JP2004335746A - Projection optical system, aligner, and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection optical system which has little aberration and has no degradation in imaging performance when it is used in a liquid-immersed state, and also to provide an exposure apparatus and an exposure method. <P>SOLUTION: The projection aligner which can be used in a liquid-immersed state is so structured as to satisfy a formula 1<R/Y<7, where R is the curvature radius of a lens surface closest to a substrate of the projection aligner and Y is the maximum height of an image projected on a photosensitive surface. In the case that a liquid for liquid immersion absorbs light, part of a glass material used in the projection aligner is formed of one having a low transmissivity, and a distance that a light beam having a long optical path in the liquid travels in the glass material having a low transmissivity is made short while a distance that a light beam having a short optical path in the liquid travels in the glass material having a low transmissivity is made long. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

この投影露光装置による最大像高Ｙは、当該投影露光装置固有の値であり、１３．７３ｍｍである。又、最も基板側のレンズ面の曲率半径（Ｇ２３−Ｒ２）は、５２．０５７ｍｍである。よって、Ｒ／Ｙの値は、３．７９１となる。
また、この投影露光装置において用いられる液浸用液体１ｃｍあたりの光の透過率Ｔ１は、０．９０であり、液体中の光路のうち短いものの距離Ｕ１は、０．３５６ｃｍであり、長いものの距離Ｌ１は、０．５９８ｃｍである。又、投影光学系内の吸収率の高いレンズ硝材１ｃｍあたりの光の透過率Ｔ２は、０．９８であり、Ｕ１の光路を投影光学系内でたどる光線の当該レンズ内を透過する光路の距離Ｕ２は、５．０４９ｃｍ、Ｌ１の光路を投影光学系内でたどる光線の当該レンズ内を透過する光路の距離Ｌ２は、２．５０５ｃｍである。このＵ２、Ｕ２の値はＬ１、Ｌ１の投影光学系内の光路を計算することにより求めることができる。よって、｛１−（Ｔ１＾Ｕ１）＊（Ｔ２＾Ｕ２）｝／｛１−（Ｔ１＾Ｌ１）＊（Ｔ２＾Ｌ２）｝の値は、１．２１２となり、結像性能に悪影響を与えることはない。
ここで、比較として、このような吸収率の高いレンズを入れない場合、即ち、前記において吸収率の高いとされたレンズが他のレンズと同様に光をほとんど吸収せず透過する場合、近似的にＴ２を１と考えることができるため、｛１−（Ｔ１＾Ｕ１）＊（Ｔ２＾Ｕ２）｝／｛１−（Ｔ１＾Ｌ１）＊（Ｔ２＾Ｌ２）｝の値は、０．６０３となり、光の強度差が大きく、結像性能に悪影響を与える。
【００１９】
本発明に基づく具体的な第２実施例を説明する。
第２実施例は図４の構成に基づくもので、表２のレンズデータを有した投影光学系である。
【００２０】
【表２】

この投影露光装置による最大像高Ｙは、当該投影露光装置固有の値であり、１３．７３ｍｍである。又、最も基板側のレンズ面の曲率半径（Ｇ２７−Ｒ２）は、４２．１８６ｍｍである。よって、Ｒ／Ｙの値は、３．０７３となる。
また、この投影露光装置において用いられる液浸用液体１ｃｍあたりの光の透過率Ｔ１は、０．９０であり、液体中の光路のうち短いものの距離Ｕ１は、０．７６４ｃｍであり、長いものの距離Ｌ１は、１．３７７ｃｍである。又、投影光学系内の吸収率の高いレンズ硝材１ｃｍあたりの光の透過率Ｔ２は、０．９８であり、計算によりＵ１の光路を投影光学系内でたどる光線の当該レンズ内を透過する光路の距離Ｕ２は、４．３１５ｃｍ、Ｌ１の光路を投影光学系内でたどる光線の当該レンズ内を透過する光路の距離Ｌ２は、１．１４６ｃｍである。
よって、｛１−（Ｔ１＾Ｕ１）＊（Ｔ２＾Ｕ２）｝／｛１−（Ｔ１＾Ｌ１）＊（Ｔ２＾Ｌ２）｝の値は、０．９９７となり、結像性能に悪影響を与えることはない。
【００２１】
ここで、比較として、このような吸収率の高いレンズを入れない場合、即ち、前記において吸収率の高いとされたレンズが他のレンズと同様に光をほとんど吸収せず透過する場合、近似的にＴ２を１と考えることができるため、｛１−（Ｔ１＾Ｕ１）＊（Ｔ２＾Ｕ２）｝／｛１−（Ｔ１＾Ｌ１）＊（Ｔ２＾Ｌ２）｝の値は、０．５７３となり、光の強度差が大きく結像性能に悪影響を与える。
【００２２】
【発明の効果】本発明では、液浸の露光装置であっても収差や結像性能を劣化させることなく結像可能な投影露光装置を提供することができる。
特に、液浸に用いる液体が光を吸収する場合には、結像性能の劣化を回避することができ、所望の微細パターンを正確に焼き付けることができる。
【図面の簡単な説明】
【図１】は、液浸投影露光装置の概要図である。
【図２】は、液浸投影露光装置のうち、液浸となる部分の構成図である。
【図３】は、本発明の第１実施例による投影露光装置の光学系の構成図である。
【図４】は、本発明の第２実施例による投影露光装置の光学系の構成図である。
【符号の説明】
１・・・光源
２・・・照明光学系
３・・・レチクル
４・・・レチクルステージ
５・・・投影光学系
６・・・液体遮断板
７・・・ウエハステージ
８・・・ウエハ
８ａ・・・像面
９・・・投影光学系の最もウエハ側のレンズ
Ａ・・・光線
Ｂ・・・液体[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus having a projection optical system for printing and transferring a pattern drawn on an original onto a substrate, and an exposure method.
[0002]
2. Description of the Related Art In recent years, miniaturization of a pattern transferred to a wafer as a photosensitive substrate has been desired. In order to achieve this, there are two methods of reducing the exposure wavelength and increasing the numerical aperture of the projection optical system. Conventionally, among these methods, an immersion type projection exposure apparatus has been proposed as one of methods for increasing the numerical aperture of a projection optical system. The liquid immersion type projection exposure apparatus has a space between the wafer surface and the lens surface of the projection optical system closest to the wafer, that is, the entire working distance (working distance) (hereinafter referred to as the working space) or the wafer side. This is a device that fills a space with a liquid such as water or oil. For example, the refractive index of air occupying the operating space in normal use is 1.0, while the refractive index of oil is, for example, about 1.6. Therefore, if the entire working space or the space on the wafer side is replaced with such a liquid having a high refractive index, the numerical aperture on the wafer side of the projection optical system can be increased, and the exposure pattern can be miniaturized. .
[0003]
[Patent Document 1] JP-A-2000-58436
[0004]
In the above-mentioned conventional liquid immersion type projection exposure apparatus, when the entire working space is replaced with a liquid having a high refractive index, the refractive index of the lens closest to the wafer in the projection optical system is changed. There is no problem if the value of the refractive index is the same as the value of the refractive index of the liquid, but in general, the value of the refractive index of the lens glass material is different from the value of the refractive index of the liquid used for immersion. Light is refracted by the difference in the rates, causing aberration.
Incidentally, a liquid immersion type optical system generally does not assume that light emitted from a lens forms an image in air, but aims to form an image in a liquid. Therefore, the generated aberration is different from the case where it is used in normal air.
[0005]
When aberration occurs in such an immersion type optical system, it is possible to correct it.However, depending on the shape of the lens, it may not be possible to correct it by correction. There is a problem that it is necessary to solve this problem.
In general, in a liquid immersion type projection optical system, the light transmittance of a lens used for the lens and the light transmittance of a liquid used for the liquid immersion often differ. This tendency is particularly remarkable in the short wavelength region. In vacuum ultraviolet light such as excimer light represented by ArF, the transmittance of the lens material is high, but the liquid used for immersion absorbs light. Therefore, the transmittance is lower than that of the glass material.
[0006]
For this reason, if the optical path of the light beam imaged on the wafer is different, the amount of light absorbed in the liquid is different, which has a problem of adversely affecting the imaging performance. That is, the light beam imaged on the wafer is such that a light beam originating from one point on the reticle passes through the projection optical system and is focused on one point on the wafer. Instead of following the same optical path in the optical system, light rays that follow various optical paths are condensed and imaged on the wafer. For this reason, when the immersion liquid absorbs light, the distance through which the light passes varies depending on the optical path followed by the light rays, and the transmission amount of each light ray also differs. As a result, the intensity of light is generated due to the difference in the optical path followed by the light rays, and this adversely affects the imaging performance.
To be more specific, referring to FIG. 3, among the light rays imaged at the position of the maximum image height, the optical path length passing through the liquid for liquid immersion has the shortest distance U1 and the longest distance L1. The distance that passes through the inside is greatly different. When this liquid absorbs light, the intensity of each light beam varies, deteriorating the imaging performance. Therefore, it is an issue to prevent the deterioration of the imaging performance.
[0007]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems.
That is, the invention according to claim 1 has a projection optical system that transfers a pattern drawn on an original to a photosensitive surface of a substrate, and a lens surface closest to the substrate of the projection optical system and a photosensitive surface of the substrate. In a projection exposure apparatus formed so as to be able to immerse a predetermined liquid in a space between the projection optical system, the radius of curvature of the lens surface of the projection optical system closest to the substrate is R, and the projection optical system is projected on the photosensitive surface of the substrate. When the maximum image height is Y, 1 <R / Y <7
Is a projection exposure apparatus characterized by being formed so as to satisfy the following.
Here, the liquid immersion means that a space between the lens surface closest to the substrate side of the projection optical system and the photosensitive surface is filled with liquid.
The maximum image height Y indicates a distance from the image forming center to the image forming position farthest from the image forming center on the photosensitive surface. The maximum image height is a value unique to the projection exposure apparatus, and means the maximum distance from the image forming center where an image can be formed without being affected by aberration or the like. For this reason, if this value is too small, the exposure area per exposure becomes narrow, the production efficiency is remarkably reduced, and the significance as a production device is lost.
[0008]
The invention according to claim 2 has a projection optical system for transferring a pattern drawn on an original to a photosensitive surface of a substrate, and a projection optical system between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate. In a projection exposure apparatus formed so as to be able to immerse a predetermined liquid into a space, all or a part of a glass material used for the projection optical system is formed of a light-absorbing glass material and transmitted through the liquid. The distance over which one of the light beams passes through the glass material having the light absorption is longer than the distance at which another light beam having a longer distance transmitting through the liquid than the one light beam passes through the glass material having the light absorption. A projection exposure apparatus characterized in that it is shortened.
This allows the amount of light absorbed by each light beam to be close even if the liquid for immersion absorbs light or the optical path is different, and forms an image on the photosensitive surface of the substrate. Performance degradation can be avoided.
[0009]
The invention according to claim 3 has a projection optical system for transferring a pattern drawn on an original to a photosensitive surface of a substrate, and a projection optical system between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate. In a projection exposure apparatus formed so as to be capable of immersion by inserting a predetermined liquid into the space, the optical path for forming an image at a position where the maximum image height is projected on the photosensitive surface of the substrate, The optical path having the shortest optical path length between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate has an absorptance of light in an optical path in the projection optical system that travels from the original to the substrate. KU, the longest optical path between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate is the absorption in the optical path in the projection optical system that travels from the master to the substrate. When the ratio is KL, the projection optics All or a part of the glass material used for is formed of a glass material having light absorption, the light ray that follows the short optical path of the light transmitted through the liquid, the light transmitted through the glass material having the light absorption is lengthened, Light rays that follow an optical path having a long distance to pass through the liquid, by shortening the distance that passes through the light-absorbing glass material,
0.8 <KU / KL <1.25
Is a projection exposure apparatus characterized by being formed so as to satisfy the following.
[0010]
According to a fourth aspect of the present invention, in the projection exposure apparatus according to the third aspect, the transmittance per unit of the liquid medium immersed in the space is T1, and the maximum image height projected on the photosensitive surface is T1. Of the optical paths for forming an image at a certain position, the optical path length between the lens surface of the projection optical system closest to the substrate and the photosensitive surface is the shortest optical path distance U1, and the longest optical path is The distance is defined as L1, the transmittance per unit of the glass material having light absorption in the projection optical system is defined as T2, and the length of the shortest light path passing through the glass material at the distance U1 is defined as U2. Assuming that the length of a light ray traveling along the long optical path distance L1 and passing through the glass material is L2,
0.8 <{1- (T1 @ U1) * (T2 @ U2)} / {1- (T1 @ L1) * (T2 @ L2)} <1.25
Is a projection exposure apparatus characterized by being formed so as to satisfy the following.
Here, * means a product, ＾ means a power, and (T1 ＾ U1) means T1 raised to the power of U1.
[0011]
Further, according to a fifth aspect of the present invention, in the method of exposing using the projection exposure apparatus according to any one of the first to fourth aspects, an illumination step of illuminating the original with predetermined exposure light; An exposure step of exposing a pattern image of an original onto a photosensitive surface of a substrate via a projection optical system 5.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a projection exposure apparatus according to the present invention will be described with reference to FIGS. FIG. 1 is a view showing a projection exposure apparatus according to the present invention.
In the present embodiment, in an exposure method including an illumination step and an exposure step, a pattern image of reticle 3 as an original is formed on photosensitive surface 8a of wafer 8 as a substrate. That is, a light beam emitted from a light source 1 such as an ArF excimer laser light source passes through an illumination optical system 2 and uniformly irradiates a pattern surface of a reticle 3 as an original placed on a reticle stage 4. The exposure light emitted from the pattern surface of the reticle 3 forms an image of the pattern surface of the reticle 3 on the photosensitive surface 8a of the wafer 8 placed on the XY stage 7 via the projection optical system 5.
On the XY stage 7, a box-shaped liquid blocking plate 6 is provided. FIG. 1 shows only a cross section of the liquid blocking plate 6 for simplicity. Then, a liquid such as water, oil, or the like is put into a space surrounded by the liquid blocking plate 6, and the working space can be made liquid. When the projection exposure apparatus of the present invention is used in a liquid immersion state, the space between the wafer 8 and the surface of the projection optical system 5 on the wafer 8 side is completely immersed in the liquid by introducing the liquid B up to the broken line portion in FIG. The Rukoto.
[0013]
Here, the maximum image height formed on the exposure surface in FIG. 3 is Y (Y indicates the distance from the image formation center to the image formation position farthest on the photosensitive surface), and the projection optical system is closest to the substrate. Where R is the radius of curvature of the lens surface,
1 <R / Y <7
By satisfying the above condition, aberration can be easily corrected without increasing the size of the lens.
[0014]
When R / Y is 1 or less, the maximum image height formed on the exposure surface is larger than the radius of curvature, and it is difficult to eliminate aberration by correction or the like. In particular, in the case of a concave lens having a large aperture and a radius close to the radius of curvature, a part of the light beam emitted from the lens may enter the lens again, and in this case, the imaging performance is extremely deteriorated. Further, with a lens having a small radius of curvature, it is difficult to supply and discharge the liquid into the space between the lens and the substrate in a short period of time, which lowers the throughput and impairs the function as a production device. Further, when R / Y is 7 or more, it becomes difficult to correct the image surface aberration, and it is necessary to increase the outer diameter of the lens. Therefore, in order to ensure the function as a production device without increasing the size of the lens, R / Y needs to be within the above range.
In particular, if attention is paid to improving the throughput of the production apparatus, it is more preferable that the range of 2 <R / Y <7 is satisfied.
Further, in the projection optical system, the amount of light absorbed between the reticle 3 as the original plate and the wafer 8 as the substrate is made substantially the same, regardless of the optical path of the light, so that the light of the liquid used for immersion can be obtained. This is to eliminate the deterioration of the imaging performance caused by the absorption of light. Specifically, a part of the glass material used in the projection optical system is formed of a glass material having a low transmittance, and a light ray in an optical path having a long transmission distance in a liquid has a short transmission distance in a glass material having a low transmittance. Light rays in an optical path having a short distance transmitted through a liquid have a longer distance transmitted through a glass material having a low transmittance.
[0015]
In the projection optical system having such a configuration, even if the light rays emitted from the same starting point follow different optical paths, the light absorption amounts are almost the same, and the light of the same intensity reaches the wafer 8, so that the image forming performance is improved. Does not adversely affect
Although the amount of light absorption is adjusted by using a glass material having a low light transmittance, a gas that absorbs light, for example, a part of the atmosphere is introduced into the space between the lens and the lens in the projection optical system. Thus, the same effect can be desired. However, since such a gas causes clouding of the lens surface, and the fluctuation of the gas deteriorates the imaging performance, a method of adjusting the transmittance by the gas is appropriate because no solution is found. Not a solution.
[0016]
What can be used as a lens that absorbs light as described above is also limited in the projection optical system, and it is difficult to make the amount of absorption completely the same regardless of the optical path. .25 has almost no effect on the imaging performance. In other words, if it is out of this range, the amount of light absorption differs depending on the optical path, and the imaging performance is remarkably deteriorated. Does not deteriorate.
[0017]
A first specific example according to the present invention will be described.
The first embodiment is based on the configuration shown in FIG. 3 and is a projection optical system having the lens data shown in Table 1. Here, r is the radius of curvature, d is the center thickness / surface interval, and n is the refractive index.
[0018]
[Table 1]

The maximum image height Y of the projection exposure apparatus is a value unique to the projection exposure apparatus, and is 13.73 mm. The radius of curvature (G23-R2) of the lens surface closest to the substrate is 52.57 mm. Therefore, the value of R / Y is 3.791.
Further, the transmittance T1 of light per 1 cm of the immersion liquid used in the projection exposure apparatus is 0.90, the short distance U1 of the optical paths in the liquid is 0.356 cm, and the long distance L1 is 0.598 cm. The transmittance T2 of light per cm of the lens glass material having a high absorptance in the projection optical system is 0.98, and the distance of the optical path of the light ray that follows the optical path of U1 in the projection optical system and passes through the lens is 0.98. U2 is 5.049 cm, and the distance L2 of an optical path of a light ray that follows the optical path of L1 in the projection optical system and passes through the lens is 2.505 cm. The values of U2 and U2 can be obtained by calculating the optical paths in the projection optical system of L1 and L1. Therefore, the value of {1- (T1 @ U1) * (T2 @ U2)} / {1- (T1 @ L1) * (T2 @ L2)} is 1.212, which adversely affects the imaging performance. There is no.
Here, as a comparison, when a lens having such a high absorptance is not inserted, that is, when a lens determined to have a high absorptance transmits light almost without absorbing light like other lenses, approximately Since T2 can be considered to be 1, the value of {1- (T1 ＾ U1) * (T2 ＾ U2)} / {1- (T1 ＾ L1) * (T2 ＾ L2)} is 0.603. The difference in light intensity is large and adversely affects the imaging performance.
[0019]
A second specific example according to the present invention will be described.
The second embodiment is based on the configuration of FIG. 4 and is a projection optical system having the lens data of Table 2.
[0020]
[Table 2]

The maximum image height Y of the projection exposure apparatus is a value unique to the projection exposure apparatus, and is 13.73 mm. The radius of curvature (G27-R2) of the lens surface closest to the substrate is 42.186 mm. Therefore, the value of R / Y is 3.073.
Further, the transmittance T1 of light per 1 cm of the immersion liquid used in this projection exposure apparatus is 0.90, the short distance U1 of the optical paths in the liquid is 0.764 cm, and the long distance L1 is 1.377 cm. The transmittance T2 of light per cm of the lens glass material having a high absorptance in the projection optical system is 0.98, and the optical path of the light ray which follows the optical path of U1 in the projection optical system and passes through the lens is calculated. Is a distance U2 of 4.315 cm, and a distance L2 of an optical path of a light ray that follows the optical path of L1 in the projection optical system and passes through the lens is 1.146 cm.
Therefore, the value of {1- (T1 @ U1) * (T2 @ U2)} / {1- (T1 @ L1) * (T2 @ L2)} is 0.997, which adversely affects the imaging performance. There is no.
[0021]
Here, as a comparison, when a lens having such a high absorptance is not inserted, that is, when a lens determined to have a high absorptance transmits light almost without absorbing light like other lenses, approximately Since T2 can be considered to be 1, the value of {1- (T1 ＾ U1) * (T2 ＾ U2)} / {1- (T1 ＾ L1) * (T2 ＾ L2)} is 0.573. The difference in light intensity is large and adversely affects the imaging performance.
[0022]
According to the present invention, it is possible to provide a projection exposure apparatus capable of forming an image without deteriorating aberrations and image forming performance even with an immersion exposure apparatus.
In particular, when the liquid used for immersion absorbs light, deterioration of the imaging performance can be avoided, and a desired fine pattern can be accurately printed.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an immersion projection exposure apparatus.
FIG. 2 is a configuration diagram of a part to be immersed in the immersion projection exposure apparatus.
FIG. 3 is a configuration diagram of an optical system of the projection exposure apparatus according to the first embodiment of the present invention.
FIG. 4 is a configuration diagram of an optical system of a projection exposure apparatus according to a second embodiment of the present invention.
[Explanation of symbols]
Reference Signs List 1 light source 2 illumination optical system 3 reticle 4 reticle stage 5 projection optical system 6 liquid blocking plate 7 wafer stage 8 wafer 8a ..Image plane 9 ... Lens A on the wafer side of the projection optical system ... Light rays B ... liquid

Claims (5)

A projection optical system for transferring a pattern drawn on the original to a photosensitive surface of the substrate, and a predetermined liquid is supplied to a space between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate. In a projection exposure apparatus which is formed so as to be capable of being immersed and inserted, when the radius of curvature of the lens surface closest to the substrate of the projection optical system is R, and the maximum image height projected on the photosensitive surface of the substrate is Y, ,
1 <R / Y <7
A projection exposure apparatus formed to satisfy the following. A projection optical system for transferring a pattern drawn on the original to a photosensitive surface of the substrate, and a predetermined liquid is supplied to a space between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate. In a projection exposure apparatus which is formed so as to be capable of being immersed and inserted, all or a part of the glass material used for the projection optical system is formed of a glass material having light absorption, and one of the light beams transmitted through the liquid absorbs the light absorbing material. Wherein the distance through which the light passes through the liquid is shorter than the distance through which the other light having a longer distance in the liquid than the one light passes through the liquid-absorbing glass. Exposure equipment. A projection optical system for transferring a pattern drawn on the original to a photosensitive surface of the substrate, and a predetermined liquid is supplied to a space between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate. In the projection exposure apparatus formed so as to be immersed to be inserted, of the optical path for forming an image at the position where the maximum image height is projected on the photosensitive surface of the substrate, the optical path closest to the substrate of the projection optical system The optical path having the shortest optical path length between the lens surface and the photosensitive surface of the substrate is KU, where KU is the light absorptivity of light in the optical path in the projection optical system that travels from the original to the substrate. The optical path having the longest optical path length between the lens surface closest to the substrate and the photosensitive surface of the substrate has an absorption rate KL in the optical path in the projection optical system that runs from the original to the substrate. Complete glass materials used in projection optical systems Alternatively, a part of the light-absorbing glass material is used, and a light ray that follows an optical path having a short distance to penetrate the liquid increases the distance that the light passes through the light-absorbing glass material, and the distance that the light passes through the liquid. By reducing the distance that light rays that follow a long optical path penetrate the glass material having the light absorption,
0.8 <KU / KL <1.25
A projection exposure apparatus formed to satisfy the following. 4. The projection exposure apparatus according to claim 3, wherein a transmittance per unit of the liquid medium immersed in the space is T1, and an image is formed at a position where a maximum image height is projected on a photosensitive surface of the substrate. In the optical path for imaging, the optical path length between the lens surface of the projection optical system closest to the substrate and the photosensitive surface of the substrate is U1, the distance of the shortest optical path is L1, and the distance of the longest optical path is L1. The transmittance per unit of the glass material having light absorption in the projection optical system is defined as T2, the length of a light ray following the shortest optical path distance U1 passing through the glass material is defined as U2, and the distance of the longest optical path is defined as U2. Assuming that the length of the light ray following L1 passing through the glass material is L2, the power is represented by ＾.
0.8 <{1- (T1 @ U1) * (T2 @ U2)} / {1- (T1 @ L1) * (T2 @ L2)} <1.25
A projection exposure apparatus formed to satisfy the following. A method of exposing using the projection exposure apparatus according to any one of claims 1 to 4, wherein an illumination step of illuminating the original with predetermined exposure light, and a step of irradiating the original with the projection optical system. An exposing step of exposing a pattern image on a photosensitive surface of the substrate.

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