JP2005257740A - Projection optical system, exposing device, and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a relatively small-sized projection optical system applicable to a stitching exposure device, an exposure device, and an exposure method. <P>SOLUTION: The projection optical system for forming a reduction image of a first surface (R) on a second surface (W) satisfies condition 6.6<ϕmax/ϕo<12 wherein ϕo is a maximum object height in the first surface and ϕmax is a value of a maximum effective diameter out of effective diameters of all lenses in the projection optical system. The projection optical system has projection magnifications from about ¾1/5¾ to about ¾1/4¾ and forms an reduction image of the first surface on the second surface in such a state that an optical path between the projection optical system and the second surface is filled with a medium having ≥1.1 refractive index when a refractive index of an atmosphere in the optical path of the projection optical system is 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  In a photolithography process for manufacturing a semiconductor element or the like, a pattern image of a mask (or reticle) is exposed on a photosensitive substrate (a wafer or a glass plate coated with a photoresist or the like) via a projection optical system. An exposure apparatus is used. As this type of exposure apparatus, for example, Japanese Patent Publication No. 46-34057 discloses an exposure apparatus of a slit scanning type (hereinafter simply referred to as “stitching type”) in a stitching method.

  In the stitching method exposure apparatus, the partial exposure region in the first row on the photosensitive substrate is obtained by synchronously moving the mask and the photosensitive substrate in the first direction with respect to the illumination region having a predetermined shape on the mask. The first scan exposure (scan exposure) is performed. Thereafter, for example, the mask is moved by a predetermined amount in a second direction perpendicular to the first direction, and the photosensitive substrate is laterally shifted (stitched) in a direction conjugate to the second direction.

  Then, the mask and the photosensitive substrate are moved relative to each other in a first direction synchronously with respect to the illumination area having a predetermined shape on the mask again, so that the second exposure to the partial exposure region in the second row on the photosensitive substrate is performed. Perform the second scan exposure. Thus, in the stitching type exposure apparatus, one shot area including the first column partial exposure region and the second column partial exposure region, that is, an image field (effective imaging region) of the projection optical system. The mask pattern is transferred to an area on a wide photosensitive substrate.

  As described above, in the stitching type exposure apparatus, for example, by performing scan exposure on two partial exposure regions without exchanging the mask, a mask pattern is formed on one shot region wider than the image field of the projection optical system. Can be transferred. As a result, the cost can be reduced by using a relatively small projection optical system, and the throughput can be improved by eliminating the need for mask replacement.

  However, in the prior art, no specific proposal has been made regarding the configuration of a projection optical system suitable for a stitching type exposure apparatus. As the degree of integration of semiconductor elements and the like increases, the resolution (resolution) required for the projection optical system of the exposure apparatus is increasing. Therefore, in the projection optical system of the exposure apparatus, it is necessary to shorten the wavelength of the illumination light (exposure light) and ensure a large image-side numerical aperture in order to satisfy the requirement for the resolution.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a relatively small projection optical system that can be applied to, for example, a stitching type exposure apparatus. It is another object of the present invention to provide an exposure apparatus and an exposure method that can perform, for example, stitching type exposure using a relatively small projection optical system.

In order to solve the above problems, in the first embodiment of the present invention, in the projection optical system for forming a reduced image of the first surface on the second surface,
When the maximum object height on the first surface is φo, and the maximum effective diameter value of all the effective diameters of the lenses in the projection optical system is φmax,
6.6 <φmax / φo <12
A projection optical system characterized by satisfying the above conditions is provided.

  According to a preferred aspect of the first aspect, the projection optical system has a projection magnification of about | 1/5 | to about | 1/4 |. When the refractive index of the atmosphere in the optical path of the projection optical system is 1, the optical path between the projection optical system and the second surface is filled with a medium having a refractive index greater than 1.1. Preferably, a reduced image of the first surface is formed on the second surface in a state.

  In the second embodiment of the present invention, an illumination process for illuminating the mask set on the first surface, and an image of a pattern formed on the mask via the projection optical system of the first embodiment is set on the second surface. And an exposure step of performing projection exposure on the photosensitive substrate.

  According to a preferred aspect of the second aspect, in the exposure step, projection exposure is performed on one shot region including two partial exposure regions, and the exposure step includes at least a partial exposure step of performing projection exposure on the partial exposure region. In the partial exposure step, scanning exposure to the partial exposure region is performed while relatively moving the mask and the photosensitive substrate with respect to the projection optical system.

  In this case, the exposure step includes a first partial exposure step of performing scanning exposure on one partial exposure region while relatively moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system. A second partial exposure step of performing scanning exposure on the other partial exposure region while relatively moving the mask and the photosensitive substrate in the direction opposite to the predetermined direction with respect to the projection optical system. It is preferable. Alternatively, the exposure step includes a first partial exposure step of performing scanning exposure on one partial exposure region while relatively moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system; It is preferable to include a second partial exposure step of performing scanning exposure on the other partial exposure region while relatively moving the mask and the photosensitive substrate in the predetermined direction with respect to the projection optical system.

  According to a preferred aspect of the second aspect, in the exposure step, projection exposure is performed on a plurality of shot regions, and the exposure step includes projection exposure on a predetermined partial exposure region in the plurality of shot regions. A first partial exposure step, and a second partial exposure step of performing projection exposure to another partial exposure region in the plurality of shot regions. Further, it is preferable that the mask is not exchanged between the first partial exposure process and the second partial exposure process. In the second embodiment, prior to the exposure step, when the refractive index of the atmosphere in the optical path of the projection optical system is 1, the optical path between the projection optical system and the photosensitive substrate is 1.1. The exposure method according to any one of claims 4 to 9, further comprising a filling step of filling with a medium having a larger refractive index.

  In the third aspect of the present invention, an illumination system for illuminating the mask set on the first surface and an image of a pattern formed on the mask are formed on the photosensitive substrate set on the second surface. An exposure apparatus is provided that includes the projection optical system according to the first embodiment.

  According to a preferred aspect of the third aspect, the photosensitive substrate is subjected to scanning exposure while moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system, and the mask is supported to support the mask. A mask stage for stepping in a direction substantially perpendicular to the predetermined direction is further provided.

  In the present invention, since a predetermined conditional expression relating to the maximum object height and the maximum effective diameter of the lens is satisfied, a relatively small projection optical system applicable to, for example, a stitching type exposure apparatus can be realized. . Therefore, in the exposure apparatus and the exposure method of the present invention, for example, a stitching type exposure can be performed using a relatively small projection optical system, and thus a good device can be manufactured.

The projection optical system of the present invention has a projection magnification of about 1/5 to about 1/4 (absolute value), for example, and satisfies the following conditional expression (1). In conditional expression (1), φo is the maximum object height on the object surface (first surface), and φmax is the value of the maximum effective diameter (diameter) of the effective diameters of all the lenses in the projection optical system. is there.
6.6 <φmax / φo <12 (1)

  If the lower limit value of conditional expression (1) is not reached, the numerical aperture on the object side is relatively large, so that the Petzval condition cannot be satisfied, and the flatness of the image is deteriorated. On the other hand, if the upper limit of conditional expression (1) is exceeded, the optical system will be enlarged in the radial direction. That is, by satisfying conditional expression (1), it is necessary to transfer the mask pattern to one predetermined size shot area by scanning exposure to two partial exposure areas without increasing the size of the projection optical system. An effective imaging area (image field) having a required size can be ensured.

  In order to achieve the effect of the present invention more satisfactorily, it is preferable to set the lower limit value of conditional expression (1) to 8 and the upper limit value to 11. Thus, according to the present invention, it is possible to realize a relatively small projection optical system applicable to, for example, a stitching type exposure apparatus. Therefore, the exposure apparatus and the exposure method of the present invention can perform, for example, stitching type exposure using a relatively small projection optical system.

  In the present invention, a medium having a refractive index larger than 1.1, for example, a medium having a high refractive index such as liquid (or fluid) is interposed in the optical path between the projection optical system and the photosensitive substrate. Is preferred. With this configuration, it is possible to increase the image-side numerical aperture of the projection optical system and to improve the resolution. In the exposure apparatus and exposure method of the present invention, it is possible to perform good projection exposure with high resolution using a high-resolution projection optical system having a large effective image-side numerical aperture.

  By the way, the resolution of the projection optical system is expressed by k · λ / NA (k is a process coefficient) where λ is the wavelength of illumination light (exposure light) and NA is the image-side numerical aperture of the projection optical system. The image-side numerical aperture NA of the projection optical system is such that the refractive index of a medium (usually a gas such as air) between the projection optical system and the photosensitive substrate is n, and the maximum incident angle to the photosensitive substrate is θ. , 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, conventionally, a technique for increasing the image-side numerical aperture NA 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 has been proposed. By the way, “Resolution Enhancement of 157-nm Lithography by Liquid Immersion” announced by M.Switkes and M.Rothschild at “Massachusetts Institute of Technology” at “SPIE2002 Microlithography” Examples of the medium having the required transmittance include Fluorinert (Perfluoropolyethers: a trade name of 3M USA) and Deionized Water.

Embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a drawing schematically showing a configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, 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. 1 in the plane perpendicular to the optical axis AX, and the X axis is perpendicular to the paper surface of FIG. Are set respectively. The illustrated exposure apparatus includes an ArF excimer laser light source as the light source 100 for supplying illumination light in the ultraviolet region.

  The light emitted from the light source 100 illuminates the reticle R on which a predetermined pattern is formed in a superimposed manner 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 the wafer holder table 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 region. 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 exposure apparatus of the present embodiment, the optical member (parallel plane plate P1 in each embodiment) arranged closest to the reticle among the optical members constituting the projection optical system PL and the boundary lens arranged closest to the wafer. The interior of the projection optical system PL is kept airtight with the Lb, and the gas inside the projection optical system PL is replaced with an inert gas such as helium gas or nitrogen, or is almost in a vacuum state. Is retained.

  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 an inert gas such as nitrogen or helium gas, or is kept in a vacuum state. 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.

  FIG. 2 is a diagram schematically showing a configuration from the boundary lens to the wafer in each embodiment. Referring to FIG. 2, in each embodiment, the optical path between the boundary lens Lb disposed on the most wafer side of the projection optical system PL and the wafer W is filled with a medium Lm having a refractive index greater than 1.1. Has been. In each embodiment, pure water is used as the medium Lm.

  In order to continue filling the liquid medium Lm in the optical path between the boundary lens Lb of the projection optical system PL and the wafer W, for example, the technique disclosed in International Publication No. WO99 / 49504 or Japanese Patent Laid-Open No. 10-303114 The technique disclosed in the publication number can be used. In the technique disclosed in International Publication No. WO99 / 49504, the liquid (medium Lm) adjusted to a predetermined temperature is supplied between the boundary lens Lb and the wafer W through the supply pipe and the discharge nozzle from the liquid supply device. The liquid is supplied so as to fill the optical path, and the liquid is recovered from the wafer W via the recovery pipe and the inflow nozzle by the liquid supply device.

  On the other hand, in the technique disclosed in Japanese Patent Application Laid-Open No. 10-303114, the wafer holder table WT is configured in a container shape so as to accommodate the liquid (medium Lm), and at the center of its inner bottom (in the liquid ) The wafer W is positioned and held by vacuum suction. Further, the lens barrel tip of the projection optical system PL reaches the liquid, and the optical surface on the wafer side of the boundary lens Lb reaches the liquid.

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

In each embodiment, the lens component constituting the projection optical system PL is made of quartz (SiO ₂ ) or fluorite (CaF ₂ ). Further, 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 is 1.5603261, and the refractive index of fluorite is 1.5014548. Further, as the medium Lm interposed between the boundary lens Lb and the wafer W, pure water having a refractive index of 1.436 with respect to the exposure light is used.

In each embodiment, the aspherical surface has a height in the direction perpendicular to the optical axis as y, and the distance along the optical axis from the tangential plane at the apex of the aspherical surface to the position on the aspherical surface at height y ( When the sag amount is z, the apex radius of curvature is r, the conic coefficient is κ, and the nth-order aspheric coefficient is C _n , the following equation (a) is obtained. In each embodiment, the 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)

[First embodiment]
FIG. 3 is a diagram showing a lens configuration of the projection optical system according to the first example of the present embodiment. Referring to FIG. 3, the projection optical system PL of the first embodiment includes, in order from the reticle side, a plane parallel plate P1, a biconcave lens L1 with an aspheric concave surface facing the wafer side, and an aspheric shape on the reticle side. Negative meniscus lens L2 with the concave surface facing the lens, positive meniscus lens L3 with the aspherical concave surface facing the reticle side, biconvex lens L4, biconvex lens L5, biconvex lens L6, and convex surface facing the reticle side A positive meniscus lens L7, a positive meniscus lens L8 having a convex surface facing the reticle, a negative meniscus lens L9 having an aspheric concave surface facing the wafer, a biconcave lens L10, and an aspheric concave surface facing the reticle. A biconcave lens L11 directed toward the wafer, a negative meniscus lens L12 having an aspherical concave surface facing the wafer side, and a biconcave lens L13 having an aspherical concave surface directed toward the wafer side A positive meniscus lens L14 having an aspherical concave surface facing the reticle side, a positive meniscus lens L15 having a concave surface facing the reticle side, a positive meniscus lens L16 having a concave surface facing the reticle side, and a concave surface facing the reticle side Positive meniscus lens L17, biconvex lens L18, positive meniscus lens L19 having a convex surface facing the reticle, positive meniscus lens L20 having an aspheric concave surface facing the wafer, and positive meniscus having a convex surface facing the reticle The lens L21 and a planoconvex lens L22 (boundary lens Lb) having an aspheric convex surface facing the reticle side.

  In the first example, the optical path between the plano-convex lens L22 as the boundary lens Lb and the wafer W is filled with a medium Lm made of pure water. The lenses L21 and L22 (Lb) are made of fluorite, and the other lens components are made of quartz.

  In the following table (1), values of specifications of the projection optical system PL according to the first example are listed. In Table (1), λ is the center wavelength of the exposure light, β is the projection magnification (imaging magnification), NA is the image side (wafer side) numerical aperture, φo is the maximum object height, and φi is the maximum image height. Respectively. Further, 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 aspheric surface), and d is the on-axis interval of each surface, that is, the surface interval (mm). N represents the refractive index with respect to the center wavelength. The notation in table (1) is the same in the following tables (2) and (3).

Table 1
(Main specifications)
λ = 193.306 nm
β = -1 / 4
NA = 1.2
φo = 28mm
φi = 7mm

(Optical member specifications)
Surface number r dn Optical member (reticle surface) 35.000
1 ∞ 4.242 1.5603261 (P1)
2 ∞ 3.103
3 -1120.724 14.000 1.5603261 (L1)
4 * 131.381 30.070
5 * -60.462 14.000 1.5603261 (L2)
6 -1144.786 10.490
7 * -181.346 47.368 1.5603261 (L3)
8 -104.187 1.000
9 943.990 38.188 1.5603261 (L4)
10 -496.595 1.000
11 628.344 55.762 1.5603261 (L5)
12 -443.823 1.000
13 396.894 43.046 1.5603261 (L6)
14 -4228.725 1.000
15 218.155 40.608 1.5603261 (L7)
16 456.639 1.000
17 135.351 43.275 1.5603261 (L8)
18 210.000 1.143
19 208.211 39.159 1.5603261 (L9)
20 * 193.457 20.707
21 -8222.387 14.000 1.5603261 (L10)
22 86.090 34.410
23 * -272.301 14.000 1.5603261 (L11)
24 113.482 12.131
25 318.395 14.000 1.5603261 (L12)
26 * 121.345 17.802
27 -1752.350 14.000 1.5603261 (L13)
28 * 431.697 24.701
29 * -785.410 37.330 1.5603261 (L14)
30 -133.894 1.000
31 -451.310 32.851 1.5603261 (L15)
32 -196.891 37.959
33 -511.602 38.337 1.5603261 (L16)
34 -223.931 17.146
35 -1013.395 59.418 1.5603261 (L17)
36 -292.191 1.000
37 507.978 42.880 1.5603261 (L18)
38 -658.005 1.00
39 145.226 49.930 1.5603261 (L19)
40 508.238 1.000
41 120.482 26.465 1.5603261 (L20)
42 * 138.101 4.668
43 64.477 27.099 1.5014548 (L21)
44 69.117 1.000
45 * 68.753 30.683 1.5014548 (L22: Lb)
46 ∞ 1.000 1.4360000 (Lm)
(Wafer surface)

(Aspheric data)
4 sides κ = 0
C ₄ = −3.60477 × 10 ⁻⁷ C ₆ = 2.79854 × 10 ⁻¹¹
C ₈ = −5.821 × 10 ⁻¹⁵ C ₁₀ = −1.46721 × 10 ⁻¹⁹
C ₁₂ = 8.87039 × 10 ⁻²² C ₁₄ = −1.96543 × 10 ⁻²⁵

5 sides κ = 0
C ₄ = −2.03413 × 10 ⁻⁷ C ₆ = −3.775794 × 10 ⁻¹¹
C ₈ = −1.08110 × 10 ⁻¹⁴ C ₁₀ = −2.94945 × 10 ⁻¹⁸
C ₁₂ = −5.66504 × 10 ⁻²³ C ₁₄ = −3.58477 × 10 ⁻²⁵

7 surfaces κ = 0
C ₄ = 1.51456 × 10 ⁻⁷ C ₆ = 1.80661 × 10 ⁻¹²
C ₈ = −6.96213 × 10 ⁻¹⁶ C ₁₀ = −1.02068 × 10 ⁻¹⁹
C ₁₂ = 2.43555 × 10 ⁻²³ C ₁₄ = −1.33980 × 10 ⁻²⁷

20 faces κ = 0
C ₄ = 7.83311 × 10 ⁻⁸ C ₆ = 1.94639 × 10 ⁻¹²
C ₈ = −2.43246 × 10 ⁻¹⁶ C ₁₀ = 2.35542 × 10 ⁻²²
C ₁₂ = -2.30512 × 10 ⁻²⁴ C ₁₄ = 5.06932 × 10 ⁻³⁰

23 κ = 0
C ₄ = −3.882869 × 10 ⁻⁷ C ₆ = 6.221846 × 10 ⁻¹¹
C ₈ = 4.44870 × 10 ⁻¹⁶ C ₁₀ = −4.66684 × 10 ⁻¹⁸
C ₁₂ = 1.03986 × 10 ⁻²¹ C ₁₄ = −7.58461 × 10 ⁻²⁶

26 surfaces κ = 0
C ₄ = -1.91841 × 10 ⁻⁷ C ₆ = 5.4352 × 10 ⁻¹²
C ₈ = 1.15940 × 10 ⁻¹⁴ C ₁₀ = −5.44096 × 10 ⁻¹⁸
C ₁₂ = 8.52657 × 10 ⁻²² C ₁₄ = −4.99161 × 10 ⁻²⁶

28 faces κ = 0
C ₄ = −7.69999 × 10 ⁻⁸ C ₆ = 3.41934 × 10 ⁻¹¹
C ₈ = −9.48474 × 10 ⁻¹⁵ C ₁₀ = 1.28921 × 10 ⁻¹⁸
C ₁₂ = −8.40171 × 10 ⁻²³ C ₁₄ = 1.92065 × 10 ⁻²⁷

29 faces κ = 0
C ₄ = −1.58935 × 10 ⁻⁷ C ₆ = 1.36527 × 10 ⁻¹¹
C ₈ = −1.48398 × 10 ⁻¹⁵ C ₁₀ = 1.23894 × 10 ⁻¹⁹
C ₁₂ = −8.332766 × 10 ⁻²⁴ C ₁₄ = 3.660274 × 10 ⁻²⁸

42 plane κ = 0
C ₄ = −1.84521 × 10 ⁻⁷ C ₆ = 6.23581 × 10 ⁻¹²
C ₈ = 1.88736 × 10 ⁻¹⁵ C ₁₀ = −3.46754 × 10 ⁻¹⁹
C ₁₂ = 2.73631 × 10 ⁻²³ C ₁₄ = −7.3004 × 10 ⁻²⁸

45 faces κ = 0
C ₄ = −1.81116 × 10 ⁻⁷ C ₆ = 3.444740 × 10 ⁻¹¹
C ₈ = 8.13180 × 10 ⁻¹⁵ C ₁₀ = 2.96840 × 10 ⁻¹⁸
C ₁₂ = −6.71340 × 10 ⁻²¹ C ₁₄ = 2.66186 × 10 ⁻²⁴

(Values for conditional expressions)
φmax = 300mm
φo = 28mm
(1) φmax / φo = 10.714

  FIG. 4 is a diagram showing transverse aberration in the first example. In the aberration diagrams, Y indicates the image height. As is apparent from the aberration diagram of FIG. 4, in the first example, in the projection optical system having a projection magnification of 1/4, an extremely large image side is obtained using ArF excimer laser light having a wavelength of 193.306 nm. Although the numerical aperture (NA = 1.2) is secured, it can be seen that the aberration is well corrected in the image circle having a radius of 7 mm.

  FIG. 5 is a diagram showing the relationship among the shot area, the partial exposure area, and the still exposure area in the first embodiment. As shown in FIG. 5, in the first embodiment, a rectangular shot region 51 having a size of 33 mm in the Y direction and 26 mm in the X direction is formed, and two rectangular shapes having a size of 33 mm in the Y direction and 13 mm in the X direction. It is divided into partial exposure areas 51a and 51b. On the other hand, in the image circle having a radius of 7 mm of the projection optical system PL, a rectangular still exposure region 51c of 5 mm in the Y direction and 13 mm in the X direction is set.

  In the first embodiment, for example, a 6-inch reticle R is used to perform scan exposure on the first partial exposure region 51a having a size half that of the shot region 51. At the time of scan exposure to the first partial exposure area 51a, the still exposure area 51c moves in the −Y direction from the end position on the + Y direction side to the end position on the −Y direction side in the first partial exposure area 51a. Then, the wafer stage WS and by extension the wafer W is moved in the + Y direction. Then, in response to the movement of the wafer W in the + Y direction, the reticle stage RS and consequently the reticle R are moved in the −Y direction.

  Next, scan exposure is performed on the second partial exposure region 51 b having a size half that of the shot region 51 without exchanging the reticle R. However, prior to the scanning exposure to the second partial exposure area 51b, the stationary exposure area 51c is located at the −Y direction end of the second partial exposure area 51b from the −Y direction end position of the first partial exposure area 51a. The wafer stage WS and, by extension, the wafer W is stepped by 13 mm in the −X direction so as to move to the partial position in the + X direction. Then, in order to correspond to the step movement of the wafer W in the −X direction, the reticle stage RS and, consequently, the reticle R are stepped by 52 mm in the + X direction.

  At the time of scan exposure on the second partial exposure area 51b, the stationary exposure area 51c moves in the + Y direction from the end position on the −Y direction side to the end position on the + Y direction side in the second partial exposure area 51b. Wafer stage WS and, consequently, wafer W are moved in the -Y direction. Then, in response to the movement of the wafer W in the −Y direction, the reticle stage RS and, consequently, the reticle R are moved in the + Y direction. In the first partial exposure area 51a, the scan exposure may be started so that the still exposure area 51c is moved in the + Y direction from the end position on the −Y direction side.

  Thus, in the first embodiment, it is necessary to transfer the reticle pattern to one predetermined size shot area 51 by scanning exposure to the two partial exposure areas 51a and 51b without causing an increase in the size of the projection optical system PL. An effective imaging area (image field) having a required size can be ensured. Further, since pure water is interposed as a medium having a high refractive index in the optical path between the wafer (photosensitive substrate) W, a high-resolution projection optical system PL having a large effective image-side numerical aperture is provided. Can be realized.

  As a result, good projection exposure with high resolution can be performed according to the stitching method using the relatively small projection optical system PL according to the first embodiment. For more detailed configuration and operation of the stitching type exposure apparatus, refer to, for example, Japanese Patent No. 3316754, Japanese Patent Laid-Open No. 8-330220 (and corresponding US Pat. No. 6,295,119), and the like. Can do.

[Second Embodiment]
FIG. 6 is a diagram showing a lens configuration of the projection optical system according to the second example of the present embodiment. Referring to FIG. 6, the projection optical system PL of the second embodiment includes, in order from the reticle side, a plane parallel plate P1, a biconcave lens L1 having an aspherical concave surface facing the wafer side, and an aspherical shape on the reticle side. Negative meniscus lens L2 with the concave surface facing the lens, positive meniscus lens L3 with the aspherical concave surface facing the reticle side, biconvex lens L4, biconvex lens L5, biconvex lens L6, and convex surface facing the reticle side A positive meniscus lens L7, a positive meniscus lens L8 having a convex surface facing the reticle, a positive meniscus lens L9 having an aspherical concave surface facing the wafer, a negative meniscus lens L10 having a convex surface facing the reticle, and a reticle A biconcave lens L11 with an aspherical concave surface facing the side, a negative meniscus lens L12 with an aspherical concave surface facing the wafer, and an aspherical shape on the wafer side A biconcave lens L13 having a concave surface, a positive meniscus lens L14 having an aspheric concave surface facing the reticle, a positive meniscus lens L15 having a concave surface facing the reticle, and a positive meniscus lens L16 having a concave surface facing the reticle A positive meniscus lens L17 having a concave surface facing the reticle, a biconvex lens L18, a positive meniscus lens L19 having a convex surface facing the reticle, a positive meniscus lens L20 having an aspheric concave surface facing the wafer, A positive meniscus lens L21 having a convex surface facing the reticle side and a plano-convex lens L22 (boundary lens Lb) having an aspherical convex surface facing the reticle side.

  Also in the second example, as in the first example, the optical path between the plano-convex lens L22 as the boundary lens Lb and the wafer W is filled with a medium Lm made of pure water. The lenses L21 and L22 (Lb) are made of fluorite, and the other lens components are made of quartz. The following table (2) lists the values of the specifications of the projection optical system PL according to the second example.

Table 2
(Main specifications)
λ = 193.306 nm
β = -1 / 5
NA = 1.2
φo = 35mm
φi = 7mm

(Optical member specifications)
Surface number r dn optical member (reticle surface) 39.128
1 ∞ 4.242 1.5603261 (P1)
2 ∞ 3.103
3 -1120.724 14.000 1.5603261 (L1)
4 * 147.421 31.308
5 * -68.728 14.000 1.5603261 (L2)
6 -7403.000 12.107
7 * -194.623 44.967 1.5603261 (L3)
8 -125.000 1.000
9 2000.000 37.115 1.5603261 (L4)
10 -400.000 1.000
11 758.189 58.479 1.5603261 (L5)
12 -351.098 25.253
13 741.225 60.000 1.5603261 (L6)
14 -1860.768 1.000
15 259.706 32.011 1.5603261 (L7)
16 469.076 1.000
17 160.278 38.364 1.5603261 (L8)
18 210.000 2.400
19 136.997 37.617 1.5603261 (L9)
20 * 186.302 29.491
21 3292.401 60.000 1.5603261 (L10)
22 89.885 47.414
23 * -201.039 14.000 1.5603261 (L11)
24 114.173 11.356
25 354.751 14.000 1.5603261 (L12)
26 * 124.821 16.381
27 -1443.830 14.000 1.5603261 (L13)
28 * 433.445 23.665
29 * -670.291 36.731 1.5603261 (L14)
30 -131.312 1.000
31 -372.662 33.374 1.5603261 (L15)
32 -180.491 46.358
33 -432.487 40.119 1.5603261 (L16)
34 -215.706 28.798
35 -1240.698 60.000 1.5603261 (L17)
36 -306.986 1.000
37 466.924 44.386 1.5603261 (L18)
38 -677.350 1.000
39 135.740 51.010 1.5603261 (L19)
40 377.325 1.000
41 107.976 28.677 1.5603261 (L20)
42 * 123.160 1.000
43 69.066 28.328 1.5014548 (L21)
44 60.410 2.205
45 * 56.397 30.225 1.5014548 (L22: Lb)
46 ∞ 1.000 1.4360000 (Lm)
(Wafer surface)

(Aspheric data)
4 sides κ = 0
C ₄ = −2.66071 × 10 ⁻⁷ C ₆ = 2.9741 × 10 ⁻¹¹
C ₈ = −4.776373 × 10 ⁻¹⁵ C ₁₀ = 5.01880 × 10 ⁻¹⁹
C ₁₂ = 2.667967 × 10 ⁻²² C ₁₄ = −5.77093 × 10 ⁻²⁶

5 sides κ = 0
C ₄ = −1.18693 × 10 ⁻⁷ C ₆ = −2.14738 × 10 ⁻¹¹
C ₈ = −4.39761 × 10 ⁻¹⁵ C ₁₀ = −1.35408 × 10 ⁻¹⁹
C ₁₂ = −3.19642 × 10 ⁻²² C ₁₄ = 5.445617 × 10 ⁻²⁶

7 surfaces κ = 0
C ₄ = 1.30657 × 10 ⁻⁷ C ₆ = 3.62264 × 10 ⁻¹²
C ₈ = −7.14187 × 10 ⁻¹⁶ C ₁₀ = −7.88822 × 10 ⁻²⁰
C ₁₂ = 1.776092 × 10 ⁻²³ C ₁₄ = −8.551512 × 10 ⁻²⁸

20 faces κ = 0
C ₄ = 5.51155 × 10 ⁻⁸ C ₆ = 2.46578 × 10 ⁻¹³
C ₈ = 1.773270 × 10 ⁻¹⁷ C ₁₀ = −2.08719 × 10 ⁻²²
C ₁₂ = −2.44553 × 10 ⁻²⁶ C ₁₄ = −1.29454 × 10 ⁻²⁹

23 κ = 0
C ₄ = −3.221659 × 10 ⁻⁷ C ₆ = 5.36890 × 10 ⁻¹¹
C ₈ = −1.57630 × 10 ⁻¹⁵ C ₁₀ = −3.52310 × 10 ⁻¹⁸
C ₁₂ = 8.336219 × 10 ⁻²² C ₁₄ = −6.228614 × 10 ⁻²⁶

26 surfaces κ = 0
C ₄ = −1.62042 × 10 ⁻⁷ C ₆ = 1.76015 × 10 ⁻¹²
C ₈ = 1.01105 × 10 ⁻¹⁴ C ₁₀ = −4.956645 × 10 ⁻¹⁸
C ₁₂ = 7.94312 × 10 ⁻²² C ₁₄ = −4.779966 × 10 ⁻²⁶

28 faces κ = 0
C ₄ = −7.04711 × 10 ⁻⁸ C ₆ = 3.09435 × 10 ⁻¹¹
C ₈ = −9.006382 × 10 ⁻¹⁵ C ₁₀ = 1.266627 × 10 ⁻¹⁸
C ₁₂ = −8.63134 × 10 ⁻²³ C ₁₄ = 2.334101 × 10 ⁻²⁷

29 faces κ = 0
C ₄ = −1.47315 × 10 ⁻⁷ C ₆ = 1.28450 × 10 ⁻¹¹
C ₈ = −1.38349 × 10 ⁻¹⁵ C ₁₀ = 1.1203 × 10 ⁻¹⁹
C ₁₂ = −7.991413 × 10 ⁻²⁴ C ₁₄ = 3.353535 × 10 ⁻²⁸

42 plane κ = 0
C ₄ = −1.93501 × 10 ⁻⁷ C ₆ = 5.46290 × 10 ⁻¹²
C ₈ = 2.10000 × 10 ⁻¹⁵ C ₁₀ = −4.300324 × 10 ⁻¹⁹
C ₁₂ = 3.31300 × 10 ⁻²³ C ₁₄ = −9.333193 × 10 ⁻²⁸

45 faces κ = 0
C ₄ = −4.26845 × 10 ⁻⁷ C ₆ = −7.56600 × 10 ⁻¹¹
C ₈ = 1.00727 × 10 ⁻¹⁴ C ₁₀ = −2.662595 × 10 ⁻¹⁸
C ₁₂ = −1.17646 × 10 ⁻²⁰ C ₁₄ = 4.62437 × 10 ⁻²⁴

(Values for conditional expressions)
φmax = 300mm
φo = 35mm
(1) φmax / φo = 8.571

  FIG. 7 is a diagram showing transverse aberration in the second example. In the aberration diagrams, Y indicates the image height. As is apparent from the aberration diagram of FIG. 7, in the second embodiment, a very large image side is obtained using ArF excimer laser light having a wavelength of 193.306 nm in a projection optical system having a projection magnification of 1/5. Although the numerical aperture (NA = 1.2) is secured, it can be seen that the aberration is well corrected in the image circle having a radius of 7 mm.

  FIG. 8 is a diagram showing the relationship among the shot area, the partial exposure area, and the still exposure area in the second embodiment. As shown in FIG. 8, in the second embodiment, a rectangular shot region 52 having a size of 22 mm in the Y direction and 26 mm in the X direction, and two rectangular shapes having a size of 22 mm in the Y direction and 13 mm in the X direction. It is divided into partial exposure areas 52a and 52b. On the other hand, a rectangular still exposure region 52c of 5 mm in the Y direction and 13 mm in the X direction is set in the image circle having a radius of 7 mm of the projection optical system PL.

  In the second embodiment, for example, a 6-inch reticle R is used to perform scan exposure on the first partial exposure region 52a having a size half that of the shot region 52. During the scan exposure to the first partial exposure area 52a, the still exposure area 52c moves in the −Y direction from the end position on the + Y direction side to the end position on the −Y direction side in the first partial exposure area 52a. Then, the wafer stage WS and by extension the wafer W is moved in the + Y direction. Then, in response to the movement of the wafer W in the + Y direction, the reticle stage RS and consequently the reticle R are moved in the −Y direction.

  Next, scan exposure is performed on the second partial exposure region 52b having a size half that of the shot region 52 without exchanging the reticle R. However, prior to the scanning exposure to the second partial exposure region 52b, the stationary exposure region 52c is located at the −Y direction end of the second partial exposure region 52b from the end position of the first partial exposure region 52a on the −Y direction side. The wafer stage WS and, consequently, the wafer W are stepped by 13 mm in the −X direction so as to move in the + X direction to the partial position. Then, in order to correspond to the step movement of the wafer W in the −X direction, the reticle stage RS, and hence the reticle R, is stepped by 65 mm in the + X direction.

  At the time of scan exposure to the second partial exposure area 52b, the still exposure area 52c moves in the + Y direction from the end position on the −Y direction side to the end position on the + Y direction side in the second partial exposure area 52b. Wafer stage WS and, consequently, wafer W are moved in the -Y direction. Then, in response to the movement of the wafer W in the −Y direction, the reticle stage RS and, consequently, the reticle R are moved in the + Y direction. In the first partial exposure area 52a, the scan exposure may be started so that the still exposure area 52c is moved in the + Y direction from the end position on the −Y direction side.

  Thus, also in the second embodiment, the reticle pattern is transferred to one shot area 52 of a predetermined size by scanning exposure on the two partial exposure areas 52a and 52b without causing an increase in the size of the projection optical system PL. An effective imaging area (image field) having a required required size can be secured. Further, since pure water is interposed as a medium having a high refractive index in the optical path between the wafer (photosensitive substrate) W, a high-resolution projection optical system PL having a large effective image-side numerical aperture is provided. Can be realized. As a result, by using the relatively small projection optical system PL according to the second embodiment, it is possible to perform good projection exposure with high resolution according to the stitching method.

[Third embodiment]
FIG. 9 is a diagram showing a lens configuration of the projection optical system according to the second example of the present embodiment. Referring to FIG. 9, the projection optical system PL of the second embodiment includes, in order from the reticle side, a plane parallel plate P1, a biconcave lens L1 having an aspherical concave surface facing the wafer side, and an aspherical shape on the reticle side. Negative meniscus lens L2 with the concave surface facing the lens, positive meniscus lens L3 with the aspherical concave surface facing the reticle side, biconvex lens L4, biconvex lens L5, biconvex lens L6, and convex surface facing the reticle side A positive meniscus lens L7, a positive meniscus lens L8 having a convex surface facing the reticle, a positive meniscus lens L9 having an aspherical concave surface facing the wafer, a negative meniscus lens L10 having a convex surface facing the reticle, and a reticle A biconcave lens L11 with an aspherical concave surface facing the side, a negative meniscus lens L12 with an aspherical concave surface facing the wafer, and an aspherical shape on the wafer side A biconcave lens L13 having a concave surface, a positive meniscus lens L14 having an aspheric concave surface facing the reticle, a positive meniscus lens L15 having a concave surface facing the reticle, and a positive meniscus lens L16 having a concave surface facing the reticle A positive meniscus lens L17 having a concave surface facing the reticle, a biconvex lens L18, a positive meniscus lens L19 having a convex surface facing the reticle, a positive meniscus lens L20 having an aspheric concave surface facing the wafer, A positive meniscus lens L21 having a convex surface facing the reticle side and a plano-convex lens L22 (boundary lens Lb) having an aspherical convex surface facing the reticle side.

  In the third embodiment, similarly to the first and second embodiments, the optical path between the plano-convex lens L22 as the boundary lens Lb and the wafer W is filled with a medium Lm made of pure water. The lenses L21 and L22 (Lb) are made of fluorite, and the other lens components are made of quartz. The following table (3) lists the values of the specifications of the projection optical system PL according to the third example.

Table 3
(Main specifications)
λ = 193.306 nm
β = -1 / 4
NA = 1.2
φo = 52.8mm
φi = 13.2mm

(Optical member specifications)
Surface number r dn optical member (reticle surface) 41.959
1 ∞ 8.000 1.5603261 (P1)
2 ∞ 5.852
3 -2113.365 14.000 1.5603261 (L1)
4 * 221.428 46.651
5 * -110.397 14.003 1.5603261 (L2)
6 -2038.116 14.952
7 * -268.471 60.000 1.5603261 (L3)
8 -163.574 2.204
9 787.073 47.564 1.5603261 (L4)
10 -1199.653 69.409
11 1481.028 56.029 1.5603261 (L5)
12 -900.000 1.000
13 889.835 59.955 1.5603261 (L6)
14 -1400.966 1.000
15 399.864 48.700 1.5603261 (L7)
16 886.381 1.000
17 263.334 41.519 1.5603261 (L8)
18 353.549 1.000
19 184.590 61.940 1.5603261 (L9)
20 * 302.692 40.787
21 2236.773 35.719 1.5603261 (L10)
22 133.772 91.786
23 * -236.082 14.006 1.5603261 (L11)
24 222.881 17.448
25 518.618 14.018 1.5603261 (L12)
26 * 223.081 29.074
27 -2658.035 17.547 1.5603261 (L13)
28 * 817.034 43.358
29 * -918.788 60.000 1.5603261 (L14)
30 -231.616 1.000
31 -870.224 53.941 1.5603261 (L15)
32 -321.031 102.844
33 -835.483 60.543 1.5603261 (L16)
34 -380.671 47.589
35 -3293.468 59.159 1.5603261 (L17)
36 -571.474 1.001
37 951.991 65.054 1.5603261 (L18)
38 -1182.645 1.001
39 252.145 79.173 1.5603261 (L19)
40 774.296 1.001
41 203.245 44.417 1.5603261 (L20)
42 * 277.487 1.000
43 111.053 49.176 1.5014548 (L21)
44 73.419 11.556
45 * 82.853 60.000 1.5014548 (L22: Lb)
46 ∞ 1.000 1.4360000 (Lm)
(Wafer surface)

(Aspheric data)
4 sides κ = 0
C ₄ = −8.42204 × 10 ⁻⁸ C ₆ = 2.80152 × 10 ⁻¹²
C ₈ = −2.22208 × 10 ⁻¹⁶ C ₁₀ = 4.992545 × 10 ⁻²¹
C ₁₂ = 1.55578 × 10 ⁻²⁴ C ₁₄ = −1.36027 × 10 ⁻²⁸

5 sides κ = 0
C ₄ = -1.78733 × 10 ⁻⁸ C ₆ = −5.09565 × 10 ⁻¹²
C ₈ = −1.32647 × 10 ⁻¹⁶ C ₁₀ = −1.78491 × 10 ⁻²⁰
C ₁₂ = −1.09697 × 10 ⁻²⁴ C ₁₄ = −2.665434 × 10 ⁻²⁸

7 surfaces κ = 0
C ₄ = 3.77905 × 10 ⁻⁸ C ₆ = 1.98775 × 10 ⁻¹²
C ₈ = −1.07206 × 10 ⁻¹⁶ C ₁₀ = −4.95516 × 10 ⁻²¹
C ₁₂ = 5.225305 × 10 ⁻²⁵ C ₁₄ = −1.31079 × 10 ⁻²⁹

20 faces κ = 0
C ₄ = 1.28527 × 10 ⁻⁸ C ₆ = −1.54020 × 10 ⁻¹³
C ₈ = −2.38430 × 10 ⁻¹⁸ C ₁₀ = −4.555067 × 10 ⁻²⁴
C ₁₂ = -2.97021 × 10 ⁻²⁷ C ₁₄ = −1.25981 × 10 ⁻³²

23 κ = 0
C ₄ = −6.28820 × 10 ⁻⁸ C ₆ = 4.17470 × 10 ⁻¹²
C ₈ = −1.61854 × 10 ⁻¹⁶ C ₁₀ = −7.84123 × 10 ⁻²¹
C ₁₂ = 8.994065 × 10 ⁻²⁵ C ₁₄ = −2.289944 × 10 ⁻²⁹

26 surfaces κ = 0
C ₄ = −2.77704 × 10 ⁻⁸ C ₆ = 6.66482 × 10 ⁻¹³
C ₈ = 5.996372 × 10 ⁻¹⁷ C ₁₀ = −1.90885 × 10 ⁻²⁰
C ₁₂ = 1.114332 × 10 ⁻²⁴ C ₁₄ = −2.37083 × 10 ⁻²⁹

28 faces κ = 0
C ₄ = −7.227736 × 10 ⁻⁹ C ₆ = 1.31053 × 10 ⁻¹²
C ₈ = −1.34460 × 10 ⁻¹⁶ C ₁₀ = 5.997618 × 10 ⁻²¹
C ₁₂ = −1.10021 × 10 ⁻²⁵ C ₁₄ = 3.187721 × 10 ⁻³¹

29 faces κ = 0
C ₄ = −2.419434 × 10 ⁻⁸ C ₆ = 5.16680 × 10 ⁻¹³
C ₈ = −1.83503 × 10 ⁻¹⁷ C ₁₀ = 4.225022 × 10 ⁻²²
C ₁₂ = -1.00631 × 10 ⁻²⁶ C ₁₄ = 1.53135 × 10 ⁻³¹

42 plane κ = 0
C ₄ = −1.83510 × 10 ⁻⁸ C ₆ = 1.51025 × 10 ⁻¹³
C ₈ = 1.31925 × 10 ⁻¹⁷ C ₁₀ = −5.95 100 × 10 ⁻²²
C ₁₂ = 1.20766 × 10 ⁻²⁶ C ₁₄ = −8.772208 × 10 ⁻³²

45 faces κ = 0
C ₄ = 2.18842 × 10 ⁻⁸ C ₆ = 1.04930 × 10 ⁻¹²
C ₈ = 4.59769 × 10 ⁻¹⁶ C ₁₀ = −1.35609 × 10 ⁻¹⁹
C ₁₂ = 4.222209 × 10 ⁻²³ C ₁₄ = −7.03010 × 10 ⁻²⁷

(Values for conditional expressions)
φmax = 500mm
φo = 52.8mm
(1) φmax / φo = 9.470

  FIG. 10 is a diagram showing transverse aberration in the third example. In the aberration diagrams, Y indicates the image height. As is apparent from the aberration diagram of FIG. 10, in the third example, a very large image side is obtained using ArF excimer laser light having a wavelength of 193.306 nm in a projection optical system having a projection magnification of 1/4. Although the numerical aperture (NA = 1.2) is secured, it can be seen that the aberration is well corrected in the image circle having a radius of 13.2 mm.

  FIG. 11 is a diagram showing a relationship between a shot area and a static exposure area in the third embodiment. As shown in FIG. 11, in the third embodiment, a rectangular shot region 53 of 33 mm in the Y direction and 25 mm in the X direction is within the Y direction in the image circle having a radius of 13.2 mm of the projection optical system PL. A rectangular still exposure region 53c of 8 mm and 25 mm in the X direction is set. In the third embodiment, for example, a 6-inch reticle R is used to perform scan exposure on the shot area 53.

  At the time of scan exposure to the shot area 53, the wafer stage WS is moved so that the stationary exposure area 53c moves in the −Y direction from the end position on the + Y direction side to the end position on the −Y direction side in the shot area 53. As a result, the wafer W is moved in the + Y direction. Then, in response to the movement of the wafer W in the + Y direction, the reticle stage RS and consequently the reticle R are moved in the −Y direction. In the shot area 53, the scan exposure may be started so that the still exposure area 53c is moved in the + Y direction from the end position on the −Y direction side.

  Thus, in the third embodiment, the required size required to transfer the reticle pattern to one shot area 53 of a predetermined size by one scan exposure without increasing the size of the projection optical system PL is effective. An imaging region (image field) can be secured. Further, since pure water is interposed as a medium having a high refractive index in the optical path between the wafer (photosensitive substrate) W, a high-resolution projection optical system PL having a large effective image-side numerical aperture is provided. Can be realized.

  In the first and second embodiments described above, one shot area is divided into two partial exposure areas, and the scan direction to the first partial exposure area and the scan direction to the second partial exposure area are determined. The setting is reversed. However, the present invention is not limited to this, and the scan direction to the first partial exposure area and the scan direction to the second partial exposure area in one shot area can be set to be the same. In this case, after the scan exposure to the first partial exposure region is sequentially performed for each shot region, the scan exposure to the second partial exposure region is sequentially performed for each shot region. Alternatively, the exposure to each shot area is sequentially performed while continuously performing the scan exposure to the first partial exposure area and the scan exposure to the second partial exposure area in one shot area.

  In the first and second embodiments described above, one shot area is equally divided into two partial exposure areas, but the two partial exposure areas are partially overlapped, so-called partial overlap. Exposure can also be performed. In the first and second embodiments described above, one shot area is divided into two partial exposure areas, and each partial exposure area is scanned once. However, at least one partial exposure is performed. Double exposure can also be performed on the area.

  In the exposure apparatus of the above-described embodiment, the reticle (mask) is illuminated by the illumination device (illumination process), and the transfer pattern formed on the mask is exposed to the photosensitive substrate using the projection optical system (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. 12 for an example of a technique 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 301 of FIG. 12, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the one lot of wafers. Thereafter, in step 303, using the exposure apparatus of the present embodiment, the image of the pattern 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 304, the photoresist on the one lot of wafers is developed, and in step 305, 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 301 to 305, a metal is 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. 13, in a pattern forming process 401, a so-called photolithography process is performed in which a mask pattern is transferred and exposed to a photosensitive substrate (such as a glass substrate coated with a resist) using the exposure apparatus of the present embodiment. 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 undergoes 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 402.

  Next, in the color filter forming step 402, 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 step 402, a cell assembly step 403 is executed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like.

  In the cell assembly step 403, for example, liquid crystal is injected between the substrate having the predetermined pattern obtained in the pattern formation step 401 and the color filter obtained in the color filter formation step 402, and a liquid crystal panel (liquid crystal cell) is obtained. ). Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described 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 ArF excimer laser light source is used. However, the present invention is not limited to this, and other appropriate light sources can also be used. 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 projection optical systems. Can also be applied.

It is a figure which shows schematically the structure of the exposure apparatus concerning embodiment of this invention. It is a figure which shows schematically the structure from the boundary lens in each Example to a wafer. It is a figure which shows the lens structure of the projection optical system concerning the 1st Example of this embodiment. It is a figure which shows the lateral aberration in 1st Example. It is a figure which shows the relationship between the shot area | region in the 1st Example, a partial exposure area | region, and a static exposure area | region. It is a figure which shows the lens structure of the projection optical system concerning 2nd Example of this embodiment. It is a figure which shows the lateral aberration in 2nd Example. It is a figure which shows the relationship between the shot area in a 2nd Example, a partial exposure area | region, and a static exposure area | region. It is a figure which shows the lens structure of the projection optical system concerning 3rd Example of this embodiment. It is a figure which shows the lateral aberration in 3rd Example. It is a figure which shows the relationship between the shot area | region and static exposure area | region in 3rd Example. It is a flowchart of the method at the time of obtaining the semiconductor device as a microdevice. It is a flowchart of the method at the time of obtaining the liquid crystal display element as a microdevice.

Explanation of symbols

Lb Boundary lens Lm Medium (pure water)
Li Each lens component 100 Laser light source IL Illumination optical system R Reticle RS Reticle stage PL Projection optical system W Wafer WS Wafer stage

Claims (12)

In a projection optical system for forming a reduced image of the first surface on the second surface,
When the maximum object height on the first surface is φo, and the maximum effective diameter value of all the effective diameters of the lenses in the projection optical system is φmax,
6.6 <φmax / φo <12
A projection optical system characterized by satisfying the following conditions. The projection optical system according to claim 1, wherein the projection optical system has a projection magnification of about | 1/5 | to about | 1/4 |. When the refractive index of the atmosphere in the optical path of the projection optical system is 1, the optical path between the projection optical system and the second surface is filled with a medium having a refractive index greater than 1.1. The projection optical system according to claim 1, wherein a reduced image of the first surface is formed on the second surface. An illumination process for illuminating the mask set on the first surface, and an image of a pattern formed on the mask via the projection optical system according to any one of claims 1 to 3 on the second surface An exposure method comprising: an exposure step of projecting and exposing on a set photosensitive substrate. In the exposure step, projection exposure is performed on one shot area including two partial exposure areas,
The exposure step includes at least two partial exposure steps of projecting and exposing to the partial exposure region,
5. The exposure method according to claim 4, wherein in the partial exposure step, scanning exposure is performed on the partial exposure region while moving the mask and the photosensitive substrate relative to the projection optical system. The exposure step includes a first partial exposure step of performing scanning exposure on one partial exposure region while relatively moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system; and the projection And a second partial exposure step of performing scanning exposure on the other partial exposure region while relatively moving the mask and the photosensitive substrate in the direction opposite to the predetermined direction with respect to the optical system. The exposure method according to claim 5. The exposure step includes a first partial exposure step of performing scanning exposure on one partial exposure region while relatively moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system; and the projection And a second partial exposure step of performing scanning exposure on the other partial exposure region while moving the mask and the photosensitive substrate relative to the optical system in the predetermined direction. 5. The exposure method according to 5. In the exposure step, projection exposure is performed on a plurality of shot areas,
The exposure step includes a first partial exposure step in which projection exposure is performed on the predetermined partial exposure region in the plurality of shot regions, and a second projection exposure is performed on another partial exposure region in the plurality of shot regions. The exposure method according to claim 5, further comprising a second partial exposure step. 9. The exposure method according to claim 6, wherein the mask is not exchanged between the first partial exposure step and the second partial exposure step. Prior to the exposure step, when the refractive index of the atmosphere in the optical path of the projection optical system is 1, the optical path between the projection optical system and the photosensitive substrate has a refractive index greater than 1.1. The exposure method according to claim 4, further comprising a filling step of filling with a medium. 4. An illumination system for illuminating a mask set on the first surface, and an image of a pattern formed on the mask on a photosensitive substrate set on the second surface. An exposure apparatus comprising the projection optical system according to any one of the above. Scanning exposure to the photosensitive substrate while moving the mask and the photosensitive substrate in a predetermined direction with respect to the projection optical system,
The exposure apparatus according to claim 11, further comprising a mask stage for supporting the mask and moving it stepwise in a direction substantially orthogonal to the predetermined direction.

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