JPWO2004112107A1 - Illumination optical apparatus, exposure apparatus, and exposure method - Google Patents

Abstract

An illumination optical device capable of adjusting the aspect ratio of a secondary light source formed on an illumination pupil as needed based on a simple configuration. An illumination optical device that illuminates the illuminated surface (M) based on the light flux from the light source (1). Aspect ratio changing means (8, 9) is provided for changing the aspect ratio of the light intensity distribution formed on the illumination pupil substantially having a Fourier transform relationship with the surface to be irradiated. The aspect ratio changing means is disposed at or near the position substantially in a Fourier transform relationship with the illumination pupil, and has a function of changing the power ratio in two orthogonal directions (8a, 8b, 9a). 9b).

Description

  The present invention relates to an illumination optical apparatus, an exposure apparatus, and an exposure method, and more particularly to an illumination optical apparatus suitable for an exposure apparatus for manufacturing a microdevice such as a semiconductor element, an imaging element, a liquid crystal display element, and a thin film magnetic head in a lithography process. .

  In a typical exposure apparatus of this type, a light beam emitted from a light source is incident on a micro fly's eye lens (or fly eye lens), and a secondary light source composed of a number of light sources is formed on the rear focal plane. The light beam from the secondary light source is restricted through an aperture stop disposed in the vicinity of the rear focal plane of the micro fly's eye lens as necessary and then enters the condenser lens.

  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) onto the wafer. The pattern formed on the mask is highly integrated, and it is essential to obtain a uniform illuminance distribution on the wafer in order to accurately transfer this fine pattern onto the wafer.

  In recent years, by changing the size of the secondary light source formed on the illumination pupil via the micro fly's eye lens, the illumination coherency σ (σ value = aperture aperture diameter / projection optical system pupil diameter, or Attention has been focused on a technique for changing (σ value = exit-side numerical aperture of illumination optical system / incident-side numerical aperture of projection optical system). Further, attention has been paid to a technique for improving the depth of focus and the resolution of the projection optical system by forming an annular or quadrupolar secondary light source on the illumination pupil via a micro fly-eye lens.

  In the prior art, for example, when performing annular illumination based on an annular secondary light source, the secondary light source is formed in a slightly vertically or horizontally annular shape, thereby reducing the line width of the pattern transferred onto the wafer. A different phenomenon in the vertical direction and the horizontal direction, that is, a difference in the line width of the pattern may occur in two orthogonal directions. Even if the secondary light source is formed in a desired annular shape, a line width difference between the patterns may occur in two orthogonal directions due to resist characteristics and the like. If the pattern to be transferred has directionality, it may be desirable to positively set the annular secondary light source formed on the illumination pupil to be vertically long or horizontally long.

  The present invention has been made in view of the above-described problems, and provides an illumination optical device capable of adjusting the aspect ratio of a secondary light source formed on an illumination pupil as needed based on a simple configuration. Objective. In addition, by using an illumination optical device that can adjust the aspect ratio of the secondary light source formed on the illumination pupil as needed, a high-precision pattern line width difference is not substantially generated in two orthogonal directions. An object of the present invention is to provide an exposure apparatus and an exposure method capable of performing exposure.

In order to solve the above problems, in the first embodiment of the present invention, in the illumination optical device that illuminates the irradiated surface based on the light beam from the light source,
Aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil substantially in a Fourier transform relationship with the illuminated surface,
The aspect ratio changing means includes an optical element group that is disposed at or near a position substantially in a Fourier transform relationship with the illumination pupil and has a function of changing a power ratio in two orthogonal directions. An illumination optical device is provided.

  According to a preferred aspect of the first aspect, 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. 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. Moreover, it is preferable that both the first optical element group and the second optical element group are configured to be rotatable about the optical axis. The optical element group is preferably a lens group.

  In the first embodiment, the first optical element group and the second optical element group preferably each include a pair of optical elements having rotationally asymmetric power, and each include a pair of cylindrical lenses. Is more preferable. The rotationally asymmetric power means a rotationally asymmetric power with respect to the optical axis of the optical element having the rotationally asymmetric power.

  Moreover, in the first embodiment, it is preferable to further include a changing unit that continuously changes the magnitude of the light intensity distribution formed on the illumination pupil. At this time, the optical element group is more than the changing unit. Is preferably disposed in the light path on the light source side. Here, the changing means changes the outer zone ratio of the light intensity distribution formed on the illumination pupil and the first changing means for changing the size of the outer shape of the light intensity distribution formed on the illumination pupil. 2 change means.

In the second embodiment of the present invention, in the illumination optical device that illuminates the irradiated surface based on the light flux from the 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 in an illumination pupil substantially in a Fourier transform relationship with the illuminated surface, based on the light flux from the light flux 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 flux incident on the light flux conversion element in two orthogonal directions. An illumination optical device is provided.

  According to a preferred aspect of the second aspect, 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. And 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. Further, it is preferable that both the first optical element and the second optical element are configured to be rotatable about an axis parallel to the traveling direction of the light beam. The axis parallel to the traveling direction of the light beam is preferably an optical axis.

  According to a preferred aspect of the second embodiment, the first optical element and the second optical element each have a diffractive optical element having a divergence function only in one direction. Alternatively, the first optical element and the second optical element preferably each have a Fresnel lens having a refractive function only in one direction. Alternatively, each of the first optical element and the second optical element preferably has a microlens array having a refractive function only in one direction. The forming optical system preferably has an optical integrator.

In the third aspect of the present invention, in the illumination optical device that illuminates the irradiated surface based on the light flux from the 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 in an illumination pupil substantially in a Fourier transform relationship with the illuminated surface, based on the light flux from the light flux conversion element;
In order to change the aspect ratio of the light intensity distribution formed in the illumination pupil by changing the power independently in two orthogonal directions arranged in the optical path between the light source and the light beam conversion element. The illumination optical device is provided with the aspect ratio changing means.

  According to a preferred aspect of the third aspect, the aspect ratio changing means has a cylindrical zoom lens that is rotatable about the 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 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 forming optical system preferably has an optical integrator.

  According to a fourth aspect of the present invention, in an exposure apparatus that transfers a mask pattern onto a photosensitive substrate, the illumination optical apparatus according to the first to third aspects and the mask pattern set on the irradiated surface are An exposure apparatus is provided that includes a projection optical system that projects onto a photosensitive substrate.

  In 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 illuminate the mask set on the irradiated surface. There is provided an exposure method comprising a step and a step of projecting and exposing a pattern of the mask onto the photosensitive substrate.

  In the illumination optical apparatus according to the typical aspect of the present invention, the two formed on the illumination pupil based on the simple configuration by the action of the aspect ratio changing means including the first cylindrical lens pair and the second cylindrical lens pair. The aspect ratio of the next light source can be adjusted at any time. Therefore, in the exposure apparatus and the exposure method of the present invention, the line width difference between the patterns in the two orthogonal directions is substantially reduced by using the illumination optical apparatus that can adjust the aspect ratio of the secondary light source formed on the illumination pupil as needed. Therefore, it is possible to perform high-precision exposure that does not occur automatically, and as a result, it is possible to manufacture a good microdevice by high-precision exposure.

FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram schematically showing the configuration of a conical axicon system disposed 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 diagram for explaining the action of the conical axicon system on the secondary light source formed in the annular illumination of the first embodiment.
FIG. 4 is a diagram for explaining the action of the zoom lens on the secondary light source formed in the annular illumination of the first embodiment.
FIG. 5 is a diagram schematically showing a configuration of a first cylindrical lens pair and a second cylindrical lens pair arranged in an optical path between a front lens group and a rear lens group of an afocal lens in the first embodiment. It is.
FIG. 6 is a diagram 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 diagram 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. 8 is a diagram illustrating 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 drawing 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 aspect ratio changing means in the second embodiment.
FIG. 11 is a diagram for explaining the action of a pair of Fresnel lenses on a secondary light source formed in annular illumination of the second embodiment.
FIG. 12 is a drawing 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 aspect ratio changing means in the third embodiment.
FIG. 14 is a diagram for explaining the action of a cylindrical zoom lens on a secondary light source formed in the third embodiment.
FIG. 15 is a diagram showing a light intensity distribution obtained by an illumination pupil in a circular state and an elliptical state of a cylindrical zoom lens.
FIG. 16 is a diagram schematically showing an internal configuration of 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.

Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to the first embodiment of the present invention. In FIG. 1, the Z-axis is along the normal direction of the wafer, which is a photosensitive substrate, the Y-axis is parallel to the plane of FIG. 1 in the wafer plane, and the direction is perpendicular to the plane of FIG. X axis is set for each. In FIG. 1, the illumination optical device is set to perform annular illumination.

  The exposure apparatus of FIG. 1 includes, for example, a KrF excimer laser light source that supplies light with a wavelength of 248 nm or an ArF excimer laser light source that supplies light with a wavelength of 193 nm as the light source 1 for supplying exposure light (illumination light). ing. A substantially parallel light beam emitted from the light source 1 along the Z direction has a rectangular cross section extending along the X direction, and is incident on a beam expander 2 including a pair of lenses 2a and 2b. Each lens 2a and 2b has a negative refracting power and a positive refracting power in the plane of FIG. 1 (in the YZ plane), respectively. Accordingly, 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 via a beam expander 2 as a shaping optical system is deflected in the Y direction by a bending mirror 3 and then enters a diffractive optical element (DOE) 4a for annular illumination. In general, 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, an annular light intensity distribution around the optical axis AX in the far field (Fraunhofer diffraction region) when a parallel light beam having a rectangular cross section is incident. .

  The diffractive optical element 4a for annular illumination is configured to be detachable with respect to the illumination optical path, and is configured to be switchable with a diffractive optical element 4b for circular illumination, for example. The configuration and operation of the diffractive optical element 4b for circular illumination will be described later. Here, switching between the diffractive 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 relating to various masks to be sequentially exposed in accordance with a step-and-repeat method or a step-and-scan method is input to the control system 21 via an input means 20 such as a keyboard.

  A light beam that has passed through the diffractive optical element 4 a serving as a light beam conversion element enters an afocal lens (relay optical system) 5. The afocal lens 5 is set so that the front focal position thereof and the position of the diffractive optical element 4a substantially coincide with each other, and the rear focal position thereof substantially coincides with the position of the predetermined surface 6 indicated by a broken line in the drawing. System (non-focal optical system). Therefore, the substantially parallel light beam incident on the diffractive optical element 4 a forms an annular 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 beam.

  In the optical path between the front lens group 5a and the rear lens group 5b of the afocal lens 5, the conical axicon system 7 as the second changing means and the first cylindrical are located in the pupil or in the vicinity thereof in order from the light source side. The lens pair 8 and the second cylindrical lens pair 9 are disposed, and the detailed configuration and operation thereof will be described later. Hereinafter, in order to simplify the description, the basic configuration and operation of the first embodiment will be described ignoring the operations of the conical axicon system 7, the first cylindrical lens pair 8, and the second cylindrical lens pair 9. .

  The light beam that has passed through the afocal lens 5 enters a micro fly's eye lens 11 as an optical integrator through a zoom lens (variable magnification optical system) 10 for varying σ value as first changing means. The σ value is the size of the illumination light beam or light source image formed on the pupil of the projection optical system PL, where R1 is the size (diameter) of the secondary light source formed on the pupil (illumination pupil) of the illumination optical system. When (diameter) is R2, the numerical aperture on the mask M side of the projection optical system PL is NAo, and the numerical aperture of the illumination optical system that illuminates the mask M is NAi, it is defined as σ = NAi / NAo = R2 / R1 Is done.

  The position of the predetermined surface 6 is arranged in the vicinity of the front focal position of the zoom lens 10, and the incident surface of the micro fly's eye lens 11 is arranged in the vicinity of the rear focal position of the zoom lens 10. In other words, the zoom lens 10 arranges the predetermined surface 6 and the incident surface of the micro fly's eye lens 11 substantially in a Fourier transform relationship, and as a result, the pupil surface of the afocal lens 5 and the incident surface of the micro fly's eye lens. Are arranged almost conjugate optically. Accordingly, on the incident surface of the micro fly's eye lens 11, for example, a ring-shaped illumination field with the optical axis AX as the center is formed, like the pupil surface of the afocal lens 5. The overall shape of the annular illumination field changes in a similar manner 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 microlens 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 thus the shape of the exposure region to be formed on the wafer W). A light beam incident on the micro fly's eye lens 11 is two-dimensionally divided by a large number of microlenses, and an illumination field formed by the light beam incident on the micro fly's eye lens 11 on the rear focal plane (and thus the illumination pupil). A secondary light source having the same light intensity distribution, that is, a secondary light source composed of a ring-shaped substantial surface light source centered on the optical axis AX is formed.

  The light flux from the annular secondary light source formed on the rear focal plane of the micro fly's eye lens 11 is restricted through an aperture stop having an annular light transmitting portion as necessary, and the condenser optical system 12 After receiving the condensing action, the mask blind 13 as an illumination field stop is illuminated in a superimposed manner. The light beam that has passed through the rectangular opening (light transmitting portion) of the mask blind 13 receives the light condensing action of the imaging optical system 14 and then illuminates the mask M in a superimposed manner. The light beam that has passed through the pattern of the mask M forms an image of the mask pattern on the wafer W via the projection optical system PL. The entrance pupil plane of the projection optical system PL is provided with a variable aperture stop for defining the numerical aperture of the projection optical system PL. The drive of the variable aperture stop is based on a command from the control system 21. Is done.

  Thus, 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 region of the wafer W is masked. M patterns are 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 scan exposure, the mask pattern is scanned and exposed to each exposure region of the wafer while moving the mask and wafer relative to the projection optical system in accordance with a so-called step-and-scan method. In this case, the shape of the illumination area on the mask M is a rectangular shape having a ratio of short side to long side of, for example, 1: 3, and the cross-sectional shape of each lens element of the micro fly's eye lens 11 is a similar rectangular shape. It becomes a shape.

  FIG. 2 is a diagram schematically showing the configuration of a conical axicon system disposed in the optical path between the front lens group and the rear lens group of the 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 refractive surface facing the mask side, and a convex conical shape facing the plane toward the mask side and the light source side. And a second prism member 7b facing the refractive surface.

  The concave conical refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are complementarily formed so as to be in contact with each other. Further, at least one of the first prism member 7a and the second prism member 7b is configured to be movable along the optical axis AX, and the concave conical refracting surface of the first prism member 7a and the second prism member 7b. The distance from the convex conical refracting surface is variable. A 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, in a state where the concave conical refracting 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, the conical axicon system 7 functions and is formed as a parallel plane plate. There is no effect on the secondary light source in the annular zone. However, 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 incident light beam on the predetermined surface 6 changes with the change in the interval of the conical axicon system 7.

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

  FIG. 4 is a diagram 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 enlarges the focal length of the zoom lens 10 from a minimum value to a predetermined value, so that the overall shape is similar. To a secondary light source 30c having a ring-shaped shape. In other words, due to the action of the zoom lens 10, both the width and size (outer diameter) change without changing the annular ratio of the annular secondary light source.

  FIG. 5 is a diagram schematically illustrating a configuration of a first cylindrical lens pair and a second cylindrical lens pair arranged in an optical path between a front lens group and a rear lens group of an afocal lens in the first embodiment. It is. In FIG. 5, a first cylindrical lens pair 8 and a second cylindrical lens pair 9 are arranged in order from the light source side. The first cylindrical lens pair 8 has, in order from the light source side, 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 also having a positive refractive power in the YZ plane. And a first cylindrical positive lens 8b having no refractive power in the XY plane.

  On the other hand, the second cylindrical lens pair 9 is, 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 having no refractive power in the YZ plane, and also positively refracting in the XY plane. The second cylindrical positive lens 9b has a power and has no refractive power in the YZ plane. The first cylindrical negative lens 8 a and the first cylindrical positive lens 8 b are configured to rotate integrally around the optical axis AX by a drive system 26 that operates based on a command from the control system 21. Similarly, the second cylindrical negative lens 9a and the second cylindrical positive lens 9b are configured to rotate integrally around the optical axis AX by a drive system 27 that operates based on a command from the control system 21. ing.

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

  6-8 is a figure explaining the effect | action of the 1st cylindrical lens pair and the 2nd cylindrical lens pair with respect to the secondary light source formed in the annular illumination of 1st 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 rotates around the optical axis AX with respect to the Z axis. Are set to form an angle of -45 degrees.

  Therefore, the power direction of the first cylindrical lens pair 8 and the power direction of the second cylindrical lens pair 9 are orthogonal to each other, and the power in the Z direction in the synthesis system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9 The power in the X direction is the same. As a result, in the perfect circle state shown in FIG. 6, the light beam passing through the synthesis system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9 is subjected to an expanding action with the same power in the Z direction and the X direction. Thus, a secondary light source in the shape of a perfect ring zone is formed on the illumination pupil.

  On the other hand, in FIG. 7, the power direction of the first cylindrical lens pair 8 forms 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 cylindrical lens pair 9 is relative to the Z axis. For example, an angle of -80 degrees is set around the optical axis AX. Therefore, in the combined system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9, the power in the X direction is larger than the power in the Z direction. As a result, in the horizontal ellipse state shown in FIG. 7, the light beam passing through the combined system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9 has an expanding action with greater power in the X direction than in the Z direction. As a result, a horizontally elongated secondary light source elongated in the X direction is formed on the illumination pupil.

  On the other hand, in FIG. 8, the power direction of the first cylindrical lens pair 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 cylindrical lens pair 9 is light with respect to the Z axis. For example, an angle of −10 degrees is set around the axis AX. Therefore, in the combined system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9, the power in the Z direction is larger than the power in the X direction. As a result, in the vertical ellipse state shown in FIG. 8, the light beam passing through the combined system of the first cylindrical lens pair 8 and the second cylindrical lens pair 9 has an expanding action with greater power in the Z direction than in the X direction. As a result, a vertically elongated annular light source elongated in the Z direction is formed on the illumination pupil.

  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 horizontal ellipse state shown in FIG. 7, various aspect ratios are met. A horizontally elongated secondary 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 are obtained. A vertically long secondary light source having an annular zone can be formed.

  Next, circular illumination obtained by setting the circular illumination diffractive optical element 4b in the illumination optical path instead of the annular illumination diffractive optical element 4a will be described. When a parallel light beam having a rectangular cross section is incident, the diffractive optical element 4b for circular illumination forms, for example, a circular light intensity distribution around the optical axis AX in the far field (Fraunhofer diffraction region). It has the function to do. Therefore, the light beam that has passed through the diffractive optical element 4 b forms a circular light intensity distribution on the pupil plane of the afocal lens 5, and then is emitted from the afocal lens 5 as a substantially parallel light beam.

  The light beam that has passed through the afocal lens 5 passes through the zoom lens 10 on the incident surface of the micro fly's eye lens 11, similarly to the pupil surface of the afocal lens 5, in a circular illumination centered on the optical axis AX. A field 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 refracting surface of the first prism member 7a and the convex conical refracting surface of the second prism member 7b are kept in contact with each other so that the conical axicon system 7 functions as a plane-parallel plate. Is done.

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

  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 horizontal ellipse state shown in FIG. 7, various aspect ratios are met. A horizontally long secondary 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 are obtained. A vertically long circular secondary light source can be formed.

  As described above, in the first embodiment, the first cylindrical lens pair 8 and the second cylindrical lens pair 9 are optical element groups (lens groups) having different powers in two orthogonal directions, respectively. The element group is configured to be rotatable about the optical axis AX. Thus, the first cylindrical lens pair 8 and the second cylindrical lens pair 9 are arranged at or near the position substantially in the Fourier transform relationship with the illumination pupil, and change the power ratio in two orthogonal directions. It is an optical element group having a function, and constitutes aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil.

  As a result, for example, a ring-shaped or circular secondary light source is formed slightly vertically or horizontally, or even if the secondary light source is formed in a desired ring-shaped or circular shape, resist characteristics, etc. If the difference in line width of the pattern occurs in two orthogonal directions, the aspect ratio of the secondary light source is affected by the aspect ratio changing means including the first cylindrical lens pair 8 and the second cylindrical lens pair 9. The ratio can be adjusted at any time to substantially suppress the occurrence of a line width difference. If the pattern to be transferred has directionality, the aspect ratio changing means (8, 9) can be used to adjust the secondary light source aspect ratio as needed to actively use the annular or circular secondary light source. By setting the length to be vertically long or horizontally long, the occurrence of a line width difference can be substantially suppressed.

  As described above, in the illumination optical devices (1 to 14) of the first embodiment, the aspect ratio changing unit including the first cylindrical lens pair 8 and the second cylindrical lens pair 9 is used to operate based on a simple 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 between the patterns in the two orthogonal directions is substantially reduced by using the illumination optical apparatus that can adjust the aspect ratio of the secondary light source formed on the illumination pupil as needed. Therefore, it is possible to perform highly accurate exposure that does not occur.

  In the first embodiment described above, the aspect ratio changing means is configured by the first cylindrical lens pair 8 and the second cylindrical lens pair 9. However, the present invention is not limited to this, and in general, a first optical element group composed of a pair of optical elements having rotationally asymmetric power and a second optical element group composed of a pair of optical elements having rotationally asymmetric power, Thus, the aspect ratio changing means can be configured. 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 configured to be rotatable about the optical axis. It is preferable that

  In the first embodiment described above, the aspect ratio changing means (8, 9) is arranged at the pupil of the afocal lens 5 or in the vicinity thereof. However, the present invention is not limited to this. For example, the aspect ratio changing means (in the vicinity of the entrance plane of the micro fly's eye lens 11 or a position substantially in the Fourier transform relationship with the illumination pupil or in the vicinity thereof is generally used. 8, 9) can also be arranged.

  In the first embodiment described above, the conical axicon system 7 as the changing means is arranged on the light source side of the aspect ratio changing means (8, 9). However, the irradiated portion of the aspect ratio changing means (8, 9) is irradiated. If the conical axicon system 7 is arranged on the surface side, it is possible to reduce the diameter of the aspect ratio changing means (8, 9).

  The aspect ratio changing means (first cylindrical lens pair 8 and second cylindrical lens pair 9) of the illumination optical apparatus (1-14) of the first embodiment described above is, for example, the illumination optical apparatus (1-14) or the projection optical system. When the PL has an aberration, it not only corrects that the secondary light source has a slightly vertically or horizontally long shape (asymmetric shape) but also, for example, an illumination optical device (1-14) or a projection. Due to the transmittance distribution characteristic of the optical system PL, the in-plane luminance distribution of the secondary light source is asymmetric (for example, the luminance distribution shape is different in two directions orthogonal to each other in the secondary light source surface, typically a saddle type The secondary light source shape may be slightly deformed into a vertically long or horizontally long shape so as to be equivalent to the in-plane luminance distribution of the rotationally symmetric secondary light source.

  Further, due to pupil aberration of the projection optical system PL, a vertical / horizontal difference in the image-side numerical aperture of the projection optical system PL occurs, and a vertical / horizontal difference (V / H difference) in line width occurs as a result of the mask pattern transfer. At this time, 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, the aspect ratio of the line width can be eliminated. Alternatively, when the in-image non-uniformity of the aspect ratio of the image-side numerical aperture of the projection optical system PL occurs, the aspect ratio changing means (the first cylindrical lens pair 8 and the second cylindrical lens pair 9) is appropriately controlled (sorted). Adjustment) to optimize the shape of the secondary light source, and as a result, the in-plane non-uniformity of the line width aspect can be reduced.

  Further, for example, due to the aberration and transmittance distribution characteristics of the illumination optical device (1-14) and the projection optical system PL, the in-plane luminance distribution of the secondary light source becomes asymmetric, and a plurality of in-illuminated surfaces When the in-plane luminance distribution of the secondary light source becomes non-uniform at the position, the in-plane luminance distribution of the secondary light source at a plurality of positions on the irradiated surface is symmetrical and uniform (approaching symmetrically and uniformly) As described above).

  For example, an illumination system luminance distribution measuring device disclosed in Japanese Patent Laid-Open No. 2000-19012 may be used 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. Here, measurement of the shape of the secondary light source or secondary for each illumination condition (secondary light source shape (circular, annular, multipolar), σ value, polarization degree, etc.) of the illumination optical device (1-14) It is preferable to measure the in-plane luminance distribution of the light source in advance and obtain the correction amount by the aspect ratio changing means (first cylindrical lens pair 8 and second cylindrical lens pair 9) for each illumination condition. Based on the obtained correction amount, the aspect ratio changing means (the first cylindrical lens pair 8 and the second cylindrical lens pair 9) is controlled when the illumination condition of the illumination optical device (1-14) is changed. For example, the shape of the secondary light source can be optimized individually for each illumination condition.

  In the first embodiment described above, when a vertical / horizontal difference (V / H difference) in the line width occurs as a result of the mask pattern transfer, 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, the vertical and horizontal differences in line width can be eliminated. This is because, when there is an asymmetry in the shape of the secondary light source or the in-plane luminance distribution of the secondary light source, a different factor from that when correcting the asymmetry of the secondary light source (for example, when applying a photosensitive material) (Including process conditions such as film thickness distribution and in-plane non-uniformity in exposure dose). It is a waste. In this case, correction is also considered in consideration of non-uniformity in the image plane of the vertical / horizontal difference of the line width.

  Further, the above-described adjustment of the shape of the secondary light source is typically performed at the time of manufacturing the illumination optical device (1 to 14), and thus at the time of manufacturing the projection exposure apparatus. However, when a user of the projection exposure apparatus sets conditions for projecting and exposing a mask pattern onto a wafer using the projection exposure apparatus, the shape of the secondary light source is adjusted in order to optimize the conditions. Also good. Further, 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 (1-14), and hence the projection exposure apparatus, the shape of the secondary light source Adjustments may be made. Further, for the purpose of improving the performance of the illumination optical device (1-14) and hence the projection exposure apparatus, the illumination optical device (1-14) and eventually some components of the projection exposure apparatus are readjusted and replaced. In this case, the secondary light source may be readjusted. Moreover, when setting a new illumination condition in the illumination optical device (1 to 14), the shape of the secondary light source may be adjusted to optimize the shape of the secondary light source with respect to the new illumination condition. .

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

  Referring to FIGS. 9 and 10, in the second embodiment, the aspect ratio changing means 15 comprising a pair of Fresnel lenses 15a and 15b is provided in the optical path between the bending mirror 3 and the diffractive optical element (4a, 4b). Has been placed. The Fresnel lenses 15a and 15b are optical elements each having a refractive function only in one direction. Further, 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, respectively.

  FIG. 11 is a diagram illustrating the action of a pair of Fresnel lenses on the 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 both set to coincide with the Z-axis direction. Therefore, in the vertical ellipse state shown in FIG. 11A, the light beam passing through the aspect ratio changing means 15 comprising the pair of Fresnel lenses 15a and 15b is not diverged in the X-axis direction but is diverged in the Z-axis direction. Thus, the illumination pupil is formed with a vertically elongated annular light source elongated in the Z direction.

  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 both set 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 comprising the pair of Fresnel lenses 15a and 15b is not diverged in the Z-axis direction but diverged in the X-axis direction. As a result, a horizontally elongated secondary light source elongated in the X direction is formed on the illumination pupil.

  Although not shown in the figure, the refractive direction of the first Fresnel lens 15a is set to coincide with the X-axis direction (or Z-axis direction), and the refractive direction of the second Fresnel lens 15b is set to the Z-axis direction (or X-axis). It can also be set to match (direction). In this perfect circle state, the light beam passing through the aspect ratio changing means 15 composed of the pair of Fresnel lenses 15a and 15b is subjected to the divergence action in the same manner in the Z-axis direction and the X-axis direction, and is not true for the illumination pupil. An annular belt-shaped secondary light source is formed.

  Similarly, also in 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 shown as a vertical ellipse shown in FIG. When set to the state, a vertically long circular secondary light source is formed on the illumination pupil, and when the aspect ratio changing means 15 is set to the horizontal elliptical state shown in FIG. A light source is formed. Furthermore, by setting an arbitrary state between the perfect circle state and the vertical ellipse state shown in FIG. 11A or an arbitrary state between the perfect circle state and the horizontal ellipse state shown in FIG. It is possible to form an annular or circular secondary light source according to various aspect ratios.

  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 orthogonal directions, and both optical elements have the optical axis AX. Each is configured to be rotatable around the center. 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 the light beam conversion element in two orthogonal directions. Thus, the aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil is configured.

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

  In the second embodiment described above, the first Fresnel lens 15a and the second Fresnel lens 15b constitute aspect ratio changing means. However, the present invention is not limited to this. In general, the first optical element having different divergence in two orthogonal directions and the second optical element having different divergence in two orthogonal directions are vertically and horizontally. Ratio changing means can also be configured. 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 preferably 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, or the aspect ratio changing means is constituted by a pair of microlens arrays having a refractive function only in one direction. You can also

  FIG. 12 is a drawing schematically showing a configuration of an exposure apparatus according to the third embodiment of the present invention. FIG. 13 is a diagram schematically showing the internal configuration of the aspect ratio changing means in 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. Is different. Hereinafter, the third embodiment will be described with a focus on differences from the second embodiment.

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

  The cylindrical zoom lens 16 is configured such that the interval along the direction of the optical axis AX between the cylindrical negative lens 16a and the cylindrical positive lens 16b can be changed. Further, in the cylindrical zoom lens 16, the cylindrical negative lens 16a and the cylindrical positive lens 16b are configured to be integrally rotatable about the optical axis AX. Note that 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 operate based on a command from the control system 21. This is performed by the drive system 29.

  FIG. 14 is a diagram for explaining the action of the cylindrical zoom lens on the secondary light source formed in the third embodiment. 14A and 14B show the optical path in the XY plane of the cylindrical zoom lens 16 in the rotational position state shown in FIG. 13, and FIGS. 14C and 14D show the rotational position shown in FIG. The optical path in the YZ plane of the cylindrical zoom lens 16 in the state is shown. As shown in FIG. 14A, in a perfect circle state (that is, an initial state where elliptical illumination is not performed), the image point Ia (virtual image) by the cylindrical negative lens 16a and the front focal point fb of the cylindrical positive lens 16b are matched. ing. In this case, the parallel light beam incident on the cylindrical zoom lens 16 is changed (enlarged) only in its diameter in the XY plane, and enters the diffractive optical element (4a, 4b) as the parallel light beam.

  Then, when only the cylindrical negative lens 16a is moved to the light source side along the optical axis direction from the perfect circle state shown in FIG. 14A and the interval is widened, as shown in FIG. 14B, the cylindrical positive lens 16b. Since the image point Ia by the cylindrical negative lens 16a moves away from the front focal point fb toward the light source side, the light beam incident on the diffractive optical elements (4a, 4b) is converted into a converged light beam in the XY plane. As shown in FIGS. 14C and 14D, in the YZ plane orthogonal to the XY plane, even in a perfect circle state corresponding to FIG. 14A, it corresponds to FIG. 14B. Even in the elliptical state, the parallel light beam incident on the cylindrical zoom lens 16 is incident on the diffractive optical element (4a, 4b) as the parallel light beam.

  FIG. 15 is a diagram showing a ring-shaped light intensity distribution obtained by the illumination pupil in a perfect circle state and an elliptical state of the cylindrical zoom lens. 15A shows the shape of the secondary light source (diffraction for annular illumination) formed in the illumination pupil in the circular state (initial state) of the cylindrical zoom lens 16 shown in FIGS. 14A and 14C. (B) is a diagram showing the light intensity distribution along the X direction of the secondary light source in the shape of a perfect annular zone in (a) (the vertical axis is the light intensity I). (C) is a figure which shows the light intensity distribution (the vertical axis | shaft is light intensity I) along the Z direction of the secondary light source of the perfect annular zone of (a).

  FIG. 14D 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. 14B and 14D (using the diffractive optical element 4a for annular illumination). (E) is a figure which shows the light intensity distribution along the X direction of the elliptical ring-shaped secondary light source of (d) (a vertical axis | shaft is light intensity I), (f) is a figure (d). It is a figure which shows the light intensity distribution (the vertical axis | shaft is light intensity | strength I) along the Z direction of the secondary light source of elliptical ring-shaped. As shown in FIG. 15C, the light intensity distribution along the X direction of the elliptical annular secondary light source obtained in the elliptical state is formed in the illumination pupil only by the action of the diffractive optical element 4a for annular illumination. And the light intensity distribution formed on the illumination pupil by the action of only the cylindrical zoom lens 16, resulting in two trapezoidal light intensity distributions in the X-direction cross section.

  In FIG. 15D, the hatched area (shaded area) in the figure is the area Im where the light intensity is maximum, and the light intensity gradient area Is where the light intensity gradually decreases is located around the area Im. . The elliptical zone-like light region indicated by the solid line in FIG. 15 (d) is wider in the X direction than the true-circle zone-like light region shown in FIG. 15 (a), but FIG. 15 (e) and FIG. When considered with reference to the 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 to the interval state shown in FIGS. 14A and 14C without depending on the rotational position of the cylindrical zoom lens 16. A secondary light source having a circular ring shape or a perfect circular shape is formed on the illumination pupil. Further, when the cylindrical zoom lens 16 is set to the first rotation position state shown in FIG. 13 and the cylindrical negative lens 16a and the cylindrical positive lens 16b are set to the interval state shown in FIGS. 14B and 14D, the illumination pupil is set. The secondary light source having an elliptical ring shape or an elliptical shape extending in the X direction is formed.

  Further, the cylindrical zoom lens 16 is set to the second rotational position state rotated by 90 degrees around the optical axis AX from the rotational position shown in FIG. 13, and the cylindrical negative lens 16a and the cylindrical positive lens 16b are set to FIG. When the interval state shown in (d) is set, an elliptical ring-shaped or elliptical secondary light source extending in the Z direction is formed on the illumination pupil. Furthermore, by setting an arbitrary state between the perfect circle state and the elliptical state in the first rotational position state and an arbitrary state between the perfect circle state and the elliptical state in the second rotational position state, various vertical and horizontal directions can be obtained. An annular or circular secondary light source according to the ratio can be formed.

  As described above, in the third embodiment, the cylindrical zoom lens 16 that can rotate around the optical axis AX is between the bending mirror 3 and the diffractive optical element (4a, 4b) as the light beam conversion element (and thus the light source 1). And the diffractive optical element (between 4a and 4b), the aspect ratio of the light intensity distribution formed on the illumination pupil is changed by independently changing the power in two orthogonal directions. The aspect ratio change means for making it correspond is comprised.

  As a result, in the third embodiment, as in the second embodiment, for example, the annular light source or the circular secondary light source is formed slightly vertically or horizontally, or the secondary light source is desired. If a line width difference of the pattern occurs in two orthogonal directions due to resist characteristics, etc., even if it is formed in an annular shape or a circular shape, the cylindrical zoom lens 16 that can rotate around the optical axis AX is used. The aspect ratio of the secondary light source can be adjusted at any time by the function of the aspect ratio changing means to substantially suppress the occurrence of the line width difference. If the pattern to be transferred has directionality, the aspect ratio of the secondary light source is adjusted at any time by the operation of the aspect ratio changing means 16 so that the annular or circular secondary light source is positively or vertically elongated. By setting to, 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 that can rotate 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, and two orthogonal directions A modification in which the aspect ratio changing means is configured by the second cylindrical zoom lens having a function of changing the power in the other direction 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 power in the Z direction, and a second having a function of changing power in the X direction. A cylindrical zoom lens 18 is used. The first cylindrical zoom lens 17 has a negative refractive power in the YZ plane and a non-refractive power cylindrical negative lens 17a in the XY plane, and a positive refractive power in the YZ plane and non-refractive in the XY plane. It is comprised with the cylindrical positive lens 17b of force.

  The second cylindrical zoom lens 18 has a negative refractive power in the XY plane and a non-refractive cylindrical negative lens 18a in the YZ plane, and a positive refractive power in the XY plane and in the YZ plane. It is configured by a non-refractive power cylindrical positive lens 18b. The first cylindrical zoom lens 17 is configured such that the interval along the direction of the optical axis AX between the cylindrical negative lens 17a and the cylindrical positive lens 17b can be changed.

  Similarly, the second cylindrical zoom lens 18 is configured so that the interval along the direction of the optical axis AX between the cylindrical negative lens 18a and the cylindrical positive lens 18b 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 lens 18 as appropriate, various aspect ratios are obtained based on the same principle as in the third embodiment. An annular or circular secondary light source can be formed.

  In the second embodiment and the third embodiment described above, the same control as the aspect ratio changing unit of the first embodiment may be performed.

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

  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 of wafers. Thereafter, in step 303, using the exposure apparatus of the present embodiment, the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot via the projection optical system. Thereafter, in step 304, the photoresist on the one lot of wafers is developed, and in step 305, the resist pattern is etched on the one lot of wafers to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each wafer.

  Thereafter, a device pattern such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer. According to the semiconductor device manufacturing method described above, a semiconductor device having an extremely fine circuit pattern can be obtained with high throughput. In steps 301 to 305, a metal is deposited on the wafer, a resist is applied on the metal film, and exposure, development, and etching processes are performed. Prior to these processes, on the wafer. It is needless to say that after forming a silicon oxide film, a resist may be applied on the silicon oxide film, and steps such as exposure, development, and etching may be performed.

  In the exposure apparatus of this 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 technique at this time will be described with reference to the flowchart of FIG. In FIG. 18, in a pattern forming process 401, a so-called photolithography process is performed in which a mask pattern is transferred and exposed to a photosensitive substrate (such as a glass substrate coated with a resist) using the exposure apparatus of the present embodiment. 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 steps such as a developing step, an etching step, and a resist stripping step, whereby 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 three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter forming step 402, a cell assembly step 403 is executed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like. In the cell assembling step 403, for example, 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) is obtained. ).

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

  In each of the above-described embodiments, the present invention has been described by taking the annular illumination and the circular illumination as an example. However, the present invention is not limited to this, and the present invention is also applied to, for example, quadrupole illumination and other modified illumination. Can be applied.

  Further, in each of the above-described embodiments, the present invention is applied to an illumination optical apparatus having a specific configuration as shown in FIG. 1. However, the present invention is not limited to this. For example, Japanese Patent Application Laid-Open No. 2003-68607 and The present invention is also applied to the embodiment of FIG. 10 of US Patent Application Publication No. US2003 / 0038931 corresponding to this and the embodiment of FIG. 1 of the international application number PCT / JP03 / 15447 and drawings. Is possible. Here, in the embodiment of FIG. 10 of Japanese Patent Application Laid-Open No. 2003-68607 and US Patent Application Publication No. US2003 / 0038931 corresponding thereto, two pairs of cylindrical lenses are formed by the zoom lens 4 and the fly-eye lens 5. It can arrange | position in the optical path between. In the embodiment of FIG. 1 of the international application number PCT / JP03 / 15447 and the drawings, two pairs of cylindrical lenses are placed in the optical path of the afocal lens 5 or between the zoom lens 7 and the fly-eye lens 5. It can be placed in the optical path.

  In each of the above-described embodiments, the present invention has been described by taking an exposure apparatus including an illumination optical apparatus as an example. However, the present invention is applied to a general illumination optical apparatus for illuminating an irradiated surface other than a mask. Obviously it can be done.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 4 Diffractive optical element 5 Afocal lens 7 Conical axicon system 8, 9 Cylindrical lens pair 10 Zoom lens 11 Micro fly eye lens 12 Condenser optical system 13 Mask blind 14 Imaging optical system 15a, 15b Fresnel lenses 16, 17, 18 Cylindrical zoom lens M Mask PL Projection optical system W Wafer 20 Input means 21 Control system 22-29 Drive system

Claims (20)

In the illumination optical device that illuminates the illuminated surface based on the light flux from the light source,
Aspect ratio changing means for changing the aspect ratio of the light intensity distribution formed on the illumination pupil substantially in a Fourier transform relationship with the illuminated surface,
The aspect ratio changing means includes an optical element group that is disposed at or near a position substantially in a Fourier transform relationship with the illumination pupil and has a function of changing a power ratio in two orthogonal directions. An illumination optical device. 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, and the first optical element group and The illumination optical apparatus according to claim 1, wherein at least one of the second optical element groups is configured to be rotatable about an optical axis. The illumination optical apparatus according to claim 1, wherein both the first optical element group and the second optical element group are configured to be rotatable about the optical axis. The illumination optical apparatus according to claim 1, wherein the optical element group is a lens group. Further comprising changing means for continuously changing the magnitude of the light intensity distribution formed in the illumination pupil,
5. The illumination optical apparatus according to claim 1, wherein the optical element group is disposed in an optical path closer to the light source than the changing unit. The changing means is a first changing means for changing an outer shape of a light intensity distribution formed on the illumination pupil, and a second changing means for changing an annular ratio of the light intensity distribution formed on the illumination pupil. The illumination optical apparatus according to claim 5, comprising: Changing means comprising: 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
5. The illumination optical apparatus according to claim 1, wherein the optical element group is disposed in an optical path closer to the light source than the changing unit. In the illumination optical device that illuminates the illuminated surface based on the light flux from the 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 in an illumination pupil substantially in a Fourier transform relationship with the illuminated surface, based on the light flux from the light flux 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 flux incident on the light flux conversion element in two orthogonal directions. An illumination optical apparatus comprising: The aspect ratio changing means includes a first optical element having different divergence levels in two orthogonal directions and a second optical element having different divergence levels in two orthogonal directions. 9. The illumination optical apparatus according to claim 8, wherein at least one of the element and the second optical element is configured to be rotatable about an axis parallel to the traveling direction of the light beam. 10. The illumination optical apparatus according to claim 8, wherein both the first optical element and the second optical element are configured to be rotatable about an axis parallel to a traveling direction of the light beam. 11. The illumination optical apparatus according to claim 9, wherein the first optical element and the second optical element each include a diffractive optical element having a diverging function only in one direction. The illumination optical apparatus according to claim 9 or 10, wherein the first optical element and the second optical element each include a Fresnel lens having a refractive function only in one direction. 11. The illumination optical apparatus according to claim 9, wherein the first optical element and the second optical element each include a microlens array having a refractive function only in one direction. The illumination optical apparatus according to claim 8, wherein the forming optical system includes an optical integrator. In the illumination optical device that illuminates the illuminated surface based on the light flux from the 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 in an illumination pupil substantially in a Fourier transform relationship with the illuminated surface, based on the light flux from the light flux conversion element;
In order to change the aspect ratio of the light intensity distribution formed in the illumination pupil by changing the power independently in two orthogonal directions arranged in the optical path between the light source and the light beam conversion element. An illumination optical apparatus comprising: an aspect ratio changing unit. 16. The illumination optical apparatus according to claim 15, wherein the aspect ratio changing unit includes a cylindrical zoom lens that is rotatable about an optical axis. The aspect ratio changing means changes the power in the first cylindrical zoom lens having a function of changing the power in one of the two orthogonal directions and the other of the two orthogonal directions. The illumination optical apparatus according to claim 15, further comprising: a second cylindrical zoom lens having a function of causing The illumination optical apparatus according to claim 15, wherein the forming optical system includes an optical integrator. In an exposure apparatus that transfers a mask pattern onto a photosensitive substrate,
The illumination optical apparatus according to any one of claims 1 to 18,
An exposure apparatus comprising: a projection optical system that projects the mask pattern set on the irradiated surface onto the photosensitive substrate. In an exposure method for transferring a mask pattern onto a photosensitive substrate,
Illuminating the mask set on the irradiated surface using the illumination optical apparatus according to any one of claims 1 to 18, and
And exposing the pattern of the mask onto the photosensitive substrate.

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