp.

Illumination light

3a, 3b, and 3c emitted from the

light sources

2a, 2b, and 2c are condensed by

elliptical mirrors

4a, 4b, and 4c, respectively. The light sources 2a to 2c are arranged at the 1 st focal positions of the elliptical mirrors 4a to 4c, and

light source images

5a, 5b, and 5c of the

light sources

2a, 2b, and 2c are formed at the 2 nd focal positions of the

elliptical mirrors

4a, 4b, and 4 c. While the mask M is not illuminated, the

illumination lights

3a, 3b, 3c are shielded by shutters (not shown) arranged near the 2 nd focal points of the

elliptical mirrors

4a, 4b, 4 c. The number of the

light sources

2a, 2b, and 2c is arbitrary, and one light source (for example, only the light source 2a) may be used.

Illumination light

3a, 3b, and 3c emitted as divergent light from the

light source images

5a, 5b, and 5c are collected to the incident ends 12a, 12b, and 12c of the optical fiber 10 by the variable magnification

optical systems

8a, 8b, and 8c, respectively. The variable magnification

optical systems

8a, 8b, and 8c form variable magnification images (hereinafter, referred to as light source images) 9a, 9b, and 9c of the

light source images

5a, 5b, and 5c on the incident surfaces of the incident ends 12a, 12b, and 12c, respectively. For example, the variable power optical systems 8a to 8c are zoom lenses (zoom optical systems) including a front group lens system 6 and a rear group lens system 7, the front group lens system 6 is movable along the optical axis by a driving unit 6a, and the rear group lens system 7 is movable along the optical axis by a driving unit 7 a. The control unit 30 controls the positions of the front group lens system 6 and the rear group lens system 7 via the

driving units

6a and 7a, thereby controlling the magnifications of the variable power optical systems 8a to 8 c.

Here, the height (image height) of the light source image 9a when the magnification-varying optical system 8a is set to the minimum magnification is y1, and the maximum inclination angle of the illumination light 3a forming the light source image 9a with respect to the optical axis at this time is α 1. When the magnification of the magnification-varying optical system 8a is higher than the maximum magnification of the magnification, the height of the light source image 9a is y2, and the maximum inclination angle of the illumination light 3a with respect to the optical axis at this time is α 2. The so-called maximum inclination angle is also 1/2 for the so-called cone angle. In addition, when the light intensity distribution of the light source image 9a is in a normal distribution (gaussian distribution), the height of the light source image 9a may be regarded as a position where the light intensity is, for example, about 10% to 50% of the maximum intensity or an interval of positions where the light intensity is, for example, about 30% in the light intensity distribution. When the variable magnification optical system 8a satisfies the sine condition, the following relationship is established.

y1·sinα1＝y2·sinα2…(1)

Here, the height y2 is higher than the height y1, and thus the inclination angle α 2 is smaller than the inclination angle α 1 according to the formula (1). Accordingly, the variable magnification optical systems 8a to 8c are also optical systems capable of controlling or adjusting the maximum inclination angle of the illumination light incident on the incident ends 12a to 12c by forming the variable magnification light source images 9a to 9 c. In the present embodiment, the magnification-varying optical systems 8a to 8c are controlled to have the same magnification.

The optical fiber 10 as a light transmission member is a fiber bundle formed by randomly bundling a large number of optical fiber cores 11 (see fig. 5 a), and has 3

incident ends

12a, 12B, 12c and a plurality of (here, 7) emission ends (only the emission ends 14a, 14B are shown in fig. 2) corresponding to a plurality of (here, 7) illumination regions, and the illumination lights 3a to 3c received from the incident ends 12a to 12c are distributed to the plurality of emission ends. Thus, at least a part of each of the illumination lights 3a to 3c is emitted from the plurality of emission ends, and the illumination device ILA can mix the illumination lights emitted from the plurality of light sources 2a to 2c and emit them. Here, the optical fiber 10 is configured to distribute and emit the illumination light received from the incident ends 12a to 12c to the plurality of emission ends at substantially the same light quantity ratio.

The optical fiber core 11 emits the incident light beam while maintaining the inclination angle of the incident light beam so that the maximum inclination angle of the incident light beam is substantially equal to the maximum inclination angle of the emitted light beam. Therefore, the maximum inclination angles of the illumination lights 3a to 3c incident on the incident ends 12a to 12c of the optical fiber 10 are substantially equal to the maximum inclination angles of the illumination lights emitted from the plurality of emission ends. As an example, the illumination light emitted from the variable magnification optical systems 8a to 8c enters the corresponding entrance ends 12a to 12c in a state where the principal rays are parallel to the optical axis, that is, in a so-called telecentric state. This makes it possible to uniformly irradiate the illumination light in the range of the incident angle that can be transmitted by each optical fiber core wire 11 of the optical fiber 10. Further, the maximum inclination angle of the illumination light emitted from the magnification-varying optical systems 8a to 8c is controlled within a range smaller than the maximum incident angle (inclination angle) transmittable by the optical fiber core wire 11.

The illumination lights 20a, 20c and the like emitted from the plurality of emission ends 14a, 14b and the like of the optical fiber 10 are incident on a plurality of (here, 7) local illumination optical systems IL1 to IL7 (the local illumination optical systems IL2 and IL4 to IL7 are not shown) having the same configuration as each other for illuminating the

local illumination regions

21a, 21c and the like of the mask M, respectively. The local illumination optical systems IL1 to IL7 are associated with local projection optical systems PL1 to PL7, respectively, which will be described later, and are arranged in a zigzag pattern along a non-scanning direction (Y direction) orthogonal to the scanning direction.

In the local illumination optical systems IL1 and IL3, the

illumination lights

20a and 20c emitted from the emission ends 14a and 14b of the optical fiber 10 are condensed by the input lens 15 as a collimator lens, converted into parallel beams, and then incident on the fly eye lens 16 as an optical integrator. The illumination lights 20a and 20c incident on the fly eye lens 16 are wavefront-divided by a large number of lens units constituting the fly eye lens 16, and form a secondary light source (surface light source) including a plurality of light source images on a rear focal plane (exit pupil plane of the illumination optical system) near an exit plane thereof. An aperture stop 17 is disposed on the rear focal plane. The control unit 30 controls the size and shape of the aperture stop 17 via the drive unit 17 a. This makes it possible to control the numerical aperture NA of the illumination light illuminating the mask M by the local illumination optical systems IL1 and IL 3. Hereinafter, the numerical aperture NA of the illumination light is expressed using a value σ as a coherence factor (a value obtained by dividing the numerical aperture of the illumination light illuminating the mask by the numerical aperture on the mask side of the projection optical system). Therefore, the aperture stop 17 can also be referred to as a σ stop. In the case of ring illumination, the aperture stop 17 may be replaced with a ring illumination aperture stop (not shown) having a ring-shaped aperture with a variable size.

Illumination lights

20a and 20c emitted from the apertures of the aperture stop 17 illuminate

illumination areas

21a and 21c corresponding to the mask M with a substantially uniform illuminance distribution via the condenser lens 18. The local illumination optical systems IL2 and IL4 to IL7, not shown, have the same configuration as the local illumination optical system IL1, and the local illumination optical systems IL2 and IL4 to IL7 illuminate the illumination regions corresponding to the respective local illumination optical systems IL1 on the mask M with a substantially uniform illuminance distribution.

Illumination light from the illumination regions 21a to 21g on the mask M corresponding to the local illumination optical systems IL1 to IL7 is incident on the local projection optical systems PL1 to PL7, respectively. Fig. 3 is a diagram showing a structure of a partial projection optical system PL 1. As shown in fig. 3, the partial projection optical system PL1 includes: a1 st catadioptric optical system PL11 that forms an intermediate image of a pattern provided in the illumination region 21a corresponding to the mask surface at the aperture portion of the field stop 22; and a2 nd catadioptric optical system PL12 that forms an image of the pattern of the mask M as an equi-magnification erect image on the exposure region 23a of the sheet material P supported by the sheet material stage PST in cooperation with the 1 st catadioptric optical system PL 11. The partial projection optical systems PL2 to PL7 have the same configuration as the partial projection optical system PL1, and form images of patterns formed in the illumination regions corresponding to the mask surfaces on the plate material P. The partial projection optical systems PL1 to PL7 are arranged in a zigzag pattern along the non-scanning direction.

In fig. 2, a power supply device 32 for supplying power to the light sources 2a to 2c is connected to the control unit 30. When performing exposure of the plate material P or calibration of the illumination device ILA, the control unit 30 turns on the light sources 2a to 2c via the power supply device 32. In addition, when the required exposure amount is small, only at least one of the light sources 2a to 2c may be turned on.

As a basic operation at the time of exposure, the control unit 30 sets illumination conditions including a σ value of illumination light and the magnification of the variable magnification optical systems 8a to 8c (described in detail later), and turns on the light sources 2a to 2 c. Then, by repeating the illumination of mask M by illumination device ILA and the driving of mask stage MST supporting mask M and plate material stage PST supporting plate material P, mask M and plate material P are moved synchronously in the scanning direction with respect to partial projection optical systems PL1 to PL7 (scanning exposure); and moving the plate material P in the non-scanning direction or the scanning direction (step movement), thereby exposing an image of the pattern formed on the mask M to a plurality of exposed regions of the plate material P in a step-and-scan manner.

When the illumination device ILA is calibrated, for example, illuminance sensors (not shown) are disposed at a plurality of positions in each of the illumination areas 21a to 21 g. When the light sources 2a to 2c are turned on and the σ value is changed and when the magnifications of the variable magnification optical systems 8a to 8c are changed, the illuminance distributions measured by the illuminance sensors are adjusted so that the illuminance distributions are converged within a predetermined allowable range with respect to the target distribution, and thus the illuminance distributions are uniform, by the variable magnification optical systems 8a to 8c and the local illumination optical systems IL1 to IL 7.

An example of the operation of the illumination method including the setting of the illumination condition of the illumination apparatus ILA and the exposure method using the exposure apparatus EX according to the present embodiment will be described below with reference to the flowchart of fig. 4. The operation is controlled by the control unit 30.

First, in a state where the light sources 2a to 2c are not turned on, in step 102 of fig. 4, the σ value of the illumination light is controlled using the aperture stop 17 of the local illumination optical systems IL1 to IL7 of the illumination apparatus ILA in accordance with the type, fineness, and the like of the pattern of the mask M to be exposed. In the case of ring illumination, the aperture stop 17 may be replaced with an aperture stop for ring illumination (not shown). Here, as shown in fig. 5 (a), the diameter of, for example, a circular aperture of the aperture stop 17 is set to a maximum value, and the σ value is set to a maximum value NA1 (for example, about 0.8 to 0.9), so that large σ illumination is performed. In the case of performing large σ illumination, illumination light emitted from the emission end 14a of the optical fiber 10 must be collimated into a parallel light flux through the input lens 15 to illuminate the widest range (a range slightly wider than the region facing the maximum aperture of the aperture stop 17) of the incident surface of the fly eye lens 16. Therefore, the maximum inclination angle of the illumination light emitted from the emission end 14a must be set to the maximum value within the adjustable range.

Then, in step 104, the magnification of the variable magnification optical systems 8a to 8c, and further the maximum inclination angle of the illumination lights 3a to 3c of the light source images 9a to 9c formed on the incident ends 12a to 12c of the optical fiber 10 are adjusted based on the σ value set by the aperture stop 17. When the annular illumination aperture stop is used as the aperture stop 17, a value σ determined by the outer diameter of the annular aperture may be used as the value σ. Here, since the σ value is set to the maximum value NA1, the magnification of the variable magnification optical systems 8a to 8c is set to the minimum value within the variable magnification range, and the maximum inclination angle of the illumination lights 3a to 3c is set to the maximum value α 1 within the adjustable range. In fig. 5 (a), the focal length of the magnification-varying optical system 8a is set to f1, and the height of the light source image 9a is set to the minimum value y1 within the adjustable range.

In each of the optical fiber cores 11 constituting the optical fiber 10, the maximum tilt angle of the incident light beam is substantially equal to the maximum tilt angle of the emitted light beam. Therefore, when the aperture diameter of the aperture stop 17 is maximized, the illumination light 20a emitted from the emission end 14a of the optical fiber 10 is incident on the region of the incident surface of the fly eye lens 16 that can illuminate the maximum aperture via the input lens 15. The light intensity distribution (illuminance distribution) D1 of the light source image 9a formed at the incident end 12a is a substantially axisymmetric normal distribution, and the central portion is strong and the peripheral portion is sharply weak. When the height of the light source image 9a is the minimum value y1, the light intensity distribution D1 extends outside the incident surface of the incident end 12a with respect to the portion having the maximum value of about 10% or less, but most of the incident illumination light 3a (more precisely, the light flux obtained by randomly combining the incident illumination lights 3a to 3 c) is emitted from the emission end 14a or the like.

The light intensity distribution C31 of the illumination light 20a emitted from the emission end 14a on the incident surface of the fly eye lens 16 is a substantially axisymmetric distribution that becomes slightly stronger as it goes away from the optical axis and sharply weaker on the outside thereof. The light intensity distribution C31 is considered to be a substantially uniform value in a region facing the aperture of the aperture stop 17, and most of the illumination light 20a emitted from the emission end 14a at the maximum inclination angle α 1 enters the aperture of the aperture stop 17. Therefore, the ratio of the illumination light 20a that passes through the aperture of the aperture stop 17 and enters the mask M via the condenser lens 18 to the illumination light 3a that enters the optical fiber 10, that is, the utilization efficiency of the illumination light (hereinafter, also referred to as illumination efficiency) becomes high.

Then, in step 106, the light sources 2a to 2c are turned on, and the illumination device ILA illuminates the mask M with the illumination light 3a to 3c from the light sources 2a to 2c via the magnification-varying optical systems 8a to 8c, the optical fiber 10, the input lenses 15 of the local illumination optical systems IL1 to IL7, the fly-eye lens 16, the aperture stop 17, and the condenser lens 18. Next, in step 108, the plate material P is exposed by the projection optical system PL with a pattern image of the mask M, and the mask M and the plate material P are moved synchronously with respect to the projection optical system PL, thereby exposing the plate material P. At this time, since the mask M can be illuminated with high illumination efficiency using the illumination light of the maximum σ value, the pattern formed on the mask M can be exposed onto the plate material P with high productivity (productivity) and high accuracy.

Next, for example, when the pattern of the mask M to be exposed includes a fine isolated pattern such as a contact hole pattern, in order to perform so-called small σ illumination, in step 102, as shown in fig. 5 (B), the diameter of, for example, a circular aperture of the aperture stop 17 is set to a minimum value, and the σ value is set to a minimum value NA2 (for example, about 0.05 to 0.1). At this time, the illumination light emitted from the emission end 14a may be collimated into a light flux through the input lens 15 to illuminate the minimum region (a region slightly wider than the region facing the minimum aperture of the aperture stop 17) of the incident surface of the fly eye lens 16, and therefore the maximum inclination angle of the illumination light emitted from the emission end 14a may be set to the minimum value α 2 within the adjustable range. Therefore, in step 104, the magnification of the variable magnification optical systems 8a to 8c is set to the maximum value within the variable magnification range, and the maximum inclination angle of the illumination lights 3a to 3c is set to the minimum value α 2. In fig. 5 (B), the focal length of the magnification-varying optical system 8a is set to f2, and the height of the light source image 9a is set to the maximum value y 2.

The light intensity distribution D2 of the light source image 9a formed at the incident end 12a at this time is a substantially axisymmetric normal distribution in which the light intensity distribution D1 of fig. 5 (a) is enlarged by the magnification ratio y2/y 1. In the light intensity distribution D2, the portion having the maximum value of about 35% or less extends outside the incident surface of the incident end 12a, and about 60% of the incident illumination light 3a to 3c, for example, is emitted from the emission end 14a or the like. When the height y2 of the light source image 9a is set to be the interval of the portion where the light intensity is approximately 30% of the maximum value, the light source image 9a with the height y2 becomes slightly larger than the width of the incident end 12 a.

However, at this time, the maximum inclination angle of the illumination light 20a emitted from the emission end 14a is substantially the minimum value α 2, and most of the illumination light 20a enters the region facing the minimum aperture of the aperture stop 17 in the entrance surface of the fly eye lens 16 through the input lens 15. At this time, the light intensity distribution C11 of the illumination light 20a emitted from the emission end 14a on the incident surface of the fly eye lens 16 is a substantially axisymmetric distribution obtained by compressing the light intensity distribution C31 of fig. 5 (a) in the radial direction. The light intensity distribution C11 is considered to be a substantially uniform value in a region facing the minimum aperture of the aperture stop 17, and most of the illumination light 20a emitted from the emission end 14a at the maximum inclination angle of substantially α 2 enters the aperture of the aperture stop 17. Therefore, although the illumination light 3a incident to the incident end 12a generates a certain degree of light quantity loss, the utilization efficiency of the illumination light 20a that passes through the minimum aperture of the aperture stop 17 and is incident to the mask M via the condenser lens 18 with respect to the illumination light 3a is high. Subsequently, by performing

steps

106 and 108, for example, a pattern including an isolated pattern can be exposed onto the plate material P with high productivity and high accuracy.

Here, as a comparative example, the following is assumed: as shown in fig. 6a, the magnification of the magnification-varying optical system 8a is set to the minimum (the maximum inclination angle of the illumination light 3a is set to the maximum value α 1) and the σ value is set to the minimum value NA2 by the aperture stop 17, as in the case of fig. 5 a. In this comparative example, the light intensity distribution C31 of the illumination light 20a emitted from the emission end 14a on the incident surface of the fly eye lens 16 becomes considerably strong in the region 16Aa outside the region facing the minimum aperture of the aperture stop 17. Therefore, the illumination light 20a emitted from the emission end 14a has a light passing through the aperture of the aperture stop 17 of, for example, about 45%.

Therefore, the illumination efficiency of the illumination light 20a incident on the mask M when the magnification of the variable magnification optical system 8a is increased as in fig. 5 (B) of the present embodiment is improved by approximately 30% (about (60/45-1) · 100) compared to the comparative example in fig. 6 (a). In the present embodiment, 3 light sources 2a to 2c are used, but when the illumination efficiency is improved by, for example, 30%, only 2

light sources

2a and 2b can be turned on to perform exposure, and therefore the life of the light sources 2a to 2c can be extended.

Fig. 6 (B) shows the light intensity distributions D1 and D2 of the illumination light 3a at the incident end 12a of fig. 5 (a) and 5 (B) in terms of relative light intensities, and the horizontal axis of fig. 6 (B) shows the distance from the center of the incident end 12a with the center position thereof set to 0 in terms of relative values. As an example, the position where the horizontal axis has a value of 50 is the position of the edge portion of the incident end 12 a. In the case of the comparative example of fig. 6a, the light intensity distribution D3 of fig. 6B is a distribution in which the light intensity distribution D1 is compressed by the light quantity ratio of the illumination light passing through the aperture of the aperture stop 17 and the illumination light entering the fly eye lens 16. The light quantity obtained by integrating the light intensity distribution D2 at the inner side of the position ± 50 is the light quantity obtained in the present embodiment, and the light quantity obtained by integrating the light intensity distribution D3 is the light quantity obtained in the comparative example.

Fig. 6 (C) shows the light intensity distributions C31 and C11 of the illumination light 20a on the incident surface of the fly-eye lens 16 in fig. 5 (a) and 5 (B) with respect to the light intensity, and the horizontal axis of fig. 6 (C) shows the distance from the center with the center position of the incident surface set to 0 as a σ value. The relative intensities of the light intensity distributions C31, C11 were adjusted so that the values at 0.88 and 0.65 for σ became equal. At this time, when the values of the light intensity distributions C31 and C11 at the position where the σ value is 0.5 are taken as the average light intensity or the average illuminance, the average illuminances of the light intensity distributions C31 and C11 become approximately equal.

Next, when the σ value is set to an arbitrary value NA3 between the maximum value NA1 and the minimum value NA2 using the aperture stop 17 in step 102, the magnification of the variable magnification optical systems 8a to 8c may be set to a value β 3 between the minimum value (β 1) in fig. 5a and the maximum value (β 2) in fig. 5B in step 104. As an example, β 3 is set to be gradually larger as σ value NA3 gradually becomes smaller, and the maximum inclination angle of the illumination light incident on the optical fiber 10 is set to be gradually smaller, as expressed by the equation.

β3＝β1+(NA1-NA3)(β2-β1)/(NA1-NA2)…(2)

Accordingly, regardless of the σ value, the mask M can be illuminated with high illumination efficiency according to the σ value (illumination condition), and the pattern of the mask M can be exposed to the plate material P with high productivity and high accuracy.

Fig. 7 (a) is an enlarged view showing the local illumination optical system IL1 of fig. 5 (a), fig. 7 (B) is an enlarged view showing the emission end 14a of the optical fiber 10 of fig. 7 (a) as viewed from the front, and fig. 7 (a) is an enlarged view showing lens units 16a having the same shape as a part of the fly-eye lens 16. As shown in fig. 7 (B), the emission end 14a is formed by regularly bundling a large number of optical fiber cores 11. In fig. 7a, the emission end 14a forms an image on an emission surface (a so-called pupil surface, which is a surface on which the aperture stop 17 is disposed) of the lens unit 16a via the input lens 15 and the lens unit 16 a. Since the incident surface of the lens unit 16a forms an image on the illumination region 21a of the mask M through the lens unit 16a and the condenser lens 18, the shape of each lens unit 16a of the fly-eye lens 16 is determined such that the illumination region 21a is slightly larger than the exposure field (the region conjugate to the aperture of the field stop 22 in fig. 3).

The light intensity distribution at the incident end 12a of the optical fiber 10 is changed by the variable power optical system 8 a. Here, as an example, a light source image formed on the arrangement surface of the aperture stop 17 via the input lens 15 and the fly eye lens 16 by light emitted from the optical fiber core 11 into which light having a light intensity of about 10% of the maximum light intensity at the time of large σ illumination enters is regarded as an effective light source image contributing to illumination. When the light emitted from all the optical fiber cores 11 at the emission end 14a forms effective light source images, the number n1 of the effective light source images formed on the emission surface of the lens unit 16a of the fly-eye lens 16 located in the range where the light is incident is the same as the number n2 of the optical fiber cores 11 constituting the emission end 14 a.

Hereinafter, the ratio of the number n1 of effective light source images formed on the emission surface of the lens unit 16a to the number n2 of the optical fiber cores 11 constituting the emission end 14a (n 1/n2) is referred to as a filling factor γ of the illumination light from the optical fiber cores 11 in the lens unit 16 a. In the present embodiment, as an example, the magnification of the variable magnification optical system 8a (the maximum inclination angle of the illumination light incident on the incident end 12 a) is adjusted so that the filling factor γ is maintained at 1 (100%).

At this time, when the ring illumination, the large σ illumination, or the small σ illumination is performed, the effective light source image 24 is formed with the same maximum density distribution (distribution corresponding to the density distribution of the optical fiber core wires 11 in fig. 7B) as shown in fig. 8a, 8B, or 8C on the emission surface of the lens unit 16a of the fly-eye lens 16 located in the aperture of the aperture stop 17, respectively. In fig. 8 (a), the aperture of the aperture stop 17 is set to an annular aperture 17 c. In the case of ring illumination or large σ illumination, the maximum inclination angle of illumination light incident from the variable magnification optical systems 8a to 8c to the incident ends 12a to 12c of the optical fiber 10 is set larger than that in the case of small σ illumination.

For convenience of explanation, each lens unit 16a of the fly-eye lens 16 is shown larger than the actual aperture 17B, 17C in fig. 8 (a) to 8 (C) and fig. 9 (a) and 9 (B) described later.

In this way, in the present embodiment, the magnification of the variable magnification optical system 8a is adjusted within a range in which the fill factor γ of the illumination light from the optical fiber 11 is 1 when the ring illumination, the large σ illumination, or the small σ illumination is performed. At this time, the number of effective light source images 14 in the aperture of the aperture stop 17 is the largest, and therefore the uniformity of the illuminance distribution on the mask M is good. The filling rate γ may be substantially 1 (for example, 0.9 to 1).

However, the light intensity of the illumination light incident on the incident ends 12a to 12c of the optical fiber 10 is maximum at the center portion and becomes smaller toward the periphery. Therefore, light source images formed by illumination light from the optical fiber core wires 11 on which the illumination light 3a having a light intensity with a maximum value of, for example, about 70% or more, about 70 to 40% or about 40 to 10% in the large σ illumination is incident, among a large number of optical fiber core wires 11 constituting the incident end 12a, are referred to as light source images 24A, 24B, and 24C, respectively. At this time, when the σ value is set large as shown in fig. 5 (a), light source images 24A, 24B, and 24C are formed in a random arrangement on the emission surface of the lens unit 16a in the aperture 17B of the aperture stop 17 among the emission surfaces of the fly-eye lens 16 as shown in fig. 9 (a).

The illumination light emitted from the emission end 14a of the optical fiber 10 is distributed in a region wider than the size of the entrance port (the entrance surface of the plurality of lens units 16a located in the large aperture 17 b) of the plurality of lens units 16a (optical elements) of the fly eye lens 16.

On the other hand, when the σ value is set to be small as shown in fig. 5 (B), a light source image 24B having a substantially medium light intensity is formed in a regular arrangement on the emission surface of the lens unit 16a in the aperture 17B of the aperture stop 17 among the emission surfaces of the fly eye lens 16 as shown in fig. 9 (B). The illumination light emitted from the emission end 14a of the optical fiber 10 is distributed over a region wider than the size of the entrance port of the plurality of lens units 16a of the fly-eye lens 16 located in the small aperture 17 b. Therefore, in the case of small σ illumination, the light intensity of the light source image 24B formed on the emission surface of each lens unit 16a of the fly-eye lens 16 is more uniform than in the case of fig. 9 (a), and therefore the illuminance distribution is more uniform.

When the small σ illumination of the numerical aperture NA2 is performed as in the comparative example, if the aperture 17b of the aperture stop 17 is simply reduced as shown by the broken line in fig. 9 (a), most of the illumination light entering from the optical fiber 10 to the outside of the aperture 17b is blocked, and therefore, the utilization efficiency of the illumination light is lowered.

As described above, the illumination device ILA for illuminating the mask M according to the present embodiment includes: a light source 2a that generates illumination light; a variable magnification optical system 8a that adjusts the maximum tilt angle of the illumination light in step 104; an input lens 15 (hereinafter also referred to as a1 st condensing optical system) for condensing the illumination light passed through the variable magnification optical system 8a into a parallel light flux in step 106; an optical fiber 10 (hereinafter also referred to as an optical member) that emits the illumination light via the magnification-varying optical system 8a to the input lens 15 while maintaining the maximum inclination angle of the illumination light in step 106; an aperture stop 17 for adjusting the numerical aperture (σ value) of the illumination light in step 102; and a condenser lens 18 (hereinafter also referred to as a2 nd condensing optical system) for guiding the illumination light whose numerical aperture is controlled to the mask M in step 106.

According to the illumination device ILA of the present embodiment, when performing small σ illumination for reducing the numerical aperture of illumination light, the maximum inclination angle of the illumination light is reduced by the magnification-varying optical system 8a, whereby the proportion of illumination light incident on the aperture of the aperture stop 17 can be increased, and the utilization efficiency of illumination light can be improved. Therefore, the mask M can be illuminated with a greater illuminance. Further, when the mask M is illuminated with the same illuminance, the lifetime of the light source 2a can be extended, and when a plurality of light sources 2a to 2c are used, the number of light sources used can be reduced, thereby achieving downsizing and cost reduction of the illumination device ILA. Further, since the optical fiber 10 is used, the light source 2a can be separated from the mask M, and thermal expansion of the mask M can be suppressed.

The exposure apparatus EX of the present embodiment, which exposes the pattern of the mask M to the plate material P, includes: an illumination device ILA that illuminates the mask M in steps 102 to 106; and a projection optical system PL that forms an image of the pattern of the mask M illuminated by the illumination device ILA onto the sheet material P in step 108. According to the exposure apparatus EX, since the utilization efficiency of the illumination light in the illumination apparatus ILA is high, the pattern of the mask M can be exposed onto the plate material P with high productivity and high accuracy by increasing the illuminance of the illumination light. In addition, when the illuminance of the illumination light is the same as that of the conventional one, the illumination apparatus ILA can be made smaller and lower in cost, and therefore the exposure apparatus EX can be made further smaller and lower in cost.

Further, since the optical fiber 10 includes the plurality of incident ends 12a to 12c and the plurality of output ends 14a and 14b, the illumination light from the plurality of light sources 2a to 2c can be mixed at random and easily branched into the light fluxes for the plurality of local illumination optical systems IL1 to IL 7.

Further, since the fly-eye lens 16 including the plurality of lens units 16a is provided, the illuminance distribution of the illumination light in the illumination region of the mask M can be made more uniform.

In the above embodiment, the following modifications are possible.

As the variable power optical system 8a of the above embodiment, a variable power optical system 8Aa can be used, and as shown in fig. 10 (a), the variable power optical system 8Aa includes a front group lens system 6A including 3 lenses and a rear group lens system 7A including 3 lenses, and the position of the rear group lens system 7A is adjusted, for example, at the time of magnification adjustment.

Further, as the variable magnification optical system 8a, an optical system of a type that forms an intermediate image of the light source image on the optical path between the light source image 5a and the light source image 9a can be used.

Further, in the above-described embodiment, the magnification-varying optical system 8a is used to control the maximum inclination angle of the illumination light, but instead of the magnification-varying optical system 8a, a relay optical system 8Ba may be used in which the magnification is switched by partially replacing the optical system, as shown in fig. 10 (B). The relay optical system 8Ba has: a front group lens system 6A; a1 st rear group lens system 7B including a lens 7Ba and a lens group 7Bb having 2 lenses; and a2 nd rear group lens system 7C including lenses 7Ca and 7 Cb. When the magnification is low, the light source image 9a is formed using the front group lens system 6A and the 1 st rear group lens system 7B, and when the magnification is high, the light source image 9a is formed using the 2 nd rear group lens system 7C instead of the 1 st rear group lens system 7B. In this way, when the interchangeable relay optical system 8Ba is used, an optical system for controlling the tilt angle can be manufactured at low cost.

Further, in the variable power optical system 8a of the above embodiment, for example, an optical system (axicon system) including 2 conical prism-shaped optical members 7B1 and 7B2 as shown by a broken line in fig. 10 a as disclosed in U.S. patent No. 5,719,704 may be provided between the front group lens system 6 and the rear group lens system 7. In this case, the following steps are also possible: in the case of normal illumination, the 2 optical members 7B1 and 7B2 are brought into close contact, and in the case of ring illumination, the interval between the 2 optical members 7B1 and 7B2 is adjusted so that the cross-sectional shape of the illumination light 3a passing between the front group lens system 6 and the rear group lens system 7 is a ring shape with a variable size. At this time, the illumination light 20a emitted from the emission end 14a of the optical fiber 10 is incident on the annular region of the incident surface of the fly eye lens 16 via the input lens 15. In addition, when ring illumination is performed, the interval between the 2 optical members 7B1 and 7B2 is adjusted according to the size of the ring aperture of the aperture stop, and thus the utilization efficiency of illumination light when ring illumination is performed can be further improved.

Further, although the fly-eye lens 16 is used as the optical integrator in the above embodiment, a microlens array, an optical integrator rod, or the like may be used instead of the fly-eye lens 16.

In the above embodiment, an ultra-high pressure mercury lamp is used as the light sources 2a to 2c, but any other lamp such as a discharge lamp can be used as the light sources 2a to 2 c. Light Emitting Diodes (LEDs) and the like may be used as the light sources 2a to 2 c. As the light sources 2a to 2c, laser light sources such as solid-state lasers, gas lasers, and semiconductor lasers may be used. Further, as the illumination light, a harmonic of laser light or the like may be used.

When a laser light source is used as the light source and the maximum inclination angle of the illumination light is set to be large, as an example, as shown in fig. 10C, a diffraction grating 8C is disposed on the optical path of a laser beam LB including a parallel light flux generated from the laser light source (not shown), and the diffraction grating 8C is formed with concentric circle-shaped (zone-plate-shaped) phase-type irregularities having a fine pitch that gradually decreases. The minimum pitch of the diffraction grating 8C is specified according to the maximum tilt angle.

When the maximum inclination angle of the illumination light is set small by using the laser light source, a diffraction grating 8D is disposed on the optical path of the laser beam LB, and the diffraction grating 8D is formed with concentric phase-type irregularities similar to the diffraction grating 8C, and has a smaller minimum pitch than the diffraction grating 8C. In this modification, since illumination light with a large maximum inclination angle can be generated when the diffraction grating 8C is used, and illumination light with a small maximum inclination angle can be generated when the diffraction grating 8D is used, the same effects as those of the above-described embodiment can be obtained.

In addition, although the above-described embodiment has been described by taking a scanning exposure apparatus of a multi-lens type as an example, the above-described embodiment can be applied to a step-and-repeat type exposure apparatus that exposes the pattern of the mask M while the mask M and the plate material P are stationary and sequentially moves the plate material P in steps, in addition to the scanning exposure apparatus. Further, 3 light sources are used as the light sources of the illumination device, but the illumination device may be provided with 1, 2, or 4 or more light sources. In the above embodiment, the optical fiber has 7 emission ends, but the number of emission ends of the optical fiber may be any number as long as the number is 1 or more.

Further, in the above-described embodiment, the illumination light from the plurality of light sources 2a to 2c is branched into the light fluxes for the plurality of local illumination optical systems IL1 to IL7, but the mask M may be illuminated via one local illumination optical system IL1 by the illumination light from one light source 2a, and the pattern of the mask M may be transferred to the plate material P via one imaging optical system (for example, an optical system similar to the local projection optical system PL 1). At this time, the illumination light 3a from the magnification-varying optical system 8a may be directly incident on the fly-eye lens 16 via the input lens 15 without providing the optical fiber 10.

Next, a device manufacturing method using the exposure apparatus or the exposure method according to the above embodiment will be described. Fig. 11 is a flowchart showing a process for manufacturing a liquid crystal device such as a liquid crystal display device. As shown in fig. 11, in the manufacturing process of the liquid crystal element, a pattern forming process (step 200), a color filter forming process (step 202), a cell assembling process (step 204), and a module assembling process (step 206) are sequentially performed.

In the pattern forming step of step 200, a predetermined pattern such as a circuit pattern or an electrode pattern is formed on a glass substrate coated with a photoresist as a plate material by using the above-described exposure apparatus or exposure method. The pattern forming process includes: an exposure step of transferring a pattern onto the photoresist layer using the exposure apparatus or the exposure method according to the above embodiment; a developing step of developing the plate material to which the pattern is transferred to generate a photoresist layer having a shape corresponding to the pattern as a mask layer; and a processing step of processing the surface of the glass substrate through the developed photoresist layer.

In the color filter forming step of step 202, a color filter is formed in which a large number of groups of 3 dots corresponding to R (red), G (green), and B (blue) or a plurality of groups of 3 filters of R, G, B are arranged in the horizontal scanning direction in a matrix.

In the cell mounting step of step 204, a liquid crystal panel (liquid crystal cell) is mounted using the glass substrate on which the predetermined pattern is formed in step 200 and the color filter formed in step 202. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter.

In the module mounting step of step 206, various components such as electronic circuits and backlight for performing display operation of the liquid crystal panel are mounted on the liquid crystal panel mounted in step 204. As described above, the element manufacturing method of the present embodiment includes: forming a predetermined pattern on a glass substrate by using the exposure apparatus EX or the exposure method of the above embodiment; and processing the glass substrate through the predetermined pattern. According to the exposure apparatus EX or the exposure method of the present embodiment, since exposure can be performed with high illumination efficiency, electronic components can be manufactured with high productivity and high accuracy.

The exposure apparatus EX and the exposure method according to the above embodiments can be applied to the manufacture of semiconductor devices. The above-described embodiments are not limited to the application to exposure apparatuses for manufacturing semiconductor devices or liquid crystal devices, and can be widely applied to exposure apparatuses for display devices such as plasma displays, or exposure apparatuses for manufacturing various devices such as image sensors (CCD, etc.), micromachines, thin film magnetic heads, and DNA chips. Further, the above embodiments can be applied to an exposure apparatus for manufacturing a mask (a photomask, a reticle, or the like) used for manufacturing various devices by using a photolithography process.

Description of the symbols

2a, 2b, 2 c: light source

4a, 4b, 4 c: elliptical mirror

8a to 8 c: variable magnification optical system

10: optical fiber

12a, 12b, 12 c: incident end

14a, 14 b: injection end

15: input lens

16: fly-eye lens

17: aperture diaphragm

18: condensing lens

30: control unit

32: power supply device

EX: exposure device

ILA: lighting device

IL1, IL 3: local illumination optical system

PL: projection optical system

PL 1-PL 7: partial projection optical system

M: mask and method for manufacturing the same

P: sheet material

Claims

1. An illumination apparatus that illuminates a mask, comprising:

a light source generating illumination light;

an optical system that adjusts a tilt angle of the illumination light;

a1 st condensing optical system that condenses the illumination light passed through the optical system;

an optical member that emits the illumination light via the optical system to the 1 st condensing optical system while maintaining the inclination angle of the illumination light;

an aperture stop that adjusts a numerical aperture of the illumination light emitted from the 1 st condensing optical system; and

a2 nd condensing optical system that guides the illumination light whose numerical aperture is adjusted to the mask,

the optical member branches the illumination light via the optical system into a plurality of light beams maintaining the inclination angle of the illumination light,

a plurality of sets of the 1 st condensing optical system, the aperture stop, and the 2 nd condensing optical system are provided corresponding to the plurality of light fluxes branched by the optical member,

illuminating a plurality of illumination areas of the mask.

2. The lighting device of claim 1,

the 1 st condensing optical system includes an optical element group including a plurality of optical elements for uniformizing the illuminance distribution of the illumination light,

the illumination light passing through the optical member is distributed over a region wider than the size of the entrance port of the optical element of the 1 st condensing optical system.

3. The lighting device of claim 1,

the optical system adjusts the tilt angle of the illumination light based on a numerical aperture of the aperture stop.

4. A lighting device as recited in claim 3,

the optical system reduces the inclination angle of the illumination light when the numerical aperture is reduced using the aperture stop.

5. A lighting device as recited in claim 3,

when the aperture stop is used to increase the numerical aperture or the aperture of the aperture stop is formed in an annular shape, the optical system increases the inclination angle of the illumination light.

6. A lighting device as recited in any one of claims 1-5,

the optical system is a variable magnification optical system that forms an image with a variable magnification of the light source.

7. The lighting device of claim 6,

when the aperture stop is used to reduce the numerical aperture, the magnification of the image of the light source is increased by the variable magnification optical system.

8. The lighting device of claim 6,

the variable magnification optical system reduces the magnification of the image of the light source when the aperture stop is used to increase the numerical aperture or when the aperture of the aperture stop is in the shape of a ring.

9. The lighting device of claim 1,

the optical member has a plurality of incident ends,

the optical member includes a plurality of sets of the light source and the optical system corresponding to the plurality of incident ends of the optical member.

10. A lighting device as recited in any one of claims 1-5,

the illumination distribution of the image of the light source is in a normal distribution shape.

11. The lighting device of claim 2,

the optical member is formed by bundling a plurality of optical fiber cores,

the numerical aperture of the illumination light is adjusted by the aperture stop under the condition that the number of the optical fiber cores constituting the emission ends of the optical member is substantially equal to the number of light source images formed at the emission ends of the plurality of optical elements of the optical element group.

12. An exposure apparatus that exposes a pattern of a mask onto a substrate, comprising:

the lighting device of any one of claims 1 to 5; and

and a projection optical system that forms an image of the pattern of the mask illuminated by the illumination device onto a substrate.

13. The exposure apparatus according to claim 12,

the illumination device illuminates a plurality of illumination areas of the mask,

a plurality of the projection optical systems are provided corresponding to the plurality of illumination regions,

the exposure apparatus includes a stage device that scans the mask and the substrate relatively in a direction intersecting with an arrangement direction of the plurality of illumination regions.

14. A method of illuminating a mask, comprising:

adjusting an inclination angle of illumination light generated from a light source;

emitting the illumination light of which the inclination angle is adjusted through an optical member that maintains the inclination angle of the illumination light;

condensing the emitted illumination light;

adjusting a numerical aperture of the illumination light; and

directing the illumination light with the adjusted numerical aperture to the mask,

branching the illumination light of which the inclination angle is adjusted into a plurality of light beams using the optical member,

illuminating a plurality of illumination areas of the mask using the plurality of light beams.

15. The lighting method according to claim 14,

condensing the illumination light includes uniformizing an illuminance distribution of the illumination light using an optical element group including a plurality of optical elements,

the illumination light passing through the optical member is distributed over a region wider than the size of the entrance port of the plurality of optical elements.

16. The lighting method according to claim 14,

adjusting the tilt angle of the illumination light includes adjusting the tilt angle of the illumination light based on a numerical aperture of the illumination light.

17. The lighting method according to claim 16,

reducing the tilt angle of the illumination light when reducing the numerical aperture of the illumination light.

18. The lighting method according to claim 16,

adjusting the numerical aperture of the illumination light includes ring illuminating using the illumination light,

when the numerical aperture of the illumination light is enlarged or ring illumination is performed using the illumination light, the tilt angle of the illumination light is enlarged.

19. The lighting method according to any one of claims 14 to 18,

adjusting the tilt angle of the illumination light includes forming a variable magnification image of the light source.

20. The lighting method according to claim 19,

when the numerical aperture of the illumination light is reduced, the magnification of the image of the light source is increased.

21. The lighting method according to claim 19,

when the numerical aperture of the illumination light is increased or ring illumination is performed using the illumination light, the magnification of the image of the light source is reduced.

22. The lighting method according to claim 14,

the optical member has a plurality of incident ends,

the lighting method comprises the following steps: the illumination light from the plurality of light sources is incident on the plurality of incident ends by adjusting the inclination angle, respectively.

23. The lighting method according to claim 15,

the optical member is configured by bundling a plurality of optical fiber cores,

the numerical aperture of the illumination light is adjusted under the condition that the number of the optical fiber cores constituting the emission ends of the optical member is substantially equal to the number of light source images formed at the emission ends of the plurality of optical elements of the optical element group.

24. An exposure method of exposing a pattern of a mask onto a substrate, comprising:

illuminating the mask using the illumination method of any one of claims 14 to 18; and

forming an image of the illuminated pattern of the mask onto a substrate.

25. The exposure method according to claim 24,

the illumination method includes illuminating a plurality of illumination regions of the mask,

the exposure method comprises the following steps:

forming images of the patterns of the mask of the plurality of illumination areas onto the substrate, respectively; and

the mask and the substrate are relatively scanned in a direction crossing an arrangement direction of the plurality of illumination regions.

26. A method for manufacturing a device, comprising:

forming a predetermined pattern on a substrate using the exposure apparatus according to claim 12 or 13; and

processing the substrate through the predetermined pattern.

27. A method for manufacturing a device, comprising:

forming a predetermined pattern on a substrate by using the exposure method according to claim 24 or 25; and

processing the substrate through the predetermined pattern.