JP2000252206A - Scanning aligner its manufacture, and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To align a scanning direction for a mask and a photosensitive substrate with a projection optical system. SOLUTION: Using a projection optical system 7 provided with at least one reflective surface and a plurality of optical axes bent by the reflective surface, a pattern image of a mask 4 is scanned and exposed on each exposure area of a photosensitive substrate 8. In this case, a scanning direction of the mask and the photosensitive substrate is aligned with the projection optical system, and the mask and the photosensitive substrate are moved along the scanning direction in a condition where alignment have been performed, and the pattern image of the mask is scanned and exposed on each exposure area of the photosensitive substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a scanning exposure apparatus, a method of manufacturing the same, and a scanning exposure method. More specifically, for example, an exposure apparatus used for manufacturing a semiconductor IC or an LSI, wherein a scanning type in which a mask and a photosensitive substrate are moved relative to a reflective or catadioptric projection optical system to perform scanning exposure. A projection exposure apparatus.

[0002]

2. Description of the Related Art The progress of semiconductor technology has been increasing at an increasing rate in recent years, and accordingly, the progress of fine processing technology using a projection exposure apparatus has been remarkable. In a projection exposure apparatus, a fine pattern formed on a mask is transferred to a photosensitive substrate such as a wafer via a projection optical system. At present, for example, a 64 Mbit DRAM is mainly used as a semiconductor device such as a memory, but development to a 256 Mbit DRAM region is being made. With the increase in the degree of integration of semiconductor elements, the exposure light in the projection exposure apparatus is
193n wavelength from 48nm KrF excimer laser light
Practical use has progressed toward m m ArF excimer laser light.

By the way, as the wavelength of exposure light becomes shorter, the types of glass materials (optical materials) that can be used in a projection optical system are significantly restricted. As a result, it is difficult to correct axial chromatic aberration in a conventional refraction type projection optical system. For it,
In a catadioptric projection optical system, axial chromatic aberration can be corrected even if the type of glass material used is limited. The refractive optical system is an optical system mainly including a refractive optical element such as a lens component without including a reflecting mirror having a concave or convex reflecting surface. The catadioptric optical system is an optical system in which a reflecting mirror having a concave or convex reflecting surface and a lens component are mixed. Incidentally, the reflection type optical system is an optical system mainly including a reflecting mirror having a concave or convex reflecting surface without including a lens component.

[0004]

However, in a catadioptric projection optical system, unlike a refraction type projection optical system having only one optical axis extending linearly, the optical path is bent by a reflecting mirror or the like. There will be multiple optical axes. As a result, in a catadioptric projection optical system,
Aberration due to mutual displacement of a plurality of optical axes is likely to occur. In particular, in a catadioptric projection optical system that forms an intermediate image, for example, it is necessary to spatially separate the optical path of light incident on the concave reflecting mirror and the optical path of light reflected from the concave reflecting mirror. The effective exposure area (the area where the exposure visual field can be set effectively) on the transparent substrate is limited.

In an exposure apparatus having a refraction type projection optical system having a single optical axis, the projection optical system is rotationally symmetric with respect to the optical axis unless an optical member rotationally asymmetric with respect to the optical axis is intentionally used. The effective exposure area on the photosensitive substrate is defined as a whole circular area centered on the optical axis with the maximum image height as a radius. Therefore, in the case of a scanning type exposure apparatus that performs scanning exposure by moving the mask and the photosensitive substrate in the scanning direction with respect to the projection optical system, the scanning direction of the mask and the photosensitive substrate is aligned with the projection optical system. It is not necessary that the scanning direction of the mask coincides with the scanning direction of the photosensitive substrate.

However, for example, in a scanning exposure apparatus having a catadioptric projection optical system for forming an intermediate image of a mask, the effective exposure area on the photosensitive substrate is limited as described above, It is not a symmetric area. The exposure visual field on the photosensitive substrate is set, for example, as a slit-like (elongated rectangular) area almost inscribed in the effective exposure area. in this case,
In order to maximize the exposure field within the effective exposure area, the mask and the photosensitive substrate must be moved along a specific axis defined depending on the shape of the effective exposure area. That is, especially in a scanning type exposure apparatus having a catadioptric projection optical system, not only does the scanning direction of the mask coincide with the scanning direction of the photosensitive substrate, but also the scanning direction is positioned with respect to the projection optical system. It is necessary to match.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in consideration of the above circumstances, and provides a scanning type exposure apparatus capable of aligning a scanning direction of a mask and a photosensitive substrate with respect to a projection optical system, a method of manufacturing the same, and An object of the present invention is to provide a scanning exposure method.

[0008]

According to a first aspect of the present invention, there is provided a lighting system for illuminating a mask on which a pattern is formed, at least one reflecting surface and at least one reflecting surface. A plurality of optical axes bent by a reflecting surface, a projection optical system for projecting a pattern image of the mask onto a photosensitive substrate, and a scanning direction of the mask and the photosensitive substrate to the projection optical system. Positioning means for positioning with respect to the projection optical system by the positioning means, moving the mask and the photosensitive substrate along the scanning direction in a state where the position is aligned with the projection optical system, There is provided a scanning type exposure apparatus which scan-exposes a pattern image of the mask on each exposure area of a photosensitive substrate.

According to a preferred first aspect of the first invention, the projection optical system forms an effective exposure area having a predetermined shape on the photosensitive substrate, and is set within the effective exposure area. Projecting a pattern image of the mask under an exposure visual field, the positioning means sets a scanning direction of the mask and the photosensitive substrate along a specific axis defined depending on a shape of the effective exposure area. To align. According to a preferred second aspect of the first invention, in the first aspect described above, further comprising a mask stage that holds and moves the mask, and a substrate stage that holds and moves the photosensitive substrate, A first reflecting member having a reflecting surface attached to the mask stage or the substrate stage and set in parallel to a driving direction of the mask stage or the substrate stage;
A second reflecting member attached to the projection optical system and having a reflecting surface set in parallel to the specific axis; and a reflecting surface of the first reflecting member and a reflecting surface of the second reflecting member. It is preferable to adjust the driving direction of the mask stage or the driving direction of the substrate stage so that are parallel.

Further, according to a preferred third aspect of the first invention, in the second aspect described above, the projection optical system has a concave reflecting mirror, and has a primary pattern of the mask based on light from the mask. A first imaging optical system having a first optical axis for forming an image, and a second imaging system for forming a secondary image of the pattern of the mask on the photosensitive substrate based on light from the primary image. A second imaging optical system having two optical axes, and at least one optical path deflecting member for guiding reflected light from the concave reflecting mirror in the first imaging optical system to the second imaging optical system; Preferably, the reflection surface of the second reflection member is set parallel to a plane including the first optical axis and the second optical axis.

According to a fourth aspect of the present invention, in the above-mentioned third aspect, the projection optical system includes an optical member constituting the first imaging optical system, the optical member being located on the first optical axis. A first barrel member having a cylindrical shape for housing and holding along
A second barrel member having a cylindrical shape for holding and holding an optical member constituting the second imaging optical system along the second optical axis; A guide member is provided so as to be in contact with the outer surface of the cylindrical member and the outer surface of the second lens barrel member, and the second reflecting member is mounted on the guide member. Alternatively, according to a preferred fifth aspect of the first invention, in the third aspect described above, the projection optical system accommodates an optical member constituting the first imaging optical system along the first optical axis. A cylindrical first barrel member for holding, and a cylindrical second barrel member for housing and holding an optical member constituting the second imaging optical system along the second optical axis; And the positioning means has a guide member attached so as to contact an outer surface of the first lens barrel member and an outer surface of the second lens barrel member. A surface is formed on the guide member. Alternatively, according to a preferred sixth aspect of the first invention, in the above third aspect, the at least one
Three optical path deflecting members for reflecting the reflected light from the concave reflecting mirror in the first imaging optical system in a predetermined direction;
A reflecting member, and a fourth reflecting member for reflecting the light reflected by the third reflecting member and guiding the reflected light to the second imaging optical system, wherein the second reflecting member of the positioning unit includes: A reflecting surface is set to be perpendicular to an intersection line between an extending surface of the reflecting surface of the third reflecting member and an extending surface of the reflecting surface of the fourth reflecting member.

According to a second aspect of the present invention, a projection optical system having at least one reflecting surface and a plurality of optical axes bent by the at least one reflecting surface is used.
In a scanning exposure method for scanning and exposing a pattern image of a mask on each exposure region of a photosensitive substrate, an alignment step of aligning a scanning direction of the mask and the photosensitive substrate with respect to the projection optical system; In order to scan and expose the pattern image of the mask on each exposure area of the photosensitive substrate, the mask and the photosensitive substrate are aligned along the scanning direction in the alignment step with respect to the projection optical system. A scanning type exposure method, comprising:

According to a third aspect of the present invention, a projection optical system having at least one reflecting surface and a plurality of optical axes bent by the at least one reflecting surface is provided.
In a method of manufacturing a scanning exposure apparatus that scans and exposes a pattern image of a mask on each exposure area of a photosensitive substrate, a measurement step of measuring the plurality of optical axes when assembling the projection optical system, and a measurement step is performed in the measurement step. In order to move the mask or the photosensitive substrate along a specific axis defined based on the positional relationship between the plurality of optical axes, a mask stage or the photosensitive substrate that holds and moves the mask is moved. An adjusting step of adjusting a driving direction of the substrate stage that is held and moved.

According to a preferred aspect of the third invention, in the measuring step, each of the plurality of optical axes is determined based on reflected light from a lens surface of a lens component positioned and held at a predetermined position in the projection optical system. Is measured. According to another preferred aspect of the third invention, in the measuring step, a reflective member for measurement is positioned with respect to the projection optical system,
It is preferable that each of the plurality of optical axes is measured based on light reflected from a reflection surface of the measurement reflection member.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A so-called reflective or catadioptric projection optical system has a plurality of optical axes bent by at least one reflecting surface. Therefore, when scanning exposure is performed using a reflective or catadioptric projection optical system, an effective exposure area having a shape that is rotationally asymmetric with respect to the optical axis is formed on the photosensitive substrate, and within the effective exposure area. The pattern image of the mask is projected on the photosensitive substrate under the set exposure field. In this case, in order to perform good scanning exposure at high throughput, the specific field defined depending on the shape of the effective exposure area so that the exposure field of view can be set to the maximum within the range of the effective exposure area. It is necessary to move the mask and the photosensitive substrate along the axis.

Therefore, in the present invention, the scanning direction of the mask and the photosensitive substrate is aligned with respect to the projection optical system, and the mask and the photosensitive substrate are moved along the scanning direction in the aligned state. A pattern image of a mask is scanned and exposed on each exposure area of the substrate. According to a specific aspect of the alignment, the first reflecting member attached to the mask stage or the substrate stage and having a reflecting surface set in parallel to the driving direction thereof, and the first reflecting member attached to the projection optical system and described above. And a second reflecting member having a reflecting surface set in parallel to the axis of. The scanning direction of the mask and the photosensitive substrate is adjusted by adjusting the driving direction of the mask stage or the driving direction of the substrate stage so that the reflecting surface of the first reflecting member and the reflecting surface of the second reflecting member are parallel to each other. Align with the projection optical system.

In addition to the above-described embodiments, for example, when assembling a projection optical system, a plurality of optical axes are measured, and a mask or photosensitive member is exposed along a specific axis defined based on a positional relationship between the measured plurality of optical axes. To move the conductive substrate
The driving direction of the mask stage or the substrate stage can be adjusted. As described above, in the present invention, the scanning direction of the mask and the photosensitive substrate is aligned with respect to the projection optical system, and the mask and the photosensitive substrate are moved along the scanning direction in the aligned state. A pattern image of a mask is scanned and exposed on each exposure area of the substrate. Therefore, the exposure field of view can be set to the maximum within the range of the effective exposure area of the projection optical system. As a result, good scanning exposure can be performed with high throughput under the set large exposure field of view.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram schematically showing an overall configuration of a scanning exposure apparatus according to each embodiment of the present invention. In addition,
In FIG. 1, the Z axis is in the normal direction of the wafer surface, the X axis is in the wafer surface parallel to the plane of FIG. 1, and the Y axis is perpendicular to the plane of FIG.
Axis is set.

The exposure apparatus shown in the figure has an ArF excimer laser light source (oscillation center wavelength: 193.3 nm) as the light source 1. The light emitted from the light source 1 in the + X direction is deflected in the −Z direction by the bending mirror 2, and uniformly illuminates the mask 4 via the illumination optical system 3. The illumination optical system 3 includes, for example, a fly-eye lens and an internal reflection type rod integrator to form a surface light source having a predetermined size and shape, and to define the size and shape of an illumination area on the mask 4. And an optical system such as a field stop imaging optical system that projects an image of the field stop onto the mask 4.

The mask 4 is held on a mask stage 6 via a mask holder 5 in parallel with the XY plane. A pattern to be transferred is formed on the mask 4 and has an elongated rectangular shape (hereinafter, referred to as a long side) having a long side along the Y direction and a short side along the X direction in the entire pattern area.
A “slit-like” pattern area is illuminated.
The mask stage 6 is capable of two-dimensional movement along a mask plane (that is, an XY plane) and rotation about an axis parallel to the Z-axis by the action of a drive system (not shown). It is configured to be measured and position controlled by an interferometer 12 using a mirror 11.

Light from the pattern formed on the mask 4 forms a mask pattern image on a wafer 8 as a photosensitive substrate via a catadioptric projection optical system 7. The wafer 8 is held on a wafer stage 10 via a wafer holder 9 in parallel with the XY plane. Then, a slit-shaped exposure having a long side along the Y direction and a short side along the X direction also on the wafer 8 so as to correspond optically to the slit-shaped illumination visual field on the mask 4. A pattern image is formed in the field of view. The wafer stage 10
A two-dimensional movement along the wafer surface (that is, an XY plane) and a rotation around an axis parallel to the Z-axis are possible by the operation of a drive system (not shown). It is configured to be measured and position-controlled by the interferometer 14.

Therefore, the driving system and the interferometer (12,
14), while controlling the position of the mask 4 and the wafer 8, the mask stage 6 and the wafer stage 10 are moved along the short side direction of the slit-shaped exposure field and the illumination field, that is, in the X direction. By synchronously moving the wafer 8, a mask is formed on an area having a width equal to the long side of the exposure field and a length corresponding to the scanning amount (moving amount) of the wafer 8 on the wafer 8. The pattern is scanned and exposed.

FIG. 2 is a diagram showing a lens configuration of the catadioptric projection optical system shown in FIG. FIG. 2 is a cross-sectional view along a plane including the optical axis AX1 of the first imaging optical system and the optical axis AX2 of the second imaging optical system. The illustrated projection optical system 7 includes:
A catadioptric first imaging optical system having an optical axis AX1 parallel to the normal to the pattern surface of the mask 4, and a catadioptric first imaging optical system parallel to the normal to the exposure surface of the wafer 8 (ie, parallel to the optical axis AX1);
A refraction-type second imaging optical system having an optical axis AX2.

The first imaging optical system forms an intermediate image (primary image) of the mask pattern based on the light from the mask 4. Further, the second imaging optical system forms a secondary image of the mask pattern on the wafer 8 based on the light from the intermediate image of the mask pattern. The optical axis A is located near the position where the intermediate image is formed.
A plane reflecting mirror M whose reflecting surface forms an angle of 45 degrees with X1.
2 are arranged. Further, in order to optically connect the first imaging optical system and the second imaging optical system, a reflecting surface which is at an angle of 45 degrees with respect to the optical axis AX2 and is orthogonal to the reflecting surface of the plane reflecting mirror M2. Is disposed.

The catadioptric first imaging optical system includes a mask 4
In order from the incident side of the light from the lens, a plano-concave lens L11 having a flat surface on the incident side, a negative meniscus lens L12 having a concave surface on the incident side, and a positive meniscus lens L having a concave surface on the incident side
13, a biconvex lens L14, a positive meniscus lens L15 having a convex surface facing the incident side, a biconcave lens L16, and a biconvex lens L
17 and a positive meniscus lens L18 having a convex surface facing the incident side.
A negative meniscus lens L19 having a concave surface facing the incident side,
And a concave reflecting mirror M1 having a concave surface facing the incident side. Therefore, the light from the mask 4 enters the concave reflecting mirror M1 via the nine lens components L11 to L19. The light reflected by the concave reflecting mirror M1 has six lens components L19.
Through L14, an intermediate image of the mask pattern is formed near the plane reflecting mirror M2.

The light from the intermediate image of the mask pattern is incident on the refraction type second imaging optical system via the plane reflecting mirror M2 and the plane reflecting mirror M3. The second imaging optical system includes, in order from the incident side of light from the intermediate image, a biconvex lens L21, a negative meniscus lens L22 having a concave surface on the incident side, a negative meniscus lens L23 having a convex surface on the incident side, Biconvex lens L24
A negative meniscus lens L25 having a concave surface facing the incident side,
A positive meniscus lens L26 having a convex surface facing the incident side, a biconvex lens L27, a positive meniscus lens L28 having a convex surface facing the incident side, a biconcave lens L29, a positive meniscus lens L210 having a convex surface facing the incident side, And a convex lens L211.

Therefore, the light incident on the second imaging optical system from the intermediate image of the mask pattern is reflected by the lens components L21 to L21.
A secondary image (reduced image) of the mask pattern is formed in the slit-shaped exposure field on the wafer 8 via 211. Note that an aperture stop S is disposed in the optical path between the biconvex lens L24 and the negative meniscus lens L25. The surface of the negative meniscus lens L23 on the wafer side and the biconcave lens L
The surface on the wafer side of 29 is formed in an aspherical shape. Further, among the lens components constituting the projection optical system 7, the biconvex lens L17 in the first imaging optical system and the biconvex lens L24 in the second imaging optical system are made of fluorite (CaF ₂ crystal) and other lenses. Quartz is used for each component.

As described above, in the catadioptric projection optical system 7, in the first imaging optical system, the light beam entering the concave reflecting mirror M1 from the mask 4 and being reflected by the concave reflecting mirror M1 are reflected by the second imaging optical system. It is necessary to spatially separate the luminous flux going to the system. As a result, as shown in FIG. 3, an area on the wafer 8 that can be used for image formation, that is, an effective exposure area 31
(Shown by oblique lines in the figure) indicates that the radius around the optical axis AX2 is 1
This is less than half of the 6.7 mm circular area. The area actually used for scanning exposure, that is, the exposure visual field 32 has a slit shape of 25 mm × 6 mm, and the distance from the optical axis AX2 to the exposure visual field 32 is 5 mm.

That is, the slit-shaped exposure field 32 is
0.25 from the linear portion of the substantially semicircular effective exposure area 31
mm and are substantially in contact with the arc portion. Referring to FIG. 3, it can be seen that the setting of the exposure field of view 32 with respect to the effective exposure area 31 is a state where only a small margin is allowed. As described above, the effective exposure area 31 has a shape that is rotationally asymmetric with respect to the optical axis AX2, and in order to perform good scanning exposure with the exposure field of view 32 set to the maximum within that range, the mask 4 and the wafer It is necessary to align the scanning direction (scanning direction) 8 along the X direction, that is, to align with the projection optical system 7. Here, X to be aligned in the scanning direction
The direction is a direction along a specific axis defined depending on the shape of the effective exposure area 31 of the projection optical system 7.

Table 1 below summarizes the data values of the projection optical system of this embodiment. In Table (1), λ represents the center wavelength of the exposure light, β represents the projection magnification, and NA represents the image-side numerical aperture. The surface number indicates the order of the surface from the mask side along the direction in which light rays travel from the mask surface, which is the object surface, to the wafer surface, which is the image surface, and r indicates the radius of curvature of each surface (in the case of an aspheric surface, Denotes the radius of curvature of the vertex, d denotes the on-axis interval of each surface, that is, the surface interval, and φ denotes the effective radius of each lens. n is a refractive index with respect to the center wavelength, and n = 1.560326 for quartz and n = 1.5 for fluorite.
01455.

It is assumed that the sign of the surface distance d changes each time it is reflected. Therefore, the sign of the surface distance d is negative in the optical path from the concave reflecting mirror M1 to the plane reflecting mirror M2, negative in the optical path from the plane reflecting mirror M3 to the wafer surface, and positive in the other optical paths. And
In the first imaging optical system, the radius of curvature of the convex surface toward the mask side is positive, and the radius of curvature of the concave surface is negative. In the second imaging optical system, the radius of curvature of the convex surface toward the wafer side is positive, and the radius of curvature of the concave surface is negative.

The height of the aspheric surface in the direction perpendicular to the optical axis is defined as y, and the distance (sag amount) along the optical axis from the tangent plane at the vertex of the aspheric surface to the position on the aspheric surface at the height y is defined as y. Let z be the radius of curvature of the vertex, r be the conic coefficient, and Cn be the nth-order aspherical coefficient, expressed by the following equation (a).

[Number 1] ^{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) table (1), a lens surface formed in an aspherical shape is provided with mark * on the right side of the surface number.

[0033]

[Table 1] (Main specifications) λ = 193.3 nm β = 0.25 NA = 0.75 (Optical member specifications) Surface number rd φ n (Mask surface) 50.0980 1 ∞ 30.8769 77.96 1.560326 (L11) 2 1358.1393 25.6596 82.00 3 -173.9366 29.5956 82.54 1.560326 (L12) 4 -262.5027 3.9549 93.62 5 -243.7585 32.1846 94.30 1.560326 (L13) 6 -198.6141 79.2508 102.23 7 705.6754 29.6916 128.29 1.560326 (L14) 8 -853.6854 7.1157 128.85 93.8 (L15) 10 393.9524 334.9670 126.27 11 -228.4608 20.5261 87.25 1.560326 (L16) 12 324.6767 7.3561 90.62 13 359.7325 40.5663 92.51 1.501455 (L17) 14 -554.2952 58.0131 94.34 15 588.9791 33.3872 97.95 1.560326 15.17. (L19) 18 -1326.9703 25.8354 126.13 19 -367.4917 -25.8354 129.94 (Concave reflector M1) 20 -1326.9703 -25.0000 127.54 1.560326 (L19) 21 -249.4612 -113.1955 117.01 22 3573.1266 -33.3872 112 .48 1.560326 (L18) 23 588.9791 -58.0131 111.89 24 -554.2952 -40.5663 100.25 1.501455 (L17) 25 359.7325 -7.3561 97.36 26 324.6767 -20.5261 94.44 1.560326 (L16) 27 -228.4608 -334.9670 87.51 28 393.9524 -35.0000 93.84 1.560326 29 243.8837 -7.1157 96.50 30 -853.6854 -29.6916 93.81 1.560326 (L14) 31 705.6754 -1.6203 92.09 32 530 530.0000 (plane reflector M2) 33 ∞ -100.0000 140.00 (plane reflector M3) 34 -473.4614 -50.8662 130.00 1.560326 (L21) 35 1218.5628 -18.9785 128.42 36 357.1688 -31.0635 128.11 1.560326 (L22) 37 818.7536 -209.4034 129.93 38 -571.9096 -31.2079 123.89 1.560326 (L23) 39 * -295.8211 -4.7127 119.48 40 -291.2028 -53.9868 119.84 1.501455 (L2469) 41 858 119.00 42 ∞ -24.0577 115.27 (Aperture stop S) 43 719.7751 -25.0000 113.83 1.560326 (L25) 44 6715.0030 -22.3498 117.19 45 -314.9647 -45.0000 124.79 1.560326 (L26) 46 -5036.3103 -16.5385 123.55 47 -265.1907 -45.0000 120.07 1.5 60 326 (L27) 48 9375.9412 -1.1109 116.54 49 -177.9561 -50.1531 103.37 1.560326 (L28) 50 -18823.9455 -4.9217 94.91 51 1624.4953 -25.0000 93.03 1.560326 (L29) 52 * -247.3912 -1.0000 74.54 53 -210.5206 -24.3364 73.210 1.560326 ) 54 -35247.2125 -1.0621 69.21 55 -293.7588 -65.0000 63.01 1.560326 (L211) 56 56893.1197 -12.3837 31.15 ( wafer surface) (aspherical data) r κ C ₄ 39 faces _{^{-295.8211 0.00000 -1.3500 × 10 -8 C 6}} C 8 C ₁₀ -1.2494 × 10 ^-13 -1.3519 × 10 ^-18 -9.1832 × 10 ^-23 C ₁₂ C ₁₄ 3.6 355 × 10 ^-27 -1.6744 × 10 ^-31 r κ C ₄ 52 surface -247.3912 0.00000 -4.8204 × 10 ^-8 C ₆ C ₈ C ₁₀ -1.1379 × 10 ^-12 -6.8704 × 10 ^-17 -2.8172 × 10 ^-21 C ₁₂ C ₁₄ 0.00000 0.00000

FIG. 4 is a diagram schematically showing the mechanical configuration of the catadioptric projection optical system shown in FIG. In FIG.
(A) is a cross-sectional view along a plane including the optical axes AX1 and AX2, (b) and (c) are side views, and (d)
Is a top view. As shown in FIG. 4, a lens component L constituting a catadioptric first imaging optical system having an optical axis AX1
11 to L19 and the concave reflecting mirror M1 are respectively positioned and held at predetermined positions inside a first cylindrical barrel member having a central axis coinciding with the optical axis AX1, that is, the first barrel 41. Also, an optical axis A parallel to the optical axis AX1
The lens components L21 to L211 constituting the refraction-type second imaging optical system having X2 include a cylindrical second barrel member having a central axis coinciding with the optical axis AX2, that is, a second barrel 42.
Are positioned and held at respective predetermined positions inside the.

Further, the plane reflecting mirrors M2 and M3 are held at predetermined positions by holding members 43 having a reference axis AX3. Here, the holding member 4
3 is an axis extending in the X direction in a plane including the optical axes AX1 and AX2 (in the XZ plane), and a ray incident on the plane reflecting mirror M3 along the optical axis AX2 is the plane reflecting mirror M3. Is defined as the path of the reflected light beam when reflected by the plane reflecting mirror M2 along the optical axis AX1.
Is defined as the path of the reflected light beam when the light beam incident on the virtual reflection surface which is an extension of the reflection surface is reflected by the virtual reflection surface. In other words, the plane reflecting mirrors M2 and M3 are positioned with respect to the first imaging optical system and the second imaging optical system such that the optical paths of the two reflected light beams coincide.

The first barrel 41 and the second barrel 42 are
Each is pivotally supported by the gantry 44 at a pivot point. The holding member 43 is directly supported by the gantry 44 via arm portions 43a and 43b protruding from both sides near the center. That is, the gantry 44 is the one common to the first barrel 41, the second barrel 42 and the holding member 43.
A stable support structure. As described above, in each embodiment, it is necessary to move the mask 4 and the wafer 8 along the X direction. In other words, at the time of scanning exposure, the mask 4 and the wafer 8 are moved along a plane including the optical axes AX1 and AX2 or along the reference axis AX3 of the holding member 43.
And need to move.

[First Embodiment] FIG. 5 is a view for explaining a first embodiment in which the driving directions of the mask stage and the wafer stage are aligned with the projection optical system. FIG. 6 is a diagram schematically showing an internal configuration of the autocollimator of FIG. In FIG. 5, a guide member 51 is attached to a first barrel 41 and a second barrel 42 having the same outer diameter (for example, a radius of 240 mm) so as to be in contact with the outer surface. The guide member 51 is provided on the first barrel 41 and the first barrel abutting on the outer surface of the second barrel 42.
It has a surface 51a and a second surface 51b parallel to the first surface 51a. On the second surface 51b side of the guide member 51,
Reflecting member 52 having a reflecting surface parallel to second surface 51b
Is attached. Therefore, the reflection surface 52a of the reflection member 52 is parallel to the first surface 51a of the guide member 51, is parallel to the plane including the optical axes AX1 and AX2, that is, is parallel to the XZ plane, and furthermore, the reference axis AX of the holding member 43.
3 is set in parallel.

On the other hand, as described above, the mask stage 6 can rotate around an axis parallel to the Z axis, and is driven in the X direction during scanning exposure. Therefore, a reflection member 53 having a reflection surface parallel to the driving direction is attached to the mask stage 6. Therefore, while slightly rotating the mask stage 6 around an axis parallel to the Z axis,
Reflection surface 5 of reflection member 52 attached to guide member 51
2a and the reflecting member 53 attached to the mask stage 6
Mask stage 6 so that the reflection surface 53a of the
Is adjusted, the scanning direction of the mask 4 can be made to coincide with the reference axis AX3 of the holding member 43, that is, the scanning direction of the mask 4 can be aligned with the projection optical system 7. The parallelism between the reflecting surface 52a of the reflecting member 52 and the reflecting surface 53a of the reflecting member 53 can be optically confirmed using, for example, an autocollimator 54.

As shown in FIG. 6, the auto collimator 54
Is, for example, a He-Ne laser light source 61 as a light source.
(An oscillation wavelength of 633 nm). The parallel light beam supplied from the light source 61 enters the half prism 63 after the cross-sectional shape is shaped through the expander lens system 62. The parallel light flux reflected by the half prism 63 is
The light is emitted from the autocollimator 54. Here, referring to FIG. 5, some of the parallel light beams emitted from the autocollimator 54 along the + Y direction directly enter the reflecting member 53 attached to the mask stage 6. The light beam reflected in the −Y direction on the reflecting surface 53 a of the reflecting member 53 returns to the autocollimator 54.

Some of the parallel light beams emitted from the autocollimator 54 along the + Y direction are transmitted to the reflecting member 52 attached to the guide member 51 via the optical path deflecting member 55 in the + Y direction. Incident along. The optical path deflecting member 55 is composed of a pair of reflecting mirrors 55a and 55b having reflecting surfaces parallel to each other. The reflecting mirror 55a reflects a light beam incident from the autocollimator 54 along the + Y direction in the -X direction, and then reflects the light beam. + At 55b
Reflects along the Y direction. That is, the optical path deflecting member 55
Deflects the incident light beam from the autocollimator 54 twice, and then emits the light beam in a direction parallel to the incident direction.
Therefore, the light beam reflected in the −Y direction on the reflecting surface 52 a of the reflecting member 52 returns to the autocollimator 54 via the optical path deflecting member 55.

Referring again to FIG. 6, the reflected light flux from the reflecting member 52 and the reflected light flux from the reflecting member 53 returned to the autocollimator 54 enter the half prism 63. The light beam transmitted through the half prism 63 is once condensed on a reticle 65 as a reference plate (collimation plate) via a condenser lens 64, and then reaches a detector 67 via an imaging lens 66. Thus, based on the output of the detector 67, the parallelism between the reflection surface 52a of the reflection member 52 and the reflection surface 53a of the reflection member 53 can be optically detected. In the autocollimator 54, by using an eyepiece instead of the imaging lens 66 and the detector 67, the reflecting surface 52a of the reflecting member 52 and the reflecting member 5 can be used.
The parallelism with the third reflecting surface 53a can be visually inspected.

Next, it is necessary to adjust the driving direction of the wafer stage 10 so that the scanning direction of the mask 4 matches the scanning direction of the wafer 8. In addition, matching the scanning direction of the mask stage 6 with the scanning direction of the wafer stage 10 can be easily achieved by using a conventional technique. For example, a reference mark on the wafer stage 10 is illuminated from inside the stage, and light from the reference mark is guided onto the mask stage 6 via the projection optical system 7 to form an image of the reference mark on the mask stage 6. Then, the driving direction of the wafer stage 10 is adjusted so that the mark on the mask stage 6 and the reference mark image overlap. Thus, the driving direction of the mask stage 6 and the wafer stage 1
The driving direction of the mask 4 and the scanning direction of the wafer 8 can be aligned with the projection optical system 7 by making the driving direction coincide with the reference axis AX3 of the holding member 43.

In the first embodiment described above, it is assumed that the first barrel 41 and the second barrel 42 have the same outer diameter, and the first surface 51a and the second surface 51b of the guide member 51 are connected to each other. They are formed in parallel. However, when the first barrel 41 and the second barrel 42 have different outer diameters, the first barrel 51 and the reference axis AX3 of the holding member 43 are parallel to each other so that the second surface 51b of the guide member 51 is parallel to the reference axis AX3 of the holding member 43.
An appropriate angle may be provided between the surface 51a and the second surface 51b.

In the first embodiment, the guide member 5
A reflecting member 52 having a reflecting surface 52a parallel to the second surface 51b is attached to the second surface 51b. However, the second surface 51b of the guide member 51 may be polished or the like, and the second surface 51b itself may be used as a reflection surface parallel to the reference axis AX3 of the holding member 43 instead of the reflection surface 52a. In any case, in the first embodiment, the positional relationship between the outer surface of the first barrel 41 and the outer surface of the second barrel 42 of the projection optical system 7 is used, and the first barrel 41 is used.
And the reflecting surface of the reflecting member directly or indirectly attached to the second barrel 42 has optical axes AX1 and AX2.
, That is, in parallel with the reference axis AX3 of the holding member 43.

In the first embodiment, the reflecting member 53 having a reflecting surface parallel to the driving direction is connected to the mask stage 6.
After the mask stage 6 is mounted thereon and the driving direction of the mask stage 6 is adjusted, the driving direction of the wafer stage 10 is adjusted so that the driving direction of the mask stage 6 matches the driving direction of the wafer 10. However, after a reflecting member having a reflecting surface parallel to the driving direction is mounted on the wafer stage 10 and the driving direction of the wafer stage 10 is adjusted, the driving direction of the mask stage 6 and the driving direction of the wafer 10 match. The driving direction of the mask stage 6 may be adjusted. Alternatively, a reflecting member having a reflecting surface parallel to the driving direction is mounted on each of the mask stage 6 and the wafer stage 10, and the adjustment of the driving direction of the mask stage 6 and the adjustment of the driving direction of the wafer stage 10 are separately performed. Good.

[Second Embodiment] FIG. 7 is a view for explaining a second embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system. The second embodiment is similar to the first embodiment described above. However, in the first embodiment, the reflecting member 52 is attached to the first barrel 41 and the second barrel 42 of the projection optical system 7, whereas in the second embodiment, the holding member 43 of the projection optical system 7 is attached.
Is provided with a reflection member 71. In the first embodiment, the reflecting surface 5 of the reflecting member 52 is utilized by utilizing the positional relationship between the outer surface of the first barrel 41 and the outer surface of the second barrel 42.
2a is set parallel to the reference axis AX3 of the holding member 43. On the other hand, in the second embodiment, the reflecting surface 71a of the reflecting member 71 is set parallel to the reference axis AX3 of the holding member 43 by utilizing the positional relationship between the two plane reflecting mirrors M2 and M3.

More specifically, the reflection surface 71a of the reflection member 71 attached to the holding member 43 is formed at the intersection of the extension surface of the reflection surface of the plane reflection mirror M2 and the extension surface of the reflection surface of the plane reflection mirror M3. It is adjusted so as to be orthogonal to this. Reflecting member 7
The adjustment of the first reflecting surface 71a is performed by using, for example, a three-dimensional measuring machine when assembling the holding member 43. Then, in the adjusted state, the reflecting surface 71a of the reflecting member 71 is set parallel to the reference axis AX3 of the holding member 43, that is, parallel to the plane including the optical axes AX1 and AX2. Therefore, in the second embodiment as well, similarly to the first embodiment, the driving direction of the mask stage 6 and the driving direction of the wafer stage 10 may be adjusted using the autocollimator 54.

As described above, in the first embodiment and the second embodiment, the reflecting member (52 or 71) having the reflecting surface parallel to the reference axis AX3 of the holding member 43 is attached to the projection optical system 7 in advance. Accordingly, the driving directions of the mask stage 6 and the wafer stage 10, and thus the mask 4 and the wafer 8
Can be aligned with respect to the projection optical system 7.

Third Embodiment FIG. 8 is a view for explaining a third embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system. FIG. 8 shows a state where the first barrel 41 and the second barrel 42 are partially assembled. That is, in the first barrel 41, the lens components L12 to L
13 is positioned and held at a predetermined position. Also, the second
In the barrel 42, the lens component L22 excluding the lens component L21
L211 are positioned and held at predetermined positions. Third
In this embodiment, in this state, the concave surface of the lens component L12 on the mask side is used as a reflection surface, and this lens component L12
And the optical axis AX1 of the first image forming optical system is measured, and the concave surface of the lens component L22 on the side of the plane reflecting mirror M3 is used as a reflecting surface, and the optical axis of the lens component L22 and the second image forming optical system are used. The optical axis AX2 of the system is measured.

FIG. 9 is a diagram schematically showing the configuration of a measuring device for measuring the optical axis of the lens component using the lens surface of the lens component as a reflection surface. The measuring device 80 in FIG. 9 has a wavelength of 830n as a light source for measurement.
A semiconductor laser light source 81 that supplies m light is provided. The light emitted from the semiconductor laser light source 81 passes through a beam splitter 82 and is once condensed by a condensing lens 83, and then reflected by a reflection surface 84 of a lens component to be measured.
Incident on. The light reflected from the reflecting surface 84 is transmitted to the condenser lens 8.
3 and is reflected by the beam splitter 82. The light reflected by the beam splitter 82 is condensed by a condenser lens 85
, Reaches the photoelectric conversion element 86. In this way, based on the output of the photoelectric conversion element 86, it is detected that the optical axis of the measuring device coincides with the optical axis of the lens component, and the optical axis of the lens component is detected. The axis (AX1 or AX2) can be measured.

The measuring device 80 shown in FIG. 9 also has a light source 87 for supplying visible light as a light source for observation. The light emitted from the light source 87 is incident on a half mirror 88 which is inclined with respect to the optical axis of the apparatus in the optical path between the light source 81 and the beam splitter 82. Half mirror 88
The light reflected by is transmitted through the beam splitter 82 and the half mirror 89, is condensed through the condenser lens 83, and illuminates the object 90 to be observed. Light reflected from the object 90 is reflected by the half mirror 89 via the condenser lens 83. The light reflected by the half mirror 89 reaches an imaging device 92 such as a CCD via a condenser lens 91, and forms an image of the surface of the object 90 on the imaging surface.

Referring again to FIG. 8, a pair of measuring devices 93 having basically the same configuration as the measuring device 80 shown in FIG.
And 94 are attached to the rail member 95. Here, the pair of measuring devices 93 and 94 are connected to the rail member 9.
5 is configured to be able to move linearly along the longitudinal axis direction. In the third embodiment, when assembling the first imaging optical system, the measuring device 93 measures the optical axis AX1 of the first imaging optical system, and the optical axis of the measuring device 93 and the optical axis of the first imaging optical system are measured. A
A state is formed in which X1 matches. When assembling the second imaging optical system, the measuring device 94 measures the optical axis AX2 of the second imaging optical system, and the optical axis of the measuring device 94 matches the optical axis AX2 of the second imaging optical system. A state is formed. In this state, the moving direction of the measuring device 93 that can move linearly along the longitudinal axis direction of the rail member 95 depends on the optical axis AX1 of the first imaging optical system and the optical axis AX2 of the second imaging optical system. This is in a plane including the reference axis AX3 of the holding member 43.

Next, as shown in FIG. 10, a plurality of marks 100 (for example, 20 mm
The test mask 101 on which three marks are formed at an interval of mm is mounted on the mask stage 6. At this time, the test mask 101 is placed on the mask stage 6 so that the driving direction of the mask stage 6 and the directions of the plurality of marks 100 match. Therefore, the mask stage 6 is slightly rotated so that the plurality of marks 100 on the test mask 101 can all be observed at the center of the observation field while moving the measuring device 93 along the longitudinal axis direction of the rail member 95. Accordingly, the driving direction of the mask stage 6 can be made to coincide with a plane including the optical axis AX1, the optical axis AX2, and the reference axis AX3, that is, the driving direction of the mask stage 6 can be aligned with the projection optical system 7. . As described above, in the third embodiment, since the optical member itself constituting the projection optical system 7 is used, an adjustment member such as a reflection member is added to the projection optical system 7 as in the first and second embodiments. No need to do.

[Fourth Embodiment] FIG. 11 is a view for explaining a fourth embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system. The fourth embodiment is similar to the third embodiment described above. However, in the third embodiment, each optical axis is measured using the concave surface of the lens component that actually constitutes the projection optical system 7.
The third embodiment basically differs from the third embodiment in that each optical axis is measured using a reflecting member having a reflecting concave surface having a desired curvature. Hereinafter, the fourth embodiment will be described focusing on the difference from the third embodiment.
An embodiment will be described.

In the fourth embodiment, while the first barrel 41 and the second barrel 42 are partially assembled, the first reflecting member having the reflecting concave surface 111 having a desired curvature is attached to the upper end of the first barrel 41. A second reflecting member having a reflecting concave surface 112 having a desired curvature is connected to the second barrel 42.
Attach to the upper end of Here, with the first reflecting member attached to the upper end of the first barrel 41, the reflecting concave surface 11 is provided.
The first reflecting member is configured so that the first optical axis and the central axis of the first barrel 41, that is, the optical axis AX1 of the first imaging optical system, coincide with each other. Further, the second reflecting member is connected to the second barrel 42.
The second reflecting member is configured such that the optical axis of the reflective concave surface 112 and the central axis of the second barrel 42, that is, the optical axis AX2 of the second imaging optical system, coincide with each other in a state where the optical axis AX2 is attached to the upper end of the optical disc.

Therefore, in the fourth embodiment, similarly to the third embodiment, the measuring device 93 utilizing the reflection concave surface 111 is used.
The optical axis AX1 of the first imaging optical system is measured by the
And the optical axis AX1 of the first image forming optical system is aligned. The measuring device 94 measures the optical axis AX2 of the second imaging optical system using the reflection concave surface 112, and determines that the optical axis AX2 of the second imaging optical system coincides with the optical axis of the second imaging optical system. Form. Then, while moving the measuring device 93 along the longitudinal axis direction of the rail member 95, the mask stage 6 is slightly rotated so that all the marks 100 on the test mask 101 can be observed at the center of the observation field. Thereby, the driving direction of the mask stage 6 can be aligned with the projection optical system 7.

As in the third embodiment, there is a case where there is no lens component having a reflecting surface having an appropriate curvature. in this case,
By using a reflecting member having a reflecting surface with a desired curvature as in the fourth embodiment, not only can the measurement of the optical axis be performed with high accuracy, but also the distance between the measuring device and the reflecting surface can be easily adjusted. be able to. As described above, in each embodiment, the scanning directions of the mask 4 and the wafer 8 are
The mask 4 and the wafer 8 are moved along the scanning direction in the aligned state, and the pattern image of the mask 4 is scanned and exposed on each exposure area of the wafer 8. Therefore, the exposure field of view can be set to the maximum within the range of the effective exposure area of the projection optical system 7, and good scanning exposure can be performed with high throughput under the set large exposure field of view.

The wafer that has undergone the scanning exposure step (photolithography step) of the present invention is subjected to a developing step,
The wafer process ends through an etching step of removing portions other than the developed resist, a resist removing step of removing unnecessary resist after the etching step, and the like.
Then, when the wafer process is completed, in the actual assembling process, dicing for cutting the wafer into chips for each printed circuit, bonding for providing wiring and the like to each chip, and packaging for packaging each chip Through these steps, a semiconductor device (LSI or the like) is finally manufactured as a device.

In the above description, an example in which a semiconductor element is manufactured by a photolithography process in a wafer process using a projection exposure apparatus has been described. Display element, thin film magnetic head, image sensor (CCD
Etc.) can be manufactured.

In each of the above embodiments, the present invention is applied to the scanning type exposure apparatus having the catadioptric projection optical system. However, the scanning exposure apparatus having the reflection projection optical system constituted by a plurality of reflecting members is used. The present invention can be applied to a mold exposure apparatus.

[0061]

As described above, according to the present invention, the scanning direction of the mask and the photosensitive substrate is aligned with the projection optical system, and the mask and the photosensitive substrate are aligned along the scanning direction in the aligned state. To scan and expose the pattern image of the mask to each exposure area of the photosensitive substrate. Therefore, the exposure field of view can be set to the maximum within the range of the effective exposure area of the projection optical system. As a result, good scanning exposure can be performed with high throughput under the set large exposure field of view.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing an overall configuration of a scanning exposure apparatus according to each embodiment of the present invention.

FIG. 2 is a diagram showing a lens configuration of the catadioptric projection optical system of FIG. 1;

FIG. 3 is a diagram showing a positional relationship between an effective exposure area and an exposure field on a wafer surface.

FIG. 4 is a diagram schematically showing a mechanical configuration of the catadioptric projection optical system of FIG. 1;

FIG. 5 is a diagram illustrating a first embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system.

6 is a diagram schematically showing an internal configuration of the autocollimator of FIG.

FIG. 7 is a diagram illustrating a second embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system.

FIG. 8 is a diagram illustrating a third embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system.

FIG. 9 uses a lens surface of a lens component as a reflection surface,
It is a figure which shows roughly the structure of the measuring device for measuring the optical axis of the lens component.

FIG. 10 is a view showing a state where a test mask on which a plurality of marks are formed in a straight line is placed on a mask stage.

FIG. 11 is a diagram illustrating a fourth embodiment in which the driving directions of the mask stage and the wafer stage are aligned with respect to the projection optical system.

[Explanation of symbols]

 Reference Signs List 1 light source 2 folding mirror 3 illumination optical system 4 mask 5 mask holder 6 mask stage 7 projection optical system 8 wafer 9 wafer holder 10 wafer stage 41 first barrel 42 second barrel 43 holding member 44 gantry 51 guide member 52, 53, 71 reflection Member 54 Autocollimator

Claims (4)

[Claims] An illumination system for illuminating a mask on which a pattern is formed, at least one reflecting surface, and a plurality of optical axes bent by the at least one reflecting surface, wherein a pattern image of the mask is provided. A projection optical system for projecting the photosensitive substrate on a photosensitive substrate, and a positioning unit for positioning a scanning direction of the mask and the photosensitive substrate with respect to the projection optical system. The mask and the photosensitive substrate are moved along the scanning direction in a state where the mask is aligned with the projection optical system, and the pattern image of the mask is scanned and exposed on each exposure region of the photosensitive substrate. Scanning exposure apparatus. 2. The projection optical system forms an effective exposure area having a predetermined shape on the photosensitive substrate, and forms a pattern of the mask under an exposure field set within the effective exposure area. An image is projected, and the alignment unit aligns a scanning direction of the mask and the photosensitive substrate along a specific axis defined depending on a shape of the effective exposure area. Item 2. A scanning exposure apparatus according to Item 1. 3. A scanning exposure of a pattern image of a mask on each exposure area of a photosensitive substrate using a projection optical system having at least one reflection surface and a plurality of optical axes bent by the at least one reflection surface. A scanning exposure method, wherein: a positioning step of positioning a scanning direction of the mask and the photosensitive substrate with respect to the projection optical system; and a scanning exposure of a pattern image of the mask on each exposure region of the photosensitive substrate. A scanning step of moving the mask and the photosensitive substrate along the scanning direction in a state where the mask is aligned with the projection optical system in the alignment step. Exposure method. 4. A scanning pattern exposure of a mask pattern image on each exposure area of a photosensitive substrate via a projection optical system having at least one reflection surface and a plurality of optical axes bent by the at least one reflection surface. In the method of manufacturing a scanning type exposure apparatus, a measuring step of measuring the plurality of optical axes when assembling the projection optical system is defined based on a positional relationship between the plurality of optical axes measured in the measuring step. An adjusting step of adjusting a driving direction of a mask stage holding and moving the mask or a substrate stage holding and moving the photosensitive substrate to move the mask or the photosensitive substrate along a specific axis; And a method of manufacturing a scanning type exposure apparatus.