JP2014194552A - Cata-dioptric type projection optical system, exposure device, and exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relatively compact projection optical system having superior imaging performance having various aberrations such as a chromatic aberration and a field curvature excellently corrected, and capable of securing a large effective image-side numerical aperture by excellently suppressing reflection loss on an optical plane.SOLUTION: A cata-dioptric type projection optical system for forming a reduced image of a first plane R on a second plane W comprises at least two reflecting mirrors CM1 and CM2 and transparent members L11 to L217. The cata-dioptric type projection optical system comprises an arcuate effective imaging region not including an optical axis AX of the projection optical system. In the cata-dioptric type projection optical system, a condition of 1.05<R/Y0<12 is satisfied, where R is size of a radius of curvature of an arc defining the effective imaging region and Y0 is a maximum image height on the second plane.

Description

  The present invention relates to a catadioptric projection optical system, an exposure apparatus, and an exposure method, and in particular, high-resolution reflection suitable for an exposure apparatus used when manufacturing a semiconductor element or a liquid crystal display element in a photolithography process. The present invention relates to a refractive projection optical system.

  Projection exposure that exposes a mask (or reticle) pattern image onto a wafer (or glass plate or the like) coated with a photoresist or the like via a projection optical system in a photolithography process for manufacturing a semiconductor element or the like. The device is in use. As the degree of integration of semiconductor elements and the like improves, the resolving power (resolution) required for the projection optical system of the projection exposure apparatus is increasing.

  As a result, in order to satisfy the demand 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 · sin θ, where n is the refractive index of a medium (usually gas such as air) between the projection optical system and the image plane, and θ is the maximum incident angle to the image plane. It is represented by

  In this case, if the numerical aperture NA is increased by increasing the maximum incident angle θ, the incident angle on the image plane and the exit angle from the projection optical system increase, and the reflection loss on the optical surface increases. A large effective image-side numerical aperture cannot be ensured. Therefore, a technique for increasing the numerical aperture NA by filling a medium such as a liquid having a high refractive index in the optical path between the projection optical system and the image plane is known.

  However, when this technology is applied to a normal refractive projection optical system, it is difficult to correct chromatic aberration well or to correct field curvature satisfactorily while satisfying Petzval conditions, and an increase in the size of the optical system can be avoided. There was no inconvenience. Further, there is a disadvantage that it is difficult to secure a large effective image-side numerical aperture by satisfactorily suppressing reflection loss on the optical surface.

  The present invention has been made in view of the above-described problems, and has excellent imaging performance by satisfactorily correcting various aberrations such as chromatic aberration and curvature of field and suppressing reflection loss on an optical surface. It is an object of the present invention to provide a relatively small projection optical system capable of securing a large effective image-side numerical aperture. The present invention also provides an exposure apparatus capable of transferring and exposing a fine pattern with high accuracy through a projection optical system having excellent imaging performance and having a large effective image-side numerical aperture and thus high resolution. And an exposure method.

In order to solve the above problems, in the first embodiment of the present invention, in a catadioptric projection optical system that forms a reduced image of the first surface on the second surface,
The projection optical system includes at least two reflecting mirrors, and a boundary lens whose first surface side has a positive refractive power,
When the refractive index of the atmosphere in the optical path of the projection optical system is 1, the boundary lens and the second lens
The optical path between the surfaces is filled with a medium having a refractive index greater than 1.1,
All the transmissive members constituting the projection optical system and all the reflective members having refractive power are arranged along a single optical axis,
The projection optical system includes a projection optical system having an effective imaging region having a predetermined shape that does not include the optical axis. The medium is preferably a fluid. More preferably, the medium is a liquid.

  According to a preferred aspect of the first aspect, the at least two reflecting mirrors include at least one concave reflecting mirror. The projection optical system preferably has an even number of reflecting mirrors. The exit pupil of the projection optical system preferably has no shielding area. In addition, it is preferable that all effective image forming regions of the projection optical system exist in regions outside the optical axis.

  According to a preferred aspect of the first aspect, the projection optical system includes at least two reflecting mirrors, a first imaging optical system for forming an intermediate image of the first surface, and the intermediate image from the intermediate image. And a second imaging optical system for forming a final image on the second surface based on the light beam. In this case, the first imaging optical system includes a first lens group having a positive refractive power, a first reflecting mirror disposed in an optical path between the first lens group and the intermediate image, It is preferable that a second reflecting mirror disposed in an optical path between the first reflecting mirror and the intermediate image is provided.

  In this case, the first reflecting mirror is a concave reflecting mirror disposed in the vicinity of the pupil plane of the first imaging optical system, and at least one negative reflecting path is formed in the reciprocating optical path formed by the concave reflecting mirror. It is preferable that a lens is disposed. Furthermore, in this case, it is preferable that the at least one negative lens and the boundary lens arranged in the reciprocating optical path are made of fluorite.

  Further, according to a preferred aspect of the first embodiment, when the focal length of the first lens group is F1 and the maximum image height on the second surface is Y0, the condition of 5 <F1 / Y0 <15 is satisfied. To do. The first lens group preferably includes at least two positive lenses. In addition, it is preferable that the second imaging optical system is a refractive optical system that includes only a plurality of transmission members. In this case, it is preferable that 70% or more of the transmissive members constituting the second imaging optical system are made of quartz.

  According to a preferred aspect of the first aspect, the effective imaging region has an arc shape, the radius of curvature of the arc defining the effective imaging region is R, and the maximum on the second surface is When the image height is Y0, the condition of 1.05 <R / Y0 <12 is satisfied.

In the second embodiment of the present invention, in a catadioptric projection optical system that forms a reduced image of the first surface on the second surface,
An effective imaging region having an arc shape that includes at least two reflecting mirrors and a transmitting member, and does not include the optical axis of the projection optical system;
When the radius of curvature of the arc that defines the effective imaging region is R, and the maximum image height on the second surface is Y0,
1.05 <R / Y0 <12
A projection optical system characterized by satisfying the above conditions is provided.

  In the third aspect of the present invention, an illumination system for illuminating the mask set on the first surface and an image of a pattern formed on the mask are formed on the photosensitive substrate set on the second surface. There is provided an exposure apparatus comprising the projection optical system of the first form or the second form.

According to a preferred aspect of the third aspect, the mask and the photosensitive substrate are moved relative to the projection optical system along a predetermined direction to project and expose the mask pattern onto the photosensitive substrate.

  In the fourth embodiment of the present invention, the mask set on the first surface is illuminated, and the pattern formed on the mask via the projection optical system of the first or second embodiment is set on the second surface. There is provided an exposure method characterized by performing projection exposure on a photosensitive substrate.

  The projection optical system of the present invention includes at least two reflecting mirrors and a boundary lens having a positive refractive power on the first surface side, and all the transmitting members and reflecting members are arranged along a single optical axis. In the configuration having an effective imaging region that does not include the optical axis, the optical path between the boundary lens and the second surface is filled with a medium having a refractive index larger than 1.1. As a result, in the present invention, various aberrations such as chromatic aberration and curvature of field are satisfactorily corrected to have excellent imaging performance, and a large effective image-side numerical aperture with excellent reflection loss on the optical surface. It is possible to realize a relatively small projection optical system capable of ensuring the above.

  Therefore, in the exposure apparatus and exposure method using the projection optical system of the present invention, a fine pattern can be formed through the projection optical system having excellent imaging performance and a large effective image-side numerical aperture and thus high resolution. Transfer exposure can be performed with high accuracy. In addition, a good microdevice can be manufactured by high-precision projection exposure through a high-resolution projection optical system using an exposure apparatus equipped with the projection optical system of the present invention.

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 arc-shaped effective exposure area | region formed on a wafer in this embodiment, and an optical axis. It is a figure which shows schematically the structure between the boundary lens and wafer in 1st Example of this embodiment. It is a figure which shows schematically the structure between the boundary lens and wafer in 2nd 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 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 2nd Example. 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.

In the projection optical system of the present invention, an image-side numerical aperture NA is increased by interposing a medium having a refractive index larger than 1.1 in the optical path between the boundary lens and the image surface (second surface). I am trying. By the way, “Resolution Enhancement of 157-nm Lithography by Liquid Immersion” announced by M.Switkes and M.Rothschild at “Massachusetts Institute of Technology” at “SPIE2002 Microlithography” is required for light with a wavelength λ of 200 nm or less. Fluorinert (Perfluoropolyethers: trade name of 3M USA), deionized water, and the like are listed as candidates for a medium having such transmittance.

Further, in the projection optical system of the present invention, by imparting a positive refractive power to the object side (first surface side) optical surface of the boundary lens, the reflection loss on this optical surface is reduced, and as a result, it is highly effective. A large image-side numerical aperture can be ensured. As described above, in an optical system having a high refractive index substance such as a liquid as a medium on the image side, the effective image-side numerical aperture can be increased to 1.0 or more, and the resolution can be increased. However, when the projection magnification is constant, the object-side numerical aperture increases with an increase in the image-side numerical aperture. Therefore, if the projection optical system is configured with only a refractive member, it is difficult to satisfy the Petzval condition. Larger size is inevitable.

  Therefore, the projection optical system of the present invention includes at least two reflecting mirrors, all the transmitting members and all the reflecting members having refractive power (power) are arranged along a single optical axis, and include the optical axis. A catadioptric optical system of a type having an effective imaging area of a predetermined shape is employed. In this type of projection optical system, for example, the chromatic aberration can be corrected satisfactorily by the action of a concave reflecting mirror, the Petzval condition can be easily satisfied and the field curvature can be corrected well, and the optical system can be downsized. Is possible.

  Further, in this type of projection optical system, all the transmissive members (such as lenses) and all the reflecting members having power (such as concave reflecting mirrors) are arranged along a single optical axis. Compared with the multi-axis configuration respectively disposed along the optical axis, the manufacturing difficulty is remarkably lowered, which is preferable. However, in the case of a single-axis configuration in which the optical member is arranged along a single optical axis, it tends to be difficult to correct chromatic aberration well. For example, the spectral width is narrowed like ArF laser light. This problem of chromatic aberration correction can be overcome by using the laser beam.

  In this way, in the present invention, various aberrations such as chromatic aberration and curvature of field are corrected satisfactorily, and the imaging performance is excellent, and the reflection loss on the optical surface is suppressed satisfactorily and a large effective image-side numerical aperture is increased. A relatively small projection optical system that can be secured can be realized. Therefore, in the exposure apparatus and exposure method using the projection optical system of the present invention, a fine pattern can be formed through the projection optical system having excellent imaging performance and a large effective image-side numerical aperture and thus high resolution. Transfer exposure can be performed with high accuracy.

  In the present invention, the projection optical system is configured to have an even number of reflecting mirrors, that is, the image of the first surface is formed on the second surface through an even number of reflections. preferable. With this configuration, when applied to, for example, an exposure apparatus or an exposure method, a surface image (an upright image or an inverted image) is formed on the wafer instead of the back image of the mask pattern. A normal mask (reticle) can be used in the same manner as the exposure apparatus to be mounted.

  By the way, in order to construct the catadioptric projection optical system of the present invention with a single optical axis, it is necessary to form an intermediate image in the vicinity of the pupil position. Therefore, the projection optical system is preferably a re-imaging optical system. . In order to avoid the mechanical interference between optical members while forming an intermediate image near the pupil position of the first image formation and performing optical path separation, the pupil of the first image formation is used even when the object-side numerical aperture is increased. Since it is necessary to make the diameter as small as possible, it is desirable that the first imaging optical system having a small numerical aperture is a catadioptric optical system.

  Therefore, in the present invention, the first image forming optical system for forming an intermediate image of the first surface including at least two reflecting mirrors and the final image is formed on the second surface based on the light flux from the intermediate image. It is preferable that the projection optical system is constituted by the second imaging optical system for this purpose. In this case, specifically, a first lens group having positive refractive power, a first reflecting mirror disposed in an optical path between the first lens group and the intermediate image, and the first reflecting mirror and the intermediate image. The first imaging optical system can be configured using the second reflecting mirror disposed in the optical path between the first and the second reflecting mirrors.

The first reflecting mirror is a concave reflecting mirror disposed in the vicinity of the pupil plane of the first imaging optical system, and at least one negative lens is disposed in a round-trip optical path formed by the concave reflecting mirror. Preferably it is. In this way, by disposing the negative lens in the reciprocating optical path formed by the concave reflecting mirror in the first imaging optical system, it becomes possible to satisfactorily satisfy the Petzval condition and correct the field curvature well. At the same time, chromatic aberration can be corrected well.

  In addition, it is desirable that the negative lens in the reciprocating optical path is disposed in the vicinity of the pupil position. However, since the pupil diameter of the first imaging needs to be made as small as possible, the effective diameter of the negative lens is also reduced. The fluence (= unit area / energy amount per unit pulse) tends to be high. Therefore, when the negative lens is formed using quartz, a local refractive index change due to volume contraction, that is, compaction is likely to occur due to the irradiation of the laser beam, and the imaging performance of the projection optical system is lowered.

  Similarly, the boundary lens arranged close to the image plane also has a small effective diameter and tends to have a high fluence. Therefore, when the boundary lens is formed using quartz, compaction is likely to occur, and the imaging performance is deteriorated. In the present invention, the negative lens arranged in the reciprocating optical path formed by the concave reflecting mirror in the first imaging optical system and the boundary lens arranged in the vicinity of the image plane in the second imaging optical system are made of fluorite. By forming, it is possible to avoid a reduction in imaging performance due to compaction.

In the present invention, it is preferable that the following conditional expression (1) is satisfied. In conditional expression (1), F1 is the focal length of the first lens group, and Y0 is the maximum image height on the second surface.
5 <F1 / Y0 <15 (1)

  Exceeding the upper limit of conditional expression (1) is not preferable because the pupil diameter of the first image formation becomes too large and it becomes difficult to avoid mechanical interference between optical members as described above. On the other hand, if the lower limit value of conditional expression (1) is not reached, a difference (angle of view angle) due to the object height of the angle of light incident on the reflecting mirror is greatly generated, and it is difficult to correct coma and aberrations such as field curvature. This is not preferable. In order to achieve the effect of the present invention more satisfactorily, it is more preferable to set the upper limit value of conditional expression (1) to 13 and the lower limit value to 7.

  In the present invention, it is preferable that the first lens group has at least two positive lenses. With this configuration, the positive refracting power of the first lens group can be set to be large and conditional expression (1) can be easily satisfied, and coma, distortion, astigmatism, etc. can be corrected well. .

  In addition, it is difficult to manufacture a reflecting mirror having high reflectivity and high durability, and providing a large number of reflecting surfaces leads to light loss. Therefore, in the present invention, for example, when the projection optical system is applied to an exposure apparatus or an exposure method, the second imaging optical system is a refractive optical system composed of only a plurality of transmission members from the viewpoint of improving the throughput. Is preferred.

  In addition, fluorite is a crystalline material having intrinsic birefringence, and a transmission member made of fluorite has a large influence of birefringence on light having a wavelength of 200 nm or less. For this reason, in an optical system including a fluorite transmissive member, it is necessary to combine a fluorite transmissive member having a different crystal axis orientation to suppress a decrease in imaging performance due to birefringence. The performance degradation due to refraction cannot be completely suppressed.

Furthermore, 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 tend to cause flare and easily deteriorate the imaging performance of the projection optical system. It is preferable to reduce the use of fluorite as much as possible. Therefore, in the present invention, in order to reduce the use of fluorite as much as possible, 70% or more of the transmissive members constituting the second imaging optical system, which is a refractive optical system, are formed of quartz. It is preferable.

In the present invention, it is desirable that the effective imaging region has an arc shape and satisfies the following conditional expression (2). In conditional expression (2), R is the size of the radius of curvature of the arc that defines the effective imaging region, and Y0 is the maximum image height on the second surface as described above.
1.05 <R / Y0 <12 (2)

  In the present invention, by having an arc-shaped effective imaging region that does not include the optical axis, it is possible to easily perform optical path separation while avoiding an increase in the size of the optical system. However, for example, when applied to an exposure apparatus or an exposure method, it is difficult to uniformly illuminate the arc-shaped illumination area on the mask. Therefore, a technique is adopted in which a rectangular illumination light beam corresponding to a rectangular area including an arc-shaped area is limited by a field stop having an arc-shaped opening (light transmission part). In this case, in order to suppress the light amount loss at the field stop, it is necessary that the radius R of the radius of curvature of the arc that defines the effective imaging region is as large as possible.

  That is, if the lower limit value of the conditional expression (2) is not reached, the radius R of the curvature radius becomes too small, the luminous flux loss at the field stop becomes large, and this decreases the illumination efficiency, which is not preferable. On the other hand, when the upper limit value of conditional expression (2) is exceeded, the radius R of the curvature radius becomes too large, and an effective imaging region having a required width is to be secured in order to shorten the overrun length during scanning exposure. Then, since a necessary aberration correction area becomes large, the optical system becomes large, which is not preferable. In order to achieve the effect of the present invention more satisfactorily, it is more preferable to set the upper limit value of conditional expression (2) to 8 and the lower limit value to 1.07.

  In the catadioptric projection optical system of the type described above, conditional expression (2) should be satisfied even when the optical path between the image plane (second surface) is not filled with a medium such as a liquid. Accordingly, it is possible to avoid a decrease in throughput due to a decrease in illumination efficiency and an increase in the size of the optical system due to an increase in a necessary aberration correction region. Further, when the projection optical system of the present invention is applied to an exposure apparatus or an exposure method, the transmittance of a medium (liquid etc.) filled between the boundary lens and the image plane, the degree of narrowing of the laser beam, etc. In consideration, for example, it is preferable to use ArF laser light (wavelength 193.306 nm) as exposure light.

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 Z axis is parallel to the optical axis AX of the projection optical system PL, the Y axis is parallel to the paper surface of FIG. 1 in the plane perpendicular to the optical axis AX, and the X axis is perpendicular to the paper surface of FIG. Are set respectively.

  The illustrated exposure apparatus includes an ArF excimer laser light source as the light source 100 for supplying illumination light in the ultraviolet region. The light emitted from the light source 100 illuminates the reticle R on which a predetermined pattern is formed in a superimposed manner via the illumination optical system IL. The optical path between the light source 100 and the illumination optical system IL is sealed with a casing (not shown), and the space from the light source 100 to the optical member on the most reticle side in the illumination optical system IL absorbs exposure light. It is replaced with an inert gas such as helium gas or nitrogen, which is a low-rate gas, or is kept in a substantially vacuum state.

The reticle R is held parallel to the XY plane on the reticle stage RS via the reticle holder RH. A pattern to be transferred is formed on the reticle R, and an arc-shaped pattern region extending in the X direction without including the optical axis AX is illuminated. Reticle stage RS can be moved two-dimensionally along the reticle plane (ie, XY plane) by the action of a drive system (not shown), and its position coordinates are measured by interferometer RIF using reticle moving mirror RM. And the position is controlled. Light from the pattern formed on the reticle R forms a reticle pattern image on the wafer W, which is a photosensitive substrate, via the projection optical system PL.

  The wafer W is held parallel to the XY plane on the wafer stage WS via the wafer holder table WT. Further, an arc-shaped still exposure region (that is, effective exposure region: projection) extending in the X direction without including the optical axis AX also on the wafer W so as to optically correspond to the arc-shaped illumination region on the reticle R. A pattern image is formed in an effective imaging region) of the optical system PL. The wafer stage WS can be moved two-dimensionally along the wafer surface (that is, the XY plane) by the action of a drive system (not shown), and its position coordinates are measured by an interferometer WIF using a wafer moving mirror WM. In addition, the position is controlled.

  FIG. 2 is a view showing the positional relationship between the arc-shaped effective exposure region formed on the wafer and the optical axis in the present embodiment. In the present embodiment, as shown in FIG. 2, the region in which the aberration is favorably corrected, that is, the aberration correction region AR has a circle having an outer diameter (radius) Ro and an inner diameter (radius) Ri centered on the optical axis AX. An arc shape is defined by a circle and two line segments parallel to the Y direction that are separated by a distance H. The effective exposure region (effective image formation region) ER has a radius of curvature R of two arcs spaced in the Y direction and a distance H so as to be substantially inscribed in the arc-shaped aberration correction region AR. An arc shape is defined by two line segments having a length D parallel to the Y direction and spaced apart from each other.

  Thus, all effective imaging regions ER of the projection optical system PL exist in regions outside the optical axis AX. The dimension along the X direction of the arc-shaped effective exposure region ER is H, and the dimension along the Y direction is D. Therefore, although not shown, an arc-shaped illumination area (that is, an effective illumination area) having a size and shape optically corresponding to the arc-shaped effective exposure area ER is provided on the reticle R with the optical axis AX. It is formed without including.

  In the exposure apparatus of the present embodiment, the optical member (lens L11 in each example) and the boundary lens Lb (lens L217 in each example) arranged on the most reticle side among the optical members constituting the projection optical system PL. The interior of the projection optical system PL is kept in an airtight state, and the gas inside the projection optical system PL is replaced with an inert gas such as helium gas or nitrogen, or is kept in a substantially vacuum state. Has been. Further, a reticle R and a reticle stage RS are arranged in a narrow optical path between the illumination optical system IL and the projection optical system PL, but a casing (not shown) that hermetically surrounds the reticle R and the reticle stage RS. Is filled with an inert gas such as nitrogen or helium gas, or is kept in a vacuum state.

  FIG. 3 is a diagram schematically showing a configuration between the boundary lens and the wafer in the first example of the present embodiment. Referring to FIG. 3, in the first example, the boundary lens Lb has a convex surface toward the reticle side (first surface side). In other words, the reticle-side surface Sb of the boundary lens Lb has a positive refractive power. The optical path between the boundary lens Lb and the wafer W is filled with a medium Lm having a refractive index larger than 1.1. In the first embodiment, deionized water is used as the medium Lm.

FIG. 4 is a diagram schematically showing a configuration between the boundary lens and the wafer in the second example of the present embodiment. Referring to FIG. 4, in the second embodiment, as in the first embodiment, the boundary lens Lb has a convex surface toward the reticle side, and the reticle-side surface Sb has a positive refractive power. However, in the second embodiment, unlike the first embodiment, a parallel plane plate Lp is detachably disposed in the optical path between the boundary lens Lb and the wafer W, and the boundary lens Lb and the parallel plane plate Lp are arranged. And the optical path between the plane parallel plate Lp and the wafer W are filled with a medium Lm having a refractive index greater than 1.1. In the second embodiment, as in the first embodiment, deionized water is used as the medium Lm.

  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 For example, the technique disclosed in International Publication No. WO99 / 49504 or the technique disclosed in Japanese Patent Laid-Open No. 10-303114 can be used to keep the liquid medium Lm in the optical path between the two.

  In the technique disclosed in International Publication No. WO99 / 49504, the liquid (medium Lm) adjusted to a predetermined temperature is supplied between the boundary lens Lb and the wafer W through the supply pipe and the discharge nozzle from the liquid supply device. The liquid is supplied so as to fill the optical path, and the liquid is recovered from the wafer W via the recovery pipe and the inflow nozzle by the liquid supply device. The liquid supply amount and the recovery amount are adjusted according to the relative movement speed of the wafer W with respect to the projection optical system PL.

  On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 10-303114, the wafer holder table WT is configured in a container shape so as to accommodate the liquid (medium Lm), and at the center of its inner bottom (in the liquid ) The wafer W is positioned and held by vacuum 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.

  Thus, an atmosphere in which exposure light is hardly absorbed is formed over the entire optical path from the light source 100 to the wafer W. Further, as described above, the illumination area on the reticle R and the exposure area on the wafer W (that is, the effective exposure area ER) have an arc shape extending in the X direction. Accordingly, the reticle stage RS and the wafer stage WS are moved along the Y direction while the position of the reticle R and the wafer W is controlled using a drive system and an interferometer (RIF, WIF). Are moved (scanned) synchronously to expose the wafer W having a width equal to the dimension H in the X direction of the effective exposure region ER and a length corresponding to the scanning amount (moving amount) of the wafer W. A reticle pattern is scanned and exposed to the area.

In each embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangential plane at the apex of the aspheric surface to the position on the aspheric surface at height y. ) Is z, the apex radius of curvature is r, the conic coefficient is κ, and the nth-order aspheric coefficient is Cn, it is expressed by the following formula (a). In each embodiment, the lens surface formed in an aspherical shape is marked with * 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 embodiment, the projection optical system PL includes a first imaging optical system G1 for forming an intermediate image of the pattern of the reticle R disposed on the object surface (first surface), and light from the intermediate image. And a second imaging optical system G2 for forming a reduced image of the reticle pattern on the wafer W arranged on the image surface (second surface). Here, the first imaging optical system G1 is a catadioptric optical system including a first concave reflecting mirror CM1 and a second concave reflecting mirror CM2, and the second imaging optical system G2 is a refractive optical system.

(First embodiment)
FIG. 5 is a diagram showing a lens configuration of the projection optical system according to the first example of the present embodiment. Referring to FIG. 5, in the projection optical system PL according to the first example, the first imaging optical system G1 has aspherical convex surfaces directed toward the wafer side in order from the reticle side along the light traveling direction. A biconvex lens L11, a biconvex lens L12, a negative meniscus lens L13 having an aspheric concave surface facing the reticle side, and a first concave reflecting mirror CM1 are provided. In the first imaging optical system G1, the second concave reflecting mirror CM2 for reflecting the light reflected by the first concave reflecting mirror CM1 and passing through the negative meniscus lens L13 toward the second imaging optical system G2. Is disposed in a region not including the optical axis AX between the biconvex lens L12 and the negative meniscus lens L13. Therefore, the biconvex lens L11 and the biconvex lens L12 constitute a first lens group having a positive refractive power. Further, the first concave reflecting mirror CM1 constitutes a concave reflecting mirror disposed in the vicinity of the pupil plane of the first imaging optical system G1.

  On the other hand, the second imaging optical system G2 has, in order from the reticle side along the light traveling direction, a positive meniscus lens L21 having a concave surface facing the reticle side, a biconvex lens L22, and an aspheric concave surface on the wafer side. Both a positive meniscus lens L23 directed to the surface, a negative meniscus lens L24 having an aspherical convex surface facing the reticle side, a negative meniscus lens L25 having a convex surface facing the reticle side, and an aspherical concave surface facing the reticle side. Concave lens L26, positive meniscus lens L27 having a concave surface facing the reticle, negative meniscus lens L28 having an aspheric convex surface facing the reticle, biconvex lens L29, biconvex lens L210, and convex surface facing the reticle Positive meniscus lens L211, aperture stop AS, positive meniscus lens L212 having a concave surface facing the reticle, and biconvex lens 213, a positive meniscus lens L214 having an aspheric concave surface facing the wafer, a positive meniscus lens L215 having a convex surface facing the reticle, a positive meniscus lens L216 having an aspheric concave surface facing the wafer, and the wafer And a plano-convex lens L217 (boundary lens Lb) having a flat surface facing the side.

  In the first embodiment, all the transmitting members (lenses) constituting the projection optical system PL and all the reflecting members having power (the first concave reflecting mirror CM1 and the second concave reflecting mirror CM2) have a single optical axis AX. Are arranged along. That is, 100% of the transmissive members constituting the second imaging optical system G2 are made of quartz. The optical path between the plano-convex lens L217 as the boundary lens Lb and the wafer W is filled with a medium Lm made of deionized water. In the first embodiment, the light from the reticle R enters the first concave reflecting mirror CM1 through the lenses L11 to L13. The light reflected by the first concave reflecting mirror CM1 forms an intermediate image of the reticle R in the vicinity of the first concave reflecting mirror CM1 via the lens L13 and the second concave reflecting mirror CM2. The light reflected by the second concave reflecting mirror CM2 forms a reduced image of the reticle R on the wafer W via the lenses L21 to L217 (Lb).

In the first example, all the transmissive members (lenses) constituting the projection optical system PL are made of quartz (SiO ₂ ). The oscillation center wavelength of ArF excimer laser light as exposure light is 193.306 nm, and the refractive index of quartz changes at a rate of −1.591 × 10 ⁻⁶ per +1 pm wavelength change in the vicinity of 193.306 nm, It changes at a rate of + 1.591 × 10 ⁻⁶ per wavelength change of −1 pm. In other words, in the vicinity of 193.306 nm, the refractive index dispersion (dn / dλ) of quartz is −1.591 × 10 ⁻⁶ / pm. In addition, the refractive index of deionized water near 193.306 nm changes at a rate of −2.6 × 10 ⁻⁶ per +1 pm wavelength change, and at a rate of + 2.6 × 10 ⁻⁶ per −1 pm wavelength change. Change. In other words, in the vicinity of 193.306 nm, the refractive index dispersion (dn / dλ) of deionized water is −2.6 × 10 ⁻⁶ / pm.

  Thus, in the first example, the refractive index of quartz with respect to the center wavelength of 193.306 nm is 1.5603261, and the refractive index of quartz with respect to 193.306 nm + 0.1 pm = 193.3061 nm is 1.560362591, and 193.306 nm− The refractive index of quartz for 0.1 pm = 193.3059 nm is 1.560332659. Further, the refractive index of deionized water with respect to the central wavelength of 193.306 nm is 1.47, the refractive index of deionized water with respect to 193.306 nm + 0.1 pm = 193.3061 nm is 1.46999974, and 193.306 nm-0. The refractive index of deionized water for 1 pm = 193.3059 nm is 1.47000026.

  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 Ro and Ri are the aberration correction area AR. The outer radius and the inner radius, H and D are the X-direction and Y-direction dimensions of the effective exposure region ER, and R is the radius of curvature of the arc that defines the arc-shaped effective exposure region ER (effective imaging region). Y0 represents the maximum image height. The surface number is the order of the surfaces from the reticle side along the direction in which the light beam travels from the reticle surface, which is the object surface (first surface), to the wafer surface, which 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 first concave reflecting mirror CM1 to the second concave reflecting mirror CM2, and positive in the other optical paths. Regardless of the incident direction of light, the curvature radius of the convex surface toward the reticle side is positive, and the curvature radius of the concave surface 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 = 1.04
Ro = 17.0mm
Ri = 11.5mm
H = 26.0mm
D = 4.0mm
R = 20.86mm
Y0 = 17.0mm

(Optical member specifications)
Surface number r dn Optical member (reticle surface) 70.25543
1 444.28100 45.45677 1.5603261 (L11)
2 * -192.24078 1.00000
3 471.20391 35.53423 1.5603261 (L12)
4 -254.24538 122.19951
5 * -159.65514 13.00000 1.5603261 (L13)
6 -562.86259 9.00564
7 -206.23868 -9.00564 (CM1)
8 -562.86259 -13.00000 1.5603261 (L13)
9 * -159.65514 -107.19951
10 3162.83419 144.20515 (CM2)
11 -389.01215 43.15699 1.5603261 (L21)
12 -198.92113 1.00000
13 3915.27567 42.01089 1.5603261 (L22)
14 -432.52137 1.00000
15 203.16777 62.58039 1.5603261 (L23)
16 * 515.92133 18.52516
17 * 356.67027 20.00000 1.5603261 (L24)
18 269.51733 285.26014
19 665.61079 35.16606 1.5603261 (L25)
20 240.55938 32.43496
21 * -307.83344 15.00000 1.5603261 (L26)
22 258.17867 58.24284
23 -1143.34122 51.43638 1.5603261 (L27)
24 -236.25969 6.67292
25 * 1067.55487 15.00000 1.5603261 (L28)
26 504.02619 18.88857
27 4056.97655 54.00381 1.5603261 (L29)
28 -283.04360 1.00000
29 772.31002 28.96307 1.5603261 (L210)
30 -8599.87899 1.00000
31 667.92225 52.94747 1.5603261 (L211)
32 36408.68946 2.30202
33 ∞ 42.27703 (AS)
34 -2053.34123 30.00000 1.5603261 (L212)
35 -514.67146 1.00000
36 1530.45141 39.99974 1.5603261 (L213)
37 -540.23726 1.00000
38 370.56341 36.15464 1.5603261 (L214)
39 * 12719.40982 1.00000
40 118.92655 41.83608 1.5603261 (L215)
41 190.40194 1.00000
42 151.52892 52.42553 1.5603261 (L216)
43 * 108.67474 1.12668
44 91.54078 35.50067 1.5603261 (L217: Lb)
45 ∞ 6.00000 1.47 (Lm)
(Wafer surface)

(Aspheric data)
2 sides κ = 0
C4 = −8.63025 × 10 ⁻⁹ C6 = 2.90424 × 10 ⁻¹³
C8 = 5.443348 × 10 ⁻¹⁷ C10 = 1.65523 × 10 ⁻²¹
C12 = 8.778237 × 10 ⁻²⁶ C14 = 6.553360 × 10 ⁻³⁰

5 and 9 (same surface)
κ = 0
C4 = 7.666590 × 10 ⁻⁹ C6 = 6.09920 × 10 ⁻¹³
C8 = −6.53660 × 10 ⁻¹⁷ C10 = 2.44925 × 10 ⁻²⁰
C12 = −3.14967 × 10 ⁻²⁴ C14 = 2.16772 × 10 ⁻²⁸

16 faces κ = 0
C4 = -3.79715 × 10 ⁻⁸ C6 = 2.19518 × 10 ⁻¹²
C8 = −9.4364 × 10 ⁻¹⁷ C10 = 3.333573 × 10 ⁻²¹
C12 = −7.442012 × 10 ⁻²⁶ C14 = 1.05652 × 10 ⁻³⁰

17 faces κ = 0
C4 = −6.66956 × 10 ⁻⁸ C6 = 1.75761 × 10 ⁻¹²
C8 = −6.18763 × 10 ⁻¹⁷ C10 = 2.65428 × 10 ⁻²¹
C12 = −4.095555 × 10 ⁻²⁶ C14 = 3.25841 × 10 ⁻³¹

21 surface κ = 0
C4 = −8.68772 × 10 ⁻⁸ C6 = −1.30306 × 10 ⁻¹²
C8 = −2.665902 × 10 ⁻¹⁷ C10 = −6.556830 × 10 ⁻²¹
C12 = 3.669980 × 10 ⁻²⁵ C14 = −5.05555 × 10 ⁻²⁹

25 faces κ = 0
C4 = -1.54049 × 10 ⁻⁸ C6 = 7.71505 × 10 ⁻¹⁴
C8 = 1.75760 × 10 ⁻¹⁸ C10 = 1.713383 × 10 ⁻²³
C12 = 5.04584 × 10 ⁻²⁹ C14 = 2.86622 × 10 ⁻³²

39 surfaces κ = 0
C4 = −3.91974 × 10 ⁻¹¹ C6 = 5.99062 × 10 ⁻¹⁴
C8 = 2.85949 × 10 ⁻¹⁸ C10 = −1.01828 × 10 ⁻²²
C12 = 2.26543 × 10 ⁻²⁷ C14 = −1.906645 × 10 ⁻³²

43 planes κ = 0
C4 = 8.333324 × 10 ⁻⁸ C6 = 1.42277 × 10 ⁻¹¹
C8 = −1.13452 × 10 ⁻¹⁵ C10 = 1.18459 × 10 ⁻¹⁸
C12 = −2.83937 × 10 ⁻²² C14 = 5.01735 × 10 ⁻²⁶

(Values for conditional expressions)
F1 = 164.15mm
Y0 = 17.0mm
R = 20.86mm
(1) F1 / Y0 = 9.66
(2) R / Y0 = 1.227

  FIG. 6 is a diagram showing transverse aberration in the first example. In the aberration diagrams, Y indicates the image height, the solid line indicates the center wavelength of 193.3060 nm, the broken line indicates 193.306 nm + 0.1 pm = 193.3061 nm, and the alternate long and short dash line indicates 193.306 nm−0.1 pm = 193.3059 nm. Yes. The notation in FIG. 6 is the same in FIG. 8 below. As is apparent from the aberration diagram of FIG. 6, in the first example, although a very large image-side numerical aperture (NA = 1.04) and a relatively large effective exposure area ER are secured, the wavelength It can be seen that chromatic aberration is well corrected for exposure light having a width of 193.306 nm ± 0.1 pm.

(Second embodiment)
FIG. 7 is a diagram showing a lens configuration of the projection optical system according to the second example of the present embodiment. Referring to FIG. 7, in the projection optical system PL according to the second example, the first imaging optical system G1 has the aspherical convex surface directed toward the wafer side in order from the reticle side along the light traveling direction. A biconvex lens L11, a biconvex lens L12, a negative meniscus lens L13 having an aspheric concave surface facing the reticle side, and a first concave reflecting mirror CM1 are provided. In the first imaging optical system G1, the second concave reflecting mirror CM2 for reflecting the light reflected by the first concave reflecting mirror CM1 and passing through the negative meniscus lens L13 toward the second imaging optical system G2. Is disposed in a region not including the optical axis AX between the biconvex lens L12 and the negative meniscus lens L13. Therefore, the biconvex lens L11 and the biconvex lens L12 constitute a first lens group having a positive refractive power. Further, the first concave reflecting mirror CM1 constitutes a concave reflecting mirror disposed in the vicinity of the pupil plane of the first imaging optical system G1.

  On the other hand, the second imaging optical system G2 has, in order from the reticle side along the light traveling direction, a positive meniscus lens L21 having a concave surface facing the reticle side, a biconvex lens L22, and an aspheric concave surface on the wafer side. Both a positive meniscus lens L23 directed to the surface, a negative meniscus lens L24 having an aspherical convex surface facing the reticle side, a negative meniscus lens L25 having a convex surface facing the reticle side, and an aspherical concave surface facing the reticle side. Concave lens L26, positive meniscus lens L27 having a concave surface facing the reticle, negative meniscus lens L28 having an aspheric convex surface facing the reticle, biconvex lens L29, biconvex lens L210, and convex surface facing the reticle Positive meniscus lens L211, aperture stop AS, positive meniscus lens L212 having a concave surface facing the reticle, and biconvex lens 213, a positive meniscus lens L214 having an aspheric concave surface facing the wafer, a positive meniscus lens L215 having a convex surface facing the reticle, a positive meniscus lens L216 having an aspheric concave surface facing the wafer, and the wafer And a plano-convex lens L217 (boundary lens Lb) having a flat surface facing the side.

In the second embodiment, a parallel plane plate Lp is disposed in the optical path between the plano-convex lens L217 as the boundary lens Lb and the wafer W. The optical path between the boundary lens Lb and the plane parallel plate Lp and the optical path between the plane parallel plate Lp and the wafer W are filled with a medium Lm made of deionized water. In the second embodiment, the transmitting member (lens) constituting the projection optical system PL is made of quartz or fluorite (CaF2). Specifically, the lens L13
The lens L216 and the lens L217 (Lb) are made of fluorite, and the other lenses and the plane parallel plate Lp are made of quartz. That is, about 88% of the transmissive members constituting the second imaging optical system G2 are made of quartz.

  Furthermore, in the second embodiment, all the transmissive members (lenses, parallel plane plates) and all the reflective members (first concave reflector CM1, second concave reflector CM2) having power are included in the projection optical system PL. Arranged along a single optical axis AX. Thus, in the second embodiment, the light from the reticle R enters the first concave reflecting mirror CM1 via the lenses L11 to L13. The light reflected by the first concave reflecting mirror CM1 forms an intermediate image of the reticle R in the vicinity of the first concave reflecting mirror CM1 via the lens L13 and the second concave reflecting mirror CM2. The light reflected by the second concave reflecting mirror CM2 forms a reduced image of the reticle R on the wafer W via the lenses L21 to L217 (Lb) and the parallel flat plate Lp.

In the second embodiment, the oscillation center wavelength of the ArF excimer laser light that is the exposure light is 193.306 nm, and the refractive index of quartz is about −1.591 × 10 ⁻⁶ per wavelength change of +1 pm near 193.306 nm. At a rate of + 1.591 × 10 ⁻⁶ per wavelength change of −1 pm. In other words, in the vicinity of 193.306 nm, the refractive index dispersion (dn / dλ) of quartz is −1.591 × 10 ⁻⁶ / pm. In addition, the refractive index of fluorite changes around 193.306 nm at a rate of −0.980 × 10 ⁻⁶ per +1 pm wavelength change and changes at a rate of + 0.980 × 10 ⁻⁶ per −1 pm wavelength change. To do. In other words, the refractive index dispersion (dn / dλ) of fluorite is −0.980 × 10 ⁻⁶ / pm in the vicinity of 193.306 nm.

Further, near 193.306 nm, the refractive index of deionized water changes at a rate of −2.6 × 10 ⁻⁶ per +1 pm wavelength change, and at a rate of + 2.6 × 10 ⁻⁶ per −1 pm wavelength change. Change. In other words, in the vicinity of 193.306 nm, the refractive index dispersion (dn / dλ) of deionized water is −2.6 × 10 ⁻⁶ / pm. Thus, in the second embodiment, the refractive index of quartz with respect to the center wavelength of 193.306 nm is 1.5603261, and the refractive index of quartz with respect to 193.306 nm + 0.1 pm = 193.3061 nm is 1.560325941, and 193.306 nm− The refractive index of quartz for 0.1 pm = 193.3059 nm is 1.560332659.

  The refractive index of fluorite with respect to the center wavelength of 193.306 nm is 1.5014548, the refractive index of fluorite with respect to 193.306 nm + 0.1 pm = 193.3061 nm is 1.501445402, and 193.306 nm−0.1 pm = The refractive index of fluorite for 193.3059 nm is 1.5014454898. Further, the refractive index of deionized water with respect to the center wavelength of 193.306 nm is 1.47, the refractive index of deionized water with respect to 193.306 nm + 0.1 pm = 193.3061 nm is 1.46999974, and 193.306 nm−0.3. The refractive index of deionized water for 1 pm = 193.3059 nm is 1.47000026. 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 = 1.04
Ro = 17.0mm
Ri = 11.5mm
H = 26.0mm
D = 4.0mm
R = 20.86mm
Y0 = 17.0mm

(Optical member specifications)
Surface number r dn Optical member (reticle surface) 72.14497
1 295.66131 46.03088 1.5603261 (L11)
2 * -228.07826 1.02581
3 847.63618 40.34103 1.5603261 (L12)
4 -207.90948 124.65407
5 * -154.57886 13.00000 1.5014548 (L13)
6 -667.19164 9.58580
7 -209.52775 -9.58580 (CM1)
8 -667.19164 -13.00000 1.5014548 (L13)
9 * -154.57886 -109.65407
10 2517.52751 147.23986 (CM2)
11 -357.71318 41.75496 1.5603261 (L21)
12 -196.81705 1.00000
13 8379.53651 40.00000 1.5603261 (L22)
14 -454.81020 8.23083
15 206.30063 58.07852 1.5603261 (L23)
16 * 367.14898 24.95516
17 * 258.66863 20.00000 1.5603261 (L24)
18 272.27694 274.16477
19 671.42370 49.62123 1.5603261 (L25)
20 225.79907 35.51978
21 * -283.63484 15.10751 1.5603261 (L26)
22 261.37852 56.71822
23 -1947.68869 54.63076 1.5603261 (L27)
24 -227.05849 5.77639
25 * 788.97953 15.54026 1.5603261 (L28)
26 460.12935 18.83954
27 1925.75038 56.54051 1.5603261 (L29)
28 -295.06884 1.00000
29 861.21046 52.50515 1.5603261 (L210)
30 -34592.86759 1.00000
31 614.86639 37.34179 1.5603261 (L211)
32 39181.66426 1.00000
33 ∞ 46.27520 (AS)
34 -11881.91854 30.00000 1.5603261 (L212)
35 -631.95129 1.00000
36 1465.88641 39.89113 1.5603261 (L213)
37 -542.10144 1.00000
38 336.45791 34.80369 1.5603261 (L214)
39 * 2692.15238 1.00000
40 112.42843 43.53915 1.5603261 (L215)
41 189.75478 1.00000
42 149.91358 42.41577 1.5014548 (L216)
43 * 107.28888 1.06533
44 90.28791 31.06087 1.5014548 (L217: Lb)
45 ∞ 1.00000 1.47 (Lm)
46 ∞ 3.00000 1.5603261 (Lp)
47 ∞ 5.00000 1.47 (Lm)
(Wafer surface)

(Aspheric data)
2 sides κ = 0
C4 = 9.55755 × 10 ⁻⁹ C6 = 7.09690 × 10 ⁻¹³
C8 = 1.30845 × 10 ⁻¹⁶ C10 = −5.51522 × 10 ⁻²²
C12 = 4.46914 × 10 ⁻²⁵ C14 = −2.07483 × 10 ⁻²⁹

5 and 9 (same surface)
κ = 0
C4 = 1.16631 × 10 ⁻⁸ C6 = 6.770616 × 10 ⁻¹³
C8 = −1.87976 × 10 ⁻¹⁷ C10 = 1.71587 × 10 ⁻²⁰
C12 = −2.33487 × 10 ⁻²⁴ C14 = 1.90285 × 10 ⁻²⁸

16 faces κ = 0
C4 = −4.006017 × 10 ⁻⁸ C6 = 2.22513 × 10 ⁻¹²
C8 = −9.05000 × 10 ⁻¹⁷ C10 = 3.229839 × 10 ⁻²¹
C12 = −7.46596 × 10 ⁻²⁶ C14 = 1.06948 × 10 ⁻³⁰

17 faces κ = 0
C4 = −6.69592 × 10 ⁻⁸ C6 = 1.42455 × 10 ⁻¹²
C8 = −5.665516 × 10 ⁻¹⁷ C10 = 2.48078 × 10 ⁻²¹
C12 = −2.99163 × 10 ⁻²⁶ C14 = 1.53981 × 10 ⁻³¹

21 surface κ = 0
C4 = −7.997186 × 10 ⁻⁸ C6 = −1.32969 × 10 ⁻¹²
C8 = -1.98377 × 10 ⁻¹⁷ C10 = −4.995016 × 10 ⁻²¹
C12 = 2.53886 × 10 ⁻²⁵ C14 = −4.116817 × 10 ⁻²⁹

25 faces κ = 0
C4 = −1.55584 × 10 ⁻⁸ C6 = 7.267672 × 10 ⁻¹⁴
C8 = 1.90600 × 10 ⁻¹⁸ C10 = 1.21465 × 10 ⁻²³
C12 = −7.556829 × 10 ⁻²⁹ C14 = 1.86889 × 10 ⁻³²

39 surfaces κ = 0
C4 = −6.91993 × 10 ⁻¹¹ C6 = 7.880595 × 10 ⁻¹⁴
C8 = 3.3216 × 10 ⁻¹⁸ C10 = −1.39159 × 10 ⁻²²
C12 = 3.69991 × 10 ⁻²⁷ C14 = −4.001347 × 10 ⁻³²

43 planes κ = 0
C4 = 8.30019 × 10 ⁻⁸ C6 = 1.24781 × 10 ⁻¹¹
C8 = −9.26768 × 10 ⁻¹⁶ C10 = 1.08933 × 10 ⁻¹⁸
C12 = −3.01514 × 10 ⁻²² C14 = 5.41882 × 10 ⁻²⁶

(Values for conditional expressions)
F1 = 178.98mm
Y0 = 17.0mm
R = 20.86mm
(1) F1 / Y0 = 10.53
(2) R / Y0 = 1.227

  FIG. 8 is a diagram showing transverse aberration in the second example. As is apparent from the aberration diagram of FIG. 8, in the second embodiment, as in the first embodiment, a very large image-side numerical aperture (NA = 1.04) and a relatively large effective exposure area ER are secured. Nevertheless, it can be seen that the chromatic aberration is well corrected for exposure light having a wavelength width of 193.306 nm ± 0.1 pm.

  Thus, in each of the embodiments, a high image-side numerical aperture of 1.04 is secured for an ArF excimer laser beam having a wavelength of 193.306 nm, and an arc-shaped effective exposure region (26.0 mm × 4.0 mm) ( (Stationary exposure region) can be secured, and for example, a circuit pattern can be scanned and exposed at a high resolution in a rectangular exposure region of 26 mm × 33 mm.

  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. 9 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. 9, 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 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. 10, 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. ).

Then, in the module assembly step 404, the assembled liquid crystal panel (liquid crystal cell)
Each component such as an electric circuit and a backlight for performing the display operation is 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. Furthermore, 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 is applied to other general projection optical systems. Can also be applied.

Lb Boundary lens Lp Parallel plane plate Lm Medium (deionized water)
G1 First imaging optical system G2 Second imaging optical system CM1, CM2 Concave reflector Li Each lens component 100 Laser light source IL Illumination optical system R Reticle RS Reticle stage PL Projection optical system W Wafer WS Wafer stage

Claims (1)

In a catadioptric projection optical system that forms a reduced image of the first surface on the second surface,
The projection optical system includes at least two reflecting mirrors, and a boundary lens whose first surface side has a positive refractive power,
When the refractive index of the atmosphere in the optical path of the projection optical system is 1, the optical path between the boundary lens and the second surface is filled with a medium having a refractive index greater than 1.1,
All the transmissive members constituting the projection optical system and all the reflective members having refractive power are arranged along a single optical axis,
The projection optical system includes an effective imaging region having a predetermined shape that does not include the optical axis.

Images