WO2004112107A1

WO2004112107A1 - Lighting optical device, exposure system and exposure method

Info

Publication number: WO2004112107A1
Application number: PCT/JP2004/008096
Authority: WO
Inventors: Hisashi Nishinaga; Yuji Kudo
Original assignee: Nikon Corporation
Priority date: 2003-06-16
Filing date: 2004-06-10
Publication date: 2004-12-23
Also published as: JPWO2004112107A1; TW200508812A

Abstract

A lighting optical device capable of appropriately adjusting the aspect ratio of a secondary light source formed in a lighting pupil based on a simple constitution. A lighting optical device for illuminating a surface to be illuminated (M) based on light fluxes from a light source (1). The device is provided with aspect ratio changing means (8, 9) for changing the aspect ratio of a light intensity distribution formed in a lighting pupil which is substantially in Fourier transform relation with a surface to be illuminated. The aspect ratio changing means are provided with optical element groups (8a, 8b, 9a, 9b) disposed in positions or in the vicinities thereof which are substantially in Fourier transform relation with a lighting pupil and having the function of changing a power ratio between two orthogonal directions.

Description

Specification

Illumination optical device, exposure apparatus, and exposure method

Technical field

The present invention relates to an illumination optical device, an exposure device, and an exposure method, and is particularly suitable for an exposure device for manufacturing a micro device such as a semiconductor device, an imaging device, a liquid crystal display device, and a thin-film magnetic head by a lithography process. The present invention relates to an illumination optical device.

^ Scenic technology

[0002] In a typical exposure apparatus of this type, a light beam emitted from a light source enters a micro fly's eye lens (or a fly's eye lens), and a secondary light source including a large number of light sources is provided on a rear focal plane. Form. The luminous flux from the secondary light source is restricted via an aperture stop arranged near the rear focal plane of the micro fly's eye lens if necessary, and then enters the condenser lens.

[0003] The light beam condensed by the condenser lens illuminates the mask on which a predetermined pattern is formed in a superimposed manner. The light transmitted through the mask pattern forms an image on the wafer via the projection optical system. Thus, the mask pattern is projected and exposed (transferred) on the wafer. Since the pattern formed on the mask is highly integrated, it is essential to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

[0004] In recent years, by changing the size of a secondary light source formed on an illumination pupil through a micro fly's eye lens, coherency σ of illumination (σ value = aperture stop diameter / projection optical system Attention has been focused on a technology that changes the pupil diameter or σ value = exit-side numerical aperture of the illumination optical system 入射 entrance-side numerical aperture of the projection optical system. Also, attention has been focused on a technology that improves the depth of focus and resolution of the projection optical system by forming an annular or quadrupolar secondary light source on the illumination pupil through a micro fly's eye lens.

Disclosure of the invention

Problems the invention is trying to solve

[0005] In the related art, for example, when performing annular illumination based on an annular secondary light source, the secondary light When the source is formed in a slightly vertical or horizontal ring shape, the line width of the pattern transferred onto the wafer differs between the vertical and horizontal directions, that is, the line width of the pattern in two orthogonal directions. Differences may occur. Further, even if the secondary light source is formed in a desired annular shape, there is a force S that a line width difference of a pattern occurs in two orthogonal directions due to resist characteristics and the like. If the pattern to be transferred has directionality, it may be desirable to actively set the annular secondary light source formed on the illumination pupil to be vertically or horizontally long.

[0006] The present invention has been made in view of the above-described problems, and provides an illumination optical device that can adjust the aspect ratio of a secondary light source formed on an illumination pupil at any time based on a simple configuration. The purpose is to do. In addition, by using an illumination optical device that can adjust the aspect ratio of a secondary light source formed on the illumination pupil at any time, a high-precision pattern in which a line width difference of a pattern does not substantially occur in two orthogonal directions. An object is to provide an exposure apparatus and an exposure method capable of performing exposure.

Means for solving the problem

[0007] In order to solve the above-described problems, according to a first embodiment of the present invention, there is provided an illumination optical device that illuminates an irradiation surface based on a light beam from a light source,

An aspect ratio changing unit for changing an aspect ratio of a light intensity distribution formed on an illumination pupil substantially in a Fourier transform relationship with the irradiated surface,

The aspect ratio changing means is an optical element group disposed at or near a position substantially in Fourier transform relationship with the illumination pupil and having a function of changing a power ratio in two orthogonal directions. An illumination optical device is provided.

[0008] According to a preferred mode of the first mode, the optical element group includes a first optical element group having different powers in two orthogonal directions and a second optical element having different powers in two orthogonal directions. And at least one of the first optical element group and the second optical element group is configured to be rotatable about an optical axis. Further, it is preferable that both the first optical element group and the second optical element group are configured to be rotatable around the optical axis. Preferably, the optical element group is a lens group.

In the first embodiment, the first optical element group and the second optical element group are It is preferable that a pair of optical elements having rotationally asymmetric power be provided, and it is more preferable that a pair of cylindrical lenses be provided. The above-mentioned rotationally asymmetric power means a power which is rotationally asymmetrical with respect to the optical axis of an optical element having a rotationally asymmetrical power.

[0010] Further, in the first embodiment, it is preferable that the optical element group further includes a changing unit that continuously changes a size of a light intensity distribution formed in the illumination pupil. It is preferable that the light source is disposed in an optical path closer to the light source than the changing unit. Here, the changing unit changes the size of the outer shape of the light intensity distribution formed on the illumination pupil, and changes the annular ratio of the light intensity distribution formed on the illumination pupil. It is preferable to include the second changing means.

According to a second embodiment of the present invention, there is provided an illumination optical device for illuminating a surface to be illuminated based on a light beam from a light source,

A light beam conversion element for converting a light beam from the light source into a light beam having a predetermined cross section;

A forming optical system for forming a predetermined light intensity distribution on an illumination pupil substantially in a Fourier transform relationship with the irradiated surface based on the light beam from the light beam conversion element; Aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil by independently changing the degree of divergence of the light beam in two orthogonal directions. An illumination optical device is provided.

According to a preferred mode of the second aspect, the aspect ratio changing means has a first optical element having different degrees of divergence in two orthogonal directions, and a different degree of divergence in two orthogonal directions. A second optical element, and at least one of the first optical element and the second optical element is configured to be rotatable about an axis parallel to a traveling direction of the light beam. Further, it is preferable that both the first optical element and the second optical element are configured to be rotatable around an axis parallel to a traveling direction of the light beam. Preferably, an axis parallel to the traveling direction of the light beam is an optical axis.

According to a preferred mode of the second mode, the first optical element and the second optical element each include a diffractive optical element having a diverging function only in one direction. Alternatively, Preferably, the first optical element and the second optical element each have a Fresnel lens having a refraction function only in one direction. Alternatively, it is preferable that each of the first optical element and the second optical element has a microlens array having a refractive function only in one direction. Further, it is preferable that the forming optical system has an optical integrator.

According to a third embodiment of the present invention, there is provided an illumination optical device for illuminating an irradiation surface based on a light beam from a light source,

A forming optical system for forming a predetermined light intensity distribution on an illumination pupil that is substantially in a Fourier transform relationship with the surface to be illuminated based on the light beam from the light beam converting element; the light source and the light beam converting element And an aspect ratio changing means for changing an aspect ratio of a light intensity distribution formed on the illumination pupil by independently changing power in two orthogonal directions. An illumination optical device characterized by comprising:

[0015] According to a preferred mode of the third mode, the aspect ratio changing means includes a cylindrical zoom lens rotatable around an optical axis. Alternatively, the aspect ratio changing means includes a first cylindrical zoom lens having a function of changing power in one of the two orthogonal directions, and a power in the other direction of the two orthogonal directions. It is preferable to include a second cylindrical zoom lens having a function of changing the position. It is preferable that the forming optical system has an optical integrator.

According to a fourth aspect of the present invention, there is provided an exposure apparatus for transferring a pattern of a mask onto a photosensitive substrate, wherein the illumination optical apparatus according to the first aspect and the third aspect includes the illumination optical device according to the first aspect and the third aspect. And a projection optical system for projecting a mask pattern onto the photosensitive substrate.

According to a fifth aspect of the present invention, in an exposure method for transferring a mask pattern onto a photosensitive substrate, the illumination optical device according to the first to third aspects is used to set the pattern on the surface to be irradiated. There is provided an exposure method, comprising a step of illuminating the mask and a step of projecting and exposing a pattern of the mask onto the photosensitive substrate.

The invention's effect

In the illumination optical device according to a typical aspect of the present invention, the operation of the aspect ratio changing means including the first cylindrical lens pair and the second cylindrical lens pair allows the illumination pupil to be formed based on a simple configuration. The aspect ratio of the formed secondary light source can be adjusted at any time. Therefore, in the exposure apparatus and the exposure method of the present invention, an illumination optical apparatus capable of adjusting the aspect ratio of a secondary light source formed on an illumination pupil at any time is used, and a line of a pattern is formed in two orthogonal directions. High-precision exposure with substantially no width difference can be performed, and a good microdevice can be manufactured by high-precision exposure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a view schematically showing a configuration of a conical axicon system arranged in an optical path between a front lens group and a rear lens group of an afocal lens in the first embodiment.

FIG. 3 is a view for explaining the action of a cone system on a secondary light source formed in the annular illumination of the first embodiment.

FIG. 4 is a diagram showing a shift with respect to a secondary light source formed in the annular illumination of the first embodiment.

FIG.

FIG. 5 is a view schematically showing a configuration of a first cylindrical lens pair and a second cylindrical lens arranged in an optical path between a front lens group and a rear lens group of an afocal lens in the first embodiment. is there.

FIG. 6 is a view for explaining the action of the first cylindrical lens pair and the second cylindrical lens pair on the secondary light source formed in the annular illumination of the first embodiment.

FIG. 7 is a view for explaining the action of a first cylindrical lens pair and a second cylindrical lens pair on a secondary light source formed in the annular illumination of the first embodiment.

FIG. 8 is a view for explaining the action of the first cylindrical lens pair and the second cylindrical lens pair on the secondary light source formed in the annular illumination of the first embodiment.

FIG. 9 is a view schematically showing a configuration of an exposure apparatus according to a second embodiment of the present invention. FIG. 10 is a diagram schematically showing a configuration of an aspect ratio changing unit according to a second embodiment.

FIG. 11 is a diagram illustrating the action of a pair of Fresnel lenses on a secondary light source formed in the annular illumination of the second embodiment.

FIG. 12 is a view schematically showing a configuration of an exposure apparatus according to a third embodiment of the present invention.

FIG. 13 is a diagram schematically showing an internal configuration of an aspect ratio changing unit according to a third embodiment.

FIG. 14 is a view for explaining the action of a cylindrical zoom lens on a secondary light source formed in a third embodiment.

FIG. 15 is a diagram showing a light intensity distribution obtained at an illumination pupil in a true circular state and an elliptical state of the cylindrical zoom lens.

FIG. 16 is a view schematically showing an internal configuration of an aspect ratio changing means according to a modification of the third embodiment.

FIG. 17 is a flowchart of a method for obtaining a semiconductor device as a micro device.

FIG. 18 is a flowchart of a method for obtaining a liquid crystal display element as a micro device. BEST MODE FOR CARRYING OUT THE INVENTION

An embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to a first embodiment of the present invention. In FIG. 1, the Z axis is along the normal direction of the wafer that is a photosensitive substrate, the Y axis is in the direction parallel to the plane of FIG. 1 in the plane of the wafer, and the Y axis is perpendicular to the plane of FIG. 1 in the plane of the wafer. The X axis is set in each direction. In FIG. 1, the illumination optical device is set to perform annular illumination.

The exposure apparatus shown in FIG. 1 uses, for example, a KrF excimer laser light source for supplying light having a wavelength of ¾48 nm or an ArF excimer laser for supplying light having a wavelength of 193 nm as a light source 1 for supplying exposure light (illumination light). It has a light source. A substantially parallel light beam emitted from the light source 1 along the Z direction has a rectangular cross section elongated in the X direction and enters a beam expander 2 including a pair of lenses 2a and 2b. Each lens 2a and 2b Has a negative refractive power and a positive refractive power in the plane of FIG. 1 (in the YZ plane). Therefore, the light beam incident on the beam expander 2 is enlarged in the plane of FIG. 1 and shaped into a light beam having a predetermined rectangular cross section.

A substantially parallel light beam passing through a beam expander 2 as a shaping optical system is deflected in the Υ direction by a bending mirror 3, and then enters a diffractive optical element (DOE) 4a for annular illumination. Generally, a diffractive optical element is formed by forming a step having a pitch of about the wavelength of exposure light (illumination light) on a glass substrate, and has a function of diffracting an incident beam to a desired angle. The diffractive optical element 4a has a function of forming, for example, a ring-shaped light intensity distribution in the far field (Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section enters, for example. .

The orbicular zone illumination diffractive optical element 4a is configured to be freely detachable from the illumination optical path, and is configured to be switchable with, for example, a circular illumination diffractive optical element 4b. The configuration and operation of the diffractive optical element 4b for circular illumination will be described later. Here, switching between the diffraction optical element 4a for annular illumination and the diffractive optical element 4b for circular illumination is performed by a drive system 22 that operates based on a command from the control system 21. Information about various masks to be sequentially exposed according to the step-and-repeat method or the step-and-scan method is input to the control system 21 via the input means 20 such as a keyboard.

The light beam passing through the diffractive optical element 4a as a light beam conversion element enters an afocal lens (relay optical system) 5. The afocal lens 5 is set such that the front focal position thereof substantially matches the position of the diffractive optical element 4a, and the rear focal position substantially matches the position of the predetermined surface 6 indicated by a broken line in the figure. It is an afocal system (a non-focus optical system). Therefore, the substantially parallel light beam that has entered the diffractive optical element 4a forms an orbicular light intensity distribution on the pupil plane of the afocal lens 5, and then emerges from the afocal lens 5 as a substantially parallel light beam.

[0025] In the optical path between the front lens group 5a and the rear lens group 5b of the afocal lens 5, at or near the pupil, in order from the light source side, a conical axicon as a second changing means is provided. System 7, the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 The force S, its detailed configuration and operation will be described later. Hereinafter, for the sake of simplicity, the basic configuration and operation of the first embodiment will be described ignoring the operation of the conical axicon system 7, the first pair of cylindrical lenses 8, and the second pair of cylindrical lenses 9. I do.

The light beam passing through the afocal lens 5 is incident on a micro flywheel lens 11 as an optical integrator via a zoom lens (variable optical system) 10 for changing a value as a first changing unit. Note that the σ value is the size (diameter) of the secondary light source formed on the pupil (illumination pupil) of the illumination optical system, and the size of the illumination light flux or light source image formed on the pupil of the projection optical system PL. When the diameter (diameter) is R2, the numerical aperture of the projection optical system PL on the mask M side is NAo, and the numerical aperture of the illumination optical system that illuminates the mask M is NAi, σ = NAi / NAo = R2 / R Defined as 1.

The position of the predetermined surface 6 is located near the front focal position of the zoom lens 10, and the entrance surface of the micro fly's eye lens 11 is located near the rear focal position of the zoom lens 10. . In other words, the zoom lens 10 arranges the predetermined surface 6 and the entrance surface of the micro fly's eye lens 11 substantially in a Fourier transform relationship, and thus the pupil surface of the afocal lens 5 and the entrance surface of the micro fly's eye lens. Are optically substantially conjugated. Therefore, on the entrance surface of the micro fly's eye lens 11, for example, a ring-shaped illumination field centered on the optical axis AX is formed, similarly to the pupil surface of the afocal lens 5. The overall shape of the ring-shaped illumination field varies similarly depending on the focal length of the zoom lens 10. The change in the focal length of the zoom lens 10 is performed by a drive system 23 that operates based on a command from the control system 21.

Each micro lens constituting the micro fly's eye lens 11 has a rectangular cross section similar to the shape of the illumination field to be formed on the mask M (and, consequently, the shape of the exposure area to be formed on the wafer W). Have. The light beam incident on the micro fly's eye lens 11 is two-dimensionally divided by a number of micro lenses, and the illuminated field formed by the light beam incident on the microphone's fly eye lens 11 is provided on the rear focal plane (and thus the illumination pupil). Thus, a secondary light source having substantially the same light intensity distribution as that of the above, that is, a secondary light source composed of a substantially annular light source having an annular shape centered on the optical axis AX is formed.

[0029] Light from an annular secondary light source formed on the rear focal plane of the micro fly's eye lens 11 The bundle is restricted through an aperture stop having a ring-shaped light transmitting portion as required, and after being subjected to the condensing action of the core optical system 12, a mask blind 13 as an illumination field stop is superimposed. Light up. The light beam passing through the rectangular opening (light transmitting portion) of the mask blind 13 illuminates the mask M in a superimposed manner after being subjected to the light condensing action of the imaging optical system 14. The light flux transmitted through the pattern of the mask M forms an image of the mask pattern on the wafer W via the projection optical system PL. On the entrance pupil plane of the projection optical system PL, there is provided a variable aperture stop for defining the numerical aperture of the projection optical system PL, and the operation of the variable aperture stop is performed based on a command from the control system 21. This is performed by the driving system 24.

[0030] In this manner, by performing batch exposure or scan exposure while driving and controlling the wafer W two-dimensionally in a plane (XY plane) orthogonal to the optical axis AX of the projection optical system PL, each exposure area of the wafer W The pattern of the mask M is sequentially exposed. In the batch exposure, the mask pattern is collectively exposed to each exposure region of the wafer according to a so-called step-and-repeat method. In this case, the shape of the illumination area on the mask M is a rectangular shape close to a square, and the cross-sectional shape of each lens element of the micro fly's eye lens 11 is also a rectangular shape close to a square. On the other hand, in the scan exposure, according to a so-called step 'and' scan method, a mask pattern is scanned and exposed on each exposure region of the wafer while the mask and the wafer are relatively moved with respect to the projection optical system. In this case, the shape of the illumination area on the mask M is a rectangular shape with a ratio of the short side to the long side of, for example, 1: 3, and the cross-sectional shape of each lens element of the fly-eye lens 11 has the same shape. It has a similar rectangular shape.

FIG. 2 is a view schematically showing a configuration of a conical axicon system arranged in an optical path between a front lens group and a rear lens group of an afocal lens in the first embodiment. The conical axicon system 7 includes, in order from the light source side, a first prism member 7a having a flat surface facing the light source side and a concave conical refraction surface facing the mask side, and a convex cone having a flat surface facing the mask side and facing the light source side. And a second prism member 7b having a convex refracting surface.

[0032] The concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are formed complementarily so as to be able to abut each other. Further, at least one of the first prism member 7a and the second prism member 7b is moved along the optical axis AX. The distance between the concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b is variably configured. The change in the interval of the conical axicon system 7 is performed by a drive system 25 that operates based on a command from the control system 21.

Here, when the concave conical refraction surface of the first prism member 7a and the convex conical refraction surface of the second prism member 7b are in contact with each other, the conical axicon system 7 functions as a parallel plane plate. However, there is no effect on the formed annular secondary light source. When the concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are separated from each other, the conical axicon system 7 functions as a so-called beam expander. Therefore, the angle of the light beam incident on the predetermined surface 6 changes with the change of the interval of the conical axicon system 7.

FIG. 3 is a diagram illustrating the operation of the conical axicon system on the secondary light source formed in the annular illumination of the first embodiment. In the annular illumination of the first embodiment, the smallest distance formed when the interval between the conical axicon systems 7 is zero and the focal length of the zoom lens 10 is set to a minimum value (hereinafter, referred to as a “standard state”). The annular secondary light source 30a expands the interval of the conical axicon system 7 from zero to a predetermined value, thereby reducing the width (1/2 of the difference between the outer diameter and the inner diameter: indicated by an arrow in the figure). The outer light source and inner diameter of the secondary light source 30b are enlarged without changing. In other words, by the action of the conical axicon system 7, both the annular ratio (inner diameter / outer diameter) and the size (outer diameter) change without changing the width of the annular secondary light source.

FIG. 4 is a view for explaining the action of the zoom lens on the secondary light source formed in the annular illumination of the first embodiment. In the annular illumination of the first embodiment, the annular secondary light source 30a formed in the standard state has a similar overall shape by expanding the focal length of the zoom lens 10 from a minimum value to a predetermined value. It changes to the secondary light source 30c in the form of an annular zone that has been enlarged in an enlarged manner. In other words, by the action of the zoom lens 10, both the width and the size (outer diameter) of the ring-shaped secondary light source change without changing the ring ratio.

FIG. 5 schematically shows the configuration of a first cylindrical lens pair and a second cylindrical lens pair arranged in the optical path between the front lens group and the rear lens group of the afocal lens in the first embodiment. FIG. In Fig. 5, in order from the light source side, The lens pair 8 and the second cylindrical lens pair 9 are arranged. The first pair of cylindrical lenses 8 has, for example, a first cylindrical negative lens 8a having a negative refractive power in the YZ plane and having no refractive power in the XY plane and a positive refractive power in the YZ plane in the order from the light source side. And a non-refractive first cylindrical positive lens 8b in the XY plane.

On the other hand, the second cylindrical lens pair 9 includes, in order from the light source side, for example, a second cylindrical negative lens 9a having a negative refractive power in the XY plane and a non-refractive power in the YZ plane, and the XY plane. And a second cylindrical positive lens 9b having a positive refractive power inside and having no refractive power in the YZ plane. The first cylindrical negative lens 8a and the first cylindrical positive lens 8b are configured to rotate integrally about an optical axis AX by a drive system 26 that operates based on a command from a control system 21. I have. Similarly, the second cylindrical negative lens 9a and the second cylindrical positive lens 9b are configured to rotate integrally about an optical axis AX by a drive system 27 that operates based on a command from a control system 21. ing.

Thus, in the state shown in FIG. 5, the first pair of cylindrical lenses 8 functions as a beam expander having power in the Z direction, and the second pair of cylindrical lenses 9 functions as a beam expander having power in the X direction. In the first embodiment, the power of the first pair of cylindrical lenses 8 and the power of the second pair of cylindrical lenses 9 are set to be equal to each other.

FIG. 6 to FIG. 8 are diagrams for explaining the operation of the first cylindrical lens pair and the second cylindrical lens pair on the secondary light source formed in the annular illumination of the first embodiment. In FIG. 6, the power direction of the first cylindrical lens pair 8 forms an angle of +45 degrees around the optical axis AX with respect to the Z axis, and the power direction of the second cylindrical lens pair 9 changes the optical axis AX with respect to the Z axis. It is set to make an angle of about 45 degrees around it.

Accordingly, the power direction of the first pair of cylindrical lenses 8 and the power direction of the second pair of cylindrical lenses 9 are orthogonal to each other, and in the combined system of the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9, Z The power in the direction and the power in the X direction are the same. As a result, in the perfect circle state shown in Fig. 6, the light beam that passes through the combined system of the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 undergoes an expanding operation with the same power in the Z and X directions. Thus, a secondary light source having a perfect circular ring shape is formed on the illumination pupil. On the other hand, in FIG. 7, the power direction of the first pair of cylindrical lenses 8 makes an angle of, for example, +80 degrees around the optical axis AX with respect to the Z axis, and the power direction of the second pair of cylindrical lenses 9 It is set to form an angle of, for example, 180 degrees around the optical axis AX with respect to the axis. Therefore, in the combined system of the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9, the power in the X direction is larger than the power in the Z direction. As a result, in the horizontal elliptical state shown in FIG. 7, the light beam passing through the combined system of the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 expands with a larger power in the X direction than in the Z direction. In the illumination pupil, a secondary light source elongated in the X direction is formed.

On the other hand, in FIG. 8, the power direction of the first pair of cylindrical lenses 8 forms an angle of, for example, +10 degrees around the optical axis AX with respect to the Z axis, and the power direction of the second pair of cylindrical lenses 9 is The angle is set to, for example, −10 degrees around the optical axis AX. Therefore, the power in the Z direction is larger than the power in the following direction. As a result, in the state of the vertical ellipse shown in FIG. 8, the light flux passing through the combined system of the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 has a larger power in the Z direction than in the X direction. As a result, the illumination pupil is formed with a vertically elongated annular light source elongated in the Z direction.

Further, by setting the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 to an arbitrary state between the perfect circle state shown in FIG. 6 and the horizontal ellipse state shown in FIG. According to the ratio, a horizontally elongated annular light source can be formed. Further, by setting the first cylindrical lens pair 8 and the second cylindrical lens pair 9 to an arbitrary state between the perfect circle state shown in FIG. 6 and the vertical ellipse state shown in FIG. 8, various aspect ratios can be obtained. A vertically long annular light source can be formed.

Next, a description will be given of a circular illumination obtained by setting a diffractive optical element 4b for circular illumination in the illumination optical path instead of the diffractive optical element 4a for annular illumination. When a parallel luminous flux having a rectangular cross section is incident, the diffractive optical element 4b for circular illumination generates, for example, a circular light intensity distribution centered on the optical axis AX in the far field (Fraunhofer diffraction region). Has the function of forming. Therefore, the diffractive optical element 4b The transmitted light flux forms a circular light intensity distribution on the pupil plane of the afocal lens 5, and then exits from the afocal lens 5 as a substantially parallel light flux.

The light beam passing through the afocal lens 5 passes through the zoom lens 10 onto the entrance surface of the micro fly's eye lens 11, similarly to the pupil plane of the afocal lens 5, and has a circle centered on the optical axis AX. An illumination field of a shape is formed. As a result, a circular secondary light source centered on the optical axis AX is also formed on the rear focal plane of the micro fly's eye lens 11. In circular illumination, the concave conical bending surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are in contact with each other so that the conical axicon system 7 functions as a parallel plane plate. Maintained in

When the combined system of the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 is set in a perfect circular state shown in FIG. 6, a perfect circular secondary light source is formed on the illumination pupil. Further, when the combined system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9 is set to the horizontal elliptical state shown in FIG. 7, a horizontally long circular secondary light source is formed on the illumination pupil. Further, when the vertical elliptically set state is set, a vertically long circular secondary light source is formed on the illumination pupil.

Further, by setting the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 to an arbitrary state between the perfect circle state shown in FIG. 6 and the horizontal ellipse state shown in FIG. It is possible to form a horizontally long circular secondary light source according to the ratio. Further, by setting the first cylindrical lens pair 8 and the second cylindrical lens pair 9 to an arbitrary state between the perfect circle state shown in FIG. 6 and the vertical ellipse state shown in FIG. 8, various aspect ratios can be obtained. A vertically long circular secondary light source can be formed.

[0048] As described above, in the first embodiment, the first cylindrical lens pair 8 and the second cylindrical force pair lens 9 are optical element groups (lens groups) having different powers in two orthogonal directions. Both optical element groups are configured to be rotatable about the optical axis AX. Thus, the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 are arranged at or near a position substantially in Fourier transform relation with the illumination pupil, and change the power ratio in two orthogonal directions. An optical element group having a function to change the aspect ratio of the light intensity distribution formed on the illumination pupil. ing.

[0049] As a result, for example, the secondary light source is formed in a desired annular shape or circular shape, for example, because the annular light source or the circular secondary light source is formed slightly vertically or horizontally long. In the case where a line width difference of a pattern occurs in two orthogonal directions due to resist characteristics, etc., the action of the aspect ratio changing means including the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 is used. Accordingly, the aspect ratio of the secondary light source can be adjusted as needed, and the occurrence of a line width difference can be substantially suppressed. When the pattern to be transferred has directionality, the aspect ratio of the secondary light source is adjusted as needed by the action of the aspect ratio changing means (8, 9) to proactively control the annular or circular secondary light source. By setting the length to be long or wide, the occurrence of a line width difference can be substantially suppressed.

As described above, in the illumination optical device (114) of the first embodiment, a simple aspect ratio changing means including the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 allows the illumination optical device (114) to operate simply. Based on the configuration, the aspect ratio of the secondary light source formed on the illumination pupil can be adjusted at any time. Therefore, in the exposure apparatus of the first embodiment, the line width difference of the pattern in the two orthogonal directions is determined by using an illumination optical apparatus capable of adjusting the aspect ratio of the secondary light source formed on the illumination pupil at any time. High-precision exposure that does not substantially occur can be performed.

In the above-described first embodiment, the first cylindrical lens pair 8 and the second cylindrical lens pair 9 constitute an aspect ratio changing unit. However, the present invention is not limited to this. Generally, a first optical element group including a pair of optical elements having rotationally asymmetric power and a second optical element group including a pair of optical elements having rotationally asymmetric power. Thus, the aspect ratio changing means can also be constituted. In this case, at least one of the first optical element group and the second optical element group needs to be configured to be rotatable about the optical axis, and both of them are rotatable about the optical axis. It is preferable that it is comprised.

In the first embodiment described above, the aspect ratio changing means (8, 9) is arranged on the pupil of the afocal lens 5 or in the vicinity thereof. However, in general, such as in the vicinity of the entrance surface of the micro fly's eye lens 11, such as in the vicinity of the entrance plane of the micro fly's eye lens 11, a vertical or horizontal position at or near a position substantially in a Fourier transform relationship with the illumination pupil. It is better to arrange ratio changing means (8, 9). Further, in the above-described first embodiment, the conical axicon system 7 as the changing means is arranged on the light source side of the aspect ratio changing means (8, 9). If the conical axicon system 7 is arranged on the irradiated surface side of (), the diameter of the aspect ratio changing means (8, 9) can be reduced.

The aspect ratio changing means (first cylindrical lens pair 8 and second cylindrical lens pair 9) of the illumination optical device (114) of the first embodiment is, for example, an illumination optical device (114) or When the projection optical system PL has an aberration, the secondary light source is not only corrected to have a slightly vertically or horizontally elongated shape (asymmetric shape). For example, the illumination optical device (1) 14) and the characteristics of the transmittance distribution of the projection optical system PL, the in-plane luminance distribution of the secondary light source is asymmetric (for example, the luminance distribution shape differs in two orthogonal directions in the secondary light source plane, (Typically a saddle-shaped luminance distribution shape), the secondary light source shape is slightly vertically or horizontally elongated so as to be equivalent to the in-plane luminance distribution of the rotationally symmetric secondary light source. You may do so.

Further, a pupil aberration of the projection optical system PL causes a vertical / horizontal difference of the image-side numerical aperture of the projection optical system PL, and a vertical / horizontal difference (V / H difference) of a line width in a mask pattern transfer result. When the aspect ratio occurs, the aspect ratio changing means (the first cylindrical lens pair 8 and the second cylindrical lens pair 9) is appropriately controlled to optimize the shape of the secondary light source, and as a result, to eliminate the difference in the line width aspect ratio. You can also. Alternatively, when non-uniformity of the aspect ratio of the image-side numerical aperture of the projection optical system PL occurs in the image plane, the aspect ratio changing means (first cylindrical lens pair 8 and second cylindrical lens pair 9) is appropriately controlled (distributed). Adjustment) to optimize the shape of the secondary light source, and consequently reduce the in-plane non-uniformity of the line width difference.

Further, for example, due to the aberration and the transmittance distribution characteristics of the illumination optical device (114) and the projection optical system PL, the in-plane luminance distribution of the secondary light source becomes asymmetric, and When the in-plane luminance distribution of the secondary light source becomes non-uniform at a plurality of positions in the area, the in-plane luminance distribution of the secondary light source at a plurality of positions on the irradiated surface is symmetric and uniform ( The distribution may be adjusted so that it is symmetric and uniform.

For the measurement of the shape of the secondary light source and the measurement of the in-plane luminance distribution of the secondary light source, for example, an illumination system luminance distribution measuring device disclosed in JP-A-2000-19012 is used. Just do it. Here, the measurement of the shape of the secondary light source and the measurement of the secondary light source for each illumination condition (the shape of the secondary light source (circular, annular, multipole), σ value, degree of polarization, etc.) The in-plane brightness distribution of the light source should be measured in advance, and the amount of correction by the aspect ratio changing means (first cylindrical lens pair 8 and second cylindrical lens pair 9) should be determined for each lighting condition. Is preferred. When the illumination conditions of the illumination optical device (114) are changed based on the obtained correction amount, the aspect ratio changing means (first cylindrical lens pair 8 and second cylindrical lens pair 9) is controlled. Then, the shape of the secondary light source can be individually optimized for each lighting condition.

In the first embodiment described above, when a vertical / horizontal difference (VZH difference) of the line width occurs in the transfer result of the mask pattern, the vertical / horizontal ratio changing means (first cylindrical lens pair 8 and second cylindrical lens) is used. By appropriately controlling the pair 9), the shape of the secondary light source can be optimized, and as a result, the vertical and horizontal differences in line width can be eliminated. This is because the asymmetry of the secondary light source is corrected when there is asymmetry in the shape of the secondary light source or the in-plane brightness distribution of the secondary light source. The line width and height difference caused by process conditions such as film thickness distribution and in-plane non-uniformity of exposure dose) are both corrected by actively deforming the shape of the secondary light source. Including. In this case, the correction includes taking into consideration the in-image non-uniformity of the line width difference.

The above-described adjustment of the shape of the secondary light source is typically performed when the illumination optical device (114) is manufactured, and thus when the projection exposure apparatus is manufactured. However, when the user of the projection exposure apparatus sets conditions for projecting and exposing the mask pattern onto the wafer using the projection exposure apparatus, the shape of the secondary light source is adjusted in order to optimize the conditions. You can do it. Also, when the shape of the secondary light source or the state of the in-plane luminance distribution of the secondary light source changes due to the temporal change of the illumination optical device (114), and thus the projection exposure apparatus, the shape of the secondary light source may be changed. May be adjusted. In order to improve the performance of the illumination optical device (114) and, consequently, the performance of the projection exposure apparatus, readjustment and replacement of the illumination optical device (114) and, eventually, some parts of the projection exposure apparatus are performed. At that time, the shape of the secondary light source may be readjusted. Also, when setting new illumination conditions in the illumination optical device (1-114), adjust the shape of the secondary light source to optimize the shape of the secondary light source for the new illumination condition. It may be.

FIG. 9 is a diagram schematically showing a configuration of an exposure apparatus working according to the second embodiment of the present invention. FIG. 10 is a diagram schematically illustrating a configuration of an aspect ratio changing unit according to the second embodiment. The second embodiment has a configuration similar to that of the first embodiment. However, in the first embodiment, the aspect ratio changing means including the first pair of cylindrical lenses 8 and the second pair of cylindrical lenses 9 is arranged in the optical path of the afocal lens 5, whereas the second embodiment is different from the first embodiment. The difference is that the aspect ratio changing means (15a, 15b) composed of a pair of Fresnel lenses is arranged in the optical path between the folding mirror 3 and the diffractive optical element (4a, 4b). Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.

Referring to FIGS. 9 and 10, in the second embodiment, the bending mirror 3 and the diffractive optical element

In the optical path between (4a, 4b), a pair of Fresnel lenses 15a and 15b is provided, and an aspect ratio changing means 15 is disposed. The Fresnel lenses 15a and 15b are optical elements each having a refraction function only in one direction. The Fresnel lenses 15a and 15b are configured to rotate around the optical axis AX by a drive system 28 that operates based on a command from the control system 21.

FIG. 11 is a diagram illustrating the operation of a pair of Fresnel lenses on a secondary light source formed in the annular illumination of the second embodiment. In FIG. 11A, the refraction direction of the first Fresnel lens 15a and the refraction direction of the second Fresnel lens 15b are set so as to coincide with the Z-axis direction. Therefore, in the vertical ellipse state shown in FIG. 11 (a), the luminous flux passing through the aspect ratio changing means 15 including the pair of Fresnel lenses 15a and 15b is not diverged in the X-axis direction, but is not affected in the Z-axis direction. As a result of the diverging effect, a secondary light source in the shape of a vertically elongated annular zone elongated in the Z direction is formed on the illumination pupil.

On the other hand, in FIG. 11B, the refraction direction of the first Fresnel lens 15a and the refraction direction of the second Fresnel lens 15b are set so as to coincide with the X-axis direction. Therefore, in the vertical ellipse state shown in FIG. 11A, the light beam passing through the aspect ratio changing means 15 including the pair of Fresnel lenses 15a and 15b is not affected by the divergence in the Z-axis direction, but the X-axis. In the illumination pupil, a secondary light source elongated in the X direction is formed. Although not shown, the refraction direction of the first Fresnel lens 15a is set to match the X-axis direction (or Z-axis direction), and the refraction direction of the second Fresnel lens 15b is set in the Z-axis direction ( Or, it can be set to match. In this perfect circle state, the light flux passing through the aspect ratio changing means 15 composed of the pair of Fresnel lenses 15a and 15b is similarly divergent in the Z-axis direction and the X-axis direction, and the illumination pupil is A secondary light source in the shape of a perfect circular ring is formed.

Similarly, in the circular illumination, when the aspect ratio changing means 15 is set to a perfect circle state, a perfect circular secondary light source is formed on the illumination pupil, and the aspect ratio changing means 15 is changed to the state shown in FIG. When the vertical elliptically shown state is set, a vertically elongated circular secondary light source is formed in the illumination pupil, and when the aspect ratio changing means 15 is set to the horizontal elliptical state shown in FIG. A shaped secondary light source is formed. In addition, any state between the perfect circle state and the vertical ellipse state shown in Fig. 11 (a) or any state between the perfect circle state and the horizontal ellipse state shown in Fig. 11 (b) must be set. Accordingly, it is possible to form a secondary light source having a ring-shaped or circular shape having various aspect ratios.

[0066] As described above, in the second embodiment, the first Fresnel lens 15a and the second Fresnel lens 15b are optical elements having different degrees of divergence in two directions orthogonal to each other. Each is configured to be rotatable about the optical axis AX. Thus, the first Fresnel lens 15a and the second Fresnel lens 15b independently change the degree of divergence of the light beam incident on the diffractive optical element (4a, 4b) as a light beam conversion element in two orthogonal directions. This constitutes an aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil.

As a result, in the second embodiment, as in the first embodiment, for example, an annular or circular secondary light source is formed slightly vertically or horizontally, or the secondary light source is formed. If the line width of the pattern is generated in two orthogonal directions due to resist characteristics and the like even if the pattern is formed in a desired annular or circular shape, the first Fresnel lens 15a and the second Fresnel lens The aspect ratio of the secondary light source can be adjusted as needed by the operation of the aspect ratio changing means 15 comprising 15b, so that the occurrence of a line width difference can be substantially suppressed. If the pattern to be transferred has directionality, the aspect ratio changing means 15 acts to change the aspect ratio of the secondary light source. By adjusting the ratio at any time and positively setting the annular or circular secondary light source to be vertically long or horizontally long, it is possible to substantially suppress the occurrence of a line width difference.

In the second embodiment, the first and second Fresnel lenses 15a and 15b constitute an aspect ratio changing unit. However, the present invention is not limited to this. Generally, a first optical element having different degrees of divergence in two orthogonal directions and a second optical element having different degrees of divergence in two orthogonal directions. Thereby, the aspect ratio changing means can be constituted. In this case, it is necessary that at least one of the first optical element and the second optical element is configured to be rotatable about an axis parallel to the traveling direction of the light beam, and both of them are centered on the optical axis. It is preferable to be configured to be rotatable. Specifically, the aspect ratio changing means is constituted by a pair of diffractive optical elements having a diverging function only in one direction, and the aspect ratio changing means is constituted by a pair of microlens arrays having a refraction function in only one direction. You can also.

FIG. 12 is a view schematically showing a configuration of an exposure apparatus according to the third embodiment of the present invention. FIG. 13 is a diagram schematically showing an internal configuration of an aspect ratio changing unit according to the third embodiment. The third embodiment has a configuration similar to that of the second embodiment. However, in the second embodiment, the aspect ratio changing means is constituted by a pair of Fresnel lenses 15a and 15b, whereas in the third embodiment, the aspect ratio changing means is constituted by one cylindrical zoom lens. The points are different. Hereinafter, the third embodiment will be described focusing on the differences from the second embodiment.

In the third embodiment, as shown in FIG. 12, in the optical path between the bending mirror 3 and the diffractive optical element (4a, 4b), the aspect ratio changing means including one cylindrical zoom lens 16 is arranged. Have been. In the state shown in FIG. 13, the cylindrical zoom lens 16 has a cylindrical negative lens 16a having a negative refractive power in the XY plane and no refractive power in the YZ plane, and a positive refractive power in the XY plane and It is composed of a cylindrical positive lens 16b having no refractive power in a plane.

[0071] The cylindrical zoom lens 16 is configured such that the distance between the cylindrical negative lens 16a and the cylindrical positive lens 16b along the direction of the optical axis AX can be changed. The cylindrical zoom lens 16 includes a cylindrical negative lens 16a and a cylindrical positive lens 1a. 6b are integrally rotatable about the optical axis AX. The change in the distance between the cylindrical negative lens 16a and the cylindrical positive lens 16b and the integral rotation of the cylindrical negative lens 16a and the cylindrical positive lens 16b around the optical axis AX are performed based on a command from the control system 21. This is performed by the operating drive system 29.

FIG. 14 is a diagram illustrating the operation of the cylindrical zoom lens on the secondary light source formed in the third embodiment. FIGS. 14 (a) and (b) show the optical path in the XY plane of the cylindrical zoom lens 16 in the rotational position shown in FIG. 13, and FIGS. 14 (c) and (d) show the optical path shown in FIG. 4 shows an optical path in the YZ plane of the cylindrical zoom lens 16 in a position state. As shown in Fig. 14 (a), in the perfect circle state (ie, the initial state without elliptical illumination), the image point la (virtual image) of the cylindrical negative lens 16a coincides with the front focal point fb of the cylindrical positive lens 16b. Let me. In this case, only the diameter of the parallel light beam incident on the cylindrical zoom lens 16 is changed (enlarged) in the XY plane, and the parallel light beam is incident on the diffractive optical element (4a, 4b) as it is.

[0073] Then, when only the cylindrical negative lens 16a is moved to the light source side along the optical axis direction from the perfect circular state shown in Fig. 14 (a) to increase the interval, as shown in Fig. 14 (b), Since the image point la by the cylindrical negative lens 16a is separated from the front focal point fb of the positive lens 16b toward the light source, the light beam incident on the diffractive optical element (4a, 4b) is converted into a convergent light beam in the XY plane. As shown in FIGS. 14 (c) and (d), even in a perfectly circular state corresponding to FIG. 14 (a) in the YZ plane orthogonal to the XY plane, FIG. ), The parallel light beam incident on the cylindrical zoom lens 16 is incident on the diffractive optical elements (4a, 4b) as a parallel light beam.

FIG. 15 is a diagram showing a ring-shaped light intensity distribution obtained from the illumination pupil when the cylindrical zoom lens is in the perfect circle state and the elliptical state. In FIG. 15, (a) shows the shape of the secondary light source formed on the illumination pupil in the perfect circular state (initial state) of the cylindrical zoom lens 16 shown in FIGS. 14 (a) and (c) (for annular illumination). (B) is a diagram showing the light intensity distribution (vertical axis is light intensity I) of the secondary light source having a perfect circular ring shape in (a) along the X direction. (C) is a diagram showing the light intensity distribution (the vertical axis is light intensity I) of the secondary light source in the shape of a perfect circular ring in (a) along the Ζ direction. (D) shows the shape of the secondary light source formed on the illumination pupil in the elliptical state of the cylindrical zoom lens 16 shown in FIGS. 14 (b) and (d) (diffractive optical element for annular illumination). 4e), and (e) is a diagram showing the light intensity distribution (the vertical axis is light intensity I) of the secondary light source having an elliptical annular shape in (d) along the X direction, and (f) is a diagram showing (f). () Is a diagram showing the light intensity distribution along the Z direction (light intensity I) of the secondary light source in the shape of an elliptical ring in (d). As shown in Fig. 15 (e), the light intensity distribution along the X direction of the secondary light source in the shape of an elliptical orbicular zone obtained in the elliptical state is applied to the illumination pupil only by the action of the diffractive optical element 4a for orbicular illumination. The light intensity distribution formed is a convolution of the light intensity distribution formed on the illumination pupil by the action of the cylindrical zoom lens 16 alone. Become.

In FIG. 15 (d), a hatched area (shaded area) in the figure is an area Im where the light intensity is maximum, and a light intensity gradient area Is where the light intensity gradually decreases is located around the area Im. are doing. Fig. 15 (d) The elliptical ring-shaped light region shown by the solid line is a force that spreads in the X direction more than the perfect circular ring-shaped light region shown in Fig. 15 (a). See Figs. 15 (e) and (f). When considered in terms of moment, the diameter of the annular zone is smaller in the X direction than in the Z direction.

As described above, in the third embodiment, the cylindrical negative lens 16a and the cylindrical positive lens 16b are set in the interval state shown in FIGS. 14A and 14B without depending on the rotational position of the cylindrical zoom lens 16. When set, a secondary light source having a perfect circular ring shape or perfect circular shape is formed on the illumination pupil. In addition, the cylindrical lens zoom lens 16 is set to the first rotational position shown in FIG. 13, and the cylindrical negative lens 16a and the cylindrical positive lens 16b are set to the intervals shown in FIGS. 14 (b) and (d). Then, a secondary light source having an elliptical annular shape or an elliptical shape extending in the X direction is formed on the illumination pupil.

Further, the cylindrical zoom lens 16 is set to a second rotation position in which the cylindrical zoom lens 16 is rotated 90 degrees around the optical axis AX from the rotation position shown in FIG. 13, and the cylindrical negative lens 16a and the cylindrical positive lens 16b are illustrated. 14 When the intervals shown in (b) and (d) are set, a secondary light source having an elliptical annular shape or an elliptical shape extending in the Z direction is formed on the illumination pupil. Furthermore, by setting an arbitrary state between the perfect circular state and the elliptical state in the first rotational position state and an arbitrary state between the perfect circular state and the elliptical state in the second rotational position state, A ring-shaped or circular secondary light source with various aspect ratios can be formed.

As described above, in the third embodiment, the cylindrical lens zoom lens 16 that is rotatable about the optical axis AX includes the folding mirror 3 and the diffractive optical elements (4a, 4b) serving as light flux converting elements. The light intensity distribution formed on the illumination pupil by being placed in the optical path between the light sources (and thus between the light source 1 and the diffractive optical element (4a, 4b)) and changing the power independently in two orthogonal directions And an aspect ratio changing means for changing the aspect ratio.

As a result, in the third embodiment, as in the second embodiment, for example, an annular or circular secondary light source is formed slightly vertically or horizontally, or the secondary light source is formed. Even if the pattern is formed in the desired annular or circular shape, if there is a line width difference of the pattern in two orthogonal directions due to resist characteristics, etc., a cylindrical rotatable about the optical axis AX The aspect ratio of the secondary light source can be adjusted as needed by the operation of the aspect ratio changing means including the zoom lens 16 to substantially suppress the occurrence of a line width difference. If the pattern to be transferred has directivity, the aspect ratio of the secondary light source is adjusted as needed by the operation of the aspect ratio changing means 16 to positively orient the annular or circular secondary light source. By setting it to be horizontally long, the occurrence of a line width difference can be substantially suppressed.

In the third embodiment described above, the aspect ratio changing means is constituted by one cylindrical zoom lens 16 rotatable around the optical axis AX. However, the present invention is not limited to this. For example, as shown in FIG. 16, a first cylindrical zoom lens having a function of changing power in one of two orthogonal directions, A modification in which the aspect ratio changing means is constituted by the second cylindrical zoom lens having the function of changing the power in the other direction of the two directions is also possible.

Referring to the modification of FIG. 16, the aspect ratio changing means includes, in order from the light source side, a first cylindrical zoom lens 17 having a function of changing the power in the Z direction, and a function of changing the power in the X direction. And a second cylindrical zoom lens 18 having The first cylindrical zoom lens 17 has a negative refractive power in the YZ plane and has no refractive power in the XY plane, and has a positive refractive power in the YZ plane and has no refractive power in the XY plane. It is composed of a power cylindrical positive lens 17b.

Further, the second cylindrical zoom lens 18 has a negative refractive power in the XY plane and has It comprises a cylindrical negative lens 18a having no refractive power in a plane and a cylindrical positive lens 18b having a positive refractive power in the XY plane and having no refractive power in the plane. The first cylindrical zoom lens 17 is configured so that the distance between the cylindrical negative lens 17a and the cylindrical positive lens 17b along the direction of the optical axis AX can be changed.

Similarly, the second cylindrical zoom lens 18 is configured such that the distance between the cylindrical negative lens 18a and the cylindrical positive lens 18b along the direction of the optical axis AX can be changed. In the modified example of FIG. 16, by changing the interval between the first cylindrical zoom lens 17 and the interval between the second cylindrical zoom lenses 18 as appropriate, various aspect ratios are obtained based on the same principle as in the third embodiment. A secondary light source having a ring shape or a circular shape can be formed.

[0085] In the second embodiment and the third embodiment, the same control as the aspect ratio changing means of the first embodiment may be performed.

[0086] In the exposure apparatus of the above-described embodiment, the reticle (mask) is illuminated by the illumination device (illumination step), and the transfer pattern formed on the mask is exposed on the photosensitive substrate using the projection optical system. By performing the (exposure step), a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. FIG. 17 is a flowchart of an example of a method for obtaining a semiconductor device as a microdevice by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the present embodiment. It will be described with reference to FIG.

First, in step 301 of FIG. 17, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the one lot wafer. Then, in step 303, using the exposure apparatus of this embodiment, the pattern image on the mask is sequentially exposed and transferred to each shot area on the one lot of wafers via the projection optical system. Thereafter, in step 304, the photoresist on the one lot wafer is developed, and in step 305, the pattern on the mask is etched on the one lot wafer using the resist pattern as a mask. Is formed in each shot area on each wafer.

After that, a circuit pattern of a further upper layer is formed, etc. Are manufactured. According to the above-described semiconductor device manufacturing method, a semiconductor device having an extremely fine circuit pattern can be obtained with good throughput. In step 301-step 305, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and the force of performing each of the steps of exposure, development, and etching is performed on the wafer prior to these steps. After the silicon oxide film is formed on the silicon oxide film, it is needless to say that a resist may be applied on the silicon oxide film, and the respective steps such as exposure, development, and etching may be performed.

In the exposure apparatus of the present embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). . Hereinafter, an example of the method at this time will be described with reference to the flowchart in FIG. In FIG. 18, in a pattern forming step 401, a so-called optical lithography step of transferring and exposing a mask pattern onto a photosensitive substrate (a glass substrate coated with a resist) using the exposure apparatus of the present embodiment is executed. . By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes various steps such as a developing step, an etching step, and a resist stripping step, so that a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step 402.

Next, in the color filter forming step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or R, G, A color filter is formed by arranging a plurality of sets of filters of three stripes B in the horizontal scanning line direction. Then, after the color filter forming step 402, a cell assembling step 403 is performed. In a cell assembling step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern forming step 401, the color filter obtained in the color filter forming step 402, and the like. In the cell assembling step 403, for example, a liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, and a liquid crystal panel ( Liquid crystal cell).

[0091] Thereafter, in the module assembling step 404, the assembled liquid crystal panel (liquid crystal cell) Attach various components such as an electric circuit and a backlight for performing the display operation of) to complete the liquid crystal display device. According to the above-described method for manufacturing a liquid crystal display device, a liquid crystal display device having an extremely fine circuit pattern can be obtained with high throughput.

[0092] In each of the above-described embodiments, the present invention is described with reference to the annular illumination and the circular illumination as an example. The present invention is not limited to this. The present invention can be applied.

In each of the above-described embodiments, the present invention is applied to an illumination optical device having a specific configuration as shown in FIG. 1. The present invention is not limited to this. The present invention can also be applied to the embodiment shown in FIG. 10 of Japanese Patent Application Publication No. JP-A-2003-0038931 and the corresponding embodiment shown in FIG. 1 of the specification and drawing of International Application No.PCTZJP03Z15447. is there. Here, in the embodiment of FIG. 10 of JP-A-2003-66867 and the corresponding US Patent Application Publication US2003Z0038931, two pairs of cylindrical lenses are connected between the zoom lens 4 and the fly-eye lens 5. Can be arranged in the optical path. In the embodiment of FIG. 1 of the specification and drawings of International Application No. PCT / JP03 / 15447, two pairs of cylindrical lenses are provided in the optical path of the afocal lens 5 and between the zoom lens 7 and the fly-eye lens 5. It can be placed in the optical path.

[0094] Further, in each of the above-described embodiments, the present invention has been described by taking, as an example, an exposure apparatus provided with an illumination optical device. However, the present invention is applied to a general illumination optical device for illuminating an irradiated surface other than a mask. It is clear that the invention can be applied.

Explanation of reference numerals

[0095] 1 light source

4 Diffractive optical element

5 A force lens

7 Conical axicon system

8, 9

10 Zoom lens

11 12 Condenser optics

13 Mask blind

14 Imaging optics

15a, 15b Fresno lens

16, 17, 18 Cylindrical cane zoom lens

M mask

PL projection optical system

W wafer

20 Input means

21 Control system

22-29 drive system

Claims

The scope of the claims

[1] An illumination optical device that illuminates a surface to be irradiated based on a light beam from a light source,

The aspect ratio changing means is an optical element group disposed at or near a position substantially in Fourier transform relationship with the illumination pupil and having a function of changing a power ratio in two orthogonal directions. An illumination optical device, comprising:

[2] The optical element group includes a first optical element group having different powers in two orthogonal directions, and a second optical element group having different powers in two orthogonal directions. 2. The illumination optical device according to claim 1, wherein at least one of the optical element group and the second optical element group is configured to be rotatable around an optical axis.

3. The illumination optical device according to claim 1, wherein both the first optical element group and the second optical element group are configured to be rotatable around the optical axis.

4. The illumination optical device according to claim 1, wherein the optical element group is a lens group.

[5] The apparatus further comprises changing means for continuously changing the size of the light intensity distribution formed on the illumination pupil,

The illumination optical device according to any one of claims 1 to 4, wherein the optical element group is disposed in an optical path closer to the light source than the changing unit.

[6] The changing unit changes a size of an outer shape of a light intensity distribution formed on the illumination pupil, and a second unit changes a ring ratio of a light intensity distribution formed on the illumination pupil. 6. The illumination optical device according to claim 5, comprising: 2 changing means.

[7] First changing means for changing the size of the outer shape of the light intensity distribution formed on the illumination pupil, and second changing means for changing the annular ratio of the light intensity distribution formed on the illumination pupil. Further comprising a changing means having

The illumination optical device according to any one of claims 1 to 4, wherein the optical element group is arranged in an optical path closer to the light source than the changing unit.

[8] An illumination optical device that illuminates a surface to be irradiated based on a light beam from a light source, A light beam conversion element for converting a light beam from the light source into a light beam having a predetermined cross section;

A forming optical system for forming a predetermined light intensity distribution on an illumination pupil that is substantially in a Fourier transform relationship with the irradiation surface based on the light beam from the light beam conversion element; Aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil by independently changing the degree of divergence of the light beam in two orthogonal directions. Lighting optics.

[9] The aspect ratio changing means includes a first optical element having different degrees of divergence in two orthogonal directions, and a second optical element having different degrees of divergence in two orthogonal directions, The illumination optics according to claim 8, wherein at least one of the first optical element and the second optical element is configured to be rotatable around an axis parallel to a traveling direction of the light beam. apparatus.

10. The illumination according to claim 8, wherein both the first optical element and the second optical element are configured to be rotatable around an axis parallel to a traveling direction of the light beam. Optical device.

11. The illumination optical device according to claim 9, wherein the first optical element and the second optical element each include a diffraction optical element having a diverging function only in one direction.

12. The illumination optical device according to claim 9, wherein the first optical element and the second optical element each have a Fresnel lens having a refraction function only in one direction.

[13] The illumination according to claim 9 or 10, wherein the first optical element and the second optical element have a lens having a refraction function only in one direction.

14. The illumination optical device according to claim 8, wherein the forming optical system has an optical integrator.

[15] In an illumination optical device that illuminates a surface to be irradiated based on a light beam from a light source,

A light beam conversion element for converting a light beam from the light source into a light beam having a predetermined cross section When,

A forming optical system for forming a predetermined light intensity distribution on an illumination pupil substantially in Fourier transform relation with the surface to be illuminated based on the light beam from the light beam converting element; the light source and the light beam converting element And an aspect ratio changing means for changing an aspect ratio of a light intensity distribution formed on the illumination pupil by independently changing power in two orthogonal directions. Illumination optics comprising:

16. The illumination optical device according to claim 15, wherein the aspect ratio changing unit includes a cylindrical zoom lens rotatable around an optical axis.

[17] The aspect ratio changing means includes a first cylindrical zoom lens having a function of changing power in one of the two orthogonal directions, and the other of the two orthogonal directions. 16. The illumination optical device according to claim 15, further comprising a second cylindrical zoom lens having a function of changing power.

[18] The illumination optical device according to any one of [15] to [ ₇ ], wherein the forming optical system includes an optical integrator.

[19] In an exposure apparatus for transferring a mask pattern onto a photosensitive substrate,

An illumination optical device according to any one of claims 1 to 18,

An exposure apparatus, comprising: a projection optical system for projecting the mask pattern set on the irradiation surface onto the photosensitive substrate.

[20] In an exposure method for transferring a pattern of a mask onto a photosensitive substrate,

Illuminating the mask set on the illuminated surface using the illumination optical device according to any one of claims 1 to 18,

Projecting and exposing the pattern of the mask onto the photosensitive substrate.