JP2002072080A - Projection optical system and exposure device equipped therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a projection optical system excellent in the flatness of an image surface and restraining the fluctuation of a focal position caused by temperature change to be comparatively small while securing wide projection field and high resolving power. SOLUTION: This projection optical system projects the image of a pattern formed on a 1st surface (M) to a 2nd surface (P) at substantially unmagnified power. The projection optical system is equipped with a 1st part optical system (G1) and a 2nd part optical system (G2) constituted nearly symmetrically with the 1st part optical system with reference to the pupil surface (AS) of the projection optical system. The 1st part optical system has a pair of concave refraction surfaces in a first set arranged to be opposed to each other and a pair of concave refraction surfaces in a 2nd set arranged to be opposed to each other in an optical path between a pair of concave refraction surfaces in the 1st set.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a projection optical system and an exposure apparatus having the projection optical system, and more particularly to a method for manufacturing a micro device (semiconductor element, liquid crystal display element, thin film magnetic head, etc.) by a photolithography process. The present invention relates to a projection optical system that is most suitable for a projection exposure apparatus used for (1).

[0002]

2. Description of the Related Art In recent years, liquid crystal display panels have been frequently used as display elements for word processors, personal computers, televisions, and the like. The liquid crystal display panel is a glass substrate (plate)
It is manufactured by patterning a transparent thin film electrode on a desired shape by a photolithography technique. As an apparatus for the photolithography process, a projection exposure apparatus that projects and exposes an original pattern formed on a mask to a photoresist layer on a plate via a refraction type projection optical system is used. In particular, recently, high definition has been demanded by a liquid crystal display panel using low-temperature poly (polycrystalline) silicon, and a projection exposure apparatus having a high resolution over a wide field of view has been desired.

[0003]

Generally, in order to realize a projection exposure apparatus having a high resolution, it is necessary to set a large numerical aperture of a projection optical system to be mounted. On the other hand, the depth of focus of the projection optical system is inversely proportional to the square of the numerical aperture. For this reason, in a projection optical system having a large numerical aperture and high resolution, the depth of focus is narrow. In this case, the usable range of the depth of focus is further narrowed by the change in the focal position of the projection optical system due to the curvature of field of the projection optical system or the change in the ambient temperature (environmental temperature). As a result, it is necessary to take measures such as increasing the accuracy of the focus positioning and the accuracy of the temperature control in the apparatus, resulting in an inconvenience of increasing the cost of the apparatus. In addition, a high flatness is required for the glass substrate to be exposed, which has a disadvantage that the cost of the material is increased.

The present invention has been made in view of the above-mentioned problems, and has excellent flatness of an image plane and a relatively small change in a focal position due to a temperature change while securing a wide projection visual field and a high resolution. It is an object of the present invention to provide a projection optical system having good optical performance. Another object of the present invention is to provide an exposure apparatus and an exposure method capable of performing good exposure using a projection optical system having good optical performance without increasing the cost of the apparatus and materials. I do. Another object of the present invention is to provide a microdevice manufacturing method capable of manufacturing a good microdevice with a large area by good exposure using the above-described exposure apparatus.

[0005]

According to a first aspect of the present invention, an image of a pattern formed on a first surface is projected onto a second surface at substantially the same magnification. In the projection optical system, the projection optical system includes, in order from the first surface side, a first partial optical system and a first partial optical system configured to be substantially symmetric with respect to a pupil plane of the projection optical system. A first partial optical system, wherein the first partial optical system includes a first set of a pair of concave refraction surfaces arranged to face each other, and a first set of a pair of concave refraction surfaces. And a second set of a pair of concave refracting surfaces disposed so as to face each other in an optical path therebetween.

According to a preferred aspect of the first invention, the first partial optical system includes, in order from the first surface side, a first negative lens having a concave surface facing the second surface side; A second negative lens having a concave surface facing the first surface, a third negative lens having a concave surface facing the first surface, and a fourth negative lens having a concave surface facing the first surface.

According to a preferred aspect of the first invention,
The first partial optical system includes, in order from the first surface side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a second negative lens group having a positive refractive power. A positive lens group, wherein the first negative lens group has, in order from the first surface side, a first negative lens having a concave surface facing the second surface side, and a concave surface having a concave surface facing the second surface side. A second negative lens, a third negative lens having a concave surface facing the first surface, and a fourth negative lens having a concave surface facing the first surface; a focal length of the first partial optical system; Is F _1, and the focal length of the first negative lens group is f
_{When 1N} is satisfied, the condition of −0.4 <f _1N / F ₁ <0 is satisfied.

According to a second aspect of the present invention, in a projection optical system for projecting an image of a pattern formed on a first surface onto a second surface at substantially the same magnification, the projection optical system includes: 1
A first partial optical system, and a second partial optical system configured substantially symmetrically with respect to a pupil plane of the projection optical system with respect to a pupil plane of the projection optical system. A first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a second positive lens group having a positive refractive power, in order from the first surface side. When the rate of change of the refractive index n of the optical element with respect to the illumination light supplied to the projection optical system with respect to the ambient temperature T is represented by dn / dT, at least one negative lens constituting the second positive lens group is dn Provided is a projection optical system that satisfies the condition of / dT <0.

According to a preferred aspect of the second invention, at least one positive lens constituting the second positive lens group satisfies a condition of dn / dT> 0.

According to a third aspect of the present invention, in a projection optical system for projecting an image of a pattern formed on a first surface onto a second surface at substantially the same magnification, the projection optical system has an aspherical surface. , The distance along the optical axis between the first surface and the second surface is L,
The distance along the optical axis from the first surface to the aspheric surface is represented by L
Provided is a projection optical system characterized by satisfying the following condition: A: 0.035 <LA / L <0.3.

According to a preferred aspect of the third invention, the projection optical system has a first aspheric surface and a second aspheric surface arranged symmetrically with respect to a pupil plane of the projection optical system, and The distance along the optical axis between the surface and the second surface is L,
When the distance along the optical axis from the surface to the first aspherical surface is LA, the condition 0.035 <LA / L <0.3 is satisfied.

According to a fourth aspect of the present invention, an image of the mask pattern formed on the first surface is converted into a second image on a photosensitive substrate.
In a projection optical system for lithography that projects onto a surface,
The projection optical system includes a first aspherical surface and a second aspherical surface, and the first aspherical surface and the second aspherical surface have the same shape as each other. provide.
According to a fifth aspect of the present invention, in the method for manufacturing a projection optical system for lithography for projecting an image of a mask pattern formed on a first surface onto a second surface on which a photosensitive substrate is disposed, a plurality of optical elements are provided. A first step of preparing, and forming at least two of the plurality of prepared optical elements with an aspherical surface of a predetermined shape to obtain at least a first aspherical optical element and a second aspherical optical element. 2. A projection, comprising: two steps; a third step of inspecting the surface shapes of the first and second aspherical optical elements; and a fourth step of arranging the optical elements along a predetermined optical axis. An optical system manufacturing method is provided.

According to a sixth aspect of the present invention, there is provided a projection optical system manufactured by the manufacturing method of the fifth aspect. According to a seventh aspect of the present invention, there is provided the projection optical system according to any one of the first to fourth and sixth aspects, and an illumination optical system for illuminating a mask set on the first surface, wherein the projection optical system An exposure apparatus for exposing a pattern formed on the mask to a photosensitive substrate set on the second surface through a system.

In an eighth aspect of the present invention, an exposure step of exposing the pattern of the mask to the photosensitive substrate using the exposure apparatus of the seventh aspect, and the step of exposing the photosensitive substrate exposed through the exposure step to And a developing step of developing. According to a ninth aspect of the present invention, an illumination step of illuminating a mask on which a predetermined pattern is formed and the projection optical system of the first to fourth and sixth aspects of the present invention are used to set the mask on the first surface. Exposing the pattern of the mask to the photosensitive substrate set on the second surface.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A projection optical system according to a typical embodiment of the present invention includes a first partial optical system G1, an aperture stop AS, and an aperture stop AS in this order from a first surface side (object surface side). It comprises a first partial optical system G1 and a second partial optical system G2 which is substantially symmetrical. Therefore, the image of the pattern formed on the first surface as the object surface is projected at substantially the same magnification on the second surface as the image surface. Hereinafter, in order to simplify the description, the second partial optical system G
2 is symmetrical to the first partial optical system G1 with respect to the aperture stop, and assuming a case where the projection magnification of the projection optical system is the same, the present invention will be described focusing on only the first partial optical system G1. .

As described above, in a projection optical system having a high resolution, the depth of focus is narrow. Therefore, in order to make full use of this narrow depth of focus, the amount of curvature of field must be reduced, that is, the flatness is excellent. It is necessary to secure an image plane. Therefore, in order to favorably correct the Petzval sum of the projection optical system, the first partial optical system G having a positive refractive power has
In 1, a lens group G _1N having a negative refractive power is arranged. However, when the negative refracting power of the negative lens group G _1N becomes strong, it becomes difficult to correct coma.

In the present invention, in order to satisfactorily correct the coma generated when the Petzval sum of the projection optical system (and thus the curvature of field thereof) is satisfactorily corrected, the first set arranged so as to face each other. A pair of concave refracting surfaces, and a second pair of concave refracting surfaces arranged to face each other in an optical path between the first pair of concave refracting surfaces. It is arranged in one partial optical system G1. With this configuration, according to the present invention, it is possible to realize a projection optical system having excellent flatness of the image surface while securing a wide projection field of view and high resolution.

According to a more specific aspect, the first partial light
The science system G1 has a positive refractive power in order from the first surface side.
1 positive lens group G_1PAnd a first negative lens having a negative refractive power
Group G _1NAnd a second positive lens group G having a positive refractive power_2PAnd
It is composed of Then, the first negative lens group G_1NIs the
A first negative lens having a concave surface facing the second surface in order from the first surface
A second negative lens having a concave surface facing the second surface, and a first surface
A third negative lens with a concave surface facing the surface, and a concave surface with the concave surface facing the first surface
And a fourth negative lens. In this case, the first
The concave surface on the second surface side of the negative lens and the first surface of the fourth negative lens
Side concave surface constitutes a pair of concave surface refraction surfaces of a first set,
The concave surface on the second surface side of the second negative lens and the concave surface of the third negative lens
The concave surface on one side constitutes a second pair of concave refracting surfaces.
are doing.

In the present invention, it is desirable that the above-described configuration satisfies the following conditional expression (1). −0.4 <f _1N / F ₁ <0 (1) Here, F ₁ is the focal length of the first partial optical system G1. F _1N is the focal length of the first negative lens group G _1N .

[0020] Condition (1) defines an appropriate range for the ratio of the focal length F ₁ of the focal length f _1N and the first partial optical system G1 of the first negative lens group G _1N. If the lower limit of conditional expression (1) is not reached, the negative refracting power of the first negative lens unit G _1N becomes too weak, and it becomes difficult to satisfactorily correct the curvature of field, which is not preferable. In order to sufficiently exhibit the effects of the present invention, it is more preferable to set the lower limit of conditional expression (1) to -0.3 and the upper limit to -0.1.

Further, as described above, in a projection optical system having a high resolution, the depth of focus is narrow. Therefore, in order to make full use of this narrow depth of focus, the focal position of the projection optical system due to a change in ambient temperature must be adjusted. It is necessary to keep the fluctuation (that is, the position fluctuation along the focusing direction of the imaging plane of the projection optical system) small. The first partial optical system G1 sequentially includes, from the first surface side, a first positive lens group G _1P having a positive refractive power, a first negative lens group G _1N having a negative refractive power, and a positive refractive power. If and a second positive lens group G _2P with, the focus position caused by temperature changes in the second positive lens group G _2P disposed in the vicinity of the near i.e. aperture stop aS of the pupil plane of the projection optical system The effect of fluctuation is considered to be the largest.
In other words, in order to suppress the change in the focal position of the projection optical system due to the change in the ambient temperature, it is necessary to suppress the change in the focal position caused by the temperature change in the second positive lens group _G2P .

However, the second positive lens group G _2P is
Since the positive optical power of the partial optical system G1 plays a major role, it is necessary to appropriately correct the chromatic aberration in the second positive lens group _G2P . Therefore, an anomalous dispersion glass material such as CaF ₂ (fluorite) is often used for the positive lens constituting the second positive lens group G _2P . At this time, since the rate of change of the refractive index dn / dT with respect to the ambient temperature T has a negative value in an anomalous dispersion glass material such as CaF ₂ , the focus generated by the temperature change dT in the second positive lens group G _2P . The position variation, that is, the variation rate ΔFD / dT, has a relatively large positive value. Here, the variation amount Δ of the focal position
The FD takes a positive sign when the imaging plane of the projection optical system fluctuates in a direction away from the object plane, and takes a negative sign when the imaging plane of the projection optical system fluctuates in a direction approaching the object plane. Shall be.

In the present invention, at least one negative lens constituting the second positive lens group G _2P is required to _{satisfy the} following conditional expression (2) in order to suppress a change in the focal position of the projection optical system due to a change in ambient temperature. Satisfies. dn / dT <0 (2)

By satisfying conditional expression (2), the value of the fluctuation rate ΔFD / dT of the focal position of the projection optical system caused by the change in the ambient temperature dT is derived from a relatively large positive value to a negative direction. Thus, the fluctuation of the focal position of the projection optical system due to the change of the ambient temperature can be suppressed. With this configuration, according to the present invention, it is possible to realize a projection optical system with a relatively small change in the focal position due to a temperature change, while securing a wide projection field of view and a high resolution.

In the present invention, at least one positive lens constituting the second positive lens group G _2P must _{satisfy the} following conditional expression in order to further suppress the fluctuation of the focal position of the projection optical system due to a change in ambient temperature. It is preferable to satisfy (3). dn / dT> 0 (3)

By satisfying conditional expression (3), the value of the fluctuation rate ΔFD / dT of the focal position of the projection optical system caused by the change dT in the ambient temperature is led from a relatively large positive value to the negative direction. This is preferable because it is possible to further suppress the fluctuation of the focal position of the projection optical system due to the change in the ambient temperature.

Further, in the present invention, the projection optical system has an aspheric surface, and this aspheric surface satisfies the following expression (4). 0.035 <LA / L <0.3 (4) Here, L is a distance along the optical axis between the first surface and the second surface. LA is a distance along the optical axis from the first surface to the aspheric surface.

By satisfying conditional expression (4), the first condition
The aspherical surface is arranged at a position relatively close to the surface. in this case,
The positions where the light rays having different image heights are incident on the aspherical surface are easily separated from each other, and the field curvature can be corrected well.
In the case where the projection optical system is configured to be approximately the same magnification and configured substantially symmetrically with respect to the pupil plane, the aspherical surface is also arranged at a position relatively close to the second surface. In this case, the projection optical system has a first aspheric surface and a second aspheric surface symmetrically arranged with respect to the pupil plane, and it is desirable that the first aspheric surface satisfies the conditional expression (4).

As described above, in the projection optical system of the present invention,
Good optical performance with excellent flatness of the image plane and relatively little change in the focal position due to temperature change can be achieved while securing a wide projection field of view and high resolution. Therefore, according to the exposure apparatus and the exposure method of the present invention, favorable exposure can be performed using the projection optical system of the present invention having good optical performance without increasing the cost of the apparatus and materials. Further, according to the present invention, a good microdevice having a large area can be manufactured by favorable exposure using the exposure apparatus of the present invention.

An embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a view schematically showing a configuration of an exposure apparatus including a projection optical system according to an embodiment of the present invention. In FIG. 1, a plate (glass substrate) which is a photosensitive substrate
1 along the normal direction of FIG.
Are set in the direction parallel to the plane of FIG. 1, and the X axis is set in the direction perpendicular to the plane of FIG. 1 in the plane of the plate.

The exposure apparatus shown in FIG. 1 has a light source 1 composed of, for example, a high-pressure mercury lamp. The light source 1 is positioned at a first focal position of an elliptical mirror 2 having a reflection surface formed of a spheroid. Therefore, the illumination light flux emitted from the light source 1 forms a light source image at the second focal position of the elliptical mirror 2 via the mirror 3. The light beam from the light source image formed at the second focal position of the elliptical mirror 2 is converted into a substantially parallel light beam by the collimator lens 4 and then passed to a wavelength selection filter 5 for selectively transmitting a light beam in a desired wavelength range. Incident. In the case of the present embodiment, in the wavelength selection filter 5, i
Only light of the line (λ = 365 nm) is selectively transmitted.

Light (i-line light) having an exposure wavelength selected through the wavelength selection filter 5 is incident on a fly-eye lens 6 as an optical integrator. The fly-eye lens 6 is formed by arranging a large number of lens elements having a positive refractive power vertically and horizontally and densely so that their optical axes are parallel to the reference optical axis AX. Each lens element constituting the fly-eye lens 6 has a rectangular cross-section similar to the shape of the illumination field to be formed on the mask (and the shape of the exposure area to be formed on the plate). In addition, the surface on the incident side of each lens element constituting the fly-eye lens 6 is formed in a spherical shape with the convex surface facing the incident side, and the surface on the emitting side is formed in a spherical shape with the convex surface facing the emitting side. .

Therefore, the light beam incident on the fly-eye lens 6 is split into wavefronts by a number of lens elements.
One light source image is formed on the rear focal plane of each lens element. In other words, on the rear focal plane of the fly-eye lens 6, a substantial surface light source, that is, a secondary light source composed of many light source images is formed. The luminous flux from the secondary light source formed on the rear focal plane of the fly-eye lens 6 enters the aperture stop 7 disposed near the secondary light source. The aperture stop 7 is arranged at a position optically substantially conjugate with an entrance pupil plane of the projection optical system PL, which will be described later, and has a variable aperture for defining a range contributing to illumination of the secondary light source. The aperture stop 7 changes the aperture diameter of the variable aperture to determine the illumination condition (the ratio of the aperture of the secondary light source image on the pupil plane to the aperture diameter of the pupil plane of the projection optical system). Is set to the desired value.

The light from the secondary light source through the aperture stop 7 is
After receiving the light-condensing action of the condenser optical system 8, the mask M on which a predetermined pattern is formed is uniformly illuminated in a superimposed manner.
The light beam transmitted through the pattern of the mask M is projected onto the projection optical system PL.
, An image of a mask pattern is formed on a plate P which is a photosensitive substrate. In this manner, by performing collective exposure or scan exposure while controlling and driving the plate P two-dimensionally in a plane (XY plane) orthogonal to the optical axis of the projection optical system PL, the mask M Are sequentially exposed.

In the batch exposure, a so-called step
According to the AND-repeat method, the mask pattern is collectively exposed to each exposure area of the plate. In this case, the shape of the illumination area on the mask M is a rectangular shape close to a square, and the cross-sectional shape of each lens element of the fly-eye lens 6 is also a rectangular shape close to a square. On the other hand, in scan exposure, according to a so-called step-and-scan method, a mask pattern is subjected to scan exposure (scan exposure) on each exposure region of the plate while moving the mask and plate relative to the projection optical system. In this case, the shape of the illumination area on the mask M is a rectangular shape having a ratio of the short side to the long side of, for example, 1: 3, and the cross-sectional shape of each lens element of the fly-eye lens 6 is similar to this. Becomes

FIG. 2 shows a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a lens configuration of a projection optical system according to an example. The projection optical system PL according to the first example includes, in order from the object side (that is, the mask M side), a first partial optical system G1;
It comprises an aperture stop AS and a second partial optical system G2 which is symmetrical to the first partial optical system G1 with respect to the aperture stop AS. In other words, the second partial optical system G2
Is configured symmetrically with respect to the aperture stop AS arranged on the pupil plane of the projection optical system PL with respect to the first partial optical system G1 in its lens shape, its lens interval, and its optical material. Therefore, the projection optical system P according to the first embodiment
L has the same projection magnification.

The first partial optical system G1 is, in order from the object side,
It comprises a first positive lens group G _1P having a positive refractive power, a first negative lens group G _1N having a negative refractive power, and a second positive lens group G _2P having a positive refractive power. And the first
The positive lens group G _1P includes, in order from the object side, a biconcave lens L _1P1 , a biconvex lens L _1P2 , a biconvex lens L _1P3 , a biconvex lens L _{1 P4} , and a positive meniscus lens L _1P5 having a convex surface facing the object side. I have.

The first negative lens group G _1N includes, in order from the object side, a refractive surface r having a concave surface facing the image side (the plate P side).
A negative meniscus lens L _1N1 having _1N12, biconcave lens L _1N2 having a refractive surface r _1N22 having a concave surface directed toward the image side, a negative meniscus lens having a refracting surface r _1N31 having a concave surface facing the object side L _1N3, and the object side It is composed of a biconcave lens _L1N4 having a refractive surface _r1N41 with a concave surface. That is, the refraction surface r _1N12 and the refraction surface r _{1N41 constitute} a first pair of concave refraction surfaces arranged to face each other. Further, the refraction surface r _1N22 and the refraction surface r _1N31
Constitutes a second pair of concave refraction surfaces arranged to face each other in the optical path between the first pair of concave refraction surfaces.

Further, the second positive lens group G _2P includes, in order from the object side, a positive meniscus lens L having a concave surface facing the object side.
_2P1, biconvex lens L _2P2, biconvex lens L _2P3, consists object negative meniscus lens L _{2 P4} a concave surface facing the side, biconvex lens L _2P5, positive meniscus lens L _2P6 a convex surface facing the object side, and a biconcave lens L _2P7 Have been. Here, the positive meniscus lens L _2P1 , the biconvex lens L _2P2 , the biconvex lens L _2P3 , and the biconvex lens L _2P5 are formed of an anomalous dispersion glass material, and the change rate dn / dT of the refractive index n with respect to the change of the ambient temperature T. Has a negative value. As the anomalous dispersion glass material, for example, S-FPL51Y (trademark) or FPL51Y (trademark) manufactured by OHARA CORPORATION, FK51 manufactured by SCHOTT (SCHOTT), or their equivalents can be used. In addition, the biconcave lens L
_2P7 constitutes a negative lens which satisfies the condition of a change rate dn _2P7 / dT <0 of the refractive index n with respect to a change in the ambient temperature T. Further, the positive meniscus lens L _2P6 has a change rate dn _{2 P6} / dT of the refractive index n with respect to the change of the ambient temperature T.
The positive lens satisfies the condition of> 0.

On the other hand, the second partial optical system G2 includes, in order from the object side, a third positive lens group G _3P having a positive refractive power, a second negative lens group G _2N having a negative refractive power, and a positive And a fourth positive lens group G _4P having a refractive power. As described above, the second partial optical system G2 is configured symmetrically to the first partial optical system G1 with respect to the aperture stop AS. That is, the third positive lens group G _3P is the second positive lens group G _3P with respect to the aperture stop AS.
Is configured positive lens group G _2P Symmetrically, a second negative lens group G
_2N is configured symmetrically to the first negative lens group G _1N with respect to the aperture stop AS, and the fourth positive lens group G _4P is configured symmetrically to the first positive lens group G _1P with respect to the aperture stop AS.

Therefore, the third positive lens group G _3P includes, in order from the image side, a positive meniscus lens L having a concave surface facing the image side.
_3P1, biconvex lens L _3P2, biconvex lens L _3P3, negative meniscus lens with its concave surface facing the image side L _3P4, biconvex lens L _3P5,
It is composed of a positive meniscus lens L _{3P6 with} a convex surface facing the image side, and a biconcave lens L _3P7 . Here, a positive meniscus lens L _3P1, biconvex lens L _3P2, biconvex lens L
_3P3 and the biconvex lens _L3P5 are formed of the above-mentioned anomalous dispersion glass material, and the change rate dn / dT of the refractive index n with respect to the change of the ambient temperature T has a negative value. The biconcave lens L _3P7 has a refractive index n with respect to a change in the ambient temperature T.
_Is a negative lens that satisfies the condition of change rate dn _3P7 / dT <0. Further, the positive meniscus lens L
_3P6 constitutes a positive lens which satisfies the condition of a change rate dn _3P6 / dT> 0 of the refractive index n with respect to a change in the ambient temperature T.

The second negative lens group G_2NIs the order from the image side
A refracting surface r with the concave surface facing the object side _2N11Negative menu with
Sukas lens L_2N1, A refractive surface r with the concave surface facing the object side
_2N21Biconcave lens L having_2N2With concave surface facing the image side
Curved surface_2N32Negative meniscus lens L having_2N3,and
Refraction surface r with concave surface facing image side_2N42Biconcave lens L having
_{Two N4}It is composed of That is, the refraction surface r_2N11And
And refraction surface r_2N42Are the first
One set of a pair of concave refraction surfaces is formed. Also,
Refraction surface r_2N21And the refractive surface r_2N32Is a first pair of concaves
Opposing each other in the optical path between the surface-shaped refraction surfaces.
A pair of concave refraction surfaces arranged in a second set
are doing.

The fourth positive lens group G _4P includes, in order from the image side, a biconcave lens L _4P1 , a biconvex lens L _4P2 , a biconvex lens L _4P3 , a biconvex lens L _4P4 , and a positive meniscus lens having a convex surface facing the image side. _L4P5 .

Table 1 below summarizes the data values of the projection optical system of the first embodiment. In the main specifications of Table (1), N
A is the numerical aperture on the object side (the same is true for the image side), Y
0 indicates the maximum image height, respectively. In the optical member specifications of Table (1), the surface number of the first column indicates the order of the surface along the light traveling direction from the object side, and the r of the second column.
Indicates the radius of curvature (mm) of each surface, d in the third column indicates the on-axis interval of each surface, that is, the surface interval (mm), and n in the fourth column indicates the refractive index for exposure light (λ = 365 nm). ing.

[0045]

[Table 1]

FIG. 3 is a diagram showing spherical aberration, astigmatism, and distortion of the projection optical system in the first embodiment. FIG. 4 is a diagram illustrating coma aberration of the projection optical system in the first example. In each aberration diagram, NA indicates the numerical aperture on the object side, and Y indicates the image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a tangential image plane. As is clear from the aberration diagrams, in the projection optical system of the first embodiment,
Various aberrations are satisfactorily corrected over the entire large projection field of view (effective diameter 142 mm), and good optical performance is secured. In particular, with reference to the astigmatism diagram, the flatness of the image plane is well secured. You can see that it is. Also, referring to the value of the fluctuation rate ΔFD / dT of the focal position in the value corresponding to the conditional expression in Table (1), in the projection optical system of the first embodiment, the fluctuation of the focal position due to the change in the ambient temperature is relatively small. You can see that it is done.

[Second Embodiment] FIG. 5 shows a second embodiment of the present invention.
FIG. 2 is a diagram illustrating a lens configuration of a projection optical system according to an example.
You. In the second embodiment, similarly to the first embodiment, the projection optical system
PL is, in order from the object side, a first partial optical system G1 and an aperture.
A stop AS and a first partial optical system related to the aperture stop AS
G1 and the second partial optical system G2 configured symmetrically.
And has an equal magnification. Also, the first partial optics
As in the first embodiment, the system G1 also has a positive flexure in order from the object side.
First positive lens group G having folding power_1PHas a negative refractive power
First negative lens group G_1NAnd a second positive lens having a positive refractive power.
Group G_2PIt is composed of Therefore, Part 2
Similarly to the first embodiment, the spectroscopic system G2 is also arranged in order from the object side.
Third positive lens group G having a positive refractive power_3PAnd negative refractive power
Second negative lens group G having _2NAnd a positive refractive power
4 positive lens group G_4PIt is composed of

More specifically, in the second embodiment, the first positive lens group G _1P includes, in order from the object side, a negative meniscus lens L _1P1 having an aspheric concave surface facing the object side, and a biconvex lens. L _1P2 , biconvex lens L _1P3 , biconvex lens L _1P4 ,
And a biconvex lens _L1P5 . The first negative lens group G _1N, in order from the object side, a negative meniscus lens L _1N1 having a refractive surface r _1N12 with its concave surface formed in an aspherical shape on the image side, a concave surface facing the image side refractive Surface r _1N22
Biconcave lens L _1N2, biconcave lens having a refracting surface r _1N41 having a concave surface facing the negative meniscus lens L _1N3, and the object side has a refractive surface r _1N31 having a concave surface facing the object side L with
_It consists of _1N4 . That is, the refraction surface r _1N12 and the refraction surface r _{1N41 constitute} a first pair of concave refraction surfaces arranged to face each other. Also,
The refraction surface r _1N22 and the refraction surface r _{1N31 constitute} a second set of a pair of concave refraction surfaces arranged so as to face each other in an optical path between the first set of a pair of concave refraction surfaces. ing.

The second positive lens group G _2P includes, in order from the object side, a biconvex lens L _2P1 , a positive meniscus lens L _2P2 having a concave surface _facing the object side, a biconvex lens L _2P3 , and a negative lens having a concave surface _facing the object side. Meniscus lens L _2P4 , biconvex lens L _2P5 ,
It is composed of a positive meniscus lens L _2P6 having a convex surface facing the object side, and a biconcave lens L _2P7 . Here, the biconvex lens _L2P1 , the positive meniscus lens _L2P2 , the biconvex lens L
_2P3 and the biconvex lens _L2P5 are formed of a glass material having anomalous dispersion, and the change rate dn / dT of the refractive index n with respect to the change of the ambient temperature T has a negative value. As the glass material having anomalous dispersion, the materials described in the first embodiment can be used. Further, the biconcave lens L _2P7 has a change rate dn _2P7 / dT <of the refractive index n with respect to a change in the ambient temperature T.
This constitutes a negative lens satisfying the condition 0. further,
The positive meniscus lens L _2P6 constitutes a positive lens that satisfies the condition that the change rate of the refractive index n with respect to the change of the ambient temperature T is dn _2P6 / dT> 0.

On the other hand, the negative third positive lens group G _3-Way is directed in order from the image side, a biconvex lens L _3P1, positive meniscus lens L _3P2 having a concave surface facing the image side, a biconvex lens L _3P3, a concave surface on the image side It comprises a meniscus lens L _3P4 , a biconvex lens L _3P5 , a positive meniscus lens L _3P6 having a convex surface _facing the image side, and a biconcave lens L _3P7 . Here, biconvex lens L _{3-Way 1,} a positive meniscus lens L _3P2, biconvex lens L _3P3,
The biconvex lens L _3P5 is formed of the above-described anomalous dispersion glass material, and has a refractive index n with respect to a change in the ambient temperature T.
Has a negative value. The biconcave lens L _3P7 constitutes a negative lens that satisfies the condition of a change rate dn _3P7 / dT <0 of the refractive index n with respect to a change in the ambient temperature T. Further, the positive meniscus lens L _3P6 has a change rate dn _3P6 /
The positive lens satisfies the condition of dT> 0.

The second negative lens group G _2N includes, in order from the image side, a negative meniscus lens L _2N1 having a refracting surface r _2N11 with the aspherical concave surface _facing the object side, and a concave surface on the object side. _Bi- concave lens L _2N2 having a refractive surface r _2N21 directed toward the lens, a negative meniscus lens L _2N3 having a refractive surface r _{2N3 2} having a concave surface facing the image side, and a bi-concave lens L having a refractive surface r _2N42 having a concave surface facing the image side. _It consists of _2N4 . That is, the refraction surface r _2N11 and the refraction surface r _{2N42 constitute} a first pair of concave refraction surfaces arranged to face each other. Further, the refraction surface r _2N21 and the refraction surface r _2N32
Constitutes a second pair of concave refraction surfaces arranged to face each other in the optical path between the first pair of concave refraction surfaces.

Further, the fourth positive lens group G _4P includes, in order from the image side, a negative meniscus lens L _4P1 , a biconvex lens L _4P2 , and a biconvex lens L _having an aspheric concave surface facing the image side.
_4P3 , a biconvex lens _L4P4 , and a biconvex lens _L4P5 .

In the second embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is defined as y, and the aspheric surface is defined by the optical axis from the tangent plane at the vertex of the aspheric surface to a position on the aspheric surface at height y. When the distance (sag amount) along the axis is x, the radius of curvature at the vertex is r, the cone coefficient is κ, and the n-th order aspheric coefficient is C _n , the following equation (a) is obtained.

[Number 1] ^{x = (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 (a) In the second embodiment, the aspherical lens surface is marked with an asterisk on the right side of the surface number.

Table 2 below summarizes the data values of the projection optical system of the second embodiment. In the main specifications of Table (2), N
A is the numerical aperture on the object side (the same is true for the image side), Y
0 indicates the maximum image height, respectively. Also, in the optical member specifications of Table (2), the surface number of the first column indicates the order of the surface along the ray traveling direction from the object side, and the r of the second column.
Is the radius of curvature of each surface (vertical radius of curvature: m for an aspheric surface)
m), d in the third column is the axial interval of each surface, that is, the surface interval (mm), and n in the fourth column is exposure light (λ = 365n).
m) are shown respectively.

[0055]

[Table 2] (Aspherical surface data) First surface (object-side surface of lens L _1P1 ) r = −253.3355 κ = 0 C ₄ = 0.2774 × 10 ⁻⁷ C ₆ = −0.2678 × 10 ⁻¹¹ C _{8 ^{= 0.4415 × 10 -16 C 10 =}} -0.2422 × 10 -20 C 12 = -0.1025 × 10 -24 ( the image-side surface of the lens L _1N1) twelfth surface r = 153.1279 κ = 0 C ₄ = 0.3368 × 10 ⁻⁷ C ₆ = −0.2900 × 10 ⁻¹² C ₈ = 0.1071 × 10 ⁻¹⁶ C ₁₀ = −0.8637 × 10 ⁻²¹ C ₁₂ = −0.1625 × 10 ⁻²⁴ 54th surface (surface on the object side of lens L _2N1 ) r = −1533.1279 κ = 0 C ₄ = −0.3368 × 10 ⁻⁷ C ₆ = 0.2900 × 10 ⁻¹² C ₈ = -0.1071 × ₁₀ ^-16 C 10 = (surface on the image side of the lens _{^{L 4P1) 0.8637 × 10 -21 C}} 12 = 0.1625 × 10 -24 65th surface r = 253.3 _{55 κ = 0 C 4 = -0.2774} × 10 -7 C 6 = 0.2678 × 10 -11 C 8 = -0.4415 × 10 -16 C 10 = 0.2422 × 10 -20 C 12 = 0 .1025 × 10 ⁻²⁴ (values corresponding to conditional expressions) F ₁ = 350.3 f _1N = −72.9 ΔFD / dT = 20.8 μm (1) f _1N / F ₁ = −0.21 (f _2N / F ( ₂ = −0.21) (2) dn _2P7 /dT=−4.6×10 ⁻⁶ (dn _3P7 /dT=−4.6×10 ⁻⁶ ) (3) dn _2P6 /dT=11.0× 10 ^-6 (dn _3P6 /dT=11.0×10 ^-6 )

FIG. 6 is a diagram showing the spherical aberration, astigmatism and distortion of the projection optical system in the second embodiment. FIG. 7 is a diagram showing coma aberration of the projection optical system in the second example. In each aberration diagram, NA indicates the numerical aperture on the object side, and Y indicates the image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a tangential image plane. As is clear from the aberration diagrams, the projection optical system according to the second embodiment also has a large projection field (effective diameter 14) as in the first embodiment.
It can be seen that various aberrations are satisfactorily corrected over the entire area of 2 mm), and good optical performance is secured. In particular, with reference to the astigmatism diagram, it is understood that the flatness of the image plane is well secured. Further, referring to the value of the fluctuation rate ΔFD / dT of the focal position in the values corresponding to the conditional expressions in Table (2), the projection optical system according to the second embodiment also has the focus due to the change in the ambient temperature, as in the first embodiment. It can be seen that the change in position is relatively small.

In each of the above-described embodiments, the present invention is applied to an equal-magnification optical system which is completely symmetrical with respect to the pupil plane (aperture stop AS). The focal length of the first partial optical system G1 and the second partial optical system G2
The projection magnification can be slightly changed by changing the ratio with respect to the focal length. In this state where the projection magnification is slightly changed from the unity magnification, the projection optical system is in a state of being substantially symmetrical with respect to the pupil plane. In other words, in the present invention, the state of “substantially symmetric with respect to the pupil plane” includes a state in which the projection magnification is changed from the unity magnification.

[Method of Manufacturing Projection Optical System] Next, a method of manufacturing the projection optical system according to the second embodiment will be described with reference to FIGS. In the second embodiment, a method of manufacturing the projection optical system according to the second example of the first embodiment having two aspheric surfaces having the same shape will be described.

FIG. 9 is a flowchart showing a manufacturing flow of a method for manufacturing a projection optical system according to the second embodiment of the present invention. In the manufacturing method according to the second embodiment, after manufacturing a block glass material (blanks) on which each lens is to be formed, the absolute value of the refractive index and the refractive index distribution of the manufactured block glass material are measured by, for example, an interferometer apparatus shown in FIG. The measurement is performed using (S11). In FIG. 10, a block glass material 103 as a test object is installed at a predetermined position in a sample case 102 filled with oil 101. Then, the emission light from the interferometer unit 105 controlled by the control system 104 enters a Fizeau flat (Fizeau plane) 106 supported on a Fizeau stage 106a.

Here, the light reflected by the Fizeau flat 106 becomes reference light and returns to the interferometer unit 105.
On the other hand, the light transmitted through the Fizeau flat 106 becomes measurement light, and is incident on the test object 103 in the sample case 102. The light transmitted through the test object 103 is reflected by the reflection plane 107 and returns to the interferometer unit 105 via the test object 103 and the Fizeau flat 106. Thus, based on the phase shift between the reference light and the measurement light returned to the interferometer unit 105, the wavefront aberration due to the refractive index distribution of each block glass material 103 as an optical material is measured. For details regarding the measurement of the refractive index homogeneity using an interferometer, reference can be made to, for example, JP-A-8-5505. In the second embodiment, information on the measured refractive index distribution is stored in a predetermined storage device for each block glass material 103.

Next, in the manufacturing method of the second embodiment, each lens to constitute the projection optical system is manufactured using a block glass material which is ground as necessary from a block glass material whose refractive index distribution has been measured. That is, the surface of each lens is polished with a design value as a target according to a well-known polishing process to produce a spherical lens having a spherical lens surface and an aspheric lens having an aspheric lens surface ( S12). In the polishing step, polishing is repeated while measuring the error in the surface shape of each lens with an interferometer, and the surface shape of each lens is brought closer to the target surface shape (best-fit spherical shape). Thus, when the surface shape error of each lens falls within a predetermined range, the error of the surface shape of each lens is measured using, for example, a more precise interferometer device shown in FIG. 11 (S1).
3).

The interferometer apparatus shown in FIG. 11 is suitable for measuring the surface shape of a spherical lens having a spherical design value. In FIG. 11, the interferometer unit 1 controlled by the control system 111
The light emitted from the lens 12 enters the Fizeau lens 113 supported on the Fizeau stage 113a. Here, the light reflected on the reference surface (Fizeau surface) of the Fizeau lens 113 becomes reference light and returns to the interferometer unit 112. Although the Fizeau lens 113 is shown as a single lens in FIG. 11, an actual Fizeau lens is composed of a plurality of lenses (lens groups). On the other hand, Fizeau lens 11
The light transmitted through 3 becomes measurement light and is incident on the optical surface of the lens 114 to be measured.

The measurement light reflected by the optical surface of the lens 114 to be measured returns to the interferometer unit 112 via the Fizeau lens 113. Thus, based on the phase shift between the reference light and the measurement light returned to the interferometer unit 112, the wavefront aberration of the test optical surface of the test lens 114 with respect to the reference surface is
Consequently, an error in the surface shape of the test lens 114 (deviation from the designed best-fit spherical surface) is measured. For details regarding the measurement of the surface shape error of the spherical lens by the interferometer, for example, Japanese Patent Application Laid-Open Nos. 7-12535, 7-113609, and 10-154657 can be referred to.

When the surface shape error of the aspherical lens is measured using an interferometer, a reference member having a planar reference surface is used instead of the Fizeau lens 113 in the interferometer apparatus of FIG. An aspherical wave forming member for converting light transmitted through the reference member into an aspherical wave having a predetermined shape is provided on the Fizeau stage 113a. Here, the aspherical wave forming member is configured by a lens, a zone plate, or a combination thereof, and converts a plane wave from the reference member into an aspherical wave corresponding to the surface shape of the optical surface to be measured as the measurement target. Things. For the method of measuring such an aspherical lens, for example, JP-A-10-260020, JP-A-10-260024, and JP-A-11-6678 can be referred to.

When measuring an aspherical shape by the above-described method, it is necessary to prepare an aspherical wave forming member according to the number of types of shapes of the aspherical lens surface as the optical surface to be measured. When the number of aspherical surfaces in the projection optical system increases, the types of aspherical wave forming members also increase, and the design and manufacture of the members tend to be a great burden. Furthermore, in the case where the number of aspherical shape measuring devices is limited, if the types of aspherical surfaces used in the projection optical system increase, a plurality of types of aspherical waves are generated according to the type of aspherical surface to be measured. A step of replacing the formed member is required, and the manufacturing time tends to be long.

However, in the projection optical system according to the manufacturing method of the second embodiment (ie, the projection optical system of the second example of the first embodiment), two of the four aspheric surfaces have the same shape. Since the remaining two surfaces are formed in the same shape as each other, two types of aspherical wave forming members may be prepared, and the cost (design cost, manufacturing cost) and the cost of manufacturing the projection optical system are reduced. This is very advantageous in reducing the manufacturing time.

Thereafter, it is determined whether or not the measured surface shape falls within a predetermined range (S14). Here, when the measured surface shape is not within the predetermined range (NG in FIG. 9)
), The process proceeds to the polishing step (S12). If the measured surface shape is within the predetermined range (OK in FIG. 9), the process proceeds to the next assembling step (S15).

In the assembling step, the projection optical system 26 is assembled using a plurality of lenses whose errors are within a predetermined range (S15). More specifically, each optical unit is sequentially assembled by holding a plurality of lenses in a predetermined holding frame according to design values. Then, the assembled optical units are sequentially dropped into the lens barrel through the upper opening of the lens barrel. At this time, a predetermined washer is interposed between the optical units. In this way, the optical unit first dropped into the lens barrel is supported via the washer at the protrusion formed at one end of the lens barrel, and all the optical units are accommodated in the lens barrel, thereby projecting the optical projection unit. The assembly of the system is completed. For details regarding the assembly of the projection optical system, reference can be made to, for example, Japanese Patent Application Laid-Open No. H10-154657.

Next, in the manufacturing method of the second embodiment, the wavefront aberration of the actually assembled projection optical system is measured (S16). Specifically, for example, Japanese Patent Application Laid-Open No. 10-387
The wavefront aberration of a projection optical system using an ultra-high pressure mercury lamp (for example, i-line) can be measured using a Fizeau interferometer type wavefront aberration measuring device disclosed in Japanese Patent No. 58-58. In this case, as shown in FIG. 12, laser light (for example, single mode of Ar laser light, wavelength 363.8 nm) having substantially the same wavelength as the exposure light is applied to the half prism 6.
The light enters the projection optical system 26 as the test optical system via the zero and the Fizeau surface 61 a of the Fizeau lens 61.
At this time, the light reflected by the Fizeau surface 61a becomes so-called reference light, and reaches an image sensor 62 such as a CCD via the Fizeau lens 61 and the half prism 60.

On the other hand, the light transmitted through the Fizeau surface 61a is
The light becomes so-called measurement light, and enters the reflective spherical surface 63 via the projection optical system 26. The measurement light reflected by the reflective spherical surface 63 reaches the CCD 62 via the projection optical system 26, the Fizeau lens 61, and the half prism 60. Thus, based on the interference between the reference light and the measurement light, the projection optical system 2
The wavefront aberration remaining in 6 is measured. Similarly, the wavefront aberration of a projection optical system using a KrF excimer laser light source can be measured using, for example, a Fizeau interferometer type wavefront aberration measuring device disclosed in Japanese Patent Application Laid-Open No. 10-38557.

For example, Japanese Patent Application Laid-Open No. 2000-97616
PDI (Phase Diffract) disclosed in
The wavefront aberration of a projection optical system using an ArF excimer laser light source can also be measured using an ion interferometer (phase diffraction interferometer) type wavefront aberration measuring device. In this case, as shown in FIG. 13, the exposure illumination light emitted from the light source 21 (not shown in FIG. 13) and transmitted through the illumination optical system 22 is transmitted to the first pinhole 71 positioned at the mask setting position. Incident. The spherical wave formed via the first pinhole 71 passes through the projection optical system 26 as an optical system to be detected and enters a grating (one-dimensional diffraction grating) 72.

[0107] The light transmitted through the grating 72 as it is
The next-order diffracted light enters a second pinhole (not shown) formed in the mask 73. On the other hand, the first-order diffracted light generated by the diffraction action of the grating 72 enters almost the center of an opening (not shown) formed in the mask 73. Second
The 0th-order diffracted light passing through the pinhole and the 1st-order diffracted light passing through the aperture are transmitted through the collimator lens 74 to the CC
An image sensor 75 such as D is reached. Thus, the spherical wave formed via the second pinhole is used as the reference wavefront, the wavefront of the first-order diffracted light that has passed through the aperture is used as the measurement wavefront, and the projection optical system 26 is used based on the interference between the reference wavefront and the measurement wavefront. Is measured.

Next, in the manufacturing method of the second embodiment, it is determined whether or not the wavefront aberration of the projection optical system measured in the aberration measuring step S16 falls within an allowable range (S17).
If it is determined in the determination step S17 that the wavefront aberration of the projection optical system falls within the allowable range (OK in FIG. 9), the manufacture of the projection optical system according to the second embodiment ends. On the other hand, if it is determined in the determination step S17 that the wavefront aberration of the projection optical system is not within the allowable range (NG in FIG. 9), the lens is moved along the optical axis AX to change the distance between the lenses. Adjustment of the interval to be performed and eccentricity adjustment of shifting or tilting the lens perpendicularly to the optical axis AX are performed (S18).

FIG. 14 is a diagram schematically showing the internal configuration of a projection optical system configured to enable adjustment of the interval and eccentricity. In FIG. 14, a common X corresponding to FIG.
An YZ coordinate system is used. As shown in FIG. 14, the lens barrel 30 includes a plurality of split lens barrels 11 to 16 and is supported by a frame of an exposure apparatus (not shown) via a flange 17 provided on the split lens barrel 16. The plurality of divided lens barrels 11 to 16 are stacked in the optical axis Ax direction. Then, of the plurality of divided barrels 11 to 16, the divided barrel 1
Lenses L1, P1, supported by 1, 12, 13
L1P2, L1P3, L1P4, L1P5, L1N1
Is a movable lens movable in the optical axis direction (Z direction) and tiltable about the XY directions.

Movable lenses L1P1, L1P2, L1P
The configuration of the split lens barrels 11, 12, and 13 holding 3, L1P4, L1P5, and L1N1 will be described. The split lens barrel 11 holds lens frames 21 and 22 holding the movable lenses L1P1 and L1P2, respectively, in a state of being laminated inside the split lens barrel 11, and is movable in the optical axis direction (Z direction) with respect to the split lens barrel 12. It is connected to the split lens barrel 12 so as to be tiltable about the XY directions. The split lens barrel 12 holds lens frames 23 and 24 holding the movable lenses L1P3 and L1P4, respectively, in a state of being stacked inside the split lens barrel 12, and is movable in the optical axis direction (Z direction) with respect to the split lens barrel 13 and The divided lens barrel 1 is tiltable about the XY directions as axes.
3 is connected. The divided lens barrel 13 is provided with a lens frame 2 that holds the movable lenses L1P5 and L1N1, respectively.
5 and 26 are held in a stacked state therein, and are movable in the optical axis direction (Z direction) with respect to the divided lens barrel 12 and XY
It is connected to the split lens barrel 14 so as to be tiltable about the direction.

Here, the split barrel 11 is driven by the actuator 81 attached to the split barrel 12, and the split barrel 12 is driven by the actuator 82 attached to the split barrel 13, and is mounted on the split barrel 14. The divided lens barrel 13 is driven by the actuator 83 thus set. These actuators 81 to 83 are provided at three positions of the split lens barrels 12 to 14, specifically, in the XY plane.
It is attached at every azimuth of 120 ° with the direction as an axis, whereby three positions in each of the divided lens barrels 11 to 13 move independently in the optical axis direction (Z direction).

Here, if the driving amounts at the three positions are the same in each of the divided lens barrels 11 to 13, the divided lens barrels 11 to 13 move with respect to the divided lens barrels 12 to 14 in the Z direction (light (In the axial direction), and if the driving amounts at the three positions are different, the divided lens barrels 11 to 13 tilt with respect to the divided lens barrels 12 to 14 in the XY directions as axes. .

As these actuators 81 to 83, piezoelectric elements having high precision, low heat generation, high rigidity, and high cleanliness can be used. The actuator 81
83 to 83 may be configured by a magnetostrictive actuator or a fluid pressure actuator instead of being configured by a piezoelectric element. Also,
In order to measure the amount of drive by these actuators, and hence the amount of movement of the divided lens barrels 11 to 13, a drive amount measuring device including, for example, an optical encoder is provided, and the movement of the divided lens barrels 11 to 13 and thus the movable lens L1P1 , L1
The movement of P2, L1P3, L1P4, L1P5, and L1N1 may be controlled in a closed loop.

The lenses L1N2 to L1N-L supported by the divided lens barrels 14 to 16 among the divided lens barrels 13 to 16 will now be described.
4P1 is a fixed lens. Split lens barrels 14-1 holding these fixed lenses L1N2-L4P1
6 will be described. The split lens barrel 14 includes a lens frame 31 that holds the fixed lenses L1N2 to L2P4, respectively.
37 and the spacers 41 to 43 are held in a stacked state inside the divided lens barrel 14, and are connected to the upper part of the divided lens barrel 15.

The split lens barrel 15 includes fixed lenses L2P5 to L2P.
The lens frames 50 to 55, the spacers 44 to 45, and the aperture stop AS, which respectively hold the 3P5, are held in a stacked state inside the split lens barrel 15, and are connected to the upper part of the split lens barrel 16. The divided lens barrel 16 has lens frames 61 to 61 that respectively hold the fixed lenses L3P4 to L4P1.
73 and the spacers 46 to 48 are held in a state of being stacked inside the divided lens barrel 16.

In the second embodiment, since a plurality of divided lens barrels 11 to 16 are provided, the distance between the divided lens barrels 11 to 16 can be adjusted during assembly of the projection optical system. By changing the thickness etc. of the member,
Eccentricity adjustment between divided lens barrels 11 to 16 (adjustment of positional relation in XY plane, adjustment of positional relation in tilt direction around XY direction) and adjustment of distance between divided lens barrels (adjustment of space in Z direction)
It can be performed. Note that such eccentricity / interval adjustment between the divided lens barrels is disclosed in JP-A-2001-56426.

In the above description, movement adjustment (interval adjustment) for moving the lens or the lens group along the optical axis Ax and tilt adjustment for tilting the lens or the lens group with respect to the optical axis Ax are limited. A shift adjustment is performed to shift the lens along a direction perpendicular to the optical axis Ax (a direction in the XY plane), and a rotation adjustment is performed to rotate the lens along a rotation direction about the optical axis Ax. You can also.

In the manufacturing method of the second embodiment, the wavefront aberration of the projection optical system whose lens has been adjusted by adjusting the distance or eccentricity is measured again (S16). Then, the aberration measurement step S1
It is determined again whether or not the wavefront aberration of the projection optical system measured again in 6 is within the allowable range (S17). If it is determined in the determination step S17 that the wavefront aberration of the projection optical system falls within the allowable range, the manufacture of the projection optical system ends. However, if it is determined in the determination step S17 that the wavefront aberration of the projection optical system is not within the allowable range, the lens adjustment step S18 and the aberration measurement step S16 are further performed until an OK determination is obtained in the determination step S17. repeat.

In the manufacturing method according to the second embodiment, the determination step S17 and the lens adjustment step S18 are provided after the aberration measurement step S16.
18 can be omitted. That is, after the projection optical system assembling step S15, the manufacturing method according to the second embodiment can be ended.

In the second embodiment, the case where the projection optical system according to the second embodiment having the same magnification is manufactured has been described as an example. However, the magnification of the projection optical system is not limited to the same magnification. For example, any of an enlargement magnification and a reduction magnification may be used. The manufacturing method of the second embodiment can be applied to a projection optical system having such an enlargement or reduction magnification as long as two or more aspherical surfaces having the same shape are provided in the projection optical system.
In the second embodiment, the case where the lens surface is an aspheric surface has been described as an example. However, the aspheric surface is not limited to the one provided on the lens surface, and may be, for example, a reflective surface.

As described above, according to the manufacturing method of the second embodiment, since the projection optical system has two or more sets of aspheric surfaces having the same shape, the measurement time for measuring these aspheric surfaces is reduced. And the time required for manufacturing the projection optical system can be reduced, and the cost for manufacturing the projection optical system (manufacturing cost of the manufacturing apparatus, manufacturing cost of the projection optical system) can be sufficiently suppressed.

In the above embodiment, the i-line (365)
Although an example using an ultra-high pressure mercury lamp that supplies exposure light of (nm) as a light source has been described, the wavelength of exposure light is not limited to i-line. For example, using an ultra-high pressure mercury lamp as a light source, g
Only the line (436 nm), only the h line (405 nm), g line and h line, h line and i line, or g line, h line and i line may be used as the exposure light.

A KrF excimer laser for supplying 248 nm light is used as a light source, and an Ar for supplying 193 nm light.
rF excimer laser may be used F ₂ laser etc. for supplying light of 157nm as a light source. Here, in the case where a KrF excimer laser is used as a light source, when the exposure light is narrowed, quartz glass is used as the refractive optical element in the projection optical system, and the exposure light is not narrowed in order to increase the amount of exposure light. Sometimes quartz glass and fluorite are used as refractive optical elements in the projection optical system. When an ArF excimer laser is used as a light source, quartz glass and fluorite are used as refractive optical elements in the projection optical system. When an F ₂ laser is used as a light source,
Fluorite is used as the refractive optical element in the projection optical system.

In the above-described embodiment, the projection exposure apparatus used in the lithography process of manufacturing a display device such as a liquid crystal display element or a plasma display panel (PDP) has been described. The present invention is not limited to the apparatus, and can be applied to, for example, semiconductor device manufacturing, photomask manufacturing, magnetic head manufacturing, and printed wiring board manufacturing. Note that a projection exposure apparatus for manufacturing a semiconductor device uses a wafer as a work, a projection exposure apparatus for manufacturing a display device uses a glass substrate as a work, and a projection exposure apparatus for manufacturing a photomask uses a glass substrate or a silicon substrate as a work. In a projection exposure apparatus for manufacturing a magnetic head, a bar-shaped substrate called a row bar is used as a work, and in a projection exposure apparatus for manufacturing a printed wiring board, a resin substrate such as an epoxy resin is used as a work W. Further, the present invention is also applicable to a projection exposure apparatus using a strip film as at least one of a substrate and a work.
Such a projection exposure apparatus is, for example, a TAB (Tape Automated).
2. Description of the Related Art There is known a film exposure apparatus used for manufacturing a film circuit board used for mounting an electronic component of an ated bonding type.

In the above embodiment, the batch exposure system for collectively transferring the pattern image on the reticle (mask) to a predetermined shot area on the substrate is employed. -An and scan type projection exposure apparatus or a stitching and slit scan type exposure apparatus may be used. Where step and
A scan type projection exposure apparatus scans a reticle and a substrate in a predetermined direction synchronously with respect to an illumination area of a predetermined shape on a reticle (mask), so that the reticle is projected onto one shot area on the substrate. The pattern images are sequentially transferred. In such a step-and-scan type exposure apparatus, it is possible to expose a reticle pattern to an area on a substrate which is wider than the exposure field of the projection optical system.

In the stitching and slit scan type exposure apparatus, the reticle and the substrate are synchronously scanned in a predetermined first direction relative to an illumination area of a predetermined shape on the reticle (mask). As a result, the first column region on the substrate is exposed. Thereafter, the reticle is replaced, or the reticle is moved by a predetermined amount along a second direction orthogonal to the first direction of the illumination area, and the substrate is conjugated with the second direction of the illumination area. Sideways. Then, the reticle and the substrate are synchronously scanned in the first direction again with respect to the illumination region of the predetermined shape on the reticle, thereby exposing the region on the second column on the substrate. In such a stitching and slit scan type exposure apparatus, a reticle pattern can be exposed to a region on a substrate wider than the exposure field of the projection optical system. Note that such a stitching and slit scan type exposure apparatus is disclosed in US Pat.
Nos. 4,771,304, JP-A-8-330220, and JP-A-10-284408.

In the projection exposure apparatus of the above embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined circuit pattern on a plate (glass substrate). Hereinafter, description will be made with reference to the flowchart of FIG. 8, in a pattern forming step 401, a so-called optical lithography step of transferring and exposing a pattern of a reticle (mask) to a photosensitive substrate (a glass substrate coated with a resist) using the exposure apparatus of the present embodiment is performed. Is done. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate is subjected to a development process, an etching process, a reticle peeling process and the like to form a predetermined pattern on the substrate,
The process proceeds to the next color filter forming step 402.

Next, in the color filter forming step 402, three colors corresponding to R (Red), G (Green), and B (Blue)
A set of one dot forms a color filter in which many are arranged in a matrix. Then, after the color filter forming step 402, a cell assembling step 403 is performed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like. In the cell assembling step 403, for example, a liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, and a liquid crystal panel (liquid crystal cell) is formed. ) To manufacture.

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

[0095]

As described above, according to the projection optical system of the present invention, a wide projection field of view and a high resolving power can be secured.
Good optical performance with excellent flatness of the image plane and relatively little change in the focal position due to temperature change can be achieved. Therefore, according to the exposure apparatus and the exposure method of the present invention, favorable exposure can be performed using the projection optical system of the present invention having good optical performance without increasing the cost of the apparatus and materials. Further, according to the present invention, a good microdevice with a large area can be manufactured by favorable exposure using the exposure apparatus of the present invention. Further, according to the method for manufacturing a projection optical system of the present invention, a projection optical system having high optical performance can be obtained, but the manufacturing time can be shortened without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of an exposure apparatus including a projection optical system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a lens configuration of a projection optical system according to a first example of the present embodiment.

FIG. 3 is a diagram illustrating spherical aberration, astigmatism, and distortion of the projection optical system in the first example.

FIG. 4 is a diagram showing coma aberration of the projection optical system in the first example.

FIG. 5 is a diagram showing a lens configuration of a projection optical system according to Example 2 of the present embodiment.

FIG. 6 is a diagram illustrating spherical aberration, astigmatism, and distortion of a projection optical system in a second example.

FIG. 7 is a diagram illustrating coma aberration of a projection optical system in a second example.

FIG. 8 is a flowchart of a method for obtaining a liquid crystal display element as a micro device by forming a predetermined pattern on a plate using the exposure apparatus of the present embodiment.

FIG. 9 is a flowchart showing a manufacturing flow of a method for manufacturing a projection optical system according to the second embodiment of the present invention.

FIG. 10 is a diagram schematically showing a configuration of an interferometer device for measuring an absolute value of a refractive index and a refractive index distribution of a block glass material on which each lens is to be formed.

FIG. 11 is a diagram schematically showing a configuration of an interferometer apparatus suitable for measuring a surface shape of a spherical lens having a spherical design value.

FIG. 12 is a diagram schematically illustrating a configuration of a Fizeau interferometer type wavefront aberration measuring device that measures a wavefront aberration of a projection optical system using an i-line lamp light source.

FIG. 13 is a diagram schematically showing a configuration of a PDI type wavefront aberration measuring device for measuring a wavefront aberration of a projection optical system using an ArF excimer laser light source.

FIG. 14 is a diagram schematically showing an internal configuration of a projection optical system configured to enable interval adjustment and eccentricity adjustment.

[Explanation of symbols]

 Reference Signs List 1 light source 2 elliptical mirror 4 collimating lens 5 wavelength selection filter 6 fly-eye lens 7 aperture stop 8 condenser optical system M mask PL projection optical system P plate G1 first partial optical system G2 second partial optical system AS aperture stop

Continued on the front page F term (reference) 2H087 KA21 LA01 PA15 PA19 PB20 QA03 QA06 QA17 QA19 QA21 QA25 QA37 QA39 QA41 QA45 RA05 RA12 RA13 RA32 5F046 BA03 CB12 CB25

Claims (13)

[Claims] An image of a pattern formed on a first surface is formed on a second surface.
In a projection optical system for projecting onto a surface at substantially the same magnification, the projection optical system includes, in order from the first surface side, a first partial optical system and a first pupil plane of the projection optical system. A partial optical system and a second partial optical system configured substantially symmetrically, wherein the first partial optical system includes a first pair of concave refraction surfaces arranged so as to face each other; A projection optical system, comprising: a second set of a pair of concave refraction surfaces disposed so as to face each other in an optical path between a first set of a pair of concave refraction surfaces. 2. The first partial optical system includes: a first negative lens having a concave surface facing the second surface in order from the first surface;
A second negative lens having a concave surface facing the second surface;
The projection optical system according to claim 1, further comprising a third negative lens having a concave surface facing the surface, and a fourth negative lens having a concave surface facing the first surface. 3. The first partial optical system includes, in order from the first surface side, a first positive lens group having a positive refractive power, a first negative lens group having a negative refractive power, and a positive refraction. A second positive lens group having a power, wherein the first negative lens group includes, in order from the first surface side, a first negative lens having a concave surface facing the second surface side, and the second surface side A second negative lens having a concave surface facing the first surface, a third negative lens having a concave surface facing the first surface, and a fourth negative lens having a concave surface facing the first surface.
When a focal length of the first partial optical system is F ₁ and a focal length of the first negative lens unit is f _{1N, the following condition} is satisfied: −0.4 <f _1N / F ₁ <0 The projection optical system according to claim 1, wherein a condition is satisfied. 4. An image of a pattern formed on a first surface is formed on a second surface.
In a projection optical system for projecting onto a surface at substantially the same magnification, the projection optical system includes, in order from the first surface side, a first partial optical system and a first pupil plane of the projection optical system. A second partial optical system configured substantially symmetrically with the partial optical system, wherein the first partial optical system includes, in order from the first surface side, a first positive lens group having a positive refractive power; A first negative lens group having a positive refractive power and a second positive lens group having a positive refractive power. The refractive index n of the optical element with respect to the illumination light supplied to the projection optical system with respect to the ambient temperature T When the rate of change is represented by dn / dT, at least one of the second positive lens groups
The projection optical system, wherein the two negative lenses satisfy a condition of dn / dT <0. 5. The projection optical system according to claim 4, wherein at least one positive lens constituting the second positive lens group satisfies a condition of dn / dT> 0. 6. An image of a pattern formed on a first surface is formed on a second surface.
In a projection optical system that projects onto a surface at substantially the same magnification, the projection optical system has an aspheric surface, a distance along the optical axis between the first surface and the second surface is L, and A projection optical system characterized by satisfying a condition of 0.035 <LA / L <0.3, where LA is a distance along the optical axis from one surface to the aspheric surface. 7. The projection optical system has a first aspherical surface and a second aspherical surface symmetrically arranged with respect to a pupil plane of the projection optical system. When a distance along the optical axis along the optical axis is L and a distance along the optical axis from the first surface to the first aspheric surface is LA, the condition of 0.035 <LA / L <0.3 is satisfied. The projection optical system according to claim 6, wherein: 8. A projection optical system for lithography for projecting an image of a mask pattern formed on a first surface onto a second surface on which a photosensitive substrate is arranged, wherein the projection optical system has a first aspherical surface. And a second aspherical surface, wherein the first aspherical surface and the second aspherical surface have the same shape as each other. 9. A method of manufacturing a projection optical system for lithography for projecting an image of a mask pattern formed on a first surface onto a second surface on which a photosensitive substrate is arranged, wherein a plurality of optical elements are prepared. A step of forming an aspheric surface of a predetermined shape on at least two of the plurality of prepared optical elements to obtain at least a first aspheric optical element and a second aspheric optical element; A third step of inspecting the surface shapes of the first and second aspherical optical elements; and a fourth step of arranging the optical elements along a predetermined optical axis. Production method. 10. A projection optical system manufactured by the manufacturing method according to claim 9. 11. The projection optical system according to claim 1, further comprising: an illumination optical system configured to illuminate a mask set on the first surface, wherein the illumination optical system illuminates a mask set on the first surface. An exposure apparatus that exposes a pattern formed on the mask to a photosensitive substrate set on the second surface via a projection optical system. 12. An exposure step of exposing the pattern of the mask to the photosensitive substrate using the exposure apparatus according to claim 11, and a developing step of developing the photosensitive substrate exposed through the exposure step. And a method for manufacturing a microdevice. 13. An illuminating step of illuminating a mask on which a predetermined pattern is formed, and using the projection optical system according to claim 1 to illuminate the first surface. An exposing step of exposing the set mask pattern to the photosensitive substrate set on the second surface.