JP2000249917A - Projection optical system, production of projection optical system, production of illumination optical system and production of exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure necessary optical performance even in the case of using one or plural lenses whose refracting index is non-uniform by using one or plural lenses whose refractive index in the radial direction with an optical axis as center is non-uniform and providing one or plural aspherical surfaces for compensating aberration caused by the refractive index of the lens. SOLUTION: The aberration deteriorated by use in a state where refractive index distribution is non-uniform is compensated by the aspherical surface. A 1st lens group having positive refractive power mainly contributes to the compensation of distortion aberration while maintaining telecentricity on an object side. Namely, by causing the positive distortion aberration in the 1st lens group, the balance thereof with the negative distortion aberration caused in 2nd and 3rd lens groups is kept. The 2nd and the 4th lens groups having negative refractive power mainly contribute to the correction of Petzval's sum. Furthermore, the 2nd and the 4th lens groups form an inverted Galilean system, and contribute to the securement of the back focus of a projection optical system in addition to the adjustment of magnification. Then, 5th and 6th lens groups having positive refractive power restrain the occurrence of the distortion aberration and contribute to the restraint of the occurrence of spherical aberration.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical system using one or a plurality of optical members (lenses and the like) having non-uniform optical characteristics (for example, a non-uniform refractive index in a radial direction around the optical axis). More particularly, the present invention relates to a projection optical system for projecting and transferring a pattern on a projection original onto a photosensitive substrate, or an illumination optical system for illuminating the projection original. Further, the present invention provides a method for manufacturing a projection optical system, a method for manufacturing an illumination optical system, a method for manufacturing an exposure apparatus, an exposure method, and a method for manufacturing a micro device. The present invention also relates to a method for producing the same.

[0002]

2. Description of the Related Art An exposure apparatus is used as one process for manufacturing a semiconductor circuit element, a liquid crystal display element, and the like. This exposure apparatus is an apparatus for projecting and transferring a pattern on a projection original such as a reticle and a mask onto a photosensitive substrate such as a wafer or a glass plate via a projection optical system. In order to project a fine mask pattern onto a photosensitive substrate, a projection optical system is required to have a very high optical performance of high resolution and close to no aberration.

Therefore, in order to correct aberrations caused by assembly and manufacturing errors of the projection optical system, it is necessary to change the thickness of a washer inside a lens barrel for holding an optical element such as a lens or to resharp the lens surface. Is being done. On the other hand, in order to achieve higher precision and larger NA of the projection optical system, non-uniformity of the refractive index inside the lens has become a non-negligible factor. The refractive index non-uniformity cannot be ignored.

[0004] The non-uniformity of the refractive index inside the lens cannot be corrected by changing the thickness of the washer or resharpening the lens surface. Therefore, a lens cannot be originally manufactured from a lens ingot that does not fall within the use tolerance.

[0005]

However, if the ingot, whose refractive index uniformity does not fall within the tolerance, is discarded, the production efficiency of the lens is reduced, and therefore the production efficiency of the projection optical system is reduced. Will be reduced. This problem is deeply related not only to the production of the projection optical system but also to the production of the illumination optical system or the production of various devices such as an inspection device requiring high optical performance.

Accordingly, the present invention provides various types of optical systems such as a projection optical system using one or more optical members (lenses and the like) having a non-uniform refractive index and capable of securing necessary optical performance. It is an object to provide a method for manufacturing a system and a method for manufacturing various devices.

[0007]

SUMMARY OF THE INVENTION Even in a lens having a non-uniform refractive index, in many cases, the non-uniformity of the refractive index is distributed in a radial direction and uniform in a circumferential direction. There are many. The present invention has solved the above problem by focusing on this point. That is, the present invention uses one or more lenses having a non-uniform refractive index in a radial direction around the optical axis, and An optical system having one or more aspherical surfaces for correcting aberration caused by the non-uniformity of the refractive index. In this case, as the optical system,
For example, it is preferable to use a projection optical system that projects and transfers the pattern on the projection original onto the photosensitive substrate, or an illumination optical system that illuminates the original for transfer.

As described above, according to the present invention, the aberration deteriorated by the use of a lens having a non-uniform refractive index distribution is corrected by employing an aspherical surface. In the present invention, when the maximum value of the refractive index is nmax and the minimum value is nmin for each lens having a non-uniform refractive index,

[0009]

It is preferable that nmax−nmin> 1 × 10 ⁻⁷ ‥‥ (1). That is, when the expression (1) is satisfied, the refractive index of the lens is assumed to be non-uniform,
It is preferable that the aberration caused by this is corrected by an aspherical surface.

Conversely, the degree of non-uniformity of the refractive index is
When the value is outside the range of the expression (1), it can be said that the refractive index distribution of the lens is substantially uniform. Therefore, even if an aberration caused by such a lens is to be corrected by an aspherical surface, the difference (amount of sag) between the aspherical surface and the spherical surface becomes extremely small, and there is no point in introducing an aspherical surface. In the projection optical system of the present invention, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, It is preferable that the second lens group include a fourth lens group having a positive refractive power, a fifth lens group having a positive refractive power, and a sixth lens group having a positive refractive power.

The first lens group having a positive refractive power mainly contributes to correction of distortion while maintaining telecentricity on the object side. That is, by generating positive distortion in the first lens group, the balance with negative distortion generated in the second and fourth lens groups is maintained.
The second and fourth lens groups having negative refractive power mainly contribute to correction of Petzval sum. Further, the second and third lens groups form an inverse Galileo system, which not only adjusts the magnification but also contributes to securing the back focus of the projection optical system.

The fifth and sixth lens units having a positive refractive power contribute to suppressing the occurrence of distortion and, in particular, the occurrence of spherical aberration. Next, when the projection optical system has the above-described six-group configuration,

[0013]

0.04 <| f ₄ /L|<0.2 (2) 0.02 <f ₅ /L<0.9 (3) 0.02 <f ₆ / L <1 0.5 (4) D ₅₆ /L<0.3 {5} 0.5 <D ₆ / R ₆ <1.5 { ₆ }

Where f _{i is} the focal length of the ith lens group (i
= 4,5,6) L: distance on the optical axis from the object plane to the image plane D ₅₆ : distance between the fifth and sixth lens groups D ₆ : lens surface of the sixth lens group closest to the object Distance on the optical axis from to the image plane R ₆ : radius of curvature of the lens surface closest to the object side in the sixth lens group.

Condition (2) relates to the balance between spherical aberration and coma. If the lower limit of condition (2) is exceeded, correction of spherical aberration becomes difficult, and a lens having a non-uniform refractive index. It becomes difficult to use. Conversely, if the value exceeds the upper limit, coma occurs, and it becomes difficult to use a lens having a non-uniform refractive index. Conditional expression (3) relates to the balance of spherical aberration, distortion, and Petzval sum. If the lower limit of conditional expression (3) is exceeded, negative distortion and negative spherical aberration increase, and the refractive index further increases. It becomes difficult to use an uneven lens. Conversely, if the value exceeds the upper limit, it becomes difficult to correct the Petzval sum satisfactorily, and it becomes difficult to use a lens having a non-uniform refractive index.

Condition (4) relates to the balance between higher order spherical aberration and negative distortion. If the lower limit of condition (4) is exceeded, negative distortion and negative spherical aberration increase. In addition, it becomes more difficult to use a lens having a non-uniform refractive index. Conversely, if the upper limit is exceeded, higher-order spherical aberrations will occur, and light rays will pass through the lens at an acute angle, making it difficult to use a lens with a non-uniform refractive index.

If the upper limit of conditional expression (5) is exceeded,
Since the lens distance between the fifth lens group and the sixth lens group increases, the positive distortion is weakened, and the effect of the light rays being emitted at an acute angle generates higher-order spherical aberration and the like, which makes correction difficult. Become. If the lower limit of conditional expression (6) is exceeded, the positive refractive power of the lens surface closest to the object side in the sixth lens group will be too strong, negative distortion and coma will increase, and the refractive index will also increase. It becomes difficult to use non-uniform lenses. Conversely, if the value exceeds the upper limit, coma aberration is large, and it becomes difficult to use a lens having a non-uniform refractive index.

Next, when the projection optical system has the above-described six-group configuration, the lens surfaces of the lenses belonging to the first lens group are:
At least one of the lens surfaces of the lens disposed closest to the first lens group in the second lens group is formed by an aspheric surface; and

[0019]

It is preferable that the following condition is satisfied: | Df−Db |> 0.1 条件 (7) Where Df = Rf · sinwf · λ / (NA · Ymax) Db = Rb · sinwb · λ / (NA · Ymax) Rf: radius of the wavefront shape with respect to the maximum image height in a system in which an aspheric surface is replaced by a spherical surface ( Wf: incident azimuth angle of the wavefront shape with respect to the maximum image height in a system in which the aspherical surface is replaced with a spherical surface Rb: radius of the wavefront shape with respect to the maximum image height in the system employing the aspherical surface (Absolute amount of image plane incident angle) wb: incident azimuth angle of the wavefront shape with respect to the maximum image height in a system employing an aspherical surface λ: used wavelength NA: maximum image side numerical aperture Ymax: maximum image height

The conditional expression (7) is a conditional expression for efficiently correcting various aberrations caused by the use of a lens having a non-uniform refractive index, and in particular, a lens belonging to the first lens group. A condition for contributing to the correction of distortion by making at least one of the lens surface of the second lens group and the lens surface of the lens closest to the first lens group side of the second lens group an aspheric surface. It is an expression.

If the lower limit of conditional expression (7) is not reached, the distortion which has been deteriorated by the use of a lens having a non-uniform refractive index has not actually deteriorated so much. There is no point in introducing a spherical surface, or the distortion has deteriorated to some extent, but the correction has not been made efficiently, and the difference (sag amount) between the aspherical surface and the spherical surface is very small. There is no point in introducing.

When the projection optical system has the above-described six-group configuration, the lens surfaces of the lenses belonging to the second lens group include:
At least one of the lens surfaces of the lens disposed closest to the second lens group in the third lens group is formed by an aspheric surface; and

[0023]

| Af−Ab |> 0.02 ‥‥ (8) It is preferable to satisfy the following condition. Where Af = (4Rf ⁴ -3Rf ² ) cos2wf · λ
/ (NA · Ymax) Ab = (4Rb ⁴ -3Rb ² ) cos2wb · λ / (N
A · Ymax).

The above-mentioned conditional expression (8) is a conditional expression for efficiently correcting various aberrations deteriorated by using a lens having a non-uniform refractive index, and in particular, a lens belonging to the second lens group. By making at least one of the lens surfaces of the first lens unit and the lens surface of the lens disposed closest to the second lens unit side of the third lens unit into an aspheric surface, it contributes to the correction of the fifth-order astigmatic difference. It is a conditional expression for performing.

If the lower limit of conditional expression (8) is not reached, the astigmatism which has been deteriorated by the use of a lens having a non-uniform refractive index has not actually deteriorated so much. There is no point in introducing an aspherical surface, or the astigmatic difference has deteriorated to some extent, but the correction has not been made efficiently, and the difference between the aspherical surface and the spherical surface (sag amount) is very small. There is no point in introducing an aspheric surface.

When the projection optical system has the above-described six-group configuration, at least one of the lens surfaces of the lenses belonging to the third lens group and the fourth lens group is formed by an aspheric surface, and

[0027]

It is preferable that the following condition is satisfied: | Cf−Cb |> 0.06 ‥‥ (9) ^{However, Cf = (10Rf 5 -12Rf 3} + 3Rf) si
nwf × λ / (NA · Ymax) Cb = (10Rb ⁵ −12Rb ³ + 3Rb) sinwb
× λ / (NA · Ymax).

The above-mentioned conditional expression (9) is a conditional expression for efficiently correcting various aberrations caused by the use of a lens having a non-uniform refractive index. This is a conditional expression for contributing to correction of coma aberration by making at least one of the lens surfaces of the lenses belonging to the lens group an aspheric surface. When the value goes below the lower limit of conditional expression (9), the aspherical surface is introduced at the above position because the coma aberration deteriorated by using the lens having the non-uniform refractive index is not actually deteriorated much. Or the coma aberration has deteriorated to some extent, but the correction has not been made efficiently and the difference between the aspherical surface and the spherical surface (the amount of sag) is very small. meaningless.

When the projection optical system has the six-group configuration, at least one of the lens surfaces of the lenses belonging to the fifth lens group and the sixth lens group is formed by an aspherical surface.

[0030]

It is preferable that the following condition is satisfied: | Sf−Sb |> 0.02 ‥‥ (10) However, Sf = (20Rf ⁶ -30Rf ⁴ + 12Rf ² −
1) · λ / (NA · Ymax) Sb = (20Rb ⁶ −30Rb ⁴ + 12Rb ² −1) ·
λ / (NA · Ymax).

The above-mentioned conditional expression (10) satisfies various aberrations which are deteriorated by using a lens having a non-uniform refractive index.
This is a conditional expression for efficient correction. In particular, by correcting at least one of the lens surfaces of the lenses belonging to the fifth lens unit and the sixth lens unit to an aspheric surface, the fifth-order spherical aberration is corrected. Is a conditional expression for contributing to. When the value goes below the lower limit of conditional expression (10), the spherical aberration deteriorated by using the lens having the non-uniform refractive index is not actually deteriorated so much. Or the spherical aberration has deteriorated to some extent, but the correction has not been made efficiently and the difference between the aspheric surface and the spherical surface (the amount of sag) is very small. meaningless.

According to a still further aspect of the present invention, there is provided a method of manufacturing a projection optical system for projecting an image of a predetermined pattern formed on a projection master onto a photosensitive substrate. A first step of measuring non-uniformity; a second step of calculating an aberration generated by a refractive optical member having a non-uniform refractive index; and an aspherical shape capable of correcting the aberration calculated in the second step And a fourth step of giving the aspherical shape calculated in the third step to the refractive optical member.
And a fifth step of assembling the refractive optical member.

At this time, the non-uniformity of the refractive index is a refractive index distribution in a radial direction about the optical axis, and the aspherical shape is a rotationally symmetric shape about the optical axis. preferable. According to a tenth aspect of the present invention, in a method of manufacturing a projection optical system for projecting an image of a predetermined pattern formed on a projection original onto a photosensitive substrate, the refractive indices of the plurality of refractive optical members may be non-uniform. A first measuring step of measuring the property; a processing step of processing the plurality of refractive optical members having passed through the first measuring step; and a second step of measuring the shapes of the processing surfaces of the plurality of refractive optical members having passed through the processing step. Two measuring steps;
An assembling step of assembling the projection optical system using the plurality of refractive optical members having undergone the measuring step; a third measuring step of measuring remaining unnecessary optical characteristics of the projection optical system having undergone the assembling step; In order to correct the remaining unnecessary optical characteristics of the optical system, the first, second and third
A calculating step of calculating a correction surface shape for at least one processing surface of the plurality of refractive optical members based on each measurement information obtained in the measurement step; and a calculation step for calculating the correction surface shape obtained in the calculation step. A reworking step of reworking at least one processing surface of the plurality of refraction optical members based on the information; a refraction optical member reworked by the reworking step; and a refraction optical member processed in the processing step. Or a finishing step of completing the projection optical system by using a refraction optical member reprocessed in the reprocessing step.

According to a fifteenth aspect of the present invention, there is provided a method of manufacturing a projection optical system for projecting an image of a predetermined pattern formed on a projection original onto a photosensitive substrate. A first measuring step of measuring non-uniformity of;
A processing step of processing the plurality of refractive optical members after the first measuring step; a second measuring step of measuring the shapes of processing surfaces of the plurality of refractive optical members after the processing step; and the plurality of refractive optics In order to correct the remaining unnecessary optical characteristics of the projection optical system caused by the non-uniformity of the refractive index of the member and the processing error of the processing surfaces of the plurality of refractive optical members, the first and second optical characteristics are corrected. A calculating step of calculating a correction surface shape for at least one processed surface of the plurality of refractive optical members based on each measurement information obtained in the measurement step; and a calculation step for calculating the correction surface shape obtained in the calculation step. A reworking step of reworking at least one processing surface of the plurality of refraction optical members based on the information; the refraction optical member reworked by the reworking step; and the refraction optical member processed by the processing step It is a manufacturing method of a projection optical system which comprises a; finishing step to complete the projection optical system by using the refractive optical member was reworked or by the rework process used.

At this time, in the above-described method of manufacturing each projection optical system, it is preferable that the calculating step further calculates a correction surface shape using optical design information of the projection optical system. Further, the calculating step may further calculate a correction surface shape using the assembly information in the assembling step. Further, in the above-described method of manufacturing each projection optical system,
It is preferable that the finishing step includes an adjusting step of adjusting at least one position of the plurality of refractive optical members.

Further, according to the present invention, there is provided a projection optical system manufactured by the above-described method for manufacturing a projection optical system, and an illumination optical system for illuminating the projection original. A step of preparing; illuminating a projection original by the illumination optical system, and projecting an image of a predetermined pattern formed on the projection original by the projection optical system onto a photosensitive substrate. And a step of setting the projection optical system at a predetermined position.

According to a twentieth aspect of the present invention, there is provided a method of manufacturing an illumination optical system for illuminating the original in order to expose an image of a predetermined pattern formed on the original onto a photosensitive substrate. A first measuring step of measuring the non-uniformity of the refractive index of the member; a processing step of processing the plurality of refractive optical members having passed through the first measuring step; and a processing of the plurality of refractive optical members having passed through the processing step The second to measure the shape of the surface
A measuring step; an assembling step of assembling the illumination optical system using the plurality of refractive optical members having passed through the second measuring step; and a second step of measuring remaining unnecessary optical characteristics of the illumination optical system having passed through the assembling step. Three measuring steps; based on each measurement information obtained in the first, second, and third measuring steps, in order to correct remaining unnecessary optical characteristics of the illumination optical system, A calculating step of calculating a corrected surface shape for at least one processed surface of the member; re-processing at least one processed surface of the plurality of refractive optical members based on the information on the corrected surface shape obtained in the calculating step. A reworking step of processing; using the refraction optical member reworked in the reworking step and the refraction optical member processed in the processing step, or reworked in the reworking step It is a manufacturing method of an illumination optical system which comprises a; finishing step to complete the illumination optical system by that the use of folding optical element.

According to a twenty-first aspect of the present invention, there is provided a method of manufacturing an illumination optical system for illuminating the original in order to expose an image of a predetermined pattern formed on the original onto a photosensitive substrate. A first measuring step of measuring the non-uniformity of the refractive index of the refractive optical member; a processing step of processing the plurality of refractive optical members having passed through the first measuring step; and the plurality of refractive optical members having passed through the processing step A second measuring step of measuring the shape of the processing surface of the above; and the illumination optical system generated due to non-uniformity of the refractive index of the plurality of refractive optical members and a processing error of the processing surface of the plurality of refractive optical members. In order to correct the remaining unnecessary optical characteristics, based on each measurement information obtained in the first and second measurement steps, the correction surface shape of at least one processing surface of the plurality of refractive optical members is changed. Calculation process to calculate Reprocessing process based on the information about the correction-sectional shape obtained in the calculating step, reworking at least one working surface of the plurality of refractive optical member;
By using the refractive optical member reprocessed in the reprocessing step and the refractive optical member processed in the processing step, or by using the refractive optical member reprocessed in the reprocessing step, the illumination optical system And a finishing step of completing the illumination optical system.

According to a twentieth or a twenty-first aspect of the present invention, there is provided a method of preparing an illumination optical system manufactured by the above-described method of manufacturing each illumination optical system; and projecting an image of the pattern of the original onto a photosensitive substrate. Preparing a projection optical system for illuminating the original with the illumination optical system, and projecting an image of a predetermined pattern formed on the original by the projection optical system onto a photosensitive substrate. Installing the illumination optical system and the projection optical system at predetermined positions.

According to a twenty-third aspect of the present invention, there is provided a preparation step of preparing an exposure apparatus manufactured by the above-described method of manufacturing an exposure apparatus; an illumination step of illuminating the original using the illumination optical system; A micro device comprising: an exposure step of exposing an image of the pattern of the original to the photosensitive substrate using an optical system; and a development step of developing the photosensitive substrate exposed in the exposure step. It is a manufacturing method of.

[0041]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of a projection optical system according to the present invention, in which a pattern on a reticle R is projected onto a wafer W and transferred. The projection optical system includes, in order from the reticle R side, a first lens group G1 having a positive refractive power;
A second lens group G2 having a negative refractive power, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a negative refractive power, a fifth lens group G5 having a positive refractive power, and a positive And a sixth lens group G6 having the following refractive power.

Table 1 below shows data of this embodiment. Table 1
In [Lens Specifications], the first column No is the number of each lens surface from the reticle R side, the second column r is the radius of curvature of each lens surface,
The third column d indicates the distance on the optical axis from each lens surface to the next lens surface, and the fourth column indicates the number of a lens (blank is air) satisfying each lens surface from the next lens surface. The glass material of all lenses is synthetic quartz (SiO ₂ ) and the wavelength used (λ
= 248.4 nm), the refractive index n of the synthetic quartz is n = 1.508390.

In this embodiment, a plurality of lenses having a non-uniform refractive index in the radial direction around the optical axis are used.
In this case, the refractive index n of the lens is expressed as follows: n = N ₀ + N ₂ · r ² + N ₄ · r ⁴ + N ₆ · r ⁶ N _i : coefficient (i = _{0, 2} , ₄ , ₆ ) r: radius Can be. In [Refractive index non-uniformity] of Table 1, the number of the lens whose refractive index is non-uniform, and the coefficients N ₂ , N ₄ ,
Shows the N _6. However, for any lens, N0 = 1.508390.

In this embodiment, a plurality of aspherical surfaces are arranged in order to correct aberrations caused by non-uniformity of the refractive index of the lens. The aspheric shape is

[0045]

(Equation 7)

S (y): distance in the optical axis direction from the aspheric surface to the tangent plane at a height y from the optical axis r: paraxial radius of curvature κ: conical constant A, B, C, D: aspherical surface coefficient Can be represented. In [Aspherical surface data] in Table 1, the number No of the lens surface employing the aspherical surface, the aspherical surface coefficient A,
B, C, and D are shown. However, for any lens,
The conic constant κ is zero.

In Table 1, [Values for Conditional Expressions] show the values of the parameters in the conditional expressions (1) to (10).

[0048]

[Table 1] [Main specifications] Image side maximum numerical aperture NA = 0.4 Working wavelength λ = 248.4 nm L = 1300 mm [Optical member specifications] Nor d 0 ∞ 110.813980 R 1 -2567.05600 15.000000 L1 2 -256.49158 1.000000 3 192.65125 48.637020 L2 4 -861.44884 1.000000 5 302.52998 38.776880 L3 6 128.72273 16.572980 7 -353.74446 15.000000 L4 8 150.13109 14.747380 9 -331.08095 48.270620 L5 10 250.11152 26.534840 11 -114.88270 16.523770.6120 -573.62319 15.86 12.120 -573.62319 16.86 L8 16 -273.30318 2.629440 17 890.96746 57.543860 L9 18 -316.75427 29.181020 19 305.13587 75.710690 L10 20 -824.24930 9.082970 21 187.59132 44.228020 L11 22 645.89151 9.034930 23 916.25554 18.094670 L12 24 123.000023.78 1370 24. 134.17246 11.979610 29 -153.57992 50.555440 L15 30 -193.60916 8.435690 31-4.831700 AS 32 -1546.15700 29.450510 L1 6 33 -338.02569 1.000000 34 177.03486 16.082190 L17 35 170.58898 19.345880 36 420.54438 72.696780 L18 37 -612.39548 22.671210 38 312.58481 42. 17.236910 L23 47 121.46206 5.875290 48 125.09232 20.123380 L24 49 1848.46800 15.000120 50 ∞ W [ refractive index _{inhomogeneity] L2 N 2 = -0.4648 × 10} -6 N 4 = 0.2366 × 10 -11 N 6 = -0.2573 × 10 -14 L3 N ₂ = 0.8423 × 10 ^-6 N ₄ = -0.8087 × 10 ^-11 N ₆ = 0.1387 × 10 ^-13 L5 N ₂ = 0.9916 × 10 ^-7 N ₄ = -0.1008 × 10 ^-9 N ₆ = -0.1815 × 10 _{^{-13 L9 N 2 = -0.2698 × 10}} -6 N 4 = -0.2239 × 10 -10 N 6 = 0.3818 × 10 -15 L10 N 2 = 0.1714 × 10 -6 N 4 = 0.1928 × 10 -10 N 6 = - 0.3714 × 10 ^-15 L15 N ₂ = -0.8066 × 10 ^-7 N ₄ = 0.2175 × 10 ^-12 N ₆ = 0.4227 × 10 ^-15 L18 N ₂ = 0.3448 × 10 ^{-7 _{N 4 = -0.2343 × 10 -11 N}} 6 = -0.2561 × 10 -15 L19 N 2 = 0.1132 × 10 -6 N 4 = -0.8997 × 10 -11 N 6 = 0.7126 × 10 -15 L21 N 2 = -0.1266 × 10 ⁻⁶ N ₄ = 0.5471 × 10 ⁻¹⁰ N ₆ = −0.5398 × 10 ⁻¹⁵ L23 N ₂ = −0.1138 × 10 ⁻⁵ N ₄ = 0.5058 × 10 ⁻¹⁰ N ₆ = 0.5378 × 10 ⁻¹³ [Aspherical surface Data] No = 1 A = 0.134919 × 10 ^-9 B = -0.670357 × 10 ^-13 C = 0.141638 × 10 ^-16 D = -0.107368 × 10 ^-20 No = 7 A = -0.337203 × 10 ^-9 B = 0.210537 × ^{10 -12 C = -0.548794 × 10 -16} D = 0.516265 × 10 -20 No = 17 A = 0.165511 × 10 -10 B = -0.183674 × 10 -14 C = 0.108737 × 10 -18 D = -0.265080 × 10 - ²³ No = 32 A = 0.524400 × 10 ^-11 B = -0.231700 × 10 ^-15 C = 0.545900 × 10 ^-20 D = -0.529700 × 10 ^-25 [Values for conditional expressions] (1) L ₂ : nmax−nmin = _{0.002149 L 3: nmax -nmin = 0.00341} L 5: nmax -nmin = 0.001259 L 9: nmax -nmin = 0.005237 L 10: nmax -nmin = 0.003515 L 1 _{5: nmax -nmin = 0.000365 L 18} : nmax -nmin = 2.43 × 10 -5 L 19: nmax -nmin = 0.000624 L 21: nmax -nmin = 0.000469 L 23: nmax -nmin = 0.001227 (2) | f 4 / L | = 0.08 (3) f 5 /L=0.12 (4) f 6 /L=0.16 (5) D 56 /L=0.03 (6) D 6 / R 6 = 0.98 (7) | Df-Db | = 1.04 (8) | Af-Ab | = 0.21 (9) | Cf-Cb | = 0.64 (10) | Sf-Sb | = 0.19 Next, FIG. 2 shows a method of designing the projection optical system. First, the refractive index distribution of each lens constituting the projection optical system is measured, and each lens is classified into a lens having a uniform refractive index and a lens having a non-uniform refractive index. Expression (1) is used as the criterion.

Next, two types of aberrations are calculated. The first aberration is the aberration (A) when the measured refractive index is used as it is, and the second aberration is when the refractive index of a lens having a non-uniform refractive index is replaced with a uniform value. (B). As the uniform value of the refractive index to be replaced, for example, a value on the optical axis, that is, N0 is used. The aberration (B) is a target value when correcting the aberration (A) by introducing an aspheric surface. That is, in this embodiment, when the aberration (A) is corrected by introducing an aspherical surface, the aberration can be obtained if the refractive index distribution is uniform instead of introducing the aspherical surface so that the aberration becomes zero. An aspherical surface is introduced so as to obtain the aberration (B) that would have occurred.

Next, the residual aberration (A)-(B) caused by the non-uniformity of the refractive index is obtained. Next, the aberration (A ′) when the aspherical surface is introduced is determined, and the residual aberration (A ′) −
(B) is obtained, and this process is repeated until the residual aberration (A ')-(B) falls within the allowable value. Residual aberration (A ')-
When (B) falls within the allowable range, that is, when “completed”, the aspherical surface in the completed state is adopted, and an aspherical lens is manufactured according to the aspherical surface data.

FIG. 3 shows the spherical aberration, astigmatism, and distortion in the case of (A) using the data of [Refractive index non-uniformity] in Table 1 as it is, and FIG. The lateral aberration at the time of () is shown. (A) of the lateral aberration diagram shows the aberration of the light ray in the meridional image plane, and (b) shows the aberration of the light ray in the sagittal image plane. Similarly, FIGS. 5 and 6 show the refractive index N on the optical axis without using the data of [Refractive index non-uniformity] in Table 1.
Various aberrations at the time of (B), which is assumed to be uniform at 0, are shown.
FIGS. 7 and 8 show various aberrations in a completed state where the aspherical surface is introduced.

As shown in each of these figures, the aberration in the case of (A) is considerably poor and is difficult to use as a projection optical system, but the aberration in the completed state is the same as the aberration in the case of (B). It can be seen that the correction has been performed so satisfactorily. In the above embodiment, the non-uniformity of the refractive index distribution of each refractive optical member (such as a lens) constituting the projection optical system is measured, and the non-uniformity of the refractive index of each refractive optical member (such as a lens) is measured. An example has been shown in which at least one aspherical surface (correction surface) is formed in the projection optical system in order to correct the deterioration of the optical characteristics (imaging performance) of the projection optical system that occurs.

Next, referring to FIGS. 9 and 10, non-uniformity of the refractive index distribution of each refractive optical member (such as a lens) forming the projection optical system and each refractive optical member (forming the projection optical system) will be described. Examples of a method of manufacturing a projection optical system in consideration of a processing surface error of a lens or the like will be described. FIG.
7 shows a flow of a method of manufacturing a projection optical system according to a second example of the present invention. As shown in FIG. 9, in step 10, first, using an interferometer for measuring the refractive index distribution,
The distribution of the refractive index of the optical material (refractive optical member) before processing is measured. Then, information on the distribution of the refractive index of the optical material (refractive optical member) before processing measured by the interferometer for measuring the refractive index distribution is stored in the memory unit inside the computer. Here, as the optical material before processing, an optical glass plate (so-called disk member) before processing a lens having a predetermined thickness cut out from an ingot of optical glass such as a lens or the like before cutting an optical glass plate is used. The ingot itself.

When the step of measuring the refractive index distribution of the optical material (refractive optical member) before processing in step 10 is completed, the process proceeds to step 11. Step 11
Then, using a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device), a large number of optical glasses cut out from an optical glass ingot such as a lens are processed and polished, and the processing and polishing are performed. The processing and polishing steps are repeated until the polished optical component (such as a lens) has an optical design value and functions as an optical member constituting the projection optical system (until an allowable manufacturing error is reached). In addition,
In step 10 described above, when the refractive index distribution of the ingot before cutting out the optical glass plate is measured, a large number of optical glass ingots are first obtained before the processing and polishing steps in step 11 are performed. Cut out optical glass.

Next, an antireflection film is coated by a thin film forming apparatus in order from the processed and polished optical components to increase the transmittance of the optical components, and the optical components for assembling the projection optical system are manufactured. You. When the step 11 is completed, the process proceeds to the step 12. In step 12, the shape of the processing surface of each optical component is obtained by using an interferometer that measures the shape of the processing surface of the optical component in order to obtain processing error information relating to the processing surface of each optical component manufactured in step 11. Measure each. Then, information on the shape of the processed surface of each optical component measured by the interferometer that measures the processed surface shape of the optical component is stored in a memory unit inside the computer. When the measurement of the processing surface for all the optical components constituting the projection optical system is completed, the process of Step 12 is completed, and the process proceeds to Step 13.
In step 12, after the processing surface of the optical component is coated with a predetermined thin film, the shape of the processing surface of the optical component is measured. Conversely, the shape of the processing surface of the optical component is measured first. After that, the processed surface of the optical component may be coated with a predetermined thin film.

In step 13, a projection optical system is assembled using the optical components that have undergone the above steps 10 to 12, and assembly information of the projection optical system when this projection optical system is assembled (relative information of each optical component). Spacing, inclination of each optical component, eccentricity of each optical component (shift in the direction orthogonal to the optical axis), relative spacing between barrels holding each optical component, inclination of each barrel, or eccentricity of each barrel Position information (setting information) of each component including information such as (shift in the direction orthogonal to the optical axis) is stored in a memory unit inside the computer.

Next, after assembling the projection optical system, the residual aberration (remaining unnecessary optical characteristics) of the projection optical system is measured. Then, information on the measured residual aberration (remaining unnecessary optical characteristics) of the projection optical system is stored in a memory unit inside the computer. Here, the residual aberration of the projection optical system includes wavefront aberration, spherical aberration, astigmatism, field curvature,
Unnecessary optical properties that remain in the projection optical system include coma, distortion, and chromatic aberration, and include, in addition to the residual aberration, a magnification error, a telecentric error (a tilt error of the principal ray with respect to the optical axis), and the like. including.

Here, the residual aberration of the projection optical system can be obtained by measurement using test exposure for exposing a test pattern for aberration measurement to a photosensitive substrate using a test reticle, or measurement using an interferometer. it can. In the test exposure described above, the projection optical system assembled in step 13 is attached to an inspection machine for test exposure, and the test reticle installed on the object plane of the projection optical system is illuminated with light from the illumination system in the inspection machine. Then, the pattern image of the test reticle is projected and exposed on the photosensitive substrate provided on the image plane of the projection optical system. The residual aberration due to the test exposure can be obtained by developing the exposed substrate and analyzing the exposure pattern with an observation device such as an electron microscope. Step 1
When the step 3 is completed, the process proceeds to the step 14.

In step 14, each information stored in the memory section inside the computer, that is, information on the distribution of the refractive index of the optical material (refractive optical member) before processing obtained in step 10, and information obtained in step 12 Based on the information on the processed surface shape of each optical component obtained and the information on the residual aberration (remaining unnecessary optical characteristics) of the projection optical system obtained in step 13, a simulation by a computer (for example, by ray tracing or the like) Optical calculation). The residual aberration measured in step 13 by adjusting the projection optical system (adjusting the position including the tilt of the optical components and the lens barrel, the shift in the optical axis direction, or the shift in the direction orthogonal to the optical axis) based on the simulation result by the computer. It is determined whether (remaining unnecessary optical characteristics) can be corrected. In other words, in step 14, by computer simulation, for example, can the residual aberration (remaining unnecessary optical characteristics) measured in step 13 be corrected by adjusting lower-order aberrations by adjusting the projection optical system? Determine whether or not.

The simulation by the computer in step 14 is based on the information on the distribution of the refractive index of the optical material (refractive optical member) in step 10 and the information in step 12.
Not only the information on the processing surface shape of each optical component and the information on the residual aberration (remaining unnecessary optical characteristics) of the projection optical system in step 13 but also the optical design information of the projection optical system being manufactured and the information in step 13 Assembling information of the projection optical system when assembling the projection optical system (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (deviation in the direction orthogonal to the optical axis), mirror holding each optical component Position information (setting information) of each part including information such as relative spacing between the cylinders, inclination of each lens barrel, or eccentricity of each lens barrel (shift in the direction orthogonal to the optical axis).
It is preferable to carry out using.

If it is predicted that the residual aberration (remaining unnecessary optical characteristics) measured in step 14 cannot be corrected by adjusting the projection optical system, the process proceeds to step 15. In other words, when it is predicted that a high-order aberration that cannot be completely corrected by adjusting the projection optical system remains, the process proceeds to step S15. In step 15, at least one aberration component (unnecessary optical characteristic component) that cannot be corrected by the adjustment of the projection optical system can be corrected by a computer simulation (for example, optical calculation by ray tracing). The correction surface shape (spherical shape, rotationally symmetric aspherical shape, rotationally asymmetrical aspherical shape, random aspherical shape) for the processing surface (optical surface) of one optical component is calculated. The simulation by the computer in the step of calculating the correction surface shape in step 15 is performed in step 1.
0, information on the distribution of the refractive index of the optical material (refractive optical member), information on the processed surface shape of each optical component in step 12, and information on the residual aberration (remaining unnecessary optical characteristics) of the projection optical system in step 13. Not only the optical design information of the projection optical system under manufacture, but also the information of the assembly of the projection optical system when assembling the projection optical system in step 13 (relative spacing of each optical component, inclination of each optical component, each optical component Such as the eccentricity of the lens (displacement in the direction perpendicular to the optical axis), the relative distance between the barrels holding the optical components, the inclination of each barrel, or the eccentricity of each barrel (displacement in the direction perpendicular to the optical axis). This is preferably performed using the position information (setting information) of each component including the above.

Thereafter, returning to step 11, the projection optical system is once disassembled and an optical component for rework is taken out. Next, based on the information on the corrected surface shape calculated in step 15, a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device) are used to re-process an optical component for reprocessing. Processing and polishing of processing surface (optical surface),
Then, coat the reworked surface of the optical component for rework,
Steps 12, 13, and 14 are repeated.

If it is predicted that the residual aberration (remaining unnecessary optical characteristics) measured in step 14 can be corrected by adjusting the projection optical system, the process proceeds to step 16 and the projection optical system The system is adjusted. Adjustment information of the projection optical system when adjusting the projection optical system in step 16 (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (deviation in the direction orthogonal to the optical axis), each optical component The positional information (setting information) of each component including information such as the relative spacing between the barrels holding the components, the inclination of each barrel, or the eccentricity of each barrel (displacement in the direction orthogonal to the optical axis) is It is stored in a memory unit inside the computer.

Here, the adjustment of the projection optical system in step 16 includes position adjustment (adjustment including tilt, shift in the optical axis direction, and eccentricity) of a large number of optical components, and division of the projection optical system into a plurality of parts. When the lens barrel is constituted by a lens barrel, position adjustment of the split lens barrel (adjustment including tilt, shift in the optical axis direction, and eccentricity) is performed. When the step 16 is completed, the process proceeds to the step 17.

In step 17, the optical characteristics (imaging performance) of the projection optical system are measured to determine whether the residual aberration (remaining unnecessary optical characteristics) of the projection optical system is acceptable. Here, the optical characteristics (imaging performance) of the projection optical system are as follows:
As in step 13, it can be obtained by measurement using test exposure or measurement using an interferometer. If the residual aberration of the projection optical system (remaining unnecessary optical characteristics)
Is acceptable, the projection optical system is completed.

On the other hand, if the residual aberration (remaining unnecessary optical characteristics) of the projection optical system cannot be tolerated, information on the measured residual aberration (remaining unnecessary optical characteristics) of the projection optical system is stored in the computer. And the process goes to step 15 again. And step 1
In step 5, the correction surface shape (spherical surface) relating to the processing surface (optical surface) of at least one optical component at an appropriate position capable of correcting the residual aberration (remaining unnecessary optical characteristics) of the projection optical system obtained in step 17 Shape, rotationally symmetric aspherical shape, rotationally asymmetrical aspherical shape, random aspherical shape). At this time, the simulation by the computer in the step of calculating the correction surface shape in step 15 includes information on the distribution of the refractive index of the optical material (refractive optical member) in step 10 and information on the processing surface shape of each optical component in step 12. , And information on the residual aberration (remaining unnecessary optical characteristics) of the projection optical system in step 17 as well as the optical design information of the projection optical system being manufactured and the projection optical system when assembling the projection optical system in step 13 Assembly information (relative spacing of each optical component, deviation and eccentricity of each optical component in the direction perpendicular to the optical axis (deviation in the optical axis orthogonal direction),
Alternatively, the adjustment is preferably performed using information on the projection optical system at the time of adjusting the projection optical system in step 16 (information on the relative distance between the optical components, etc.).

Thereafter, the steps 11 to 17 are repeated, and the steps 11 to 17 are repeated until the residual aberration (remaining unnecessary optical characteristics) of the projection optical system can be tolerated. Thereby, a projection optical system having excellent optical performance (imaging performance) can be finally manufactured. After the step 14 or the step 17, the reworked surface calculated and machined in the step 15 and the step 11 may be all the machined surfaces of a plurality of optical components constituting the projection optical system.

Next, a method for manufacturing a projection optical system according to still another embodiment of the present invention will be described with reference to FIG. In the example shown in FIG. 9, after once assembling the projection optical system, it is determined whether or not to rework the processing surface by simulation by a computer. In the following example, before assembling the projection optical system, An example of predicting whether or not to rework a processing surface by computer simulation until the residual aberration can be corrected by adjusting the projection optical system will be described.

FIG. 10 shows a flow of a method of manufacturing a projection optical system according to the third embodiment of the present invention. FIG.
As shown at 0, in step 20, first, the distribution of the refractive index of the optical material (refractive optical member) before processing is measured using an interferometer for measuring the refractive index distribution. Then, information on the distribution of the refractive index of the optical material (refractive optical member) before processing measured by the interferometer for measuring the refractive index distribution is stored in the memory unit inside the computer. Here, as the optical material before processing, an optical glass plate (so-called disk member) before processing a lens having a predetermined thickness cut out from an ingot of optical glass such as a lens or the like before cutting an optical glass plate is used. The ingot itself.

When the step of measuring the refractive index distribution of the optical material (refractive optical member) before processing in step 20 is completed, the process proceeds to step 21. Step 21
Then, using a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device), a large number of optical glasses cut out from an optical glass ingot such as a lens are processed and polished, and the processing and polishing are performed. The processing and polishing steps are repeated until the polished optical component (such as a lens) has an optical design value and functions as an optical member constituting the projection optical system (until an allowable manufacturing error is reached). In addition,
In step 20 described above, when the refractive index distribution of the ingot before cutting out the optical glass plate is measured, a large number of optical glass ingots are first obtained before the processing and polishing steps in step 21 are executed. Cut out optical glass.

Next, an antireflection film is coated by a thin film forming apparatus in order from the processed and polished optical components to increase the transmittance of the optical components, and the optical components for assembling the projection optical system are manufactured. You. When the step 21 is completed, the process proceeds to the step 22. In step 22, the interferometer that measures the processing surface shape of the optical component is used to obtain the processing error information related to the processing surface of each optical component manufactured in step 21, and the processing surface shape of each optical component is obtained. Measure each. Then, information on the shape of the processed surface of each optical component measured by the interferometer that measures the processed surface shape of the optical component is stored in a memory unit inside the computer. When the measurement of the processing surface for all the optical components constituting the projection optical system is completed, the process of Step 22 is completed, and the process proceeds to Step 23.
In step 22, after the processing surface of the optical component is coated with a predetermined thin film, the shape of the processing surface of the optical component is measured. Conversely, the shape of the processing surface of the optical component is measured first. After that, the processed surface of the optical component may be coated with a predetermined thin film.

In step 23, each information stored in the memory section inside the computer, that is, information on the distribution of the refractive index of the optical material (refractive optical member) before processing obtained in step 20 and the information obtained in step 22. Based on the information on the processed surface shape of each optical component thus obtained, residual aberrations (remaining unnecessary optical characteristics) in the projection optical system are calculated by computer simulation (for example, optical calculation by ray tracing). Here, the residual aberration of the projection optical system includes wavefront aberration, spherical aberration, astigmatism, field curvature, coma aberration, distortion, and chromatic aberration, and unnecessary optical characteristics remaining in the projection optical system. The term includes a magnification error, a telecentric error (a tilt error of the principal ray with respect to the optical axis), and the like, in addition to the residual aberration.

Then, as a result of the prediction calculation by the computer, adjustment of the projection optical system (adjustment of the position including the inclination and shift of the optical components, the lens barrel, etc.) in step 25 described later.
It is determined whether or not the residual aberration (remaining unnecessary optical characteristics) of the projection optical system predicted by (1) can be corrected. In other words,
In step 23, it is determined by a computer simulation, for example, whether or not the residual aberration (remaining unnecessary optical characteristics) calculated in this step can be corrected by adjusting the lower-order aberration by adjusting the projection optical system. I do.
Then, information on the residual aberration (remaining unnecessary optical characteristics) of the projection optical system obtained in step 23 is stored in a memory unit inside the computer. The simulation by the computer in step 23 includes not only the information on the distribution of the refractive index of the optical material (refractive optical member) in step 20, the information on the processing surface shape of each optical component in step 22, but also the projection currently being manufactured. It is preferable to perform the process using the optical design information of the optical system.

If it is predicted that the residual aberration (remaining unnecessary optical characteristics) measured in step 23 cannot be corrected by adjusting the projection optical system, the process proceeds to step 24. In other words, when it is predicted that a higher-order aberration that cannot be completely corrected by adjusting the projection optical system remains, the process proceeds to step S24. In step 24, at least one aberration component (unnecessary optical characteristic component) which cannot be corrected by adjustment of the projection optical system can be corrected by a computer simulation (for example, optical calculation by ray tracing). The correction surface shape (spherical shape, rotationally symmetric aspherical shape, rotationally asymmetrical aspherical shape, random aspherical shape) for the processing surface (optical surface) of one optical component is calculated. The simulation by the computer in the step of calculating the correction surface shape in step 24 is performed in step 2.
This is performed using not only the information on the distribution of the refractive index of the optical material (refractive optical member) of No. 0 and the information on the processing surface shape of each optical component in step 22, but also the optical design information of the projection optical system currently being manufactured. Things are preferred.

Then, returning to step 21, based on the information on the corrected surface shape calculated in step 24, using a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device), Processing and polishing of the rework surface (optical surface) of the rework optical component, and coating of the rework surface of the rework optical component, step 2
2 and step 23 are repeated.

If it is predicted that the residual aberration (remaining unnecessary optical characteristics) measured in step 23 can be corrected by adjusting the projection optical system, the process proceeds to step 25. In step 25, the projection optical system is assembled and adjusted using each optical component that has undergone step 23, and the projection optical system is assembled. here,
As the adjustment of the projection optical system, position adjustment of many optical components (adjustment including tilt, shift in the optical axis direction, and eccentricity),
When the projection optical system is composed of a plurality of divided lens barrels, position adjustment of the divided lens barrels (adjustment including tilt, shift in the optical axis direction, and eccentricity) is performed.

Assembling information of the projection optical system when assembling the above-mentioned projection optical system (for example, positional information (setting information) of the relative distance between the optical components and the relative distance between the lens barrels holding the optical components. ) Is stored in a memory unit inside the computer, and when the process of step 25 is completed, step 2 is executed.
Move to step 6. In step 26, the optical characteristics (imaging performance) of the projection optical system are measured to determine whether the residual aberration (remaining unnecessary optical characteristics) of the projection optical system is acceptable. Here, the optical characteristics (imaging performance) of the projection optical system can be obtained by measurement using a test exposure or measurement using an interferometer, similarly to steps 13 and 17 in the example of FIG.

If the residual aberration (remaining unnecessary optical characteristics) of the projection optical system can be tolerated, the projection optical system is completed. Conversely, if the residual aberration (remaining unnecessary optical characteristics) of the projection optical system cannot be tolerated, the information on the measured residual aberration (remaining unnecessary optical characteristics) of the projection optical system is stored in a memory unit inside the computer. Remembered to
Move to step 24. Then, the correction surface shape (spherical shape, spherical surface shape, etc.) of the processing surface (optical surface) of at least one optical component at an appropriate position capable of correcting the residual aberration (remaining unnecessary optical characteristics) of the projection optical system obtained in step 26 Rotationally symmetric aspherical shape, rotationally asymmetrical aspherical shape,
(Random aspherical shape). At this time, the simulation by the computer in the step of calculating the correction surface shape in step 24 is based on the information on the distribution of the refractive index of the optical material (refractive optical member) in step 20;
In addition to the information relating to the processing surface shape of each optical component 1 and the information relating to the residual aberration (remaining unnecessary optical characteristics) of the projection optical system in step 26, the optical design information of the projection optical system being manufactured, and step 25 Information on the assembly of the projection optical system when assembling the projection optical system (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (deviation in the direction orthogonal to the optical axis), and holding of each optical component Position information (setting information) of each component including information such as the relative spacing between the barrels, the inclination of each barrel, or the eccentricity of each barrel (shift in the direction orthogonal to the optical axis).
It is preferable to carry out using.

Thereafter, the process from step 21 to step 26 is repeated, and the process from step 21 to step 26 is repeated until the residual aberration (remaining unnecessary optical characteristics) of the projection optical system can be tolerated. Thereby, a projection optical system having excellent optical performance (imaging performance) can be finally manufactured. Note that after step 23 or step 26, the reworked surface calculated and machined in step 24 and step 21 may be all the machined surfaces of a plurality of optical components constituting the projection optical system.

In the example shown in FIGS. 9 and 10,
To correct all manufacturing errors such as assembly errors and adjustment errors related to the projection optical system, processing errors related to the processing surface of the optical components constituting the projection optical system, or refractive index distribution errors of the optical components constituting the projection optical system. Alternatively, a correction member (a correction plate having no refractive power or the like) may be disposed between the object plane (reticle plane) of the projection optical system and the image plane (wafer plane, substrate plane) of the projection optical system. In this case, in order to correct the residual aberration and residual error measured in step 17 shown in FIG. 9 and step 26 shown in FIG. 10, step 15 shown in FIG.
In step 24 shown in FIG. 10, a processing shape to be processed on the surface of the correction member is calculated, and then, in step 11 shown in FIG. 9 and step 21 shown in FIG. Is preferred. Note that a method of manufacturing a projection optical system using a correction member is disclosed in
No. 03805 and JP-A-11-45842 are disclosed.

In the above, the method of manufacturing the projection optical system according to the present invention has been described with reference to FIGS. 2, 9 and 10, respectively. Next, the manufacturing method of the exposure apparatus will be described with reference to FIGS. The method will be described. FIG.
12 shows a state of a configuration of an exposure apparatus manufactured by the present invention. FIG. 12 is a flowchart of a method of manufacturing an exposure apparatus according to another embodiment of the present invention for manufacturing the exposure apparatus shown in FIG. It shows the situation.

First, as shown in FIGS. 11 and 12, first, in step 30, an illumination optical system IS for illuminating the reticle R on which a predetermined pattern is formed is manufactured and prepared so as to be incorporated in the exposure apparatus main body. . Here, step 3
The manufacturing method for the illumination optical system IS at 0 will be described later. On the other hand, as shown in FIGS.
In step 1, independently or in parallel with step 30,
The projection optical system PL is manufactured by the method shown in FIGS. 2, 9 and 10, and is prepared so as to be incorporated in the exposure apparatus main body.

Next, in step 32, the illumination optical system IS prepared in step 30 and the projection optical system PL prepared in step 31 are incorporated in the exposure apparatus main body. That is, the reticle (projection master) R is provided by the illumination optical system IS.
And illuminates the wafer (photosensitive substrate) W with a predetermined pattern image formed on the reticle R by the projection optical system PL.
The illumination optical system IS prepared in step 30 and the projection optical system P prepared in step 31 so as to project upward.
L is installed at a predetermined position. Thus, an exposure apparatus having good performance can be manufactured.

Here, in step 32, the illumination optical system IS prepared in step 30 and the projection optical system PL prepared in step 31 are mounted on a support (not shown) in FIG. Have been. A reticle stage RS for mounting a reticle R and a wafer stage (substrate stage) R for mounting a wafer (photosensitive substrate) W
S is attached to a support base (support member) not shown in FIG. Although not shown in FIG. 12, before step 32 is performed, a step of preparing each member (a step of preparing a reticle stage RS on which the reticle R is mounted; a substrate on which the photosensitive substrate W is mounted) Step of preparing stage RS; step of preparing a support (support member) that holds illumination optical system IS, projection optical system PL, reticle stage RS, and substrate stage RS at respective predetermined positions)
The respective members are prepared respectively.

Next, referring to FIG. 13, FIG.
The method of manufacturing the illumination optical system IS in Step 30 shown in FIG. 2 will be described. As shown in FIG. 13, in step 40, first, using a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device), a number of optical cut out from an ingot of optical glass such as a lens. The glass (disk member) is processed and polished, and the processed and polished optical parts (lenses, etc.) become the optical design values and function as the optical members constituting the illumination optical system IS (allowable manufacturing error and Until that time) the processing and polishing steps are repeated.

Next, an anti-reflection film is coated by a thin film forming apparatus in order from the processed and polished optical parts in order to increase the transmittance of the optical parts, and the optical parts for assembling the illumination optical system IS are manufactured. Is done. When the step 40 is completed, the process proceeds to the step 41. In step 41, the illumination optical system IS is assembled using the optical components manufactured in step 40 described above. Upon completion of the step 41, the process proceeds to a step 42.

In step 42, in order to measure the illuminance uniformity on the illuminated surface (reticle surface) of the illumination optical system IS and the telecentricity for telecentric illumination, the illuminance measuring device or the telecentric measuring device is used. It is checked whether the lighting characteristics are satisfied. If the illumination characteristics of the assembled illumination optical system IS are sufficient, the illumination optical system IS is completed. Conversely, if the illumination characteristics of the assembled illumination optical system IS are insufficient, the step is performed. Move to 43.

In step 43, the adjustment of the illumination optical system IS is performed. In this step, the adjustment of the relative distance between the optical components constituting the illumination optical system IS, the adjustment of the inclination of each optical component, and the adjustment of each optical component are performed. Adjustment of eccentricity (shift in the direction orthogonal to the optical axis), relative spacing between lens barrels holding each optical component, adjustment of tilt of the lens barrel, or adjustment of eccentricity of the lens barrel (shift in the direction orthogonal to the optical axis) And so on. And the illumination optical system IS
Until the desired lighting characteristics are obtained by adjusting
Of the illumination optical system IS and the inspection process of the illumination optical system IS in step 42 are repeated. Thereby, the illumination optical system IS having good illumination performance can be manufactured.

The above-described manufacturing method shown in FIGS. 2, 9 and 10 according to the present invention can be applied not only to the manufacturing of the projection optical system PL but also to the illumination optical system IS. Thereby, a high-performance illumination optical system IS can be realized. Therefore, an example in which the method shown in FIG. 9 is applied to a method for manufacturing the illumination optical system IS will be described with reference to FIG.

FIG. 14 is a flowchart showing another example of the method of manufacturing the illumination optical system IS according to the present invention. FIG.
In step 50, first, the distribution of the refractive index of the optical material (refractive optical member) before processing is measured using an interferometer for measuring the refractive index distribution. Then, information on the distribution of the refractive index of the optical material (refractive optical member) before processing measured by the interferometer for measuring the refractive index distribution is stored in the memory unit inside the computer. Here, as the optical material before processing, an optical glass plate (so-called disk member) before processing a lens having a predetermined thickness cut out from an ingot of optical glass such as a lens or the like before cutting an optical glass plate is used. The ingot itself.

When the step of measuring the refractive index distribution of the optical material (refractive optical member) before processing in step 50 is completed, the process proceeds to step 51. Step 51
Then, using a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device), a large number of optical glasses cut out from an optical glass ingot such as a lens are processed and polished, and the processing and polishing are performed. The processing and polishing steps are repeated until the polished optical component (such as a lens) has an optical design value and functions as an optical member constituting the projection optical system (until an allowable manufacturing error is reached). In addition,
In the above step 50, when the refractive index distribution of the ingot before cutting out the optical glass plate is measured, a large number of optical glass ingots are first obtained from the optical glass ingot before the processing and polishing steps in step 51 are executed. Cut out optical glass.

Next, an antireflection film is coated by a thin film forming apparatus in order from the processed and polished optical components in order to increase the transmittance of the optical components, and the optical components for assembling the projection optical system are manufactured. You. When the step 51 is completed, the process moves to the step 52. In step 52, the shape of the processing surface of each optical component is obtained by using an interferometer that measures the shape of the processing surface of the optical component, in order to obtain processing error information relating to the processing surface of each optical component manufactured in step 51. Measure each. Then, information on the shape of the processed surface of each optical component measured by the interferometer that measures the processed surface shape of the optical component is stored in a memory unit inside the computer. When the measurement of the processing surface for all the optical components constituting the projection optical system is completed, the process of Step 52 is completed, and the process proceeds to Step 53.
In step 52, after the processing surface of the optical component is coated with a predetermined thin film, the shape of the processing surface of the optical component is measured. Conversely, the shape of the processing surface of the optical component is measured first. After that, the processed surface of the optical component may be coated with a predetermined thin film.

In step 53, the illumination optical system I is formed by using the optical components that have passed through steps 50 to 52.
Assembling information of the illumination optical system IS when the illumination optical system IS is assembled by assembling S (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (shift in the direction orthogonal to the optical axis)) Position information (setting information) of each component including information such as relative spacing between lens barrels holding each optical component, inclination of each lens barrel, or eccentricity of each lens barrel (displacement in the direction orthogonal to the optical axis). )
Is stored in a memory unit inside the computer.

Next, after assembling the illumination optical system IS, the illumination characteristics of the illumination optical system IS, that is, the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS are measured. Then, information on the measured residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS is stored in a memory unit inside the computer. Here, the residual aberration of the illumination optical system IS includes wavefront aberration, spherical aberration, astigmatism, field curvature,
Unnecessary optical characteristics including coma, distortion, and chromatic aberration, and remaining in the illumination optical system IS include, in addition to the residual aberration, a magnification error and a telecentric error (a tilt error of the principal ray with respect to the optical axis). Illuminance non-uniformity.

Here, unnecessary optical characteristics of the illumination optical system IS can be obtained by measurement using an illuminance measuring device, a telecentric measuring device, an interferometer or the like. Step 13
When the step is completed, the process proceeds to the step.
In step 54, each information stored in the memory unit inside the computer, that is, information on the distribution of the refractive index of the optical material (refractive optical member) before processing obtained in step 50 and each information obtained in step 52 Simulation by a computer (for example, optical calculation by ray tracing, etc.) based on information on the processed surface shape of the optical component and information on the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS obtained in step 53 )I do. By the simulation result by the computer,
Remaining aberrations (remaining unnecessary optics) measured in step 53 in the adjustment of the illumination optical system IS (adjustment of the position including the tilt with respect to the optical components and the lens barrel, the shift in the optical axis direction or the shift in the optical axis orthogonal direction) (Characteristic) can be corrected. In other words, in step 54, for example, in step 5
Residual aberration measured at 3 (remaining unnecessary optical characteristics)
It is determined whether or not can be corrected by adjusting the lower-order aberration by adjusting the illumination optical system IS.

The simulation by the computer in step 54 is based on the information on the distribution of the refractive index of the optical material (refractive optical member) in step 50 and the information in step 52.
Not only the information on the processing surface shape of each optical component and the information on the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS in step 53, but also the illumination optical system I during manufacturing.
The optical design information of S and the assembling information of the illumination optical system IS when assembling the projection optical system in step 53 (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (in the direction orthogonal to the optical axis) Position information of each component including information such as relative displacement between lens barrels holding optical components, inclination of each lens barrel, or eccentricity of each lens barrel (displacement in a direction orthogonal to the optical axis). This is preferably performed using setting information)).

Here, if the residual aberration (remaining unnecessary optical characteristics) measured in step 54 is the illumination optical system I
If it is predicted that it cannot be corrected by adjusting S,
The process proceeds to step 55. In other words, when it is predicted that a higher-order aberration that cannot be completely corrected by adjusting the illumination optical system IS remains, the process proceeds to step 55. Then, in step 55, a computer simulation (for example, optical calculation by ray tracing or the like)
Accordingly, the correction surface shape (spherical shape, spherical shape, (A rotationally symmetric aspherical shape, a rotationally asymmetrical aspherical shape, a random aspherical shape). The simulation by the computer in the step of calculating the correction surface shape in step 55 includes information on the distribution of the refractive index of the optical material (refractive optical member) in step 50, information on the processing surface shape of each optical component in step 52, And the illumination optical system I in step 53
Not only information about the residual aberration of S (remaining unnecessary optical characteristics), but also optical design information of the illumination optical system IS being manufactured,
And information on assembling the illumination optical system IS when assembling the illumination optical system IS in step 53 (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (shift in the direction orthogonal to the optical axis), Position information (setting information) of each component including information such as the relative spacing between the barrels holding the optical components, the inclination of each barrel, or the eccentricity of each barrel (shift in the direction orthogonal to the optical axis).
It is preferable to carry out using.

Then, returning to step 51, at least a part of the illumination optical system IS is once disassembled and an optical component for rework is taken out. Next, based on the information on the corrected surface shape calculated in step 55, the lens processing device (optical member processing device) and the lens polishing device (optical member polishing device) are used to reprocess the optical component for reprocessing. The processing and polishing of the processing surface (optical surface) and the coating of the reprocessing surface of the optical component for reprocessing are performed, and the steps 52, 53 and 54 are repeated.

If it is predicted that the residual aberration (remaining unnecessary optical characteristics) measured in step 54 can be corrected by adjusting the illumination optical system IS, step 5
The process proceeds to step 6, where the illumination optical system IS is adjusted. Adjustment information of the illumination optical system IS when adjusting the illumination optical system IS in step 56 (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (shift in the direction orthogonal to the optical axis), Position information (setting information) of each component including information such as the relative spacing between the barrels holding each optical component, the inclination of each barrel, or the eccentricity of each barrel (shift in the direction orthogonal to the optical axis). Is stored in a memory unit inside the computer.

Here, the illumination optical system IS in step 56
The adjustment of (1) includes the position adjustment of a large number of optical components (adjustment including tilt, shift in the optical axis direction, and eccentricity), and the position of the split lens barrel when the illumination optical system IS is composed of a plurality of split lens barrels. Adjustment (adjustment including tilt, optical axis direction shift, and eccentricity)
Etc. When the above step 56 is completed, the process proceeds to step 57.

In step 57, the optical characteristics (imaging performance) of the illumination optical system IS are measured to determine whether the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS is acceptable. Here, the optical characteristics (imaging performance) of the illumination optical system IS can be obtained by measurement using the same method as in step 53. If the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS is acceptable,
The illumination optical system IS is completed.

On the other hand, if the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS cannot be tolerated, the information on the measured residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS is The data is stored in the memory unit inside the computer, and the process returns to step 55 again. Then, in step 55, the correction relating to the processing surface (optical surface) of at least one optical component at an appropriate position capable of correcting the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS obtained in step 57. The surface shape (spherical shape, rotationally symmetric aspherical shape, rotationally asymmetrical aspherical shape, random aspherical shape) is calculated. At this time, the simulation by the computer in the step of calculating the correction surface shape in step 55 includes information on the distribution of the refractive index of the optical material (refractive optical member) in step 50, and information on the processing surface shape of each optical component in step 52. And residual aberration of the illumination optical system IS in step 57 (remaining unnecessary optical characteristics)
Information on the illumination optical system IS being manufactured, as well as information on the assembly of the illumination optical system IS when assembling the illumination optical system IS in step 53 (the relative spacing of each optical component, the light of each optical component). Information on the deviation and eccentricity in the direction perpendicular to the axis (deviation in the direction perpendicular to the optical axis) or the inclination of each optical component), and the adjustment information (each optical element) of the projection optical system when adjusting the projection optical system in step 56 Information such as relative spacing of parts)
It is preferable to carry out using.

Thereafter, the process from step 51 to step 57 is repeated, and the process from step 51 to step 57 is repeated until the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS can be tolerated. Thereby, finally, the illumination optical system IS having excellent optical performance (imaging performance)
Can be manufactured. After the step 54 or the step 57, the reworked surface calculated and machined in the step 55 and the step 51 may be all the machined surfaces of a plurality of optical components constituting the illumination optical system IS.

Next, an example in which the method shown in FIG. 10 is applied to a method of manufacturing the illumination optical system IS will be described with reference to FIG. In the example shown in FIG. 14, the illumination optical system IS is once assembled, and then the computer determines whether or not to rework the processing surface by simulation. In the example shown in FIG. An example will be described in which, before assembling the IS, it is predicted whether or not to rework the processing surface by computer simulation until the residual aberration (unnecessary optical characteristics) can be corrected by adjusting the illumination optical system IS.

As shown in FIG. 15, in step 60, first, the distribution of the refractive index of the optical material (refractive optical member) before processing is measured using an interferometer for measuring the refractive index distribution. Then, information on the distribution of the refractive index of the optical material (refractive optical member) before processing measured by the interferometer for measuring the refractive index distribution is stored in the memory unit inside the computer. Here, as the optical material before processing, an optical glass plate (so-called disk member) having a predetermined thickness cut out from an optical glass ingot such as a lens before processing the lens.
Or the ingot itself before cutting out the optical glass plate.

When the step of measuring the refractive index distribution of the optical material (refractive optical member) before processing in step 60 is completed, the process proceeds to step 61. Step 61
Then, using a lens processing device (optical member processing device) and a lens polishing device (optical member polishing device), a large number of optical glasses cut out from an optical glass ingot such as a lens are processed and polished, and the processing and polishing are performed. The processing and polishing steps are repeated until the polished optical component (such as a lens) has an optical design value and functions as an optical member constituting the projection optical system (until an allowable manufacturing error is reached). In addition,
In the above step 60, when the refractive index distribution of the ingot before cutting out the optical glass plate is measured, a large number of optical glass ingots are first obtained before the processing and polishing steps in step 61 are executed. Cut out optical glass.

Next, an anti-reflection film is coated by a thin film forming apparatus in order from the processed and polished optical components in order to increase the transmittance of the optical components, and the optical components for assembling the projection optical system are manufactured. You. When the step 21 is completed, the process proceeds to the step 22. In step 62, in order to obtain processing error information on the processing surface of each optical component manufactured in step 61, the shape of the processing surface of each optical component is obtained using an interferometer that measures the processing surface shape of the optical component. Measure each. Then, information on the shape of the processed surface of each optical component measured by the interferometer that measures the processed surface shape of the optical component is stored in a memory unit inside the computer. When the measurement of the processed surface for all the optical components constituting the illumination optical system IS is completed, the process of Step 62 is completed, and the process proceeds to Step 63. In step 62, after the processing surface of the optical component is coated with a predetermined thin film, the shape of the processing surface of the optical component is measured. Conversely, the shape of the processing surface of the optical component is measured first. After that, the processed surface of the optical component may be coated with a predetermined thin film.

In step 63, each information stored in the memory section inside the computer, that is, information on the distribution of the refractive index of the optical material (refractive optical member) before processing obtained in step 60, and information obtained in step 62 Based on the obtained information on the processed surface shape of each optical component, a residual aberration (remaining unnecessary optical characteristics) in the illumination optical system IS is predicted and calculated by a computer simulation (for example, an optical calculation by ray tracing). Here, the residual aberration of the illumination optical system IS includes wavefront aberration, spherical aberration, astigmatism, curvature of field, coma, distortion, and chromatic aberration. The optical characteristics include, in addition to the residual aberration, a magnification error, a telecentric error (a tilt error of the principal ray with respect to the optical axis), an illuminance non-uniformity, and the like.

As a result of the prediction calculation by the computer, the illumination optical system IS predicted by the adjustment of the illumination optical system IS (adjustment of the position including the inclination and the shift of the optical components and the lens barrel) in step 65 described later. It is determined whether or not the residual aberration (remaining unnecessary optical characteristics) can be corrected. In other words, in step 63, for example, the residual aberration (remaining unnecessary optical characteristics) calculated in this step can be corrected by the simulation of the computer by adjusting the lower-order aberration by adjusting the illumination optical system IS. It is determined whether or not. Then, the information on the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS obtained in step 63 is stored in a memory unit inside the computer. The simulation by the computer in step 63 includes not only the information on the distribution of the refractive index of the optical material (refractive optical member) in step 60, the information on the processing surface shape of each optical component in step 62, but also the illumination currently being manufactured. It is preferable to carry out using the optical design information of the optical system IS.

Here, if the residual aberration (remaining unnecessary optical characteristics) measured in step 63 is the illumination optical system I
If it is predicted that it cannot be corrected by adjusting S,
The process proceeds to step 64. In other words, when it is predicted that a higher-order aberration that cannot be completely corrected by adjusting the illumination optical system IS remains, the process proceeds to step 64.

In step 64, an appropriate position at which an aberration component (unnecessary optical characteristic component) which cannot be completely corrected by adjusting the illumination optical system IS can be corrected by a computer simulation (for example, optical calculation by ray tracing). , A corrected surface shape (spherical shape, rotationally symmetric aspherical shape, rotationally asymmetrical aspherical shape, random aspherical shape) relating to the processing surface (optical surface) of at least one optical component in (1). The simulation by the computer in the process of calculating the correction surface shape in step 64 includes information on the distribution of the refractive index of the optical material (refractive optical member) in step 60 and information on the processing surface shape of each optical component in step 62. In addition, it is preferable that the adjustment be performed using the optical design information of the illumination optical system IS currently being manufactured.

Thereafter, returning to step 61, based on the information on the corrected surface shape calculated in step 24, the lens processing device (optical member processing device) and the lens polishing device (optical member polishing device) are used. Processing and polishing of the rework surface (optical surface) of the rework optical component, and coating of the rework surface of the rework optical component, step 6
Steps 2 and 63 are repeated.

If it is predicted that the residual aberration (remaining unnecessary optical characteristics) measured in step 63 can be corrected by adjusting the illumination optical system IS, step 6
The process proceeds to step 5. In this step 265, assembling and adjustment of the illumination optical system IS are performed using the optical components that have undergone the above step 63, and the illumination optical system IS is assembled. Here, as adjustment of the illumination optical system IS, position adjustment (adjustment including tilt, shift in the optical axis direction, and eccentricity) of a large number of optical components, and the illumination optical system IS is configured by a plurality of divided lens barrels. In such a case, there is a position adjustment (adjustment including tilt, shift in the optical axis direction, and eccentricity) of the divided lens barrel.

Information on the assembly of the illumination optical system IS when the above-described illumination optical system IS is assembled (for example, positional information (setting of relative intervals between optical components and relative intervals between lens barrels holding the optical components). Information)) is stored in the memory unit inside the computer, and when the step 65 is completed, the process proceeds to the step 66. In step 66, the optical characteristics (imaging performance) of the illumination optical system IS are measured in order to determine whether the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS is acceptable. Here, the illumination optical system I
The optical characteristics (illumination performance) of S are determined in Step 5 in the example of FIG.
3 and step 57, it can be obtained by measurement using an illuminance measurement device, a telecentric measurement device, an interferometer, or the like.

If the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS can be tolerated, the illumination optical system IS is completed. Conversely, if the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS cannot be tolerated,
Information on the measured residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS is stored in a memory unit inside the computer, and the process proceeds to step 64. And
Corrected surface shape (spherical shape, rotation) related to the processed surface (optical surface) of at least one optical component at an appropriate position where the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS obtained in step 66 can be corrected. Symmetric aspherical shape, rotationally asymmetrical aspherical shape, random aspherical shape). At this time, the simulation by the computer in the step of calculating the correction surface shape in step 64 includes information on the distribution of the refractive index of the optical material (refractive optical member) in step 60 and information on the processed surface shape of each optical component in step 61. , And not only the information on the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS in step 66, but also the optical design information of the illumination optical system IS being manufactured, and the information when the illumination optical system IS is assembled in step 65. Assembly information of the illumination optical system IS (relative spacing of each optical component, inclination of each optical component, eccentricity of each optical component (shift in the direction orthogonal to the optical axis), relative spacing between lens barrels holding each optical component It is preferable to use the position information (setting information) of each component including information such as the inclination of each lens barrel or the eccentricity of each lens barrel (shift in the direction orthogonal to the optical axis).

Thereafter, the steps 61 to 66 are repeated, and the steps 61 to 66 are repeated until the residual aberration (remaining unnecessary optical characteristics) of the illumination optical system IS can be tolerated. Thereby, finally, the illumination optical system IS having excellent optical performance (imaging performance)
Can be manufactured. Note that after step 63 or step 66, the reworked surface calculated and machined in step 64 and step 61 may be all the machined surfaces of a plurality of optical components constituting the illumination optical system IS.

In each of the examples shown in FIGS. 2 and 9 to 15, the optical systems such as the projection optical system and the illumination optical system mainly use a refractive optical member (such as a lens). As shown,
It is needless to say that the present invention can be applied to the case where each optical system has a configuration including not only a refractive optical member but also a reflective optical member (a plane mirror, a convex mirror, a concave mirror, or the like). In this case, for example, in the examples shown in FIGS. 9 to 15, in the step of measuring the shape of the processing surface, not only the processing surface of the refractive optical member but also the reflection surface (processing surface) of the reflective optical member are used. It is better to simulate after adding the shape.

Now, referring to FIGS. 1, 2 and 9 described above, FIG.
By using the exposure apparatus manufactured by the method of each example shown in FIGS. 15 to 15, a predetermined circuit pattern can be formed on a wafer or the like as a photosensitive substrate, and a semiconductor device as a micro device can be obtained. Thus, an example of a method for obtaining a semiconductor device as a micro device will be described with reference to the flowchart in FIG.

First, in step 301 of FIG. 16, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the one lot of wafers. Then, in step 303, using any one of the projection exposure apparatuses shown in FIGS. 1 and 9, the pattern image on the mask (reticle) R is transferred onto the wafer W of the lot through the projection optical system PL. Are sequentially transferred to each shot area. afterwards,
After developing the photoresist on the one lot of wafers in step 304, in step 305, etching is performed on the one lot of wafers using the resist pattern as a mask to correspond to the pattern on the mask R. Is formed in each shot region on each wafer W. Thereafter, a device such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer and the like.

According to the above-described semiconductor device manufacturing method,
A semiconductor device having an extremely fine circuit pattern can be obtained with high throughput. In addition, FIG.
Using the exposure apparatus manufactured by the method of each example shown in FIGS. 2, 9 to 15, a predetermined circuit pattern can be formed on a plate (glass substrate), and a liquid crystal display element as a micro device You can also get. Therefore, an example of a method for obtaining a liquid crystal display element as a micro device will be described with reference to the flowchart in FIG.

In FIG. 17, a pattern forming step 40 is performed.
In 1, a so-called photolithography process of transferring and exposing a pattern of a reticle to a photosensitive substrate (a glass substrate coated with a resist) using the exposure apparatus of the present embodiment is performed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate is subjected to various processes such as a developing process, an etching process, and a reticle peeling process, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming process 402.

Next, in a color filter forming step 402, a color filter in which a large number of sets of three dots corresponding to R (Red), G (Green) and B (Blue) are arranged in a matrix is formed. Then, after the color filter forming step 402, a cell assembling step 403 is performed. In the cell assembling step 403, a pattern forming step 4
A liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in step 01, the color filter obtained in the color filter forming 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 with high throughput.

[0124]

As described above, according to the present invention, a projection optical system which can use one or a plurality of optical components such as a lens having a non-uniform refractive index and can secure necessary optical performance. And an illumination optical system, and further, an exposure apparatus. Therefore, the manufacturing costs of the projection optical system, the illumination optical system, and the exposure apparatus can be significantly reduced. In addition, if an exposure method and a method for manufacturing a micro device using these apparatuses are performed, a very good micro device with low yield can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a projection optical system according to the present invention.

FIG. 2 is a process chart showing a method for designing (or manufacturing) a projection optical system according to the present invention.

FIG. 3 is a diagram showing spherical aberration, astigmatism, and distortion when a lens having a non-uniform refractive index is used and an aspheric surface is not introduced.

FIG. 4 is a diagram showing lateral aberration when a lens having a non-uniform refractive index is used and no aspherical surface is introduced.

FIG. 5 is a diagram showing spherical aberration, astigmatism, and distortion when a lens having a non-uniform refractive index is replaced with a lens having a uniform refractive index.

FIG. 6 is a diagram showing lateral aberration when a lens having a non-uniform refractive index is replaced with a lens having a uniform refractive index.

FIG. 7 is a diagram showing spherical aberration, astigmatism, and distortion when an aspheric surface is introduced using a lens having a non-uniform refractive index.

FIG. 8 is a diagram illustrating lateral aberration when an aspheric surface is introduced using a lens having a non-uniform refractive index.

FIG. 9 is a process chart showing another method for manufacturing a projection optical system according to the present invention.

FIG. 10 is a process chart showing still another method of manufacturing a projection optical system according to the present invention.

FIG. 11 is a view showing a configuration of an exposure apparatus manufactured by the present invention.

FIG. 12 is a process chart showing a method of manufacturing an exposure apparatus according to the present invention.

FIG. 13 is a process chart showing one method of manufacturing an illumination optical system.

FIG. 14 is a process chart showing another method of manufacturing the illumination optical system.

FIG. 15 is a process chart showing still another method of manufacturing the illumination optical system.

FIG. 16 is a flowchart showing a method for manufacturing a semiconductor device as a micro device.

FIG. 17 is a flowchart showing a method for manufacturing a liquid crystal display element as a micro device.

[Explanation of symbols]

L1 to L24: Lenses G1 to G6: Lens group R: Reticle W: Wafer AS: Aperture stop

Claims (23)

[Claims] 1. A projection optical system for projecting and transferring a pattern on a projection original onto a photosensitive substrate, wherein one or more lenses having a non-uniform refractive index in a radial direction about the optical axis are used. A projection optical system having one or more aspherical surfaces for correcting aberrations caused by the non-uniformity of the refractive index of the lens. 2. For each lens having a non-uniform refractive index, the maximum value of the refractive index is nmax and the minimum value is nmin.
2. The projection optical system according to claim 1, wherein: nmax-nmin> 1.times.10.sup.- ⁷ . 3. A first lens group having a positive refractive power, a second lens group having a negative refractive power, and
A third lens group having a positive refractive power, a fourth lens group having a negative refractive power, a fifth lens group having a positive refractive power, and a sixth lens group having a positive refractive power. The projection optical system according to claim 1, wherein: 4. The aspherical surface of at least one of a lens surface of a lens belonging to the first lens group and a lens surface of a lens disposed closest to the first lens group in the second lens group. 4. The projection optical system according to claim 3, wherein the projection optical system is formed and satisfies the following condition: | Df-Db |> 0.1. Here, Df = Rf · sinwf · λ / (NA · Ymax) Db = Rb · sinwb · λ / (NA · Ymax) Rf: radius of the wavefront shape with respect to the maximum image height in a system in which the aspheric surface is replaced with a spherical surface. (Absolute amount of image plane incident angle) wf: incident azimuth angle of wavefront shape with respect to maximum image height in a system in which the aspheric surface is replaced with a spherical surface Rb: wavefront with respect to maximum image height in a system employing the aspheric surface Radius of shape (absolute amount of image plane incident angle) wb: incident azimuth angle of wavefront shape with respect to maximum image height in a system employing the aspheric surface λ: wavelength used NA: maximum image side numerical aperture Ymax: maximum image height It is. 5. The aspheric surface of at least one of a lens surface of a lens belonging to the second lens group and a lens surface of a lens disposed closest to the second lens group in the third lens group. 5. The projection optical system according to claim 3, wherein the projection optical system is formed and satisfies a condition of | Af-Ab |> 0.02. Where Af = (4Rf ⁴ -3Rf ² ) cos2wf · λ
/ (NA · Ymax) Ab = (4Rb ⁴ -3Rb ² ) cos2wb · λ / (N
A · Ymax) Rf: radius of the wavefront shape with respect to the maximum image height (absolute amount of image plane incident angle) wf: the maximum of the system in which the aspheric surface is replaced by a spherical surface in a system in which the aspheric surface is replaced by a spherical surface The incident azimuth angle of the wavefront shape with respect to the image height Rb: the radius of the wavefront shape with respect to the maximum image height (absolute amount of the image plane incident angle) wb: for the system employing the aspherical surface, wb: the system employing the aspherical surface The incident azimuth angle of the wavefront shape with respect to the maximum image height λ: wavelength used NA: maximum image side numerical aperture Ymax: maximum image height 6. A lens belonging to the third lens group and the fourth lens group, at least one of the lens surfaces is formed by the aspherical surface, and satisfies the condition: | Cf−Cb |> 0.06. The projection optical system according to claim 3, wherein ^{However, Cf = (10Rf 5 -12Rf 3} + 3Rf) si
nwf × λ / (NA · Ymax) Cb = (10Rb ⁵ −12Rb ³ + 3Rb) sinwb
× λ / (NA · Ymax) Rf: radius of wavefront shape with respect to the maximum image height (absolute amount of image plane incident angle) wf: system in which the aspheric surface is replaced by a spherical surface in a system in which the aspheric surface is replaced by a spherical surface , The incident azimuth angle of the wavefront shape with respect to the maximum image height Rb: the radius of the wavefront shape with respect to the maximum image height (absolute amount of the image plane incident angle) wb: the system employing the aspheric surface In the system, the incident azimuth angle of the wavefront shape with respect to the maximum image height λ: used wavelength NA: maximum image side numerical aperture Ymax: maximum image height 7. At least one of the lens surfaces of the lenses belonging to the fifth lens group and the sixth lens group is formed by the aspheric surface, and satisfies the condition: | Sf−Sb |> 0.02. 3. The method according to claim 1, wherein
Or the projection optical system according to 6. However, Sf = (20Rf ⁶ -30Rf ⁴ + 12Rf ² −
1) · λ / (NA · Ymax) Sb = (20Rb ⁶ −30Rb ⁴ + 12Rb ² −1) ·
λ / (NA · Ymax) Rf: radius of the wavefront shape with respect to the maximum image height (absolute amount of image plane incident angle) wf: for a system in which the aspheric surface is replaced by a spherical surface wf: in a system in which the aspheric surface is replaced by a spherical surface The incident azimuth angle of the wavefront shape with respect to the maximum image height Rb: the radius of the wavefront shape with respect to the maximum image height (absolute amount of the image plane incident angle) wb: the system using the aspheric surface , The incident azimuth of the wavefront shape with respect to the maximum image height λ: wavelength used NA: maximum image side numerical aperture Ymax: maximum image height 8. A method of manufacturing a projection optical system for projecting an image of a predetermined pattern formed on a projection original onto a photosensitive substrate, wherein a first step of measuring non-uniformity of refractive indices of a plurality of refractive optical members is performed.
A second step of calculating an aberration generated by the refractive optical member having a non-uniform refractive index; a third step of calculating an aspherical shape capable of correcting the aberration calculated in the second step; A method of manufacturing a projection optical system, comprising: a fourth step of applying the aspherical shape calculated in the third step to a refractive optical member; and a fifth step of assembling the refractive optical member. 9. The non-uniformity of the refractive index is a refractive index distribution in a radial direction about the optical axis, and the aspherical shape is a rotationally symmetric shape about the optical axis. The manufacturing method according to claim 8, wherein 10. A method of manufacturing a projection optical system for projecting an image of a predetermined pattern formed on a projection master onto a photosensitive substrate, wherein a first method for measuring non-uniformity of refractive indices of a plurality of refractive optical members.
A measuring step; a processing step of processing the plurality of refractive optical members after the first measuring step; a second measuring step of measuring a shape of a processed surface of the plurality of refractive optical members after the processing step; An assembling step of assembling the projection optical system using the plurality of refractive optical members having undergone the second measuring step; and a third measuring step of measuring remaining unnecessary optical characteristics of the projection optical system having undergone the assembling step; In order to correct the remaining unnecessary optical characteristics of the projection optical system, at least one of the plurality of refractive optical members based on the measurement information obtained in the first, second, and third measurement steps. A calculating step of calculating a corrected surface shape related to a processing surface; By using a refractive optical member reworked in the reworking step and a refractive optical member worked in the processing step, or by using a refractive optical member reworked in the reworking step; A finishing step of completing the projection optical system. 11. The method according to claim 10, wherein the calculating step further calculates a correction surface shape using optical design information of the projection optical system. 12. The method of manufacturing a projection optical system according to claim 10, wherein said calculating step further calculates a correction surface shape using assembly information in said assembling step. . 13. The projection optical system according to claim 10, wherein said finishing step includes an adjusting step of adjusting at least one position of said plurality of refractive optical members. Method of manufacturing the system. 14. A step of preparing a projection optical system manufactured by the method of manufacturing a projection optical system according to claim 10; and preparing an illumination optical system for illuminating the projection original. Illuminating a projection original with the illumination optical system, and projecting an image of a predetermined pattern formed on the projection original by the projection optical system onto a photosensitive substrate. Installing the projection optical system at a predetermined position. 15. A method of manufacturing a projection optical system for projecting an image of a predetermined pattern formed on a projection original onto a photosensitive substrate, wherein a first step of measuring non-uniformity of refractive indices of a plurality of refractive optical members is performed.
A measuring step; a processing step of processing the plurality of refractive optical members after the first measuring step; a second measuring step of measuring a shape of a processed surface of the plurality of refractive optical members after the processing step; In order to correct the remaining unnecessary optical characteristics of the projection optical system caused by the non-uniformity of the refractive index of the plurality of refractive optical members and the processing error of the processing surface of the plurality of refractive optical members, A calculating step of calculating a correction surface shape for at least one processed surface of the plurality of refractive optical members based on each measurement information obtained in the first and second measuring steps; A reworking step of reworking at least one working surface of the plurality of refraction optical members based on the information on the correction surface shape; Method of manufacturing a projection optical system which comprises a; finishing step to complete the projection optical system by using the refractive optical member was reworked or by the reprocessing steps using a folding optical element. 16. The method according to claim 15, wherein said calculating step further calculates a correction surface shape using optical design information of said projection optical system. 17. The method of manufacturing a projection optical system according to claim 15, wherein said calculating step further calculates a correction surface shape using the assembly information in said assembling step. . 18. The projection optical system according to claim 15, wherein said finishing step includes an adjusting step of adjusting at least one position of said plurality of refractive optical members. Method of manufacturing the system. 19. A step of preparing a projection optical system manufactured by the method for manufacturing a projection optical system according to claim 15, and preparing an illumination optical system for illuminating the projection original. Illuminating a projection original with the illumination optical system, and projecting an image of a predetermined pattern formed on the projection original by the projection optical system onto a photosensitive substrate. Installing the projection optical system at a predetermined position. 20. A method of manufacturing an illumination optical system for illuminating an original to expose an image of a predetermined pattern formed on the original onto a photosensitive substrate, wherein the refractive indexes of a plurality of refractive optical members are nonuniform. The first to measure sex
A measuring step; a processing step of processing the plurality of refractive optical members after the first measuring step; a second measuring step of measuring a shape of a processed surface of the plurality of refractive optical members after the processing step; An assembling step of assembling the illumination optical system using the plurality of refractive optical members having undergone the second measuring step; and a third measuring step of measuring remaining unnecessary optical characteristics of the illumination optical system having undergone the assembling step; In order to correct the remaining unnecessary optical characteristics of the illumination optical system, at least one of the plurality of refractive optical members based on the measurement information obtained in the first, second, and third measurement steps. A calculating step of calculating a corrected surface shape related to a processing surface; By using a refractive optical member reworked in the reworking step and a refractive optical member worked in the processing step, or by using a refractive optical member reworked in the reworking step; A finishing step of completing the illumination optical system; and a method of manufacturing the illumination optical system. 21. A method of manufacturing an illumination optical system for illuminating an original in order to expose an image of a predetermined pattern formed on the original onto a photosensitive substrate, wherein a plurality of refractive optical members have non-uniform refractive indices. The first to measure sex
A measuring step; a processing step of processing the plurality of refractive optical members after the first measuring step; a second measuring step of measuring a shape of a processed surface of the plurality of refractive optical members after the processing step; In order to correct the remaining unnecessary optical characteristics of the illumination optical system caused by the non-uniformity of the refractive index of the plurality of refractive optical members and the processing error of the processing surface of the plurality of refractive optical members, A calculating step of calculating a correction surface shape for at least one processed surface of the plurality of refractive optical members based on each measurement information obtained in the first and second measuring steps; A reworking step of reworking at least one working surface of the plurality of refraction optical members based on the information on the correction surface shape; Production method of the illumination optical system which comprises a; finishing step to complete the illumination optical system by using the refractive optical member was reworked or by the reprocessing steps using a folding optical element. 22. A step of preparing an illumination optical system manufactured by the method of manufacturing an illumination optical system according to claim 20; and projection for projecting an image of the pattern of the original onto a photosensitive substrate. Preparing an optical system; illuminating the original with the illumination optical system, and projecting the image of a predetermined pattern formed on the original by the projection optical system onto a photosensitive substrate. Installing an optical system and the projection optical system at predetermined positions. (23) The method according to the above (14), (19) or (22).
A preparation step of preparing an exposure apparatus manufactured by the method of manufacturing an exposure apparatus according to any one of claims 1 to 3, an illumination step of illuminating the original using the illumination optical system, and an illumination step of using the projection optical system. A method for manufacturing a micro device, comprising: an exposure step of exposing an image of a pattern of an original onto the photosensitive substrate; and a development step of developing the photosensitive substrate exposed in the exposure step.