JP2010014765A - Projection optical system, exposure device and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection/refraction type projection optical system, reducing the number of lenses to achieve a compact configuration and facilitating assembling adjustment. <P>SOLUTION: This reflection/refraction type projection optical system, which forms an image of a first area IF of a first plane MA on a second area EF of a second plane PT, includes: a first lens group G1 having positive refractive power; a curved reflecting surface CMa reflecting the light from the first area through the first lens group to the first plane side; a flat reflecting surface FMa reflecting the light reflected by the curved reflecting surface to the second plane side; and a second lens group G2 having positive refractive power and condensing the light reflected by the flat reflecting surface to the second area. The first lens group, the second lens group and the curved reflecting surface are disposed co-axially along one linear optical axis AX, and the flat reflecting surface is disposed eccentrically to the optical axis. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a projection optical system suitable for, for example, a scanning exposure apparatus that transfers a pattern to a photosensitive substrate.

  Liquid crystal display panels are frequently used as display devices such as televisions. The liquid crystal display panel is manufactured by patterning a transparent thin film electrode on a plate by a photolithography technique. As an apparatus for projecting and exposing a mask pattern onto a plate in the photolithography process, for example, a multi-lens scanning exposure apparatus (hereinafter referred to as “multi-scanning exposure apparatus”) is used. In a multi-scanning exposure apparatus, a mask pattern and projection exposure are performed on a plate while relatively moving a mask and a plate (photosensitive substrate) relative to a plurality of projection optical systems.

  In recent years, with an increase in the size of a liquid crystal display panel, both the plate and the mask tend to increase in size. The mask is expensive, and the cost increases due to the increase in size. Therefore, in order to avoid an increase in the size of the mask, a multi-scanning exposure apparatus has been proposed that enlarges and projects a mask pattern image onto a plate using a plurality of projection optical systems having a magnification (for example, patents). Reference 1).

JP 2007-286580 A

  In this case, if a refractive optical system is used as the projection optical system, it is difficult to suppress an increase in the number of lenses, the total length of the optical system, and the diameter of the optical system for aberration correction. On the other hand, when a catadioptric optical system is used as the projection optical system, although aberration can be corrected with a compact configuration with a reduced number of lenses, as shown in FIG. 2 of Japanese Patent Application Laid-Open No. 2004-271552, for example, One curved reflector is eccentrically arranged with respect to the optical axis. As a result, in a catadioptric projection optical system, it is difficult to position an optical member that is decentered with respect to the optical axis, and as a result, it is difficult to assemble and adjust the optical system.

  The present invention has been made in view of the above-described problems, and has a compact configuration with a reduced number of lenses and the like, and a catadioptric projection optical system, an exposure apparatus, and a device that can be easily assembled and adjusted. An object is to provide a manufacturing method.

In order to solve the above problems, in the projection optical system of the present invention, in the catadioptric projection optical system that forms an image of the first region of the first surface in the second region of the second surface,
A first lens group having a positive refractive power;
A curved reflecting surface that reflects light from the first region via the first lens group toward the first surface;
A planar reflecting surface that reflects the light reflected by the curved reflecting surface toward the second surface;
A second lens group having a positive refractive power and condensing the light reflected by the planar reflecting surface on the second region;
The first lens group, the second lens group, and the curved reflecting surface are arranged coaxially along one linear optical axis,
The planar reflecting surface is eccentrically arranged with respect to the one optical axis.

In the exposure apparatus of the present invention, in the exposure apparatus for transferring the image of the pattern of the mask placed on the mask stage to the photosensitive substrate placed on the substrate stage,
The projection optical system according to the present invention is provided,
The mask stage arranges the pattern on the first surface,
The substrate stage is characterized in that the photosensitive substrate is disposed on the second surface.

In the device manufacturing method of the present invention, using the exposure apparatus according to the present invention, an exposure step of transferring the pattern to the photosensitive substrate;
Developing the photosensitive substrate to which the pattern has been transferred, and forming a transfer pattern layer having a shape corresponding to the pattern on the photosensitive substrate;
And a processing step of processing the photosensitive substrate through the transfer pattern layer.

  In the projection optical system of the present invention, since the optical member having refractive power (or power) is arranged coaxially along one linear optical axis, assembly adjustment of the optical system is easy, and decentration aberrations are achieved. Can be satisfactorily suppressed. In addition, since the projection optical system of the present invention has a catadioptric optical system, aberrations can be favorably corrected with a compact configuration in which the number of lenses is suppressed. That is, according to the present invention, it is possible to realize a catadioptric projection optical system that has a compact configuration in which the number of lenses and the like are suppressed and that can be easily assembled and adjusted.

  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 an embodiment of the present invention. In the present embodiment, as shown in FIG. 1, the mask MA and the plate (photosensitive substrate) PT are moved relative to a plurality of (for example, four) projection optical systems PL1, PL2, PL3, and PL4 while moving relative to each other. The present invention is applied to a multi-scanning exposure apparatus 100 that projects and exposes an MA pattern onto a plate PT.

  The exposure apparatus 100 of the present embodiment includes an illumination apparatus IU that illuminates the pattern of the mask MA with illumination light from a light source, a mask stage MST that moves while holding the mask MA (only reference numerals are shown in FIG. 1), Stage drive including a projection optical device PLS that projects an enlarged image of the pattern of the mask MA onto the plate PT, a substrate stage PST that holds and moves the plate PT, a linear motor that drives the mask stage MST and the substrate stage PST, and the like. A mechanism DR and a main control system CR for comprehensively controlling operations of the stage drive mechanism DR and the like are provided.

  As an example, the plate PT is a 1.9 × 2.2 m square, 2.2 × 2.4 m square, 2.4 × 2.8 m square coated with a photoresist (photosensitive material) for manufacturing a liquid crystal display element, Or it is a rectangular and flat glass plate of about 2.8 × 3.2 m square. Further, as an example, the surface (photosensitive surface) of the plate PT is recognized by the main control system CR by dividing it into two pattern transfer areas EP1 and EP2 to which the pattern of the mask MA is transferred.

  Hereinafter, for ease of explanation, in FIG. 1, the scanning direction of the plate PT at the time of scanning exposure in the direction perpendicular to the guide surface (not shown) of the substrate stage PST in the direction parallel to the guide surface. Along the non-scanning direction perpendicular to the X axis in a plane parallel to the guide surface. For ease of explanation, the four projection optical systems PL1 to PL4 have the same configuration as each other, and are denoted by the reference symbol PL when not distinguished from each other. In the present embodiment, the guide surface of the substrate stage PST is parallel to the guide surface (not shown) of the mask stage MST, and the scanning direction of the mask MA during scanning exposure is parallel to the X axis. A rotation direction around an axis parallel to the Z axis is also referred to as a θz direction.

  In the illumination device IU, for example, illumination light (exposure light) for exposure is emitted from four (same number as the projection optical system) light transmission units of the light source unit. As the exposure light, light of i-line (wavelength 365 nm) selected from the light emitted from the ultra-high pressure mercury lamp is used. As the exposure light, for example, pulsed light composed of a third harmonic (wavelength 355 nm) of a YAG laser, g-line (wavelength 436 nm), h-line (wavelength 405 nm) and i-line (wavelength 365 nm) emitted from an ultrahigh pressure mercury lamp. ) Light having a wavelength selected from a wavelength region including light, or excimer laser light such as KrF (wavelength 248 nm) or ArF (wavelength 193 nm) can also be used.

  The illumination light emitted from the four light transmission units is arranged in four rows on the mask MA at intervals along the Y direction via corresponding four partial illumination optical systems (not shown). The illumination areas (illumination field areas) IF1, IF2, IF3, and IF4 are illuminated substantially uniformly. Each partial illumination optical system includes, for example, a collimator lens, a fly-eye lens, a condenser lens, a variable field stop, a relay optical system, and the like.

  Light from the illumination areas IF1 to IF4 of the mask MA passes through corresponding four projection optical systems PL1 to PL4, and trapezoidal exposure areas (image field areas or image fields) EF1, EF2, EF3 on the plate PT. EF4 is exposed. The projection optical systems PL1 to PL4 are telecentric on the mask MA side and the plate PT side, respectively, and have an enlargement magnification from the mask MA side to the plate PT side. The shapes of the exposure regions EF1 to EF4 are shapes obtained by enlarging the shapes of the illumination regions IF1 to IF4 with the projection magnification of the projection optical systems PL1 to PL4. The projection optical systems PL1 to PL4 and the exposure areas EF1 to EF4 corresponding to these are arranged in a line at intervals in the Y direction.

  In the present embodiment, the projection optical apparatus PLS is configured to include four projection optical systems PL1 to PL4, and the projection optical systems PL1 to PL4 respectively enlarge the patterns in the illumination areas IF1 to IF4 on the mask MA in common. Projection images enlarged at a magnification β are formed in the exposure regions EF1 to EF4 on the surface of the plate PT. The projection optical systems PL1 to PL4 form inverted images on the plate PT in the X direction (scanning direction) and the Y direction (non-scanning direction) of the pattern of the mask MA.

  Mask MA is sucked and held on mask stage MST via a mask holder (not shown). An X-axis movable mirror and a Y-axis movable mirror are fixed on the mask stage MST, and a mask-side laser interferometer comprising an X-axis laser interferometer and a Y-axis laser interferometer so as to face these movable mirrors. Is arranged. The mask side laser interferometer measures the X- and Y-direction positions of the mask stage MST and the rotation angle of the mask stage MST in the θz direction, and supplies the measurement results to the main control system CR. The main control system CR controls the position and speed of the mask stage MST in the X and Y directions and the rotation angle in the θz direction via a stage drive mechanism DR such as a linear motor based on the measured values.

  The plate PT is sucked and held on the substrate stage PST via a substrate holder (not shown). An X-axis moving mirror 51X and a Y-axis moving mirror 51Y are fixed to the substrate stage PST, and a laser interferometer 21XA that irradiates a measurement laser beam parallel to the X-axis so as to face the X-axis moving mirror 51X, 21XB, 21XC and auxiliary laser interferometer 21XD are arranged. Further, a laser interferometer 21YA and an auxiliary laser interferometer 21YB that irradiate a measurement laser beam parallel to the Y axis are arranged so as to face the Y-axis movable mirror 51Y.

  The X-axis and Y-direction positions of the substrate stage PST are measured by the X-axis laser interferometer 21XC and the Y-axis laser interferometer 21YA, and the substrate stage PST at the time of scanning exposure is measured by the laser interferometers 21XA and 21XB on both sides of the X-axis. The rotation angle in the θz direction is measured. Further, the rotation angle in the θz direction of the substrate stage PST when the substrate stage PST is stepped in the Y direction is measured by the Y-axis laser interferometer 21YA and the auxiliary laser interferometer 21YB. For example, when the straightness of the movable mirrors 51X and 51Y is good, only two laser interferometers (for example, 21XA and 21XB) of the X-axis laser interferometers 21XA to 21XD may be provided. The axial auxiliary laser interferometer 21YB can be omitted.

  The measurement values of the plate side laser interferometer composed of these laser interferometers 21XA to 21XD, 21YA, and 21YB are supplied to the main control system CR. The main control system CR controls the position and speed of the substrate stage PST in the X and Y directions via a stage drive mechanism DR such as a linear motor based on the measured values. At the time of scanning exposure, the substrate stage PST is driven at the speed V in the X direction in synchronization with the mask stage MST being driven at the speed V / β in the X direction. Since the images of the projection optical systems PL1 to PL4 are inverted in the X direction, the scanning direction of the mask stage MST and the scanning direction of the substrate stage PST are opposite to each other along the X axis. Further, since the image is also an inverted image in the Y direction, the pattern on the mask MA and the pattern formed on the plate PT are opposite in the X direction and the Y direction.

  In the vicinity of the projection optical systems PL1 to PL4, for example, an image processing type off-axis alignment system ALG for aligning the plate PT, and the position in the Z direction (focus position) of the mask MA and the plate PT are measured. An autofocus system (not shown) is arranged. Therefore, a plurality of alignment marks AM1 and AM2 are formed in the vicinity of the pattern transfer regions EP1 and EP2 on the plate PT, respectively. Further, based on the measurement result of the autofocus system, for example, control of the position of the mask stage MST in the Z direction and / or individual focus of the projection optical systems PL1 to PL4 using the Z drive mechanism in the stage drive mechanism DR. By driving a mechanism (not shown), the image planes of the projection optical systems PL1 to PL4 and the surface of the plate PT are focused.

  The substrate stage PST is provided with an aerial image measurement system 53 as an alignment system for measuring the position of the image of the position measurement mark on the mask MA projected through the projection optical systems PL1 to PL4. Yes. The detection signals of the alignment system ALG and the aerial image measurement system 53 are processed by an alignment signal processing system (not shown), and the position information of the test mark obtained by this processing is supplied to the main control system CR.

  FIG. 2 is a diagram schematically showing the basic configuration of the projection optical system according to the present embodiment. Referring to FIG. 2, the projection optical system PL of the present embodiment converts an image of the pattern of the illumination area (first area) IF of the pattern surface (first surface) of the mask MA onto the surface (second surface) of the plate PT. This is a catadioptric optical system formed in the exposure area (second area) EF. The projection optical system PL includes a first lens group G1 having a positive refractive power, a curved reflecting surface CMa that reflects light from the illumination area IF via the first lens group G1 toward the mask MA, and a curved surface. A planar reflecting surface FMa that reflects the light reflected by the reflecting surface CMa toward the plate PT side, and a first light that has positive refractive power and that reflects the light reflected by the planar reflecting surface FMa in the exposure area EF. 2 lens group G2.

  The first lens group G1, the second lens group G2, and the curved reflecting surface CMa (and thus the curved reflecting mirror CM having the curved reflecting surface CMa) are arranged coaxially along one linear optical axis AX. The planar reflecting surface FMa (and thus the planar reflecting mirror FM having the planar reflecting surface FMa) is eccentrically arranged with respect to the optical axis AX. Here, being arranged eccentrically means being arranged at a position that does not intersect the optical axis AX. The curved reflection surface CMa is disposed in the vicinity of a surface conjugate with the exit pupil (or entrance pupil) of the projection optical system PL, and this curved reflection surface CMa (and thus the curved reflection surface CMa is the same). The reflection member provided acts as an aperture stop.

  In the projection optical system PL of the present embodiment, all optical members having refractive power (or power) are arranged coaxially along one linear optical axis AX in one lens barrel VA. As with a single-lens barrel type refractive optical system, the assembly and adjustment of the optical system is easy, and the occurrence of decentration aberrations can be satisfactorily suppressed. In addition, since the projection optical system PL of the present embodiment has the form of a catadioptric optical system, it is possible to correct aberrations favorably with a compact configuration with a reduced number of lenses. That is, in the present embodiment, it is possible to realize a catadioptric projection optical system that has a compact configuration with a reduced number of lenses and the like and can be easily adjusted in assembly.

  In the projection optical system PL of the present embodiment, the planar reflecting surface FMa is eccentrically arranged with respect to the optical axis AX. However, since the reflecting surface FMa has no power, for example, the reflecting surface FMa is positioned in the X direction. Even if an error occurs, no decentration aberration occurs due to this positioning error. On the other hand, for example, in a conventional catadioptric optical system in which the second curved reflector is arranged eccentrically with respect to the optical axis, it is necessary to secure an optical path of light from the pattern surface (necessity of optical path separation). It is difficult to position the second curved reflecting mirror having a semi-chip shape with respect to the optical axis (and consequently assembly adjustment of the optical system), and decentration aberrations are likely to occur due to positioning errors of the second curved reflecting mirror.

  In each embodiment described later, the curved reflecting surface CMa is a concave reflecting surface on the mask MA side. That is, in each embodiment, the curved reflecting mirror CM is a concave reflecting mirror. In each embodiment, the planar reflecting surface FMa is arranged perpendicular to the optical axis AX. In each embodiment, the projection optical system PL forms an enlarged image of the pattern of the trapezoidal illumination area IF of the mask MA in the trapezoidal exposure area EF of the plate PT.

The projection optical system of the present invention is suitable for magnification projection of 1.5 to 3 times. That is, it is preferable that the following conditional expression (1) is satisfied for the magnification β.
1.5 <β <3 (1)

  If the upper limit of conditional expression (1) is exceeded, the focal length of the first lens group G1 is shortened and the refractive power is increased, so that the incident angle of light to the curved reflector CM is increased, and pupil aberration and image plane are increased. Demerits such as an increase in curvature occur. On the other hand, if the lower limit value of conditional expression (1) is not reached, the projection magnification becomes close to the same magnification (1 time), which is advantageous in terms of aberration correction, but the effect of enlarging the projected image is suppressed. For this reason, the effect of suppressing the enlargement of the mask MA in the exposure apparatus 100 is reduced.

In the projection optical system PL of this embodiment, the focal length of the first lens group G1 is f, the distance along the optical axis AX between the curved reflecting surfaces CMa a planar reflecting surface FMa and d _m It is preferable that the following conditional expression (2) is satisfied.
0.7 <d _m / f <1 (2)

  If the upper limit value of conditional expression (2) is exceeded, it is easy to avoid interference between the light beam traveling from the planar reflecting surface FMa toward the second lens group G2 and the curved reflecting mirror CM, but to the curved reflecting mirror CM. The incident angle of the light increases, and disadvantages such as an increase in pupil aberration occur. On the contrary, if the lower limit of conditional expression (2) is not reached, the incident angle of light to the curved reflecting mirror CM becomes small, which is advantageous in terms of aberration correction, but from the planar reflecting surface FMa to the second lens group G2. It becomes difficult to avoid the interference between the light beam traveling toward the curved surface and the curved reflecting mirror CM. In order to perform good aberration correction while avoiding optical path interference of the curved reflector CM, it is more preferable to set the lower limit value of conditional expression (2) to 0.9.

  In the present embodiment, the first lens group G1 preferably includes a negative lens group G1n and a positive lens group G1p in the order of incidence of light from the illumination area IF of the mask MA. With this configuration, correction of curvature of field is mainly advantageous, and the height of the light beam incident on the plane including the planar reflection surface FMa can be increased. As a result, it becomes easy to avoid interference between the incident light beam from the first lens group G1 to the curved reflecting surface CMa and the planar reflecting surface FMa, and it is easy to widen the field of view (exposure region). Further, when the first lens group G1 includes a negative lens group G1n and a positive lens group G1p in the order of incidence of light and adopts a so-called retrotype arrangement, the first lens group G1 is satisfied by satisfying conditional expression (2). It is easy to avoid interference between the surface on the plate PT side and the planar reflecting surface FMa.

When the first lens group G1 includes the negative lens group G1n and the positive lens group G1p in the light incident order, the focal length of the first lens group G1 is f, the focal length of the negative lens group G1n is f1, When the focal length of the lens group G1p is f2, it is preferable that the following conditional expression (3) is satisfied.
0.5 <(| f1 | / f2) / (f / (f−f2)) <1 (3)

  If the upper limit of conditional expression (3) is exceeded, the refractive power of the negative lens group G1n becomes too weak, and it becomes difficult to correct the field curvature well. In addition, it becomes difficult to separate the optical path of light from the first lens group G1 and the planar reflecting surface FMa, and the field of view needs to be narrowed. On the other hand, if the lower limit of conditional expression (3) is not reached, the refractive power of the negative lens group G1n becomes too strong, and aberrations according to image height such as field curvature and distortion (distortion aberration) deteriorate. As a result, in order to suppress these aberrations, the distance between the negative lens group G1n and the positive lens group G1p must be increased, and the overall length of the projection optical system is increased.

  In addition, the projection optical system PL of the present embodiment is disposed between the curved reflecting surface CMa and the planar reflecting surface FMa along the optical axis AX and coaxially with the curved reflecting surface CMa. It is preferable to include a third lens group G3 having a negative lens Ln at the end of the reflecting surface CMa. With this configuration, the overall refractive power distribution of the optical system can be easily performed. By disposing the negative lens Ln in the vicinity of the curved reflecting surface CMa, mainly correction of chromatic aberration and correction of spherical aberration can be effectively performed.

  The light from the illumination area IF of the mask MA is incident on the curved reflecting surface CMa via the negative lens Ln, and the light reflected by the curved reflecting surface CMa is planarly reflected via the negative lens Ln. The light incident on the surface FMa and reflected by the planar reflecting surface FMa enters the second lens group G2 via the negative lens Ln. In this way, the third lens group G3 is formed because the light from the illumination area IF of the mask MA passes through the third lens group G3 including the negative lens Ln three times before reaching the exposure area EF of the plate PT. By effectively using the refractive power of each lens, it is possible to reduce the number of lenses in the entire optical system.

  In each of the embodiments described below, the surface of the plate PT is provided with a circle 31 having a radius Ra centered on the optical axis AX and a distance Rb spaced from the optical axis AX by a distance Rb, as shown in FIG. An effective imaging region 33 defined by the straight line 32 extending in the direction is secured. Here, the “effective imaging area” means an area in which the aberration is corrected to a desired state on the image plane of the projection optical system PL. Therefore, due to the action of the variable field stop in the illuminating device IU, the trapezoidal exposure area EF having the base length La, the top side length Lb, and the height Lc is formed in the effective imaging area 33. Is set. In each embodiment, the radius Ra (that is, the maximum image height) is 142 mm, the distance Rb is 85 mm, the base length La is 226 mm, the top side length Lb is 190 mm, and the height Lc is 20 mm. It is. A trapezoidal illumination area IF (not shown) spaced from the optical axis AX is formed on the pattern surface of the mask MA so as to correspond to the trapezoidal exposure area EF spaced from the optical axis AX. Is done.

  That is, as shown in FIG. 4, a trapezoidal exposure area EF2 is formed on the photosensitive surface of the plate PT corresponding to the second projection optical system PL2, and a trapezoidal illumination area IF2 is formed on the pattern surface of the mask MA. Is formed. Similarly, a trapezoidal exposure area EF3 is formed on the photosensitive surface of the plate PT corresponding to the third projection optical system PL3 arranged at a distance in the Y direction from the second projection optical system PL2, and the mask MA A trapezoidal illumination area IF3 is formed on the pattern surface. FIG. 4 shows only the exposure area and the illumination area corresponding to the second projection optical system PL2 and the third projection optical system PL3, but the same applies to the other projection optical systems PL1 and PL4. In FIG. 4, in order to facilitate understanding of the description, the mask MA, the projection optical system PL, and the plate PT are displaced from each other along the X direction so as not to overlap.

  Hereinafter, in order to simplify the description, the shape and size of each exposure area are the same, and the opposite hypotenuses of two adjacent exposure areas are adjacent to the line segment connecting the midpoints of the pair of hypotenuses of each exposure area. The line segments connecting the midpoints are set to the same length Ld (see also FIG. 3; Ld = 208 mm in each embodiment). In this case, by the first scanning exposure in which the mask MA is moved in the + X direction as indicated by the arrow MD and the plate PT is moved in the −X direction as indicated by the arrow PD, for example, about half of the first transfer region EP1 is obtained. Area projection exposure is performed. Next, after the plate PT is moved stepwise in the Y direction by a distance Ld, the mask MA is moved in the −X direction opposite to the direction indicated by the arrow MD and the plate PT is moved in the direction opposite to the direction indicated by the arrow PD. Projection exposure of the remaining area of the first transfer area EP1 is performed by the second scanning exposure moved in the + X direction. Various modifications can be made to the shape, size, arrangement, etc. of each exposure region. Details of each embodiment will be described below.

In each embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangential plane at the apex of the aspheric surface to the position on the aspheric surface at height y. ) Is z, the apex radius of curvature is r, the conic coefficient is κ, and the nth-order aspheric coefficient is C _n , it is expressed by the following formula (a). In Tables (1) and (2), which will be described later, an aspherical lens surface is marked with an asterisk (*) on the right side of the surface number.
z = (y ² / r) / [1+ {1− (1 + κ) · y ² / r ² } ^1/2 ] + C ₄ · y ⁴ + C ₆ · y ⁶
+ C ₈ · y ⁸ + C ₁₀ · y ¹⁰ + C ₁₂ · y ¹² + C ₁₄ · y ¹⁴ (a)

[First embodiment]
FIG. 5 is a diagram showing a lens configuration of the projection optical system according to the first example of the present embodiment. In the projection optical system PL of the first example, the first lens group G1 includes a negative lens L11 and three positive lenses L12, L13, and L14 in the order of incidence of light from the trapezoidal illumination area IF of the mask MA. It is configured. The third lens group G3 includes a positive lens L31 and a negative lens L32 in the order of incidence of light from the first lens group G1. The second lens group G2 includes a positive lens L21, a negative lens L22, two positive lenses L23 and L24, and a plane parallel plate L25 in the order of incidence of light from the third lens group G3.

  In the first embodiment, the planar reflecting surface FMa is configured as the reflecting surface of the planar reflecting mirror FM, and the curved reflecting surface CMa is configured as the reflecting surface of the concave reflecting mirror CM. In the first lens group G1, the negative lens L11 forms a negative lens group G1n, and the three positive lenses L12, L13, and L14 form a positive lens group G1p. In the third lens group G3, the negative lens L32 constitutes a negative lens disposed in the vicinity of the curved reflecting surface CMa at the end of the third lens group G3. The curved reflecting surface CMa of the concave reflecting mirror CM acts as an aperture stop.

  In the first example, the light from the trapezoidal illumination area IF of the mask MA is reflected by the curved reflecting surface CMa of the concave reflecting mirror CM through the first lens group G1 and the third lens group G3 in order. The light is reflected by the reflecting surface FMa of the plane reflecting mirror FM through the three lens groups G3. The light reflected by the plane reflecting mirror FM sequentially passes through the third lens group G3 and the second lens group G2, and then forms an enlarged image of the pattern in the illumination area IF in the trapezoidal exposure area EF of the plate PT. .

  In the following table (1), values of specifications of the projection optical system PL according to the first example are listed. In the main specifications of Table (1), λ is the center wavelength of the exposure light, β is the size (absolute value) of the projection magnification from the mask MA of the projection optical system PL to the plate PT, and NA is the image side (plate (PT side) The numerical aperture is shown respectively. In the optical member specifications of Table (1), the surface number is the order of the surfaces from the light incident side, r is the radius of curvature of each surface (vertical curvature radius: mm in the case of an aspheric surface), d Represents the axial distance between the surfaces, that is, the distance (mm) along the optical axis from the surface to the next surface, and n represents the refractive index of the medium with respect to the center wavelength. Note that the sign of the surface distance d and the refractive index n are changed each time the light is reflected. The notation in Table (1) is the same in the following Table (2).

Table (1)
(Main specifications)
λ = 365nm
NA = 0.054
β = 2.5

Surface number rd n Optical member object surface ∞ 22.35362 1
1 -874.40638 28.44099 1.4745570 L11
2 * 1260.99850 11.33526 1
3 481.42856 20.00000 1.4876040 L12
4 -597.56435 2.20000 1
5 1602.66850 24.02300 1.4876040 L13
6 -222.34652 2.00000 1
7 -612.86436 20.00000 1.4876040 L14
8 -252.71098 34.10374 1
9 * -848.67204 45.00000 1.4745570 L31
10 -701.51462 96.25879 1
11 546.14698 31.79490 1.4745570 L32
12 454.90025 17.46809 1
13 ∞ 0.00000 1 (Aperture stop)
14 -466.46853 -17.46809 -1 CM
15 454.90025 -31.79490 -1.4745570 L32
16 546.14698 -96.25879 -1
17 -701.51462 -45.00000 -1.4745570 L31
18 * -848.67204 -14.10374 -1
19 ∞ 14.10374 1 FM
20 * -848.67204 45.00000 1.4745570 L31
21 -701.51462 96.25879 1
22 546.14698 31.79490 1.4745570 L32
23 454.90025 105.98173 1
24 1212.43910 30.00000 1.4745570 L21
25 17588.05800 3.10848 1
26 559.22273 38.43000 1.4745570 L22
27 446.57657 29.81434 1
28 -9622.13250 30.00000 1.4745570 L23
29 -688.51627 2.20000 1
30 993.96441 41.95512 1.4745570 L24
31 -641.46139 5.00000 1
32 ∞ 50.00000 1.4745570 L25
33 ∞ 72.78173 1

(Aspheric data)
Two sides: κ = 0
C ₄ = 5.443755 × 10 ⁻⁸ C ₆ = −6.995046 × 10 ⁻¹³
C ₈ = 1.02416 × 10 ⁻¹⁶ C ₁₀ = −4.50830 × 10 ⁻²⁰
C ₁₂ = 8.19138 × 10 ⁻²⁴ C ₁₄ = −5.55855 × 10 ⁻²⁸

9 planes (same plane as 18th and 20th planes): κ = 0
C ₄ = −1.78231 × 10 ⁻⁹ C ₆ = 6.332794 × 10 ⁻¹⁴
C ₈ = 2.69771 × 10 ⁻¹⁸ C ₁₀ = −4.84042 × 10 ⁻²²
C ₁₂ = 5.77071 × 10 ⁻²⁶ C ₁₄ = −2.667029 × 10 ⁻³⁰

(Values for conditional expressions)
d _m = 204.6 mm
f = 222.6 mm
f1 = −1083.4 mm
f2 = 193.3mm
(2) d _m /f=0.92
(3) (| f1 | / f2) / (f / (f−f2)) = 0.74

  FIG. 6 is a diagram showing spherical aberration, curvature of field, distortion, and coma in the projection optical system of the first example. In the aberration diagrams, NA represents the image-side numerical aperture of the projection optical system, and Y represents the image height (mm). Referring to each aberration diagram of FIG. 6, it can be seen that in the first example, various aberrations are satisfactorily corrected in the trapezoidal exposure region EF.

[Second Embodiment]
FIG. 7 is a diagram showing a lens configuration of the projection optical system according to the second example of the present embodiment. In the projection optical system PL of the second example, the first lens group G1 includes a negative lens L11 and three positive lenses L12, L13, and L14 in the order of incidence of light from the trapezoidal illumination area IF of the mask MA. It is configured. The third lens group G3 includes a negative lens L3. The second lens group G2 includes four positive lenses L21, L22, L23, and L24 and a plane parallel plate L25 in the order of incidence of light from the third lens group G3.

  In the second embodiment, similarly to the first embodiment, the curved reflecting surface CMa is configured as the reflecting surface of the concave reflecting mirror CM. However, unlike the first embodiment, the planar reflecting surface FMa is the light from the illumination area IF to the third lens group G3 in the optical surface on the plate PT side of the plano-convex lens L14 in the first lens group G1. It is formed in the region where does not pass. That is, the planar reflecting surface FMa is formed in a required region of the optical surface at the end on the plate PT side in the first lens group G1. In the first lens group G1, the negative lens L11 forms a negative lens group G1n, and the three positive lenses L12, L13, and L14 form a positive lens group G1p. Further, in the third lens group G3, the negative lens L3 constitutes a negative lens disposed in the vicinity of the curved reflecting surface CMa, and the curved reflecting surface CMa of the concave reflecting mirror CM functions as an aperture stop.

  In the second embodiment, the light from the trapezoidal illumination area IF of the mask MA is reflected by the curved reflecting surface CMa of the concave reflecting mirror CM sequentially through the first lens group G1 and the third lens group G3. The light is reflected by the planar reflecting surface FMa formed on the plano-convex lens L14 via the third lens group G3. The light reflected by the planar reflecting surface FMa sequentially passes through the third lens group G3 and the second lens group G2, and then forms an enlarged image of the pattern in the illumination area IF on the trapezoidal exposure area EF of the plate PT. Form. The following table (2) lists the values of the specifications of the projection optical system PL according to the second example.

Table (2)
(Main specifications)
λ = 365nm
NA = 0.054
β = 2.5

Surface number rd n Optical member object surface ∞ 28.55310 1
1 2952.94660 35.00000 1.4745570 L11
2 * 234.99689 2.40801 1
3 219.25957 35.00000 1.4876040 L12
4 -240.21150 2.00000 1
5 -444.98475 33.81802 1.4876040 L13
6 -207.80207 2.00000 1
7 291.56632 34.29093 1.4745570 L14
8 ∞ 70.35205 1
9 498.57177 45.00000 1.4745570 L3
10 * 397.41608 41.64697 1
11 ∞ 0.00000 1 (Aperture stop)
12 -425.46669 -41.64697 -1 CM
13 * 397.41608 -45.00000 -1.4745570 L3
14 498.57177 -70.35205 -1
15 ∞ 70.35205 1 FMa
16 498.57177 45.00000 1.4745570 L3
17 * 397.41608 79.40151 1
18 -915.85255 45.00000 1.4745570 L21
19 -472.12562 2.00000 1
20 -1256.52110 45.00000 1.4745570 L22
21 -567.94821 11.79928 1
22 -1925.68268 45.00000 1.4745570 L23
23 -607.60706 51.85740 1
24 -2364.28354 40.51970 1.4745570 L24
25 -406.90669 5.00000 1
26 ∞ 60.00000 1.4745570 L25
27 ∞ 65.99999 1

(Aspheric data)
Two sides: κ = 0
C ₄ = 2.53103 × 10 ⁻⁸ C ₆ = −9.229832 × 10 ⁻¹³
C ₈ = 3.993568 × 10 ⁻¹⁷ C ₁₀ = −2.237727 × 10 ⁻²¹
C ₁₂ = 7.80917 × 10 ⁻²⁵ C ₁₄ = −8.68391 × 10 ⁻²⁹

10 planes (same plane as 13th and 17th planes): κ = 0
C ₄ = 6.23109 × 10 ⁻⁹ C ₆ = −1.56696 × 10 ⁻¹³
C ₈ = 1.07571 × 10 ⁻¹⁸ C ₁₀ = 2.32955 × 10 ⁻²²
C ₁₂ = −2.664711 × 10 ⁻²⁶ C ₁₄ = 9.334409 × 10 ⁻³¹

(Values for conditional expressions)
d _m = 157.0 mm
f = 196.1 mm
f1 = −540.2 mm
f2 = 152.6 mm
(2) d _m /f=0.80
(3) (| f1 | / f2) / (f / (f−f2)) = 0.79

  FIG. 8 is a diagram showing spherical aberration, curvature of field, distortion, and coma in the projection optical system of the second example. In the aberration diagrams, NA represents the image-side numerical aperture of the projection optical system, and Y represents the image height (mm). Referring to the respective aberration diagrams of FIG. 8, it can be seen that also in the second example, various aberrations are satisfactorily corrected in the trapezoidal exposure area EF, as in the first example.

  The exposure apparatus of the above-described embodiment is manufactured by assembling various subsystems including the respective constituent elements recited in the claims of the present application so as to maintain predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Is done. In order to ensure these various accuracies, before and after assembly, various optical systems are adjusted to achieve optical accuracy, various mechanical systems are adjusted to achieve mechanical accuracy, and various electrical systems are Adjustments are made to achieve electrical accuracy. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection, electrical circuit wiring connection, pneumatic circuit piping connection and the like between the various subsystems. Needless to say, there is an assembly process for each subsystem before the assembly process from the various subsystems to the exposure apparatus. When the assembly process of the various subsystems to the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies as the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Next, a device manufacturing method using the exposure apparatus according to the above-described embodiment will be described. FIG. 9 is a flowchart showing a semiconductor device manufacturing process. As shown in FIG. 9, in the semiconductor device manufacturing process, a metal film is vapor-deposited on a wafer to be a semiconductor device substrate (step S40), and a photoresist, which is a photosensitive material, is applied on the vapor-deposited metal film ( Step S42). Subsequently, using the exposure apparatus of the above-described embodiment, the pattern formed on the reticle (mask) is transferred to each shot area (exposure area) on the wafer (step S44: exposure process), and this transfer is completed. Development, that is, development of the photoresist to which the pattern has been transferred (step S46: development process). Thereafter, the resist pattern generated on the surface of the wafer in step S46 is used as a mask for wafer processing, and processing such as etching is performed on the surface of the wafer (step S48: processing step).

  Here, the resist pattern is a photoresist layer (transfer pattern layer) in which unevenness having a shape corresponding to the pattern transferred by the exposure apparatus of the above-described embodiment is generated, and the recess penetrates the photoresist layer. It is what you are doing. In step S48, the surface of the wafer is processed through this resist pattern. The processing performed in step S48 includes, for example, at least one of etching of the wafer surface or film formation of a metal film or the like. In step S44, the exposure apparatus according to the above-described embodiment performs pattern transfer using the photoresist-coated wafer as a photosensitive substrate.

  FIG. 10 is a flowchart showing a manufacturing process of a liquid crystal device such as a liquid crystal display element. As shown in FIG. 10, in the manufacturing process of the liquid crystal device, a pattern formation process (step S50), a color filter formation process (step S52), a cell assembly process (step S54), and a module assembly process (step S56) are sequentially performed. In the pattern forming step of step S50, predetermined patterns such as a circuit pattern and an electrode pattern are formed on the glass substrate coated with a photoresist as the photosensitive substrate, using the projection exposure apparatus of the above-described embodiment. The pattern forming process includes an exposure process in which a pattern is transferred to a photoresist layer using the exposure apparatus of the above-described embodiment, and development of a photosensitive substrate to which the pattern is transferred, that is, development of a photoresist layer on a glass substrate. And a development step for generating a photoresist layer (transfer pattern layer) having a shape corresponding to the pattern, and a processing step for processing the surface of the glass substrate through the developed photoresist layer.

  In the color filter forming process in step S52, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning direction. In the cell assembly process in step S54, a liquid crystal panel (liquid crystal cell) is assembled using the glass substrate on which the predetermined pattern is formed in step S50 and the color filter formed in step S52. Specifically, for example, a liquid crystal panel is formed by injecting liquid crystal between a glass substrate and a color filter. In the module assembling process in step S56, various components such as an electric circuit and a backlight for performing the display operation of the liquid crystal panel are attached to the liquid crystal panel assembled in step S54.

  The present invention is not limited to application to an exposure apparatus for manufacturing a semiconductor device or a liquid crystal device. For example, an exposure apparatus for a display device such as a plasma display, an image sensor (CCD or the like), a micromachine, The present invention can be widely applied to an exposure apparatus for manufacturing various devices such as a thin film magnetic head and a DNA chip. Furthermore, the present invention can also be applied to an exposure process (exposure apparatus) when manufacturing a mask (photomask, reticle, etc.) on which mask patterns of various devices are formed using a photolithography process.

  In the above-described embodiment, an example is shown in which the present invention is applied to a projection optical system that is mounted on a multi-scanning exposure apparatus and forms an enlarged image of a mask pattern. However, the present invention is not limited to this, and in general, a catadioptric projection optical system that forms an image (enlarged image, reduced image, or equal-magnification image) of the first region of the first surface in the second region of the second surface Similarly, the present invention can be applied. Similarly, the present invention is also applied to an exposure apparatus that performs scanning exposure or batch exposure of a pattern arranged on the first surface to a substrate arranged on the second surface via one projection optical system. Can do.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows typically the basic composition of the projection optical system concerning this embodiment. It is a figure which shows the trapezoid exposure area | region in the surface of a plate. It is a figure which shows the positional relationship of each projection optical system, an exposure area | region, and an illumination area | region. It is a figure which shows the lens structure of the projection optical system concerning 1st Example. It is a figure which shows the spherical aberration in the projection optical system of 1st Example, a field curvature, a distortion aberration, and a coma aberration. It is a figure which shows the lens structure of the projection optical system concerning 2nd Example. It is a figure which shows the spherical aberration in the projection optical system of 2nd Example, a curvature of field, a distortion aberration, and a coma aberration. It is a flowchart which shows the manufacturing process of a semiconductor device. It is a flowchart which shows the manufacturing process of a liquid crystal device.

Explanation of symbols

MA mask IF illumination area PT plate EF exposure area PL projection optical system G1 first lens group G2 second lens group G3 third lens group CMa Curved reflecting surface FMa Planar reflecting surface

Claims (19)

In a catadioptric projection optical system that forms an image of a first region of a first surface in a second region of a second surface,
A first lens group having a positive refractive power;
A curved reflecting surface that reflects light from the first region via the first lens group toward the first surface;
A planar reflecting surface that reflects the light reflected by the curved reflecting surface toward the second surface;
A second lens group having a positive refractive power and condensing the light reflected by the planar reflecting surface on the second region;
The first lens group, the second lens group, and the curved reflecting surface are arranged coaxially along one linear optical axis,
The projection optical system, wherein the planar reflecting surface is arranged eccentrically with respect to the one optical axis. The projection optical system according to claim 1, wherein the curved reflecting surface is a concave reflecting surface on the first surface side. The projection optical system according to claim 1, wherein an enlarged image of the first region is formed in the second region. 4. The projection optical system according to claim 1, wherein the planar reflecting surface is disposed perpendicular to the one optical axis. 5. When the focal length of the first lens group is f, the said one of the distance along the optical axis between the curved reflecting surface and the planar reflection surface and d _m,
0.7 <d _m / f <1
The projection optical system according to claim 1, wherein the following condition is satisfied. When the focal length of the first lens group is f, the said one of the distance along the optical axis between the curved reflecting surface and the planar reflection surface and d _m,
0.9 <d _m / f <1
The projection optical system according to claim 1, wherein the following condition is satisfied. The projection optical system according to claim 1, wherein the first lens group includes a negative lens group and a positive lens group in the order of incidence of light from the first region. system. When the focal length of the first lens group is f, the focal length of the negative lens group is f1, and the focal length of the positive lens group is f2,
0.5 <(| f1 | / f2) / (f / (f−f2)) <1
The projection optical system according to claim 7, wherein the following condition is satisfied. Between the curved reflecting surface and the planar reflecting surface, it is arranged coaxially with the curved reflecting surface along the one optical axis, and at the end on the curved reflecting surface side. The projection optical system according to claim 1, further comprising a third lens group having a negative lens. The projection optical system according to claim 9, wherein the negative lens is disposed in the vicinity of the curved reflecting surface. Light from the first region enters the curved reflecting surface through the negative lens, and light reflected by the curved reflecting surface enters the planar reflecting surface through the negative lens. 11. The projection optical system according to claim 9, wherein the light reflected by the planar reflecting surface is incident on the second lens group through the negative lens. The projection optical system according to claim 1, wherein the planar reflecting surface is a reflecting surface of a plane reflecting mirror. The projection optical system according to claim 1, wherein the planar reflecting surface is formed on one optical surface of the first lens group. The projection optical system according to claim 13, wherein the planar reflecting surface is formed on an optical surface at an end portion on the second surface side in the first lens group. The projection optical system according to claim 1, wherein the first region and the second region are spaced apart from the one optical axis. In an exposure apparatus that transfers an image of a mask pattern placed on a mask stage to a photosensitive substrate placed on a substrate stage,
A projection optical system according to any one of claims 1 to 15, comprising:
The mask stage arranges the pattern on the first surface,
The exposure apparatus characterized in that the substrate stage arranges the photosensitive substrate on the second surface. The projection optical system transfers an image of the mask pattern moved in the predetermined direction along the first surface by the mask stage to the photosensitive substrate moved along the second surface by the substrate stage. The exposure apparatus according to claim 16, wherein the exposure apparatus is formed. The exposure apparatus according to claim 16 or 17, wherein a plurality of the projection optical systems are arranged along a direction intersecting with the predetermined direction. An exposure step of transferring the pattern to the photosensitive substrate using the exposure apparatus according to any one of claims 16 to 18,
Developing the photosensitive substrate to which the pattern has been transferred, and forming a transfer pattern layer having a shape corresponding to the pattern on the photosensitive substrate;
And a processing step of processing the photosensitive substrate through the transfer pattern layer.

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