JP2001330964A - Exposure apparatus and microdevice manufacturing method using the exposure apparatus - Google Patents

Abstract

(57) Abstract: An exposure apparatus capable of substantially suppressing a change in optical characteristics of each projection optical unit due to light absorption of a lens. SOLUTION: An illumination system (IL) and a projection optical system (PL) having a plurality of projection optical units (PL1 to PL5) are provided, and the illumination system is substantially optically conjugate with a pupil plane of each projection optical unit. An exposure apparatus that forms a secondary light source at a position and projects and exposes a mask pattern onto a photosensitive substrate (P) via a projection optical system. The illumination system sets the light intensity distribution of the secondary light source to a light intensity distribution that is substantially higher at the periphery than at the center, in order to substantially control fluctuations in the optical characteristics of each projection optical unit due to light irradiation. And an intensity distribution setting means (9) for performing the setting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and a microdevice manufacturing method using the exposure apparatus, and more particularly, to a mask, a photosensitive substrate, and a projection optical system including a plurality of catadioptric projection optical units. The present invention relates to a multi-scan projection exposure apparatus for projecting and exposing a mask pattern on a photosensitive substrate while moving a mask.

[0002]

2. Description of the Related Art In recent years, liquid crystal display panels have been frequently used as display elements for word processors, personal computers, televisions, and the like. A liquid crystal display panel is manufactured by patterning a transparent thin-film electrode on a plate into a desired shape by a photolithography technique. As an apparatus for the photolithography process, a projection exposure apparatus that projects and exposes an original pattern formed on a mask to a photoresist layer on a plate via a projection optical system is used.

In recent years, there has been an increasing demand for a large-sized liquid crystal display panel, and with this demand, it has been desired to enlarge the exposure area in this type of projection exposure apparatus.
Therefore, in order to enlarge the exposure area, a so-called multi-scan type projection exposure apparatus has been proposed. In a multi-scan projection exposure apparatus, a mask pattern is projected and exposed on a plate while moving the mask and the plate with respect to a projection optical system including a plurality of projection optical units.

[0004]

By the way, in the multi-scanning type projection exposure apparatus configured as described above, the light supplied from the illumination system enters each projection optical unit via a mask. The light incident on each projection optical unit reaches the plate after passing through the lens of each projection optical unit. Part of the light reflected on the surface of the plate becomes return light and transmits through the lens of each projection optical unit again.

As described above, when the transmitted light of the mask and the reflected light of the plate pass through the lens of each projection optical unit, a part of the light is absorbed by the lens. As a result, the optical characteristics of each projection optical unit, particularly the position along the focusing direction of the imaging plane (hereinafter, referred to as “focus position”) may fluctuate due to light absorption of the lens constituting each projection optical unit. Can be considered.

The present invention has been made in view of the above-mentioned problems, and provides an exposure apparatus capable of substantially suppressing (controlling) fluctuations in optical characteristics of each projection optical unit due to light absorption of a lens. The purpose is to: Another object of the present invention is to provide a microdevice manufacturing method capable of manufacturing a good microdevice (semiconductor element, liquid crystal display element, thin film magnetic head, etc.) with a large area by good exposure using the exposure apparatus of the present invention. And

[0007]

According to a first aspect of the present invention, there is provided a method for illuminating a plurality of regions along a predetermined direction on a mask on which a pattern for transfer is formed. An illumination system, comprising: a projection optical system having a plurality of projection optical units arranged corresponding to a plurality of regions on the mask, wherein the illumination system is substantially optically conjugate with a pupil plane of each projection optical unit. An exposure apparatus that forms a secondary light source at a position and projects and exposes a pattern formed on the mask onto a photosensitive substrate through the projection optical system by guiding light from the secondary light source to the mask,
In order to substantially control the variation of the optical characteristics of each projection optical unit due to light irradiation, the illumination system changes the light intensity distribution of the secondary light source to a substantially higher light intensity distribution at the periphery than at the center. An exposure apparatus comprising an intensity distribution setting means for setting an exposure value.

According to a preferred aspect of the first invention, the mask and the photosensitive substrate are moved along the scanning direction intersecting with the predetermined direction with respect to the projection optical system, and the pattern formed on the mask is moved. Is scanned and exposed on the photosensitive substrate via the projection optical system. Preferably, the intensity distribution setting means sets the shape of the secondary light source in an annular shape. In this case, the intensity distribution setting means includes:
It is preferable to have a ring-shaped aperture stop having a ring-shaped aperture positioned at a position optically substantially conjugate with the pupil plane in the optical path of the illumination system.

According to a preferred embodiment of the first invention,
The intensity distribution setting means may be a conical prism for converting a circular incident light beam into an annular light beam in the optical path of the illumination system, or may convert the incident light beam into an annular light beam in the optical path of the illumination system. And a diffractive optical element for performing Further, the intensity distribution setting means controls the amount of fluctuation of the image plane of each projection optical unit along the focusing direction to an amount smaller than the depth of focus of each projection optical unit.
Preferably, the light intensity distribution of the secondary light source is set to a desired distribution. Further, in consideration of the influence of the flatness of the substrate and the like, it is desirable to set the amount to be smaller than 1/2 of the depth of focus.

Further, according to a preferred aspect of the first invention, the illumination system is configured such that an outer diameter of the secondary light source when converted to the pupil plane has a predetermined ratio with respect to an effective diameter of the pupil plane. Is also provided. In this case, it is preferable that the outer diameter setting means sets the outer diameter of the secondary light source when converted to the pupil plane larger than 0.7 times the effective diameter of the pupil plane. Also,
It is preferable that the outer diameter setting means has a diffractive optical element for enlarging the diameter of the incident light beam in the optical path of the illumination system. Further, the intensity distribution setting means and the outer diameter setting means, in order to control the amount of variation along the focusing direction of the imaging plane of each projection optical unit to an amount smaller than the depth of focus of each projection optical unit, It is preferable to set the light intensity distribution and the outer diameter of the secondary light source to a desired distribution and a desired outer diameter. Further, in consideration of the influence of the flatness of the substrate and the like, it is desirable to set the amount to be smaller than 1/2 of the depth of focus.

According to a second aspect of the present invention, there is provided an illumination system for illuminating a plurality of regions along a predetermined direction on a mask on which a transfer pattern is formed, and a plurality of regions corresponding to the plurality of regions on the mask. A projection optical system having a plurality of projection optical units arranged in a matrix, wherein the illumination system forms a secondary light source at a position optically substantially conjugate with the pupil plane of each projection optical unit, and An exposure system for projecting and exposing a pattern formed on the mask onto a photosensitive substrate via the projection optical system by guiding the light to the mask, Outer diameter setting means for setting the outer diameter of the secondary light source when converted to the pupil plane to be larger than 0.7 times the effective diameter of the pupil plane in order to substantially control the variation in characteristics. Having To provide an exposure apparatus characterized.

According to a preferred aspect of the second invention, the mask and the photosensitive substrate are moved along a scanning direction intersecting the predetermined direction with respect to the projection optical system, so that a pattern formed on the mask is formed. Is scanned and exposed on the photosensitive substrate via the projection optical system. Preferably, the outer diameter setting means has a diffractive optical element for enlarging the diameter of the incident light beam in the optical path of the illumination system.
Further, the outer diameter setting means controls the outside of the secondary light source in order to control the amount of variation of the imaging plane of each projection optical unit along the focusing direction to an amount smaller than the depth of focus of each projection optical unit. It is preferable to set the diameter to a desired outer diameter. Further, in consideration of the influence of the flatness of the substrate and the like, it is desirable to set the amount to be smaller than 1/2 of the depth of focus.

According to a third aspect of the present invention, there is provided an exposure apparatus having an illumination system for illuminating a mask on which a pattern for transfer is formed, and a projection optical system for projecting an image of the pattern of the mask onto a photosensitive substrate. The illumination system includes: a secondary light source forming unit configured to form a secondary light source at a position substantially conjugate to a pupil plane of the projection optical system; and the secondary light source according to a change in optical characteristics of the projection optical system. And an adjusting means for adjusting the light intensity distribution of the exposure light.

According to a preferred aspect of the third invention, the projection optical system has a plurality of projection optical units, and the illumination system sets a plurality of illumination areas corresponding to the plurality of projection optical units on the mask. Respectively, and the secondary light source forming means forms a plurality of secondary light sources corresponding to the plurality of illumination regions in order to guide light from the secondary light source to each of the plurality of illumination regions. Adjusting the light intensity distribution of at least one secondary light source of the plurality of secondary light sources according to a change in optical characteristics of at least one projection optical unit of the plurality of projection optical units. I do.

According to a fourth aspect of the present invention, there is provided an exposure step of exposing the photosensitive substrate to a pattern image of the mask using the exposure apparatus of the first to third aspects, and a developing step of developing the exposed substrate. And a method for manufacturing a microdevice.

According to a fifth aspect of the present invention, there is provided an illumination system for illuminating a plurality of areas along a predetermined direction on a mask on which a pattern for transfer is formed, and a plurality of areas corresponding to the plurality of areas on the mask. A projection optical system having a plurality of projection optical units arranged in a matrix, and an exposure apparatus for projecting and exposing a pattern formed on the mask onto a photosensitive substrate via the projection optical system. A light guide having at least one light source, as many incident ends as the number of light sources, and as many exit ends as the number of the projection optical units; and inputting light from the at least one light source to the light guide. At least one relay optical system for guiding to an end, and a position optically substantially conjugate with a pupil plane of each projection optical unit based on light beams emitted from a plurality of emission ends of the light guide. A plurality of optical integrators for respectively forming secondary light sources, a plurality of condenser optical systems for guiding light beams from the plurality of secondary light sources to a plurality of regions on the mask, and each projection by light irradiation An intensity distribution setting means for setting the light intensity distribution of the secondary light source to a light intensity distribution having a substantially higher intensity at the periphery than at the center, in order to substantially control the variation in the optical characteristics of the optical unit. An exposure apparatus characterized by comprising:

According to a preferred aspect of the fifth invention, the intensity distribution setting means has a ring-shaped aperture stop having a ring-shaped opening positioned on the emission side of the optical integrator. Further, the intensity distribution setting means may be a conical prism for converting a circular incident light beam into an annular light beam near the pupil plane of the relay optical system, or near a plurality of exit ends of the light guide. It is preferable to have a plurality of diffractive optical elements arranged to convert the incident light beam into an annular light beam.

Further, according to a preferred aspect of the fifth invention,
The light source includes an elliptical mirror and an ultra-high pressure mercury lamp positioned near a first focal point of the elliptical mirror, and the intensity distribution setting unit includes a maximum aperture of an incident light beam that can propagate through the light guide. The magnification of the relay optical system is set to be smaller than a predetermined magnification so that the numerical aperture of the light beam incident on the entrance end of the light guide is substantially equal to or larger than the number.

Further, according to a preferred aspect of the fifth invention, the illumination system is configured such that an outer diameter of the secondary light source when converted to the pupil plane is more than a predetermined ratio to an effective diameter of the pupil plane. An outer diameter setting means for setting a large value is further provided. In this case, it is preferable that the outer diameter setting means has a diffractive optical element arranged near the plurality of exit ends of the light guide for increasing the diameter of the incident light beam. Alternatively, the outer diameter setting means may adjust the magnification of the relay optical system such that the maximum numerical aperture of the incident light beam that can propagate through the light guide substantially matches the numerical aperture of the incident light beam at the incident end of the light guide. Is preferably set to a desired magnification.

According to a sixth aspect of the present invention, there is provided an illumination system for illuminating a plurality of regions along a predetermined direction on a mask on which a pattern for transfer is formed, and a plurality of regions corresponding to the plurality of regions on the mask. A projection optical system having a plurality of projection optical units arranged in a matrix, and an exposure apparatus for projecting and exposing a pattern formed on the mask onto a photosensitive substrate via the projection optical system. A light guide having at least one light source, as many incident ends as the number of light sources, and as many exit ends as the number of the projection optical units; and inputting light from the at least one light source to the light guide. At least one relay optical system for guiding to an end, and a position optically substantially conjugate with a pupil plane of each projection optical unit based on light beams emitted from a plurality of emission ends of the light guide. A plurality of optical integrators for respectively forming secondary light sources, a plurality of condenser optical systems for guiding light beams from the plurality of secondary light sources to a plurality of regions on the mask, and each projection by light irradiation To substantially control the variation in the optical characteristics of the optical unit, the outer diameter of the secondary light source when converted to the pupil plane is set to be larger than 0.7 times the effective diameter of the pupil plane. An exposure apparatus comprising: an outer diameter setting unit.

According to a preferred aspect of the sixth invention, the outer diameter setting means has a diffractive optical element arranged near a plurality of exit ends of the light guide for expanding the diameter of the incident light beam. preferable. Alternatively, the outer diameter setting means may adjust the magnification of the relay optical system such that the maximum numerical aperture of the incident light beam that can propagate through the light guide substantially matches the numerical aperture of the incident light beam at the incident end of the light guide. Is preferably set to a desired magnification.

According to a seventh aspect of the present invention, a plurality of regions along a predetermined direction are illuminated on a mask on which a pattern for transfer is formed, and a plurality of regions are arranged corresponding to the plurality of regions on the mask. In an exposure method for projecting and exposing a pattern formed on the mask onto a photosensitive substrate through a projection optical system having projection optical units, the projection optical unit is located at a position optically substantially conjugate with a pupil plane of each projection optical unit. Forming a secondary light source and illuminating a plurality of regions on the mask by guiding light from the secondary light source to the mask; and substantially changing the optical characteristics of each projection optical unit due to light irradiation. An intensity distribution setting step of setting the light intensity distribution of the secondary light source to a light intensity distribution having a substantially higher intensity at the periphery than at the center for control. That.

According to a preferred aspect of the seventh aspect, an outer diameter for setting the outer diameter of the secondary light source when converted to the pupil plane larger than a predetermined ratio with respect to the effective diameter of the pupil plane. Including a diameter setting step.

According to an eighth aspect of the present invention, a plurality of regions along a predetermined direction are respectively illuminated on a mask on which a pattern for transfer is formed, and a plurality of regions are arranged corresponding to the plurality of regions on the mask. In an exposure method for projecting and exposing a pattern formed on the mask onto a photosensitive substrate through a projection optical system having projection optical units, the projection optical unit is located at a position optically substantially conjugate with a pupil plane of each projection optical unit. Forming a secondary light source and illuminating a plurality of regions on the mask by guiding light from the secondary light source to the mask; and substantially changing the optical characteristics of each projection optical unit due to light irradiation. An outer diameter setting step of setting an outer diameter of the secondary light source when converted to the pupil plane to be larger than 0.7 times an effective diameter of the pupil plane for control. Provide a way .

According to a preferred aspect of the seventh and eighth aspects of the present invention, the mask and the photosensitive substrate are moved along the scanning direction intersecting the predetermined direction with respect to the projection optical system, so that the mask is An exposure step of scanning and exposing the formed pattern onto the photosensitive substrate via the projection optical system.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Generally, when light is applied to a lens, the temperature of an optical material forming the lens rises due to absorption of the light. As a result, the shape of the lens changes due to thermal expansion, and the refractive power changes. Further, when light is irradiated to the lens, the coarse density of the optical material forming the lens changes due to light absorption. As a result, the refractive index of the lens changes, and consequently its refractive power also changes.

An exposure apparatus according to a typical embodiment of the present invention includes an illumination system for illuminating a plurality of regions along a predetermined direction on a mask on which a transfer pattern is formed, and a mask. A projection optical system having a plurality of projection optical units arranged corresponding to the plurality of regions above. The illumination system is configured to form the secondary light source at a position optically substantially conjugate with the pupil plane of each projection optical unit.

In this case, an image of the secondary surface light source is formed on the pupil plane of each projection optical unit, and a light beam (zero-order transmitted light of the mask) incident on a lens disposed near the pupil plane. Is always constant without depending on the change in the size and shape of each illumination area on the mask (and, consequently, each exposure area on the photosensitive substrate). Further, in each projection optical unit, the fluctuation of the refractive power of the lens arranged near the pupil plane greatly contributes to the fluctuation of the optical characteristics of each projection optical unit, especially the fluctuation of the focus position. In particular, when using a multi-projection optical system,
It is assumed that the mask pattern density corresponding to the field of view of each projection optical unit is different. For example, in the case of a general mask pattern in which the amount of light guided to the projection optical unit at the end is considerably smaller than the amount of light guided to the projection optical unit at the center, the amount of change in the focus position is extremely large in the projection optical unit at the end. May be smaller,
By moving the position of the substrate in the direction of the optical axis for focusing, it becomes difficult to focus on all the projection optical units.

Based on the above findings, the inventors of the present invention
In order to satisfactorily suppress (control) fluctuations in the optical characteristics of each projection optical unit due to light absorption of the lens constituting each projection optical unit, particularly fluctuations in the focus position, the following 2
It has been found that one configuration is effective. That is, the first
Is to set the light intensity distribution of the secondary light source to a light intensity distribution having substantially higher intensity at the periphery than at the center, for example, an annular (annular) light intensity distribution. Also,
The second configuration is to set the outer diameter of the secondary light source when converted to the pupil plane larger than a predetermined ratio with respect to the effective diameter of the pupil plane.

According to the first configuration, the intensity of the light beam incident on the central portion of the lens disposed near the pupil plane of each projection optical unit may be greater than the intensity of the incident light beam on the peripheral portion. Be avoided. When the intensity of the light beam incident on the center of the lens is large, the temperature rise due to the light absorption of the lens is difficult to be uniform throughout the lens, and the refractive power of the lens tends to change. In other words, in the first configuration, for example, when a light beam having a ring-shaped light intensity distribution is made incident on a lens arranged near the pupil plane of each projection optical unit, a temperature rise due to light absorption of the lens causes an increase in the central portion. It is easy to be uniform with the peripheral part, and the fluctuation of the refractive power is favorably suppressed, and the fluctuation of the optical characteristics of each projection optical unit is favorably suppressed.

On the other hand, according to the second configuration, it is possible to avoid that the diameter of the light beam incident on the lens disposed near the pupil plane of each projection optical unit becomes significantly smaller than its effective diameter. When the diameter of the incident light beam is extremely small, due to a local shape change and a local refractive index change at the center of the lens,
The refractive power will change greatly. In other words,
In the second configuration, since the diameter of the light beam incident on the lens disposed near the pupil plane of each projection optical unit is relatively large as compared with its effective diameter, the fluctuation of the refractive power is favorably suppressed. Consequently, fluctuations in the optical characteristics of each projection optical unit are favorably suppressed.

As described above, according to the present invention, it is possible to realize an exposure apparatus capable of substantially suppressing a change in optical characteristics of each projection optical unit due to light absorption of a lens. Further, by performing good scanning exposure using the exposure apparatus of the present invention, for example, a high-precision liquid crystal display device or the like can be manufactured as a large-area good microdevice.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing an overall configuration of an exposure apparatus according to an embodiment of the present invention. Also,
FIG. 2 is a diagram schematically showing a configuration of an illumination system in the exposure apparatus of FIG. FIG. 3 is a diagram schematically showing a configuration of each projection optical unit constituting a projection optical system in the exposure apparatus of FIG.

In this embodiment, there is provided a multi-scan type projection exposure apparatus for projecting and exposing a mask pattern on a plate while moving the mask and the plate with respect to a projection optical system comprising a plurality of catadioptric projection optical units. The present invention is applied. 1 to 3, the X-axis is set along the direction (scanning direction) in which the mask on which a predetermined circuit pattern is formed and the plate on which the resist is applied are moved. The Y axis is set along a direction orthogonal to the X axis in the plane of the mask, and the Z axis is set along the normal direction of the plate.

The exposure apparatus of the present embodiment provides illumination for uniformly illuminating a mask M supported in parallel to the XY plane via a mask holder (not shown) on a mask stage (not shown in FIG. 1) MS. System IL. Referring to FIGS. 1 and 2, the illumination system IL includes a light source 1 formed of, for example, an ultra-high pressure mercury lamp. The light source 1 is positioned at a first focal position of an elliptical mirror 2 having a reflection surface formed of a spheroid. Therefore, the illumination light beam emitted from the light source 1 forms a light source image at the second focal position of the elliptical mirror 2 via the reflecting mirror (plane mirror) 3. At this second focal position, a shutter 4 (not shown in FIG. 1) is arranged.

The divergent light flux from the light source image formed at the second focal position of the elliptical mirror 2 forms an image again via the first relay lens system 5. In the vicinity of the pupil plane of the first relay lens system 5,
A wavelength selection filter 6 (not shown in FIG. 1) for transmitting only a light beam in a desired wavelength range is provided. In the wavelength selection filter 6, the g-line (436 nm) light and the h-line (40
5 nm) and i-line (365 nm) light are simultaneously selected as exposure light. The wavelength selection filter 6 can select, for example, g-line light and h-line light simultaneously, can select h-line light and i-line light simultaneously, and can further select i-line light. It is also possible to select only light.

The divergent light flux from the light source image formed via the first relay lens system 5 is re-imaged near the incident end 8a of the light guide 8 via the second relay lens system 7.
In the vicinity of the pupil plane of the second relay lens system 7, a conical prism (ring light forming member) 9 (not shown in FIG. 1) as an axicon is arranged. The conical prism 9 has a light source side surface (left surface in FIG. 2) formed in a conical concave shape toward the light source side, and a mask side surface (right surface in FIG. 2) toward the mask side. It is formed in a conical convex shape.

More specifically, the refracting surface on the light source side and the refracting surface on the mask side of the conical prism 9 correspond to a conical conical surface (side surface excluding the bottom surface) symmetrical with respect to the optical axis AX. They are configured to be substantially parallel to each other. Therefore, the circular luminous flux incident on the conical prism 9 is deflected at equal angles around the optical axis AX in all directions, and then converted into an orbicular (ie, annular) luminous flux. As described above, the conical prism 9 has a function of converting a circular light beam into an annular light beam.

On the other hand, the light guide 8 is a random light guide fiber formed by randomly bundling a large number of fiber strands, and has the same number of incident ends 8a as the number of light sources 1 (one in FIG. 1). And the same number of exit ends 8b as the number of projection optical units (five in FIG. 1) constituting the projection optical system PL.
To 8f (only the emission end 8b is shown in FIG. 2). In this way, the light incident on the incident end 8a of the light guide 8 propagates through the inside thereof, and then the five exit ends 8b to 8f
Emitted from.

The divergent light beam emitted from the light emitting end 8b of the light guide 8 is converted into a substantially parallel light beam by a collimating lens 10b (not shown in FIG. 1), and then a fly-eye integrator (optical integrator) 1
1b. Fly eye integrator 11b
Has a number of positive lens elements whose central axis is the optical axis A.
It is constituted by vertically and horizontally and densely arranged so as to extend along X. Therefore, the light beam incident on the fly-eye integrator 11b is wavefront-divided by a number of lens elements, and a secondary light source composed of the same number of light source images as the number of lens elements is formed on the rear focal plane (ie, near the exit surface). I do. That is, a substantial surface light source is formed on the rear focal plane of the fly-eye integrator 11b.

The light beam from the secondary light source is restricted by an aperture stop 12b (not shown in FIG. 1) arranged near the rear focal plane of the fly-eye integrator 11b.
The light enters the condenser lens system 13b. The aperture stop 12b is arranged at a position optically substantially conjugate with the pupil plane of the corresponding projection optical unit PL1, and has a variable aperture for defining the range of the secondary light source that contributes to illumination. The aperture stop 12b changes the aperture diameter of the variable aperture to change the σ value (projection optical system PL
Ratio of the aperture of the secondary light source image on the pupil plane to the aperture diameter of the pupil plane of each of the projection optical units PL1 to PL5 constituting
Is set to the desired value.

The light beam passing through the condenser lens system 13b illuminates the mask M on which a predetermined transfer pattern is formed in a superimposed manner. Similarly, the other exit end 8c of the light guide 8
The divergent light beam emitted from the light source 8 through 8f
0c-10f, fly eye integrator 11c-
The mask M is illuminated in a superimposed manner via an aperture stop 11f, aperture stops 12c to 12f, and condenser lens systems 13c to 13f. That is, the illumination system IL includes the mask M
A plurality (5 in total in FIG. 1) arranged in the Y direction above
Illuminate the trapezoidal region of

In the example described above, the illumination light from one light source 1 is equally divided into five illumination lights via the light guide 8 in the illumination system IL, but the number of light sources and the number of projection optical units Various modifications are possible without being limited to the number. That is, two or more light sources are provided as needed, and the illumination light from the two or more light sources is equally divided into a required number (the number of projection optical units) of illumination light via a light guide having good randomness. You can also. In this case, the light guide has the same number of entrance ends as the number of light sources, and has the same number of exit ends as the number of projection optical units.

The light from each of the illumination areas on the mask M is divided into a plurality (five in FIG. 1) of projection optical units PL 1 to P arranged in the Y direction so as to correspond to each of the illumination areas.
The light enters the projection optical system PL including L5. Here, the configuration of each of the projection optical units PL1 to PL5 is the same as each other. Hereinafter, the configuration of each projection optical unit will be described with reference to FIG.

The projection optical unit shown in FIG.
And a first imaging optical system K1 for forming a primary image of a mask pattern based on light from the primary image, and an erect image (secondary image) of the mask pattern formed on the plate P based on light from the primary image. A second imaging optical system K2. In the vicinity of the position where the primary image of the mask pattern is formed, a field stop FS that defines the field of view (illumination area) of the projection optical unit on the mask M and the projection area (exposure area) of the projection optical unit on the plate P Is provided.

The first image forming optical system K1 is located between the mask M and -Z.
A first right-angle prism PR1 having a first reflecting surface inclined at an angle of 45 ° with respect to the mask surface (XY plane) so as to reflect light incident along the direction in the −X direction is provided. Further, the first imaging optical system K1 includes a first right-angle prism P
In order from the R1 side, a first refractive optical system G having a positive refractive power
1P and a first concave reflecting mirror M1 having a concave surface facing the first right-angle prism PR1. The first refractive optical system G1P and the first concave reflecting mirror M1 are arranged along the X direction, and constitute a first catadioptric optical system HK1 as a whole. First
Light incident on the first right-angle prism PR1 from the catadioptric optical system HK1 along the + X direction is reflected by the second reflection surface inclined at an angle of 45 ° with respect to the mask surface (XY plane).
It is reflected in the Z direction.

On the other hand, the second imaging optical system K2 is provided on the plate surface (XY plane) so that light incident along the -Z direction from the second reflection surface of the first right-angle prism PR1 is reflected in the -X direction. A second right-angle prism PR2 having a first reflection surface inclined at an angle of 45 ° is provided. Also, the second
The imaging optical system K2 includes, in order from the second right-angle prism PR2 side, a second refractive optical system G2P having a positive refractive power, and a second concave reflecting mirror M2 having a concave surface facing the second right-angle prism PR2 side.
And The second refractive optical system G2P and the second concave reflecting mirror M2 are arranged along the X direction, and constitute the second catadioptric optical system HK2 as a whole. From the second catadioptric optical system HK2 along the + X direction, the second right-angle prism PR2
Incident on the plate surface (XY plane surface)
The light is reflected in the −Z direction by the second reflecting surface inclined at an angle of 5 °.

The mask M and the first right-angle prism PR1
In the optical path between the first reflecting surface and the field stop FS and the second reflecting surface.
In the optical path between the right-angle prism PR2 and the first reflecting surface,
Parallel plane plates P1 and P2 as image shifters are arranged, respectively. Here, the image shifter is means for translating (shifting) the position of an image formed on the plate P along the X direction and the Y direction. For this reason, the parallel plane plates P1 and P2 are configured to be rotatable around the X axis and around the Y axis in FIG.

As described above, the pattern formed on the mask M is illuminated by the illumination light (exposure light) from the illumination system IL with substantially uniform illuminance. Light traveling along the -Z direction from the mask pattern formed in each illumination area on the mask M passes through the parallel plane plate P1, and is deflected by 90 ° by the first reflection surface of the first right-angle prism PR1. ,
The light enters the first catadioptric optical system HK1 along the -X direction.

The light incident on the first catadioptric optical system HK1 passes through the first dioptric optical system G1P to the first concave reflecting mirror M1.
Reach The light reflected by the first concave reflecting mirror M1 again enters the second reflecting surface of the first right-angle prism PR1 along the + X direction via the first refractive optical system G1P. -Z is deflected by 90 ° on the second reflecting surface of the first right-angle prism PR1.
The light traveling along the direction forms a primary image of the mask pattern near the field stop FS. The lateral magnification of the primary image in the X direction is +1 times, and the lateral magnification in the Y direction is -1 times.

The light traveling along the -Z direction from the primary image of the mask pattern passes through the plane-parallel plate P2 and is deflected by 90 ° by the first reflecting surface of the second rectangular prism PR2, and is deflected in the -X direction. Along the second catadioptric optical system HK2. The light incident on the second catadioptric optical system HK2 is
The light reaches the second concave reflecting mirror M2 via the refractive optical system G2P. The light reflected by the second concave reflecting mirror M2 enters the second reflecting surface of the second right-angle prism PR2 along the + X direction again via the second refracting optical system G2P.

At the second reflecting surface of the second right-angle prism PR2, 9
The light deflected by 0 ° and traveling along the −Z direction forms a secondary image of the mask pattern on the corresponding exposure area on the plate P. Here, the lateral magnification of the secondary image in the X direction and the lateral magnification in the Y direction are both +1 times. That is, the plate P is projected via each projection optical unit.
The mask pattern image formed thereon is an equal-size erect image, and each projection optical unit constitutes an equal-size erect system.

In the above-described first catadioptric optical system HK1, the first concave reflecting mirror M1 is arranged near the rear focal position of the first dioptric system G1P. It is almost telecentric on the side.
Also, in the second catadioptric optical system HK2, the second concave reflecting mirror M2 is located near the rear focal position of the second dioptric optical system G2P.
Are arranged, so that they are almost telecentric on the field stop FS side and the plate P side. as a result,
Each projection optical unit is an optical system that is telecentric on substantially both sides (the mask M side and the plate P side).

Thus, a plurality of projection optical units PL1
Through the projection optical system PL composed of
On a plate stage (not shown in FIG. 1) PS, a mask pattern image is formed on a plate P supported in parallel with the XY plane via a plate holder. That is, as described above, since each of the projection optical units PL1 to PL5 is configured as a unity erecting system, a plurality of projection optical units PL1 to PL5 are arranged in the Y direction on the plate P, which is a photosensitive substrate, so as to correspond to each illumination area. In the trapezoidal exposure region, an equal-size erect image of the mask pattern is formed.

Incidentally, the mask stage MS is provided with a scanning drive system (not shown) having a long stroke for moving the stage along the X direction which is the scanning direction. Further, a pair of alignment driving systems (not shown) for moving the mask stage MS by a minute amount along the Y direction which is a scanning orthogonal direction and rotating the mask stage MS by a minute amount about the Z axis are provided. The position coordinates of the mask stage MS are measured and controlled by a laser interferometer MIF using a movable mirror.

A similar drive system is provided for the plate stage PS. That is, a scanning drive system (not shown) having a long stroke for moving the plate stage PS along the X direction which is the scanning direction, and moving the plate stage PS by a small amount along the Y direction which is the scanning orthogonal direction. In addition, a pair of alignment driving systems (not shown) for rotating by a minute amount around the Z axis are provided. The position coordinates of the plate stage PS are measured by a laser interferometer PIF using a movable mirror, and the position is controlled.

Further, as means for relatively positioning the mask M and the plate P along the XY plane,
A pair of alignment systems AL are arranged above the mask M. As alignment system AL, for example, mask M
Mask alignment mark and plate P formed on top
An alignment system of a method of obtaining a relative position with respect to a plate alignment mark formed thereon by image processing can be used.

Thus, the mask M and the plate P are moved to the projection optical system PL including the plurality of projection optical units PL1 to PL5 by the operation of the scan drive system on the mask stage MS side and the scan drive system on the plate stage PS side. By integrally moving in the same direction (X direction), the entire pattern region on the mask P is transferred (scanning exposure) to the entire exposure region on the plate P. The shape and arrangement of the plurality of trapezoidal exposure regions and the shape and arrangement of the plurality of trapezoidal illumination regions are described in detail in, for example, Japanese Patent Application Laid-Open No. 7-183212, and are duplicated. Is omitted.

In the present embodiment, as described above, since the conical prism 9 is disposed near the pupil plane of the second relay lens system 7, the circular light beam incident on the conical prism 9 becomes a substantially annular light beam. Is converted. Therefore, the light intensity distribution of the illumination field formed on the incident surface of each of the fly-eye integrators 11b to 11f becomes a distribution close to a ring shape, and a secondary light intensity distribution close to the ring shape is formed near the exit surface. A light source is formed. The images of the secondary light source having a light intensity distribution close to the annular shape are formed by the projection optical units PL1 to PL5.
Are formed in the vicinity of the pupil plane.

Thus, each of the projection optical units PL1 to PL
A light beam having a light intensity distribution close to an annular shape is incident on a lens arranged near the pupil plane of L5, that is, a lens arranged near the first concave reflecting mirror M1 and the second concave reflecting mirror M2. become. As a result, the temperature rise due to the light absorption of the lenses arranged near the pupil plane of each of the projection optical units PL1 to PL5 tends to be uniform between the central part and the peripheral part, and the fluctuation of the refractive power is favorably suppressed, Consequently, fluctuations in the optical characteristics of each projection optical unit, particularly fluctuations in the focus position, are favorably suppressed.

FIG. 4 is a diagram schematically showing a configuration of a main part of a first modification in which a ring-shaped aperture stop is used as each aperture stop in this embodiment. As shown in FIG.
When annular aperture stops 41b to 41f having annular apertures are used as 2b to 12f, the light intensity distribution of the secondary light source formed near the exit surface of each of the fly-eye integrators 11b to 11f is substantially circular. It is restricted to a band. In this case, a light beam having a substantially annular light intensity distribution enters the lenses arranged near the pupil plane of each of the projection optical units PL1 to PL5. Therefore, as compared with the case where only the conical prism 9 is used, the conical prism 9 is used.
When both the annular aperture stops 41b to 41f are used in combination with the annular aperture stops 41b to 41f, a light amount loss occurs in each of the annular aperture stops 41b to 41f, but the temperature rise due to light absorption tends to be uniform.

In this embodiment, annular aperture stops 41b to 41f can be used as the aperture stops 12b to 12f without using the conical prism 9.
In this case, the conical prism 9 and the annular aperture stops 41b to 41b
1f, the annular aperture stop 4
The light amount loss in 1b to 41f increases. However, since a light beam having a substantially annular light intensity distribution is incident on the lenses arranged near the pupil plane of each of the projection optical units PL1 to PL5, compared with the case where only the conical prism 9 is used. In addition, the temperature rise due to light absorption tends to be uniform.

By the way, as described above, in order to further suppress the fluctuation of the optical characteristics of each of the projection optical units PL1 to PL5, particularly the fluctuation of the focus position, if the secondary light source is annular, it is circular. Irrespective of the above, the outer diameter of the secondary light source when converted to the pupil plane of each of the projection optical units PL1 to PL5 is larger than a predetermined ratio to the effective diameter of the pupil plane (for example, 0% of the effective diameter of the pupil plane). .7 times larger)
It is preferable to set. Here, the outer diameter of the secondary light source when converted to the pupil plane means that the 0th-order transmitted light (transmitted light excluding the diffracted transmitted light) of the mask M corresponds to each of the projection optical units PL1 to PL.
5 is the outer diameter of the secondary light source image formed on the pupil plane.

In this case, each of the projection optical units PL1 to P
The diameter of the light beam incident on the lens arranged near the pupil plane of L5 is relatively large compared to its effective diameter. This means that the diameter of the light beam incident on the lens has a size corresponding to the outer diameter of the secondary light source when converted to the pupil plane, and the effective diameter of the lens has a size corresponding to the effective diameter of the pupil plane. Because. As a result, a large change in the refractive power due to a local shape change and a local refractive index change in the center of the lens is avoided, and a change in the optical characteristics of each of the projection optical units PL1 to PL5 causes a change in the focus position in particular. Is favorably suppressed.

In the present embodiment, in order to set the outer diameter of the secondary light source formed near the exit surface of each of the fly-eye integrators 11b to 11f to a required size, each of the fly-eye integrators 11b to 11f is required. It is necessary to set the outer diameter of the illuminated field formed on the incident surface of １１11f to a required size. In order to set the outer diameter of the illuminated field to a required size, each of the light emitting ends 8b to
It is necessary to set the numerical aperture of the light beam emitted from 8f to a required size. In the light guide 8, the numerical aperture of the incident light beam is stored and emitted. Therefore, in order to set the numerical aperture of the light beam emitted from the light guide 8 to a required size, the light beam incident on the incident end 8a of the light guide 8 is required. Must be set to a required size.

The numerical aperture of the light beam incident on the incident end 8a of the light guide 8 depends on the magnification of the second relay lens system 7. Specifically, when the magnification of the second relay lens system 7 is reduced, the numerical aperture of the light beam incident on the incident end 8a of the light guide 8 increases. On the other hand, the maximum numerical aperture of the incident light beam that can propagate inside the light guide 8 depends on the characteristics of the optical fiber constituting the light guide 8. Therefore, in the present embodiment, in order to set the outer diameter of the secondary light source formed near the exit surface of each of the fly-eye integrators 11b to 11f to a required size, the incident light flux that can propagate through the light guide 8 Is set to a certain value, and the magnification of the second relay lens system 7 is set to a desired value such that the maximum numerical aperture substantially matches the numerical aperture of the light beam incident on the incident end 8a of the light guide 8. What is necessary is just to set the magnification.

FIG. 5 is a diagram schematically showing a main configuration of a second modification in which a diffractive optical element is used instead of a conical prism to form an annular light beam in the present embodiment. In the second modified example, as shown in FIG. 5, near each of the emission ends 8b to 8f of the light guide 8, a diffractive optical element (DOE) is provided.
51b to 51f are respectively arranged. In other words, the diffractive optical elements 51b to 51f are arranged near the front focal positions of the collimating lenses 10b to 10f. Here, the diffractive optical elements 51b to 51f are formed by forming steps having a pitch about the wavelength of exposure light (illumination light) on a glass substrate, and have an action of diffracting an incident beam to a desired angle.

In the second modification, the diffractive optical element 51b
To 51f are ±± without substantially generating the zero-order transmitted light.
It is configured so that only the first-order diffraction transmitted light can be used. Therefore, through each of the diffractive optical elements 51b to 51f and each of the collimating lenses 10b to 10f, an almost annular illuminated field is formed on the incident surface of each of the fly-eye integrators 11b to 11f. A substantially annular secondary light source is formed. In addition, as described above, since the diffracted light passing through the diffractive optical elements 51b to 51f is used, the incident light flux is diffused by the diffractive optical elements 51b to 51f, so that the diameter thereof is enlarged. This is advantageous for setting the outer diameter of the annular secondary light source formed near the exit surfaces of the integrators 11b to 11f to be large.

In this sense, in the second modified example, the diffractive optical elements 51b to 51f can be configured to use the 0th-order transmitted light and ± 1st-order diffracted transmitted light. In this case, a circular secondary light source is formed near the exit surface of each of the fly-eye integrators 11b to 11f, but the outer diameter of the circular secondary light source is formed by the light-diffusion effect of the diffractive optical elements 51b to 51f. Is set large. In this case, similarly to the case where the annular secondary light source is formed via the diffractive optical elements 51b to 51f, each of the projection optical units PL1 to PL
The variation of the optical characteristic of No. 5 is particularly well suppressed. In the second modification, a ring-shaped aperture stop may be used together.

FIG. 6 is a diagram schematically showing a main configuration of a third modification of the present embodiment. In the third modified example, as shown in FIG. 6, a split lens group 61 and a lens 62 are arranged in the optical path between the first relay lens system 5 and the incident end 8a of the light guide 8. The split lens group 61 includes a first split lens 61a, a second split lens 61b, and a third split lens 61c in order from the light source side.
Each of the split lenses 61a to 61c is composed of four positive lens elements which are respectively arranged in regions divided by the Y axis and the Z axis around the optical axis AX.

The entrance surface of the first split lens 61a is positioned near the position where the light source image is formed via the first relay lens system 5. As shown in FIG. 6, the position where the light source image is formed via the first relay lens system 5 and the incident end 8a of the light guide 8 are substantially conjugated by the lens group 61 and the lens 62. . In other words, a light source image is formed at the incident end 8a of the light guide 8 as in the embodiment of FIG. As shown in FIG. 6, in the split lens group 61, light emitted from the optical axis AX near the entrance surface of the first split lens 61a is transmitted from the optical axis AX near the exit surface of the third split lens 61c. Converge at a remote location. On the other hand, light emitted from a position away from the optical axis AX near the entrance surface of the first split lens 61a is converged on the optical axis AX near the exit surface of the third split lens 61c.

When an ultra-high pressure mercury lamp is used as the light source 1, the numerical aperture of light emitted from the center of the light source image formed through the first relay lens system 5 (that is, the light emitted from the optical axis AX). The numerical aperture is substantially larger than the numerical aperture of light emitted from the periphery (that is, the numerical aperture of light emitted from a position distant from the optical axis AX). When the conical prism 9 is not provided in the embodiment of FIG. 2, each fly-eye integrator 11
The light intensity distribution of the circular secondary light source formed in the vicinity of the exit surfaces b to 11f is such that the intensity is highest at the center and decreases toward the periphery.

On the other hand, in the third modification, as shown in FIG. 6, light having a large numerical aperture emitted from the central portion of the light source image formed through the first relay lens system 5 is transmitted to the light guide 8. At a large angle of incidence. In this case, the angle at which the light from the central portion of the light source image is incident on the incident end 8a of the light guide 8 is set to be substantially larger than the angle corresponding to the maximum numerical aperture of the incident light beam that can propagate through the light guide 8. Part of the light from the central portion of the light source image does not propagate inside the light guide 8 and does not contribute to the formation of the secondary light source.

As a result, the light intensity distribution of the circular secondary light source formed near the exit surface of each of the fly-eye integrators 11b to 11f is changed to a light intensity distribution having substantially higher intensity at the periphery than at the center. can do. Thus, also in the third modified example, similarly to the case where the annular secondary light source is formed, the fluctuation of the optical characteristics of each of the projection optical units PL1 to PL5, particularly the fluctuation of the focus position, is favorably suppressed. In the third modification, a ring-shaped aperture stop can be used together.

FIG. 7 is a diagram schematically showing a main configuration of a fourth modification of the present embodiment. In the fourth modified example, as shown in FIG. 7, a deformed lens 71 is arranged in the optical path between the second relay lens system 7 and the incident end 8a of the light guide 8. The deformable lens 71 is a plano-convex lens having a plane directed toward the mask as a whole, as shown in an enlarged view in FIG. 7B, but the central portion of the lens surface on the light source side is partially flat. It has been transformed. Therefore, the central portion of the deformed lens 71 functions as a plane parallel plate, and the peripheral annular portion functions as a plano-convex lens.

As described above, in the fourth modification, the light having a large numerical aperture emitted from the central portion of the light source image formed via the first relay lens system 5 passes through the parallel flat plate constituting the central portion of the deformable lens 71. Through the incident end 8a of the light guide 8
Incident on the center of. On the other hand, a part of the light having a small numerical aperture emitted from the peripheral portion of the light source image formed via the first relay lens system 5 passes through the plano-convex lens constituting the peripheral portion of the deformable lens 71, and is transmitted to the optical axis AX. Is deflected to Therefore, the numerical aperture of the light beam incident on the periphery of the incident end 8a of the light guide 8 is increased by the action of the deformable lens 71.

As a result, in the light intensity distribution of the annular secondary light source formed in the vicinity of the exit surface of each of the fly-eye integrators 11b to 11f, the intensity on the inside decreases and the intensity on the outside increases. . In some cases, even without using the conical prism 9, the intensity inside the light intensity distribution of the circular secondary light source decreases and the intensity outside the light intensity distribution increases, and the intensity is substantially higher at the periphery than at the center. And a high light intensity distribution. Thus, also in the fourth modification,
Fluctuations in the optical characteristics of the projection optical units PL1 to PL5, particularly fluctuations in the focus position, are favorably suppressed. In the fourth modification, a ring-shaped aperture stop can be used together.

When an ultra-high pressure mercury lamp is used as the light source 1, as shown in FIG. 2, the reflection surface of the elliptical mirror 2 is partially lost at the center. Therefore, by reducing the magnification of the second relay lens system 7 and setting the numerical aperture of the light beam incident on the incident end 8a of the light guide 8 large, the vicinity of the exit surfaces of the fly-eye integrators 11b to 11f can be increased. The light intensity distribution of the formed secondary light source is affected by the central defect of the reflection surface of the elliptical mirror 2.

In other words, in some cases, even without using the conical prism 9, the intensity of the central portion of the circular secondary light source formed is reduced due to the central defect of the reflecting surface of the elliptical mirror 2. Thus, it is possible to obtain a circular secondary light source having a light intensity distribution substantially higher at the periphery than at the center. As a result, fluctuations in the optical characteristics of the projection optical units PL1 to PL5, particularly fluctuations in the focus position, are favorably suppressed. In this case, an annular aperture stop can be used together.

In the above-described embodiment, the amount of change in the focus position (the amount of change along the focusing direction of the imaging plane) of each of the projection optical units PL1 to PL5 is determined.
In order to suppress the focal depth to an amount smaller than 1/2 of the focal depth of L1 to PL5, it is preferable to set the light intensity distribution and the outer diameter of the secondary light source to a desired distribution and a desired outer diameter. In this case, each of the projection optical units PL1 to PL5 is located at an intermediate position in the range of variation of the focus position.
If the imaging planes of the projection optical units PL1 to PL5 are initialized, the scanning exposure can be repeated without substantially being affected by the fluctuation of the focus position of each of the projection optical units PL1 to PL5.

In the above-described embodiment, the present invention has been described by focusing on the change in the focus position of each of the projection optical units PL1 to PL5. However, other optical characteristics (aberration, magnification, image shift) due to the light absorption of the lens. , Image rotation, etc.) can be applied to the present invention. For example, even when a lens is not arranged near the pupil plane of each of the projection optical units PL1 to PL5, the suppression (control) of the fluctuation of the optical characteristics including the fluctuation of the focus position of each of the projection optical units PL1 to PL5 is also considered. Thus, the present invention is effective.

The optical member and each stage in the present embodiment shown in FIG. 1 are electrically, mechanically or optically connected so as to achieve the above-described functions, thereby achieving the exposure according to the present embodiment. The device can be assembled.
Then, the mask is illuminated by the illumination system IL (illumination step), and a transfer pattern formed on the mask is scanned and exposed on the photosensitive substrate using the projection optical system PL including the projection optical units PL1 to PL5 (exposure step). )
Microdevices (semiconductor elements, liquid crystal display elements, thin film magnetic heads, etc.) can be manufactured. Hereinafter, by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the present embodiment shown in FIG. 1,
An example of a technique for obtaining a semiconductor device as a micro device will be described with reference to the flowchart in FIG.

First, in step 301 of FIG.
A metal film is deposited on the wafers of the lot. In the next step 302, a photoresist is applied on the metal film on the l lot of wafers. Then, step 303
1, the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of the lot through the projection optical system (projection optical unit) using the exposure apparatus shown in FIG. Thereafter, in step 304, the photoresist on the one lot of wafers is developed, and in step 305, etching is performed on the one lot of wafers using the resist pattern as a mask, thereby forming a pattern on the mask. A corresponding circuit pattern is formed in each shot area on each wafer. Thereafter, a device such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer and the like. 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 the exposure apparatus shown in FIG. 1, 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). Less than,
An example of the technique at this time will be described with reference to the flowchart in FIG. In FIG. 9, a pattern forming step 4
In step 01, a so-called optical lithography step of transferring and exposing a mask pattern to 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 is subjected to various steps such as a developing step, an etching step, and a reticle peeling 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, three colors corresponding to R (Red), G (Green), and B (Blue)
Many sets of dots are arranged in a matrix,
Alternatively, a color filter in which a set of three stripe filters of R, G, and B are arranged in a plurality of horizontal scanning line directions is formed. Then, after the color filter forming step 402, a cell assembling step 403 is performed. 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, 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) is formed. ) To manufacture.

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 device, a liquid crystal display device having an extremely fine circuit pattern can be obtained with high throughput.

In the above-described embodiment, the present invention is applied to the multi-scan type projection exposure apparatus in which each projection optical unit has a pair of imaging optical systems, but each projection optical unit has one or three projection optical units. The present invention is also applicable to a multi-scan type projection exposure apparatus having the above-described imaging optical system.

In the above embodiment, the present invention is applied to the multi-scan projection exposure apparatus in which each projection optical unit has a catadioptric imaging optical system. However, the present invention is not limited to this. For example, the present invention can be applied to a multi-scan type projection exposure apparatus having a refraction type image forming optical system.

Further, in the above-described embodiment, an ultra-high pressure mercury lamp is used as a light source, but the present invention is not limited to this, and another appropriate light source can be used. That is, in the present invention, the exposure wavelength is not particularly limited to g-line, h-line, i-line and the like.

In the above-described embodiment, the present invention has been described with respect to a multi-scanning type projection exposure apparatus in which the projection optical system is composed of a plurality of projection optical units. However, in a general exposure apparatus, it is also effective in the present invention to measure a change in optical characteristics including a change in the focus position of the projection optical system and adjust the light intensity distribution of the secondary light source based on the measurement result. is there.

The intensity distribution setting means (cone prism, diffractive optical element, etc.) controls the amount of variation of the image plane of each projection optical unit along the focusing direction to an amount smaller than the depth of focus of each projection optical unit. For this reason, it is preferable to make the light intensity distribution of the secondary light source desirable, and furthermore, the intensity distribution setting means (cone prism, diffractive optical element, etc.) 1 / of depth of focus of optical unit
It is even more desirable to control the amount to less than two.
In this case, as an example, the numerical aperture N of each projection optical unit
Assuming that A is 0.1 and the exposure wavelength λ is 400 nm, the depth of focus DOF (= λ / (N
A ² )) is 40 μm. At this time, the undulation amount ΔP indicating a general plate flatness (AF control residue) is set to 10 μm.
m, Plate stage (holder) for holding plate
Assuming that the undulation amount ΔS indicating the flatness of the projection optical unit is 5 μm and the aberration amount △ A of the projection optical unit (including each module difference) is 5 μm, the allowable focus amount Fa (= DOF− △ P− △ S−
ΔA) is 20 μm. Therefore, in this example, 20 μ
It is preferable to control the amount to be smaller than m (１ ／ of the focal depth of each projection optical unit).

Now, a modification of the embodiment shown in FIG. 2 will be described with reference to FIG. The example shown in FIG. 10 shows each optical integrator (11b to 11b).
The intensity distribution of the secondary light source formed by f) is adjusted according to the fluctuation of the optical characteristics of each projection optical unit. 10 differs from the example shown in FIG. 2 in that a variable axicon 9, a variable aperture stop 12, and a measurement sensor DS are used.
(See FIG. 3), the control device CS, and each drive device (DR
9, DR12b to DR12f).

As shown in FIG. 10, the variable axicon 9
Has a concave conical prism 9a having a concave conical surface on the light source side and a convex conical prism 9b having a convex conical surface on the illuminated side. Then, by moving at least one of the two prisms in the optical axis direction, the diameter of the annular light flux is made variable (the ratio of the inner diameter of the annular light to the outer diameter of the annular light, that is, the annular ratio is variable). be able to. As a result, the diameter (ring zone ratio) of the ring-shaped secondary light source formed by the optical integrators (11b to 11f) changes.

Variable aperture stops (12b to 12f)
Is the setting of the variable luminous flux diameter of the axicon 9, that is, each of the optical integrators (11 b to 11 f).
The annular opening is changed in accordance with the diameter (ring zone ratio) of the annular secondary light source formed by the above, whereby the annular secondary light source is accurately defined. Here, the variable axicon 9 and the variable aperture stops (12b to 12f) are driven (movable) by the respective driving devices (DR9, DR12b to DR12f).

Next, the operation of the example shown in FIG. 10 will be briefly described. First, as shown in FIG. 3, changes in optical characteristics (focus, aberration, illuminance, telecentricity, etc.) of the projection optical unit are performed by using a measurement sensor DS as each projection measurement unit disposed at one end of the plate stage PS. Is measured (measuring process). Next, the control device CS calculates a light flux state capable of adjusting (correcting) the optical characteristics of each projection optical unit measured based on the output from the measurement sensor DS (calculation step), and based on the calculation result. The variable axicon 9 and the variable aperture stop (12b to 12c) in each illumination system via each drive device (DR9, DR12b to DR12f).
12f) is driven (variable) (adjustment step or correction step). Thereby, the pattern image of the mask M is projected and exposed on the photosensitive plate P under the good optical characteristics of each projection optical unit, so that a good mask pattern image can be formed on the plate P. Thus, a microdevice that is excellent in terms of quality can be manufactured.

The relay system 7 shown in FIG. 10 is constituted by a variable power optical system, and in order to change the light intensity distribution of the secondary light source, a part of the lens of the variable power relay system 7 is connected to the drive system DR9a. It is good also as a structure moved via. Further, the variable axicon 9 is not limited to the one that makes the annular luminous flux variable, but may be one that forms a multipolar luminous flux. In this case, for example,
The light source side of the prism 9a shown in FIG. 10 may be formed with a polygonal pyramid-shaped concave surface, and the prism 9b may be formed with a polygonal pyramid-shaped convex surface on the illuminated surface side. By relatively changing the distance between the two pyramidal prisms, it is possible to change the size of the multipolar secondary light source formed by the optical integrators (11b to 11f).
Needless to say, the fixed axicon 9 shown in FIG.
May also form a multipolar secondary light source,
In this case, it is preferable to form a polygonal refraction surface on the prism 9.

Each optical integrator (1
Adjusting the intensity distribution of the secondary light source formed by 1b to 11f) according to the fluctuation of the optical characteristics of each projection optical unit is not limited to the example shown in FIG. This can be achieved by making some changes. FIG. 11 shows a modification of the embodiment shown in FIG. 5, and the modification will be described with reference to FIG. 11 differs from the example shown in FIG. 5 in that a variable power optical system (variable collimating system) 10b, a variable aperture stop 12, and a measurement sensor DS are used.
(See FIG. 3), the control device CS, and each drive device (DR
10b and DR12b to DR12f).

As shown in FIG. 11, the variable magnification optical system 10b
Has at least two lenses (10b1, 10b2). Then, at least one of the lenses 10b2
By moving in the optical axis direction, the diameter of the annular light flux can be changed (the ratio of the inner diameter of the annular light to the outer diameter of the annular light, that is, the annular ratio can be changed). As a result, the diameter (ring zone ratio) of the ring-shaped secondary light source formed by the optical integrators (11b to 11f) changes.

Variable aperture stops (12b to 12f)
Is the setting of the annular luminous flux diameter of the variable magnification optical system 10b, that is, each optical integrator (11b to 11b).
The orbicular opening is changed according to the diameter (orbicular ratio) of the orbicular secondary light source formed by f), whereby the orbicular secondary light source is accurately defined. Here, the variable magnification optical system 10b and the variable aperture stop (12b to 12f)
Are the driving devices (DR10b, DR12b to DR12
driven (movable) by f).

Next, the operation of the example shown in FIG. 11 will be briefly described. First, as shown in FIG.
A change in optical characteristics (focus, aberration, illuminance, telecentricity, etc.) of the projection optical unit is measured using a measurement sensor DS as each projection measurement unit arranged at one end of S (measurement step). Next, the control device CS calculates a light flux state capable of adjusting (correcting) the optical characteristics of each projection optical unit measured based on the output from the measurement sensor DS (calculation step), and based on the calculation result. The variable magnification optical system 10b and the variable aperture stop (12b) in each illumination system via each drive device (DR10b, DR12b to DR12f).
12f) is driven (variable) (adjustment step or correction step). This allows the pattern image of the mask to be transferred to the photosensitive plate P under the favorable optical characteristics of each projection optical unit.
, A good mask pattern image can be formed on the plate P, and finally a good microdevice can be manufactured.

As an example shown in FIG. 11, an example is shown in which a diffractive optical element for forming an annular light beam (annular light intensity distribution) is used, but a circular light beam (circular light intensity) is used. Needless to say, a diffractive optical element for forming the distribution may be used. In this case, the optical characteristics of the projection optical unit can be adjusted (corrected) by the variable magnification optical system 10b.
It is preferable to adjust (correct) the diameter (size) of the circular secondary light source formed by each of the optical integrators (11b to 11f). In this case, the σ value (the numerical aperture of the illumination system / the numerical aperture of the projection optical unit, or the size (diameter) of the secondary light source at the pupil of the projection optical unit / the size (diameter) of the pupil of the projection optical unit) is Needless to say, it is preferable that the value be larger than 0.7. As described above, the fixed or variable axicon (cone prism, pyramid prism, etc.), the diffractive optical element (DOE), the fixed or variable annular aperture stop, and the like form a light intensity distribution with high intensity around the periphery. The element constitutes.

[0102]

As described above, according to the present invention,
It is possible to realize an exposure apparatus capable of substantially suppressing a change in optical characteristics of each projection optical unit due to light absorption of a lens. Further, by repeating desired scanning exposure using the exposure apparatus of the present invention, a high-precision liquid crystal display element, for example, as a good large-area microdevice can be manufactured.

[Brief description of the drawings]

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

FIG. 2 is a diagram schematically showing a configuration of an illumination system in the exposure apparatus of FIG.

FIG. 3 is a view schematically showing a configuration of each projection optical unit forming a projection optical system in the exposure apparatus of FIG. 1;

FIG. 4 is a diagram schematically showing a main configuration of a first modified example in which a ring-shaped aperture stop is used as each aperture stop in the present embodiment.

FIG. 5 is a diagram schematically showing a main configuration of a second modification in which a diffractive optical element is used instead of a conical prism to form a ring-shaped light beam in the present embodiment.

FIG. 6 is a diagram schematically showing a configuration of a main part of a third modification of the present embodiment.

FIG. 7 is a diagram schematically showing a configuration of a main part of a fourth modification of the embodiment.

FIG. 8 is a flowchart 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.

FIG. 9 is a flowchart of a method for obtaining a liquid crystal display element as a micro device by forming a predetermined pattern on a plate using the exposure apparatus of the present embodiment.

FIG. 10 is a diagram schematically showing a main configuration of a modification of the embodiment shown in FIG. 2;

11 is a diagram schematically showing a configuration of a main part of a modified example of the embodiment shown in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 light source 2 elliptical mirror 3 reflecting mirror 5 first relay lens system 7 second relay lens system 8 light guide 9 conical prism 10 collimating lens 11 fly-eye integrator 12 aperture stop 13 condenser lens system 41 annular aperture stop 51 diffractive optical element M mask PL projection optical system PL1 to PL5 projection optical unit P plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hitoshi Hatada 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72) Inventor Hiroshi Shirasawa 3-2-3 Marunouchi, Chiyoda-ku, Tokyo Nikon Corporation (72) Inventor Masahiro Iguchi 2-3-2 Marunouchi, Chiyoda-ku, Tokyo F-term in Nikon Corporation (Reference) 2H052 BA02 BA03 BA09 BA12 2H097 AA11 AB09 BB01 GB00 LA12 5F046 BA03 CB25 DA02 DB01 DB10

Claims (10)

[Claims] An illumination system for illuminating a plurality of regions along a predetermined direction on a mask on which a transfer pattern is formed, and a plurality of illumination systems arranged corresponding to the plurality of regions on the mask. A projection optical system having a projection optical unit, wherein the illumination system forms a secondary light source at a position optically substantially conjugate with a pupil plane of each projection optical unit, and transmits light from the secondary light source to the mask. An exposure apparatus for projecting and exposing a pattern formed on the mask onto a photosensitive substrate through the projection optical system by guiding the light, wherein the illumination system substantially changes the optical characteristics of each projection optical unit due to light irradiation. Light intensity distribution of the secondary light source, the light intensity distribution setting means for setting the light intensity distribution substantially higher in intensity at the periphery than at the center. Location. 2. A pattern formed on the mask is moved through the projection optical system by moving the mask and the photosensitive substrate along a scanning direction that intersects the predetermined direction with respect to the projection optical system. The exposure apparatus according to claim 1, wherein the photosensitive substrate is scanned and exposed. 3. The exposure apparatus according to claim 1, wherein the intensity distribution setting unit sets the shape of the secondary light source in an annular shape. 4. The apparatus according to claim 1, wherein the intensity distribution setting means has an annular aperture stop having an annular aperture positioned at a position optically substantially conjugate with the pupil plane in an optical path of the illumination system. The exposure apparatus according to claim 3, wherein 5. The apparatus according to claim 3, wherein the intensity distribution setting means has a conical prism for converting a circular incident light beam into an annular light beam in an optical path of the illumination system. Exposure equipment. 6. The exposure according to claim 3, wherein the intensity distribution setting means has a diffractive optical element for converting an incident light beam into a ring-shaped light beam in an optical path of the illumination system. apparatus. 7. An illumination system for illuminating a plurality of regions along a predetermined direction on a mask on which a pattern for transfer is formed, and a plurality of arrays arranged corresponding to the plurality of regions on the mask. A projection optical system having a projection optical unit, wherein the illumination system forms a secondary light source at a position optically substantially conjugate with a pupil plane of each projection optical unit, and transmits light from the secondary light source to the mask. An exposure apparatus for projecting and exposing a pattern formed on the mask onto a photosensitive substrate through the projection optical system by guiding the light, wherein the illumination system substantially changes the optical characteristics of each projection optical unit due to light irradiation. Outside diameter setting means for setting the outside diameter of the secondary light source when converted to the pupil plane larger than 0.7 times the effective diameter of the pupil plane. Characteristic exposure equipment . 8. An exposure apparatus comprising: an illumination system that illuminates a mask on which a pattern for transfer is formed; and a projection optical system that projects an image of the pattern of the mask onto a photosensitive substrate. Secondary light source forming means for forming a secondary light source at a position substantially conjugate with the pupil plane of the projection optical system, and adjusting a light intensity distribution of the secondary light source according to a change in optical characteristics of the projection optical system An exposure apparatus, comprising: an adjusting unit that performs adjustment. 9. The projection optical system includes a plurality of projection optical units, and the illumination system forms a plurality of illumination areas corresponding to the plurality of projection optical units on the mask, respectively. The light source forming unit forms a plurality of secondary light sources corresponding to the plurality of illumination regions to guide light from the secondary light source to each of the plurality of illumination regions. The light intensity distribution of at least one secondary light source of the plurality of secondary light sources is adjusted according to a change in optical characteristics of at least one of the projection optical units. 9. The exposure apparatus according to 8. 10. An exposure step of exposing the photosensitive substrate to a pattern image of the mask using the exposure apparatus according to claim 1, and a developing step of developing the exposed substrate. And a method for manufacturing a micro device.