CN101216682B

CN101216682B - Projection optical system, exposure apparatus, and exposure method

Info

Publication number: CN101216682B
Application number: CN200710306118.7A
Authority: CN
Inventors: 大村泰弘
Original assignee: Nikon Corp
Current assignee: Nikon Corp
Priority date: 2003-05-06
Filing date: 2004-05-06
Publication date: 2020-09-01
Anticipated expiration: 2024-05-06
Also published as: CN101295140A; CN101216682A; CN100405119C; CN101295140B; CN101216598A; CN101216598B; CN101216599A; CN1784623A; CN101216599B; CN101216600B; CN101216600A; JP2004333761A

Abstract

The invention provides a comparatively small projection optical system which can excellently correct chromatic aberration, image field curvature and other aberrations, has excellent imaging performance, can excellently inhibit reflection loss on an optical surface and can ensure a large effective image side numerical aperture, and is a reflection and refraction type projection optical system which forms a reduced image of a 1 st surface (R) on a 2 nd surface (W). The projection optical system includes at least 2 mirrors (CM1, CM2), a boundary lens (Lb) having a positive refractive power on the 1 st surface, and a medium (Lm) having a refractive index larger than 1.1 and filling an optical path between the boundary lens and the 2 nd surface. All the transmission members and all the reflection members having refractive power constituting the projection optical system are arranged along a single optical Axis (AX), and have an effective imaging region of a predetermined shape not including the optical axis.

Description

Projection optical system, exposure apparatus, and exposure method

This application is a divisional application entitled "projection optical system, exposure apparatus, and exposure method" with application number 200480012069.0, and application date 2004, 5/6.

Technical Field

The present invention relates to a catadioptric projection optical system, an exposure apparatus, and an exposure method, and more particularly to a catadioptric projection optical system suitable for high resolution in an exposure apparatus used for manufacturing a semiconductor device, a liquid crystal display device, or the like by photolithography.

Background

In a photolithography process for manufacturing a semiconductor device or the like, a projection exposure apparatus is used which exposes a pattern image of a mask (or a reticle) onto a wafer (or a glass plate or the like) coated with a resist or the like through a projection optical system. Further, with the increase in the integration of semiconductor devices and the like, the resolution (resolution) required for the projection optical system of the projection exposure apparatus is increasing.

As a result, in order to satisfy the requirements for resolving power of the projection optical system, it is necessary to shorten the wavelength λ of the illumination light (exposure light) and increase the image-side numerical aperture NA of the projection optical system. Specifically, the resolution of the projection optical system is represented by k · λ/NA (k is a processing coefficient). The image-side numerical aperture NA is represented by n · sin θ, where n is a refractive index of a medium (usually, a gas such as air) between the projection optical system and the image plane, and θ is a maximum incident angle to the image plane.

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

However, when this technique is applied to a general refractive projection optical system, there is a problem that it is difficult to satisfactorily correct chromatic aberration and to satisfactorily correct field curvature while satisfying Petzval (Petzval) conditions, and an increase in size of the optical system is unavoidable. Further, there is a problem that it is difficult to satisfactorily suppress reflection loss on the optical surface and to secure a large effective image-side numerical aperture.

Disclosure of Invention

The object of the present invention is to provide a relatively small projection optical system which can satisfactorily correct chromatic aberration and image plane curvature and has excellent imaging performance, and which can satisfactorily suppress reflection loss on an optical surface and ensure a large effective image-side numerical aperture.

In addition, in the case of a projection optical system including only a reflective optical member and a projection optical system including a combination of a refractive optical member and a reflective optical member, when the numerical aperture is increased, it is difficult to separate the optical paths of the light beam incident on the reflective optical member and the light beam reflected by the reflective optical member, and it is impossible to avoid an increase in the size of the reflective optical member, that is, an increase in the size of the projection optical system.

In order to simplify the manufacturing and the mutual adjustment of the optical members, it is preferable to configure the catadioptric projection optical system with a single optical axis, but even in this case, if the numerical aperture is increased, it is difficult to separate the optical paths of the light beam incident on the reflective optical member and the light beam reflected by the reflective optical member, and the projection optical system is increased in size.

The 2 nd object of the present invention is to obtain a large numerical aperture without enlarging an optical member constituting a catadioptric projection optical system.

It is another object of the present invention to provide an exposure apparatus and an exposure method which can transfer and expose a fine pattern with high accuracy by a projection optical system having excellent image forming performance, a large effective image-side numerical aperture, and high resolution.

To achieve the above object 1, the projection optical system according to the 1 st aspect of the present invention is a catadioptric projection optical system in which a reduced image of the 1 st surface is formed on the 2 nd surface,

the method is characterized in that:

the projection optical system comprises at least 2 pieces of reflecting mirrors, and a boundary lens with a positive refractive power on the surface of the 1 st surface side;

when the refractive index of the environment in the optical path of the projection optical system is 1, the optical path between the boundary lens and the 2 nd surface is filled with a medium having a refractive index larger than 1.1;

all the transmission members and all the reflection members having refractive power constituting the projection optical system are arranged along a single optical axis;

the projection optical system has an effective imaging area of a predetermined shape that does not include the optical axis.

In order to achieve the above-mentioned object 2, the projection optical system according to the 2 nd aspect of the present invention is a catadioptric projection optical system in which an image of the 1 st surface is formed on the 2 nd surface,

it is characterized by comprising:

a 1 st imaging optical system including 2 mirrors and forming an intermediate image of the 1 st surface,

a 2 nd imaging optical system for forming the intermediate image on the 2 nd surface;

wherein the content of the first and second substances,

the 2 nd imaging optical system has, in order of light passing from the intermediate image side, a

A 1 st field reflector with a concave shape,

A 2 nd field mirror,

A 1 st lens group having at least 2 negative lenses and having a negative refractive power,

A 2 nd lens group having a positive refractive power,

An aperture diaphragm,

And a 3 rd lens having a positive refractive power.

In order to achieve the above-mentioned 2 nd object, the projection optical system according to the 3 rd aspect of the present invention is a catadioptric projection optical system in which an image of the 1 st surface is formed on the 2 nd surface,

it is characterized by comprising:

a 1 st group, which is disposed in an optical path between the 1 st surface and the 2 nd surface and has a positive refractive power,

A group 2 disposed in the optical path between the 1 st surface and the 2 nd surface and having at least 4 reflection mirrors,

A 3 rd group including at least 2 negative lenses and having a negative refractive power, disposed in an optical path between the 2 nd group and the 2 nd surface,

A 4 th group which is arranged in an optical path between the 3 rd group and the 2 nd surface, contains at least 3 positive lenses, and has a positive refractive power;

wherein the content of the first and second substances,

the 1 st intermediate image is formed in the 2 nd group, and the aperture stop is provided in the 4 th group.

In order to achieve the above-mentioned 2 nd object, a projection optical system according to the 4 th aspect of the present invention is a catadioptric projection optical system in which an image of the 1 st surface is formed on the 2 nd surface, comprising:

a 1 st imaging optical system including at least 6 reflection mirrors and forming a 1 st intermediate image and a 2 nd intermediate image of the 1 st surface;

and a 2 nd imaging optical system for relaying the 2 nd intermediate image on the 2 nd surface.

In order to achieve the above-mentioned object 3, an exposure apparatus according to claim 5 of the present invention is an exposure apparatus for exposing a pattern formed on a mask onto a photosensitive substrate,

it is characterized by comprising:

an illumination system for illuminating the mask set on the 1 st surface;

and a projection optical system for forming the pattern image formed on the mask on the photosensitive substrate set on the 2 nd surface in the certain mode.

Further, to achieve the above-mentioned object 3, the exposure method according to the 6 th aspect of the present invention is an exposure method for exposing a pattern formed on a mask onto a photosensitive substrate,

it is characterized by comprising:

an illumination step of illuminating the mask on which the predetermined pattern is formed,

an exposure step of exposing the pattern of the mask disposed on the 1 st surface to the photosensitive substrate disposed on the 2 nd surface by using the projection optical system according to any one of claims 1 to 44.

Drawings

Fig. 1 is a schematic diagram showing the configuration of an exposure apparatus according to an embodiment of the present invention.

Fig. 2 is a diagram showing a positional relationship between the circular arc-shaped effective exposure region formed on the wafer and the optical axis in the present embodiment.

Fig. 3 is a schematic view showing a structure between a boundary lens and a wafer according to example 1 of the present embodiment.

Fig. 4 is a schematic view showing a structure between a boundary lens and a wafer according to example 2 of the present embodiment.

Fig. 5 shows a lens configuration of a projection optical system according to embodiment 1 of the present invention.

Fig. 6 shows the transverse aberration in embodiment 1.

Fig. 7 shows a lens structure of a projection optical system according to embodiment 2 of the present embodiment.

Fig. 8 shows the transverse aberration for the 2 nd embodiment.

Fig. 9 shows a lens structure of a catadioptric projection optical system according to embodiment 3.

Fig. 10 shows a lens structure of a catadioptric projection optical system according to embodiment 4.

FIG. 11 shows an exposure area on a wafer according to embodiments 3 and 4.

Fig. 12 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction with respect to the catadioptric projection optical system of embodiment 3.

Fig. 13 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction in the catadioptric projection optical system according to embodiment 4.

Fig. 14 shows a lens structure of a catadioptric projection optical system according to embodiment 5.

Fig. 15 shows a lens structure of a catadioptric projection optical system according to embodiment 6.

Fig. 16 shows a lens structure of a catadioptric projection optical system according to embodiment 7.

Fig. 17 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction with respect to the catadioptric projection optical system of embodiment 5.

Fig. 18 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction in the catadioptric projection optical system according to embodiment 6.

Fig. 19 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction in the catadioptric projection optical system according to embodiment 7.

Fig. 20 is a flowchart showing a method for obtaining a semiconductor device as a microdevice.

Fig. 21 is a flowchart showing a method for obtaining a liquid crystal display element as a microdevice.

Description of the symbols

1: liquid supply device

2: liquid recovery device

3: supply pipe

4: supply nozzle

7: top end surface of lens

20: recovery device

50: liquid, method for producing the same and use thereof

51: z carrying platform

52: XY stage

53: base seat

54: movable mirror

55: laser interferometer

56: space(s)

60: lens and lens assembly

100: light source

110: s-polarized light conversion element

a. b: position of

AR: aberration correction area

AS, AS1, AS 2: aperture diaphragm

AX, AX1, AX 2: optical axis

CONT: control device

CM 1: no. 1 concave reflector

CM 2: no. 2 concave reflector

EL: exposure light

ER: effective exposure area

EX: exposure device

G1, G3, G5: 1 st imaging optical system

G2, G4, G6: 2 nd imaging optical system

G11, G21, G22, G23, G31, G41, G42, G43: lens group

IL: illumination optical system

L1: parallel plane board

L3, L7, L9, L11, L12, L22, L23, L27, L29, L210, L213: biconvex lens

L2, L5, L6, L13, L24, L25, L28, L30: negative meniscus lens

L4, L8, L10, L13, L14, L15, L16, L17, L21, L22, L23, L27, L29, L31, L32, L33, L34, L35, L211, L212, L214, L215, L216: positive meniscus lens

L25, L26: biconcave lens

L18, L36, L217: plano-convex lens

Lb: boundary lens

Lp, L21: parallel plane board

Lm: medium

M1, M2, M3, M4: reflecting mirror

M22, M24: convex reflector

M21, M23: concave reflector

PK: lens barrel

PL, PL1, PL2, PL 3: projection optical system

R, R1, R2, R3: grating

Ro: outer diameter

Ri: inner diameter

RST: grating carrying platform

RSTD: grating carrying platform driving device

Sb: grating side surface of boundary lens

W: wafer

WST: wafer carrying platform

WSTD: wafer stage driving device

WT: wafer holder carrying platform

Detailed Description

The projection optical system according to claim 1 of the present invention is configured such that a medium having a refractive index larger than 1.1 is interposed in an optical path between the boundary lens and the image plane (2 nd plane), thereby increasing the image-side numerical aperture NA. Incidentally, in "Resolution Enhancement of 157-nm lithagyby precision imaging" published by Mr. Switkes and M.Rothschild in "Massachusetts Institute of technology" on "SPIE 2002 Microlithagraphy", perfluoropolyethers (trade name of 3M company, USA) and Deionized Water (Deionized Water) are given as candidates as media having a desired transmittance for light having a wavelength of 200nm or less.

In the projection optical system according to aspect 1 of the present invention, by applying a positive refractive power to the optical surface on the object side (1 st surface side) of the boundary lens, reflection loss on the optical surface can be reduced, and a large effective image-side numerical aperture can be ensured. In this way, in an optical system having a high refractive index material such as a liquid as a medium on the image side, the effective image side numerical aperture can be increased to 1.0 or more, and the resolution can be improved. However, when the projection magnification is constant, the object-side numerical aperture increases as the image-side numerical aperture increases, and therefore, if the projection optical system is configured only by the refractive member, it is difficult to satisfy the petzval condition, and the optical system cannot be increased in size.

Therefore, the projection optical system according to the 1 st aspect of the present invention is a catadioptric optical system including at least 2 mirrors, all of the transmissive members and all of the reflective members having refractive power (power) arranged along a single optical axis, and having an effective imaging region of a predetermined shape without including the optical axis. In this type of projection optical system, the chromatic aberration can be favorably corrected by the action of, for example, a concave mirror, and the curvature of the image plane can be favorably corrected while easily satisfying the petzval condition, and the optical system can be miniaturized.

In the projection optical system of this type, since all the transmission members (such as lenses) and all the reflection members (such as concave mirrors) having power are arranged along a single optical axis, the manufacturing difficulty is remarkably low and it is preferable to configure the optical system in a plural-axis manner in which the optical members are arranged along plural optical axes. However, in the case of a single-axis configuration in which the optical member is arranged along a single optical axis, it tends to be difficult to correct chromatic aberration well, but the problem of chromatic aberration correction can be overcome by using laser light having a narrow spectrum band, such as ArF laser light.

As described above, according to the first aspect of the present invention, it is possible to realize a relatively small projection optical system which can satisfactorily correct chromatic aberration and image plane curvature and has excellent imaging performance, and which can satisfactorily suppress reflection loss on an optical surface and ensure a large effective image-side numerical aperture. Therefore, with the exposure apparatus and the exposure method using the projection optical system according to aspect 1 of the present invention, a fine pattern can be transferred and exposed with high accuracy by the projection optical system having excellent image forming performance, a large effective image-side numerical aperture, and a high resolution.

In the 1 st aspect of the present invention, it is preferable that the projection optical system has a configuration in which the projection optical system has an even number of mirrors, that is, a configuration in which the 1 st surface image is formed on the 2 nd surface by an even number of reflections. With this configuration, when applied to, for example, an exposure apparatus and an exposure method, a surface image (an erect image or an inverted image) is formed on a wafer instead of a back surface image of a mask pattern, and therefore, a normal mask (a reticle) can be used as in the case of an exposure apparatus equipped with a refractive projection optical system.

In the 1 st aspect of the present invention, it is preferable that the optical imaging system includes a 1 st imaging optical system including 2 mirrors and forming an intermediate image of the 1 st surface and a 2 nd imaging optical system forming the intermediate image on the 2 nd surface, and the 2 nd imaging optical system has a 1 st field mirror having a concave shape, a 2 nd field mirror, a 1 st lens group having at least 2 negative lenses and having a negative refractive power, a 2 nd lens group having a positive refractive power, an aperture stop, and a 3 rd lens group having a positive refractive power in order of light beam passage from the intermediate image side.

With this configuration, since the intermediate image of the 1 st surface is formed in the 1 st image forming optical system, even when the numerical aperture of the catadioptric projection optical system is increased, the optical path separation of the light flux directed to the 1 st surface side and the light flux directed to the 2 nd surface side can be easily and reliably performed. Further, since the 1 st lens group having a negative refractive power is included in the 2 nd imaging optical system, the total length of the catadioptric projection optical system can be shortened, and adjustment for satisfying the petzval condition can be easily performed. In addition, the 1 st lens group alleviates the difference caused by the difference of the view angles of the light beams expanded by the 1 st field mirror, and suppresses the generation of aberration. Therefore, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, excellent imaging performance can be obtained over the entire exposure region.

In the above configuration, it is preferable that the 1 st imaging optical system includes a 4 th lens group having a positive refractive power, a negative lens, a concave mirror, and an optical path splitting mirror, and light traveling in the 1 st imaging optical system is transmitted through the 4 th lens group and the negative lens, reflected by the concave mirror, guided to the optical path splitting mirror through the negative lens again, and reflected by the optical path splitting mirror is reflected by the 1 st field mirror and the 2 nd field mirror, and then directly incident on the 1 st lens group in the 2 nd imaging optical system.

With this configuration, the 1 st imaging optical system includes the 4 th lens group having a positive refractive power, and therefore the 1 st surface side can be telecentric. Further, since the 1 st imaging optical system has the negative lens and the concave reflecting mirror, adjustment for satisfying the petzval condition can be easily performed by adjusting the negative lens and the concave reflecting mirror.

In the 1 st aspect of the present invention, it is preferable that the optical system includes a 1 st imaging optical system having at least 6 mirrors and forming a 1 st intermediate image and a 2 nd intermediate image of the 1 st surface, and a 2 nd imaging optical system for relaying the 2 nd intermediate image on the 2 nd surface.

With this configuration, since at least 6 mirrors are included, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, the 1 st intermediate image and the 2 nd intermediate image can be formed without increasing the total length of the catadioptric projection optical system, and good imaging performance can be obtained in the entire exposure area.

In the above configuration, it is preferable that the 1 st intermediate image is formed between the mirror on which the 2 nd bit of the light emitted from the 1 st surface enters and the mirror on which the 4 th bit of the light emitted from the 1 st surface enters, among the at least 6 mirrors included in the 1 st imaging optical system.

With this configuration, the 1 st intermediate image is formed between the mirror on which the 2 nd bit of the light emitted from the 1 st surface enters and the mirror on which the 4 th bit of the light emitted from the 1 st surface enters. Therefore, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, the optical paths of the light flux directed to the 1 st surface side and the light flux directed to the 2 nd surface side can be easily and reliably separated, and good imaging performance can be obtained in the entire exposure region.

However, in order to configure the catadioptric projection optical system according to claim 1 of the present invention with a single optical axis, it is necessary to form an intermediate image in the vicinity of the pupil position, and therefore the projection optical system is preferably a re-imaging optical system. Further, in order to form an intermediate image near the pupil position of the 1 st image and to separate the optical paths and avoid mechanical interference between optical members, it is necessary to reduce the pupil diameter of the 1 st image as much as possible even when the object-side numerical aperture is increased, and therefore, it is preferable that the 1 st image forming optical system having a small numerical aperture be a catadioptric optical system.

Therefore, in the 1 st aspect of the present invention, it is preferable that the projection optical system is configured by a 1 st imaging optical system including at least 2 mirrors and configured to form an intermediate image on a 1 st surface, and a 2 nd imaging optical system configured to form a final image on a 2 nd surface based on a light flux from the intermediate image. In this case, specifically, the 1 st imaging optical system can be configured by the 1 st lens group of positive refractive power, the 1 st mirror disposed in the optical path between the 1 st lens group and the intermediate image, and the 2 nd mirror disposed in the optical path between the 1 st mirror and the intermediate image.

The 1 st mirror is preferably a concave mirror disposed in the vicinity of the pupil plane of the 1 st imaging optical system, and at least 1 negative lens is preferably disposed in the optical path to and from the concave mirror. By arranging the negative lens in the reciprocal optical path forming the concave mirror in the 1 st imaging optical system as described above, it is possible to easily satisfy the petzval condition, correct the field curvature well, and correct the chromatic aberration well.

Further, although it is preferable to dispose the negative lens in the optical path of the round trip near the pupil position, since the pupil diameter of the 1 st image must be reduced as much as possible, the effective diameter of the negative lens is also reduced, and thus the energy density (i.e., energy per unit area/unit pulse) tends to be increased in the negative lens. Therefore, when the negative lens is formed of quartz, local refractive index changes due to volume shrinkage, i.e., compaction, are likely to occur upon irradiation with laser light, and the imaging performance of the projection optical system is degraded.

Similarly, the boundary lens disposed adjacent to the image plane has a small effective diameter and is likely to have a high energy density. Therefore, when the boundary lens is formed using quartz, compaction is easily generated to deteriorate imaging performance. In the 1 st aspect of the present invention, the negative lens disposed in the optical path of reciprocation formed by the concave mirror in the 1 st imaging optical system and the boundary lens disposed adjacent to the image plane in the 2 nd imaging optical system are made of fluorite, whereby the deterioration of imaging performance due to compaction can be avoided.

In the 1 st aspect of the present invention, it is preferable that the following conditional expression (1) is satisfied. In the conditional expression (1), F1 is the focal length of the 1 st lens group, and Y is₀The maximum image height on the 2 nd plane.

5＜F1/Y₀＜15 (1)

If the upper limit of the conditional expression (1) is exceeded, the pupil diameter of the 1 st image becomes too large, and it becomes difficult to avoid mechanical interference between the optical members as described above, which is not preferable. On the other hand, if the value is lower than the lower limit value of the conditional expression (1), a difference in angle of incident light to the mirror due to the height of the object (difference in viewing angle of the screen) is large, and it is difficult to correct aberrations such as coma and curvature of field, which is not preferable. In order to more satisfactorily exhibit the effects of the present invention, it is more preferable to limit the upper limit value of the conditional expression (1) to 13 and the lower limit value thereof to 7.

In the 1 st aspect of the present invention, it is preferable that the 1 st lens group has at least 2 positive lenses. With this configuration, the positive refractive power of the 1 st lens group can be set large, the conditional expression (1) can be easily satisfied, and coma aberration, distortion aberration, non-point aberration, and the like can be corrected well.

Further, it is difficult to manufacture a mirror having high reflectance and high durability, and a large number of reflecting surfaces cause light quantity loss. Therefore, in the 1 st aspect of the present invention, when the projection optical system is applied to, for example, an exposure apparatus and an exposure method, the 2 nd imaging optical system is preferably a refractive optical system composed of only a plurality of transmissive members from the viewpoint of improving productivity.

Further, fluorite is a crystalline material having intrinsic birefringence, and a transmissive material made of fluorite has a large influence on birefringence particularly of light having a wavelength of 200nm or less. Therefore, in an optical system including a fluorite transmissive member, it is necessary to suppress the deterioration of image forming performance due to birefringence by combining fluorite transmissive members having different crystal axis orientations, but even if such measures are taken, the deterioration of performance due to birefringence cannot be completely suppressed.

Further, it is known that the refractive index distribution inside fluorite has a high frequency component, and a difference in refractive index containing the frequency component causes generation of flare, and tends to lower the imaging performance of the projection optical system, so it is preferable to reduce the use of fluorite as much as possible. Therefore, in the present invention, in order to reduce the use of fluorite as much as possible, it is preferable that 70% or more of the transmission members constituting the 2 nd imaging optical system as a refractive optical system be formed of quartz.

In the 1 st aspect of the present invention, it is preferable that the effective imaging region has an arc shape and satisfies the following conditional expression (2). In the conditional expression (2), R is a radius of curvature of a circular arc for defining an effective imaging region, and Y is₀The maximum image height on the 2 nd plane as described above.

1.05＜R/Y₀＜12 (12)

In the 1 st aspect of the present invention, the effective imaging region having the circular arc shape not including the optical axis makes it possible to easily perform optical path separation while avoiding an increase in size of the optical system. However, when applied to, for example, an exposure apparatus and an exposure method, it is difficult to uniformly illuminate an arc-shaped illumination region on a mask. Therefore, a method of limiting a rectangular illumination light flux corresponding to a rectangular area including an arc-shaped area by a field stop having an arc-shaped aperture portion (light transmission portion) can be adopted. In this case, in order to suppress the loss of the light amount of the field stop, it is necessary to make the size R of the curvature radius of the circular arc defining the effective imaging area as large as possible.

That is, if the value is less than the lower limit of the conditional expression (2), the value R of the radius of curvature is too small, which is not preferable because the light flux loss of the field stop is increased and the productivity is lowered due to the low illumination efficiency. On the other hand, if the upper limit of the conditional expression (2) is exceeded, the size R of the curvature radius becomes too large, and if an effective imaging region of a required width is to be secured in order to shorten the excess length in the scanning exposure, the necessary aberration correction region becomes large, which is undesirable because the optical system becomes large in size. In order to more satisfactorily exhibit the effects of the present invention, it is more preferable to set the upper limit of conditional expression (2) to 8 and the lower limit thereof to 1.07.

In the catadioptric projection optical system of the above type, even when the optical path to the image plane (2 nd plane) is not filled with a medium such as a liquid, the productivity is prevented from being lowered due to the lowering of the illumination efficiency and the optical system is prevented from being enlarged due to the increase of the necessary aberration correction area by satisfying the conditional expression (2). When the projection optical system of the present invention is applied to an exposure apparatus and an exposure method, it is preferable to use ArF laser light (wavelength 193.306nm), for example, as the exposure light, in consideration of the transmittance of a medium (liquid or the like) filled between the boundary lens and the image plane and the degree of narrowing of the laser light.

The projection optical system according to the 2 nd aspect of the present invention is a catadioptric projection optical system for forming an image of the 1 st surface on the 2 nd surface, comprising a 1 st imaging optical system including 2 mirrors and forming an intermediate image of the 1 st surface, and a 2 nd imaging optical system for forming the intermediate image on the 2 nd surface, wherein the 2 nd imaging optical system includes, in order of light beam passage from the intermediate image side, a 1 st field mirror having a concave shape, a 2 nd field mirror, a 1 st lens group having at least 2 negative lenses and having a negative refractive power, a 2 nd lens group having a positive refractive power, an aperture stop, and a 3 rd lens group having a positive refractive power.

In the projection optical system according to the 2 nd aspect of the present invention, it is preferable that the 1 st imaging optical system includes a 4 th lens group having a positive refractive power, a negative lens, a concave mirror, and an optical path separating mirror, and light traveling through the 1 st imaging optical system is transmitted through the 4 th lens group and the negative lens, reflected by the concave mirror, and guided to the optical path separating mirror again through the negative lens, and the light reflected by the optical path separating mirror is reflected by the 1 st field mirror and the 2 nd field mirror, and then directly enters the 1 st lens group in the 2 nd imaging optical system.

In the projection optical system according to claim 2 of the present invention, it is preferable that the 1 st field mirror causes the light incident on the 1 st field mirror to be bent in a direction toward the optical axis of the catadioptric projection optical system and to be emitted.

In the projection optical system according to claim 2 of the present invention, it is preferable that the 2 nd field mirror has a convex shape.

With these configurations, the light beam incident on the 1 st field mirror is bent in the direction toward the optical axis of the catadioptric projection optical system and is output, so that the 2 nd field mirror can be downsized even when the aperture of the catadioptric projection optical system is increased. Therefore, even when the numerical apertures on the object side and the image side are increased in order to improve resolution, the optical paths of the light flux directed to the 1 st surface side and the light flux directed to the 2 nd surface side can be easily separated.

In the projection optical system according to the 2 nd aspect of the present invention, the 2 mirrors included in the 1 st imaging optical system are a concave mirror and a convex mirror in order of incidence of light from the 1 st surface, and the 2 nd field mirror included in the 2 nd imaging optical system is a convex mirror.

With this configuration, since the 2 nd field mirror included in the 1 st imaging optical system has a concave shape and a convex shape and the 2 nd field mirror has a convex shape, the light flux emitted from the 1 st imaging optical system can be easily and surely guided to the 2 nd imaging optical system.

In the projection optical system according to claim 2 of the present invention, the aperture stop is disposed between the 1 st field mirror and the 2 nd surface, and when the distance on the optical axis between the 1 st field mirror and the 2 nd surface is Ma and the distance between the 1 st surface and the 2 nd surface is L, it suffices that

0.17＜Ma/L＜0.6

The conditions of (3) are preferred.

With this configuration, Ma/L is larger than 0.17, so that mechanical interference between the 1 st field mirror and the 1 st and 2 nd lens groups can be avoided. Further, since Ma/L is smaller than 0.6, the total length of the catadioptric projection optical system can be prevented from being elongated and enlarged.

In the projection optical system according to claim 2 of the present invention, it is preferable that the 1 st lens included in the 2 nd imaging optical system includes at least 1 aspherical lens.

With this configuration, since at least 1 optical element constituting the 1 st lens group has an aspherical lens, it is possible to obtain a good image forming performance over the entire exposure region even when the numerical apertures on the object side and the image side are increased.

A projection optical system according to a 3 rd aspect of the present invention is a catadioptric projection optical system for forming an image of a 1 st surface on a 2 nd surface, comprising a 1 st group having a positive refractive power and disposed in an optical path between the 1 st surface and the 2 nd surface, a 2 nd group having at least 4 mirrors and disposed in an optical path between the 1 st group and the 2 nd surface, a 3 rd group having a negative refractive power and disposed in an optical path between the 2 nd group and the 2 nd surface and including at least 2 negative lenses, and a 4 th group having a positive refractive power and disposed in an optical path between the 3 rd group and the 2 nd surface and including at least 3 positive lenses, wherein 1 intermediate image is formed in the 2 nd group, and an aperture stop is provided in the 4 th group.

As with the projection optical system according to the 3 rd aspect of the present invention, since the intermediate image of the 1 st surface is formed in the 2 nd group, even when the numerical aperture of the catadioptric projection optical system is increased, the optical path separation of the light flux directed to the 1 st surface side and the light flux directed to the 2 nd surface side can be easily and surely performed. Further, since the 3 rd group having negative refractive power is included, the total length of the catadioptric projection optical system can be shortened, and adjustment for satisfying the petzval condition can be easily performed. Therefore, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, excellent imaging performance can be obtained over the entire exposure region.

In the projection optical system according to the 3 rd aspect of the present invention, the 2 nd group preferably has a 1 st mirror having a concave shape, a 2 nd mirror having a convex shape, a 3 rd mirror having a concave shape, and a 4 th mirror having a convex shape in order of incidence of the light from the 1 st surface.

With this configuration, since the concave mirror, the convex mirror, the concave mirror, and the convex mirror are provided in this order from the 1 st surface, the light flux emitted from the 1 st imaging optical system can be easily and accurately guided to the 2 nd imaging optical system.

In the projection optical system according to the 3 rd aspect of the present invention, the 2 nd group includes at least 1 negative lens, and the optical element closest to the 3 rd group in the optical path of the 2 nd group is preferably the 4 th mirror or a shuttle lens through which light passes 2 times.

With this configuration, since the optical element closest to the 3 rd group in the optical path of the 2 nd group is the 4 th mirror or the shuttle lens through which light passes 2 times, the adjustment for satisfying the petzval condition can be easily performed by adjusting the lens included in the 3 rd group having a negative refractive power, the 4 th mirror or the shuttle lens.

In the projection optical system according to claim 3 of the present invention, it is preferable that the 3 rd mirror bends and emits the light incident on the 3 rd mirror in a direction toward the optical axis of the catadioptric projection optical system.

With this configuration, the light beam incident on the 3 rd mirror is bent in the direction toward the optical axis of the catadioptric projection optical system and is emitted, so that the 4 th mirror can be downsized. Therefore, even when the numerical apertures on the object side and the image side are increased in order to improve the resolution, the optical paths of the light flux directed to the 1 st surface side and the light flux directed to the 2 nd surface side can be easily and reliably separated.

In the projection optical system according to claim 3 of the present invention, the aperture stop is disposed between the 3 rd mirror and the 2 nd surface, and when the distance on the optical axis between the 3 rd mirror and the 2 nd surface is Ma and the distance between the 1 st surface and the 2 nd surface is L, it suffices that

0.17＜Ma/L＜0.6

The conditions of (3) are preferred.

With this configuration, Ma/L is larger than 0.17, so that mechanical interference between the 3 rd mirror and the 2 nd and 3 rd groups can be avoided. Further, since Ma/L is smaller than 0.6, the total length of the catadioptric projection optical system can be prevented from being elongated and enlarged.

Further, in a projection optical system according to aspect 3 of the present invention, the projection optical system includes: the group 3 is provided with at least 1 aspherical lens. With this configuration, since at least 1 of the optical elements constituting the group 3 includes the aspherical lens, it is possible to obtain a good image forming performance over the entire exposure region even when the numerical apertures on the object side and the image side are increased.

The projection optical system according to the 4 th aspect of the present invention is a catadioptric projection optical system for forming an image of the 1 st surface on the 2 nd surface, and includes a 1 st imaging optical system having at least 6 mirrors and forming the 1 st intermediate image and the 2 nd intermediate image of the 1 st surface, and a 2 nd imaging optical system for relaying the 2 nd intermediate image on the 2 nd surface.

As with the projection optical system according to the 4 th aspect of the present invention, since at least 6 mirrors are included, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, the 1 st intermediate image and the 2 nd intermediate image can be formed without increasing the total length of the catadioptric projection optical system, and good imaging performance can be obtained in the entire exposure area.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that the 1 st intermediate image is formed between the mirror on which the 2 nd bit of the light emitted from the 1 st surface enters and the mirror on which the 4 th bit of the light emitted from the 1 st surface enters, among the at least 6 mirrors included in the 1 st imaging optical system.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that the 1 st imaging optical system includes a field lens group having a positive refractive power and composed of a transmissive optical element, and the at least 6 mirrors are arranged so as to continuously reflect light having passed through the field lens group.

With this configuration, since the 1 st imaging optical system includes the field lens group having a positive refractive power and including the transmissive optical element, it is possible to correct distortion or the like by the field lens group and to telecentric the 1 st surface side. Further, since no lens is disposed in the optical path between at least 6 mirrors, it is possible to easily hold each mirror while securing a region for holding each mirror. Further, since light is continuously reflected by each mirror, the petzval condition can be easily satisfied by adjusting each mirror.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that the 1 st imaging optical system includes a field lens group having a positive refractive power and composed of a transmissive optical element, and at least 1 negative lens is preferably included between the mirror on which the 1 st bit of light emitted from the 1 st surface enters and the mirror on which the 6 th bit of light emitted from the 1 st surface enters, among the at least 6 mirrors.

With this configuration, the 1 st imaging optical system includes the field lens group having positive refractive power and formed of the transmissive optical element, and thus the 1 st surface side can be telecentric. Further, since at least 1 negative lens is provided between the mirror on which the 1 st bit of light emitted from the 1 st surface enters and the mirror on which the 6 th bit of light enters, the chromatic aberration can be easily corrected by adjusting the negative lens, and the adjustment can be easily performed in a manner that satisfies the petzval condition.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that all the optical elements constituting the 2 nd imaging optical system are transmissive optical elements and that a reduced image of the 1 st surface is formed on the 2 nd surface.

With this configuration, since all the optical elements constituting the 2 nd imaging optical system are transmissive optical elements, there is no load of optical path separation. Therefore, the numerical aperture on the image side of the catadioptric projection optical system can be increased, and a reduced image with a high reduction magnification can be formed on the 2 nd surface. Further, correction of coma aberration and spherical aberration can be easily performed.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that the 2 nd imaging optical system includes a 1 st lens group having a positive refractive power, a 2 nd lens group having a negative refractive power, a 3 rd lens group having a positive refractive power, an aperture stop, and a 4 th lens group having a positive refractive power, which are arranged in order of passage of light emitted from the 1 st imaging optical system.

With this configuration, the 1 st lens group having positive refractive power, the 2 nd lens group having negative refractive power, the 3 rd lens group having positive refractive power, the aperture stop, and the 4 th lens group having positive refractive power, which constitute the 2 nd imaging optical system, advantageously function to satisfy the petzval condition. Further, the increase in the total length of the catadioptric projection optical system can be avoided.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that, among the at least 6 mirrors, a mirror disposed at a position where the light emitted from the 1 st surface is farthest from the optical axis of the catadioptric projection optical system is a concave mirror, and the aperture stop is disposed between the concave mirror and the 2 nd surface. Here, when the distance on the optical axis between the concave-shaped reflecting mirror and the 2 nd surface is Mb and the distance between the 1 st surface and the 2 nd surface is L, the following condition is satisfied

0.2＜Mb/L＜0.7

The conditions of (3) are preferably as follows.

With this configuration, since Mb/L is larger than 0.2, mechanical interference between the 1 st lens group, the 2 nd lens group, and the 3 rd lens group and the concave-shaped reflecting mirror disposed at the position farthest from the optical axis of the catadioptric projection optical system can be avoided. Furthermore, since Mb/L is smaller than 0.7, the total length of the catadioptric projection optical system can be prevented from being elongated and enlarged.

In the projection optical system according to the 4 th aspect of the present invention, it is preferable that the 2 nd lens group and the 4 th lens group have at least 1 aspherical lens.

With this configuration, at least 1 of the optical elements constituting the 2 nd lens group and the 4 th lens group has an aspherical lens, so that aberration correction can be easily performed, and an increase in the total length of the catadioptric projection optical system can be avoided. Therefore, even when the numerical apertures on the object side and the image side are increased, good imaging performance can be obtained over the entire exposure region.

In the projection optical system according to the 4 th aspect of the present invention, the catadioptric projection optical system is preferably a 3-order imaging optical system in which the 1 st intermediate image, which is an intermediate image of the 1 st surface, and the 2 nd intermediate image, which is an image of the 1 st intermediate image, are formed on the optical path between the 1 st surface and the 2 nd surface.

With this configuration, since the optical system forms an image 3 times, the 1 st intermediate image forms an inverted image of the 1 st surface, the 2 nd intermediate image forms an erect image of the 1 st surface, and the image formed on the 2 nd surface is an inverted image. Therefore, when the catadioptric projection optical system is mounted on the exposure apparatus and scanning exposure is performed on the 1 st surface and the 2 nd surface, the scanning direction of the 1 st surface and the scanning direction of the 2 nd surface can be made opposite to each other, and adjustment can be easily performed with little change in the center of gravity of the entire exposure apparatus. Further, it is possible to reduce the vibration of the catadioptric projection optical system caused by the change of the center of gravity of the entire exposure apparatus, and to obtain a good image forming performance over the entire exposure region.

The projection optical system according to any one of aspects 2 to 4 of the present invention is characterized in that: among the lenses included in the catadioptric projection optical system, the lens surface on the 1 st surface side of the lens closest to the 2 nd surface side has a positive refractive power, and a medium having a refractive index larger than 1.1 is interposed in an optical path between the lens closest to the 2 nd surface side and the 2 nd surface when the refractive index of the environment in the catadioptric projection optical system is 1.

With this configuration, since a medium having a refractive index larger than 1.1 is interposed in the optical path between the lens closest to the 2 nd surface side and the 2 nd surface, the wavelength of the exposure light in the medium is 1/n times that in the air when the refractive index of the medium is n, and thus the resolution can be improved.

In addition, it is preferable that the projection optical system according to any one of the 2 nd to 4 th aspects of the present invention is such that the optical axes of all the optical elements included in the catadioptric projection optical system and having a predetermined refractive power are substantially arranged on a single straight line, and an off-axis area of the image formed on the 2 nd surface by the catadioptric projection optical system is an off-axis area not including the optical axes.

With this configuration, since the optical axes of all the optical elements included in the catadioptric projection optical system are substantially arranged on a single straight line, ease of manufacture can be reduced and relative adjustment of the optical members can be easily performed when manufacturing the catadioptric projection optical system.

An exposure apparatus according to claim 5 of the present invention is an exposure apparatus for exposing a pattern formed on a mask to a photosensitive substrate, comprising:

an illumination system for illuminating the mask set on the 1 st surface,

A projection optical system according to any one of embodiments 1 to 4 of the present invention for forming an image of the pattern formed on the mask on the photosensitive substrate set on the 2 nd surface.

With this configuration, since the catadioptric projection optical system is compact and has a large numerical aperture, a fine pattern can be exposed on the photosensitive substrate satisfactorily.

In the exposure apparatus according to claim 5 of the present invention, it is preferable that the illumination system supplies illumination light for forming S-polarized light to the 2 nd surface. With this configuration, the contrast of an image formed on a photosensitive substrate can be improved, and a wide depth of focus (DOF) can be ensured. In particular, in the projection optical system according to the 1 st to 4 th aspects of the present invention, optical path separation can be performed without using an optical path deflecting mirror (bending mirror) having a function of deflecting an optical axis. Here, there is a high possibility that a large phase difference is generated between the P-polarized light and the S-polarized light reflected by the optical path deflecting mirror, and when the optical path deflecting mirror is used, it becomes difficult to supply the illumination light for forming the S-polarized light to the 2 nd surface due to the reflected phase difference. That is, even if polarization is generated in the circumferential direction with respect to the optical axis of the illumination optical device, the problem arises that S-polarization cannot be formed on the 2 nd surface. In contrast, such a problem is unlikely to occur in the projection optical system according to the 1 st to 4 th aspects of the present invention.

In the exposure apparatus according to claim 5 of the present invention, it is preferable that the mask and the photosensitive substrate are relatively moved in a predetermined direction with respect to the projection optical system, and the pattern of the mask is projection-exposed onto the photosensitive substrate.

An exposure method according to embodiment 6 of the present invention is an exposure method for exposing a pattern formed on a mask to a photosensitive substrate, the method including: an illumination step of illuminating a mask on which a set pattern is formed, and an exposure step of exposing the pattern of the mask arranged on the 1 st surface to the photosensitive substrate arranged on the 2 nd surface by using the projection optical system according to any one of the 1 st to 4 th aspects of the present invention.

With this configuration, since exposure is performed by an exposure apparatus including a simple catadioptric projection optical system having a large numerical aperture, a fine pattern can be exposed favorably.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a schematic configuration diagram of an embodiment of an exposure apparatus according to the present invention.

In fig. 1, exposure apparatus EX includes a reticle stage RST supporting a reticle R (mask), a wafer stage WST supporting a wafer W as a substrate, an illumination optical system IL illuminating a reticle R supported by reticle stage RST with exposure light EL, a projection optical system PL projecting and exposing a pattern image of reticle R illuminated with exposure light EL onto wafer W supported by wafer stage WST, a liquid supply apparatus 1 supplying liquid 50 onto wafer W, a recovery apparatus 20 recovering liquid 50 flowing out to the outside of wafer W, and a control apparatus CONT controlling the operation of exposure apparatus EX as a whole.

Here, in the present embodiment, a case where a scanning type exposure apparatus (so-called a sequential scanning type exposure apparatus) that moves the reticle R and the wafer W in synchronization with each other in the scanning direction and exposes the pattern formed on the reticle R to the wafer W is used as the exposure apparatus EX will be described as an example. In the following description, a direction coincident with the optical axis AX of the projection optical system PL is defined as a Z-axis direction, a synchronous moving direction (scanning direction) of the reticle R and the wafer W in a plane perpendicular to the Z-axis direction is defined as an X-axis direction, and a direction (non-scanning direction) perpendicular to the Z-axis direction and the Y-axis direction is defined as a Y-axis direction. The directions around the X, Y and Z axes are referred to as θ X, θ Y and θ Z directions, respectively. The wafer described here includes a semiconductor wafer coated with a photoresist, and the grating includes a mask for forming an element pattern having an enlarged, reduced, or equi-multiplied projection on the wafer W.

The illumination optical system IL illuminates the grating R supported on the grating stage RST with exposure light EL based on exposure light emitted from the light source 100 for supplying illumination light in the ultraviolet region. The illumination optical system IL includes a light integrator for uniformizing the illuminance of the light beam emitted from the light source 100, a condenser lens for condensing the exposure light EL from the light integrator, a relay lens system, a variable field stop for setting an illumination region on the grating R by the exposure light EL to a slit shape, and the like. Here, the illumination optical system IL includes an S-polarization conversion element 110 for converting linearly polarized light from the light source 100 into polarized light forming S-polarization with respect to the grating R (wafer W) substantially without light quantity loss. As such an S-polarization conversion element, for example, japanese patent No. 3246615 discloses it.

The set illumination region on the grating R is illuminated with exposure light EL having a uniform illuminance distribution by the illumination optical system IL. As the exposure light EL emitted from the illumination optical system IL, for example, deep ultraviolet light (DUV light) such as glow light (g-line, h-line, i-line) in the ultraviolet region emitted from a mercury lamp and KrF excimer laser light (wavelength 248nm), vacuum ultraviolet light (VUV light) such as ArF excimer laser light (wavelength 193nm) and F2 laser light (wavelength 157nm), and the like can be used. In the present embodiment, ArF exciplex laser light is used.

Grating stage RST supports grating R, and is movable in 2 dimensions in a plane perpendicular to optical axis AX of projection optical system PL, that is, in the XY plane, and is slightly rotatable in the θ Z direction. Grating stage RST is driven by grating stage driving device RSTD such as a linear motor. The grating stage driving device RSTD is controlled by the control device CONT. The 2-dimensional directional position and the rotation angle of the grating R on the grating stage RST are measured in real time by the laser interferometer, and the measurement results are output to the control device CONT. The control device CONT performs positioning of the grating R supported by the grating stage RST by driving the grating stage driving device RSTD based on the measurement result of the laser interferometer.

The projection optical system PL performs projection exposure of the pattern of the grating R on the wafer W at a set projection magnification β, and is composed of a plurality of optical elements (lenses) supported by a barrel PK as a metal member. In the present embodiment, the projection optical system PL is a reduction system having a projection magnification β of, for example, 1/4 or 1/5. The projection optical system PL may be either an equal magnification system or an expansion system. Further, on the tip side (wafer W side) of the projection optical system PL of the present embodiment, the optical element (lens) 60 is exposed from the barrel PK. The optical element 60 is detachably (replaceably) provided to the barrel PK.

Wafer stage WST supports wafer W, and includes Z stage 51 for holding wafer W by a wafer holder, XY stage 52 for supporting Z stage 51, and base 53 for supporting XY stage 52. Wafer stage WST is driven by a wafer stage driving device WSTD such as a linear motor. Wafer stage driving apparatus WSTD is controlled by control apparatus CONT. By driving the Z stage 51, the position (focus position) in the Z axis direction and the positions in the θ X and θ Y directions of the wafer W held by the Z stage 51 are controlled. Further, by driving the XYZ stage 52, the XY-directional position of the wafer W (the position in the direction substantially parallel to the image plane of the projection optical system PL) can be controlled. That is, Z stage 51 controls the focus position and tilt angle of wafer W, and incorporates the surface of wafer W into the image plane of projection optical system PL in an autofocus system and an automatic balance system, and XY stage 52 performs positioning of wafer W in the X-axis direction and the Y-axis direction. It is needless to say that the Z stage and the XY stage may be integrally provided.

A movable mirror 54 is provided on wafer stage WST (Z stage 51). Further, a laser interferometer 55 is provided at a position opposed to the moving mirror 54. The 2-dimensional directional position and the rotation angle of the wafer W on the wafer stage WST are measured in real time by the laser interferometer 55, and the measurement results are output to the control unit CONT. The control device CONT positions the wafer W supported by the wafer stage WST by driving the wafer stage driving device WSTD based on the measurement result of the laser interferometer 55.

In the present embodiment, the immersion method is applied in order to substantially shorten the exposure wavelength, improve the resolution, and substantially increase the depth of focus. Therefore, at least while the image of the pattern of the grating R is transferred onto the wafer W, the set liquid 50 is filled between the front surface of the wafer W and the distal end surface (lower surface) 7 of the optical element (lens) 60 on the wafer side of the projection optical system PL. As described above, the lens 60 is exposed on the distal end side of the projection optical system PL, and the liquid 50 is brought into contact with only the lens 60. This can prevent corrosion and the like of the metal barrel PK. Further, since the tip end surface 7 of the lens 60 is sufficiently smaller than the barrel PK of the projection optical system PL and the wafer W and the liquid 50 is in contact with only the lens 60 as described above, the liquid 50 is partially filled on the image plane side of the projection optical system PL. That is, the liquid immersion portion between the projection optical system PL and the wafer W is sufficiently smaller than the wafer W. In the present embodiment, pure water is used as the liquid 50. When the exposure light EL is far ultraviolet light (DUV light) such as glow light (g-line, h-line, i-line) in the ultraviolet region emitted from a mercury lamp or KrF excimer laser light (wavelength 248nm), the exposure light EL can be transmitted through pure water not only to ArF excimer laser light.

The exposure apparatus EX includes a liquid supply device 1 that supplies a set liquid 50 to a space 56 between a distal end surface (distal end surface of the lens 60) 7 of the projection optical system PL and the wafer W, and a liquid recovery device 2 that is a 2 nd recovery device that recovers the liquid 50 in the space 56, that is, the liquid 50 on the wafer W. The liquid supply device 1 is used to fill a part of the image plane side of the projection optical system PL with the liquid 50, and includes a tank for storing the liquid 50, a pressure pump, a temperature adjustment device for adjusting the temperature of the liquid 50 supplied to the space 56, and the like. One end of a supply pipe 3 is connected to the liquid supply apparatus 1, and a supply nozzle 4 is connected to the other end of the supply pipe 3. The liquid supply apparatus 1 supplies the liquid 50 to the space 56 through the supply pipe 3 and the supply nozzle 4.

The liquid recovery device 2 includes a suction pump, a container for storing the recovered liquid 50, and the like. One end of a recovery pipe 6 is connected to the liquid recovery device 2, and a recovery nozzle 5 is connected to the other end of the recovery pipe 6. The liquid recovery apparatus 2 recovers the liquid 50 in the space 56 through the recovery nozzle 5 and the recovery pipe 6. When the space 56 is filled with the liquid 50, the controller CONT drives the liquid supply device 1 to supply a set amount of the liquid 50 per unit time to the space 56 through the supply pipe 3 and the supply nozzle 4, and drives the liquid recovery device 2 to recover a set amount of the liquid 50 per unit time from the space 56 through the recovery nozzle 5 and the recovery pipe 6. Thereby, the liquid 50 is disposed in the space 56 between the distal end surface 7 of the projection optical system PL and the wafer W, and an immersion portion is formed. Here, the controller CONT arbitrarily sets the amount of liquid supplied to the space 56 per unit time by controlling the liquid supply device 1, and arbitrarily sets the amount of liquid recovered from the wafer W per unit time by controlling the liquid recovery device 2.

Fig. 2 shows a positional relationship between the circular arc-shaped effective exposure area formed on the wafer and the optical axis in the present embodiment. In the present embodiment, as shown in fig. 2, the aberration correction area AR, which is an area in which aberrations are corrected well, is defined as an arc shape by 2 line segments parallel in the X direction separated by the distance H, the circle of the outer diameter (radius) R0, the circle of the inner diameter (radius) Ri, and the circle of the outer diameter (radius) R0 centered on the optical axis AX. The effective exposure area (effective imaging area) ER is formed in an arc shape by 2 arcs having a radius of curvature R and spaced apart in the X direction and 2 line segments having a length D parallel to the X direction and spaced apart by a distance H, in such a manner as to be substantially inscribed in the arc-shaped aberration correction area AR.

In this way, all the effective imaging regions ER that the projection optical system PL has exist in a region away from the optical axis AX. Further, the dimension along the Y direction of the arc-shaped effective exposure area ER is H, and the dimension along the X direction is D. Therefore, although not shown, the optical axis may not be included in the grating R to form an arc-shaped illumination region (i.e., effective illumination region) having a size and shape optically corresponding to the arc-shaped effective exposure region ER.

Further, in the exposure apparatus of the present embodiment, a configuration is adopted in which the inside of the projection optical system PL is kept in an airtight state between the optical member (the lens L11 in the 1 st and 2 nd embodiments, the lens L1 in the 3 rd and 5 th embodiments, the lens L21 in the 4 th and 6 th embodiments, the lens L51 in the 7 th embodiments) disposed closest to the raster side among the optical members constituting the projection optical system PL and the boundary lens Lb (the lens L217 in the 1 st and 2 nd embodiments, the lens L18 in the 3 rd embodiment, the lens L36 in the 4 th embodiment, the lens L20 in the 5 th embodiment, the lens L41 in the 6 th embodiment, and the lens L70 in the 7 th embodiment), and the inside gas of the projection optical system PL may be replaced with an inert gas such as helium gas and nitrogen or substantially kept in a vacuum state. Further, although the grating R, the grating stage RS, and the like are disposed in the narrow optical path between the illumination optical system IL and the projection optical system PL, an inert gas such as nitrogen or helium is filled or substantially kept in a vacuum state in the interior of a case (not shown) that hermetically encloses the grating R, the grating stage RS, and the like.

Fig. 3 is a schematic view showing a structure between a boundary lens and a wafer in example 1 of the present embodiment. Referring to fig. 3, in embodiment 1, the boundary lens Lb has a convex surface toward the raster side (1 st surface side). In other words, the grating-side surface Sb of the boundary lens Lb has a positive refractive power. Further, the optical path between the boundary lens Lb and the wafer W is filled with a medium Lm having a refractive index larger than 1.1. In example 1, a deionized water action medium Lm was used.

Fig. 4 is a schematic view showing a structure between a boundary lens and a wafer according to example 2 of the present embodiment. Referring to fig. 4, in embodiment 2 as well, the boundary lens Lb has a convex surface toward the grating side, and the grating-side surface Sb has a positive refractive power. However, in embodiment 2, unlike embodiment 1, the parallel plane plate Lp is disposed in the optical path between the boundary lens Lb and the wafer W so as to be freely inserted and removed, and the optical path between the boundary lens Lb and the parallel plane plate Lp and the optical path between the parallel plane plate Lp and the wafer W are filled with a medium Lm having a refractive index larger than 1.1. In example 2, deionized water was used as the medium Lm, as in example 1.

In the present embodiment, when performing exposure by the step-and-scan method in which the projection optical system PL is relatively moved and scanning exposure is performed on the wafer W, the liquid medium Lm is continuously filled in the optical path between the boundary lens Lb of the projection optical system PL and the wafer W from the start to the end of the scanning exposure. Further, as disclosed in japanese patent laying-open No. 10-303114, for example, a configuration may be adopted in which the wafer holder stage WT is configured in a container shape so as to be capable of storing a liquid (medium Lm), and the wafer W is positioned and held by vacuum suction at the center of the inner bottom portion (in the liquid). At this time, the distal end portion of the lens barrel of the projection optical system PL is in the liquid, and the optical surface of the boundary lens Lb on the wafer side is in the liquid.

Thus, an environment in which the exposure light is hardly absorbed is formed over the entire optical path from the light source 100 to the substrate P. As described above, the illumination region on the grating R and the exposure region (i.e., the effective exposure region ER) on the wafer W are arc-shaped extending in the X direction. Therefore, by performing position control of the grating R and the substrate W by the grating stage control device RSTD, the substrate stage drive device, the laser interferometer, and the like, and by moving (scanning) the grating stage RST and the substrate stage WS in the X direction and further synchronously moving (scanning) the grating R and the substrate (wafer) W, the grating pattern is scan-exposed on the substrate W for an exposure area having a width equal to the Y-direction dimension H of the effective exposure area ER and a length corresponding to the scanning amount (movement amount) of the substrate W.

In each of the embodiments, the height of the aspherical surface in the direction perpendicular to the optical axis is defined as y, the distance (amount of decrease) along the optical axis from the tangent plane at the vertex of the aspherical surface to the position on the aspherical surface at the height y is defined as z, the vertex radius of curvature is defined as r, the conic coefficient is defined as k, and the aspherical coefficient of degree n is defined as Cn, and the aspherical surface is expressed by the following equation (a). In each embodiment, a symbol is added to the right side of the surface number to the lens surface forming the aspherical shape.

z＝(y²/r)/[1+{1-(1+k)·)y²/r²]^1/2+c₄·y⁴+c₆·y⁶+c₈·y⁸+c₁₀·y¹⁰+c₁₂·y¹²+c₁₄·y¹⁴+c₁₆·y¹⁶+c₁₈·y¹⁸+c₂₀·y²⁰(a)

In addition, in embodiments 1 and 2, since the values of the aspherical coefficients C16 to C20 are 0, their description is omitted.

In each of the embodiments, the projection optical system PL is configured by a 1 st imaging optical system G1 for forming an intermediate image of a pattern of the grating R arranged on the object surface (1 st surface), and a 2 nd imaging optical system G2 for forming a reduced image of the grating pattern on the wafer W arranged on the image surface (2 nd surface) based on light from the intermediate image. Here, the 1 st imaging optical system G1 is a catadioptric optical system including a 1 st concave mirror CM1 and a 2 nd concave mirror CM2, and the 2 nd imaging optical system G2 is a refractive optical system.

(embodiment 1)

Fig. 5 shows a lens structure of a projection optical system according to embodiment 1 of the present embodiment. Referring to fig. 5, in the projection optical system PL relating to embodiment 1, the 1 st imaging optical system G1 includes, in order from the grating side in the light traveling direction, a lenticular lens L11 having an aspherical convex surface facing the wafer side, a lenticular lens L12, a negative meniscus lens L13 having an aspherical concave surface facing the grating side, and a 1 st concave mirror CM 1. In the 1 st imaging optical system G1, the reflection surface of the 2 nd concave mirror CM2 for reflecting the light, which has been reflected by the 1 st concave mirror CM1 and passed through the negative meniscus lens L13, toward the 2 nd imaging optical system G2 is disposed in a region not including the optical axis AX between the lenticular lens L12 and the negative meniscus lens L13. Therefore, the lenticular lens L11 and the lenticular lens L12 constitute the 1 st lens group having a positive refractive power. The 1 st concave mirror CM1 constitutes a concave mirror disposed in the vicinity of the pupil plane of the 1 st imaging optical system G1.

On the other hand, the 2 nd imaging optical system G2 includes, in order from the grating side in the light traveling direction, a positive meniscus lens L21 having a non-concave surface facing the grating side, a biconvex lens L22, a positive meniscus lens L23 having an aspherical surface facing the wafer side, a negative meniscus lens L24 having an aspherical surface facing the grating side, a negative meniscus lens L25 having a convex surface facing the grating side, a biconcave lens L26 having an aspherical surface facing the grating side, a positive meniscus lens L27 having a concave surface facing the grating side, a negative meniscus lens L28 having an aspherical surface facing the grating side, a biconvex lens L29, a biconvex lens L210, a positive meniscus lens L211 having a convex surface facing the grating side, an aperture stop AS, a positive meniscus lens L212 having a concave surface facing the grating side, a biconvex lens L213, a positive meniscus lens L214 having an aspherical surface facing the wafer side, a convex surface facing the grating side, a positive meniscus lens L215 having a convex surface facing the grating side, a, A positive meniscus lens L216 having an aspherical concave surface facing the wafer side, and a plano-convex lens L217 (boundary lens Lb) having a plane facing the wafer side.

In embodiment 1, all the transmission members (lenses) and all the reflection members (the 1 st concave mirror CM1, the 2 nd concave mirror CM2) having power constituting the projection optical system PL are arranged along a single optical axis AX. That is, of the transmission members constituting the 2 nd imaging optical system G2, 100% of the transmission members are formed of quartz. Further, a medium Lm made of deionized water is filled in the optical path between the plano-convex lens L217 as the boundary lens Lb and the wafer W. In embodiment 1, light from the grating R passes through lenses L11 to L13 and enters the 1 st concave mirror CM 1. The light reflected by the 1 st concave mirror CM1 passes through the lens L13 and the 2 nd concave mirror CM2, and forms an intermediate image of the grating R in the vicinity of the 1 st concave mirror CM 1. The light reflected by the 2 nd concave mirror CM2 passes through the lenses L21 to L217(Lb) to form a reduced image of the grating R on the wafer W.

In embodiment 1, all the transmission members (lenses) constituting the projection optical system PL are made of quartz (SiO)₂) ArF exciplex laser light as exposure light has an oscillation center wavelength of 193.306nm and a refractive index of quartz changed by-1.591 × 10 per +1pm at a wavelength around 193.306nm^-6Is varied and varies +1.591 × 10 at a wavelength of every-1 pm^-6In other words, the dispersion of the refractive index of quartz (dn/d. lamda.) is-1.591 × 10 at about 193.306nm^-6/pm. furthermore, the refractive index of the deionized water varies by-2.6 × 10 per +1pm wavelength around 193.306nm^-6Is varied and varies +2.6 × 10 at a wavelength of every-1 pm^-6The ratio of (a) to (b) is varied. In other words,the refractive index dispersion (dn/d lambda) of the deionized water is-2.6 × 10 at about 193.306nm^-6/pm。

Thus, in example 1, the refractive index of 1.5603261 for quartz with a center wavelength of 193.306nm, 1.560325941 for quartz with a wavelength of 193.306nm +0.1pm of 193.3061nm, and 1.560326259 for quartz with a wavelength of 193.306nm-0.1pm of 193.3059 nm. The refractive index of the deionized water with the central wavelength of 193.306nm is 1.47, the refractive index of the deionized water with the central wavelength of 193.306nm +0.1pm (193.3061 nm) is 1.46999974, and the refractive index of the deionized water with the central wavelength of 193.306nm-0.1pm (193.3059 nm) is 1.47000026.

In the following table (1), specification values regarding the projection optical system PL of embodiment 1 are disclosed. In table (1), λ represents the center wavelength of the exposure light, 13 represents the projection magnification (imaging magnification of the entire system), NA represents the image-side (wafer-side) numerical aperture, Ro and Ri represent the outer radius and inner radius of the aberration correction area AR, H and D represent the Y-direction dimension and X-direction dimension of the effective exposure area ER, R represents the size of the radius of curvature of the circular arc defining the circular arc-shaped effective exposure area ER (effective imaging area), Y represents the size of the radius of curvature of the circular arc defining the circular arc-shaped effective exposure area ER (effective imaging area), and₀representing the maximum image height. The order of surfaces from the grating side in the light traveling direction from the grating surface as the object surface (1 st surface) to the wafer surface as the image surface (2 nd surface) is represented by surface numbers, r represents the radius of curvature of each surface (vertex radius of curvature: mm in the case of an aspherical surface), d represents the on-axis distance of each surface, i.e., the surface distance (mm), and n represents the refractive index for the center wavelength.

The surface interval d changes its sign according to the degree of reflection. Therefore, the sign of the face interval d is negative in the optical path from the 1 st concave mirror CM1 to the 2 nd concave mirror CM2, and positive in the other optical paths. In addition, regardless of the incident direction of light, the radius of curvature of the convex surface facing the grating side is made positive, and the radius of curvature of the concave surface is made negative. The expressions in table (1) are also the same in table (2) below.

[ Table 1]

(Main data)

λ＝193.306nm

β＝+1/4

NA＝1.04

Ro＝17.0mm

Ri＝11.5mm

H＝26.0mm

D＝4.0mm

R＝20.86mm

Y₀＝17.0mm

(optical Components Zhuyuan)

Number of noodle	r	d	n	Optical member
						(Grating surface)	70.25543
1	444.28100	45.45677	1.5603261	(L11)
					2*	-192.24078	1.00000
3	471.20391	35.53423	1.5603261	(L12)
					4	-254.24538	122.19951
5*	-159.65514	13.00000	1.5603261	(L13)
					6	-562.86259	9.00564
7	-206.23868	-9.00564		(CM1)
					8	-562.86259	-13.00000	1.5603261	(L13)
9*	-159.65514	-107.19951
					10	3162.83419	144.20515		(CM2)
11	-389.01215	43.15699	1.5603261	(L21)
					12	-198.92113	1.00000
13	3915.27567	42.01089	1.5603261	(L22)
					14	-432.52137	1.00000
15	203.16777	62.58039	1.5603261	(L23)
					16*	515.92133	18.52516
17*	356.67027	20.00000	1.5603261	(L24)
					18	269.51733	285.26014
19	665.61079	35.16606	1.5603261	(L25)
					20	240.55938	32.43496
21*	-307.83344	15.00000	1.5603261	(L26)
					22	258.17867	58.24284
23	-1143.34122	51.43638	1.5603261	(L27)
					24	-236.25969	6.67292
25*	1067.55487	15.00000	1.5603261	(L28)
					26	504.02619	18.88857
27	4056.97655	54.00381	1.5603261	(L29)
					28	-283.04360	1.00000
29	772.31002	28.96307	1.5603261	(L210)
					30	-8599.87899	1.00000
31	667.92225	52.94747	1.5603261	(L211)
					32	36408.68946	2.30202
33	∞	42.27703		(AS)

34	-2053.34123	30.00000	1.5603261	(L212)
					35	-514.67146	1.00000
36	1530.45141	39.99974	1.5603261	(L213)
					37	-540.23726	1.00000
38	370.56341	36.15464	1.5603261	(L214)
					39*	12719.40982	1.00000
40	118.92655	41.83608	1.5603261	(L215)
					41	190.40194	1.00000
42	151.52892	52.42553	1.5603261	(L216)
					43*	108.67474	1.12668
44	91.54078	35.50067	1.5603261	(L217：Lb)
					45	∞	6.00000	1.47	(Lm)

(Crystal round surface)

(aspherical data)

2 noodles

k＝0

C₄＝-8.63025×10^-9C₆＝2.90424×10^-13

C₈＝5.43348×10^-17C₁₀＝1.65523×10^-21

C₁₂＝8.78237×10^-26C₁₄＝6.53360×10^-30

5 sides and 9 sides (same side)

k＝0

C₄＝7.66590×10^-9C₆＝6.09920×10^-13

C₈＝-6.53660×10^-17C₁₀＝2.44925×10^-20

C₁₂＝-3.14967×10^-24C₁₄＝2.21672×10^-28

16 noodles

k＝0

C₄＝-3.79715×10^-8C₆＝2.19518×10^-12

C₈＝-9.40364×10^-17C₁₀＝3.33573×10^-21

C₁₂＝-7.42012×10^-26C₁₄＝1.05652×10^-30

17 side of

k＝0

C₄＝-6.69596×10^-8C₆＝1.67561×10^-12

C₈＝-6.18763×10^-17C₁₀＝2.65428×10^-21

C₁₂＝-4.09555×10^-26C₁₄＝3.25841×10^-31

21 noodles

k＝0

C₄＝-8.68772×10^-8C₆＝-1.30306×10^-12

C₈＝-2.65902×10^-17C₁₀＝-6.56830×10^-21

C₁₂＝3.66980×10^-25C₁₄＝-5.05595×10^-29

25 noodles

k＝0

C₄＝-1.54049×10^-8C₆＝7.71505×10^-14

C₈＝1.75760×10^-18C₁₀＝1.71383×10^-23

C₁₂＝5.04584×10^-29C₁₄＝2.08622×10^-32

39 noodles

k＝0

C₄＝-3.91974×10^-11C₆＝5.90682×10^-14

C₈＝2.85949×10^-18C₁₀＝-1.01828×10^-22

C₁₂＝2.26543×10^-37C₁₄＝-1.90645×10^-32

43 sides

k＝0

C₄＝8.33324×10^-8C₆＝1.42277×10^-11

C₈＝-1.13452×10^-15C₁₀＝1.18459×10^-18

C₁₂＝-2.83937×10^-22C₁₄＝5.01735×10^-26

(value corresponding to the formula)

F1＝164.15mm

Y₀＝17.0mm

R＝20.86mm

(1)F1/Y₀＝9.66

(2)R/Y₀＝1.227

Fig. 6 shows the transverse aberration of embodiment 1. In the aberration diagrams, the image height is represented by Y, the center wavelength is 193.3060nm by a solid line, 193.306nm +0.1pm (193.3059 nm) by a broken line, and 193.306nm-0.1pm (193.3059 nm) by a single-dot chain line. Note that the same applies to fig. 6 and fig. 8 to be described later. As can be seen from the aberration diagrams in fig. 6, in embodiment 1, although a very large image-side numerical aperture (NA 1.04) and a relatively large effective exposure area ER are ensured, chromatic aberration is corrected well for exposure light having a wavelength width of 193.306nm ± 0.1 pm.

[ example 2]

Fig. 7 shows a lens structure of a projection optical system according to embodiment 2 of the present embodiment. Referring to fig. 7, in the projection optical system PL relating to embodiment 2, the 1 st imaging optical system G1 includes, in order from the grating side in the light traveling direction, a lenticular lens L11 having an aspherical convex surface facing the wafer side, a lenticular lens L12, a negative meniscus lens L13 having an aspherical concave surface facing the grating side, and a 1 st concave mirror CM 1. In the 1 st imaging optical system G1, the reflection surface of the 2 nd concave mirror CM2 for reflecting the light, which has been reflected by the 1 st concave mirror CM1 and passed through the negative meniscus lens L13, toward the 2 nd imaging optical system G2 is disposed in a region not including the optical axis AX between the lenticular lens L12 and the negative meniscus lens L13. Therefore, the lenticular lens L11 and the lenticular lens L12 constitute the 1 st lens group having a positive refractive power. The 1 st concave mirror CM1 constitutes a concave mirror disposed in the vicinity of the pupil plane of the 1 st imaging optical system G1.

On the other hand, the 2 nd imaging optical system G2 includes, in order from the grating side in the light traveling direction, a positive meniscus lens L21 having a concave surface facing the grating side, a biconvex lens L22, a positive meniscus lens L23 having a concave surface facing the wafer side, a negative meniscus lens L24 having a convex surface facing the grating side, a negative meniscus lens L25 having a convex surface facing the grating side, a biconcave lens L26 having a concave surface facing the grating side, a positive meniscus lens L27 having a concave surface facing the grating side, a negative meniscus lens L28 having a convex surface facing the grating side, a biconvex lens L29, a biconvex lens L210, a positive meniscus lens L211 having a convex surface facing the grating side, an aperture stop AS, a positive meniscus lens L212 having a concave surface facing the grating side, a biconvex lens L213, a positive meniscus lens L214 having a concave surface facing the wafer side, a convex surface facing the grating side, a positive meniscus lens L215 having a convex surface facing the grating side, a concave surface, A positive meniscus lens L216 having an aspherical concave surface facing the wafer side, and a plano-convex lens L217 (boundary lens Lb) having a plane facing the wafer side.

In embodiment 2, a parallel plane plate Lp is disposed in the optical path between the plano-convex lens L217 as the boundary lens Lb and the wafer W. The optical path between the boundary lens Lb and the parallel flat plate Lp and the optical path between the parallel flat plate Lp and the wafer W are filled with a medium Lm made of deionized water. Further, in embodiment 2, the transmission member (lens) constituting the projection optical system PL is made of quartz or fluorite (CaF)₂) And (4) forming. Specifically, the lens L13, the lens L216, and the lens L217(Lb) are formed of fluorite, and the other lenses and the parallel plane plate Lp are formed of quartz. That is, of the transmission members constituting the 2 nd imaging optical system G2, about 88% of the transmission members are formed of quartz.

In addition, in embodiment 2, all the transmission members (lenses, parallel plane plates) and all the reflection members (1 st concave mirror CM1, 2 nd concave mirror CM2) having power constituting the projection optical system PL are arranged along a single optical axis AX. Thus, in embodiment 2, light from the grating R passes through the lenses L11 to L13 and enters the 1 st concave mirror CM 1. The light reflected by the 1 st concave mirror CM1 passes through the lens L13 and the 2 nd concave mirror CM2, and forms an intermediate image of the grating R in the vicinity of the 1 st concave mirror CM 1. The light reflected by the 2 nd concave mirror CM2 passes through the lenses L21 to L217(Lb) and the parallel plane plate Lp to form a reduced image of the grating R on the wafer W.

In example 2, the ArF exciplex laser light as the exposure light had an oscillation center wavelength of 193.306nm and a refractive index of quartz changed at a wavelength of-1.591 × 10 per +1pm in the vicinity of 193.306nm^-6Is varied and varies +1.591 × 10 at a wavelength of every-1 pm^-6In other words, the dispersion of the refractive index of quartz (dn/d. lamda.) is-1.591 × 10 at about 193.306nm^-6/pm. and, near 193.306nm, the refractive index of fluorite varies by-0.980 × 10 per +1pm wavelength^-6Is varied and varies +0.980 × 10 at a wavelength of every-1 pm^-6In other words, the dispersion of the refractive index of fluorite (dn/d. lamda.) is-0.980 × 10 at about 193.306nm^-6/pm。

In addition, the refractive index of the deionized water at about 193.306nm varied by-2.6 × 10 per +1pm wavelength^-6Is varied and varies +2.6 × 10 at a wavelength of every-1 pm^-6In other words, the dispersion of the refractive index of deionized water (dn/d. lamda.) was-2.6 × 10 at about 193.306nm^-6And/pm. Thus, in example 2, the refractive index of 1.5603261 for quartz with a center wavelength of 193.306nm, 1.560325941 for quartz with a wavelength of 193.306nm +0.1pm of 193.3061nm, and 1.560326259 for quartz with a wavelength of 193.306nm-0.1pm of 193.3059 nm.

The refractive index of the fluorite with the central wavelength of 193.306nm is 1.5014548, the refractive index of the fluorite with the central wavelength of 193.306nm +0.1pm & gt 193.3061nm is 1.501454702, and the refractive index of the fluorite with the central wavelength of 193.306nm-0.1pm & gt 193.3059nm is 1.501454898. The refractive index of the deionized water with the central wavelength of 193.306nm is 1.47, the refractive index of the deionized water with the central wavelength of 193.306nm +0.1pm (193.3061 nm) is 1.46999974, and the refractive index of the deionized water with the central wavelength of 193.306nm-0.1pm (193.3059 nm) is 1.47000026. In the following table (2), specification values regarding the projection optical system PL of embodiment 2 are disclosed.

[ Table 2]

(Main data)

λ＝193.306nm

β＝+1/4

NA＝1.04

Ro＝17.0mm

Ri＝11.5mm

H＝26.0mm

D＝4.0mm

R＝20.86mm

Y₀＝17.0mm

(optical Components Zhuyuan)

Number of noodle	r	d	n	Optical member
						(Grating surface)	72.14497
1	295.66131	46.03088	1.5603261	(L11)
					2*	-228.07826	1.02581
3	847.63618	40.34103	1.5603261	(L12)
					4	-207.90948	124.65407
5*	-154.57886	13.00000	1.5603261	(L13)

6	-667.19164	9.58580
					7	-209.52775	-9.58580		(CM1)
8	-667.19164	-13.00000	1.5603261	(L13)
					9*	-154.57886	-109.65407
10	2517.52751	147.23986		(CM2)
					11	-357.71318	41.75496	1.5603261	(L21)
12	-196.81705	1.00000
					13	8379.53651	40.00000	1.5603261	(L22)
14	-454.81020	8.23083
					15	206.30063	58.07852	1.5603261	(L23)
16*	367.14898	24.95516
					17*	258.66863	20.00000	1.5603261	(L24)
18	272.27694	274.16477
					19	671.42370	49.62123	1.5603261	(L25)
20	225.79907	35.51978
					21*	-283.63484	15.10751	1.5603261	(L26)
22	261.37852	56.71822
					23	-1947.68869	54.63076	1.5603261	(L27)
24	-227.05849	5.77639
					25*	788.97953	15.54026	1.5603261	(L28)
26	460.12935	18.83954
					27	1925.75038	56.54051	1.5603261	(L29)
28	-295.06884	1.00000
					29	861.21046	52.50515	1.5603261	(L210)
30	-34592.86759	1.00000
					31	614.86639	37.34179	1.5603261	(L211)
32	39181.66426	1.00000
					33	∞	46.27520		(AS)
34	-11881.91854	30.00000	1.5603261	(L212)
					35	-631.95129	1.00000
36	1465.88641	39.89113	1.5603261	(L213)
					37	-542.10144	1.00000
38	336.45791	34.80369	1.5603261	(L214)
					39*	2692.15238	1.00000
40	112.42843	43.53915	1.5603261	(L215)

41	189.75478	1.00000
					42	149.91358	42.41577	1.5603261	(L216)
43*	107.28888	1.06533
					44	90.28791	31.06087	1.5603261	(L217：Lb)
45	∞	1.00000	1.47	(Lm)
					46	∞	3.00000	1.5603261	(Lp)
47	∞	5.00000	1.47	(Lm)

(Crystal round surface)

(aspherical data)

2 noodles

k＝0

C₄＝9.57585×10^-9C₆＝7.09690×10^-13

C₈＝1.30845×10^-16C₁₀＝-5.52152×10^-22

C₁₂＝4.46914×10^-26C₁₄＝-2.07483×10^-29

5 sides and 9 sides (same side)

k＝0

C₄＝1.16631×10^-8C₆＝6.70616×10^-13

C₈＝-1.87976×10^-17C₁₀＝1.71587×10^-20

C₁₂＝-2.34827×10^-24C₁₄＝1.90285×10^-28

16 noodles

k＝0

C₄＝-4.06017×10^-8C₆＝2.22513×10^-12

C₈＝-9.05000×10^-17C₁₀＝3.29839×10^-21

C₁₂＝-7.46596×10^-26C₁₄＝1.06948×10^-30

17 side of

k＝0

C₄＝-6.69592×10^-8C₆＝1.42455×10^-12

C₈＝-5.65516×10^-17C₁₀＝2.48078×10^-21

C₁₂＝-2.91653×10^-26C₁₄＝1.53981×10^-31

21 noodles

k＝0

C₄＝-7.97186×10^-8C₆＝-1.32969×10^-12

C₈＝-1.98377×10^-17C₁₀＝-4.95016×10^-21

C₁₂＝2.53886×10^-25C₁₄＝-4.16817×10^-29

25 noodles

k＝0

C₄＝-1.55844×10^-8C₆＝7.27672×10^-14

C₈＝1.90600×10^-18C₁₀＝1.21465×10^-23

C₁₂＝-7.56829×10^-29C₁₄＝1.86889×10^-32

39 noodles

k＝0

C₄＝-6.91993×10^-11C₆＝7.80595×10^-14

C₈＝3.31216×10^-18C₁₀＝-1.39159×10^-22

C₁₂＝3.69991×10^-27C₁₄＝-4.01347×10^-32

43 sides

k＝0

C₄＝8.30019×10^-8C₆＝1.24781×10^-11

C₈＝-9.26768×10^-16C₁₀＝1.08933×10^-18

C₁₂＝-3.01514×10^-22C₁₄＝5.41882×10^-26

(value corresponding to the formula)

F1＝178.98mm

Y₀＝17.0mm

R＝20.86mm

(1)F1/Y₀＝10.53

(2)R/Y₀＝1.227

Fig. 8 shows the transverse aberration of embodiment 2. As can be seen from the aberration diagrams in fig. 8, in example 2 as well, in the same manner as in example 1, although a very large image-side numerical aperture (NA 1.04) and a relatively large effective exposure area ER are secured, chromatic aberration is favorably corrected for exposure light having a wavelength width of 193.306nm ± 0.1 pm.

Thus, in each example, the ArF excimer laser beam having a wavelength of 193.306nm can ensure a high image-side numerical aperture of 1.04 and can ensure a circular arc-shaped effective exposure area (stationary exposure area) of 26.0mm × 4.0mm, and can scan and expose a circuit pattern with high resolution in a rectangular exposure area of, for example, 26mm × 33 mm.

Next, embodiment 3 of the present invention will be explained. Fig. 9 shows a lens structure of a catadioptric projection optical system according to embodiment 3 of the present invention. The catadioptric projection optical system PL1 according to embodiment 3 is composed of, in order from the object side (i.e., the grating R1 side), a 1 st imaging optical system G1 for forming an intermediate image of the grating R1 located on the 1 st surface, and a 2 nd imaging optical system G2 for forming an intermediate image of the grating R1 on a wafer (not shown) located on the 2 nd surface.

The 1 st imaging optical system G1 includes a lens group (4 th lens group or 1 st lens group) G11 having a positive refractive power, a lens L5 described later, and 2 mirrors M1 and M2. The lens group G11 functions to telecentric the grating R1 side. The 2 nd imaging optical system G2 includes 2 mirrors M3 and M4, a lens group (1 st lens group or 3 rd lens group) G21 having negative refractive power, a lens group (2 nd lens group) G22 having positive refractive power, an aperture stop AS1, and a lens group (3 rd lens group) G23 having positive refractive power, which will be described later. The lens group G21 reduces the difference in the viewing angle of the light beam expanded by the mirror 43 by adjusting the magnification, thereby suppressing the occurrence of aberration. The lens group G22 converges the divergent light flux. The lens group G23 collects the light beam in a form having a large numerical aperture on the wafer side.

Here, the lens group G11 is composed of a parallel plane plate L1, a negative meniscus lens L2 in which a concave surface forming an aspherical surface faces the object side, a double convex lens L3, and a positive meniscus lens L4 in which a concave surface forming an aspherical surface faces the wafer side, in this order, in which light from the object side (raster R1 grid) passes.

The light flux having passed through the positive meniscus lens L4 passes through the negative meniscus lens (negative lens) 15 having the concave surface facing the object side, is reflected by the concave mirror (concave mirror or 1 st mirror) M1 having the concave surface facing the object side, passes through the negative meniscus lens 15 again, and is reflected by the convex mirror (optical path splitting mirror or 2 nd mirror) M2 having the convex surface facing the wafer side. The negative meniscus lens 15 functions to satisfy the petzval condition.

The light beam reflected by the convex mirror M2 forms an intermediate image of the grating R1 at a position a shown in fig. 9, in order to reliably separate the optical paths of the light beam directed toward the grating R1 and the light beam directed toward the wafer. Here, the position a is located on or near a plane having the optical axis AX1 on which the concave mirror M1 is disposed as a normal.

Then, the light flux reflected by the convex mirror M2 enters the concave mirror (1 st field mirror or 3 rd mirror) M3 whose concave surface faces the object side, is bent in a direction toward the optical axis AX1 of the catadioptric projection optical system PL1, and is emitted from the concave mirror 3. The light flux emitted from the concave mirror 3 is rapidly converged, and is reflected by a convex mirror (2 nd field mirror or 4 th mirror) M4 whose convex surface faces the wafer side, and is directly incident on the negative meniscus lens L6 constituting the lens group G21. The convex mirror M4 suppresses the occurrence of aberration by mitigating the difference in light beam caused by the enlarged viewing angle of the screen by the concave mirror M3. The negative meniscus lens L5, the concave mirror M1, the convex mirror M2, the concave mirror M3, and the convex mirror M4 form group 2.

The lens group G21 includes, in order of light beam passage, a negative meniscus lens L6 having a convex surface formed in an aspherical shape directed to the object side, and a biconcave lens L7 having a concave surface formed in an aspherical shape directed to the wafer side. Since the negative meniscus lens L6 and the biconcave lens L7 have aspherical lens surfaces, they can have a large numerical aperture on the image side of the catadioptric projection optical system PL1, and can obtain good imaging performance over the entire exposure region.

The lens group G22 is composed of, in order of light beam passage, a positive meniscus lens L8 having a concave surface forming an aspherical surface facing the object side, a lenticular lens L9, a positive meniscus lens L10 having a concave surface forming an aspherical surface facing the object side, a lenticular lens L11, and a lenticular lens L12. The lens group G23 is composed of, in order of light beam passage, a positive meniscus lens L13 with the convex surface facing the object side, a positive meniscus lens L14 with the convex surface facing the object side, a positive meniscus lens L15 with the convex surface facing the object side, a positive meniscus lens L16 with the concave surface formed in an aspherical shape facing the wafer side, and a plano-convex lens L18 with the convex surface facing the object side and having a positive refractive power. The lens group G22, the aperture stop AS1, and the lens group G23 form the 4 th group.

The catadioptric projection optical system PL1 is configured to satisfy the condition of 0.17 < Ma/L < 0.6, where Ma is the distance on the optical axis AX1 between the mirror M3 and the aperture stop AS1, and L1 is the distance between the grating R1 and the wafer. By satisfying the lower limit of Ma/L, mechanical interference between the concave mirror M3 and the lens groups G21 and G22 can be avoided. Further, by satisfying Ma/L as an upper limit, the entire length of the catadioptric projection optical system PL1 can be prevented from being elongated and becoming large. In order to reliably avoid mechanical interference and reliably avoid extension and size increase of the entire length of the projection optical system, it is preferable to adopt a configuration satisfying the condition of 0.5 < Ma/L < 0.2.

When the catadioptric projection optical system PL1 according to this embodiment is used in an exposure apparatus, pure water having a refractive index of about 1.4 is inserted into the optical path between the lens L18 and the wafer, assuming that the refractive index of the environment in the catadioptric projection optical system PL1 is 1. Therefore, the wavelength of the exposure light in pure water is about 0.71(1/1.4) times, and the resolution can be improved.

Furthermore, the optical axes AX1 of all the optical elements included in the catadioptric projection optical system PL1 and having a set refractive power are arranged substantially on a single straight line, and the region of the image formed on the wafer by the catadioptric projection optical system PL1 is an off-axis region not including the optical axis AX 1. Therefore, in the production of the catadioptric projection optical system PL1, the ease of production can be reduced, and relative adjustment of the optical members can be easily performed.

As with the catadioptric projection optical system PL1 according to embodiment 3, since an intermediate image of the grating R1 is formed in the 1 st imaging optical system G1, even when the numerical aperture of the catadioptric projection optical system PL1 is increased, the optical paths of the light flux directed toward the grating R1 and the light flux directed toward the wafer can be easily and reliably separated. Further, since the lens group G21 having negative refractive power is disposed in the 2 nd imaging optical system G2, the total length of the catadioptric projection optical system PL1 can be shortened, and adjustment for satisfying the petzval condition can be easily performed. The lens group G21 reduces the difference in the viewing angle of the light beam expanded by the concave mirror M3, and suppresses the occurrence of aberration. Therefore, even when the numerical apertures of the catadioptric projection optical system PL1 on the grating R1 side and the wafer side are increased in order to improve resolution, good imaging performance can be obtained over the entire exposure region.

Next, embodiment 4 of the present invention will be described with reference to the drawings. Fig. 10 shows a lens structure of a catadioptric projection optical system according to embodiment 4 of the present invention. The catadioptric projection optical system PL2 according to embodiment 4 is composed of, in order from the object side (i.e., the grating R2 side), a 1 st imaging optical system G3 for forming an intermediate image of the grating R2 located on the 1 st surface, and a 2 nd imaging optical system G4 for forming an intermediate image of the grating R2 on a wafer (not shown) located on the 2 nd surface.

The 1 st imaging optical system G3 includes a lens group (4 th lens group or 1 st lens group) G31 having a positive refractive power, a lens L24 described later, and 2 mirrors M21 and M22. The lens group G31 functions to telecentric the grating R2 side. The 2 nd imaging optical system G4 includes 2 mirrors M23 and M24, a lens group (1 st lens group or 3 rd lens group) G41 having negative refractive power, a lens group (2 nd lens group) G42 having positive refractive power, an aperture stop AS2, and a lens group (3 rd lens group) G43 having positive refractive power, which will be described later. The lens group G41 reduces the difference in the viewing angle of the light beam expanded by the mirror M23 by adjusting the magnification, thereby suppressing the occurrence of aberration. The lens group G42 converges the divergent light flux. The lens group G43 collects the light beam in a form having a large numerical aperture on the wafer side.

Here, the lens group G31 is composed of a parallel plane plate L21, a positive meniscus lens L22 having a concave surface formed in an aspherical shape directed to the object side, and a double convex lens L23 in order of light rays from the object side (grating R2). The light flux having passed through the double convex lens L23 passes through a negative meniscus lens (negative lens) L24 having a concave surface facing the object side, is reflected by a concave mirror (concave mirror or 1 st mirror) M21 having a concave surface forming an aspherical surface facing the object side, passes through the negative meniscus lens L24 again, and is reflected by a convex mirror (beam splitter or 2 nd mirror) M22 having a convex surface forming an aspherical surface facing the wafer side. Here, the negative meniscus lens L24 functions to satisfy the petzval condition.

The light beam reflected by the convex mirror M22 forms an intermediate image of the grating R2 at the position b shown in fig. 10, in order to reliably separate the optical paths of the light beam directed toward the grating R2 and the light beam directed toward the wafer. Here, the position b is located on or near a plane having the optical axis AX2 on which the concave mirror M21 is disposed as a normal.

Then, the light beam reflected by the convex mirror M22 enters the concave mirror (1 st field mirror or 3 rd mirror) M23 having its concave surface directed to the object side, is bent in a direction toward the optical axis AX2 of the catadioptric projection optical system PL2, and is reflected by the concave mirror 23. The light flux emitted from the concave mirror M23 is converged rapidly, and is reflected by a convex mirror (2 nd field mirror or 4 th mirror) M24 that directs a convex surface having an aspherical shape toward the wafer side, and is directly incident on the double concave lens L25 constituting the lens group G41. The convex mirror M24 suppresses the occurrence of aberration by mitigating the difference in light beam caused by the enlarged viewing angle of the screen by the concave mirror M23. The negative meniscus lens L24, the concave mirror M21, the convex mirror M22, the concave mirror M23, and the convex mirror M24 form group 2.

The lens group G41 includes, in order of light beam passage, a biconcave lens L25 in which the concave surface having an aspherical shape faces the object side, and a biconcave lens L26 in which the concave surface having an aspherical shape faces the wafer side. Since the biconcave lens L25 and the biconcave lens L26 have aspheric lens surfaces, they can have a large numerical aperture on the image side of the catadioptric projection optical system PL2, and can achieve good imaging performance over the entire exposure region.

The lens group G42 is composed of, in order of light beam passage, a double convex lens L27 in which the convex surface forming the aspherical surface faces the object side, a negative meniscus lens L28 in which the convex surface forming the aspherical surface faces the object side, a positive meniscus lens L29 in which the concave surface faces the object side, and a negative meniscus lens L30 in which the convex surface forming the aspherical surface faces the wafer side. The lens group G43 is composed of, in order of light beam passage, a positive meniscus lens L31 with the convex surface facing the object side, a positive meniscus lens L32 with the convex surface facing the object side, a positive meniscus lens L33 with the convex surface facing the object side, a positive meniscus lens L34 with the concave surface forming an aspherical surface facing the wafer side, a positive meniscus lens L35 with the concave surface forming an aspherical surface facing the wafer side, and a plano-convex lens L36 with the convex surface facing the object side. The lens group G42, the aperture stop AS2, and the lens group G43 form the 4 th group.

The catadioptric projection optical system PL2 is configured to satisfy the condition of 0.17 < M2a/L2 < 0.6, where M2 is the distance on the optical axis AX2 between the mirror M23 and the aperture stop AS2, and L2 is the distance between the grating R2 and the wafer. By satisfying the lower limit of M2a/L2, mechanical interference between the concave mirror M23 and the lens groups G41 and G42 can be avoided. Furthermore, by satisfying the upper limit of M2a/L2, the entire length of the catadioptric projection optical system PL2 can be prevented from being elongated and enlarged. In order to reliably avoid mechanical interference and reliably avoid extension and size increase of the entire length of the projection optical system, it is preferable to adopt a configuration satisfying the condition of 0.5 < M2a/L2 < 0.2.

When the catadioptric projection optical system PL2 according to this embodiment is used in an exposure apparatus, pure water having a refractive index of about 1.4 is inserted into the optical path between the lens L36 and the wafer, assuming that the refractive index of the environment in the catadioptric projection optical system PL2 is 1. Therefore, the wavelength of the exposure light in pure water is about 0.71(1/1.4) times, and the resolution can be improved.

Furthermore, the optical axes AX2 of all the optical elements included in the catadioptric projection optical system PL2 and having a set refractive power are arranged substantially on a single straight line, and the region of the image formed on the wafer by the catadioptric projection optical system PL2 is an off-axis region not including the optical axis AX 2. Therefore, in the production of the catadioptric projection optical system PL2, the ease of production can be reduced, and relative adjustment of the optical members can be easily performed.

As with the catadioptric projection optical system PL2 according to embodiment 4, since an intermediate image of the grating R2 is formed in the 1 st imaging optical system G3, even when the numerical aperture of the catadioptric projection optical system PL2 is increased, the optical paths of the light flux directed toward the grating R2 and the light flux directed toward the wafer can be easily and reliably separated. Further, since the lens group G41 having negative refractive power is disposed in the 2 nd imaging optical system G4, the total length of the catadioptric projection optical system PL1 can be shortened, and adjustment for satisfying the petzval condition can be easily performed. The lens group G41 reduces the difference in the viewing angle of the light beam expanded by the concave mirror M23, and suppresses the occurrence of aberration. Therefore, even when the numerical apertures of the catadioptric projection optical system PL2 on the grating R2 side and the wafer side are increased in order to improve resolution, good imaging performance can be obtained over the entire exposure region.

In addition, although the catadioptric projection optical system PL1 according to embodiment 3 described above is configured such that light reflected by the convex mirror M4 is incident on the lens group G21, a reciprocating lens may be disposed between the convex mirror M4 and the lens group G21. In this case, the light reflected by the concave mirror M3 passes through the shuttle lens, is reflected by the convex mirror M4, passes through the shuttle lens again, and enters the lens group G21. Similarly, in the catadioptric optical system PL2 relating to embodiment 4, a configuration is adopted in which light reflected by the convex mirror M24 is made incident on the lens group G41, but a reciprocating lens may be disposed between the convex mirror M24 and the lens group G41.

In addition, although pure water is interposed between the wafer and the lens closest to the wafer in the catadioptric projection optical systems PL1 and PL2 according to the above embodiments, if the refractive index of the environment in the catadioptric optical systems PL1 and PL2 is set to 1, another medium having a refractive index larger than 1.1 may be interposed.

Values of the specifications regarding the catadioptric projection optical system PL1 of embodiment 3 are shown. In this specification, as shown in fig. 11, a represents a radius centered on the optical axis AX1 of the catadioptric projection optical system PL1 of a portion where exposure light is blocked by optical elements constituting the catadioptric projection optical system PL1, B represents a radius centered on the optical axis AX1 of the catadioptric projection optical system PL1 of the maximum image degree, H represents a length in the X direction of the effective exposure area, and C represents a length in the Y direction of the effective exposure area, respectively. In this specification, NA represents a numerical aperture, d represents a surface distance, n represents a refractive index, and λ represents a center wavelength. In this specification, M represents the distance on the optical axis AX1 between the mirror M3 and the wafer, not shown, and L represents the distance between the grating R1 and the wafer.

Also, table 3 shows optical member specifications regarding the catadioptric projection optical system PL1 of embodiment 3. In the optical member specification shown in table 3, the order of surfaces in the light traveling direction from the object side is shown by the surface number in the 1 st column, the curvature radius (mm) of each surface is shown in the 2 nd column, the surface interval (mm) which is the on-axis interval of each surface is shown in the 3 rd column, and the glass material of the optical member is shown in the 4 th column.

Table 4 shows aspherical coefficients of a lens and a mirror having an aspherical lens surface used in the catadioptric projection optical system PL1 according to embodiment 3. In the aspherical coefficients of table 4, the aspherical numbers of the 1 st column correspond to the surface numbers of the optical component elements in table 1. The curvature (1/mm) of each aspherical surface is shown in column 2, the aspherical surface coefficients of the conical coefficient k and 12 th order are shown in column 3, the aspherical surface coefficients of 4 th order and 14 th order are shown in column 4, the aspherical surface coefficients of 6 th order and 16 th order are shown in column 5, the aspherical surface coefficients of 8 th order and 18 th order are shown in column 6, and the aspherical surface coefficients of 10 th order and 20 th order are shown in column 7, respectively.

In the 3 rd and 4 th embodiments, the aspherical surface is expressed by the above expression (a).

(embodiment 3)

(Zhuyuan)

Image side NA: 1.20

Exposure area: a is 14mm and B is 18mm

H＝26.0mm C＝4mm

Imaging magnification: 1/4 times of

Center wavelength: 193.306nm

Refractive index of quartz: 1.5603261

Refractive index of fluorite: 1.5014548

Refractive index of liquid 1: 1.43664

Quartz Dispersion (dn/d λ): -1.591E-6/pm

Fluorite dispersion (dn/d λ): -0.980E-6/pm

Liquid 1 dispersion (dn/d λ): 2.6E-6/pm

The correspondence value Ma of the conditional expression is 374.65mm L1400 mm

(Table 3)

(optical Components Zhuyuan)

	Radius of curvature (mm)	Surface interval (mm)	Medium
				1 st plane	∞	50.0000
1：	∞	8.0000	Quartz glass
				2：	∞	33.0000
3：	ASP1	25.0422	Quartz glass
				4：	-163.93521	1.0000
5：	355.31617	60.7391	Quartz glass
				6：	-261.84115	1.0000
7：	277.33354	29.0109	Quartz glass
				8：	ASP2	224.5285
9：	-176.61872	20.0000	Quartz glass
				10：	-515.60710	10.4614
11：	ASP 3	-10.4614	Reflecting mirror
				12：	-515.60710	-20.0000	Quartz glass
13：	-176.61872	-204.5285
				14：	ASP4	518.3706	Reflecting mirror
15：	-517.39842	-241.3807	Reflecting mirror
				16：	-652.07494	171.3807	Reflecting mirror
17：	ASP5	20.0000	Quartz glass
				18：	171.59382	41.4743
19：	-245.94525	20.0000	Quartz glass
				20：	ASP6	95.1415
21：	ASP7	28.3218	Quartz glass
				22：	-273.72261	1.0000
23：	578.31684	49.6079	Quartz glass
				24：	-908.96420	1.0000
25：	ASP8	23.1140	Quartz glass
				26：	-713.30127	1.0000

27：	1494.96847	33.6453	Quartz glass
				28：	-1392.26668	100.2723
29：	1382.10341	24.7691	Quartz glass
				30：	-2944133.03600	5.3079
31：	∞	6.0869	Aperture diaphragm
				32：	596.90080	37.1298	Quartz glass
33：	524859.29548	1.0000
				34：	367.83752	41.0495	Quartz glass
35：	1341.09674	1.0000
				36：	180.61255	61.4605	Quartz glass
37：	464.28786	1.0000
				38：	125.76761	49.2685	Quartz glass
39：	ASP9	1.0000
				40：	89.27467	40.3615	Quartz glass
41：	ASP10	1.1254
				42：	79.35451	37.7011	Quartz glass
43：	∞	1.0000	Pure water
				The 2 nd surface	∞

(Table 4)

(aspherical surface coefficient)

Non-ball Flour mark Code

Curvature

k

c4

c6

c8

c10

c12

c14

c16

c18

c20

ASP1

-0.00714775

0.00000E+00

3.70121E-08

4.46586E-13

1.04583E-17

6.67573E-21

-5.81072E-25

5.12689E-29

0.00000E+00

ASP2

0.00091632

0.00000E+00

2.33442E-08

-7.41117E-13

5.06507E-17

-4.32871E-21

1.56850E-25

-1.33250E-30

0.00000E+00

ASP3

-0.00346903

0.00000E+00

-1.67447E-09

-6.49516E-14

-5.93050E-19

-8.10217E-23

3.21506E-27

-6.92598E-32

0.00000E+00

ASP4

-0.00076630

0.00000E+00

3.06927E-10

4.69465E-14

-6.39759E-19

2.45900E-23

-8.28832E-28

1.58122E-32

0.00000E+00

ASP5

0.00125662

0.00000E+00

1.03544E-08

-1.28243E-12

-3.97225E-17

-8.03173E-21

3.90718E-25

1.64002E-30

0.00000E+00

ASP6

0.00507634

0.00000E+00

1.00543E-08

-3.32807E-12

-1.38706E-17

2.64276E-21

1.41136E-25

-6.70516E-30

0.00000E+00

ASP7

-0.00253727

0.00000E+00

-3.94919E-10

9.50312E-14

-1.02163E-18

-1.22660E-22

3.11154E-27

-4.99394E-31

0.00000E+00

ASP8

-0.00025661

0.00000E+00

-9.13443E-09

-8.61174E-14

4.52406E-19

-2.29061E-23

5.86934E-28

-7.10478E-33

0.00000E+00

ASP9

0.00458263

0.00000E+00

2.66745E-08

-3.15468E-13

7.16318E-17

1.41053E-21

-2.22512E-25

1.68093E-29

0.00000E+00

ASP10

0.01117107

0.00000E+00

2.45701E-07

4.19793E-11

4.83523E-15

2.02242E-18

-1.59072E-22

1.41579E-25

0.00000E+00

Fig. 12 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction of the catadioptric projection optical system PL1 according to the present embodiment. In fig. 12, the image height is represented by Y, the lateral aberration at a wavelength of 193.3063nm is represented by a broken line, the lateral aberration at a wavelength of 193.3060nm is represented by a solid line, and the lateral aberration at a wavelength of 193.3057nm is represented by a single-dot chain line, respectively. As shown in the transverse aberration diagram of fig. 12, the catadioptric projection optical system PL1 of the present embodiment has a large numerical aperture and does not include large-sized optical elements, but can correct aberrations well in the entire exposure region.

Values of the specifications regarding the catadioptric projection optical system PL2 of embodiment 4 are shown. Also, table 5 shows optical member specifications regarding the catadioptric projection optical system PL2 of embodiment 4. Table 6 shows aspherical coefficients of a lens and a mirror having aspherical lens surfaces used in the catadioptric projection optical system PL2 according to embodiment 4. The specification, the optical member specification, and the aspherical surface coefficient will be described with the same reference numerals as those used in the specification of the catadioptric projection optical system PL1 of embodiment 3.

(embodiment 4)

(Zhuyuan)

Image side NA: 1.20

Exposure area: a is 13.5mm and B is 17.5mm

H＝26.0mm C＝4mm

Imaging magnification: 1/5 times of

Center wavelength: 193.306nm

Refractive index of quartz: 1.5603261

Refractive index of fluorite: 1.5014548

Refractive index of liquid 1: 1.43664

Quartz Dispersion (dn/d λ): -1.591E-6/pm

Fluorite dispersion (dn/d λ): -0.980E-6/pm

Liquid 1 dispersion (dn/d λ): 2.6E-6/pm

The correspondence value Ma of the conditional expression is 424.85mm L1400 mm

(Table 5)

(optical Components Zhuyuan)

	Radius of curvature (mm)	Surface interval (mm)	Medium
				1 st plane	∞	74.5841
1：	∞	8.0000	Quartz glass
				2：	∞	33.0000
3：	ASP1	22.9375	Quartz glass
				4：	-238.83712	1.0000
5：	226.68450	59.5357	Quartz glass
				6：	-908.69406	202.7480
7：	-165.20501	20.0000	Quartz glass
				8：	-669.93146	45.4417
9：	ASP2	-45.4417	Reflecting mirror
				10：	-669.93146	-20.0000	Quartz glass
11：	-165.20501	-182.7480
				12：	ASP3	476.5531	Reflecting mirror
13：	-410.99944	-182.7518	Reflecting mirror
				14：	ASP4	164.9642	Reflecting mirror
15：	ASP5	28.4827	Quartz glass
				16：	239.45495	38.2383
17：	-497.63245	20.0000	Quartz glass
				18：	ASP6	89.6638
19：	ASP7	48.7904	Quartz glass
				20：	-290.43245	1.0000
21：	1036.93127	60.0000	Quartz glass

22：	1015.63994	19.7285
				23：	-2533.07822	63.4343	Quartz glass
24：	-278.02969	31.4485
				25：	-1388.36824	40.8485	Quartz glass
26：	ASP8	1.0000
				27：	∞	1.0000	Aperture diaphragm
28：	479.05778	35.6437	Quartz glass
				29：	1637.29836	1.0000
30：	329.32813	44.1312	Quartz glass
				31：	1053.37530	1.0000
32：	200.35146	57.3982	Quartz glass
				33：	515.50441	1.0000
34：	118.38756	60.5521	Quartz glass
				35：	ASP9	1.0000
36：	81.03425	37.8815	Fluorite (Fluorite)
				37：	ASP10	1.0000
38：	81.71932	35.7388	Fluorite (Fluorite)
				39：	∞	1.0000	Pure water
The 2 nd surface	∞

(Table 6)

(aspherical surface coefficient)

Non-ball Flour mark Code

Curvature

k

c4

c6

c8

c10

c12

c14

c16

c18

c20

ASP1

-0.00388454

0.00000E+00

2.22245E-08

1.47956E-13

-1.47977E-17

1.83827E-21

-3.79672E-26

6.22409E-31

0.00000E+00

ASP2

-0.00372368

0.00000E+00

-1.37639E-09

-9.27463E-14

-2.38568E-18

-4.78730E-22

4.14849E-26

-2.22906E-30

0.00000E+00

ASP3

-0.00090790

0.00000E+00

-4.17158E-09

1.53090E-13

-4.47592E-18

4.68099E-22

-2.64998E-26

6.12220E-31

0.00000E+00

ASP4

-0.00254948

0.00000E+00

1.56073E-09

1.95837E-14

1.84638E-18

-8.80727E-23

1.81493E-27

-1.48191E-32

0.00000E+00

ASP5

-0.00102929

0.00000E+00

-3.82817E-11

1.56504E-13

-2.89929E-16

1.68400E-20

-5.96465E-25

1.20191E-29

0.00000E+00

ASP6

0.00541154

0.00000E+00

3.81649E-08

-1.10034E-12

-3.69090E-16

1.33858E-20

6.34523E-25

-3.45549E-29

0.00000E+00

ASP7

0.00102903

0.00000E+00

-3.14004E-08

2.87908E-13

-1.32597E-17

2.20315E-22

-5.49818E-27

-4.97090E-32

0.00000E+00

ASP8

-0.00012579

0.00000E+00

-5.21260E-09

-2.97679E-14

-4.97667E-19

1.15081E-23

-9.40202E-29

5.04787E-34

0.00000E+00

ASP9

0.00403277

0.00000E+00

4.99776E-08

-8.99272E-13

6.60787E-17

4.38434E-22

-4.24581E-26

4.81058E-30

0.00000E+00

ASP10

0.01060914

0.00000E+00

2.60785E-07

4.78050E-11

5.21548E-15

1.26891E-18

1.53552E-22

4.32477E-26

0.00000E+00

Fig. 13 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction of the catadioptric projection optical system PL2 according to the present embodiment. In fig. 13, Y represents the image height, a broken line represents the lateral aberration at a wavelength of 193.3063nm, a solid line represents the lateral aberration at a wavelength of 193.3060nm, and a one-dot chain line represents the lateral aberration at a wavelength of 193.3057nm, respectively. As shown in the lateral aberration diagram of fig. 13, the catadioptric projection optical system PL2 of the present embodiment has a large numerical aperture and does not include large-sized optical elements, but can correct aberrations well in the entire exposure region.

Next, embodiment 5 of the present invention will be described with reference to the drawings. Fig. 14 shows a lens structure of a catadioptric projection optical system according to embodiment 5 of the present invention. The catadioptric projection optical system PL1 according to embodiment 5 is composed of, in order from the object side (i.e., the grating R1 side), a 1 st imaging optical system G1 for forming a 1 st intermediate image and a 2 nd intermediate image of the grating R1 located on the 1 st surface, and a 2 nd imaging optical system G2 for relaying the 2 nd intermediate image of the grating R1 on a wafer (not shown) located on the 2 nd surface.

The 1 st imaging optical system G1 is composed of a lens group (field lens group) G11 having a positive refractive power, and 6 mirrors M1 to M6 described later. The lens group G11 has a function of correcting distortion and the like and forming the grating R1 side telecentric. Further, by the function of the lens group G11, even when the grating R1 is disposed at a desired position in the direction of the optical axis AX1, the size of the image of the grating R1 does not change, and therefore the performance of the catadioptric projection optical system PL1 can be maintained high.

The 2 nd imaging optical system G2 is composed of all transmissive optical elements, and includes a lens group (1 st lens group) G21 having positive refractive power, a lens group (2 nd lens group) G22 having negative refractive power, a lens group (3 rd lens group) G23 having positive refractive power, an aperture stop AS1, and a lens group (4 th lens group) G24 having positive refractive power. Since the 2 nd imaging optical system G2 is composed of all transmissive optical elements, it is possible to increase the numerical aperture on the image side of the catadioptric projection optical system PL1 without a load of optical path separation, and to form a reduced image with a high reduction magnification on the 2 nd surface. The lens groups G21 to G24 function favorably to satisfy the petzval condition. Further, the function of the lens groups G21 to G24 can prevent the total length of the catadioptric projection optical system PL1 from becoming large. Further, the lens groups G21 to G23 can correct various aberrations such as coma.

Here, the lens G11 is composed of a parallel plane plate L1, a positive meniscus lens L2 having an aspherical concave surface facing the object side, a lenticular lens L3, and a lenticular lens L4 in order of light passing from the object side (raster R1 side). The light flux passing through the double convex lens L4 is reflected by a concave mirror M1 having a concave surface forming an aspherical surface facing the object side, a convex mirror M2 having a convex surface forming an aspherical surface facing the wafer side, and a concave mirror M3 having a concave surface facing the object side, to form a 1 st intermediate image. The light flux reflected by the mirror M3 is reflected by a convex mirror M4 having a convex surface directed toward the wafer side, a concave mirror M5 having a concave surface formed in an aspherical shape directed toward the object side, and a concave mirror M6 having a concave surface directed toward the wafer side.

Here, since the light beams are continuously reflected by the mirrors M1 to M6 without passing through the lenses, the petzval condition can be easily satisfied by adjusting the respective mirrors M1 to M6. Further, the regions for holding the mirrors M1 to M6 can be secured, and the mirrors M1 to M6 can be easily held. Further, by changing the curvature radius of each of the mirrors M1 to M6, the field curvature can be easily corrected. Further, the light beam reflected by the mirror M6 forms the 2 nd intermediate image.

In this case, since the concave mirror M3 is disposed at the position farthest from the optical axis AX1 and the light flux can be condensed by the concave mirror M3, the light flux can be largely deviated from the optical axis AX1 of the catadioptric projection optical system PL1 without interposing a lens between the mirrors M1 to M6, and interference of the light flux can be avoided. Further, by continuously reflecting the light flux by the 4 mirrors M3 to M6, the increase in the total length of the catadioptric projection optical system PL1 can be avoided.

The lens group G21 is composed of, in order of light beam passage, a positive meniscus lens L5 with its convex surface facing the object side, a positive meniscus lens L6 with its concave surface forming an aspherical shape facing the wafer side, a positive meniscus lens L7 with its convex surface facing the object side, a negative meniscus lens L8 with its convex surface facing the object side, and a negative meniscus lens L9 with its convex surface forming an aspherical shape facing the object side. The lens group G22 is composed of a biconcave lens L10 in which a concave surface formed in an aspherical shape faces the wafer side. The lens group G23 is composed of, in order of light beam passage, a plano-convex lens L11 with a plane forming an aspherical surface facing the object side, a negative meniscus lens L12 with a convex surface facing the object side, a biconvex lens L13, a positive meniscus lens L14 with a convex surface facing the object side, and a biconvex lens L15.

The lens group G24 is composed of a biconvex lens L16, a positive meniscus lens L17 with the convex surface facing the object side, a positive meniscus lens L18 with the concave surface forming an aspherical surface facing the wafer side, a positive meniscus lens L19 with the concave surface forming an aspherical surface facing the wafer side, and a plano-convex lens L20 with the convex surface facing the object side.

The catadioptric projection optical system PL1 is configured so that the distance between the light beam from the mirror M3 and the aperture stop AS1 from AX1 is M, and the distance between the grating R1 and the wafer is L, and satisfies the condition of 0.2 < Mb/L < 0.7. When Mb/L exceeds the lower limit, it is difficult to arrange and hold the lenses L5 to L15 constituting the lens groups G21 to G23, which are essential for correcting various aberrations, particularly coma, at correct positions. That is, by satisfying the lower limit of Mb/L, mechanical interference between the concave mirror M3 and the lens groups G21 to G23 can be avoided. Furthermore, by satisfying the upper limit of Mb/L, the total length extension and size increase of the catadioptric projection optical system PL1 can be avoided. In order to more accurately arrange and hold the lenses L5 to L15 and reliably avoid an increase in the overall length of the catadioptric projection optical system PL1, it is preferable to adopt a configuration that satisfies the condition of 0.25 < Mb/L < 0.6.

In addition, in the 5 th embodiment, the 1 st intermediate image is formed between the mirror M3 and the mirror M4, but the 1 st intermediate image may be formed on any optical path between the mirror M2 and the mirror M4.

Next, embodiment 6 of the present invention will be described with reference to the drawings. Fig. 15 shows a lens structure of a catadioptric projection optical system according to embodiment 6 of the present invention. The catadioptric projection optical system PL2 according to embodiment 6 is composed of, in order from the object side (i.e., the grating R2 side), a 1 st imaging optical system G3 for forming a 1 st intermediate image and a 2 nd intermediate image of the grating R1 located on the 1 st surface, and a 2 nd imaging optical system G4 for relaying the 2 nd intermediate image of the grating R2 on a wafer (not shown) located on the 2 nd surface.

The 1 st imaging optical system G3 is composed of a lens group (field lens group) G31 having positive refractive power, a lens L25 described later, and 6 mirrors M11 to M16. The lens group G31 has a function of correcting distortion and the like and forming the grating R2 side telecentric. Further, by the function of the lens group G31, even when the grating R2 is disposed at a position shifted from a desired position in the optical axis direction, the size of the image of the grating R2 does not change, and therefore the performance of the catadioptric projection optical system PL2 can be maintained high.

The 2 nd imaging optical system G4 is composed of all transmissive optical elements, and includes a lens group (1 st lens group) G41 having positive refractive power, a lens group (2 nd lens group) G42 having negative refractive power, a lens group (3 rd lens group) G43 having positive refractive power, an aperture stop AS2, and a lens group (4 th lens group) G44 having positive refractive power. Since the 2 nd imaging optical system G4 is composed of all transmissive optical elements, it is possible to increase the numerical aperture on the image side of the catadioptric projection optical system PL2 without a load of optical path separation, and to form a reduced image with a high reduction magnification on the 2 nd surface. The lens groups G41 to G44 function favorably to satisfy the petzval condition. Further, the configuration of the lens groups G41 to G44 can avoid an increase in the overall length of the catadioptric projection optical system PL 2. Further, the lens groups G41 to G43 can correct various aberrations such as coma.

Here, the lens G31 is composed of a parallel plane plate L21, a positive meniscus lens L22 having an aspherical concave surface facing the object side, a lenticular lens L23, and a lenticular lens L24 in order of light passing from the object side (raster R2 side). The light flux having passed through the double convex lens L24 passes through a negative meniscus lens (negative lens) L25 having a concave surface directed to the object side, is reflected by a concave mirror M11 having a concave surface formed into an aspherical shape directed to the object side, and passes through the negative meniscus lens L25 again. The light flux having passed through the negative meniscus lens L25 is reflected by a convex mirror M12 which directs a convex surface having an aspherical shape toward the wafer side, thereby forming a 1 st intermediate image. The light flux reflected by the mirror M12 is reflected by a concave mirror M13 having a concave surface facing the object side, a convex mirror M14 having a convex surface facing the wafer side, a concave mirror M15 having a concave surface formed in an aspherical shape facing the object side, and a concave mirror M16 having a concave surface facing the wafer side. Here, by adjusting the negative meniscus lens L25, the chromatic aberration can be easily corrected, and the petzval condition can be easily satisfied. Further, by changing the curvature radius of each of the mirrors M11 to M16, the field curvature can be easily corrected. Further, the light beam reflected by the mirror M16 forms the 2 nd intermediate image.

In this case, since the concave mirror M13 is disposed at the position farthest from the optical axis AX2 and the light beam can be condensed by the concave mirror M13, the light beam can be largely deviated from the optical axis AX2 of the catadioptric projection optical system PL2 without interposing a lens between the 4 mirrors M13 to M16, and interference of the light beam can be avoided. Further, by continuously reflecting the light flux by the 4 mirrors M13 to M16, the increase in the total length of the catadioptric projection optical system PL2 can be avoided.

The lens group G41 is composed of, in order of light beam passage, a positive meniscus lens L26 with its convex surface facing the object side, a positive meniscus lens L27 with its concave surface formed into an aspherical shape facing the wafer side, a positive meniscus lens L28 with its convex surface facing the object side, a positive meniscus lens L29 with its concave surface formed into an aspherical shape facing the wafer side, and a negative meniscus lens L30 with its convex surface facing the object side.

The lens group G42 is composed of a biconcave lens L31 in which a concave surface formed in an aspherical shape faces the wafer side. The lens group G43 is composed of, in order of light beam passage, a lenticular lens L32 having a concave surface forming an aspherical surface facing the object side, a negative meniscus lens L33 having a convex surface facing the object side, a lenticular lens L34, a lenticular lens L35, and a lenticular lens L36. The lens group G44 is composed of a biconvex lens L37, a positive meniscus lens L38 with the convex surface facing the object side, a positive meniscus lens L39 with the concave surface forming an aspherical surface facing the wafer side, a positive meniscus lens L40 with the concave surface forming an aspherical surface facing the wafer side, and a plano-convex lens L41 with the convex surface facing the object side.

The catadioptric projection optical system PL2 is configured to satisfy the condition of 0.2 < M2b/L2 < 0.7 when the distance between the mirror M13 and the optical axis AX2 of the aperture stop AS2 is M2b and the distance between the grating R2 and the wafer is L2. When M2b/L2 exceeds the lower limit, it is difficult to arrange and hold the lenses L26 to L36 constituting the lens groups G41 to G43, which are indispensable for correcting various aberrations, particularly coma, at correct positions. That is, by satisfying the lower limit of M2b/L2, mechanical interference between the concave mirror M13 and the lens groups G41 to G43 can be avoided. Furthermore, by satisfying the upper limit of M2b/L2, the entire length of the catadioptric projection optical system PL2 can be prevented from being elongated and enlarged. In order to more accurately position and hold the lenses L26 to L36 and to reliably avoid an increase in the total length of the catadioptric projection optical system PL2, it is preferable to adopt a configuration that satisfies the condition of 0.25 < M2b/L2 < 0.6.

In addition, although the 1 st intermediate image is formed between the mirror M12 and the mirror M13 in the 6 th embodiment, the 1 st intermediate image may be formed on any optical path between the mirror M12 and the mirror M14.

Next, embodiment 7 of the present invention will be described with reference to the drawings. Fig. 16 shows a lens structure of a catadioptric projection optical system according to embodiment 7 of the present invention. The catadioptric projection optical system PL3 according to embodiment 7 is composed of, in order from the object side (i.e., the grating R3 side), a 1 st imaging optical system G5 for forming a 1 st intermediate image and a 2 nd intermediate image of the grating R3 located on the 1 st surface, and a 2 nd imaging optical system G6 for relaying the 2 nd intermediate image of the grating R3 on a wafer (not shown) located on the 2 nd surface.

The 1 st imaging optical system G5 is composed of a lens group (field lens group) G51 having a positive refractive power, and 6 mirrors M21 to M26 described later. The lens group G51 has a function of correcting distortion and the like and forming the grating R2 side telecentric. Further, by the function of the lens group G51, even when the grating R3 is disposed at a desired position in the direction of the optical axis AX3, the size of the image of the grating R3 does not change, and therefore the performance of the catadioptric projection optical system PL3 can be maintained high.

The 2 nd imaging optical system G6 is composed of all transmissive optical elements, and includes a lens group (1 st lens group) G61 having positive refractive power, a lens group (2 nd lens group) G62 having negative refractive power, a lens group (3 rd lens group) G63 having positive refractive power, an aperture stop AS3, and a lens group (4 th lens group) G64 having positive refractive power. Since the 2 nd imaging optical system G6 is composed of all transmissive optical elements, it is possible to increase the numerical aperture on the image side of the catadioptric projection optical system PL3 without a load of optical path separation, and to form a reduced image with a high reduction magnification on the wafer positioned on the 2 nd surface. The lens groups G61 to G64 function favorably to satisfy the petzval condition. Further, the configuration of the lens groups G61 to G64 can avoid an increase in the overall length of the catadioptric projection optical system PL 3. Further, the lens groups G61 to G63 can correct various aberrations such as coma.

Here, the lens G51 is composed of a parallel plane plate L51, a positive meniscus lens L52 having an aspherical concave surface facing the object side, a lenticular lens L53, and a lenticular lens L54 in order of light passing from the object side (raster R3 side). The light flux having passed through the lenticular lens L54 is reflected by a concave mirror M21 having a concave surface forming an aspherical surface facing the object side, a convex mirror M22 having a convex surface forming an aspherical surface facing the wafer side, and a concave mirror M23 having a concave surface facing the object side, thereby forming a 1 st intermediate image. The light flux reflected by the mirror M23 is reflected by a convex mirror M24 having a convex surface directed toward the wafer side, a convex mirror M25 having a convex surface formed into an aspherical shape directed toward the object side, and a concave mirror M26 having a concave surface directed toward the wafer side.

Here, since the light beams are continuously reflected by the mirrors M21 to M26 without passing through the lenses, the petzval condition can be easily satisfied by adjusting the respective mirrors M21 to M26. Further, the area for holding the mirrors M21 to M26 can be secured, and the curvature radius of the mirrors M21 to M26 can be changed to easily correct the field curvature. Further, the light beam reflected by the mirror M26 forms the 2 nd intermediate image.

In this case, since the concave mirror M23 is disposed at the position farthest from the optical axis AX3 and the light flux can be condensed by the concave mirror M23, the light flux can be largely deviated from the optical axis AX3 of the catadioptric projection optical system PL3 without interposing a lens between the mirrors M21 to M26, and interference of the light flux can be avoided. Further, by continuously reflecting the light flux by the 4 mirrors M23 to M26, the increase in the total length of the catadioptric projection optical system PL3 can be avoided.

The lens group G61 is composed of, in order of light beam passage, a double convex lens L55, a positive meniscus lens L56 with a concave surface forming an aspherical shape facing the wafer side, a positive meniscus lens L57 with a convex surface facing the object side, a negative meniscus lens L58 with a convex surface facing the object side, and a negative meniscus lens L59 with a convex surface forming an aspherical shape facing the object side. The lens group G62 is composed of a biconcave lens L60 in which a concave surface formed in an aspherical shape faces the wafer side. The lens group G63 is composed of, in order of light beam passage, a lenticular lens L61 having a convex surface forming an aspherical surface facing the object side, a negative meniscus lens L62 having a convex surface facing the object side, a lenticular lens L63, a lenticular lens L64, and a positive meniscus lens L65 having a concave surface facing the object side.

The lens group G64 is composed of, in order of light beam passage, a biconvex lens L66, a positive meniscus lens L67 with the convex surface facing the object side, a positive meniscus lens L68 with the concave surface forming an aspherical surface facing the wafer side, a positive meniscus lens L69 with the concave surface forming an aspherical surface facing the wafer side, and a plano-convex lens L70 with the convex surface facing the object side.

The catadioptric projection optical system PL3 is configured to satisfy the condition of 0.2 < M3/L3 < 0.7, where M3 is the distance between the mirror M23 and the optical axis AX3 of the aperture stop AS3, and L3 is the distance between the grating R3 and the wafer. When M3/L3 exceeds the lower limit, it is difficult to arrange and hold the lenses L55 to L65 constituting the lens groups G61 to G63, which are essential for correcting various aberrations, particularly coma, at correct positions. That is, by satisfying the lower limit of M3/L3, mechanical interference between the concave mirror M23 and the lens groups G61 to G63 can be avoided. Furthermore, when M3/L3 satisfies the upper limit, it is preferable to adopt a configuration that satisfies the condition of 0.25 < M3/L3 < 0.6 in order to prevent the entire length of the catadioptric projection optical system PL3 from being extended and enlarged and to reliably prevent the entire length of the catadioptric projection optical system PL3 from being enlarged in order to dispose and hold the respective lenses L55 to L70 at more accurate positions.

In addition, in the 7 th embodiment, the 1 st intermediate image is formed between the mirror M23 and the mirror M24, but the 1 st intermediate image may be formed on any optical path between the mirror M22 and the mirror M24.

When the catadioptric projection optical systems PL1 to PL3 according to embodiments 5 to 7 are used in an exposure apparatus, pure water (deionized water) having a refractive index of about 1.4 is introduced into the optical paths between the planoconvex lenses L20, L41, and L70 and the wafer, if the refractive index of the environment in the catadioptric projection optical systems PL1 to PL3 is 1. Therefore, the wavelength of the exposure light in pure water is about 0.71(1/1.4) times, and the resolution can be improved.

The optical axes AX1 to AX3 of all the optical elements included in the catadioptric projection optical systems PL1 to PL3 and having a predetermined refractive power are substantially arranged on a single straight line, and the regions of the images formed on the wafer by the catadioptric projection optical systems PL1 to PL3 are off-axis regions not including the optical axes AX1 to AX 3. Therefore, in the manufacture of the catadioptric projection optical systems PL1 to PL3, the ease of manufacture can be reduced, and relative adjustment of the optical members can be easily performed.

As in the catadioptric projection optical systems PL1 to PL3 according to embodiments 5 to 7, since 6 mirrors M1 to M6, M11 to M16, and M21 to M26 are included, even when the numerical apertures on the grating R1 to R3 side and the wafer side of the catadioptric projection optical systems PL1 to PL3 are increased in order to improve resolution, the optical paths of the light flux toward the grating R1 to R3 side and the light flux toward the wafer side can be easily and reliably separated without increasing the total length of the catadioptric projection optical systems PL1 to PL 3.

Further, as with the catadioptric projection optical systems PL1 to PL3 according to embodiments 5 to 7, since the 1 st intermediate image and the 2 nd intermediate image are formed by 3-order image forming optical systems, the 1 st intermediate image forms an inverted image of the gratings R1 to R3, the 2 nd intermediate image forms an erect image of the gratings R1 to R3, and the image formed on the wafer is an inverted image. Therefore, when the catadioptric projection optical systems PL1 to PL3 are mounted on the exposure apparatus and scanning exposure is performed on the gratings R1 to R3 and the wafer, the scanning direction of the gratings R1 to R3 and the scanning direction of the wafer are opposite to each other, and thus adjustment can be easily performed with little change in the center of gravity of the entire exposure apparatus. Further, it is possible to reduce the vibration of the catadioptric projection optical systems PL1 to PL3 caused by the change in the center of gravity of the entire exposure apparatus, and to obtain excellent image forming performance over the entire exposure region.

In addition, although pure water (deionized water) is interposed between the wafer and the lens closest to the wafer in the catadioptric projection optical systems PL1 to PL3 according to the above embodiments, another medium having a refractive index larger than 1.1 may be interposed when the refractive index of the environment in the catadioptric projection optical systems PL1 to PL3 is set to 1.

Next, values of the specifications regarding the catadioptric projection optical system PL1 of embodiment 5 shown in fig. 14 are shown. In this specification, as shown in fig. 11 described above, a represents a radius centered on the optical axis AX1 of the catadioptric projection optical system PL1 of the portion where the exposure light is blocked by the optical elements constituting the catadioptric projection optical system PL1, B represents a radius centered on the optical axis AX1 of the catadioptric projection optical system PL1 of the maximum image quality, H represents a length in the X direction of the effective exposure area, and C represents a length in the Y direction of the effective exposure area, respectively. In this specification, NA represents a numerical aperture, d represents a surface distance, n represents a refractive index, and λ represents a center wavelength. In this specification, M represents the distance on the optical axis AX1 between the mirror M3 and the wafer, not shown, and L represents the distance between the grating R1 and the wafer.

Also, table 7 shows optical member specifications regarding the catadioptric projection optical system PL1 of embodiment 5. In the optical member specification shown in table 7, the order of surfaces in the light traveling direction from the object side is shown by the surface number in the 1 st column, the curvature radius (mm) of each surface is shown in the 2 nd column, the surface interval (mm) which is the on-axis interval of each surface is shown in the 3 rd column, and the glass material of the optical member is shown in the 4 th column.

Table 8 shows aspherical coefficients of a lens and a mirror having aspherical lens surfaces used in the catadioptric projection optical system PL1 according to example 5. In the aspherical coefficients of table 8, the aspherical numbers of the 1 st column correspond to the surface numbers of the optical component elements in table 1. The curvature (1/mm) of each aspherical surface is shown in column 2, the aspherical surface coefficients of the conical coefficient k and 12 th order are shown in column 3, the aspherical surface coefficients of 4 th order and 14 th order are shown in column 4, the aspherical surface coefficients of 6 th order and 16 th order are shown in column 5, the aspherical surface coefficients of 8 th order and 18 th order are shown in column 6, and the aspherical surface coefficients of 10 th order and 20 th order are shown in column 7, respectively.

In examples 5 to 7, the aspherical surface is expressed by the above expression (a).

(embodiment 5)

(Zhuyuan)

Image side NA: 1.20

Exposure area: a is 14mm and B is 18mm

H＝26.0mm C＝4mm

Imaging magnification: 1/4 times of

Center wavelength: 193.306nm

Refractive index of quartz: 1.5603261

Refractive index of fluorite: 1.5014548

Refractive index of liquid 1: 1.43664

Quartz Dispersion (dn/d λ): 1.591 × 10^-6/pm

Fluorite Dispersion (dn/d lambda) — 0.980 × 10^-6/pm

Pure water (deionization) dispersion (dn/d lambda) < 2.6 × 10 >^-6/pm

The correspondence value Ma of the conditional expression is 524.49mm L1400 mm

(Table 7)

(optical Components Zhuyuan)

	Radius of curvature (mm)	Surface interval (mm)	Medium
				1 st plane	∞	45.0000
1：	∞	8.0000	Quartz glass

2：	∞	9.4878
				3：	ASP1	25.3802	Quartz glass
4：	-244.04741	1.9583
				5：	2654.01531	49.2092	Quartz glass
6：	-159.85154	1.1545
				7：	294.54453	34.3095	Quartz glass
8：	-572.08259	156.2051
				9：	ASP2	-136.2051	Reflecting mirror
10：	ASP3	412.6346	Reflecting mirror
				11：	-418.20026	-205.0204	Reflecting mirror
12：	-604.04130	160.2153	Reflecting mirror
				13：	ASP4	-211.6245	Reflecting mirror
14：	320.60531	226.6245	Reflecting mirror
				15：	224.13260	25.2194	Quartz glass
16：	346.75878	1.0000
				17：	215.47954	34.3600	Quartz glass
18：	ASP5	1.0000
				19：	266.87857	19.9995	Quartz glass
20：	329.19442	1.0000
				21：	196.43240	20.0000	Quartz glass
22：	115.87410	6.4756
				23：	ASP6	39.3045	Quartz glass
24：	99.87482	55.9109
				25：	-412.64757	24.7282	Quartz glass
26：	ASP7	94.8545
				27：	ASP8	57.3966	Quartz glass
28：	-227.16104	1.0000
				29：	504.83819	20.0000	Quartz glass
30：	407.86902	12.3535
				31：	595.98854	43.0398	Quartz glass
32：	-2001.40538	1.0000
				33：	711.19871	32.6046	Quartz glass
34：	8598.79354	32.0466
				35：	36209.93141	30.0000	Quartz glass
36：	-1731.78793	1.0000

37：	∞	12.6069	Aperture diaphragm
				38：	503.84491	53.3626	Quartz glass
39：	-1088.61181	1.0000
				40：	192.53858	61.7603	Quartz glass
41：	521.19424	1.0000
				42：	122.79200	59.8433	Quartz glass
43：	ASP9	1.0000
				44：	79.97315	39.6326	Fluorite (Fluorite)
45：	ASP10	1.0000
				46：	84.68828	36.1715	Fluorite (Fluorite)
47：	∞	1.0000	Pure water
				The 2 nd surface	∞	0.0000

(Table 8)

(aspherical surface coefficient)

Non-ball Flour mark Code

Curvature

k

c4

c6

c8

c10

c12

c14

c16

c18

c20

ASP1

-0.00059023

0.00000E+00

-2.87641E-08

-1.70437E-11

2.46285E-15

-2.74317E-19

2.07022E-23

-7.79530E-28

0.00000E+00

ASP2

-0.00205780

0.00000E+00

22.50612E-09

2.95240E-14

4.37607E-18

-5.55238E-22

3.88749E-26

-1.13016E-30

0.00000E+00

ASP3

-0.00058562

0.00000E+00

-6.92554E-09

1.39659E-13

-1.09871E-18

3.37519E-23

-1.45573E-27

2.27951E-30

0.00000E+00

ASP4

-0.00123249

0.00000E+00

1.93713E-09

1.07185E-12

-3.34552E-16

3.54315E-20

-5.95219E-24

3.41899E-28

0.00000E+00

ASP5

0.00020189

0.00000E+00

1.37544E-07

-1.06394E-11

7.70843E-17

4.90298E-20

-3.23126E-24

6.76814E-29

0.00000E+00

ASP6

0.00588235

0.00000E+00

2.41559E-07

-1.03766E-11

-6.75114E-17

1.11214E-19

-9.45408E-24

3.57981E-28

0.00000E+00

ASP7

0.00664255

0.00000E+00

2.62150E-08

-9.25408E-12

-1.77845E-16

5.60675E-20

-2.81549E-24

6.89450E-30

0.00000E+00

ASP8

0.00000000

0.00000E+00

-1.26430E-08

1.64939E-13

-6.24373E-18

2.07576E-22

-5.07100E

1.49848E-31

0.00000E+00

ASP9

0.00345726

0.00000E+00

5.92282E-08

-1.56640E-12

1.38582E-16

-4.07966E-21

1.49819E-25

1.10869E-30

0.00000E+00

ASP10

0.01038095

0.00000E+00

2.42802E-07

4.29662E-11

1.62230E-15

6.50272E-19

3.23667E-22

-9.21777E-26

0.00000E+00

Fig. 17 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction of the catadioptric projection optical system PL1 according to the present embodiment. In fig. 17, Y represents the image height, a broken line represents the lateral aberration at a wavelength of 193.3063nm, a solid line represents the lateral aberration at a wavelength of 193.3060nm, and a one-dot chain line represents the lateral aberration at a wavelength of 193.3057nm, respectively. As shown in the lateral aberration diagram of fig. 17, the catadioptric projection optical system PL1 of the present embodiment has a large numerical aperture and does not include large-sized optical elements, but can correct aberrations well in the entire exposure region.

Next, elements relating to a catadioptric projection optical system PL2 of embodiment 6 shown in fig. 15 are shown. Further, fig. 9 shows optical member elements of a catadioptric projection optical system PL2 relating to embodiment 6. Table 10 shows aspherical coefficients of a lens and a mirror having aspherical lens surfaces used in the catadioptric projection optical system PL2 according to embodiment 6. The specification, the optical member specification, and the aspherical surface coefficient will be described with the same reference numerals as those used in the description of the catadioptric optical system PL1 of embodiment 5.

(embodiment 6)

(Zhuyuan)

Image side NA: 1.20

Exposure area: a is 13mm and B is 17mm

H＝26.0mm C＝4mm

Imaging magnification: 1/4 times of

Center wavelength: 193.306nm

Refractive index of quartz: 1.5603261

Refractive index of fluorite: 1.5014548

Refractive index of liquid 1: 1.43664

Quartz Dispersion (dn/d λ): 1.591 × 10^-6/pm

Fluorite Dispersion (dn/d lambda) — 0.980 × 10^-6/pm

Pure water (deionization) dispersion (dn/d lambda) < 2.6 × 10 >^-6/pm

The corresponding value Mb of the conditional expression is 482.14mm L is 1400mm

(watch 9)

(optical Components Zhuyuan)

	Radius of curvature (mm)	Surface interval (mm)	Name of glass Material
				1 st plane	∞	50.9535
1：	∞	8.0000	Quartz glass
				2：	∞	12.7478
3：	ASP1	32.5506	Quartz glass
				4：	-184.43053	1.0000
5：	532.87681	45.9762	Quartz glass
				6：	-271.53626	1.3173
7：	374.46315	38.0103	Quartz glass
				8：	-361.42951	147.1771
9：	-389.08052	20.0000	Quartz glass
				10：	-594.49774	5.5356
11：	ASP2	-5.5356	Reflecting mirror
				12：	-594.49774	-20.00000	Quartz glass
13：	-389.08052	-127.0301
				14：	ASP3	430.8932	Reflecting mirror
15：	-450.43913	-215.6393	Reflecting mirror
				16：	-704.67689	163.6952	Reflecting mirror
17：	ASP4	-206.3833	Reflecting mirror
				18：	317.07489	228.3275	Reflecting mirror
19：	248.60032	30.8186	Quartz glass
				20：	964.03405	1.0000
21：	170.07823	20.0000	Quartz glass
				22：	ASP5	1.0778
23：	174.13726	29.8902	Quartz glass
				24：	294.93424	1.0798
25：	160.77849	33.1276	Quartz glass
				26：	ASP6	9.4275
27：	1185.57325	20.0000	Quartz glass
				28：	103.90360	46.9708

29：	-676.67026	24.5184	Quartz glass
				30：	ASP7	83.5410
31：	ASP8	47.4275	Quartz glass
				32：	-317.19307	1.0000
33：	688.27957	20.0000	Quartz glass
				34：	513.64357	11.2866
35：	883.25368	40.1774	Quartz glass
				36：	-959.41738	1.0000
37：	1222.93397	34.5841	Quartz glass
				38：	-1403.11949	16.9031
39：	2169.40706	37.3055	Quartz glass
				40：	-889.78387	1.0000
41：	∞	9.8461	Aperture diaphragm
				42：	458.32781	52.3568	Quartz glass
43：	-1741.66958	1.0000
				44：	215.86566	59.3939	Quartz glass
45：	659.70674	1.0000
				46：	134.64784	58.8510	Quartz glass
47：	ASP9	1.0004
				48：	96.99608	49.9011	Quartz glass
49：	ASP10	1.0194
				50：	80.22245	40.8996	Quartz glass
51：	∞	1.0000	Pure water
				The 2 nd surface	∞

(watch 10)

(aspherical surface coefficient)

Non-ball Flour mark Code

Curvature

k

c4

c6

c8

c10

c12

c14

c16

c18

c20

ASP1

-0.00057910

0.00000E+00

-9.03366E-08

3.28394E-12

-4.06402E-16

2.52900E-20

-9.19294E-25

2.02082E-30

0.00000E+00

ASP2

-0.00243076

0.00000E+00

3.35976E-09

2.88286E-14

8.73468E-18

-7.00411E-22

4.21327E-26

-9.88714E-31

0.00000E+00

ASP3

-0.00032257

0.00000E+00

-6.53400E-09

1.15036E-13

-9.61655E-19

8.51651E-23

-3.17817E-27

4.60017E-32

0.00000E+00

ASP4

-0.00058501

0.00000E+00

2.54270E-09

6.81523E-13

-1.08474E-16

6.27615E-21

-7.45415E-25

6.45741E-29

0.00000E+00

ASP5

0.00574270

0.00000E+00

2.69000E-08

-1.93073E-12

-2.23058E-16

2.03519E-20

-2.27002E-24

8.48621E-29

0.00000E+00

ASP6

0.00281530

0.00000E+00

-7.99356E-08

1.14147E-11

-4.87397E-16

6.76022E-20

-3.55808E-24

1.84260E-28

0.00000E+00

ASP7

0.00867798

0.00000E+00

-1.01256E-08

-5.60515E-12

-6.85243E-17

2.18957E-20

-1.24639E-24

-1.61382E-29

0.00000E+00

ASP8

0.00000970

0.00000E+00

-1.68383E-08

1.90215E-13

-8.11478E-18

3.37339E-22

-1.15048E-26

5.21646E-31

0.00000E+00

ASP9

0.00313892

0.00000E+00

4.21089E-08

-8.07510E-13

5.31944E-17

-4.15094E-22

-5.28946E-27

1.60653E-30

0.00000E+00

ASP10

0.00959788

0.00000E+00

2.16924E-07

3.52791E-11

1.11831E-15

1.12987E-18

-4.81835E-23

1.62262E-26

0.00000E+00

Fig. 18 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction of the catadioptric projection optical system PL2 according to the present embodiment. In fig. 18, the image height is represented by Y, the lateral aberration at a wavelength of 193.3063nm is represented by a broken line, the lateral aberration at a wavelength of 193.3060nm is represented by a solid line, and the lateral aberration at a wavelength of 193.3057nm is represented by a single-dot chain line, respectively. As shown in the lateral aberration diagram of fig. 18, the catadioptric projection optical system PL2 of the present embodiment has a large numerical aperture and does not include large-sized optical elements, but can correct aberrations well in the entire exposure region.

Next, elements relating to a catadioptric projection optical system PL3 of embodiment 7 shown in fig. 16 are shown. Further, fig. 11 shows optical member elements of a catadioptric projection optical system PL3 relating to embodiment 7. Table 12 shows aspherical coefficients of a lens and a mirror having aspherical lens surfaces used in the catadioptric projection optical system PL3 according to embodiment 7. The specification, the optical member specification, and the aspherical surface coefficient will be described with the same reference numerals as those used in the description of the catadioptric optical system PL1 of embodiment 5.

(7 th embodiment)

(Zhuyuan)

Image side NA: 1.20

Exposure area: a is 13mm and B is 17mm

H＝26.0mm C＝4mm

Imaging magnification: 1/5 times of

Center wavelength: 193.306nm

Refractive index of quartz: 1.5603261

Refractive index of fluorite: 1.5014548

Refractive index of liquid 1: 1.43664

Quartz Dispersion (dn/d λ): 1.591 × 10^-6/pm

Fluorite Dispersion (dn/d lambda) — 0.980 × 10^-6/pm

Pure water (deionization) dispersion (dn/d lambda) < 2.6 × 10 >^-6/pm

The corresponding value Mb of the conditional expression is 508.86mm L is 1400mm

(watch 11)

(optical Components Zhuyuan)

	Radius of curvature (mm)	Surface interval (mm)	Name of glass Material
				1 st plane	∞	63.0159
1：	∞	8.0000	Quartz glass
				2：	∞	11.6805
3：	ASP1	30.7011	Quartz glass
				4：	-244.82575	1.0000
5：	520.7235	50.6283	Quartz glass
				6：	-283.00136	1.0000
7：	455.76131	37.0794	Quartz glass
				8：	-509.23840	143.7025
9：	ASP2	-123.7025	Reflecting mirror
				10：	ASP3	394.2980	Reflecting mirror
11：	-398.57468	-201.7192	Reflecting mirror
				12：	-485.11237	157.8027	Reflecting mirror
13：	ASP4	-206.6789	Reflecting mirror
				14：	329.37813	221.6789	Reflecting mirror
15：	411.95851	28.1592	Quartz glass

16：	-3890.38387	1.1778
				17：	141.65647	33.4870	Quartz glass
18：	ASP5	1.0000
				19：	216.09570	28.6534	Quartz glass
20：	461.77835	1.0000
				21：	202.12479	20.2182	Quartz glass
22：	117.79321	2.6054
				23：	ASP6	20.0000	Quartz glass
24：	98.31887	51.9992
				25：	-251.39135	35.2622	Quartz glass
26：	ASP7	89.1855
				27：	ASP8	42.0591	Quartz glass
28：	-303.33648	2.1164
				29：	606.18864	28.5148	Quartz glass
30：	488.85229	11.9006
				31：	811.09260	45.2273	Quartz glass
32：	-813.38538	1.0000
				33：	1012.41934	42.1336	Quartz glass
34：	-973.64830	21.5611
				35：	-32382.97410	29.5159	Quartz glass
36：	-1075.05682	1.0000
				37：	∞	6.3302	Aperture diaphragm
38：	371.59007	56.0505	Quartz glass
				39：	-4689.87645	9.3746
40：	204.82419	53.7618	Quartz glass
				41：	494.59116	1.0000
42：	125.95227	57.4813	Quartz glass
				43：	ASP9	1.0101
44：	92.58526	43.4772	Quartz glass
				45：	ASP10	1.0360
46：	85.28679	42.2466	Quartz glass
				47：	∞	1.0000	Pure water
The 2 nd surface	∞

(watch 12)

(aspherical surface coefficient)

Aspheric surface number Code

Curvature

k

c4

c6

c8

c10

c12

c14

c16

c18

c20

ASP1

-0.0004476

0.00000E+00

-6.28600E-08

2.01003E-12

-1.86171E-16

4.72866E-21

4.25382E-26

-8.36739E-30

0.00000E+00

ASP2

-0.0019308

0.00000E+00

5.30847E-09

2.39879E-13

1.88016E-18

-1.08670E-22

1.55922E-27

-1.05341E-32

0.00000E+00

ASP3

0.0000635

0.00000E+00

-1.46917E-08

2.39879E-13

1.88016E-18

-1.08670E-22

1.55922E-27

-1.05341E-32

0.00000E+00

ASP4

-0.0009742

0.00000E+00

2.25661E-09

8.15504E-13

-1.75777E-16

1.64720E-20

-2.44697E-24

2.57932E-28

0.00000E+00

ASP5

0.0045455

0.00000E+00

7.76937E-08

-8.42991E-12

3.25677E-16

8.77802E-23

-2.71916E-25

-2.25230E-30

0.00000E+00

0.0078125

0.00281530

0.00000E+00

1.83201E-07

-2.17156E-11

1.87637E-15

-2.53394E-19

1.70711E-23

-1.55669E-27

0.00000E+00

ASP7

0.0063919

0.00000E+00

3.50299E-09

-5.60629E-12

-2.85922E-18

2.57458E-20

-2.26908E-24

3.14291E-29

0.00000E+00

ASP8

0.0001516

0.00000E+00

-1.73728E-08

2.07225E-13

-7.88040E-18

2.99860E-22

-9.28797E-27

3.18623E-31

0.00000E+00

ASP9

0.0037449

0.00000E+00

4.54024E-08

-8.98172E-13

6.42893E-17

5.94025E-22

-6.11068E-26

4.37709E-30

0.00000E+00

ASP10

0.0093466

0.00000E+00

2.17665E-07

2.75156E-11

1.89892E-15

3.45960E-19

7.23960E-23

-1.19099E-26

0.00000E+00

Fig. 19 is a transverse aberration diagram showing transverse aberrations in the meridian direction and the radial direction of the catadioptric projection optical system PL3 according to the present embodiment. In fig. 19, Y represents the image height, a broken line represents the lateral aberration at a wavelength of 193.3063nm, a solid line represents the lateral aberration at a wavelength of 193.3060nm, and a one-dot chain line represents the lateral aberration at a wavelength of 193.3057nm, respectively. As shown in the lateral aberration diagram of fig. 19, the catadioptric projection optical system PL3 of the present embodiment has a large numerical aperture and does not include large-sized optical elements, but can correct aberrations well in the entire exposure region.

The projection optical systems according to the embodiments described above can be applied to the projection exposure apparatus shown in fig. 1. As shown in fig. 1, pure water having a refractive index of about 1.4 with respect to the exposure light is interposed between the projection optical system PL and the wafer W, so that the effective numerical aperture on the wafer W side can be increased to 1.0 or more, and the resolution can be improved. Further, since the projection exposure apparatus shown in fig. 1 includes the projection optical system PL configured by the catadioptric projection optical system according to each of the embodiments described above, even when the numerical apertures on the reticle side and the wafer side are increased, the optical paths of the beam directed to the reticle side and the beam directed to the wafer side can be easily and reliably separated in the projection optical system PL. Therefore, good image forming performance can be obtained over the entire exposure region, and a fine pattern can be exposed satisfactorily.

In the projection exposure apparatus shown in fig. 1, pure water is supplied as a liquid for immersion exposure because ArF excimer laser light is used as exposure light. Pure water has an advantage that it can be easily obtained in a large amount in a semiconductor manufacturing factory or the like and has no adverse effect on a photoresist on a substrate (wafer) W and an optical element (lens) or the like. Further, since pure water has no adverse effect on the environment and the content of impurities is extremely low, an effect of cleaning the surface of the wafer W and the surface of the optical element provided on the distal end surface of the projection optical system PL can be expected.

The refractive index n of pure water (water) for exposure light having a wavelength of about 193nm is approximately 1.44. When ArF exciplex laser light (wavelength 193nm) is used as a light source of exposure light, the wavelength of the light is reduced to 1/n, that is, about 134nm on the substrate, and high resolution is obtained. The depth of focus is expanded by about n times, i.e., about 1.44 times, as compared with the depth of focus in air.

Further, as the liquid, another medium having a refractive index larger than 1.1 with respect to the exposure light may be used. In this case, as the liquid, a liquid that has transmittance to the exposure light and has a refractive index as high as possible and that is stable against the projection optical system PL and the resist applied on the surface of the wafer W can be used.

In the case of using F2 laser light as the exposure light, a liquid that can transmit F2 laser light and is a fluorine-based liquid such as a fluorine-based oil or a perfluorinated polyether (PFPE) can be used as the liquid.

The present invention is also applicable to a double stage type exposure apparatus having 2 stages for placing substrates to be processed such as wafers on the respective stages and independently moving the substrates in the XY direction, as disclosed in japanese patent laid-open No. 10-163099, japanese patent laid-open No. 10-214783, and japanese patent laid-open No. 2000-505958.

In addition, in the case of using the immersion method as described above, the Numerical Aperture (NA) of the projection optical system PL may be 0.9 to 1.3. When the Numerical Aperture (NA) of the projection optical system PL is increased as described above, the image forming performance of the random polarized light conventionally used as the exposure light may be deteriorated due to the polarization effect, and therefore, it is preferable to use polarized illumination. In this case, linear polarization illumination in the longitudinal direction of the line of the grating (mask) R and the line pattern of the space pattern can be performed, and the diffracted light of the S-polarization component (polarization direction component in the longitudinal direction of the line pattern) is emitted from the pattern of the grating (mask) R in a large amount. When a liquid is filled between the projection optical system PL and the resist applied to the wafer surface, the transmittance of diffracted light of the S-polarization component contributing to the improvement of the contrast on the grating surface is increased as compared with the case where air (gas) is filled between the projection optical system PL and the resist applied to the wafer surface, so that even when the Numerical Aperture (NA) of the projection optical system PL exceeds 1.0, high image forming performance can be obtained. Further, it is more effective to combine the phase shift mask with an oblique incident illumination method (a bipolar illumination method) along the longitudinal direction of the line pattern as disclosed in Japanese patent laid-open No. 6-188169.

In the exposure apparatus of the above embodiment, the light grating (mask) is illuminated by the illumination apparatus (illumination process), and the pattern for transfer formed on the mask is exposed on the photosensitive substrate by the projection optical system (exposure process), whereby the microdevice (semiconductor device, image pickup device, liquid crystal display device, thin film magnetic head, or the like) can be manufactured. Next, an example of a method for obtaining a semiconductor device as a microdevice by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate by using the exposure apparatus of the present embodiment will be described with reference to a flowchart of fig. 9.

First, in step 301 of fig. 20, a metal film is evaporated on 1 lot of wafers. In a next step 302, a photoresist is coated on the metal film on the 1 lot of wafers. Then, in step 303, the image of the pattern on the mask is sequentially exposed and transferred to the respective shot areas on the 1 lot of wafers by the exposure apparatus of the present embodiment through the projection optical system. Then, after the photoresist on the 1 lot of wafers is developed in step 304, a circuit pattern corresponding to the pattern on the mask is formed in each shot region on each wafer by etching the photoresist pattern on the 1 lot of wafers as a mask in step 305.

Then, by forming a circuit pattern on an upper layer, a semiconductor device or the like is manufactured. As described above, the semiconductor device having an extremely fine circuit pattern can be obtained with high productivity by the above-described semiconductor device manufacturing method. In steps 301 to 305, a metal is deposited on the wafer, a photoresist is applied to the metal film, and then each step of exposure, development, and etching is performed, but it is needless to say that a silicon oxide film is formed on the wafer before these steps, a photoresist is applied to the silicon oxide film, and then each step of exposure, development, and etching is performed.

In the exposure apparatus of the present embodiment, a liquid crystal display element as a microdevice can also be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, or the like) on a plate material (glass substrate). An example of this method will be described below with reference to the flowchart of fig. 21. In fig. 21, the pattern forming step 401 executes a photolithography step of transferring and exposing a pattern of a mask onto a photosensitive substrate (e.g., a glass substrate coated with a resist) by using the exposure apparatus of the present embodiment. By this photolithography process, a predetermined pattern including a plurality of electrodes and the like is formed on the photosensitive substrate. Then, the exposed substrate is subjected to various processes such as a developing process, an etching process, and a photoresist stripping process, thereby forming a predetermined pattern on the substrate, and is transferred to the next color filter forming process 402.

Next, the color filter forming process 402 forms a color filter in which a plurality of groups of 3 dots corresponding to R (red), G (green), and B (blue) are arranged in a matrix, or a plurality of groups of R, G, B of 3 band filters are arranged in the horizontal scanning line direction. Next, an element assembling process 403 is performed after the color filter forming process 402. In the element assembling step 403, a liquid crystal panel (liquid crystal element) is assembled using the substrate having the set pattern obtained in the pattern forming step 401, the color filter obtained in the color filter forming step 402, and the like. In the element assembling step 403, for example, liquid crystal is injected between the substrate having the set pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, thereby manufacturing a liquid crystal panel (liquid crystal element).

Then, in the module assembling step 404, the assembled liquid crystal panel (liquid crystal element) is mounted with various components such as an electric circuit and a backlight for performing a display operation, thereby completing the liquid crystal display element. As described above, the liquid crystal display element having an extremely fine circuit pattern can be obtained with high productivity by the above-described method for manufacturing a liquid crystal display element.

As described above, the projection optical system according to the 1 st aspect of the present invention employs a boundary lens including at least 2 mirrors and a surface on the 1 st surface side having a positive refractive power, and all of the transmission members and the reflection members are arranged along a single optical axis, and has a configuration of an effective imaging region not including the optical axis, and an optical path between the boundary lens and the 2 nd surface is filled with a medium having a refractive index larger than 1.1. As a result, the present invention can realize a relatively small projection optical system which can satisfactorily correct chromatic aberration and image curvature and has excellent imaging performance, and which can satisfactorily suppress reflection loss on an optical surface and secure a large effective image-side numerical aperture.

Further, as with the projection optical system pertaining to the 2 nd aspect of the present invention, since the intermediate image of the 1 st surface is formed in the 1 st imaging optical system, even in the case where the numerical aperture of the projection optical system is increased, the optical path separation of the light flux toward the 1 st surface side and the light flux toward the 2 nd surface side can be easily and reliably performed. Further, since the 1 st lens having a negative refractive power is provided in the 2 nd imaging optical system, the total length of the catadioptric projection optical system can be shortened, and adjustment for satisfying the petzval condition can be easily performed. In addition, the 1 st lens group alleviates the difference caused by the difference of the image viewing angles of the light beams expanded by the 1 st field lens, and suppresses the generation of aberration. Therefore, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, good imaging performance can be obtained over the entire exposure region.

Further, since the projection optical system according to the 3 rd aspect of the present invention includes at least 6 mirrors, even when the numerical apertures on the object side and the image side of the catadioptric projection optical system are increased in order to improve resolution, the 1 st intermediate image and the 2 nd intermediate image can be formed without increasing the total length of the catadioptric projection optical system. Therefore, the optical path separation of the light flux directed to the 1 st surface side and the light flux directed to the 2 nd surface side can be easily and reliably performed. Further, since the optical lens system includes at least 6 mirrors and the 2 nd lens group having negative refractive power, the petzval condition can be easily satisfied and aberration can be easily corrected by adjusting each mirror or the lens constituting the 2 nd lens group.

Further, as with the projection optical system according to the 3 rd aspect of the present invention, since it is an image forming system of 3 times, the 1 st intermediate image forms an inverted image of the 1 st surface, the 2 nd intermediate image forms an upright image of the 1 st surface, and the image formed on the 2 nd surface forms an inverted image. Therefore, when the catadioptric projection optical system of the present invention is mounted on an exposure apparatus and scanning exposure is performed on the 1 st surface and the 2 nd surface, the scanning direction of the 1 st surface and the scanning direction of the 2 nd surface can be made opposite to each other, and the change in the center of gravity of the entire exposure apparatus can be adjusted easily in a reduced manner. Further, by reducing the change in the center of gravity of the entire exposure apparatus, the vibration of the catadioptric projection optical system can be reduced, and excellent imaging performance can be obtained over the entire exposure apparatus.

Therefore, the exposure apparatus and the exposure method using the projection optical system according to the present invention can transfer and expose a fine pattern with high accuracy by the projection optical system having excellent image forming performance, a large effective image-side numerical aperture, and high resolution. Further, by using an exposure apparatus equipped with the projection optical system of the present invention, a favorable microdevice can be manufactured by high-precision projection exposure using a high-resolution projection optical system.

Claims

1. A projection optical system of a reflection-refraction type mounted on an exposure apparatus for forming a reduced image of an illumination pattern disposed on a 1 st surface on a substrate disposed on a 2 nd surface, the projection optical system comprising:

at least 2 lenses having positive refractive power, disposed between the 1 st surface and the 2 nd surface;

2 reflection mirrors disposed between the at least 2 lenses and the 2 nd surface, and sequentially reflecting the light from the 1 st surface via the at least 2 lenses;

an imaging optical system including a plurality of lenses disposed between the 2 mirrors and the 2 nd surface and an aperture stop disposed between the plurality of lenses, the imaging optical system forming the reduced image on the 2 nd surface by the light passing through the 2 mirrors;

the aforementioned plurality of lenses includes:

2 negative lenses disposed closer to the 1 st surface than the aperture stop, the 2 negative lenses being adjacent to each other;

at least 3 convex lenses disposed between the 2 negative lenses and the aperture stop; and

a boundary lens disposed closest to the 2 nd surface among the plurality of lenses, the 1 st surface side surface of the boundary lens having a positive refractive power;

the aforementioned 2 negative lenses comprise a biconcave lens;

the aforementioned at least 3 convex lenses include 2 biconvex lenses;

the imaging optical system forms the reduced image on the 2 nd surface in a state where a refractive index of an environment in an optical path of the projection optical system is 1 and an optical path between the boundary lens and the 2 nd surface is filled with a medium having a refractive index larger than 1.1;

all the transmission members and all the reflection members having power constituting the projection optical system are arranged along a single optical axis;

the imaging optical system forms the reduced image in an effective imaging region of a predetermined shape set in a region not including the optical axis in the 2 nd plane, and the mirror included in the projection optical system is constituted by only the 2 mirrors.

2. The projection optical system according to claim 1, characterized in that: the 2 negative lenses include a negative meniscus lens, and an exit pupil of the projection optical system has no blocking region.

3. The projection optical system according to claim 1, characterized in that: all the effective imaging areas that the aforementioned projection optical system has exist in the area away from the aforementioned optical axis.

4. The projection optical system according to claim 1, characterized in that:

comprises a 1 st imaging optical system including the at least 2 lenses and the 2 mirrors for forming an intermediate image of the pattern,

the imaging optical system for forming the reduced image forms the reduced image as a final image on the 2 nd surface based on the light from the intermediate image,

the aforementioned at least 3 convex lenses include at least 1 positive meniscus lens.

5. The projection optical system according to claim 4, characterized in that:

the 2-piece mirror includes a 1 st mirror disposed in an optical path of the at least 2 lenses and the intermediate image and a 2 nd mirror disposed in an optical path of the 1 st mirror and the intermediate image;

the aforementioned 2 lenticular lenses are arranged adjacent to each other.

6. The projection optical system according to claim 5, characterized in that:

the 1 st mirror is a concave mirror disposed in the vicinity of a pupil plane of the 1 st imaging optical system;

at least 1 negative lens is disposed in a reciprocating optical path formed by the concave reflecting mirror.

7. The projection optical system according to claim 6, characterized in that: the at least 1 negative lens and the boundary lens disposed in the optical path for reciprocal movement are formed of fluorite.

8. The projection optical system according to claim 5, characterized in that:

when the focal length of the 1 st lens group including the at least 2 lenses is F1 and the maximum image height on the 2 nd surface is Y0, the condition is satisfied

Condition 5< F1/Y0< 15.

9. The projection optical system according to claim 1, characterized in that: the at least 2 lenses have at least 2 positive lenses, and the at least 3 convex lenses include at least 1 positive meniscus lens.

10. The projection optical system according to claim 9, characterized in that: the imaging optical system forming the reduced image is a refractive optical system composed only of a plurality of transmission members, and the two lenticular lenses are arranged adjacent to each other.

11. The projection optical system according to claim 9, characterized in that: the transmission member constituting 70% or more of the number of transmission members of the imaging optical system forming the reduced image is formed of quartz.

12. The projection optical system according to claim 1, further comprising a light transmissive optical member substantially free of refractive power, disposed in an optical path between said boundary lens and said 2 nd surface.

13. An exposure apparatus for exposing a pattern formed on a mask on a photosensitive substrate,

it is characterized by comprising:

an illumination system for illuminating the pattern disposed on the 1 st surface;

the projection optical system according to any one of claims 1 to 12 for forming the pattern image illuminated by the illumination system on the photosensitive substrate disposed on the 2 nd surface.

14. The exposure apparatus according to claim 13, characterized in that: the illumination system supplies illumination light which is S-polarized to the 2 nd surface.

15. The exposure apparatus according to claim 13, characterized in that: and relatively moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system, and projection-exposing the pattern of the mask onto the photosensitive substrate.

16. An exposure method for exposing a pattern formed on a mask to a photosensitive substrate,

it is characterized by comprising:

an illumination process for illuminating the pattern disposed on the 1 st surface,

an exposure step of exposing the photosensitive substrate disposed on the 2 nd surface with the pattern image illuminated by the illumination step by the projection optical system according to any one of claims 1 to 12.

17. A method of manufacturing a micro-device, comprising:

an exposure step of exposing the photosensitive substrate provided on the 2 nd surface to the pattern of the mask provided on the 1 st surface by using the projection optical system according to any one of claims 1 to 12; and

a step of developing the photosensitive substrate exposed by the exposure step.