JPWO2005001544A1 - Optical unit, imaging optical system, aberration adjustment method of imaging optical system, projection optical system, manufacturing method of projection optical system, exposure apparatus, and exposure method - Google Patents

Abstract

A liquid configured to be attached to a dry imaging optical system that forms an image of an object through a gas, and for changing the image of the object to an immersion imaging optical system that forms through a liquid It is an optical unit for immersion change. This optical unit is replaced with an optical member disposed on the image side of an optical surface having a predetermined refractive power disposed on the most image side of the optical surfaces having a refractive power in the dry imaging optical system. At least one optical member provided in a possible manner is provided. Then, by replacing the optical member in the dry imaging optical system with the at least one optical member, the type of medium on the image side of the imaging optical system is changed from gas to liquid. Degradation of imaging characteristics of the imaging optical system caused by the occurrence is reduced.

Description

  The present invention relates to an imaging optical system, an aberration adjustment method for the imaging optical system, an exposure apparatus, and an exposure method, and more particularly to an exposure apparatus used when manufacturing a semiconductor element, a liquid product display element, and the like in a photolithography process. The present invention relates to a suitable projection optical system.

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

  As a result, in order to satisfy the demand for the resolution of the projection optical system, it is necessary to shorten the wavelength λ of the illumination light (exposure light) and increase the image-side numerical aperture NA of the projection optical system. Specifically, the resolution of the projection optical system is represented by k · λ / NA (k is a process coefficient). In addition, the image-side numerical aperture NA is defined such that the refractive index of a medium (usually a gas such as air) between the projection optical system and a photosensitive substrate (such as a wafer) is n, and the maximum incident angle on the photosensitive substrate is θ. Then, it is expressed by n · sin θ.

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

  In general, an immersion type imaging optical system in which immersion liquid is interposed between the object plane and the depth of focus and resolving power are improved compared to a normal dry type imaging optical system in which gas is interposed between the object plane and the object plane. . Further, when the immersion type imaging optical system (immersion type projection optical system) is used in the exposure apparatus, the resist reflectivity can be reduced as compared with the case where the dry type imaging optical system is used. Therefore, particularly in the case of an exposure apparatus, it is advantageous if the projection optical system can be switched between a dry type and an immersion type as required. However, in the conventional imaging optical system, when the switching is simply performed between the dry type and the liquid immersion type, the spherical aberration greatly fluctuates as described later.

  Accordingly, an object of the present invention is to enable switching between a dry type and an immersion type without substantially deteriorating the aberration state by a simple replacement operation of a few optical members. In addition, the present invention uses the imaging optical system that can be switched between a dry type and an immersion type without substantially deteriorating the aberration state, and performs good exposure with high resolution as necessary. An object of the present invention is to provide an exposure apparatus and an exposure method that can perform the same. Another object of the present invention is to provide an optical unit capable of switching the projection optical system between a dry type and an immersion type.

In order to achieve the above object, an imaging optical system according to a first aspect of the present invention is an immersion type imaging optical system having an immersion layer in contact with an image plane,
A first medium layer composed of a first medium, in order from the immersion layer side, between the optical surface having a predetermined refractive power disposed closest to the image surface and the immersion layer, and the first medium A second medium layer made of a second medium having a refractive index different from that of the first medium and a third medium layer made of a third medium having a refractive index different from that of the first medium and the second medium,
The boundary surface between the immersion layer and the first medium layer, the boundary surface between the first medium layer and the second medium layer, and the boundary surface between the second medium layer and the third medium layer are respectively flat. It is formed in the shape.

In order to achieve the above object, the imaging optical system according to the second aspect of the present invention has a refractive index between an optical surface having a predetermined refractive power disposed closest to the image surface and the image surface. An imaging optical system having four medium layers different from each other,
The radius of curvature of the boundary surface between two arbitrary medium layers adjacent to each other among the four medium layers is R, the maximum image height of the imaging optical system is Ym, and the optical surface having the predetermined refractive power When the radius of curvature is Rp,
Ym / | R | <0.01
Ym / | Rp |> 0.003
It satisfies the following conditions.

In order to achieve the above object, an imaging optical system according to a third aspect of the present invention includes a refractive index between a lens disposed closest to the image plane or the object plane and the image plane or the object plane. An imaging optical system having at least three medium layers different from each other,
The at least three medium layers each have no refractive power;
All the boundary surfaces in the at least three medium layers are formed in a planar shape.

In order to achieve the above-mentioned object, an adjustment method of an imaging optical system according to a fourth aspect of the present invention is an adjustment method of an imaging optical system that forms an image of an object,
An image-side medium changing step of changing the medium of the image-side medium layer, which is a medium layer between the most image-side optical surface on the most image side of the imaging optical system and the image plane, between gas and liquid;
A thickness along the optical axis of a first medium layer formed between the optical surface having a predetermined refractive power disposed closest to the image surface and the image-side medium layer, and the optical surface; A thickness along the optical axis of a second medium layer made of a second medium disposed between the surface and the first medium layer and having a refractive index different from that of the first medium layer, and the optical surface and the first medium layer. The medium in the image side space is changed by changing the thickness along the optical axis of the third medium layer disposed between the two medium layers and having a refractive index different from that of the first medium and the second medium. And an aberration correction step for correcting spherical aberration generated in the imaging optical system.

In order to achieve the above-mentioned object, an imaging optical system adjustment method according to a fifth aspect of the present invention is an imaging optical system adjustment method for forming an image of an object.
An image-side medium changing step of changing the medium of the image-side medium layer, which is a medium layer between the most image-side optical surface on the most image side of the imaging optical system and the image plane, between gas and liquid;
A first medium layer comprising a first medium disposed between the optical surface having a predetermined refractive power disposed closest to the image plane and the image-side medium layer; and the optical surface and the first medium layer. A second medium layer made of a second medium having a refractive index different from that of the first medium layer, and the first medium disposed between the optical surface and the second medium layer. And by changing at least one of the thickness and refractive index along the optical axis of the third medium layer having a refractive index different from that of the second medium to change the medium in the image side space. And an aberration correction step of correcting spherical aberration generated in the imaging optical system,
R is a radius of curvature of a boundary surface between two adjacent medium layers among the image side medium layer, the first medium layer, the second medium layer, and the third medium layer, and the imaging optics When the maximum image height of the system is Ym and the radius of curvature of the optical surface having the predetermined refractive power is Rp,
Ym / | R | <0.01
Ym / | Rp |> 0.003
It satisfies the following conditions.

  In order to achieve the above object, an exposure apparatus according to a sixth aspect of the present invention includes an illumination system for illuminating a mask, and a photosensitivity in which an image of a pattern formed on the mask is set on the image plane. And an imaging optical system according to any one of the first to third aspects for forming on a substrate.

  In order to achieve the above object, an exposure apparatus according to a seventh aspect of the present invention provides aberration adjustment by the aberration adjustment method according to the fourth aspect as a projection optical system for projecting and exposing a mask pattern onto a photosensitive substrate. The image forming optical system is provided.

  In order to achieve the above object, an exposure apparatus according to an eighth aspect of the present invention is adjusted by the adjustment method of the fifth aspect as a projection optical system for projecting and exposing a mask pattern onto a photosensitive substrate. An imaging optical system is provided.

  In order to achieve the above-described object, an exposure method according to a ninth aspect of the present invention illuminates a mask, and the pattern formed on the mask via the imaging optical system according to the first to third aspects is Projection exposure is performed on a photosensitive substrate set on an image plane.

  In order to achieve the above object, an exposure method according to a tenth aspect of the present invention is an image of a pattern formed on a mask using an imaging optical system whose aberration is adjusted by the aberration adjustment method of the fourth aspect. Is projected and exposed onto a photosensitive substrate.

  In order to achieve the above-mentioned object, an exposure method according to an eleventh aspect of the present invention is to sensitize a pattern image formed on a mask using an imaging optical system adjusted by the adjustment method of the fifth aspect. Projection exposure on a conductive substrate.

In order to achieve the above object, an optical unit according to a twelfth aspect of the present invention is configured to be attachable to a dry imaging optical system that forms an image of an object through a gas. An immersion-changing optical unit for changing to an immersion-type imaging optical system that forms a liquid via a liquid,
Among the optical surfaces having the refractive power in the dry-type imaging optical system, the optical surface is provided so as to be exchangeable with an optical member disposed on the image side of the optical surface having the predetermined refractive power disposed on the most image side. A first optical member formed of a first medium having a predetermined refractive index;
A second optical member provided in a replaceable manner with the optical member in the dry imaging optical system and formed of a second medium having a refractive index different from that of the first optical member;
At least one of the thickness along the optical axis of the first optical member and the refractive index of the first medium, and the thickness along the optical axis of the second optical member and the refractive index of the second medium. At least one of them is defined so as to correct spherical aberration generated due to the change of the type of the medium on the image side of the imaging optical system from gas to liquid. .

In order to achieve the above object, an optical unit according to a thirteenth aspect of the present invention is configured to be attachable to a dry imaging optical system that forms an image of an object through a gas, and An immersion-changing optical unit for changing to an immersion-type imaging optical system that forms a liquid via a liquid,
Among the optical surfaces having the refractive power in the dry-type imaging optical system, the optical surface is provided so as to be exchangeable with an optical member disposed on the image side of the optical surface having the predetermined refractive power disposed on the most image side. A first optical member formed of a first medium having a predetermined refractive index;
A second optical member provided in a replaceable manner with the optical member in the dry imaging optical system and formed of a second medium having a refractive index different from that of the first optical member;
An optical surface having the predetermined refractive power, where R is the radius of curvature of the two optical surfaces of the first optical member and the two optical surfaces of the second optical member, and Ym is the maximum image height of the imaging optical system. When the radius of curvature of Rp is Rp,
Ym / | R | <0.01
Ym / | Rp |> 0.003
It satisfies the following conditions.

In order to achieve the above-mentioned object, an optical unit according to a fourteenth aspect of the present invention forms a dry imaging optical system that forms an image of an object through a gas, and forms the image of the object through a liquid. An immersion-changing optical unit for changing to an immersion-type imaging optical system,
At least one exchangeable with an optical member disposed on the image side of the optical surface having a predetermined refractive power disposed on the most image side of the optical surfaces having a refractive power in the dry imaging optical system. An optical member,
This is because the type of medium on the image side of the imaging optical system is changed from gas to liquid by replacing the optical member in the dry imaging optical system with the at least one optical member. The deterioration of the imaging characteristics of the imaging optical system that occurs in this manner is reduced.

In order to achieve the above object, a projection optical system according to a fifteenth aspect of the present invention includes a plurality of optical elements, and uses an exposure light having a wavelength of 200 nm to 300 nm as a second surface image. A projection optical system formed above,
A first optical element disposed in the vicinity of the second surface and having a refractive power of approximately 0 on the second surface side;
A second optical element that is disposed closest to the second surface side and has a refractive power of approximately 0,
More than 80% of the plurality of optical elements are formed of the first glass material,
One of the first optical element and the second optical element is formed of the first glass material,
The other of the first optical element and the second optical element is formed of a second glass material having a lower refractive index than the first glass material,
The second surface side is telecentric.

In order to achieve the above-described object, a projection optical system according to a sixteenth aspect of the present invention includes a plurality of optical elements, and uses an exposure light having a wavelength of 200 nm to 300 nm as a second surface image. A projection optical system formed above,
A boundary lens disposed in the vicinity of the second surface and having a refractive power of approximately 0 on the second surface side;
A flat plate inserted in the vicinity of the second surface,
All of the plurality of optical elements excluding the plane plate are formed of the first glass material,
The flat plate is formed of a second glass material having a lower refractive index than the first glass material,
When the liquid interposed in the optical path between the boundary lens and the second surface is exchanged for gas, by adjusting the thickness of the boundary lens and the distance between the boundary lens and the plane plate, Maintaining substantially the same optical properties before and after the exchange of the liquid and the gas,
The second surface side is telecentric.

In order to achieve the above object, a projection optical system according to a seventeenth aspect of the present invention includes a plurality of optical elements, and uses an exposure light having a wavelength of 200 nm to 300 nm as a second surface image. A projection optical system formed above,
More than 80% of the plurality of optical elements are formed of the first glass material,
At least one optical element that is disposed in the vicinity of the second surface and is formed of a second glass material having a refractive index lower than that of the first glass material and has a refractive power of approximately 0 on the second surface side;
The second surface side is telecentric.

In order to achieve the above object, a projection optical system manufacturing method according to an eighteenth aspect of the present invention includes a plurality of optical elements, uses exposure light having a wavelength of 200 nm to 300 nm, and is telecentric on the second surface side. A projection optical system manufacturing method for forming an image of a first surface on the second surface under a simple light beam,
An optical element forming step of forming 80% or more of the plurality of optical elements with the first glass material;
A first optical element preparation step of preparing a first optical element that is formed of the first glass material and has a refractive power of about 0 on the second surface side;
A second optical element preparation step of preparing a second optical element formed of a second glass material having a refractive index lower than that of the first glass material and having a refractive power of approximately 0;
A first thickness adjusting step of adjusting the thickness of the first optical element disposed in the vicinity of the second surface;
A second thickness adjusting step for adjusting the thickness of the second optical element that is arranged closest to the second surface side,
In the first thickness adjusting step and the second thickness adjusting step, optical characteristics after a medium having a refractive index of 1.1 or more is interposed in the optical path between the second optical element and the second surface. The thicknesses of the first optical element and the second optical element are adjusted so as to maintain substantially the same optical characteristics as before the interposition.

In order to achieve the above object, a projection optical system manufacturing method according to a nineteenth aspect of the present invention includes a plurality of optical elements, uses exposure light having a wavelength of 200 nm to 300 nm, and is telecentric on the second surface side. A projection optical system manufacturing method for forming an image of a first surface on the second surface under a simple light beam,
An optical element preparation step of preparing a flat plate formed of a second glass material having a lower refractive index than the first glass material;
An insertion step of inserting the flat plate in the vicinity of the second surface;
A thickness adjusting step of adjusting a thickness of a boundary lens that is arranged closest to the second surface side and is formed of the first glass material and has a refractive power of approximately 0 on the second surface side;
An interval adjusting step of adjusting an interval between the planar plate inserted in the inserting step and the boundary lens,
The boundary plate is inserted in the insertion step, the thickness of the boundary lens is adjusted in the thickness adjustment step, and the interval between the plane plate and the boundary lens is adjusted in the interval adjustment step. Maintaining substantially the same optical characteristics before and after exchanging the liquid interposed in the optical path between the lens and the second surface with gas,
All of the plurality of optical elements excluding the flat plate are formed of a first glass material.

In order to achieve the above object, an exposure apparatus according to a twentieth aspect of the present invention is an exposure apparatus that transfers a mask pattern onto a photosensitive substrate.
An illumination optical system for illuminating the mask;
A projection optical system according to the fifteenth to seventeenth aspects for forming an image of the mask pattern on the photosensitive substrate;
It is characterized by providing.

In order to achieve the above object, an exposure apparatus according to a twenty-first aspect of the present invention is an exposure apparatus for transferring a mask pattern onto a photosensitive substrate,
An illumination optical system for illuminating the mask;
A projection optical system manufactured by the manufacturing method of the projection optical system according to the eighteenth or nineteenth aspect for forming an image of the mask pattern on the photosensitive substrate;
It is characterized by providing.

In order to achieve the above object, an exposure method according to a twenty-second aspect of the present invention is an exposure method for transferring a predetermined pattern onto a photosensitive substrate,
Illuminating a mask on which the predetermined pattern is formed; and
A projection step of projecting using the projection optical system according to the fifteenth to seventeenth aspects for forming the image of the predetermined pattern on the photosensitive substrate.

In order to achieve the above object, an exposure method according to a twenty-third aspect of the present invention is an exposure method for transferring a predetermined pattern onto a photosensitive substrate,
Illuminating a mask on which the predetermined pattern is formed; and
A projection step of projecting using the projection optical system manufactured by the projection optical system manufacturing method according to the eighteenth or nineteenth aspect for forming the image of the predetermined pattern on the photosensitive substrate. And

  In the present invention, it is possible to switch between the dry type and the liquid immersion type without substantially deteriorating the aberration state by a simple replacement operation of a few optical members. When switched to the immersion type, the depth of focus and resolution of the imaging optical system can be improved. In addition, when the imaging optical system switched to the immersion type is used in the exposure apparatus and the exposure method, the resist reflectance can be reduced.

  Therefore, the exposure apparatus and the exposure method of the present invention use an imaging optical system that can be switched between a dry type and an immersion type without substantially deteriorating the aberration state, so that high resolution can be achieved as necessary. Thus, good exposure can be performed, and as a result, a good microdevice can be manufactured.

FIG. 1 is a diagram schematically showing a main configuration of an image side and a spherical aberration diagram of a dry imaging optical system.
FIG. 2 is a diagram schematically showing a main configuration of an image side and a spherical aberration diagram when the dry imaging optical system shown in FIG. 1 is simply switched to an immersion type.
[FIG. 3] A schematic diagram of the image side main part configuration and spherical aberration diagram when the thickness of the plane-parallel plate and the gas layer is changed when the dry imaging optical system shown in FIG. 1 is switched to the immersion type. FIG.
[FIG. 4] Schematic diagram of main configuration of image side and spherical aberration diagram when thickness of parallel plane plate, gas layer and plano-convex lens is changed when switching the dry imaging optical system shown in FIG. 1 to the immersion type. FIG.
FIG. 5 is a diagram schematically showing a main configuration of an image side of an optical system optically equivalent to the immersion type imaging optical system shown in FIG.
FIG. 6 is a drawing schematically showing a configuration of an exposure apparatus including an imaging optical system according to the first embodiment of the present invention.
FIG. 7 is a diagram schematically showing a lens configuration of the projection optical system of the present embodiment set to an immersion type.
FIG. 8 is a diagram schematically showing the main configuration of the image side of the immersion type projection optical system shown in FIG.
FIG. 9 is a diagram corresponding to FIG. 8 and schematically showing the main configuration of the image side of the dry projection optical system of the present embodiment.
FIG. 10 is a diagram showing transverse aberration in the immersion type projection optical system of the present embodiment.
FIG. 11 is a diagram showing transverse aberration in the dry projection optical system of the present embodiment.
FIG. 12 is a flowchart showing an example of a technique for manufacturing the immersion type projection optical system of the present embodiment.
FIG. 13 is a diagram schematically showing a main configuration of a wavefront aberration measuring apparatus used when manufacturing the immersion type projection optical system of the present embodiment.
FIG. 14 is a diagram showing a lens configuration of a projection optical system according to a second embodiment.
FIG. 15 is a diagram showing a lens configuration of a part of the projection optical system according to the second embodiment.
FIG. 16 is a diagram showing a lens configuration of a projection optical system according to a third embodiment.
FIG. 17 is a diagram showing a lens configuration of a part of the projection optical system according to the third embodiment.
FIG. 18 is a diagram showing a lens configuration of a projection optical system according to a fourth embodiment.
FIG. 19 is a diagram showing a lens configuration of a part of a projection optical system according to a fourth embodiment.
FIG. 20 is a flowchart for explaining a projection optical system manufacturing method according to the fifth embodiment.
FIG. 21 is a diagram showing a lens configuration of a part of the projection optical system manufactured by the projection optical system manufacturing method according to the fifth embodiment.
FIG. 22 is a diagram showing a lens configuration of a part of the projection optical system manufactured by the projection optical system manufacturing method according to the fifth embodiment.
FIG. 23 is a flowchart for explaining a projection optical system manufacturing method according to the sixth embodiment.
FIG. 24 is a view showing the schematic arrangement of an exposure apparatus according to a sixth embodiment.
FIG. 25 is a lateral aberration diagram showing transverse aberration in the meridional direction and sagittal direction of the dry projection optical system according to the example 1;
FIG. 26 is a transverse aberration diagram showing transverse aberration in the meridional direction and sagittal direction of the immersion type projection optical system according to Example 1.
FIG. 27 is a lateral aberration diagram showing transverse aberration in the tangential direction and sagittal direction of the dry projection optical system according to the second example.
FIG. 28 is a lateral aberration diagram showing lateral aberration in the tangential direction and sagittal direction of the immersion type projection optical system according to Example 2.
FIG. 29 is a lateral aberration diagram showing transverse aberration in the tangential direction and sagittal direction of the dry projection optical system according to the example 3;
FIG. 30 is a lateral aberration diagram showing lateral aberration in the tangential direction and sagittal direction of the immersion type projection optical system according to Example 3.
FIG. 31 is a flowchart of a method for obtaining a semiconductor device as a micro device.
FIG. 32 is a flowchart of a method for obtaining a liquid crystal display element as a micro device.

  FIG. 1 is a diagram schematically showing a main configuration of an image side and a spherical aberration diagram of a dry imaging optical system. The dry imaging optical system shown in FIG. 1 has a refractive index different from that of the plane parallel gas layer 1, the plane parallel plate 2, the plane parallel gas layer 3, and the plane parallel plate 2 in this order from the image plane I side. And a plano-convex lens 4 having a plane on the image plane I side and a convex surface A on the object plane side. In the dry imaging optical system shown in FIG. 1, spherical aberration is corrected well. 1 to 4, the vertical axis represents the image-side numerical aperture NA.

  FIG. 2 is a diagram schematically showing a main configuration of the image side and a spherical aberration diagram when the dry imaging optical system shown in FIG. 1 is simply switched to the immersion type. The optical system shown in FIG. 2 is an immersion type imaging optical system obtained by filling the optical path between the image plane I of the dry type imaging optical system shown in FIG. is there. Accordingly, the immersion type imaging optical system shown in FIG. 2 includes, in order from the image plane I side, a parallel plane immersion liquid layer 5, a parallel plane plate 2, a parallel plane gas layer 3, and a plano-convex lens 4. It is out. As a result, in the immersion type imaging optical system shown in FIG. 2, the focal position is displaced, and spherical aberration occurs at the displaced focal position.

  FIG. 3 schematically shows an image side main part configuration and spherical aberration diagram when the thickness of the plane parallel plate and the gas layer is changed when the dry imaging optical system shown in FIG. 1 is switched to the immersion type. FIG. The optical system shown in FIG. 3 replaces the plane parallel plate 2 of the dry imaging optical system shown in FIG. 1 with a plane parallel plate 2a having a different thickness and changes the optical path between the image plane I and the plane parallel plate 2a. It is an immersion type imaging optical system obtained by filling with immersion liquid.

  Therefore, the immersion type imaging optical system shown in FIG. 3 includes a parallel plane immersion liquid layer 5, a parallel plane plate 2a, a parallel plane gas layer 3a, and a plano-convex lens 4 in this order from the image plane I side. It is out. In this case, since only the thicknesses of the plane parallel plate 2a and the plane parallel gas layer 3a are adjusted, the positional deviation of the focal position does not occur, but the spherical aberration cannot be corrected well, Some spherical aberration remains.

  FIG. 4 is a schematic diagram of the principal part of the image side and the spherical aberration diagram when the thickness of the parallel plane plate, the gas layer, and the plano-convex lens is changed when the dry imaging optical system shown in FIG. 1 is switched to the immersion type. FIG. The optical system shown in FIG. 4 replaces the parallel plane plate 2 and the plano-convex lens 4 of the dry imaging optical system shown in FIG. 1 with parallel plane plates 2 b and plano-convex lenses 4 a having different thicknesses and is parallel to the image plane I. This is an immersion type imaging optical system obtained by filling the optical path between the flat plate 2b with immersion liquid.

  Accordingly, the immersion type imaging optical system shown in FIG. 4 includes, in order from the image plane I side, a parallel plane immersion liquid layer 5, a plane parallel plate 2b, a plane parallel gas layer 3b, and a plano-convex lens 4a. It is out. In this case, since the thicknesses of the plane parallel plate 2b, the plane parallel gas layer 3b, and the plano-convex lens 4a are respectively adjusted, the spherical aberration is corrected well without causing the positional deviation of the focal position.

  FIG. 5 is a diagram schematically showing the main configuration of the image side of an optical system that is optically equivalent to the immersion type imaging optical system shown in FIG. In the immersion type imaging optical system shown in FIG. 5, the plano-convex lens 4a in the immersion type imaging optical system shown in FIG. 4 is divided into a plano-convex lens 4b and a parallel plane plate 4c, and the gas layer 3b is divided into two parallel planes. The gas layers 3c and 3d are divided. Therefore, in the immersion type imaging optical system shown in FIG. 5, in parallel from the image plane I side, the parallel plane immersion liquid layer 5, the parallel plane plate 4c, the parallel plane gas layer 3c, the parallel plane plate 2b, and the parallel plane. A planar gas layer 3d and a plano-convex lens 4b are included.

  Here, the plano-convex lens 4b and the plane parallel plate 4c are formed of the same optical material. The plane parallel plate 2b is formed of an optical material having a refractive index different from that of the plano-convex lens 4b and the plane parallel plate 4c. In the immersion type imaging optical system shown in FIG. 5, the plano-convex lens 4a is divided into the plano-convex lens 4b and the plane-parallel plate 4c, but the combined thickness is the same as in FIG. The same as the immersion type imaging optical system shown in FIG.

  As described above, the optical system in FIG. 4 is an immersion type imaging optical system having the immersion layer 5 (image-side medium layer) in contact with the image plane I, and is disposed closest to the image plane I. A plane-parallel plate 2b (first optical member) and a plane-parallel gas are disposed between the optical surface having a predetermined refractive power, that is, the convex surface A of the plano-convex lens 4a and the immersion layer 5 in this order from the immersion layer 5 side. It has a layer 3b and a plano-convex lens 4a (second optical member). Here, the plane parallel plate 2b is a first medium layer made of a first optical material (solid) as a first medium, and the gas layer 3b is a gas as a second medium having a refractive index different from that of the first medium. The plano-convex lens 4a is a third medium layer made of a second optical material (solid) as a third medium having a refractive index different from that of the first medium and the second medium.

  The boundary surface between the immersion liquid layer 5 and the parallel flat plate 2b as the first medium layer, the boundary surface between the parallel flat plate 2b as the first medium layer and the gas layer 3b as the second medium layer, and the second The boundary surfaces between the gas layer 3b, which is a medium layer, and the plano-convex lens 4a, which is a third medium layer, are each formed in a planar shape. In this case, as described above, the thickness along the optical axis of the plane parallel plate 2b as the first medium layer, the thickness along the optical axis of the gas layer 3b as the second medium layer, and the third medium layer By changing (adjusting) the thickness of the plano-convex lens 4a along the optical axis, the refractive index of the medium between the imaging optical system and the image plane I is changed, thereby forming an image. Spherical aberration occurring in the optical system can be corrected without affecting other aberrations of the imaging optical system.

  Thus, in the imaging optical system of the present invention having the image side main part configuration as shown in FIG. 4, the parallel plane plate 2b and the plano-convex lens 4a are replaced with a plane parallel plate and a plano-convex lens having appropriate thicknesses. That is, it is possible to switch between the dry type and the liquid immersion type without substantially deteriorating the aberration state by a simple exchange operation of a few optical members. When switched to the immersion type, the depth of focus and resolution of the imaging optical system can be improved. In addition, when the imaging optical system switched to the immersion type is used in the exposure apparatus and the exposure method, the resist reflectance can be reduced. As a result, the exposure apparatus and the exposure method using the imaging optical system of the present invention that can be switched between the dry type and the immersion type without substantially deteriorating the aberration state can achieve high resolution as necessary. Good exposure can be performed.

  In the above description, the boundary surface between the immersion liquid layer 5 and the parallel flat plate 2b that is the first medium layer, and the boundary surface between the parallel flat plate 2b that is the first medium layer and the gas layer 3b that is the second medium layer. The surface and the boundary surface between the gas layer 3b as the second medium layer and the plano-convex lens 4a as the third medium layer are each formed in a planar shape. However, the present invention is not limited to this, and other modes are possible. That is, according to another aspect of the present invention, four medium layers having different refractive indexes are provided between an optical surface A having a predetermined refractive power and disposed closest to the image surface I, and the image surface I. The present invention can be applied to an imaging optical system in which the curvature of the boundary surface between two arbitrary medium layers adjacent to each other among the four medium layers is very small.

  However, the radius of curvature of the boundary surface between two arbitrary medium layers adjacent to each other among the four medium layers is R, the maximum image height of the imaging optical system is Ym, and the optical surface A having a predetermined refractive power When the curvature radius is Rp, it is necessary to satisfy the conditions of Ym / | R | <0.01 (conditional expression 1) and Ym / | Rp |> 0.003 (conditional expression 2). In the case of the imaging optical system shown in FIG. 4, the four medium layers having different refractive indexes correspond to the immersion layer 5, the plane parallel plate 2b, the gas layer 3b, and the plano-convex lens 4a. Therefore, in this aspect, the planar optical surfaces of the plane parallel plate 2b and the plano-convex lens 4a may be optical surfaces with a small curvature that satisfy the conditional expression 1. In order to achieve the effect of the present invention more satisfactorily, it is preferable to set the upper limit value of conditional expression 1 and the lower limit value of conditional expression 2 to 0.007. In this mode, spherical aberration is corrected without affecting other aberrations of the imaging optical system by changing the thickness along the optical axis in at least three of the four medium layers. can do.

  Further, according to another aspect of the present invention, a refraction is made between a lens (plano-convex lens 4a in FIG. 4) disposed closest to the image plane (or object plane) I and the image plane (or object plane) I. An imaging optical system having at least three medium layers (in FIG. 4, the immersion layer 5, the plane parallel plate 2b, and the gas layer 3b) having different rates, and each of the at least three medium layers has no refractive power; The present invention can be applied to an optical system in which all boundary surfaces in at least three medium layers are formed in a planar shape. In this aspect, by changing at least one of the thickness and refractive index along the optical axis in at least three medium layers, spherical aberration can be reduced without affecting other aberrations of the imaging optical system. It can be corrected.

  In the present invention, the difference in refractive index between two arbitrary media having different refractive indexes is preferably 0.01 or more. With this configuration, a sufficient correction effect for spherical aberration can be expected. Further, it is preferable that the imaging optical system is substantially telecentric on the image plane side. With this configuration, for example, when the present invention is applied to an exposure apparatus and an exposure method, high-precision exposure can be performed without substantially changing the magnification even if the photosensitive substrate is slightly displaced in the optical axis direction. it can.

Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 6 is a drawing schematically showing a configuration of an exposure apparatus including the imaging optical system according to the first embodiment of the present invention. In the present embodiment, the present invention is applied to the projection optical system PL of the exposure apparatus. 6, the Z axis is parallel to the optical axis AX of the projection optical system PL, the Y axis is parallel to the paper surface of FIG. 6 in the plane perpendicular to the optical axis AX, and the X axis is perpendicular to the paper surface of FIG. 6. It is set.

  The illustrated exposure apparatus includes an ArF excimer laser light source (oscillation center wavelength 193.306 nm) as the light source 100 for supplying illumination light in the ultraviolet region. The light emitted from the light source 100 uniformly illuminates the reticle R on which a predetermined pattern is formed via the illumination optical system IL. The optical path between the light source 100 and the illumination optical system IL is sealed with a casing (not shown), and the space from the light source 100 to the optical member on the most reticle side in the illumination optical system IL absorbs exposure light. It is replaced with an inert gas such as helium gas or nitrogen, which is a low-rate gas, or is kept in a substantially vacuum state.

  The reticle R is held parallel to the XY plane on the reticle stage RS via the reticle holder RH. A pattern to be transferred is formed on the reticle R, and a rectangular (slit-like) pattern region having a long side along the X direction and a short side along the Y direction is illuminated in the entire pattern region. Is done. Reticle stage RS can be moved two-dimensionally along the reticle plane (ie, XY plane) by the action of a drive system (not shown), and its position coordinates are measured by interferometer RIF using reticle moving mirror RM. And the position is controlled.

  Light from the pattern formed on the reticle R forms a reticle pattern image on the wafer W, which is a photosensitive substrate, via the projection optical system PL. The wafer W is held parallel to the XY plane on the wafer stage WS via a wafer table (wafer holder) WT. Then, a rectangular still exposure having a long side along the X direction and a short side along the Y direction on the wafer W so as to optically correspond to the rectangular illumination region on the reticle R. A pattern image is formed in the area (that is, the effective exposure area).

  The wafer stage WS can be moved two-dimensionally along the wafer surface (that is, the XY plane) by the action of a drive system (not shown), and its position coordinates are measured by an interferometer WIF using a wafer moving mirror WM. In addition, the position is controlled. In the illustrated exposure apparatus, the optical member (specifically, the lens L1) disposed closest to the reticle among the optical members constituting the projection optical system PL and the optical member (specifically, positioned closest to the wafer). Is configured such that the interior of the projection optical system PL is kept airtight with the plane parallel plate P3 or P2a), and the gas inside the projection optical system PL is replaced with nitrogen.

  Further, a reticle R and a reticle stage RS are arranged in a narrow optical path between the illumination optical system IL and the projection optical system PL, but a casing (not shown) that hermetically surrounds the reticle R and the reticle stage RS. Is filled with nitrogen. A narrow optical path between the projection optical system PL and the wafer W includes a wafer W and a wafer stage WS. The inside of a casing (not shown) that hermetically encloses the wafer W and the wafer stage WS. Is filled with nitrogen. Thus, an atmosphere in which exposure light is hardly absorbed is formed over the entire optical path from the light source 100 to the wafer W.

  As described above, the illumination area on the reticle R and the effective exposure area on the wafer W defined by the projection optical system PL are rectangular with short sides along the Y direction. Accordingly, the reticle stage RS is controlled along the short side direction of the rectangular exposure area and the illumination area, that is, the Y direction, while controlling the positions of the reticle R and the wafer W using a drive system and an interferometer (RIF, WIF). By moving (scanning) the wafer stage WS and thus the reticle R and the wafer W synchronously along the Y direction, the wafer W has a width equal to the long side of the effective exposure region and the wafer W. A reticle pattern is scanned and exposed on a shot area having a length corresponding to the scanning amount (movement amount).

  FIG. 7 is a diagram schematically showing the lens configuration of the projection optical system of the present embodiment set to the immersion type. FIG. 8 is a diagram schematically showing the main configuration of the image side of the immersion type projection optical system shown in FIG. 7 and 8, the immersion type projection optical system according to this embodiment includes, in order from the reticle side, a plane parallel plate P1, a plano-concave lens L1 having an aspheric concave surface facing the wafer side, and a reticle. A negative meniscus lens L2 with a concave surface facing the side, a positive meniscus lens L3 with an aspheric concave surface facing the reticle side, a positive meniscus lens L4 with a concave surface facing the reticle side, and a flat surface facing the reticle side A convex lens L5, a plano-convex lens L6 having a plane facing the wafer side, a positive meniscus lens L7 having a convex surface facing the reticle side, a positive meniscus lens L8 having an aspherical concave surface facing the wafer side, and a convex surface facing the reticle side , Negative meniscus lens L10 having a convex surface on the reticle side, and negative meniscus lens L having an aspheric concave surface on the wafer side 1, a biconcave lens L12, a negative meniscus lens L13 having an aspherical concave surface facing the reticle, a biconvex lens L14, a planoconcave lens L15 having an aspherical concave surface facing the wafer, and a concave surface on the reticle side A positive meniscus lens L16 with a convex surface facing the reticle side, a positive meniscus lens L17 with a convex surface facing the reticle side, an aperture stop AS, a biconcave lens L18, a biconvex lens L19, and a positive meniscus lens L20 with a concave surface facing the reticle side, A positive meniscus lens L21 having a convex surface facing the reticle, a positive meniscus lens L22 having a convex surface facing the reticle, a positive meniscus lens L23 having an aspheric concave surface facing the wafer, and a convex surface facing the reticle. A positive meniscus lens L24, a plano-convex lens L25 having a convex surface facing the reticle, a parallel plane plate P2, and a parallel plane It is constituted by a P3. The optical path between the plane parallel plate P3 and the wafer W is filled with an immersion liquid made of pure water.

In the present embodiment, the height of the aspheric surface in the direction perpendicular to the optical axis is y, and the distance (sag amount) along the optical axis from the tangent plane at the apex of the aspheric surface to the position on the aspheric surface at height y. ) was is z, a vertex radius of curvature is r, a conical coefficient is kappa, when the n-th order aspherical coefficient was C _n, is expressed by the following equation (a). In the following table (1), a lens surface formed in an aspherical shape is marked with * on the right side of the surface number.

z = (y ² / r) / [1+ {1- (1 + κ) · y ² / r ² } ^1/2 ]
-C ₄ · y ⁴ + C ₆ · y ⁶ + C ₈ · y ⁸ + C ₁₀ · y ¹⁰
+ C ₁₂ · y ¹² + C ₁₄ · y ¹⁴ (a)

In this embodiment, the optical member (lens component and parallel plane plate) constituting the immersion projection optical system is formed of quartz (SiO ₂ ) or fluorite (CaF ₂ ). Specifically, the positive meniscus lens L24, the plano-convex lens L25, and the plane parallel plate P3 are made of fluorite, and the other optical members are made of quartz. The oscillation center wavelength of ArF excimer laser light as exposure light is 193.306 nm, the refractive index of quartz with respect to this central wavelength (relative refractive index with respect to nitrogen) is 1.5603261, and the refractive index of fluorite ( The relative refractive index with respect to nitrogen is 1.5014548. Further, as the immersion liquid interposed between the plane parallel plate P3 and the wafer W, pure water having a refractive index of 1.43664 (relative refractive index with respect to nitrogen) with respect to the exposure light is used.

  The following table (1) lists the values of specifications of the immersion type projection optical system according to the present embodiment. In Table (1), λ is the center wavelength of the exposure light, β is the projection magnification, NA is the image side (wafer side) numerical aperture, Ym is the maximum image height, and LX is along the X direction of the effective exposure region. LY represents a dimension (long side dimension), and LY represents a dimension along the Y direction of the effective exposure region (short side dimension). The surface number is the order of the surfaces from the reticle side, r is the radius of curvature of each surface (vertical radius of curvature: mm in the case of an aspherical surface), and d is the axial distance between the surfaces, that is, the surface interval (mm). Respectively. The notation in Table (1) is the same in the following Table (2).

（ウェハ面）
（非球面データ）
４面
κ＝０
Ｃ_４＝−１．１１１７７×１０^−７ Ｃ_６＝３．３４６１７×１０^−１２
Ｃ_８＝−１．４７６１４×１０^−１６ Ｃ_１０＝５．１５６８１×１０^−２１
Ｃ_１２＝６．３３６７３×１０^２５ Ｃ_１４＝−５．５８６３８×１０^−２９
７面
κ＝０
Ｃ_４＝５．１１７６２×１０^−９ Ｃ_６＝−１．１２４６９×１０^−１３
Ｃ_８＝−５．６１９７８×１０^−１８ Ｃ_１０＝３．２０５３８×１０^−２２
Ｃ_１２＝８．５０６７６×１０^−２７ Ｃ_１４＝−６．２０６４１×１０^−３１
１８面
κ＝０
Ｃ_４＝６．１６１５５×１０^−８ Ｃ_６＝−１．２２１２６×１０^−１２
Ｃ_８＝６．８７３９４×１０^−１７ Ｃ_１０＝−２．３７００６×１０^−２１
Ｃ_１２＝９．７１４９４×１０^−２６ Ｃ_１４＝−７．９３９８５×１０^−３１
２４面
κ＝０
Ｃ_４＝−９．２７５１４×１０^−８ Ｃ_６＝１．６５８１２×１０^−１２
Ｃ_８＝−２．０１９３６×１０^−１６ Ｃ_１０＝２．９５８５０×１０^−２１
Ｃ_１２＝−１．６６４１５×１０^−２５ Ｃ_１４＝−１．４９３４５×１０^−２８
２７面
κ＝０
Ｃ_４＝２．９１４００×１０^−８ Ｃ_６＝１．３０９２５×１０^−１２
Ｃ_８＝５．１６３９８×１０^−１７ Ｃ_１０＝６．９５５６２×１０^−２１
Ｃ_１２＝−１．２８７３０×１０^−２５ Ｃ_１４＝８．７５２９１×１０^−２９
３２面
κ＝０
Ｃ_４＝４．０７６６６×１０^−８ Ｃ_６＝−２．９７２５１×１０^−１３
Ｃ_８＝−７．５９００７×１０^−１８ Ｃ_１０＝２．１７４３６×１０^−２２
Ｃ_１２＝３．０３５０１×１０^−２８ Ｃ_１４＝−６．８２６１９×１０^−３２
４９面
κ＝０
Ｃ_４＝４．３２６１７×１０^−９ Ｃ_６＝１．０９５１１×１０^−１３
Ｃ_８＝−１．８３２９６×１０^−１７ Ｃ_１０＝８．４２１４１×１０^−２２
Ｃ_１２＝−２．９９７１７×１０^−２６ Ｃ_１４＝７．８１７０８×１０^−３１
（条件式対応値）
Ｒ＝∞
Ｙｍ＝１３．７３ｍｍ
Ｒｐ＝２９５５．５ｍｍ
（条件式１）Ｙｍ／｜Ｒ｜＝０
（条件式２）Ｙｍ／｜Ｒｐ｜＝０．００４６

(Wafer surface)
(Aspheric data)
4 sides κ = 0
C ₄ = −1.111177 × 10 ⁻⁷ C ₆ = 3.334617 × 10 ⁻¹²
C ₈ = −1.47614 × 10 ⁻¹⁶ C ₁₀ = 5.15681 × 10 ⁻²¹
C ₁₂ = 6.33673 × 10 ²⁵ C ₁₄ = −5.58638 × 10 ⁻²⁹
7 surfaces κ = 0
C ₄ = 5.11762 × 10 ⁻⁹ C ₆ = −1.14469 × 10 ⁻¹³
C ₈ = −5.61978 × 10 ⁻¹⁸ C ₁₀ = 3.220538 × 10 ⁻²²
C ₁₂ = 8.50676 × 10 ⁻²⁷ C ₁₄ = −6.20641 × 10 ⁻³¹
18 faces κ = 0
C ₄ = 6.16155 × 10 ⁻⁸ C ₆ = −1.22126 × 10 ⁻¹²
C ₈ = 6.887394 × 10 ⁻¹⁷ C ₁₀ = −2.37006 × 10 ⁻²¹
C ₁₂ = 9.77144 × 10 ⁻²⁶ C ₁₄ = −7.99395 × 10 ⁻³¹
24 surfaces κ = 0
C ₄ = −9.27514 × 10 ⁻⁸ C ₆ = 1.65812 × 10 ⁻¹²
C ₈ = −2.01936 × 10 ⁻¹⁶ C ₁₀ = 2.95850 × 10 ⁻²¹
C ₁₂ = −1.66415 × 10 ⁻²⁵ C ₁₄ = −1.49345 × 10 ⁻²⁸
27 faces κ = 0
C ₄ = 2.91400 × 10 ⁻⁸ C ₆ = 1.30925 × 10 ⁻¹²
C ₈ = 5.16398 × 10 ⁻¹⁷ C ₁₀ = 6.995562 × 10 ⁻²¹
C ₁₂ = −1.28730 × 10 ⁻²⁵ C ₁₄ = 8.75291 × 10 ⁻²⁹
32 faces κ = 0
^{_{C 4 = 4.07666 × 10 -8 C}} 6 = -2.97251 × 10 -13
C ₈ = −7.59007 × 10 ⁻¹⁸ C ₁₀ = 2.17436 × 10 ⁻²²
C ₁₂ = 3.03501 × 10 ⁻²⁸ C ₁₄ = −6.882619 × 10 ⁻³²
49 faces κ = 0
C ₄ = 4.332617 × 10 ⁻⁹ C ₆ = 1.09511 × 10 ⁻¹³
C ₈ = −1.83296 × 10 ⁻¹⁷ C ₁₀ = 8.41411 × 10 ⁻²²
C ₁₂ = −2.99717 × 10 ⁻²⁶ C ₁₄ = 7.881708 × 10 ⁻³¹
(Values for conditional expressions)
R = ∞
Ym = 13.73mm
Rp = 2955.5mm
(Condition 1) Ym / | R | = 0
(Condition 2) Ym / | Rp | = 0.0046

  As shown in FIG. 8, in the immersion type projection optical system of the present embodiment, a parallel plane pure water layer (immersion layer) having a thickness of 1.0 mm and fluorite are sequentially formed from the wafer W side. A plane parallel plate P3 having a thickness of 20.0 mm, a plane parallel nitrogen layer (gas layer) having a thickness of 9.0 mm, a plane parallel plate P2 having a thickness of 5.3034 mm made of quartz, and a thickness of 1.4973 mm It includes a plane-parallel nitrogen layer and a plano-convex lens L25 having a thickness of 19.7001 mm formed of fluorite. In the present embodiment, a dry projection optical system is obtained by replacing the plano-convex lens L25 and parallel plane plate P3 of the immersion type projection optical system with a plano-convex lens L25a and replacing the plane parallel plate P2 with a plane parallel plate P2a. .

  FIG. 9 is a diagram corresponding to FIG. 8, and is a diagram schematically showing the main configuration of the image side of the dry projection optical system of the present embodiment. Comparing FIG. 8 and FIG. 9, when switching from the immersion type to the dry type, a planoconvex lens L25 having a thickness of 19.70001 mm formed of fluorite and a parallel of 20.0 mm having a thickness of fluorite are formed. The flat plate P3 is changed to a plano-convex lens L25a having a thickness of 41.995 mm, which is also formed of fluorite. Further, the plane parallel plate P2 having a thickness of 5.3034 mm formed of quartz is changed to a plane parallel plate P2a having a thickness of 4.0 mm which is also formed of quartz.

  As a result, in the dry projection optical system of the present embodiment, in parallel from the wafer W side, a parallel plane nitrogen layer having a thickness of 9.0 mm, a parallel plane plate P2a having a thickness of 4.0 mm formed of quartz, A plane-parallel nitrogen layer having a thickness of 1.5 mm and a plano-convex lens L25a having a thickness of 41.995 mm formed of fluorite are included. The configuration from the reticle R to the convex surface on the reticle side of the plano-convex lens L25 or L25a is common to the immersion type and the dry type. The following table (2) lists the values of the specifications of the dry projection optical system according to the present embodiment. However, in Table (2), the display of the common part with the immersion type projection optical system is omitted.

（ウェハ面）
（条件式対応値）
Ｒ＝∞
Ｙｍ＝１３．７３ｍｍ
Ｒｐ＝２９５５．５ｍｍ
（条件式１）Ｙｍ／｜Ｒ｜＝０
（条件式２）Ｙｍ／｜Ｒｐ｜＝０．００４６

(Wafer surface)
(Values for conditional expressions)
R = ∞
Ym = 13.73mm
Rp = 2955.5mm
(Condition 1) Ym / | R | = 0
(Condition 2) Ym / | Rp | = 0.0046

  FIG. 10 is a diagram showing lateral aberration in the immersion type projection optical system of the present embodiment. FIG. 11 is a diagram showing lateral aberration in the dry projection optical system of the present embodiment. In the aberration diagrams, Y indicates the image height. Referring to the aberration diagrams of FIGS. 10 and 11, in this embodiment, various aberrations including spherical aberration are satisfactorily corrected in both the immersion type and the dry type, and the spherical aberration is changed when switching from the immersion type to the dry type. It can be seen that fluctuations in various aberrations including are small.

  In the above description, the present invention has been described by taking the switching from the immersion type to the dry type as an example. However, the switching from the dry type to the immersion type is also possible. That is, by changing the plano-convex lens L25a to the plano-convex lens L25 and the plane parallel plate P3 and changing the plane parallel plate P2a to the plane parallel plate P2, it is possible to switch from the dry type to the liquid immersion type. In this case, it is apparent with reference to the aberration diagrams of FIGS. 10 and 11 that fluctuations in various aberrations including spherical aberration are small when switching from the dry type to the liquid immersion type. In the present embodiment, the projection optical system PL is substantially telecentric on both the reticle side and the wafer side in both the immersion type and the dry type.

  As described above, in the projection optical system (imaging optical system) PL of the present embodiment, the plano-convex lens L25a, the plano-convex lens L25, and the plane parallel plate P3 are exchanged, and the plane parallel plate P2a and the plane parallel plate P2 are exchanged. By doing so, it is possible to switch between the dry type and the liquid immersion type without substantially deteriorating the aberration state by a simple replacement operation of a few optical members. As a result, in the exposure apparatus of this embodiment, the projection optical system PL that can be switched between the dry type and the liquid immersion type without substantially deteriorating the aberration state can be used to achieve high resolution as necessary. Good exposure can be performed.

  Next, with reference to FIG. 12 and FIG. 13, an example of a manufacturing method of the immersion type projection optical system listed in Table (1) will be described. First, the dry projection optical system shown in Table (2) is manufactured (step 101). Here, for manufacturing a dry projection optical system, reference can be made to, for example, Japanese Patent Application Laid-Open No. 2002-258131 (and corresponding European Patent Publication No. 1359608).

Next, the plano-convex lens L25a and the plane-parallel plate P2a in the dry-type projection optical system are removed from the dry-type projection optical system, and instead, the plano-convex lens L25, the plane-parallel plate P3 and the plane-parallel plate P2 are incorporated into the projection optical system. (Step 102).
Then, the aberration of the projection optical system in which the planoconvex lens L25, the plane parallel plate P3 and the plane parallel plate P2 are incorporated is measured using the wavefront aberration measuring apparatus shown in FIG. 13 (step 103).

  FIG. 13 is a diagram schematically showing the configuration of a Fizeau interferometer-type wavefront aberration measuring instrument that measures the wavefront aberration of the projection optical system PL. As shown in FIG. 13, a laser beam having substantially the same wavelength as the exposure light is incident on the projection optical system PL as the test optical system via the half prism 60 and the Fizeau surface 61a of the Fizeau lens 61. At this time, the light reflected by the Fizeau surface 61 a becomes so-called reference light, and reaches the image sensor 62 such as a CCD via the Fizeau lens 61 and the half prism 60.

On the other hand, the light transmitted through the Fizeau surface 61 a becomes so-called measurement light, is emitted through the projection optical system 6, passes through the correction glass 64, and then enters the reflection spherical surface 63.
The correction glass 64 is made of an optical material such as synthetic quartz or fluorite having a high transmittance with respect to the wavelength of the measurement light. The correction glass 64 is formed in a parallel plate shape for the following two reasons. First, even if the correction glass 64 is arranged in a state of being laterally displaced in the plane orthogonal to the optical axis of the projection optical system, the amount of aberration generated in the correction glass 64 does not change depending on the amount of lateral displacement of the correction glass 64. Second, the aberration generated in the correction glass 64 does not change according to the arrangement position in the optical axis direction.

  Since the projection optical system that has undergone step 102 is used as an immersion type projection optical system, the substrate to be exposed is separated from the projection optical system by an interval of about several millimeters, and the projection optical system and the substrate are separated from each other. Exposure transfer is performed in a state where a liquid is supplied therebetween. In the case where the liquid is pure water, the refractive index of pure water and the correction glass 64 formed of fluorite are approximately the same for light with a wavelength of 193 nm. For this reason, the thickness of the correction glass 64 is about several millimeters, and is optimized in consideration of the difference between the refractive index of the correction glass 64 and the refractive index of the liquid. As long as the correction glass 64 is between the projection optical system PL and the reflection member 63, the position of the correction glass 64 is not limited. However, on the image plane of the projection optical system PL, there is a possibility that the optical intensity of the measurement light increases and optical correction of the correction glass 64 may occur. It is preferable to do.

The measurement light reflected by the reflective spherical surface 63 reaches the CCD 62 via the correction glass 64, the projection optical system PL, the Fizeau lens 61, and the half prism 60. Thus, the wavefront aberration remaining in the projection optical system PL is measured based on the interference between the reference light and the measurement light.
As described above, in the wavefront aberration measuring apparatus of FIG. 13, even when the image plane side of the projection optical system is in a dry state, aberration can be generated by the correction glass 64 and the aberration state in the liquid immersion state can be measured.

  Next, based on the measurement result of the wavefront aberration obtained in step 103, the position in the optical axis direction of a part of the lens in the projection optical system, the posture with respect to the optical axis, or the position in the optical axis direction of the mask is adjusted. Then, the aberration of the projection optical system PL is adjusted (step 104). By repeating the operations of steps 103 and 104 until the aberration of the projection optical system is corrected, it is possible to manufacture the projection optical system in which the aberration is corrected in the liquid immersion state.

  In the above-described embodiment, nitrogen is filled into the projection optical system PL, the casing that encloses the reticle R and the reticle stage RS, and the casing that encloses and surrounds the wafer W and the wafer stage WS. Yes. However, the present invention is not limited to this, and the inside of the projection optical system PL and the inside of the casing may be filled with an inert gas such as helium gas, or may be kept in a substantially vacuum state.

  Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 14 is a diagram showing a lens configuration of a projection optical system according to the second embodiment of the present invention. The projection optical system PL1 according to the second embodiment includes a plurality of optical elements L1 to L24, and uses the exposure light having a wavelength of 200 nm to 300 nm to generate a pattern image of the mask M1 located on the first surface. It is formed on the wafer W1 located on the second surface. The projection optical system PL1 is configured so that the image side (that is, the wafer W1 side) is telecentric.

  The projection optical system PL1 includes, in order of exposure light passing from the object side (that is, the mask M1 side), a plane parallel plate L1, a negative meniscus lens L2 having an aspherical surface on the image side, and a plane on the image side. A plano-concave lens L3, a positive meniscus lens L4 with a concave surface facing the object side, a positive meniscus lens L5 with a concave surface facing the object side, a biconvex lens L6, a biconvex lens L7, and a positive meniscus lens L8 with a convex surface facing the object side A negative meniscus lens L9 with a convex surface facing the object side, a negative meniscus lens L10 with a concave surface formed aspherical on the image side, a biconcave lens L11, a plano-concave lens L12 with a plane facing the image side, and an image side Bi-concave lens L13 with a concave surface formed in an aspherical shape, positive meniscus lens L14 with a concave surface facing the object side, plano-convex lens L15 with the plane facing the object side, biconvex lens L16 Aperture stop AS1, biconcave lens L17, biconvex lens L18, biconvex lens L19, positive meniscus lens L20 having a convex surface on the object side, positive meniscus lens L21 having an aspheric surface on the image side, and on the object side The lens includes a positive meniscus lens L22 having a convex surface, a plane parallel plate (first optical element) L23, and a plane parallel plate (second optical element) L24.

  Here, the lenses L1 to L23 are made of quartz glass (synthetic quartz) which is the first glass material, and the lens L24 is made of fluorite which is the second glass material having a lower refractive index than the first glass material. In other words, 80% or more of the plurality of optical elements constituting the projection optical system PL1 are formed of quartz glass, and at least one of the plurality of optical elements constituting the projection optical system PL1 is a fluorescent light. It is made of stone. Note that the refractive power of the image side surface of the plane parallel plate L23 disposed in the vicinity of the wafer W1 is 0, but the refractive power of the image side surface of the plane parallel plate L23 may be substantially zero. Further, the refractive power of the plane parallel plate L24 arranged closest to the wafer W1 is 0, but the refractive power of the plane parallel plate L24 may be substantially zero.

  FIG. 15A shows a positive meniscus lens L22, a plane parallel plate L23, a plane parallel plate L24 and a wafer W1 included in a dry projection optical system PL1 in which a gas is interposed between the plane parallel plate L24 and the wafer W1. It is a figure which shows schematic structure. In the dry projection optical system PL1 shown in FIG. 15A, the spherical aberration is corrected well.

  FIG. 15B shows an immersion type in which the plane parallel plate L24 is retracted and a liquid (medium) E1 having a refractive index of 1.1 or more is interposed in the optical path between the plane parallel plate L23 and the wafer W1. It is a figure which shows schematic structure of the positive meniscus lens L22, the plane parallel plate L23, and wafer W1 which are contained in projection optical system PL1. In the immersion type projection optical system PL1 shown in FIG. 15B, the distance between the positive meniscus lens L22 and the plane parallel plate L23 and the thickness of the plane parallel plate L23 are increased as compared with the dry type. Yes. Further, the thickness of the plane parallel plate L24 is set to 0 by retracting the plane parallel plate L24 from the optical path of the exposure light. That is, the thickness of the plane parallel plate L24 is reduced as compared with the dry type. In the immersion type projection optical system PL1 shown in FIG. 15B, the spherical aberration is corrected well by adjusting the distance between the positive meniscus lens L22 and the plane parallel plate L23 and the thickness of the plane parallel plate L23. ing. That is, the optical characteristics of the dry-type projection optical system PL1 shown in FIG. 15A and the optical characteristics of the immersion-type projection optical system PL1 shown in FIG. 15B are maintained almost the same.

  According to the projection optical system PL1 according to the second embodiment, the thickness of the plane parallel plate L23 is increased and the thickness of the plane parallel plate L24 is decreased (in this embodiment, the plane parallel plate L24 is retracted). By adjusting the distance between the parallel plane plate L23 and the parallel plane plate L24, the gas between the projection optical system PL1 and the wafer W1 is changed into a liquid. Even in the case of switching, the optical characteristics of the projection optical system PL1 before and after switching can be maintained substantially the same without deteriorating the spherical aberration of the projection optical system PL1. In the projection optical system PL1 switched to the immersion type, the depth of focus and the resolution can be improved. In addition, when the projection optical system PL1 according to this embodiment is used in an exposure apparatus, the resist reflectance can be reduced. Further, when the projection optical system PL1 switched to the dry type is used in an exposure apparatus, exposure can be performed with high throughput.

  In the second embodiment, the plane-parallel plate L23 is provided as the first optical element, but a lens having a refractive power of approximately 0 on the wafer W1 side may be provided as the first optical element. Good. Further, the dry projection optical system PL1 includes a parallel plane plate L23 formed of quartz glass as the first optical element and a plane parallel plate L24 formed of fluorite as the second optical element. You may make it provide the 1st optical element formed by (2) and the 2nd optical element formed with quartz glass.

  Further, the immersion type projection optical system PL1 shown in FIG. 15B can be replaced with a dry type projection optical system PL1 shown in FIG. In this case, the plane parallel plate (plane plate) L24 is inserted closest to the wafer W1 or in the vicinity of the wafer W1, and gas is interposed between the plane parallel plate L24 and the wafer W1. Further, the thickness of the plane parallel plate L23 is decreased, and the distance between the plane parallel plate L23 and the plane parallel plate L24 is adjusted. Also in this case, by reducing the thickness of the plane parallel plate L23 and adjusting the distance between the plane parallel plate L23 and the plane parallel plate L24, the optical before and after the replacement from the immersion type to the dry type projection optical system. The characteristics can be kept almost the same.

  Next, a third embodiment of the present invention will be described with reference to the drawings. FIG. 16 is a diagram showing a lens configuration of a projection optical system according to the third embodiment of the present invention. The projection optical system PL2 according to the third embodiment includes a plurality of optical elements L31 to L57, and uses the exposure light having a wavelength of 200 nm to 300 nm to generate a pattern image of the mask M2 located on the first surface. It is formed on the wafer W2 located on the second surface. The projection optical system PL2 is configured so that the image side (that is, the wafer W2 side) is telecentric.

  The projection optical system PL2 according to the third embodiment includes a biconcave lens in which the parallel plane plate L31 and the concave surface formed in an aspherical shape are directed to the image side in the order in which light rays pass from the object side (that is, the mask M2 side). L32, a positive meniscus lens L33 having a convex surface facing the object side, a negative meniscus lens L34 having a concave surface facing the object side, a positive meniscus lens L35 having a concave surface facing the object side, a biconvex lens L36, and a positive surface having a convex surface facing the object side A meniscus lens L37, a positive meniscus lens L38 having a convex surface facing the object side, a positive meniscus lens L39 having a convex surface facing the object side, a negative meniscus lens L40 having a convex surface facing the object side, and an aspheric surface formed on the object side. A negative meniscus lens L41 with a convex surface, a biconcave lens L42 with an aspheric surface facing the object side, and a concave surface formed with an aspheric surface on the image side A biconcave lens L43, a biconcave lens L44 having an aspheric surface facing the image side, a positive meniscus lens L45 having a concave surface facing the object side, a positive meniscus lens L46 having a concave surface facing the object side, and a biconvex lens L47. , Aperture stop AS2, biconcave lens L48, biconvex lens L49, positive meniscus lens L50 with a convex surface facing the object side, positive meniscus lens L51 with a convex surface facing the object side, positive meniscus lens L52 with a convex surface facing the object side, image A negative meniscus lens L53 having an aspheric surface facing the aspherical surface, a biconcave lens L54 having an aspheric surface facing the image side, a planoconvex lens L55 having a convex surface facing the object side, and a plane-parallel plate (First optical element) L56 and a plane parallel plate (second optical element) L57.

  Here, the lenses L31 to L53 and L57 are formed of quartz glass (synthetic quartz) as the first glass material, and the lenses L54 to L56 are formed of fluorite as the second glass material having a lower refractive index than the first glass material. ing. That is, 80% or more of the plurality of optical elements constituting the projection optical system PL2 are made of quartz glass, and at least one of the plurality of optical elements constituting the projection optical system PL2 is fluorescent. It is made of stone. Further, the refractive power of the image side surface of the plane parallel plate L56 disposed in the vicinity of the wafer W2 is 0, but the refractive power of the image side surface of the plane parallel plate L56 may be substantially zero. In addition, the refractive power of the plane parallel plate L57 disposed closest to the wafer W2 is 0, but the refractive power of the plane parallel plate L57 may be approximately 0.

  FIG. 17A schematically shows a plano-convex lens L55, a plane parallel plate L56, a plane parallel plate L57, and a wafer W2 included in a dry projection optical system PL2 in which a gas is interposed between the plane parallel plate L57 and the wafer W2. It is a figure which shows a structure. In the dry projection optical system PL2 shown in FIG. 17A, the spherical aberration is corrected well.

  FIG. 17B is a plan view included in an immersion type projection optical system PL2 in which a liquid (medium) E2 having a refractive index of 1.1 or more is interposed in the optical path between the plane parallel plate L57 and the wafer W2. It is a figure which shows schematic structure of the convex lens L55, the plane parallel plate L56, the plane parallel plate L57, and the wafer W2. In the immersion type projection optical system PL2 shown in FIG. 17B, the thickness of the plane parallel plate L56 is reduced as compared with the dry type. Further, the thickness of the plane parallel plate L57 is increased as compared with the dry type. In the immersion type projection optical system PL2 shown in FIG. 17B, the spherical aberration is favorably corrected by reducing the thickness of the plane parallel plate L56 and increasing the thickness of the plane parallel plate L57. . That is, the optical characteristics of the dry projection optical system PL2 shown in FIG. 17A and the optical characteristics of the immersion type projection optical system PL2 shown in FIG.

  According to the projection optical system PL2 according to the third embodiment, the thickness of the plane parallel plate L56 is decreased, and the thickness of the plane parallel plate L57 is increased to increase the distance between the projection optical system PL2 and the wafer W2. Even when the medium is switched, the optical characteristics of the projection optical system PL2 before and after switching can be maintained substantially the same without deteriorating the spherical aberration of the projection optical system PL2. In the projection optical system PL2 switched to the immersion type, the depth of focus and the resolution can be improved. In addition, when the projection optical system PL2 according to this embodiment is used in an exposure apparatus, the resist reflectance can be reduced. Further, when the projection optical system PL2 switched to the dry type is used in an exposure apparatus, exposure can be performed with high throughput.

  Further, according to the projection optical system PL2 according to the third embodiment, since the optical element arranged closest to the wafer W2 is the parallel flat plate L57 formed of quartz glass, it is an immersion type. Even when the projection optical system PL2 is replaced, the parallel plane plate L57 can be prevented from being eroded by the liquid E2.

  In the third embodiment, the plane-parallel plate L56 is provided as the first optical element, but a lens having a refractive power of about 0 on the wafer W2 side may be provided as the first optical element. Good. The projection optical system PL2 includes a plane parallel plate L56 formed of fluorite as the first optical element and a plane parallel plate L57 formed of quartz glass as the second optical element, but is formed of quartz glass. The first optical element and the second optical element formed of fluorite may be provided.

  Further, the immersion type projection optical system PL2 shown in FIG. 17B can be replaced with a dry type projection optical system PL2 shown in FIG. In this case, the thickness of the plane parallel plate L56 is increased, the thickness of the plane parallel plate L57 is decreased, and a gas is interposed between the plane parallel plate L57 and the wafer W2. Also in this case, by increasing the thickness of the plane parallel plate L56 and decreasing the thickness of the plane parallel plate L57, the optical characteristics before and after replacement from the liquid immersion type to the dry type projection optical system are made substantially the same. Can be maintained.

  Next, a fourth embodiment of the present invention will be described with reference to the drawings. FIG. 18 is a diagram showing a lens configuration of a projection optical system according to the fourth embodiment of the present invention. The projection optical system PL3 according to the fourth embodiment includes a plurality of optical elements L61 to L86, and uses the exposure light having a wavelength of 200 nm to 300 nm to generate a pattern image of the mask M3 located on the first surface. It is formed on the wafer W3 located on the second surface. The projection optical system PL3 is configured so that the image side (that is, the wafer W3 side) is telecentric.

  The projection optical system PL3 according to the fourth embodiment includes a bi-concave lens in which a parallel plane plate L61 and a concave surface formed in an aspheric shape are directed to the image side in the order in which light rays pass from the object side (that is, the mask M3 side). L62, a positive meniscus lens L63 having a convex surface facing the object side, a negative meniscus lens L64 having a concave surface facing the object side, a positive meniscus lens L65 having a concave surface facing the object side, a biconvex lens L66, and a positive surface having a convex surface facing the object side A meniscus lens L67, a positive meniscus lens L68 having a convex surface facing the object side, a positive meniscus lens L69 having a convex surface facing the object side, a negative meniscus lens L70 having a convex surface facing the object side, and an aspheric surface formed on the object side. A negative meniscus lens L71 facing the convex surface, a biconcave lens L72 facing the concave surface formed aspherical on the object side, and a concave surface formed aspherical on the image side A biconcave lens L73, a plano-concave lens L74 having an aspheric surface facing the image side, a positive meniscus lens L75 having a concave surface facing the object side, a positive meniscus lens L76 having a concave surface facing the object side, and a biconvex lens L77. , Aperture stop AS3, negative meniscus lens L78 having a convex surface facing the object side, positive meniscus lens L79 having a concave surface facing the object side, positive meniscus lens L80 having a convex surface facing the object side, positive meniscus lens having a convex surface facing the object side A lens L81, a positive meniscus lens L82 having a convex surface facing the object side, a negative meniscus lens L83 having a concave surface formed aspherical on the image side, and a biconcave lens having a concave surface formed aspherical on the image side L84, a plano-convex lens (first optical element) L85 having a convex surface facing the object side, and a plane parallel plate (second optical element) L86.

  Here, the lenses L61 to L85 are made of quartz glass (synthetic quartz) as the first glass material, and the lens L86 is made of fluorite as the second glass material having a lower refractive index than the first glass material. That is, 80% or more of the plurality of optical elements constituting the projection optical system PL3 are made of quartz glass, and at least one of the plurality of optical elements constituting the projection optical system PL3 is fluorescent. It is made of stone. Note that the refractive power of the image side surface of the plano-convex lens L85 disposed in the vicinity of the wafer W3 is 0, but the refractive power of the image side surface of the plano-convex lens L85 may be substantially zero. Further, the refractive power of the plane parallel plate L86 arranged closest to the wafer W3 is 0, but the refractive power of the plane parallel plate L86 may be substantially zero.

  FIG. 19A is a diagram showing a schematic configuration of a plano-convex lens L85, a plane parallel plate L86, and a wafer W3 included in a dry projection optical system PL3 in which a gas is interposed between the plane parallel plate L86 and the wafer W3. is there. In the dry projection optical system PL3 shown in FIG. 19A, spherical aberration is corrected well.

  In FIG. 19B, the parallel plane plate L86 formed of fluorite is replaced with a parallel plane plate L86 ′ formed of quartz glass, and the refractive index is in the optical path between the parallel plane plate L86 ′ and the wafer W3. It is a figure which shows schematic structure of the plano-convex lens L85, parallel plane plate L86 ', and wafer W3 which are included in the immersion type projection optical system PL3 which interposed the liquid (medium) E3 which is 1.1 or more. In the immersion type projection optical system PL3 shown in FIG. 19B, the thickness of the plane parallel plate L86 'is reduced as compared with the plane parallel plate L86 provided in the dry type projection optical system PL3. Further, the interval between the plano-convex lens L85 and the plane-parallel plate L86 'is increased as compared with the interval between the plano-convex lens L85 and the plane-parallel plate L86 provided in the dry projection optical system PL3. In the projection optical system PL3 in the case of the immersion type shown in FIG. 19B, the thickness of the plane-parallel plate L86 ′ is increased, and the distance between the plano-convex lens L85 and the plane-parallel plate L86 ′ is adjusted, thereby correcting the spherical surface. The aberration is corrected well. That is, the optical characteristics of the dry-type projection optical system PL3 shown in FIG. 19A and the optical characteristics of the immersion-type projection optical system PL3 shown in FIG. 19B are maintained almost the same.

  According to the projection optical system PL3 according to the fourth embodiment, the plane-parallel plate L86 formed of fluorite is replaced with the plane-parallel plate L86 ′ formed of quartz glass, and the plano-convex lens L85 and the plane-parallel plate are exchanged. Even when the gas between the projection optical system PL3 and the wafer W3 is switched to a liquid by adjusting the distance to L86 ′, the projection optical system PL3 before and after the switching is not deteriorated without deteriorating the spherical aberration of the projection optical system PL3. These optical characteristics can be maintained substantially the same. In the projection optical system PL3 switched to the immersion type, the depth of focus and the resolution can be improved. In addition, when the projection optical system PL3 according to this embodiment is used in an exposure apparatus, the resist reflectance can be reduced. Further, when the projection optical system PL3 switched to the dry type is used in an exposure apparatus, exposure can be performed with high throughput.

  Further, according to the projection optical system PL3 according to the fourth embodiment, when the projection optical system PL3 is replaced with the immersion type projection optical system PL3, the plane parallel plate formed by the fluorite arranged closest to the wafer W3. Since L86 is replaced with a plane parallel plate L86 ′ formed of quartz glass, it is possible to prevent the plane parallel plate L86 ′ from being eroded by the liquid E3.

  In the fourth embodiment, the plano-convex lens L85 is provided as the first optical element. However, an optical element, for example, a parallel plane plate, whose refractive power on the wafer W3 side is substantially 0 is used as the first optical element. You may make it prepare. The dry projection optical system PL3 includes a plano-convex lens L85 formed of quartz glass as a first optical element and a plane parallel plate L86 formed of fluorite as a second optical element. You may make it provide the 2nd optical element comprised by the 1st optical element and quartz glass to be formed.

  As described above, in the projection optical systems according to the second to fourth embodiments, the first optical element constituted by a lens or a plane parallel plate having a refractive power on the second surface side of substantially zero, and the refractive power. Is provided with a second optical element that is substantially 0, one of the first optical element and the second optical element is formed of the first glass material, and the other has a lower refractive index than the first glass material. It is formed of the second glass material. Accordingly, even when the second optical element disposed closest to the second surface side and the second surface are switched to a gas or liquid having a different refractive index, the thicknesses of the first optical element and the second optical element are reduced. By adjusting, the optical characteristics of the projection optical system before and after switching can be maintained substantially the same. Further, when the optical element formed of the second glass material having a refractive index lower than that of the first glass material is arranged at a position where the energy of the exposure light is concentrated, the optical element is damaged by strong energy and the projection optical system Degradation of optical characteristics can be prevented.

  In the projection optical systems according to the second to fourth embodiments, since the second optical element is formed of the second glass material having a lower refractive index than the first glass material, it is disposed on the second surface most. Even when switching between the optical element and the second surface from gas to liquid, the projection optical before and after switching is increased by increasing the thickness of the first optical element and decreasing the thickness of the second optical element. The optical properties of the system can be kept substantially the same. Further, when the second optical element is arranged at a position where the energy of the exposure light is concentrated, damage to the second optical element and deterioration of the optical characteristics of the projection optical system due to strong energy can be prevented.

  Further, in the projection optical systems according to the second to fourth embodiments, the second optical element and the second optical element are reduced by a small modification that increases the thickness of the first optical element and decreases the thickness of the second optical element. It is possible to maintain substantially the same optical characteristics as before the optical characteristics after the medium having a refractive index of 1.1 or more is interposed in the optical path between the second surface and the second surface.

  In addition, the projection optical systems according to the second to fourth embodiments include the boundary lens formed of the first glass material having the refractive power on the second surface side of approximately 0, and the refractive power is approximately 0. A flat plate formed of a second glass material having a lower refractive index than the first glass material is inserted in the vicinity of the second surface. Therefore, even when the liquid interposed in the optical path between the boundary lens and the second surface is exchanged for gas, a small modification is made to adjust the thickness of the boundary lens and the distance between the boundary lens and the inserted flat plate. Thus, the optical characteristics of the projection optical system before and after the exchange between the liquid and the gas can be maintained substantially the same.

  The projection optical system according to the second to fourth embodiments includes a plurality of optical elements, and 80% or more of the plurality of optical elements are formed of the first glass material. At least one optical element that is formed of a second glass material having a refractive index lower than that of the glass material and has a refractive power of approximately 0 on the second surface side is provided. Therefore, when the optical element formed of the second glass material is disposed at a position where the energy of the exposure light is concentrated, damage to the optical element due to strong energy and deterioration of the optical characteristics of the projection optical system can be prevented. .

Next, a fifth embodiment of the present invention will be described with reference to the drawings. FIG. 20 is a flowchart showing a projection optical system manufacturing method according to the fifth embodiment.
First, 80% or more of the plurality of optical elements constituting the projection optical system are formed of synthetic quartz (first glass material) (step S200). Next, a plano-convex lens (first optical element) made of synthetic quartz and having a refractive power of 0 on the image surface (second surface) side is prepared (step S201). Here, the plano-convex lens prepared in step S201 may have a refractive power of approximately zero. Then, the plano-convex lens prepared in step S201 is disposed in the vicinity of the image plane (step S202). Next, a plane parallel plate (second optical element) that is formed of fluorite (second glass material) having a refractive index lower than that of synthetic quartz and has a refractive power of 0 is prepared (step S203). Here, the plane parallel plate prepared in step S203 may have a refractive power of almost zero. Then, the plane parallel plate prepared in step S203 is disposed closest to the image plane (step S204).

  FIG. 21A is a diagram showing a schematic configuration of the plano-convex lens L90 arranged in step S202 and the plane-parallel plate L91 arranged in step S204 in the projection optical system manufactured by the processes of steps S200 to S204. is there. As shown in FIG. 21A, the plano-convex lens L90 is disposed in the vicinity of the image plane W, and the parallel plane plate L91 is disposed closest to the image plane W. In the projection optical system manufactured in this embodiment, when a gas is interposed between the plane-parallel plate L91 and the image plane W, the exposure plane having a wavelength of 200 nm to 300 nm is used. An image of an object (first surface) (not shown) is formed on the image plane W under a telecentric light beam on the side.

  Next, the thickness of the plano-convex lens L90 disposed in the vicinity of the image plane W in step S202 is adjusted (step S205). Specifically, adjustment is performed by increasing the thickness of the plano-convex lens. Next, the thickness of the plane parallel plate L91 arranged closest to the image plane W in step S204 is adjusted (step S206). Specifically, the adjustment is performed by reducing the thickness of the plane parallel plate L91.

  FIG. 21B shows a plano-convex lens L90 whose thickness is adjusted in step S205 of the projection optical system manufactured by steps S200 to S206, and a parallel flat plate L91 whose thickness is adjusted in step S207. It is a figure which shows schematic structure. As shown in FIG. 21B, when a medium E10 such as pure water having a refractive index of 1.1 or more is interposed in the optical path between the plane parallel plate L91 and the image plane W, the plano-convex lens L90 in step S205. Is adjusted to increase the thickness of the parallel plane plate L91 in step S206, and is adjusted to decrease the thickness of the plane parallel plate L91, so that the optical characteristics after the medium E10 is interposed are almost the same as the optical characteristics before the optical characteristics are interposed. Can be maintained.

  According to the projection optical system manufacturing method according to the fifth embodiment, the plane-parallel plate L91 is obtained by a simple method of increasing the thickness of the plano-convex lens L90 and decreasing the thickness of the plane-parallel plate L91. It is possible to maintain substantially the same optical characteristics as before the optical characteristics after the medium E10 is interposed in the optical path between the image plane and the image plane. Also, the dry projection optical system can be easily replaced with an immersion type projection optical system while maintaining the optical characteristics of the projection optical system.

  In the fifth embodiment, the plano-convex lens L90 is prepared as the first optical element. However, an optical element made of synthetic quartz and having a refractive power of about 0 on the image plane side, such as a plane parallel plate, is used. You may prepare.

  In addition, when the medium E10 is a medium that easily erodes fluorite, it is not preferable that the parallel flat plate L91 formed of fluorite and the medium E10 come into contact with each other. In this case, after the dry projection optical system is manufactured in steps S200 to S204, the plane parallel plate L91 disposed closest to the image plane W in step S204 is retracted from the optical path of the exposure light (retraction). Process). By retracting the plane parallel plate L91, the thickness of the plane parallel plate L91 is reduced to zero. Next, in step S202, the thickness of the plano-convex lens L90 disposed in the vicinity of the image plane W is adjusted. Specifically, adjustment is performed by increasing the thickness of the plano-convex lens.

  FIG. 22 is a diagram showing a schematic configuration of a plano-convex lens L90 in which the plane-parallel plate L91 is retracted from the projection optical system manufactured by the processes of steps S200 to S204 and the thickness is adjusted. When a medium E10 such as pure water having a refractive index of 1.1 or more is interposed in the optical path between the plano-convex lens L90 and the image plane W as shown in FIG. By performing the adjustment to increase the thickness of L90, it is possible to maintain almost the same optical characteristics as before the optical characteristics after the medium E10 is interposed.

  In the fifth embodiment, after a projection optical system optimum for the dry type is manufactured, a medium such as pure water is provided between the projection optical system and the image plane while maintaining the optical characteristics of the dry type. The projection optical system that is optimal for the immersion type that uses E10 is manufactured. After the projection optical system that is optimal for the immersion type is manufactured, the projection optical system is maintained while maintaining the optical characteristics of the immersion type. A medium having a refractive index of 1.1 or more interposed between the image plane and the image plane may be exchanged with a gas to produce a projection optical system optimal for the dry type. In this case, when the manufactured immersion type projection optical system includes the parallel plane plate L91 formed of fluorite, the thickness of the plano-convex lens 90 formed of quartz glass is reduced, and the fluorite The adjustment to increase the thickness of the plane parallel plate L91 formed by the above is performed. On the other hand, when the manufactured immersion type projection optical system does not include the parallel plane plate L91 formed of fluorite, the parallel plane plate L91 formed of fluorite is prepared and inserted into the projection optical system. . Next, adjustment is performed to reduce the thickness of the plano-convex lens 90 formed of quartz glass.

Next, a sixth embodiment of the present invention will be described with reference to the drawings. FIG. 23 is a flowchart showing a method for manufacturing the projection optical system according to the sixth embodiment.
First, a plurality of optical elements, all of which are made of synthetic quartz (first glass material), are used with exposure light having a wavelength of 200 nm to 300 nm, under a telecentric light beam on the image surface (second surface) side. A projection optical system for forming a pattern image on the object side on the image plane is prepared (step S300). Here, in the projection optical system prepared in step S300, spherical aberration is favorably corrected when a liquid is interposed between the projection optical system and the image plane.

  Next, a flat plate made of fluorite (second glass material) having a refractive index lower than that of synthetic quartz and having a refractive power of 0 is prepared (step S301). Here, the planar plate prepared in step S301 may have a refractive power of almost zero. Next, the flat plate prepared in step S301 is inserted in the vicinity of the image plane of the projection optical system prepared in step S300 (step S302).

  Next, the thickness of the boundary lens provided in the projection optical system prepared in step S300 and arranged closest to the image plane side is adjusted (step S303). Here, the boundary lens is formed of quartz glass, and the refractive power of the image-side surface is 0, but the refractive power of the boundary-side image-side surface may be approximately 0. Specifically, the adjustment of the thickness of the boundary lens in step S303 is performed by reducing the thickness of the boundary lens. Next, the interval between the plane plate inserted in step S302 and the boundary lens is adjusted (step S304).

  According to the method for manufacturing a projection optical system according to the sixth embodiment, a flat plate is inserted in step S302, adjustment is performed to reduce the thickness of the boundary lens in step S303, and the flat plate in step S304. Even when the liquid intervened in the optical path between the boundary lens and the image plane is replaced with a gas by a simple method of adjusting the distance between the boundary lens and the boundary lens, the optical characteristics before and after the replacement are changed. It can be kept almost the same. Further, the immersion type projection optical system can be easily replaced with a dry type projection optical system while maintaining the optical characteristics of the projection optical system.

  In the sixth embodiment, the thickness of the boundary lens is adjusted in step S302, and the distance between the plane plate and the boundary lens is adjusted in step S303. May be adjusted to adjust the thickness of the boundary lens. Further, the adjustment of the thickness of the boundary lens and the adjustment of the distance between the flat plate and the boundary lens may be performed alternately.

  In the sixth embodiment, the thickness of the boundary lens included in the immersion type projection optical system is adjusted to replace the dry type projection optical system, but a replacement boundary lens is prepared. Then, by replacing the boundary lens included in the immersion type projection optical system with the prepared boundary lens, the lens may be replaced with a dry type projection optical system. That is, in step S301, a plane plate and a replacement boundary lens are prepared (exchange boundary lens preparation step). Here, the replacement boundary lens is made of quartz glass, and the refractive power of the surface on the image side is almost zero, which is thinner than the thickness of the boundary lens provided in the immersion type projection optical system. Have Next, in step S303, the boundary lens included in the immersion type projection optical system is replaced with the replacement boundary lens prepared in the replacement boundary lens preparation step.

  As described above, in the projection optical system manufacturing methods according to the fifth and sixth embodiments, the simplest method of adjusting the thicknesses of the first optical element and the second optical element is used to bring the projection surface to the second surface side most. It is possible to maintain substantially the same optical characteristics as before the optical characteristics after interposing a medium having a refractive index of 1.1 or more in the optical path between the second optical element to be arranged and the second surface. . In addition, when the second optical element formed of the second glass material is disposed at a position where the energy of the exposure light is concentrated, the optical element is damaged by strong energy and the optical characteristics of the manufactured projection optical system are deteriorated. Can be prevented.

  In the projection optical system manufacturing methods according to the fifth and sixth embodiments, the thickness of the first optical element is increased and the thickness of the second optical element is decreased (the second optical element is exposed). A simple method of retreating from the optical path of light and setting the thickness of the second optical element to 0) in the optical path between the second optical element and the second surface. The optical characteristics after the medium is interposed can be maintained almost the same as the optical characteristics before the medium is interposed.

  In the projection optical system manufacturing methods according to the fifth and sixth embodiments, the flat plate is inserted in the insertion step, and the thickness adjustment step is performed to reduce the thickness of the boundary lens, thereby adjusting the distance. The optical characteristics before and after exchanging the liquid intervened in the optical path between the boundary lens and the second surface with gas are maintained substantially the same by adjusting the distance between the plane plate and the boundary lens in the process. can do.

  Next, a seventh embodiment of the present invention will be described with reference to the drawings. FIG. 24 is a view showing the schematic arrangement of a step-and-scan projection exposure apparatus according to the seventh embodiment of the present invention. In the following description, the XYZ orthogonal coordinate system shown in FIG. 24 is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the wafer W, and the Z axis is set in a direction orthogonal to the wafer W. In the XYZ coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z-axis is set vertically upward.

  As shown in FIG. 24, the projection exposure apparatus according to the seventh embodiment includes a KrF excimer laser light source as an exposure light source, and includes an optical integrator (homogenizer), a field stop, a condenser lens, and the like. An optical system 1 is provided. Exposure light (exposure beam) IL made up of ultraviolet pulsed light having a wavelength of 248 nm emitted from a light source passes through the illumination optical system 1 and illuminates a pattern provided on the reticle (mask) R. The light that has passed through the reticle R is the projection optical system PL1 according to the second embodiment, the projection optical system PL2 according to the third embodiment, the projection optical system PL3 according to the fourth embodiment, and the fifth. Via the projection optical system PL constructed by the projection optical system produced by the projection optical system production method according to the embodiment or the projection optical system produced by the projection optical system production method according to the sixth embodiment. Thus, reduced projection exposure is performed on the exposure area on the wafer W coated with the photoresist at a predetermined projection magnification β (for example, β is 1/4, 1/5, etc.).

  The reticle R is held on the reticle stage RST, and a mechanism for finely moving the reticle R in the X direction, the Y direction, and the rotation direction is incorporated in the reticle stage RST. In reticle stage RST, positions in the X direction, Y direction, and rotation direction are measured and controlled in real time by a reticle laser interferometer (not shown).

  The wafer W is fixed on the Z stage 9 via a wafer holder (not shown). The Z stage 9 is fixed on an XY stage 10 that moves along an XY plane substantially parallel to the image plane of the projection optical system PL, and the focus position (Z direction position) and tilt of the wafer W are tilted. Control the corners. In the Z stage 9, the positions in the X direction, the Y direction, and the rotation direction are measured and controlled in real time by a wafer laser interferometer 13 using a moving mirror 12 positioned on the Z stage 9. The XY stage 10 is placed on the base 11 and controls the X direction, Y direction, and rotation direction of the wafer W.

  The main control system 14 provided in the projection exposure apparatus adjusts the position of the reticle R in the X direction, the Y direction, and the rotational direction based on the measurement values measured by the reticle laser interferometer. That is, the main control system 14 adjusts the position of the reticle R by transmitting a control signal to a mechanism incorporated in the reticle stage RST and finely moving the reticle stage RST.

  Also, the main control system 14 adjusts the focus position (position in the Z direction) and the tilt angle of the wafer W in order to adjust the surface on the wafer W to the image plane of the projection optical system PL by the auto focus method and the auto leveling method. To do. That is, the main control system 14 transmits a control signal to the wafer stage drive system 15 and drives the Z stage 9 by the wafer stage drive system 15 to adjust the focus position and the tilt angle of the wafer W. Further, the main control system 14 adjusts the position of the wafer W in the X direction, the Y direction, and the rotation direction based on the measurement values measured by the wafer laser interferometer 13. That is, the main control system 14 transmits a control signal to the wafer stage drive system 15 and drives the XY stage 10 by the wafer stage drive system 15 to adjust the position of the wafer W in the X direction, Y direction, and rotation direction. .

  At the time of exposure, the main control system 14 transmits a control signal to a mechanism incorporated in the reticle stage RST, and also transmits a control signal to the wafer stage drive system 15, and a speed ratio corresponding to the projection magnification of the projection optical system PL. Then, the reticle stage RST and the XY stage 10 are driven to project and expose the pattern image of the reticle R into a predetermined shot area on the wafer W. Thereafter, the main control system 14 transmits a control signal to the wafer stage drive system 15 and drives the XY stage 10 by the wafer stage drive system 15 to step-shift another shot area on the wafer W to the exposure position. In this way, the operation of scanning and exposing the pattern image of the reticle R on the wafer W by the step-and-scan method is repeated.

  This projection exposure apparatus is configured to be replaceable with an immersion type exposure apparatus in order to substantially shorten the exposure wavelength and improve the resolution. Here, when the immersion type exposure apparatus is replaced, as shown in FIG. 24, a predetermined medium 7 is filled between the surface of the wafer W and the projection optical system PL, and synthetic quartz or fluorite is used. The optical elements constituting the projection optical system PL including the lens barrel 3 that houses the plurality of optical elements formed by the above are adjusted. In other words, the dry projection optical system PL is adjusted to the immersion type projection optical system PL. Here, in the adjustment of the optical elements constituting the projection optical system PL, the projection optical system according to the first to fourth embodiments described above or the manufacturing method of the projection optical system according to the fourth and sixth embodiments. The same adjustment as the adjustment of the thickness and the like of the optical element constituting the projection optical system manufactured by the above is performed. In the projection optical system PL, the reticle R side surface of the optical element 4 located closest to the wafer W is configured to have a positive refractive power. As the liquid 7, pure water (deionized water) that can be easily obtained in large quantities at a semiconductor manufacturing factory or the like is used.

  According to the projection exposure apparatus according to the seventh embodiment, the projection optical system according to any one of the second to fourth embodiments or the projection optical system according to the fifth or sixth embodiment. Since the projection optical system manufactured by the manufacturing method is provided, if necessary, a dry exposure apparatus that interposes a gas between the projection optical system PL and the wafer W, and between the projection optical system PL and the wafer W are provided. It is possible to switch between an immersion type exposure apparatus in which a liquid is interposed between the two. Therefore, when switching to the immersion type projection optical system PL, the pattern image of the reticle R can be satisfactorily exposed on the wafer W with high resolution even if the pattern of the reticle R is fine. Further, when switching to the dry projection optical system PL, the pattern image of the reticle R can be satisfactorily exposed on the wafer W with high throughput. Further, even when exposure is performed with the medium 7 having a refractive index of 1.1 or more interposed between the optical element 4 arranged closest to the wafer W of the projection optical system PL and the wafer W, In this case, the optical characteristics and the optical characteristics in a state where a gas is interposed between the optical element 4 and the wafer W can be maintained substantially the same, and the pattern image of the reticle R is satisfactorily exposed on the wafer W. can do.

  In the seventh embodiment, pure water is used as the liquid. However, it is possible to use another medium having a refractive index larger than 1.1 with respect to the exposure light. In this case, it is preferable to use a liquid that is transparent to the exposure light, has a refractive index as high as possible, and is stable to the projection optical system PL and the photoresist applied to the surface of the wafer W.

  In the exposure apparatus of each of the above embodiments, the illumination device illuminates the reticle (mask) (illumination process), and exposes the transfer pattern formed on the mask using the projection optical system onto the photosensitive substrate (exposure process). Thus, a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. Hereinafter, referring to the flowchart of FIG. 31 for an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of this embodiment. I will explain.

  First, in step 401 of FIG. 31, a metal film is deposited on one lot of wafers. In the next step 402, a photoresist is applied on the metal film on the one lot of wafers. Thereafter, in step 403, using the exposure apparatus of the present embodiment, the pattern image on the mask is sequentially exposed and transferred to each shot area on the wafer of one lot via the projection optical system. Thereafter, in step 404, the photoresist on the one lot of wafers is developed, and in step 405, the resist pattern is etched on the one lot of wafers to form a pattern on the mask. Corresponding circuit patterns are formed in each shot area on each wafer.

  Thereafter, a device pattern such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer. According to the semiconductor device manufacturing method described above, a semiconductor device having an extremely fine circuit pattern can be obtained with high throughput. In steps 401 to 405, a metal is vapor-deposited on the wafer, a resist is applied on the metal film, and exposure, development, and etching processes are performed. Prior to these processes, on the wafer. It is needless to say that after forming a silicon oxide film, a resist may be applied on the silicon oxide film, and steps such as exposure, development, and etching may be performed.

  In the exposure apparatus of this embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Hereinafter, an example of the technique at this time will be described with reference to the flowchart of FIG. In FIG. 32, in the pattern forming process 501, a so-called photolithography process is performed in which the exposure pattern of this embodiment is used to transfer and expose a mask pattern onto a photosensitive substrate (such as a glass substrate coated with a resist). By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate is subjected to steps such as a developing step, an etching step, and a resist stripping step, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming step 502.

  Next, in the color filter forming step 502, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix or three of R, G, and B A color filter is formed by arranging a plurality of stripe filter sets in the horizontal scanning line direction. Then, after the color filter forming process 502, a cell assembly process 503 is performed. In the cell assembly step 503, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 501 and the color filter obtained in the color filter formation step 502. In the cell assembling step 503, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern forming step 501 and the color filter obtained in the color filter forming step 502, and a liquid crystal panel (liquid crystal cell ).

  Thereafter, in a module assembly step 504, components such as an electric circuit and a backlight for performing display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete the liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display element, a liquid crystal display element having an extremely fine circuit pattern can be obtained with high throughput.

  In the above-described embodiment, the present invention is applied to the projection optical system mounted on the exposure apparatus. However, the present invention is not limited to this, and the present invention is applied to other general imaging optical systems. The invention can also be applied. In the above-described embodiment, the KrF or ArF excimer laser light source is used. However, the present invention is not limited to this, and other appropriate light sources that supply light of a predetermined wavelength can also be used.

  In the above-described embodiment, the present invention is applied to a step-and-scan exposure apparatus that scan-exposes a mask pattern to each exposure region of the substrate while moving the mask and the substrate relative to the projection optical system. Has been applied. However, the present invention is not limited to this, and the mask pattern is collectively transferred to the substrate while the mask and the substrate are stationary, and the mask pattern is sequentially exposed to each exposure region by sequentially moving the substrate stepwise. The present invention can also be applied to an exposure apparatus of an & repeat type.

  Since the lens configuration of the projection optical system according to Example 1 is the same as the lens configuration of the projection optical system PL1 according to the second embodiment shown in FIG. 14, the description of the projection optical system according to Example 1 will be made. The reference numerals used in the description of the projection optical system PL1 according to the second embodiment are used.

  The value of the item of projection optical system PL1 concerning Example 1 is shown. In this specification, NA indicates the numerical aperture. Further, in these specifications, the refractive indexes of quartz glass, fluorite and pure water indicate relative refractive indexes with respect to the atmosphere in the projection optical system PL1. Table 3 shows the optical member specifications of the dry projection optical system PL1 in which a gas is interposed between the plane parallel plate L24 and the wafer W1. In the optical member specifications of Table 3, the surface number of the first column is the order of the surfaces along the direction of ray travel from the object side, the second column is the radius of curvature (mm) of each surface, and the third column is each surface. The on-axis interval, that is, the surface interval (mm), and the fourth column indicates the glass material of the optical member.

  Table 4 shows the aspheric coefficients of lenses having an aspheric lens surface used in the projection optical system PL1 according to Example 1. In the aspheric coefficient in Table 4, the aspheric number in the first column corresponds to the surface number in the optical member specifications in Table 3. The second column is the curvature of each aspheric surface (1 / mm), the third column is the conic coefficient K and the aspherical coefficient of the 12th order E, the fourth column is the aspherical coefficient of the fourth order A and the 14th order F, the fifth column Is the 6th order B and 16th order aspherical coefficients, the sixth column is the 8th order C and 18th order aspherical coefficients, and the seventh column is the 10th order D and 20th order aspherical coefficients.

  In the first embodiment, the aspherical surface has the height in the direction perpendicular to the optical axis AX1 as y, and the light of the projection optical system PL1 from the tangential plane at the apex of the aspherical surface to the position on the aspherical surface at the height y. When the distance (sag amount) along the axis is z, the apex radius of curvature is r, the conic coefficient is K, and the m-th aspherical coefficient is Cm, it is expressed by the following formula (b).

z = (y ² / r) / [1+ {1- (1 + K) · y ² / r ² } ^1/2 ]
+ A · y ⁴ + B · y ⁶ + C · y ⁸ + D · y ¹⁰ + E · y ¹² + F · y ¹⁴
+ G · y ¹⁶ + H · y ¹⁸ + J · y ²⁰ (b)

(Specifications)
Image side NA: 0.8
Magnification: 1/4
Exposure area: Maximum image height 13.7 mm
Center wavelength: 248.4 nm
Quartz glass refractive index: 1.50839
Fluorite refractive index: 1.46788
Pure water refractive index: 1.396

  FIG. 25 is a transverse aberration diagram showing transverse aberration in the meridional direction and sagittal direction of the dry projection optical system PL1. In FIG. 25, Y represents the image height, and the solid line represents the lateral aberration at a wavelength of 248.4000 nm. As shown in the lateral aberration diagram of FIG. 25, in the dry projection optical system PL1, the aberration is corrected with a good balance.

  On the other hand, the plane-parallel plate L24 is retracted, the distance between the image-side surface of the positive meniscus lens L22 and the object-side surface of the plane-parallel plate L23, and the thickness of the plane-parallel plate L23 are changed. Table 5 shows the optical member specifications of the immersion type projection optical system PL1 in which pure water is interposed. In addition, about surface number 1-44, since it is the same as the optical member specification of surface number 1-44 shown in Table 3, display is abbreviate | omitted.

  FIG. 26 is a transverse aberration diagram showing transverse aberration in the meridional direction and sagittal direction of the immersion type projection optical system PL1. In FIG. 26, Y represents the image height, and the solid line represents the lateral aberration at a wavelength of 248.4000 nm. As shown in the lateral aberration diagram of FIG. 26, in the immersion type projection optical system PL1, the aberration is corrected with a good balance.

  According to the first embodiment, the plane parallel plate L24 is retracted, and the distance between the image side surface of the positive meniscus lens L22 and the object side surface of the plane parallel plate L23 and the thickness of the plane parallel plate L23 are changed. The optical characteristics of the dry projection optical system PL1 and the optical characteristics of the immersion projection optical system PL1 are maintained substantially the same.

  Since the lens configuration of the projection optical system according to Example 2 is the same as the lens configuration of the projection optical system PL2 according to the third embodiment shown in FIG. 16, the description of the projection optical system according to Example 2 will be omitted. The reference numerals used in the description of the projection optical system PL2 according to the third embodiment are used.

  The item of projection optical system PL2 concerning Example 2 is shown. In this specification, NA indicates the numerical aperture. Further, in these specifications, the refractive indexes of quartz glass, fluorite, and pure water indicate relative refractive indexes with respect to the atmosphere in the projection optical system PL2. Table 6 shows the optical member specifications of the projection optical system PL2 according to Example 2. Table 7 shows aspheric coefficients of lenses having an aspheric lens surface used in the projection optical system PL2 according to Example 2. The definition of each column of the optical member specifications shown in Table 6 and the definition of the aspherical coefficient shown in Table 7 are the same as those in Tables 3 and 4 according to Example 1, and therefore the projection optical system PL1 according to Example 1 The description will be made using the same reference numerals as used in the description.

(Specifications)
Image side NA: 0.8
Magnification: 1/4
Exposure area: Maximum image height 21.1mm
Center wavelength: 248.4 nm
Quartz glass refractive index: 1.50839
Fluorite refractive index: 1.46788
Pure water refractive index: 1.396

  FIG. 27 is a transverse aberration diagram showing transverse aberration in the tangential direction and sagittal direction of the dry projection optical system PL2. In FIG. 27, Y represents the image height, and the solid line represents the lateral aberration at a wavelength of 248.4000 nm. As shown in FIG. 27, in the projection optical system PL2, the aberration is corrected with a good balance.

  On the other hand, the optical member specifications of the immersion type projection optical system PL2 in which the thickness of the plane parallel plate L56 and the thickness of the plane parallel plate L57 are changed and water is interposed between the plane parallel plate L57 and the wafer W2. Is shown in Table 8. Since surface numbers 1 to 51 are the same as the optical member specifications of surface numbers 1 to 51 shown in Table 6, the display is omitted.

  FIG. 28 is a lateral aberration diagram showing lateral aberration in the tangential direction and sagittal direction of the immersion type projection optical system PL2. In FIG. 28, Y represents the image height, and the solid line represents the lateral aberration at a wavelength of 248.4000 nm. As shown in the lateral aberration diagram of FIG. 28, in the immersion type projection optical system PL2, the aberration is corrected with a good balance.

  According to the second embodiment, by changing the thickness of the plane parallel plate L56 and the thickness of the plane parallel plate L57, the optical characteristics of the dry projection optical system PL2 and the optical characteristics of the immersion projection optical system PL2 are changed. Are kept approximately the same.

  Since the lens configuration of the projection optical system according to Example 3 is the same as the lens configuration of the projection optical system PL3 according to the fourth embodiment shown in FIG. 18, the description of the projection optical system according to Example 3 will be omitted. The symbols used in the description of the projection optical system PL3 according to the fourth embodiment are used.

  The value of the item of projection optical system PL3 concerning Example 3 is shown. In this specification, NA indicates the numerical aperture. In these specifications, the refractive indexes of quartz glass, fluorite, and pure water indicate relative refractive indexes with respect to the atmosphere in the projection optical system PL3. Table 9 shows the optical member specifications of the projection optical system PL3 according to Example 3. Table 10 shows aspheric coefficients of lenses having an aspheric lens surface used in the projection optical system PL3 according to Example 3. The definition of each column of the optical member specifications shown in Table 9 and the definition of the aspherical coefficient shown in Table 10 are the same as those in Tables 3 and 4 according to Example 1, and therefore the projection optical system PL1 according to Example 1 The description will be made using the same reference numerals as those used in the description.

(Specifications)
Image side NA: 0.8
Magnification: 1/4
Exposure area: Maximum image height 21.1mm
Center wavelength: 248.4 nm
Quartz glass refractive index: 1.50839
Fluorite refractive index: 1.46788
Pure water refractive index: 1.396

  FIG. 29 is a transverse aberration diagram showing transverse aberration in the tangential direction and sagittal direction of the dry projection optical system PL3 in which a gas is interposed between the plane parallel plate L86 and the wafer W3. In FIG. 29, Y represents the image height, and the solid line represents the lateral aberration at a wavelength of 248.4000 nm. As shown in FIG. 29, the dry projection optical system PL3 has aberrations corrected in a well-balanced manner.

  On the other hand, Table 11 shows the optical member specifications of the immersion type projection optical system PL3 in which the plane parallel plate L86 is replaced with the plane parallel plate L86 ′ and water is interposed between the plane parallel plate L86 ′ and the wafer W3. Show. In addition, about surface number 1-50, since it is the same as the optical member specification of surface number 1-50 shown in Table 9, display is abbreviate | omitted.

  FIG. 30 is a transverse aberration diagram showing transverse aberration in the tangential and sagittal directions of the immersion type projection optical system PL3. In FIG. 30, Y represents the image height, and the solid line represents the lateral aberration at a wavelength of 248.4000 nm. As shown in FIG. 30, in the immersion type projection optical system PL3, aberrations are corrected with a good balance.

  According to the third embodiment, by replacing the plane parallel plate L86 with the plane parallel plate L86 ′, the optical characteristics of the dry projection optical system PL3 and the optical characteristics of the immersion projection optical system PL3 are substantially the same. Maintained.

Explanation of symbols

100 Laser light source IL Illumination optical system R Reticle RS Reticle stage PL Projection optical system W Wafer WS Wafer stage Li Lens component Pi Parallel plane plate AS Aperture stop

Claims (57)

In an immersion type imaging optical system having an immersion layer in contact with the image plane,
A first medium layer composed of a first medium, in order from the immersion layer side, between the optical surface having a predetermined refractive power disposed closest to the image surface and the immersion layer, and the first medium A second medium layer made of a second medium having a refractive index different from that of the first medium and a third medium layer made of a third medium having a refractive index different from that of the first medium and the second medium,
The boundary surface between the immersion layer and the first medium layer, the boundary surface between the first medium layer and the second medium layer, and the boundary surface between the second medium layer and the third medium layer are respectively flat. An imaging optical system characterized by being formed in a shape. The imaging optical system according to claim 1, wherein the first medium and the third medium are solid, and the second medium is a gas. 3. The connection according to claim 1, wherein one of the first medium and the third medium is quartz, and the other of the first medium and the third medium is fluorite. Image optics. An imaging optical system having four medium layers having different refractive indexes between an optical surface having a predetermined refractive power disposed closest to the image surface and the image surface,
The radius of curvature of the boundary surface between two arbitrary medium layers adjacent to each other among the four medium layers is R, the maximum image height of the imaging optical system is Ym, and the optical surface having the predetermined refractive power When the radius of curvature is Rp,
Ym / | R | <0.01
Ym / | Rp |> 0.003
An imaging optical system characterized by satisfying the following conditions. An imaging optical system having at least three medium layers having different refractive indexes between a lens disposed closest to an image plane or an object plane and the image plane or the object plane,
The at least three medium layers each have no refractive power;
An imaging optical system, wherein all boundary surfaces of the at least three medium layers are formed in a planar shape. 6. The imaging optical system according to claim 1, wherein a refractive index difference between two arbitrary media having different refractive indexes is 0.01 or more. The imaging optical system according to claim 1, wherein the imaging optical system is substantially telecentric on the image plane side. An aberration adjustment method for an imaging optical system according to any one of claims 1 to 3,
By changing the thickness along the optical axis of the first medium layer, the thickness along the optical axis of the second medium layer, and the thickness along the optical axis of the third medium layer, respectively, An aberration adjustment method, comprising: correcting a spherical aberration generated in the imaging optical system due to a change in a refractive index of a medium between the imaging optical system and the image plane. An aberration adjustment method for an imaging optical system according to claim 4,
An aberration adjustment method, wherein the spherical aberration of the imaging optical system is corrected by changing the thickness along the optical axis in at least three of the four medium layers. An aberration adjusting method for an imaging optical system according to claim 5,
An aberration adjustment method comprising correcting the spherical aberration of the imaging optical system by changing at least one of a thickness and a refractive index along the optical axis in each of the at least three medium layers. The aberration adjustment method according to any one of claims 8 to 10, wherein a difference in refractive index between two arbitrary media having different refractive indexes is 0.01 or more. 12. The aberration adjustment method according to claim 8, wherein the imaging optical system is substantially telecentric on the image plane side. In a method for adjusting an imaging optical system for forming an image of an object,
An image-side medium changing step of changing the medium of the image-side medium layer, which is a medium layer between the most image-side optical surface on the most image side of the imaging optical system and the image plane, between gas and liquid;
A thickness along the optical axis of a first medium layer formed between the optical surface having a predetermined refractive power disposed closest to the image surface and the image-side medium layer, and the optical surface; A thickness along the optical axis of a second medium layer made of a second medium disposed between the surface and the first medium layer and having a refractive index different from that of the first medium layer, and the optical surface and the first medium layer. The medium in the image side space is changed by changing the thickness along the optical axis of the third medium layer disposed between the two medium layers and having a refractive index different from that of the first medium and the second medium. And an aberration correction step of correcting spherical aberration generated in the imaging optical system due to the above. The imaging optical system adjustment method according to claim 13, wherein the first medium and the third medium are solid, and the second medium is a gas. The result according to claim 13 or 14, wherein one of the first medium and the third medium is quartz, and the other of the first medium and the third medium is fluorite. Image optical system adjustment method. The boundary surface between the image side medium layer and the first medium layer, the boundary surface between the first medium layer and the second medium layer, and the boundary surface between the second medium layer and the third medium layer are respectively The imaging optical system adjustment method according to claim 13, wherein the imaging optical system is formed in a planar shape. In a method for adjusting an imaging optical system for forming an image of an object,
An image-side medium changing step of changing the medium of the image-side medium layer, which is a medium layer between the most image-side optical surface on the most image side of the imaging optical system and the image plane, between gas and liquid;
A first medium layer comprising a first medium disposed between the optical surface having a predetermined refractive power disposed closest to the image plane and the image-side medium layer; and the optical surface and the first medium layer. A second medium layer made of a second medium having a refractive index different from that of the first medium layer, and the first medium disposed between the optical surface and the second medium layer. And by changing at least one of the thickness and refractive index along the optical axis of the third medium layer having a refractive index different from that of the second medium to change the medium in the image side space. And an aberration correction step of correcting spherical aberration generated in the imaging optical system,
R is a radius of curvature of a boundary surface between two adjacent medium layers among the image side medium layer, the first medium layer, the second medium layer, and the third medium layer, and the imaging optics When the maximum image height of the system is Ym and the radius of curvature of the optical surface having the predetermined refractive power is Rp,
Ym / | R | <0.01
Ym / | Rp |> 0.003
An imaging optical system adjusting method characterized by satisfying the following conditions: 18. The imaging optical system adjustment method according to claim 13, wherein a refractive index difference between two arbitrary media having different refractive indexes is 0.01 or more. The method of adjusting an imaging optical system according to claim 13, wherein the imaging optical system is substantially telecentric on the image plane side. The illumination system for illuminating the mask, and the result of any one of claims 1 to 7 for forming an image of a pattern formed on the mask on a photosensitive substrate set on the image plane. An exposure apparatus comprising an image optical system. The projection optical system for projecting and exposing the mask pattern onto the photosensitive substrate includes an imaging optical system that is aberration-adjusted by the aberration adjustment method according to any one of claims 8 to 12. An exposure apparatus. An imaging optical system adjusted by the adjustment method according to any one of claims 13 to 19 is provided as a projection optical system for projecting and exposing a mask pattern onto a photosensitive substrate. Exposure device. The exposure apparatus according to any one of claims 20 to 22, wherein the imaging optical system is an immersion type optical system having an immersion layer in contact with the image plane. The mask is illuminated, and the pattern formed on the mask is projected and exposed onto the photosensitive substrate set on the image plane via the imaging optical system according to any one of claims 1 to 7. A featured exposure method. A projection image of a pattern image formed on a mask is projected and exposed on a photosensitive substrate using the imaging optical system in which the aberration is adjusted by the aberration adjustment method according to any one of claims 8 to 12. Exposure method. 20. An exposure comprising: projecting and exposing a pattern image formed on a mask onto a photosensitive substrate using the imaging optical system adjusted by the adjustment method according to any one of claims 13 to 19. Method. A liquid configured to be attached to a dry imaging optical system that forms an image of an object through a gas, and for changing the image of the object to an immersion imaging optical system that forms through a liquid An optical unit for changing immersion,
Among the optical surfaces having the refractive power in the dry-type imaging optical system, the optical surface is provided so as to be exchangeable with an optical member disposed on the image side of the optical surface having the predetermined refractive power disposed on the most image side. A first optical member formed of a first medium having a predetermined refractive index;
A second optical member provided in a replaceable manner with the optical member in the dry imaging optical system and formed of a second medium having a refractive index different from that of the first optical member;
At least one of the thickness along the optical axis of the first optical member and the refractive index of the first medium, and the thickness along the optical axis of the second optical member and the refractive index of the second medium. At least one of them is defined so as to correct spherical aberration generated due to the change of the type of the medium on the image side of the imaging optical system from gas to liquid. Optical unit. 28. The optical unit according to claim 27, wherein one of the first optical member and the second optical member is made of quartz, and the other is made of fluorite. The optical unit according to claim 27 or 28, wherein a difference in refractive index between the first medium and the second medium is 0.01 or more. A liquid configured to be attached to a dry imaging optical system that forms an image of an object through a gas, and for changing the image of the object to an immersion imaging optical system that forms through a liquid An optical unit for changing immersion,
Among the optical surfaces having the refractive power in the dry-type imaging optical system, the optical surface is provided so as to be exchangeable with an optical member disposed on the image side of the optical surface having the predetermined refractive power disposed on the most image side. A first optical member formed of a first medium having a predetermined refractive index;
A second optical member provided in a replaceable manner with the optical member in the dry imaging optical system and formed of a second medium having a refractive index different from that of the first optical member;
An optical surface having the predetermined refractive power, where R is the radius of curvature of the two optical surfaces of the first optical member and the two optical surfaces of the second optical member, and Ym is the maximum image height of the imaging optical system. When the radius of curvature of Rp is Rp,
Ym / | R | <0.01
Ym / | Rp |> 0.003
An optical unit that satisfies the following conditions. The first optical member is disposed on the image side of the second optical member,
The thickness along the optical axis of the first optical member, the thickness along the optical axis of the second optical member, the distance between the first optical member and the second optical member, and the first optical member At least three of the intervals with the image are determined so as to correct spherical aberration caused by changing the type of the medium on the image side of the imaging optical system from gas to liquid. The optical unit according to claim 30, wherein An immersion-changing optical unit for changing a dry-type imaging optical system that forms an image of an object through a gas into an immersion-type imaging optical system that forms an image of the object through a liquid Because
At least one exchangeable with an optical member disposed on the image side of the optical surface having a predetermined refractive power disposed on the most image side of the optical surfaces having a refractive power in the dry imaging optical system. An optical member,
This is because the type of medium on the image side of the imaging optical system is changed from gas to liquid by replacing the optical member in the dry imaging optical system with the at least one optical member. An optical unit that reduces degradation of imaging characteristics of the imaging optical system that occurs when The optical unit according to claim 32, wherein the imaging characteristics of the imaging optical system include spherical aberration. 34. The optical unit according to claim 32 or 33, wherein the at least one optical member includes a plane-parallel plate. 35. The optical unit according to claim 32, wherein the at least one optical member includes at least two optical members having different refractive indexes. The refractive index of the optical member having the optical surface having the predetermined refractive power arranged on the most image side among the optical surfaces having the refractive power in the dry imaging optical system, and the at least one optical member 36. The optical unit according to any one of claims 32 to 35, wherein the refractive indexes of the optical units differ from each other. The optical member disposed on the image side of the optical surface having a predetermined refractive power, which is disposed closest to the image side among the optical surfaces having refractive power in the dry imaging optical system, is a parallel plane plate. 37. The optical unit according to claim 32, comprising an optical unit. In a projection optical system comprising a plurality of optical elements and forming an image of a first surface on a second surface using exposure light having a wavelength of 200 nm to 300 nm,
A first optical element disposed in the vicinity of the second surface and having a refractive power of approximately 0 on the second surface side;
A second optical element that is disposed closest to the second surface side and has a refractive power of approximately 0,
More than 80% of the plurality of optical elements are formed of the first glass material,
One of the first optical element and the second optical element is formed of the first glass material,
The other of the first optical element and the second optical element is formed of a second glass material having a lower refractive index than the first glass material,
A projection optical system characterized in that the second surface side is telecentric. The projection optical system according to claim 38, wherein the first optical element is a lens or a plane parallel plate. 40. The projection optical system according to claim 38, wherein the second optical element is formed of the second glass material. In order to maintain substantially the same optical characteristics as before the optical characteristics after interposing a medium having a refractive index of 1.1 or more in the optical path between the second optical element and the second surface, 41. The projection optical system according to claim 38, wherein the thickness of the first optical element is increased and the thickness of the second optical element is decreased. The reduction in the thickness of the second optical element includes making the thickness of the second optical element zero by retracting the second optical element from the optical path of the exposure light. 42. The projection optical system according to 41. In a projection optical system comprising a plurality of optical elements and forming an image of a first surface on a second surface using exposure light having a wavelength of 200 nm to 300 nm,
A boundary lens disposed in the vicinity of the second surface and having a refractive power of approximately 0 on the second surface side;
A flat plate inserted in the vicinity of the second surface,
All of the plurality of optical elements excluding the plane plate are formed of the first glass material,
The flat plate is formed of a second glass material having a lower refractive index than the first glass material,
When the liquid interposed in the optical path between the boundary lens and the second surface is exchanged for gas, by adjusting the thickness of the boundary lens and the distance between the boundary lens and the plane plate, Maintaining substantially the same optical properties before and after the exchange of the liquid and the gas,
A projection optical system characterized in that the second surface side is telecentric. In a projection optical system comprising a plurality of optical elements and forming an image of a first surface on a second surface using exposure light having a wavelength of 200 nm to 300 nm,
More than 80% of the plurality of optical elements are formed of the first glass material,
At least one optical element that is disposed in the vicinity of the second surface and is formed of a second glass material having a refractive index lower than that of the first glass material and has a refractive power of approximately 0 on the second surface side;
A projection optical system characterized in that the second surface side is telecentric. 45. The projection optical system according to claim 38, wherein the first glass material is synthetic quartz and the second glass material is fluorite. Production of a projection optical system comprising a plurality of optical elements, using exposure light having a wavelength of 200 nm to 300 nm, and forming an image of the first surface on the second surface under a telecentric light beam on the second surface side In the method
An optical element forming step of forming 80% or more of the plurality of optical elements with the first glass material;
A first optical element preparation step of preparing a first optical element that is formed of the first glass material and has a refractive power of about 0 on the second surface side;
A second optical element preparation step of preparing a second optical element formed of a second glass material having a refractive index lower than that of the first glass material and having a refractive power of approximately 0;
A first thickness adjusting step of adjusting the thickness of the first optical element disposed in the vicinity of the second surface;
A second thickness adjusting step for adjusting the thickness of the second optical element that is arranged closest to the second surface side,
In the first thickness adjusting step and the second thickness adjusting step, optical characteristics after a medium having a refractive index of 1.1 or more is interposed in the optical path between the second optical element and the second surface. A method of manufacturing a projection optical system, comprising adjusting the thicknesses of the first optical element and the second optical element so as to maintain substantially the same optical characteristics as before the interposition. The thickness of the first optical element is increased in the first thickness adjusting step, and the thickness of the second optical element is decreased in the second thickness adjusting step. Projection optical system manufacturing method. The second thickness adjusting step further includes a retracting step of reducing the thickness of the second optical element to 0 by retracting the second optical element from the optical path of the exposure light. Item 48. A method for manufacturing a projection optical system according to Item 46 or 47. Production of a projection optical system comprising a plurality of optical elements, using exposure light having a wavelength of 200 nm to 300 nm, and forming an image of the first surface on the second surface under a telecentric light beam on the second surface side In the method
An optical element preparation step of preparing a flat plate formed of a second glass material having a lower refractive index than the first glass material;
An insertion step of inserting the flat plate in the vicinity of the second surface;
A thickness adjusting step of adjusting a thickness of a boundary lens that is arranged closest to the second surface side and is formed of the first glass material and has a refractive power of approximately 0 on the second surface side;
An interval adjusting step of adjusting an interval between the planar plate inserted in the inserting step and the boundary lens,
The boundary plate is inserted in the insertion step, the thickness of the boundary lens is adjusted in the thickness adjustment step, and the interval between the plane plate and the boundary lens is adjusted in the interval adjustment step. Maintaining substantially the same optical characteristics before and after exchanging the liquid interposed in the optical path between the lens and the second surface with gas,
A method for manufacturing a projection optical system, wherein all of the plurality of optical elements excluding the flat plate are formed of a first glass material. The optical element preparation step is an exchange for preparing a replacement boundary lens that is thinner than the boundary lens and that is formed of the first glass material and has a refractive power of approximately 0 on the second surface side. Further including a boundary lens preparation step,
50. The projection optical system according to claim 49, wherein the thickness adjusting step further includes a replacement step of replacing the boundary lens with the replacement boundary lens prepared in the replacement boundary lens preparation step. Production method. 51. The method of manufacturing a projection optical system according to claim 46, wherein the first glass material is synthetic quartz and the second glass material is fluorite. In an exposure apparatus that transfers a mask pattern onto a photosensitive substrate,
An illumination optical system for illuminating the mask;
A projection optical system according to any one of claims 38 to 45 for forming an image of the mask pattern on the photosensitive substrate,
An exposure apparatus comprising: In an exposure apparatus that transfers a mask pattern onto a photosensitive substrate,
An illumination optical system for illuminating the mask;
A projection optical system produced by the projection optical system production method according to any one of claims 46 to 51 for forming an image of the mask pattern on the photosensitive substrate,
An exposure apparatus comprising: An image of the mask pattern is formed on the photosensitive substrate with a medium having a refractive index of 1.1 or more interposed between the surface of the projection optical system closest to the photosensitive substrate and the photosensitive substrate. 54. The exposure apparatus according to claim 52 or 53, wherein the exposure apparatus is formed. In an exposure method for transferring a predetermined pattern onto a photosensitive substrate,
Illuminating a mask on which the predetermined pattern is formed; and
46. An exposure method comprising: a projection step of projecting using the projection optical system according to any one of claims 38 to 45 for forming an image of the predetermined pattern on the photosensitive substrate. . In an exposure method for transferring a predetermined pattern onto a photosensitive substrate,
Illuminating a mask on which the predetermined pattern is formed; and
52. A projection step of projecting using the projection optical system manufactured by the method of manufacturing a projection optical system according to claim 46, for forming an image of the predetermined pattern on the photosensitive substrate. An exposure method comprising: In the projection step, the image of the pattern of the mask is exposed to the photosensitive substrate with a medium having a refractive index of 1.1 or more interposed between the surface closest to the photosensitive substrate of the projection optical system and the photosensitive substrate. The exposure method according to claim 55 or 56, wherein the exposure method is formed on a conductive substrate.

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