JP2007059556A - Projection optical system, exposure system, and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an outside-axis visual-range reflection/refraction projection optical system, with a change in the shape of a refraction optical element due to radiation heat and aberrational fluctuations due to the change in the refraction factor suppressed to be at a low level. <P>SOLUTION: The outside-axis visual-range reflection/refraction projection optical system includes at least one concave reflecting mirror and a plurality of refractive optical elements. In the projection optical system, a heat conductive member (81) is disposed near at least one specified refractive optical element (80), the heat conductive member (81) made of a material, having thermal conductivity higher than that of a material making the specified refractive optical element (80). The heat conductive member (81) is so arranged that a distance from the thermal conductive member (81) to the closer side of a light exposure region (80a) for the specified refractive optical element (80) is smaller than the distance from the heat conductive member (81) to the farther side of the light exposure region (80a), with regard to a direction (Y direction), corresponding to one axial direction at the position of the specified refractive optical element (80). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a projection optical system, an exposure apparatus, and an exposure method, and more particularly to a projection optical system suitable for an exposure apparatus used when manufacturing a microdevice such as a semiconductor element or a liquid crystal display element in a photolithography process. is there.

  In a photolithography process for manufacturing semiconductor elements, etc., a mask (or reticle) pattern image is projected and exposed on a photosensitive substrate (a wafer coated with a photoresist, a glass plate, etc.) via a projection optical system. An exposure apparatus is used. In the exposure apparatus, as the degree of integration of semiconductor elements and the like is improved, the resolving power (resolution) required for the projection optical system is increasing.

  Therefore, in order to satisfy the requirement for the resolution of the projection optical system, it is necessary to shorten the wavelength λ of the illumination light (exposure light) and increase the image-side numerical aperture NA of the projection optical system. Specifically, the resolution of the projection optical system is represented by k · λ / NA (k is a process coefficient). The image-side numerical aperture NA is n, where n is the refractive index of the medium (usually a gas such as air) between the projection optical system and the photosensitive substrate, and θ is the maximum incident angle on the photosensitive substrate.・ It is expressed by sinθ.

  In this case, if the maximum incident angle θ is increased to increase the image-side numerical aperture, the incident angle to the photosensitive substrate and the exit angle from the projection optical system increase, and the reflection loss on the optical surface increases. Thus, a large effective image-side numerical aperture cannot be ensured. Therefore, an immersion technique is known in which an image-side numerical aperture is increased by filling a medium such as a liquid having a high refractive index in the optical path between the projection optical system and the photosensitive substrate (for example, Patent Document 1). ).

International Publication No. WO2004 / 019128 Pamphlet

  In general, in a projection optical system having a large image-side numerical aperture, the use of a catadioptric optical system is desirable from the viewpoint of obtaining the flatness of the image by satisfying the Petzval condition even in a dry system without being limited to an immersion system. From the viewpoint of adaptability to all fine patterns, it is desirable to adopt an off-axis visual field optical system whose effective visual field does not include the optical axis. In addition to the immersion type projection optical system, it has been studied to adopt an off-axis visual field optical system as a VUV projection optical system using vacuum ultraviolet light (VUV light: Vacuum Ultraviolet ray) as exposure light.

  However, in an off-axis visual projection optical system in which the effective field does not include the optical axis, an irradiation area (effective imaging) is particularly obtained in a lens (generally a refractive optical element) close to an object or an image (including a secondary image). The deviation from the optical axis of the region where the light beam passes (light irradiation region) is relatively large. As a result, asymmetry occurs in the temperature change in these lenses that have been irradiated with light, and as a result, aberration fluctuations occur due to shape changes and refractive index changes. It is difficult to correct the aberration variation accompanying the change in shape and refractive index due to the irradiation heat by a lens control system that drives the lens up and down.

  The present invention has been made in view of the above-described problems. For example, in an off-axis visual field optical system, fluctuations in aberration caused by changes in the shape and refractive index of a refractive optical element due to irradiation heat are suppressed to a small level. It is an object to provide a catadioptric projection optical system. Further, the present invention is an optical system of an off-axis visual field type, for example, using a catadioptric projection optical system in which aberration variation due to a change in shape and refractive index of a refractive optical element due to irradiation heat is suppressed to a small level. An object of the present invention is to provide an exposure apparatus and an exposure method capable of projecting and exposing a precise pattern with high accuracy.

In order to solve the above problems, in the first aspect of the present invention, in the projection optical system for forming an image in the effective field of view of the first surface in the effective projection region on the second surface,
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
The projection optical system includes at least one specific refractive optical element and a heat conduction formed by a material having a higher thermal conductivity than a material that is disposed in the vicinity of the specific refractive optical element and forms the specific refractive optical element. With members,
The light irradiation area on the specific refractive optical element is decentered from the optical axis of the specific refractive optical element along a direction corresponding to the one axial direction at the position of the specific refractive optical element,
Dividing the specific refractive optical element into a first region and a second region opposite to the first refractive index optical element by a plane including the optical axis of the specific refractive optical element and the other of the two orthogonal axes. Is the first region, the amount of heat transferred from the first region of the specific refractive optical element to the heat conducting member is transferred from the second region of the specific refractive optical element to the heat conducting member. Provided is a projection optical system, further comprising heat transport means for making the amount of heat to be moved larger.

In the second aspect of the present invention, in the projection optical system that projects the image of the first surface onto the second surface,
The projection optical system includes at least one concave reflecting mirror and a plurality of refractive optical elements, and forms an image in an effective field on the first surface in an effective projection area on the second surface;
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
The effective projection area on the second surface is eccentric from the optical axis along an axial direction on the second surface corresponding to the one axial direction;
In the vicinity of at least one specific refractive optical element among the plurality of refractive optical elements, a heat conductive member formed of a material having a higher thermal conductivity than a material forming the specific refractive optical element is disposed,
The heat conducting member has a distance from a side closer to the light irradiation region of the specific refractive optical element with respect to a direction corresponding to the one axial direction at the position of the specific refractive optical element. The projection optical system is characterized in that the projection optical system is disposed so as to be smaller than the distance of the projection optical system.

In the third aspect of the present invention, in the projection optical system for forming the image of the first surface on the second surface,
Comprising at least one concave reflecting mirror and a plurality of refractive optical elements, forming an image in an effective field on the first surface in an effective projection area on the second surface;
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
In the vicinity of at least one specific refractive optical element among the plurality of refractive optical elements, a heat conductive member formed of a material having a higher thermal conductivity than a material forming the specific refractive optical element is disposed,
Dividing the specific refractive optical element into a first region and a second region opposite to the first refractive index optical element by a plane including the optical axis of the specific refractive optical element and the other of the two orthogonal axes. Is the first region, the area of the first partial region in the first region of the specific refractive optical element in which the distance from the heat conducting member is 200 μm or less is Sa, and the specific refraction In the second region of the optical element, the area of the second partial region in which the distance from the heat conducting member is 200 μm or less is Sb, the distance between the center of the effective field on the first surface and the optical axis is O, When the maximum image height on the second surface is Y,
0.75 <Sa (YO) / Sb (Y + O) <7.5
A projection optical system characterized by satisfying the above conditions is provided.

In the fourth aspect of the present invention, in the projection optical system for forming the image of the first surface on the second surface,
Comprising at least one concave reflecting mirror and a plurality of refractive optical elements, forming an image in an effective field on the first surface in an effective projection area on the second surface;
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
In the vicinity of at least one specific refractive optical element among the plurality of refractive optical elements, a heat conductive member formed of a material having a higher thermal conductivity than a material forming the specific refractive optical element is disposed,
Dividing the specific refractive optical element into a first region and a second region opposite to the first refractive index optical element by a plane including the optical axis of the specific refractive optical element and the other of the two orthogonal axes. When the first region is the wider region through which
A projection optical system is provided, wherein a substance having a higher thermal conductivity than a gas is disposed between the surface of the refractive optical element in the first region and the heat conducting member.

In the fifth aspect of the present invention, in the projection optical system that projects the image of the first surface onto the second surface,
A first optical unit having at least one refractive optical element disposed in an optical path between the first surface and the second surface;
A second optical unit disposed in an optical path between the first optical unit and the second surface and including at least one concave reflecting mirror;
A third optical unit having a plurality of refractive optical elements disposed in an optical path between the second optical unit and the second surface;
A first reflecting surface disposed on the first side surface of the triangular prism-shaped base material, disposed in the optical path between the first optical unit and the second optical unit;
A second reflecting surface that is disposed in the optical path between the second optical unit and the third optical unit, and is formed on a second side surface of the triangular prism-shaped substrate;
A projection optical device comprising: a heat conducting member disposed near or in contact with the third side surface of the base material and formed of a material having a higher thermal conductivity than the base material. Provide the system.

In the sixth aspect of the present invention, in the projection optical system that projects the image of the first surface onto the second surface,
A first optical unit having at least one refractive optical element disposed in an optical path between the first surface and the second surface;
A second optical unit disposed in an optical path between the first optical unit and the second surface and including at least one concave reflecting mirror;
A third optical unit having a plurality of refractive optical elements disposed in an optical path between the second optical unit and the second surface;
A first reflecting surface disposed on the first side surface of the triangular prism-shaped base material, disposed in the optical path between the first optical unit and the second optical unit;
A second reflecting surface that is disposed in the optical path between the second optical unit and the third optical unit, and is formed on a second side surface of the triangular prism-shaped base material;
A through hole or a non-through hole extending from one end face toward the other end face is formed in the triangular prism-shaped base material,
It further includes a heat conducting member that is disposed close to or in contact with the inner side surface of the through hole or the inner side surface of the non-through hole and is formed of a material having a higher thermal conductivity than the base material. A projection optical system is provided.

  In a seventh aspect of the present invention, a first image for projecting an image of the pattern onto a photosensitive substrate set on the second surface based on illumination light from a predetermined pattern set on the first surface. An exposure apparatus comprising the projection optical system according to any one of the first to sixth embodiments is provided.

In an eighth aspect of the present invention, a setting step for setting a predetermined pattern on the first surface;
An exposure step of projecting and exposing an image of the pattern onto the photosensitive substrate set on the second surface via the projection optical systems of the first to sixth modes based on illumination light from the predetermined pattern; The exposure method characterized by including these is provided.

  In the present invention, for example, in an off-axis field-type catadioptric projection optical system, the light irradiation region is formed of a material having high thermal conductivity in the vicinity of a specific refractive optical element having a relatively large deviation from the optical axis. The heat conducting member is arranged so that the distance from the side closer to the light irradiation region along the eccentric direction from the optical axis of the light irradiation region is smaller than the distance from the side far from the light irradiation region. As a result, the thermal conduction action of the heat conducting member alleviates the asymmetry of the temperature change in the refractive optical element due to the eccentricity from the optical axis of the light irradiation region, and consequently the shape change and refraction of the refractive optical element due to the irradiation heat. The rate change is kept small.

  Thus, according to the present invention, it is possible to realize a catadioptric projection optical system that is an off-axis visual field optical system, for example, in which aberration fluctuations caused by changes in the shape and refractive index of the refractive optical element due to heat of irradiation are kept small. it can. Further, in the exposure apparatus and exposure method of the present invention, for example, an off-axis visual field optical system, which is a catadioptric projection optical in which aberration fluctuations caused by changes in the shape and refractive index of the refractive optical element due to irradiation heat are suppressed to a small level. By using the system, a fine pattern can be projected and exposed with high accuracy with high accuracy, and a good microdevice can be manufactured with high accuracy.

  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 FIG. 1, the X axis and the Y axis are set in a direction parallel to the wafer W, and the Z axis is set in a direction orthogonal to the wafer W. More specifically, the XY plane is set parallel to the horizontal plane, and the + Z axis is set upward along the vertical direction.

  As shown in FIG. 1, the exposure apparatus of this embodiment includes, for example, an ArF excimer laser light source that is an exposure light source, and includes an illumination optical system 1 that includes an optical integrator (homogenizer), a field stop, a condenser lens, and the like. ing. Exposure light (exposure beam) IL composed of ultraviolet pulsed light having a wavelength of 193 nm emitted from the light source passes through the illumination optical system 1 and illuminates the reticle (mask) R. A pattern to be transferred is formed on the reticle R, and a rectangular (slit-like) pattern region having a long side along the X direction and a short side along the Y direction is illuminated in the entire pattern region. Is done.

  The light that has passed through the reticle R forms a reticle pattern at a predetermined reduction projection magnification in an exposure area on a wafer (photosensitive substrate) W coated with a photoresist via an immersion type projection optical system PL. That is, a rectangular shape having a long side along the X direction and a short side along the Y direction on the wafer W so as to optically correspond to a rectangular illumination region (effective field of view) on the reticle R. A pattern image is formed in the static exposure area (effective projection area: effective exposure area) of the shape.

  FIG. 2 is a diagram showing a positional relationship between a rectangular still exposure region (that is, an effective exposure region) formed on the wafer in this embodiment and a reference optical axis. In the present embodiment, as shown in FIG. 2, within a circular area (image circle) IF having a radius B centered on the reference optical axis AX, the reference optical axis AX is separated from the reference optical axis AX by an off-axis amount A. A rectangular effective exposure region ER having a desired size is set at a predetermined position. Here, the length in the X direction of the effective exposure region ER is LX, and the length in the Y direction is LY.

  Therefore, although not shown, on the reticle R, the effective exposure region ER is located at a position that is away from the reference optical axis AX in the Y direction by a distance corresponding to the off-axis amount A, corresponding to the rectangular effective exposure region ER. A rectangular illumination area (that is, an effective illumination area) having a size and shape corresponding to is formed. In other words, the effective projection area (effective exposure area ER) on the wafer W is decentered from the reference optical axis AX along the Y direction, and the effective field of view (effective illumination area) on the reticle R is corresponding to this. Is also decentered from the reference optical axis AX along the Y direction.

  The reticle R is held parallel to the XY plane on the reticle stage RST, and a mechanism for finely moving the reticle R in the X direction, the Y direction, and the rotation direction is incorporated in the reticle stage RST. In reticle stage RST, positions in the X direction, Y direction, and rotational direction are measured and controlled in real time by a reticle laser interferometer (not shown). The wafer W is fixed parallel to the XY plane on the Z stage 9 via a wafer holder (not shown).

  The Z stage 9 is fixed on an XY stage 10 that moves along an XY plane substantially parallel to the image plane of the projection optical system PL, and the focus position (position in the Z direction) and tilt of the wafer W are fixed. Control the corners. The Z stage 9 is measured and controlled in real time by the wafer laser interferometer 13 using the moving mirror 12 provided on the Z stage 9 in the X direction, the Y direction, and the rotational direction.

  The XY stage 10 is placed on the base 11 and controls the X direction, Y direction, and rotation direction of the wafer W. On the other hand, the main control system 14 provided in the exposure apparatus of the present embodiment adjusts the position of the reticle R in the X direction, the Y direction, and the rotational direction based on the measurement values measured by the reticle laser interferometer. That is, the main control system 14 adjusts the position of the reticle R by transmitting a control signal to a mechanism incorporated in the reticle stage RST and finely moving the reticle stage RST.

  The main control system 14 adjusts the focus position (position in the Z direction) and the tilt angle of the wafer W in order to adjust the surface on the wafer W to the image plane of the projection optical system PL by the auto focus method and the auto leveling method. I do. That is, the main control system 14 transmits a control signal to the wafer stage drive system 15 and drives the Z stage 9 by the wafer stage drive system 15 to adjust the focus position and tilt angle of the wafer W.

  Further, the main control system 14 adjusts the position of the wafer W in the X direction, the Y direction, and the rotation direction based on the measurement values measured by the wafer laser interferometer 13. That is, the main control system 14 transmits a control signal to the wafer stage drive system 15 and drives the XY stage 10 by the wafer stage drive system 15 to adjust the position of the wafer W in the X direction, the Y direction, and the rotation direction. .

  At the time of exposure, the main control system 14 transmits a control signal to a mechanism incorporated in the reticle stage RST and also transmits a control signal to the wafer stage drive system 15, and a speed ratio corresponding to the projection magnification of the projection optical system PL. Then, the reticle stage RST and the XY stage 10 are driven to project and expose the pattern image of the reticle R into a predetermined shot area on the wafer W. Thereafter, the main control system 14 transmits a control signal to the wafer stage drive system 15, and drives the XY stage 10 by the wafer stage drive system 15, thereby step-moving another shot area on the wafer W to the exposure position.

  In this way, the operation of scanning and exposing the pattern image of the reticle R on the wafer W by the step-and-scan method is repeated. That is, in the present embodiment, the position of the reticle R and the wafer W is controlled using the wafer stage drive system 15 and the wafer laser interferometer 13, and the short side direction of the rectangular stationary exposure region and the stationary illumination region, that is, the Y direction. The wafer stage W has a width equal to the long side LX of the stationary exposure region by moving (scanning) the reticle stage RST and the XY stage 10 along with the reticle R and the wafer W synchronously. In addition, the reticle pattern is scanned and exposed to an area having a length corresponding to the scanning amount (movement amount) of the wafer W.

  FIG. 3 is a diagram schematically illustrating a configuration between the boundary lens and the wafer in each example of the present embodiment. Referring to FIG. 3, in the projection optical system PL according to each example of the present embodiment, the reticle R side (object side) surface is in contact with the second liquid Lm2, and the wafer W side (image side) surface is the first. An in-liquid parallel flat plate Lp that is in contact with the liquid Lm1 is disposed closest to the wafer. A boundary lens Lb is disposed adjacent to the in-liquid parallel flat plate Lp so that the reticle R side surface is in contact with the gas and the wafer W side surface is in contact with the second liquid Lm2.

  In each example of the present embodiment, for example, pure water (deionized water) that can be easily obtained in large quantities at a semiconductor manufacturing factory or the like as the first liquid Lm1 and the second liquid Lm2 having a refractive index greater than 1.1. Used. The boundary lens Lb is a positive lens having a convex surface on the reticle R side and a flat surface on the wafer W side. Further, the boundary lens Lb and the liquid parallel plane plate Lp are both made of quartz. This is because it is difficult to stably maintain the imaging performance of the projection optical system because the fluorite is soluble in water when the boundary lens Lb and the liquid parallel plane plate Lp are formed of fluorite. Because it becomes.

  In addition, it is known that the internal refractive index distribution of fluorite has a high-frequency component, and variations in the refractive index including this high-frequency component may cause flare, which degrades the imaging performance of the projection optical system. Easy to do. Furthermore, fluorite is known to have intrinsic birefringence, and in order to maintain good imaging performance of the projection optical system, it is necessary to correct the influence of this intrinsic birefringence. Therefore, from the viewpoint of the solubility of fluorite, the high frequency component of the refractive index distribution, and the intrinsic birefringence, it is preferable to form the boundary lens Lb and the liquid parallel plane plate Lp from quartz.

  In the step-and-scan type exposure apparatus that performs scanning exposure while moving the wafer W relative to the projection optical system PL, the boundary lens Lb of the projection optical system PL and the wafer W In order to continue filling the liquid (Lm1, Lm2) in the optical path between, for example, the technique disclosed in International Publication No. WO99 / 49504, the technique disclosed in Japanese Patent Laid-Open No. 10-303114, or the like is used. Can do.

  In the technique disclosed in International Publication No. WO99 / 49504, the liquid adjusted to a predetermined temperature from the liquid supply device via the supply pipe and the discharge nozzle is filled with the optical path between the boundary lens Lb and the wafer W. The liquid is recovered from the wafer W via the recovery pipe and the inflow nozzle by the liquid supply device. On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 10-303114, the wafer holder table is configured in a container shape so that the liquid can be accommodated, and the wafer W is evacuated at the center of the inner bottom (in the liquid). It is positioned and held by suction. Further, the lens barrel tip of the projection optical system PL reaches the liquid, and the optical surface on the wafer side of the boundary lens Lb reaches the liquid.

  In the present embodiment, as shown in FIG. 1, pure water as the first liquid Lm1 is circulated in the optical path between the liquid parallel flat plate Lp and the wafer W using the first water supply / drainage mechanism 21. . In addition, the second water supply / drainage mechanism 22 is used to circulate pure water as the second liquid Lm2 in the optical path between the boundary lens Lb and the in-liquid parallel flat plate Lp. In this way, by circulating pure water as the immersion liquid at a minute flow rate, it is possible to prevent deterioration of the liquid due to antiseptic, fungicidal and other effects.

In each example of the present embodiment, the aspherical surface is along the optical axis from the tangential plane at the apex of the aspherical surface to the position on the aspherical surface at the height y, where y is the height in the direction perpendicular to the optical axis. When the distance (sag amount) is z, the apex radius of curvature is r, the cone coefficient is κ, and the n-th aspherical coefficient is C _n , the following equation (a) is expressed. 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)

  In each example of the present embodiment, the projection optical system PL is a first imaging optical system (first optical system) for forming a first intermediate image of the pattern of the reticle R disposed on the object surface (first surface). 1 optical unit) G1 and a second image formation for forming a second intermediate image of the reticle pattern (an image of the first intermediate image and a secondary image of the reticle pattern) based on the light from the first intermediate image Based on light from the optical system (second optical unit) G2 and the second intermediate image, a final image of the reticle pattern (a reduced image of the reticle pattern) is formed on the wafer W arranged on the image surface (second surface). And a third imaging optical system (third optical unit) G3. Here, both the first imaging optical system G1 and the third imaging optical system G3 are refractive optical systems, and the second imaging optical system G2 is a catadioptric optical system including a concave reflecting mirror CM.

  A first planar reflecting mirror (first deflecting mirror) M1 is disposed in the optical path between the first imaging optical system G1 and the second imaging optical system G2, and the second imaging optical system G2 and the second imaging optical system G2 A second planar reflecting mirror (second deflecting mirror) M2 is disposed in the optical path between the three imaging optical systems G3. Thus, in the projection optical system PL of each embodiment, the light from the reticle R forms a first intermediate image of the reticle pattern in the vicinity of the first planar reflecting mirror M1 via the first imaging optical system G1. Next, the light from the first intermediate image forms a second intermediate image of the reticle pattern in the vicinity of the second planar reflecting mirror M2 via the second imaging optical system G2. Further, the light from the second intermediate image forms a final image of the reticle pattern on the wafer W via the third imaging optical system G3.

  In the projection optical system PL of each embodiment, the first imaging optical system G1 and the third imaging optical system G3 have an optical axis AX1 and an optical axis AX3 extending linearly along the vertical direction, and the optical axis AX1 and the optical axis AX3 coincide with the reference optical axis AX. On the other hand, the second imaging optical system G2 has an optical axis AX2 that extends linearly along the horizontal direction (perpendicular to the reference optical axis AX). Thus, the reticle R, the wafer W, all the optical members constituting the first imaging optical system G1 and all the optical members constituting the third imaging optical system G3 are along a plane perpendicular to the direction of gravity, that is, a horizontal plane. They are arranged parallel to each other. Further, the first planar reflecting mirror M1 and the second planar reflecting mirror M2 each have a reflecting surface set so as to form an angle of 45 degrees with respect to the reticle surface. The reflecting mirror M2 is integrally configured as one optical member. In each embodiment, the projection optical system PL is substantially telecentric on both the object side and the image side.

[First embodiment]
FIG. 4 is a diagram showing a lens configuration of the projection optical system according to the first example of the present embodiment. Referring to FIG. 4, in the projection optical system PL according to the first example, the first imaging optical system G1 includes, in order from the reticle side, a plane parallel plate P1, a biconvex lens L11, and a positive surface with a convex surface facing the reticle side. A meniscus lens L12, a biconvex lens L13, a biconcave lens L14 having an aspheric concave surface facing the reticle side, a positive meniscus lens L15 having a convex surface facing the reticle side, and a positive meniscus lens L16 having a concave surface facing the reticle side A negative meniscus lens L17 having a concave surface facing the reticle, a positive meniscus lens L18 having an aspheric concave surface facing the reticle, a positive meniscus lens L19 having a concave surface facing the reticle, a biconvex lens L110, A positive meniscus lens L111 having an aspherical concave surface facing the wafer side.

  The second imaging optical system G2 includes a negative meniscus lens L21 having a concave surface on the reticle side and a negative meniscus having a concave surface on the reticle side in order from the reticle side (that is, the incident side) along the light traveling path. The lens L22 includes a concave reflecting mirror CM having a concave surface facing the reticle. Further, the third imaging optical system G3 includes, in order from the reticle side (that is, the incident side), a positive meniscus lens L31 having a concave surface facing the reticle side, a biconvex lens L32, and a positive meniscus lens L33 having a convex surface facing the reticle side. A positive meniscus lens L34 having an aspherical concave surface facing the wafer, a biconcave lens L35, a biconcave lens L36 having an aspherical concave surface facing the wafer, and an aspherical concave surface facing the reticle. A positive meniscus lens L37, a positive meniscus lens L38 having an aspheric concave surface facing the wafer, a negative meniscus lens L39 having an aspheric concave surface facing the wafer, and an aspheric concave surface on the reticle side. A positive meniscus lens L310, a biconvex lens L311, an aperture stop AS, a planoconvex lens L312 with a plane facing the wafer side, a wafer A positive meniscus lens L313 with an aspherical concave surface facing the side, a positive meniscus lens L314 with an aspherical concave surface facing the wafer, a planoconvex lens L315 (boundary lens Lb) with a flat surface facing the wafer, It is comprised by the parallel plane board Lp.

In the first embodiment, ArF excimer laser light (center wavelength λ) is used light (exposure light) on the optical path between the boundary lens Lb and the plane parallel plate Lp and on the optical path between the plane parallel plate Lp and the wafer W. = 193.306 nm) is filled with pure water (Lm1, Lm2) having a refractive index of 1.435876. Further, all the light transmitting members including the boundary lens Lb and the plane parallel plate Lp are formed of quartz (SiO ₂ ) having a refractive index of 1.5603261 with respect to the center wavelength of the used light.

  In the following table (1), values of specifications of the projection optical system PL according to the first example are listed. In Table (1), λ is the center wavelength of the exposure light, β is the projection magnification (imaging magnification of the entire system), NA is the image side (wafer side) numerical aperture, and B is on the wafer W. , A is the off-axis amount of the effective exposure area ER, LX is the dimension along the X direction of the effective exposure area ER (long side dimension), and LY is the Y direction of the effective exposure area ER. The dimensions along the lines (dimensions on the short side) are respectively shown.

  The surface number is the order of the surface from the reticle side along the path of the light beam from the reticle surface that is the object surface (first surface) to the wafer surface that is the image surface (second surface). The radius of curvature of the surface (vertex radius of curvature: mm in the case of an aspherical surface), d represents the on-axis interval of each surface, that is, the surface interval (mm), and n represents the refractive index with respect to the center wavelength. Note that the surface distance d changes its sign each time it is reflected. Therefore, the sign of the surface interval d is negative in the optical path from the reflecting surface of the first flat reflecting mirror M1 to the concave reflecting mirror CM and in the optical path from the second flat reflecting mirror M2 to the image plane, and in the other optical paths. It is positive.

  In the first imaging optical system G1, the radius of curvature of the convex surface toward the reticle side is positive, and the radius of curvature of the concave surface toward the reticle side is negative. In the second imaging optical system G2, the radius of curvature of the concave surface is made positive toward the incident side (reticle side) along the light traveling path, and the radius of curvature of the convex surface is made negative toward the incident side. In the third imaging optical system G3, the radius of curvature of the concave surface toward the reticle side is positive, and the radius of curvature of the convex surface toward the reticle side is negative. The notation in Table (1) is the same in the following Table (2).

Table (1)
(Main specifications)
λ = 193.306 nm
β = 1/4
NA = 1.32
B = 15.3mm
A = 2.8mm
LX = 26mm
LY = 5mm

(Optical member specifications)
Surface number r dn optical member (reticle surface) 113.7542
1 ∞ 8.0000 1.5603261 (P1)
2 ∞ 6.0000
3 961.49971 52.0000 1.5603261 (L11)
4 -260.97642 1.0000
5 165.65618 35.7731 1.5603261 (L12)
6 329.41285 15.7479
7 144.73700 56.4880 1.5603261 (L13)
8 -651.17229 4.1450
9 * -678.61021 18.2979 1.5603261 (L14)
10 173.73534 1.0000
11 82.85141 28.4319 1.5603261 (L15)
12 122.17403 24.6508
13 -632.23083 15.8135 1.5603261 (L16)
14 -283.76586 22.9854
15 -95.83749 44.8780 1.5603261 (L17)
16 -480.25701 49.9532
17 * -327.24655 37.6724 1.5603261 (L18)
18 -152.74838 1.0000
19 -645.51205 47.0083 1.5603261 (L19)
20 -172.70890 1.0000
21 1482.42136 32.7478 1.5603261 (L110)
22 -361.68453 1.0000
23 185.06735 36.2895 1.5603261 (L111)
24 * 1499.92500 72.0000
25 ∞ -204.3065 (M1)
26 115.50235 -15.0000 1.5603261 (L21)
27 181.35110 -28.1819
28 107.57500 -18.0000 1.5603261 (L22)
29 327.79447 -34.9832
30 165.18700 34.9832 (CM)
31 327.79446 18.0000 1.5603261 (L22)
32 107.57500 28.1819
33 181.35110 15.0000 1.5603261 (L21)
34 115.50235 204.3065
35 ∞ -72.0000 (M2)
36 552.89298 -24.4934 1.5603261 (L31)
37 211.40931 -1.0000
38 -964.15750 -27.5799 1.5603261 (L32)
39 451.41200 -1.0000
40 -239.74429 -35.7714 1.5603261 (L33)
41 -171769.23040 -1.0000
42 -206.94777 -50.0000 1.5603261 (L34)
43 * -698.47035 -43.1987
44 560.33453 -10.0000 1.5603261 (L35)
45 -116.92245 -46.5360
46 209.32811 -10.0000 1.5603261 (L36)
47 * -189.99848 -23.6644
48 * 1878.63986 -31.5066 1.5603261 (L37)
49 211.85278 -1.0000
50 -322.20466 -33.1856 1.5603261 (L38)
51 * -1160.22740 -10.0172
52 -2715.10365 -22.0000 1.5603261 (L39)
53 * -959.87714 -42.0799
54 * 727.37853 -62.0255 1.5603261 (L310)
55 240.59248 -1.0000
56 -16276.86134 -62.1328 1.5603261 (L311)
57 333.64919 -1.0000
58 ∞ -1.0000 (AS)
59 -303.09919 -68.2244 1.5603261 (L312)
60 ∞ -1.0000
61 -182.25869 -77.6122 1.5603261 (L313)
62 * -472.72383 -1.0000
63 -131.14200 -49.9999 1.5603261 (L314)
64 * -414.78286 -1.0000
65 -75.90800 -43.3351 1.5603261 (L315: Lb)
66 ∞ -1.0000 1.435876 (Lm2)
67 ∞ -13.0000 1.5603261 (Lp)
68 ∞ -2.9999 1.435876 (Lm1)
(Wafer surface)

(Aspheric data)
9 faces κ = 0
C ₄ = −7.99031 × 10 ⁻⁸ C ₆ = 8.6709 × 10 ⁻¹²
C ₈ = −6.5472 × 10 ⁻¹⁶ C ₁₀ = 1.5504 × 10 ⁻²⁰
C ₁₂ = 2.6800 × 10 ⁻²⁴ C ₁₄ = −2.66032 × 10 ⁻²⁸
C ₁₆ = 7.3308 × 10 ⁻³³ C ₁₈ = 0

17 faces κ = 0
C ₄ = 4.7672 × 10 ⁻⁹ C ₆ = −8.7145 × 10 ⁻¹³
C ₈ = −2.88591 × 10 ⁻¹⁷ C ₁₀ = 3.99981 × 10 ⁻²¹
C ₁₂ = −1.9927 × 10 ⁻²⁵ C ₁₄ = 2.8410 × 10 ⁻³⁰
C ₁₆ = 6.5538 × 10 ⁻³⁵ C ₁₈ = 0

24 surfaces κ = 0
C ₄ = 2.7118 × 10 ⁻⁸ C ₆ = −4.0362 × 10 ⁻¹³
C ₈ = 8.5346 × 10 ⁻¹⁸ C ₁₀ = −1.7653 × 10 ⁻²²
C ₁₂ = −1.856 × 10 ⁻²⁷ C ₁₄ = 5.2597 × 10 ⁻³¹
C ₁₆ = −2.0897 × 10 ⁻³⁵ C ₁₈ = 0

43 planes κ = 0
C ₄ = −1.88839 × 10 ⁻⁸ C ₆ = 5.609 × 10 ⁻¹³
C ₈ = −1.8306 × 10 ⁻¹⁷ C ₁₀ = 2.2177 × 10 ^{−21
_{C 12 = -2.3512 × 10 -25 C}} 14 = 1.7766 × 10 -29
C ₁₆ = −6.5390 × 10 ⁻³⁴ C ₁₈ = 0

47 faces κ = 0
C ₄ = 9.0773 × 10 ⁻⁸ C ₆ = −5.4651 × 10 ⁻¹²
C ₈ = 4.4000 × 10 ⁻¹⁶ C ₁₀ = −2.7426 × 10 ⁻²⁰
C ₁₂ = 3.2149 × 10 ⁻²⁵ C ₁₄ = 2.3641 × 10 ⁻²⁸
C ₁₆ = −1.33953 × 10 ⁻³² C ₁₈ = 0

48 faces κ = 0
C ₄ = 3.0443 × 10 ⁻⁸ C ₆ = −1.6528 × 10 ⁻¹²
C ₈ = 2.3949 × 10 ⁻¹⁷ C ₁₀ = −4.4953 × 10 ⁻²¹
C ₁₂ = 3.0165 × 10 ⁻²⁵ C ₁₄ = −1.2463 × 10 ⁻²⁸
C ₁₆ = 1.0783 × 10 ⁻³² C ₁₈ = 0

51 plane κ = 0
C ₄ = 1.8357 × 10 ⁻⁸ C ₆ = −4.3103 × 10 ⁻¹³
C ₈ = −9.4499 × 10 ⁻¹⁷ C ₁₀ = 4.3247 × 10 ⁻²¹
C ₁₂ = −1.6979 × 10 ⁻²⁵ C ₁₄ = 8.6892 × 10 ⁻³⁰
C ₁₆ = −1.5935 × 10 ⁻³⁴ C ₁₈ = 0

53 plane κ = 0
^{_{C 4 = -3.9000 × 10 -8 C}} 6 = -7.2737 × 10 -13
C ₈ = 1.1921 × 10 ⁻¹⁶ C ₁₀ = −2.6393 × 10 ⁻²¹
C ₁₂ = −3.1544 × 10 ⁻²⁶ C ₁₄ = 1.8774 × 10 ⁻³⁰
C ₁₆ = −2.3545 × 10 ⁻³⁵ C ₁₈ = 0

54 faces κ = 0
C ₄ = 1.9116 × 10 ⁻⁸ C ₆ = −6.77783 × 10 ⁻¹³
C ₈ = 1.5688 × 10 ⁻¹⁷ C ₁₀ = −6.0850 × 10 ⁻²²
C ₁₂ = 1.8575 × 10 ⁻²⁶ C ₁₄ = −4.2147 × 10 ⁻³¹
C ₁₆ = 7.3240 × 10 ⁻³⁶ C ₁₈ = 0

62 plane κ = 0
C ₄ = 3.0649 × 10 ⁻⁸ C ₆ = −2.3613 × 10 ⁻¹²
C ₈ = 1.5604 × 10 ⁻¹⁶ C ₁₀ = −7.3591 × 10 ⁻²¹
C ₁₂ = 2.1593 × 10 ⁻²⁵ C ₁₄ = −3.5918 × 10 ⁻³⁰
C ₁₆ = 2.5879 × 10 ⁻³⁵ C ₁₈ = 0

64 faces κ = 0
C ₄ = −6.0849 × 10 ⁻⁸ C ₆ = −8.7021 × 10 ⁻¹³
C ₈ = −1.5623 × 10 ⁻¹⁶ C ₁₀ = 1.5681 × 10 ⁻²⁰
C ₁₂ = −1.6989 × 10 ⁻²⁴ C ₁₄ = 7.9711 × 10 ⁻²⁹
C ₁₆ = −2.77075 × 10 ⁻³³ C ₁₈ = 0

  FIG. 5 is a diagram showing lateral aberration in the projection optical system of the first example. In the aberration diagrams, Y represents the image height, the solid line represents the center wavelength of 193.3060 nm, the broken line represents 193.306 nm + 0.2 pm = 193.3062 nm, and the alternate long and short dash line represents 193.306 nm−0.2 pm = 193.3058 nm. Yes. Note that the notation in FIG. 5 is the same in FIG. As is apparent from the aberration diagram of FIG. 5, in the first embodiment, a very large image-side numerical aperture (NA = 1.32) and a relatively large effective exposure area ER (26 mm × 5 mm) are secured. Nevertheless, it can be seen that the aberration is well corrected for exposure light having a wavelength width of 193.306 nm ± 0.2 pm.

[Second Embodiment]
FIG. 6 is a diagram showing a lens configuration of the projection optical system according to the second example of the present embodiment. Referring to FIG. 6, in the projection optical system PL according to the second example, the first imaging optical system G1 is arranged in order from the reticle side, with a plane parallel plate P1, a biconvex lens L11, and a positive surface with a convex surface facing the reticle side. A meniscus lens L12, a positive meniscus lens L13 having a convex surface facing the reticle, a biconcave lens L14 having an aspheric concave surface facing the reticle, a positive meniscus lens L15 having a convex surface facing the reticle, and a reticle side A positive meniscus lens L16 having a concave surface, a negative meniscus lens L17 having a concave surface facing the reticle side, a positive meniscus lens L18 having an aspheric concave surface facing the reticle side, and a positive meniscus lens having a concave surface facing the reticle side L19, a biconvex lens L110, and a positive meniscus lens L111 having an aspheric concave surface facing the wafer side. To have.

  The second imaging optical system G2 includes a negative meniscus lens L21 having a concave surface on the reticle side and a negative meniscus having a concave surface on the reticle side in order from the reticle side (that is, the incident side) along the light traveling path. The lens L22 includes a concave reflecting mirror CM having a concave surface facing the reticle. Further, the third imaging optical system G3 includes, in order from the reticle side (that is, the incident side), a positive meniscus lens L31 having a concave surface facing the reticle side, a biconvex lens L32, and a positive meniscus lens L33 having a convex surface facing the reticle side. A positive meniscus lens L34 having an aspherical concave surface facing the wafer, a biconcave lens L35, a biconcave lens L36 having an aspherical concave surface facing the wafer, and an aspherical concave surface facing the reticle. A positive meniscus lens L37, a positive meniscus lens L38 having an aspheric concave surface facing the wafer, a plano-concave lens L39 having an aspheric concave surface facing the wafer, and an aspheric concave surface facing the reticle. Positive meniscus lens L310, positive meniscus lens L311 having a concave surface facing the reticle, aperture stop AS, and flat surface facing the wafer side A lens L312; a positive meniscus lens L313 with an aspherical concave surface facing the wafer; a positive meniscus lens L314 with an aspherical concave surface facing the wafer; and a planoconvex lens L315 (boundary) facing the wafer side The lens Lb) and a plane parallel plate Lp.

  In the second embodiment, as in the first embodiment, use light (exposure light) is used in the optical path between the boundary lens Lb and the plane parallel plate Lp and in the optical path between the plane parallel plate Lp and the wafer W. Pure water (Lm1, Lm2) having a refractive index of 1.435876 with respect to ArF excimer laser light (center wavelength λ = 193.306 nm) is filled. Further, all the light transmitting members including the boundary lens Lb and the plane parallel plate Lp are made of quartz having a refractive index of 1.5603261 with respect to the center wavelength of the used light. 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 = 193.306 nm
β = 1/4
NA = 1.3
B = 15.4mm
A = 3mm
LX = 26mm
LY = 5mm

(Optical member specifications)
Surface number r dn optical member (reticle surface) 128.0298
1 ∞ 8.0000 1.5603261 (P1)
2 ∞ 3.0000
3 708.58305 50.0000 1.5603261 (L11)
4 -240.96139 1.0000
5 159.28256 55.0000 1.5603261 (L12)
6 1030.42583 15.3309
7 175.91680 33.4262 1.5603261 (L13)
8 1901.42936 13.4484
9 * -313.76486 11.8818 1.5603261 (L14)
10 235.56199 1.0000
11 90.40801 53.3442 1.5603261 (L15)
12 109.36394 12.8872
13 -1337.13410 20.2385 1.5603261 (L16)
14 -314.47144 10.2263
15 -106.13528 42.5002 1.5603261 (L17)
16 -334.97792 56.0608
17 * -1619.43320 46.3634 1.5603261 (L18)
18 -167.00000 1.0000
19 -568.04127 48.4966 1.5603261 (L19)
20 -172.67366 1.0000
21 637.03167 27.8478 1.5603261 (L110)
22 -838.93167 1.0000
23 264.56403 30.7549 1.5603261 (L111)
24 * 3443.52617 72.0000
25 ∞ -237.1956 (M1)
26 134.07939 -15.0000 1.5603261 (L21)
27 218.66017 -33.2263
28 111.51192 -18.0000 1.5603261 (L22)
29 334.92606 -28.5215
30 170.92067 28.5215 (CM)
31 334.92606 18.0000 1.5603261 (L22)
32 111.51192 33.2263
33 218.66017 15.0000 1.5603261 (L21)
34 134.07939 237.1956
35 ∞ -72.0000 (M2)
36 1133.17643 -25.2553 1.5603261 (L31)
37 247.47802 -1.0000
38 -480.60890 -29.6988 1.5603261 (L32)
39 626.43077 -1.0000
40 -208.29831 -36.2604 1.5603261 (L33)
41 -2556.24930 -1.0000
42 -173.46230 -50.0000 1.5603261 (L34)
43 * -294.18687 -26.4318
44 699.54032 -11.5000 1.5603261 (L35)
45 -106.38847 -47.9520
46 158.19938 -11.5000 1.5603261 (L36)
47 * -189.99848 -27.6024
48 * 487.32943 -34.3282 1.5603261 (L37)
49 153.21216 -1.0000
50 -280.33475 -39.4036 1.5603261 (L38)
51 * -1666.66667 -17.3862
52 ∞ -22.0000 1.5603261 (L39)
53 * -1511.71580 -40.3150
54 * 655.86673 -62.2198 1.5603261 (L310)
55 242.88510 -1.0000
56 843.73059 -49.2538 1.5603261 (L311)
57 280.00000 -1.0000
58 ∞ -1.0000 (AS)
59 -291.92686 -61.1038 1.5603261 (L312)
60 ∞ -1.0000
61 -179.32463 -67.4474 1.5603261 (L313)
62 * -438.34656 -1.0000
63 -128.42402 -52.4156 1.5603261 (L314)
64 * -401.88080 -1.0000
65 -75.86112 -41.5893 1.5603261 (L315: Lb)
66 ∞ -1.0000 1.435876 (Lm2)
67 ∞ -16.5000 1.5603261 (Lp)
68 ∞ -3.0000 1.435876 (Lm1)
(Wafer surface)

(Aspheric data)
9 faces κ = 0
C ₄ = −3.1753 × 10 ⁻⁸ C ₆ = 9.0461 × 10 ⁻¹²
C ₈ = −1.0355 × 10 ⁻¹⁵ C ₁₀ = 1.2398 × 10 ^{−19
_{C 12 = -1.1221 × 10 -23 C}} 14 = 5.7476 × 10 -28
C ₁₆ = −1.1800 × 10 ⁻³² C ₁₈ = 0

17 faces κ = 0
C ₄ = −2.8399 × 10 ⁻⁸ C ₆ = −3.0401 × 10 ⁻¹³
C ₈ = 1.1462 × 10 ⁻¹⁷ C ₁₀ = 4.0639 × 10 ⁻²²
C ₁₂ = −8.6125 × 10 ⁻²⁶ C ₁₄ = 4.4202 × 10 ⁻³⁰
C ₁₆ = −9.9158 × 10 ⁻³⁵ C ₁₈ = 0

24 surfaces κ = 0
C ₄ = 2.1499 × 10 ⁻⁸ C ₆ = −3.8886 × 10 ⁻¹³
C ₈ = 5.4812 × 10 ⁻¹⁸ C ₁₀ = −2.1623 × 10 ⁻²³
C ₁₂ = −2.5636 × 10 ⁻²⁶ C ₁₄ = 2.1879 × 10 ⁻³⁰
C ₁₆ = −6.5039 × 10 ⁻³⁵ C ₁₈ = 0

43 planes κ = 0
^{_{C 4 = -2.0533 × 10 -8 C}} 6 = 7.8051 × 10 -13
C ₈ = 9.4002 × 10 ⁻¹⁸ C ₁₀ = −2.01043 × 10 ⁻²¹
C ₁₂ = 7.8182 × 10 ⁻²⁵ C ₁₄ = −9.2007 × 10 ⁻²⁹
C ₁₆ = 3.6742 × 10 ⁻³³ C ₁₈ = 0

47 faces κ = 0
C ₄ = 9.8639 × 10 ⁻⁸ C ₆ = −6.7359 × 10 ⁻¹²
C ₈ = 6.8579 × 10 ⁻¹⁶ C ₁₀ = −6.1604 × 10 ⁻²⁰
C ₁₂ = 5.1722 × 10 ⁻²⁴ C ₁₄ = −2.9412 × 10 ⁻²⁸
C ₁₆ = 8.6688 × 10 ⁻³³ C ₁₈ = 0

48 faces κ = 0
C ₄ = 4.3101 × 10 ⁻⁸ C ₆ = −3.2805 × 10 ⁻¹²
C ₈ = 5.6432 × 10 ⁻¹⁷ C ₁₀ = −9.2345 × 10 ^{−22
_{C 12 = 1.0713 × 10 -25 C}} 14 = -9.9944 × 10 -30
C ₁₆ = 1.8148 × 10 ⁻³³ C ₁₈ = 0

51 plane κ = 0
C ₄ = 2.5839 × 10 ⁻⁸ C ₆ = −1.8848 × 10 ⁻¹²
C ₈ = −4.9271 × 10 ⁻¹⁷ C ₁₀ = 4.4946 × 10 ⁻²¹
C ₁₂ = −7.2550 × 10 ⁻²⁶ C ₁₄ = 4.9237 × 10 ⁻³¹
C ₁₆ = −2.4260 × 10 ⁻³⁵ C ₁₈ = 6.2565 × 10 ⁻⁴⁰

53 plane κ = 0
C ₄ = −4.7449 × 10 ⁻⁸ C ₆ = −2.33075 × 10 ⁻¹³
C ₈ = 1.0475 × 10 ⁻¹⁶ C ₁₀ = −2.1805 × 10 ⁻²¹
C ₁₂ = −9.0530 × 10 ⁻²⁶ C ₁₄ = 4.6274 × 10 ⁻³⁰
C ₁₆ = −6.4961 × 10 ⁻³⁵ C ₁₈ = 3.4402 × 10 ⁻⁴¹

54 faces κ = 0
C ₄ = 2.0328 × 10 ⁻⁸ C ₆ = −7.7439 × 10 ⁻¹³
C ₈ = 1.6217 × 10 ⁻¹⁷ C ₁₀ = −3.5531 × 10 ⁻²²
C ₁₂ = 8.2634 × 10 ⁻²⁷ C ₁₄ = 2.6232 × 10 ⁻³¹
C ₁₆ = −2.0989 × 10 ⁻³⁵ C ₁₈ = 4.0888 × 10 ⁻⁴⁰

62 plane κ = 0
C ₄ = 2.5121 × 10 ⁻⁸ C ₆ = −2.0342 × 10 ⁻¹²
C ₈ = 1.2906 × 10 ⁻¹⁶ C ₁₀ = −5.4455 × 10 ⁻²¹
C ₁₂ = 1.2885 × 10 ⁻²⁵ C ₁₄ = −1.4600 × 10 ^{−30
_{C 16 = 3.2850 × 10 -36 C}} 18 = 0

64 faces κ = 0
C ₄ = −2.8098 × 10 ⁻⁸ C ₆ = −3.9565 × 10 ⁻¹²
C ₈ = 3.1966 × 10 ⁻¹⁶ C ₁₀ = −2.7246 × 10 ⁻²⁰
C ₁₂ = 1.8266 × 10 ⁻²⁴ C ₁₄ = −8.6244 × 10 ⁻²⁹
C ₁₆ = 2.1570 × 10 ⁻³³ C ₁₈ = 0

  FIG. 7 is a diagram showing transverse aberration in the projection optical system of the second example. As is apparent from the aberration diagram of FIG. 7, in the second embodiment as well, as in the first embodiment, a very large image-side numerical aperture (NA = 1.3) and a relatively large effective exposure area ER (26 mm × 5 mm), the aberration is well corrected for the exposure light having a wavelength width of 193.306 nm ± 0.2 pm.

  Thus, in the projection optical system PL of the present embodiment, a large effective image is obtained by interposing pure water (Lm1, Lm2) having a large refractive index in the optical path between the boundary lens Lb and the wafer W. A relatively large effective imaging area can be secured while securing the side numerical aperture. That is, in each embodiment, a high image-side numerical aperture of about 1.3 is secured for an ArF excimer laser beam having a center wavelength of 193.306 nm, and an effective exposure area (stationary exposure) of 26 mm × 5 mm is obtained. Area) ER can be ensured, and for example, a circuit pattern can be scanned and exposed at a high resolution in a rectangular exposure area of 26 mm × 33 mm.

  In addition, since the immersion projection optical system PL of the present embodiment employs a catadioptric imaging optical system, the Petzval condition is almost satisfied regardless of a large image-side numerical aperture, thereby improving the flatness of the image. It can be obtained, and the effective field (effective illumination area) and effective projection area (effective exposure area ER) adopt an off-axis field-type imaging optical system that does not include the optical axis, so it can handle any pattern Power can be secured.

  However, as described above, in the off-axis visual field projection optical system, a light irradiation region (a region through which an effective imaging light beam passes: irradiation) particularly in a refractive optical element (parallel plane plate, lens, etc.) close to an object or an image. Area) is relatively large from the optical axis. Specifically, in the projection optical system PL of the present embodiment, in particular, a refractive optical element in the vicinity of the reticle R, a surface optically conjugate with the reticle R or its vicinity (that is, the vicinity of the first planar reflecting mirror M1, the second In the refractive optical element in the vicinity of the plane reflecting mirror M2 and in the vicinity of the wafer W), the deviation of the light irradiation region from the optical axis is relatively large.

  If the deviation of the light irradiation region from the optical axis is relatively large, asymmetry is likely to occur in the temperature change in the refractive optical element that has been irradiated with light, and as a result, aberration fluctuations due to shape changes and refractive index changes are likely to occur. It is difficult to correct the aberration variation accompanying the change in shape and refractive index due to the irradiation heat by, for example, a lens control system that drives the refractive optical element up and down.

  Therefore, in the present embodiment, as shown in FIG. 8, for example, a specification in which the deviation from the optical axis of the light irradiation region is relatively large by being arranged in the vicinity of the reticle R, or at a position optically conjugate with the reticle R or in the vicinity thereof. Near the refractive optical element (hereinafter, simply referred to as “specific refractive optical element”) 80, a material having a higher thermal conductivity than the material forming the specific refractive optical element 80 (quartz in this embodiment). A heat conducting member 81 is disposed. As a material having high thermal conductivity for forming the heat conducting member 81, for example, a metal such as titanium or stainless steel, ceramics, or the like can be used.

  In order to simplify and clarify the description, in FIG. 8, refractive optical elements (for example, a parallel plane plate Lp, a boundary lens Lb, a lens L314, etc.) disposed in the vicinity of the wafer W are used as the specific refractive optical element 80. Assumed. The specific refractive optical element 80 has an outer peripheral shape corresponding to a circle centered on the reference optical axis AX (that is, the optical axis AX3), and is held by a predetermined holding mechanism 82 at three points on the outer periphery. Further, the light irradiation area 80a on the specific refractive optical element 80 corresponds to the decentering direction (Y direction; see FIG. 2) of the effective exposure area ER on the wafer W from the optical axis AX. Is eccentric along the Y direction.

  The heat conducting member 81 is a distance from the side close to the light irradiation region 80a of the specific refractive optical element 80 (the right side in the figure: -Y direction side) with respect to the Y direction which is an eccentric direction from the optical axis AX of the light irradiation region 80a. Is arranged to be substantially smaller than the distance from the side far from the light irradiation region 80a (left side in the figure: + Y direction side). Thus, in the specific refractive optical element 80, the temperature on the right side of the specific refractive optical element 80 in the drawing tends to rise initially due to the eccentricity of the light irradiation region 80a from the optical axis AX, but high thermal conductivity is achieved. The heat-conducting member 81 has a temperature that is close to the side of the specific refractive optical element 80 where the temperature is likely to rise (right side in the figure: -Y direction side) and is relatively far from the side where the temperature rise is difficult (left side in the figure: + Y direction side). That is, a space (heat transporting means) is formed in which the amount of heat transferred from the side where the temperature of the specific refractive optical element 80 is likely to rise to the heat conducting member 81 is larger than that on the side where the temperature is difficult to rise. The asymmetry of the temperature change in the specific refractive optical element 80 due to the eccentricity of the irradiation region 80a from the optical axis AX is alleviated by the heat conduction action of the heat conducting member 81, and as a result, the shape change and refraction of the refractive optical element due to the heat of irradiation. Small rate change It is suppressed.

  In this way, in the off-axis field-type catadioptric projection optical system PL of this embodiment, aberration fluctuations due to changes in the shape and refractive index of the refractive optical element due to irradiation heat can be suppressed to a small extent, and thus good optical performance can be obtained even during exposure. Can be maintained. Therefore, in the exposure apparatus of this embodiment, the off-axis visual field type catadioptric projection optical system PL in which the aberration variation due to the change in the shape and refractive index of the refractive optical element due to the irradiation heat is suppressed to be small is used. The pattern can be projected and exposed faithfully and with high accuracy.

  In the above description with reference to FIG. 8, it is assumed that the specific refractive optical element 80 is a refractive optical element that is disposed near the wafer W and has a relatively large deviation from the optical axis of the light irradiation region. However, the present invention is not limited to this, for example, a refractive optical element (for example, a plane parallel plate P1, a lens L11, a lens L12, etc.) disposed near the reticle R and having a relatively large deviation from the optical axis of the light irradiation region, Refracting optical elements (for example, the lens L111, the lens L110, the lens L19, etc.) that are arranged in the vicinity of the first flat reflecting mirror M1 and have a relatively large deviation from the optical axis of the light irradiation region, and the second flat reflecting mirror M2. Similarly, a heat conducting member as shown in FIG. 8 is provided for a refractive optical element (for example, lens L31, lens L32, lens L33, etc.) disposed in the vicinity and having a relatively large deviation from the optical axis of the light irradiation region. The heat fluctuation effect of the heat conducting member can suppress the aberration fluctuation caused by the shape change and refractive index change of the refractive optical element.

  Further, in the three-fold imaging type off-axis visual field type catadioptric optical system as shown in each embodiment, the effective exposure region ER can be set closer to the optical axis AX. It is possible to suppress the deviation from the optical axis of the light irradiation region in the refractive optical element disposed on the optically conjugate surface with the reticle R or in the vicinity thereof, and thereby reduce the asymmetry of the temperature distribution.

  In the above-described embodiment, the pair of deflecting mirrors (M1, M2) is formed into an integral structure, that is, the first planar reflecting mirror M1 and the second planar reflecting mirror M2 are integrally formed as one optical member. A simple configuration is realized. In this case, if a metal film such as aluminum is formed on these reflecting surfaces, a considerable amount of light energy is expected to be absorbed, and the shape of the reflecting surface is deformed by absorbed heat, and the gas (air) around the reflecting surface and the temperature of the lens There is concern about fluctuations in aberrations due to the rise. Therefore, measures should be taken to prevent temperature rise by using a material with high thermal conductivity for the reflective substrate. For example, in a projection optical system that requires a high resolving power of 100 nm or less, surface molding is easy and thermal There is no material with high conductivity.

  Therefore, in the present embodiment, for example, a reflective base material is formed using low thermal expansion glass, thereby suppressing changes in the shape of the reflecting surface due to absorbed heat. Further, the reflective group is arranged so as to be close to or in contact with a surface portion of, for example, 20% or more of the surface area of the reflective substrate (preferably 30% or more of the surface area when a commercially available low thermal expansion glass is used). A heat conduction member made of a material having a higher thermal conductivity than the material is arranged to relieve the temperature rise of the reflecting surface and surrounding gas and lens by releasing the absorbed heat, and as a result aberration caused by the temperature rise Fluctuation is suppressed.

  Specifically, in the present embodiment, as shown in FIG. 9, for example, a reflecting surface (first reflecting surface) of the first planar reflecting mirror M <b> 1 is formed on a first side surface 83 a of a triangular prism-shaped base 83 formed of low thermal expansion glass. ) M1a is formed, and the reflecting surface (second reflecting surface) M2a of the second planar reflecting mirror M2 is formed on the second side surface 83b of the triangular prism-shaped base 83. The triangular prism base 83 is held at a predetermined position in the optical path via a holding member 84 that contacts the third side surface 83c. Further, it is formed of a material having a thermal conductivity higher than that of the base material 83 (for example, a metal such as titanium or stainless steel, ceramics, or the like) in proximity to or in contact with the third side surface 83c of the triangular prism base material 83. A heat conducting member 85 is disposed.

  Thus, in this embodiment, since the triangular prism-shaped base material 83 is formed of the low thermal expansion glass, it is possible to suppress the change in the shape of the reflecting surface due to the absorbed heat. Further, due to the heat conduction action of the heat conduction member 85 arranged so as to be close to or in contact with the third side surface 83c of the triangular prism-shaped base material 83, the absorbed heat is released and the reflecting surfaces (M1a, M2a) and the surrounding gas, It is possible to mitigate the temperature rise of the lens and to suppress aberration fluctuations due to the temperature rise.

  In the above description with reference to FIG. 9, the heat conducting member 85 is disposed so as to be close to or in contact with the third side surface 83 c of the triangular prism-shaped base 83, but as shown in FIG. 9B. In addition to the heat conducting member 85, the end face 83d and 83e of both sides of the triangular prism-like base material 83 are close to or in contact with each other (or close to or in contact with at least one of the end faces), and the same function as the heat conducting member 85 is achieved. It is preferable to arrange the heat conducting member 86 having the same. With this configuration, it is possible to more satisfactorily suppress changes in the shape of the reflecting surface due to absorbed heat and aberration variations due to temperature rise.

  Further, instead of the heat conduction member 85 or in addition to the heat conduction member 85, as shown in FIG. 10, it is possible to arrange a heat conduction member 87 having the same function as the heat conduction member 85. In the configuration shown in FIG. 10, a through hole (or non-through hole) 88 extending from one end face (for example, 83d) of the triangular prism-shaped base material 83 toward the other end face (for example, 83e) is formed. A heat conducting member 87 is disposed in proximity to or in contact with the inner surface of the non-through hole 88. Also in this case, the heat conduction action of the heat conducting member 87 allows the absorbed heat to escape to relieve the temperature rise of the reflecting surfaces (M1a, M2a) and the surrounding gas and lens, thereby suppressing aberration fluctuations due to the temperature rise. Can do. The configuration of FIG. 10 is particularly advantageous when the original usable surface area (side surface 83c and end surfaces 83d and 83e) of the triangular prism-shaped substrate 83 is relatively small.

  Further, as shown in FIG. 11, another heat conducting member 89 may be disposed in the vicinity of the optical surface of the specific refractive optical element 80. As a material having high thermal conductivity for forming the heat conductive member 89, for example, a metal such as titanium or stainless steel, ceramics, or the like can be used in the same manner as the heat conductive member 81.

  In order to simplify and clarify the description, FIG. 11 assumes a refractive optical element (for example, a lens L111, a lens L31, etc.) disposed in the vicinity of a surface conjugate with the reticle as the specific refractive optical element 80. Yes. The specific refractive optical element 80 has an outer peripheral shape corresponding to a circle centered on the reference optical axis AX (optical axis AX1 or AX3), and is held by a predetermined holding mechanism 82 at three points on the outer periphery. In addition, the light irradiation region 80a on the specific refractive optical element 80 is light in an eccentric direction (Y direction; see FIG. 2) from the optical axis AX of the effective exposure region ER on the wafer W or light in an effective field region on the reticle. The optical axis AX is eccentric along the Y direction so as to correspond to the eccentric direction from the axis AX.

  In the modification of FIG. 11, the heat conducting member 81 is disposed so that the distance from the specific refractive optical element 80 is substantially equal. Then, the specific refractive optical element 80 is divided into two parts by the surface including the optical axis AX and the X axis of the specific refractive optical element 80, and the side where the light irradiation region 80a is located is defined as the first region 91, and the opposite region is defined as the first region 91. Assuming that the second region 92 is provided, another heat conducting member 89 is disposed so as to cover the optical surface of the specific refractive optical element 80 on the first region 91 side. In the specific refractive optical element 80, the temperature on the right side of the specific refractive optical element 80 in the drawing tends to rise initially due to the eccentricity of the light irradiation region 80a from the optical axis AX, but high heat as a heat transporting means. Since another heat conducting member 89 having conductivity is close to the side where the temperature of the specific refractive optical element 80 is likely to rise in temperature (right side in the figure: -Y direction side), the first refractive index optical element 80 has a first region 91. The amount of heat transferred to the heat conducting members 81 and 89 is larger than that in the second region 92.

  The heat conducting member 89 has a coefficient of thermal expansion different from that of the optical material forming the specific refractive optical element 80 and is not in contact with the specific refractive optical element 80. That is, a gas is interposed between the heat conducting member 89 and the specific refractive optical element 80, and heat from the specific refractive optical element 80 is conducted to the heat conducting member 89 via the gas. With this configuration, the asymmetry of the temperature change in the specific refractive optical element 80 due to the eccentricity of the light irradiation region 80a from the optical axis AX is relieved by the heat conduction action of the heat conducting members 81 and 89, and as a result, the refraction due to the irradiation heat is reduced. Changes in the shape and refractive index of the optical element can be kept small. That is, it is possible to reduce the bias of the temperature distribution of the specific refractive optical element 80 in a state where no stress is applied to the specific refractive optical element 80, and thus it is possible to prevent aberration variation.

Here, in the first region of the specific refractive optical element 80, the area of the first partial region where the distance from the heat conductive member is 200 μm or less is Sa, and the distance from the heat conductive member in the second region of the specific refractive optical element 80 is Where Sb is the area of the second partial region with an area of 200 μm or less, the distance between the center of the effective field on the first surface and the optical axis is O, and the maximum image height on the second surface is Y.
0.75 <Sa (YO) / Sb (Y + O) <7.5 (1)
It is preferable to satisfy the following conditions.

  Conditional expression (1) indicates the degree of off-axis with respect to the optical axis of the optical system (that is, the degree representing how far the effective field of view on the first surface or the effective exposure area on the second surface deviates from the optical axis AX). ), The condition indicating how much the area of the portion close to the specific refractive optical element 80 of the heat conducting member 89 is biased between the first region and the second region.

  If the lower limit of conditional expression (1) is not reached, the effect of reducing the bias (asymmetry) of the temperature distribution in the specific refractive optical element 80 that has been irradiated with light is reduced, and aberration fluctuations accompanying changes in shape and refractive index. Is not preferred because it tends to occur. It is difficult to correct such aberration variation due to change in shape and refractive index due to irradiation heat, for example, by a lens control system that moves the refractive optical element up and down and tilts. Further, the lower limit value of conditional expression (1) is 1.

  On the other hand, if the upper limit value of the conditional expression (1) is exceeded, the heat of the second region of the specific refractive optical element 80 becomes difficult to escape through the heat conducting member 89, and the temperature increase amount of the specific refractive optical element 80 as a whole becomes too large. It is not preferable. Further, the upper limit value of conditional expression (1) is preferably 5. In the example shown in FIG. 11, the light irradiation region 80a exists only in the first region. However, even when the light irradiation region 80a exists across the first region and the second region, the conditional expression is used. (1) is similarly established.

Hereinafter, specific numerical examples of the modification shown in FIG. 11 will be given.
Diameter of specific refractive optical element 80: 240 mmφ
The area of the second partial region in which the distance from the heat conductive member in the second region is 200 μm or less (in the modification of FIG. 11, the side surface of the specific refractive optical element 80 is close to the heat conductive member 81 with a distance of 200 μm or less, Its width is 5mm):
Sb = 240π × 5/2 = 1888 mm ²

The area of the first partial region where the distance from the heat conducting member in the first region is 200 μm or less (in the modification of FIG. 11, the side surface of the specific refractive optical element 80 is close to the heat conducting member 81 at a distance of 200 μm or less, The width is 5 mm, and the heat conducting member 89 is located 84.85 mm outside the boundary between the first region and the second region):
Sa = 1888 mm ² +4101 mm ² = 5988 mm ²
Distance between optical axis on first surface and center of effective visual field area: O = 6 mm
Maximum image height on the second surface: Y = 16 mm
Sa (YO) / Sb (Y + O) = 1.44

Next, referring to FIGS. 12 to 14, a comparison with a comparative example is performed. FIG. 12 is a diagram schematically showing a configuration of a heat conducting member arranged in the vicinity of the specific refractive optical element according to the comparative example. In the comparative example of FIG. 12, the heat conducting member 81 is arranged so that the distance from the specific refractive optical element 80 is substantially equal. In this comparative example, the area Sa of the first partial region is equal to the area Sb of the second partial region, the distance O between the optical axis on the first surface and the center of the effective visual field region, and the maximum on the second surface. The image height Y is the same value as that of the modification of FIG.
The condition corresponding value in this comparative example is
Sa (YO) / Sb (Y + O) = Sa (16-6) / Sb (16 + 6) = 0.455
It has become.

  FIG. 13 is a contour diagram showing the temperature distribution of the specific refractive optical element 80 when the light irradiation region 80a of the specific refractive optical element 80 is irradiated with light for a predetermined time in the comparative example of FIG. FIG. 14 is a contour diagram showing a temperature distribution of the specific refractive optical element 80 when the light irradiation region 80a of the specific refractive optical element 80 is irradiated with light for the predetermined time in the modification of FIG. In FIG. 13 and FIG. 14, the intervals between the contour lines are equal. Comparing these temperature distribution diagrams, in the comparative example of FIG. 12, the temperature distribution is biased along the Y direction, and the maximum temperature is as high as 22 mK. On the other hand, in the modified example of FIG. 11, the temperature distribution is substantially symmetric with respect to the optical axis, and the maximum temperature is as low as 15 mK. From these comparisons, it is clear that the temperature distribution of the specific refractive optical element can be made close to optical axis symmetry (rotation symmetry) by satisfying conditional expression (1). Note that the modification of FIG. 11 and the embodiment of FIG. 8 may be combined.

  Further, as shown in FIG. 15, a substance 93 having a higher thermal conductivity than gas may be interposed as a heat transport means between the specific refractive optical element 80 and the heat conducting member 81. Fluorine greases such as VARIELTA from NOK CRUBER Co., Ltd., Krytox from DuPont, Fomblin from Augmont, and DEMNUM from Daikin Industries, Ltd. are used as materials having higher thermal conductivity than gas. be able to.

  For simplification and clarification of explanation, FIG. 15 assumes that the specific refractive optical element 80 is a refractive optical element (for example, a lens L111, a lens L31, etc.) disposed in the vicinity of a plane conjugate with the reticle. Yes. The specific refractive optical element 80 has an outer peripheral shape corresponding to a circle centered on the reference optical axis AX (optical axis AX1 or AX3), and is held by a predetermined holding mechanism 82 at three points on the outer periphery. In addition, the light irradiation region 80a on the specific refractive optical element 80 is light in an eccentric direction (Y direction; see FIG. 2) from the optical axis AX of the effective exposure region ER on the wafer W or light in an effective field region on the reticle. The optical axis AX is eccentric along the Y direction so as to correspond to the eccentric direction from the axis AX.

  Also in the modification of FIG. 15, the heat conducting member 81 is arranged so that the distance from the specific refractive optical element 80 is substantially equal. Then, the specific refractive optical element 80 is divided into two parts by the surface including the optical axis AX and the X axis of the specific refractive optical element 80, and the side where the light irradiation region 80a is located is defined as the first region 91, and the opposite region is defined as the first region 91. Assuming that the two regions 92 are used, a variel is encapsulated as a substance 93 having a higher thermal conductivity than gas on the side surface of the specific refractive optical element 80 on the first region 91 side. With this configuration, the amount of heat transferred from the first region 91 of the specific refractive optical element 80 to the heat conducting member 81 is larger than that of the second region 92. With this configuration, the asymmetry of the temperature change in the specific refractive optical element 80 due to the eccentricity from the optical axis AX of the light irradiation region 80a is alleviated by the thermal conduction action of the substance 93 having a higher thermal conductivity than that of the gas. Changes in the shape and refractive index of the refractive optical element due to irradiation heat can be kept small.

  In the modification of FIG. 15, since the liquid is used as the substance 93 having a high thermal conductivity, the heat in the specific refractive optical element 80 is transferred to the liquid 93 without applying stress to the specific refractive optical element 80. It is possible to conduct to the heat conducting member 81 through. That is, it is possible to reduce the bias of the temperature distribution of the specific refractive optical element 80 in a state where no stress is applied to the specific refractive optical element 80, and thus it is possible to prevent aberration variation. Note that the thermal conductivity of the varielta as the material 93 having high thermal conductivity is 0.11 [W / (K · m)], the thermal conductivity of air is 0.02637 [W / (K · m)], The thermal conductivity of nitrogen is 0.0260 [W / (K · m)].

  Next, referring to FIGS. 15 and 16, a comparison with the comparative example shown in FIGS. 12 and 13 is performed. FIG. 16 is a contour diagram showing the temperature distribution of the specific refractive optical element 80 when the light irradiation region 80a of the specific refractive optical element 80 is irradiated with light for a predetermined time in the modification of FIG. Here, in FIG. 16 and FIG. 13, the interval between the contour lines is equal. Comparing the temperature distribution diagrams shown in FIG. 13 and FIG. 16, in the comparative example of FIG. 12, the temperature distribution is biased along the Y direction, whereas in the modified example of FIG. Symmetric. From these comparisons, the temperature distribution of the specific refractive optical element is symmetric with respect to the optical axis (rotationally symmetric) by interposing a substance 93 having higher thermal conductivity than gas between the specific refractive optical element 80 and the heat conducting member 81. It is clear that 15 may be combined with the embodiment of FIG. 8 and / or the modification of FIG.

  In the above-described embodiment, the present invention is applied to the three-fold imaging type off-axis visual field type catadioptric optical system as shown in each example. However, the present invention is not limited to this. The present invention can also be applied to a catadioptric projection optical system that includes at least one concave reflecting mirror and a plurality of refractive optical elements and has an effective field of view and an effective projection area decentered from the optical axis. Specifically, for example, a first optical unit having at least one refractive optical element disposed in an optical path between the reticle R (object plane) and the wafer W (image plane), the first optical unit, and the wafer A second optical unit disposed in the optical path between the second optical unit and including at least one concave reflecting mirror; and at least one refractive optical element disposed in the optical path between the second optical unit and the wafer W. A third optical unit, a first deflecting mirror (first reflecting surface) disposed in an optical path between the first optical unit and the second optical unit, and between the second optical unit and the third optical unit. A second deflecting mirror (second reflecting surface) disposed in the optical path, and an intermediate image of the reticle R (object) is formed in the optical path between the second optical unit and the third optical unit 2. The present invention is also applicable to a catadioptric optical system of a refocusing type. It can be. In this case, for example, the above-described effect of the present invention can be obtained by providing the heat conducting member 81 in the specific refractive optical element in at least one of the first optical unit and the third optical unit.

  Further, the embodiment of FIG. 8, the modified example of FIG. 11, and the modified example of FIG. 15 are not limited to the off-axis visual field type catadioptric optical system having a plurality of optical axes, for example, one optical axis. An off-axis visual field type comprising: an even number of curved mirrors including at least one concave reflecting mirror disposed along the optical axis; and a plurality of refractive optical elements disposed along the optical axis. This can also be applied to the coaxial catadioptric optical system. A specific description will be given with reference to FIG. 17 showing the lens configuration of the off-axis visual field type coaxial catadioptric optical system.

  Referring to FIG. 17, the projection optical system PL, which is an off-axis visual field type coaxial reflection / refraction optical system, forms a first intermediate image IM1 of the pattern of the reticle R arranged on the object surface (first surface). Based on the light from the first imaging optical system (first optical unit) G1 and the first intermediate image IM1, the second intermediate image IM2 of the reticle pattern (the image of the first intermediate image IM1 and the reticle pattern 2) A second image forming optical system (second optical unit) G2 for forming a next image) and a reticle pattern on a wafer W arranged on the image surface (second surface) based on light from the second intermediate image IM2. And a third imaging optical system (third optical unit) G3 for forming a final image (a reduced image of the reticle pattern). In the example of FIG. 17, both the first imaging optical system G1 and the second imaging optical system G2 are catadioptric optical systems including concave reflecting mirrors (CM1, CM3, CM4), and the third imaging optical system G3. Is a refractive optical system.

  The first imaging optical system G1 is disposed in the vicinity of the lens L11 as a field lens group disposed on the most reticle side, the concave reflecting mirror CM1, the convex reflecting mirror CM2, and the first intermediate image IM1. Lenses L12 and L13 are provided as intermediate image field lens groups. These optical elements L11 to L13, CM1, and CM2 are disposed along the optical axis AX of the projection optical system PL. Here, the convex reflecting mirror CM2 may be a plane mirror or a concave reflecting mirror. Further, the first intermediate image IM1 does not need to be formed on the exit side of the intermediate image field lens group, and may be formed on the incident side of the intermediate image field lens group or in the intermediate image field lens group.

  The second imaging optical system G2 includes two concave reflecting mirrors CM3 and CM4, negative lenses L21 and L23 provided in the vicinity of each concave reflecting mirror, and two concave reflecting mirrors CM3 and CM4 (two And a lens L22 disposed in the optical path between the negative lenses L21 and L23. Here, the two negative lenses L21 and L23 are lenses arranged in the reciprocating optical path, and the lens L22 is a lens arranged in the triple optical path. Here, the optical elements L21 to L23, CM3 and CM4 constituting the second imaging optical system G2 are also arranged along the optical axis AX of the projection optical system PL. The third imaging optical system G3 includes a plurality of lenses L31 to L313 disposed along the optical axis AX of the projection optical system PL, and an aperture stop AS.

  In the modification of FIG. 17, the optical element (lens L11) close to the object (reticle R), the optical element close to the image (lens L313), or close to the intermediate images IM1 and IM2 (close to a position conjugate with the object). In the optical element (lenses L12, L13, L31 to L36), the deviation of the light irradiation region from the optical axis AX is relatively large. Here, by applying the embodiment of FIG. 8, the modified example of FIG. 11, and the modified example of FIG. 15 to these optical elements, the aberration caused by the shape change or refractive index change of the refractive optical element due to irradiation heat. Variations can be kept small. In the modification of FIG. 17, unlike the embodiments shown in FIGS. 4 and 6, the parallel flat plate arranged on the most reticle side and the parallel flat plate arranged on the most image side are not provided. These plane parallel plates may be provided.

  By the way, in the above-described embodiment, since the plane parallel plate (generally an optical member having almost no refractive power) Lp is disposed in the optical path between the boundary lens Lb and the wafer W, pure water as immersion liquid is used. Even if it is contaminated by outgas or the like from the photoresist applied to the wafer W, the image of the boundary lens Lb due to the contaminated pure water is caused by the action of the parallel flat plate Lp interposed between the boundary lens Lb and the wafer W. Contamination of the side optical surface can be effectively prevented. Furthermore, since the difference in refractive index between the liquid (pure water: Lm1, Lm2) and the plane parallel plate Lp is small, the posture and position accuracy required for the plane parallel plate Lp are greatly relaxed. Even if it is contaminated, the optical performance can be easily restored by replacing the member as needed. Further, the action of the parallel flat plate Lp in the liquid suppresses the pressure fluctuation at the time of scan exposure of the liquid Lm2 in contact with the boundary lens Lb and the pressure fluctuation at the time of step movement, so that the liquid can be held in a relatively small space. It becomes possible. However, it is not limited to the configuration of the above-described embodiment, and a configuration in which the installation of the plane parallel plate Lp is omitted is also possible.

  In the above-described embodiment, the present invention is applied to the immersion type projection optical system. However, the present invention is not limited to this, and a dry type in which no liquid is interposed in the optical path between the image plane and the image plane. The present invention can be similarly applied to the projection optical system.

  In the exposure apparatus of the above-described embodiment, the reticle (mask) is illuminated by the illumination device (illumination process), and the transfer pattern formed on the mask is exposed to the photosensitive substrate using the projection optical system (exposure process). Thus, a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. Hereinafter, referring to the flowchart of FIG. 18 for an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of this embodiment. I will explain.

  First, in step 301 of FIG. 18, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the one lot of wafers. Thereafter, in step 303, using the exposure apparatus of the present embodiment, the image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot via the projection optical system. Thereafter, in step 304, the photoresist on the one lot of wafers is developed, and in step 305, the resist pattern is etched on the one lot of wafers to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each wafer.

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

  In the exposure apparatus of this embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. In FIG. 19, in a pattern forming process 401, a so-called photolithography process is performed in which a mask pattern is transferred and exposed to a photosensitive substrate (such as a glass substrate coated with a resist) using the exposure apparatus of the present embodiment. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step 402.

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

  In the cell assembly step 403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step 401 and the color filter obtained in the color filter formation step 402, and a liquid crystal panel (liquid crystal cell) is obtained. ). Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having an extremely fine circuit pattern can be obtained with high throughput.

In the above-described embodiment, the ArF excimer laser light source is used. However, the present invention is not limited to this, and other appropriate light sources such as an F ₂ laser light source can also be used. However, when F ₂ laser light is used as exposure light, a fluorine-based liquid such as fluorine-based oil or perfluorinated polyether (PFPE) that can transmit the F ₂ laser light is used as the liquid.

  In the above-described embodiment, the present invention is applied to the projection optical system mounted on the exposure apparatus. However, the present invention is not limited to this, and other general catadioptric projection optical systems are used. The present invention can be applied.

  In the above-described embodiment, the boundary lens Lb and the liquid parallel flat plate Lp are formed of quartz. However, the material forming the boundary lens Lb and the liquid parallel flat plate Lp is not limited to quartz. Crystal materials such as magnesium, calcium oxide, strontium oxide, and barium oxide may be used.

In the above-described embodiment, pure water is used as the first liquid and the second liquid. However, the first and second liquids are not limited to pure water. For example, H ⁺ , Cs ⁺ , K ⁺ , Cl ^-, SO ₄ ^2-, can be used water put PO ₄ ^2-a, isopropanol, glycerol, hexane, heptane, decane and the like.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows the positional relationship of the rectangular-shaped still exposure area | region formed on a wafer in this embodiment, and a reference | standard optical axis. It is a figure which shows typically the structure between the boundary lens and wafer in each Example of this embodiment. It is a figure which shows the lens structure of the projection optical system concerning the 1st Example of this embodiment. It is a figure which shows the lateral aberration in the projection optical system of 1st Example. It is a figure which shows the lens structure of the projection optical system concerning 2nd Example of this embodiment. It is a figure which shows the lateral aberration in the projection optical system of 2nd Example. It is a figure which shows roughly the structure of the heat conductive member arrange | positioned in the vicinity of a specific refractive optical element. It is a figure which shows schematically the structure of the heat conductive member arrange | positioned in the vicinity or contact of the side surface and end surface of a triangular prism base material. It is a figure which shows roughly the structure of the heat conductive member arrange | positioned in the proximity | contact or contact of the inner surface of the hole extended toward the other end surface from one end surface of a triangular prism base material. It is a figure which shows roughly the modification which has arrange | positioned another heat conductive member adjacent to the optical surface of a specific refractive optical element. It is a figure which shows roughly the structure of the heat conductive member arrange | positioned in the vicinity of the specific refractive optical element concerning a comparative example. FIG. 13 is a contour diagram showing a temperature distribution of a specific refractive optical element when light is irradiated on a light irradiation region of the specific refractive optical element for a predetermined time in the comparative example of FIG. FIG. 12 is a contour diagram showing a temperature distribution of a specific refractive optical element when light is irradiated on a light irradiation region of the specific refractive optical element for a predetermined time in the modification of FIG. 11. It is a figure which shows roughly the modification which interposes the substance whose heat conductivity is higher than gas as a heat transport means between a specific refractive optical element and a heat conductive member. FIG. 16 is a contour diagram showing a temperature distribution of a specific refractive optical element when light is irradiated on a light irradiation region of the specific refractive optical element for a predetermined time in the modification of FIG. 15. It is a figure which shows roughly the lens structure of the off-axis visual field type | mold coaxial reflection / refraction optical system which can apply this invention. It is a flowchart of the method at the time of obtaining the semiconductor device as a microdevice. It is a flowchart of the method at the time of obtaining the liquid crystal display element as a microdevice.

Explanation of symbols

R reticle RST reticle stage PL projection optical system Lb boundary lens Lp parallel flat plates Lm1, Lm2 pure water (liquid)
W Wafer 1 Illumination optical system 9 Z stage 10 XY stage 12 Moving mirror 13 Wafer laser interferometer 14 Main control system 15 Wafer stage drive system 21 First water supply / drainage mechanism 22 Second water supply / drainage machine 81, 85, 87 Thermal conduction member

Claims (20)

In a projection optical system for forming an image in the effective field of view of the first surface in an effective projection area on the second surface,
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
The projection optical system includes at least one specific refractive optical element and a heat conduction formed by a material having a higher thermal conductivity than a material that is disposed in the vicinity of the specific refractive optical element and forms the specific refractive optical element. With members,
The light irradiation area on the specific refractive optical element is decentered from the optical axis of the specific refractive optical element along a direction corresponding to the one axial direction at the position of the specific refractive optical element,
Dividing the specific refractive optical element into a first region and a second region opposite to the first refractive index optical element by a plane including the optical axis of the specific refractive optical element and the other of the two orthogonal axes. Is the first region, the amount of heat transferred from the first region of the specific refractive optical element to the heat conducting member is transferred from the second region of the specific refractive optical element to the heat conducting member. A projection optical system, further comprising heat transport means for making the amount of heat to move larger. The heat transport means includes a space between the specific refractive optical element and the heat conducting member,
The space has a distance between the heat conducting member on the first region side and the specific refractive optical element on the second region side in a direction corresponding to the one axial direction at the position of the specific refractive optical element. The projection optical system according to claim 1, wherein the projection optical system has a shape smaller than the distance. 3. The projection optical system according to claim 1, wherein the heat transporting unit includes a heat conducting member facing an optical surface on the first region side of the specific refractive optical element. The heat transporting means is disposed between the surface of the specific refractive optical element in the first region and the heat conducting member, and has a substance having a higher thermal conductivity than gas. 4. The projection optical system according to any one of items 1 to 3. The projection optical system according to claim 4, wherein the substance having a higher thermal conductivity than the gas is grease. In a projection optical system that projects an image of a first surface onto a second surface,
The projection optical system includes at least one concave reflecting mirror and a plurality of refractive optical elements, and forms an image in an effective field on the first surface in an effective projection area on the second surface;
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
The effective projection area on the second surface is eccentric from the optical axis along an axial direction on the second surface corresponding to the one axial direction;
In the vicinity of at least one specific refractive optical element among the plurality of refractive optical elements, a heat conductive member formed of a material having a higher thermal conductivity than a material forming the specific refractive optical element is disposed,
The heat conducting member has a distance from a side closer to the light irradiation region of the specific refractive optical element with respect to a direction corresponding to the one axial direction at the position of the specific refractive optical element. A projection optical system, wherein the projection optical system is arranged so as to be smaller than the distance. In the projection optical system for forming an image of the first surface on the second surface,
Comprising at least one concave reflecting mirror and a plurality of refractive optical elements, forming an image in an effective field on the first surface in an effective projection area on the second surface;
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
In the vicinity of at least one specific refractive optical element among the plurality of refractive optical elements, a heat conductive member formed of a material having a higher thermal conductivity than a material forming the specific refractive optical element is disposed,
Dividing the specific refractive optical element into a first region and a second region opposite to the first refractive index optical element by a plane including the optical axis of the specific refractive optical element and the other of the two orthogonal axes. Is the first region, the area of the first partial region in the first region of the specific refractive optical element in which the distance from the heat conducting member is 200 μm or less is Sa, and the specific refraction In the second region of the optical element, the area of the second partial region in which the distance from the heat conducting member is 200 μm or less is Sb, the distance between the center of the effective field on the first surface and the optical axis is O, When the maximum image height on the second surface is Y,
0.75 <Sa (YO) / Sb (Y + O) <7.5
A projection optical system characterized by satisfying the following conditions. In the projection optical system for forming an image of the first surface on the second surface,
Comprising at least one concave reflecting mirror and a plurality of refractive optical elements, forming an image in an effective field on the first surface in an effective projection area on the second surface;
The effective field of view on the first surface is decentered from the optical axis of the projection optical system along one of the two axial directions orthogonal to each other on the first surface;
In the vicinity of at least one specific refractive optical element among the plurality of refractive optical elements, a heat conductive member formed of a material having a higher thermal conductivity than a material forming the specific refractive optical element is disposed,
Dividing the specific refractive optical element into a first region and a second region opposite to the first refractive index optical element by a plane including the optical axis of the specific refractive optical element and the other of the two orthogonal axes. When the first region is the wider region through which
A projection optical system, wherein a substance having a thermal conductivity higher than that of a gas is disposed between the surface of the refractive optical element in the first region and the heat conducting member. The projection optical system is
A first optical unit disposed in an optical path between the first surface and the second surface and having at least one of the plurality of refractive optical elements;
A second optical unit disposed in an optical path between the first optical unit and the second surface and including the at least one concave reflecting mirror;
A third optical unit disposed in an optical path between the second optical unit and the second surface and having at least one of the plurality of refractive optical elements;
The projection according to any one of claims 6 to 8, wherein at least one of the first optical unit and the third optical unit includes the specific refractive optical element. Optical system. The projection optical system is
A first deflecting mirror disposed in an optical path between the first optical unit and the second optical unit;
The projection optical system according to claim 9, further comprising a second deflecting mirror disposed in an optical path between the second optical unit and the third optical unit. The specific refractive optical element is at any one of a position in the vicinity of the first surface, a position in the vicinity of the second surface, and a position in the vicinity of a position optically conjugate with the first surface. The projection optical system according to claim 1, wherein the projection optical system is positioned. In a projection optical system that projects an image of a first surface onto a second surface,
A first optical unit having at least one refractive optical element disposed in an optical path between the first surface and the second surface;
A second optical unit disposed in an optical path between the first optical unit and the second surface and including at least one concave reflecting mirror;
A third optical unit having a plurality of refractive optical elements disposed in an optical path between the second optical unit and the second surface;
A first reflecting surface disposed on the first side surface of the triangular prism-shaped base material, disposed in the optical path between the first optical unit and the second optical unit;
A second reflecting surface that is disposed in the optical path between the second optical unit and the third optical unit, and is formed on a second side surface of the triangular prism-shaped substrate;
A projection optical device comprising: a heat conducting member disposed near or in contact with the third side surface of the base material and formed of a material having a higher thermal conductivity than the base material. system. The projection optical system according to claim 12, wherein the heat conducting member is disposed in proximity to or in contact with at least one end face of the triangular prism base. In a projection optical system that projects an image of a first surface onto a second surface,
A first optical unit having at least one refractive optical element disposed in an optical path between the first surface and the second surface;
A second optical unit disposed in an optical path between the first optical unit and the second surface and including at least one concave reflecting mirror;
A third optical unit having a plurality of refractive optical elements disposed in an optical path between the second optical unit and the second surface;
A first reflecting surface disposed on the first side surface of the triangular prism-shaped base material, disposed in the optical path between the first optical unit and the second optical unit;
A second reflecting surface that is disposed in the optical path between the second optical unit and the third optical unit, and is formed on a second side surface of the triangular prism-shaped base material;
A through hole or a non-through hole extending from one end face toward the other end face is formed in the triangular prism-shaped base material,
It further includes a heat conducting member that is disposed close to or in contact with the inner side surface of the through hole or the inner side surface of the non-through hole and is formed of a material having a higher thermal conductivity than the base material. A projection optical system characterized by that. 15. The projection optical system according to claim 12, wherein the triangular prism base is made of low thermal expansion glass. The projection optical system according to claim 9, wherein an intermediate image of the first surface is formed in an optical path between the second optical unit and the third optical unit. system. The first optical unit has a first imaging optical system for forming a first intermediate image based on light from the first surface,
The second optical unit has a second imaging optical system for forming a second intermediate image based on light from the first intermediate image,
17. The third optical unit has a refractive third imaging optical system for forming a third intermediate image based on light from the second intermediate image. The projection optical system according to claim 1. When the refractive index of the gas in the optical path of the projection optical system is 1, the optical path between the projection optical system and the second surface is filled with a liquid having a refractive index greater than 1.1. The projection optical system according to claim 1, wherein: 19. The method according to claim 1, wherein an image of the pattern is projected onto a photosensitive substrate set on the second surface based on illumination light from a predetermined pattern set on the first surface. An exposure apparatus comprising the projection optical system according to the item. A setting step of setting a predetermined pattern on the first surface;
Based on illumination light from the predetermined pattern, an image of the pattern is projected onto the photosensitive substrate set on the second surface via the projection optical system according to any one of claims 1 to 18. An exposure method comprising exposing an exposure step.

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