JPWO2008078509A1 - Mask, mask stage, exposure apparatus, exposure method, and device manufacturing method - Google Patents

Abstract

A multi-scanning type exposure apparatus capable of performing good projection exposure using a plurality of projection optical units having a magnification while suppressing the influence of the self-weight deflection of a mask on image formation on a photosensitive substrate. An exposure apparatus according to the present invention for projecting and exposing a mask pattern onto a photosensitive substrate while moving the mask (M) and the photosensitive substrate (P) relative to the plurality of projection optical units (PL1 to PL11) along the scanning direction. The projection optical unit has a magnification larger than the same magnification. The mask stage includes a pair of support members that extend in the scanning direction and supports both ends of the mask, and one or more intermediate support members that extend between the pair of support members in the scanning direction and support the mask. .

Description

  The present invention relates to a mask, a mask stage, an exposure apparatus, an exposure method, and a device manufacturing method, and in particular, projects a mask pattern onto a photosensitive substrate while moving the mask and the photosensitive substrate relative to a plurality of projection optical units. The present invention relates to a mask stage suitable for a multi-scanning exposure apparatus.

  In recent years, liquid crystal display panels have been widely used as display devices such as televisions. The liquid crystal display panel is manufactured by patterning a transparent thin film electrode on a plate by a photolithography technique. A multi-scanning exposure apparatus is used as an apparatus for projecting and exposing a mask pattern onto a plate in this photolithography process.

  In a multi-scanning exposure apparatus, a mask pattern and projection exposure are performed on a plate while moving a mask and a plate (photosensitive substrate) relative to a projection optical system composed of a plurality of projection optical units (for example, Patent Document 1). See). In the conventional multi-scanning exposure apparatus described in Patent Document 1, the mask pattern is projected onto the plate at the same magnification.

JP 2001-337462 A

  Recently, as the liquid crystal display panel becomes larger, the mask tends to become larger. The mask is very expensive, and the cost increases due to the increase in size. Therefore, in order to avoid enlarging the mask, an enlargement system multi-scanning exposure apparatus using a projection optical unit having an enlargement magnification has been devised. In the magnifying system multi-scanning type exposure apparatus, the depth of focus on the mask side is smaller than that of a unity-magnification multi-scanning type exposure apparatus that uses a projection optical unit of the same magnification. The influence of “self-weight deflection” on image formation is also increased.

  In the prior art, since a relatively large focus shift occurs on the plate side due to the influence of the self-weight deflection of the mask, it is necessary to perform focus adjustment for each projection optical unit. In this case, an optical element for focus adjustment and its manufacturing process are required, and the manufacturing cost of the apparatus increases.

  The present invention has been made in view of the above-described problems, and it is preferable to use a plurality of projection optical units having an enlargement magnification while suppressing the influence of the self-weight deflection of the mask on the image formation on the photosensitive substrate. An object of the present invention is to provide a multi-scanning exposure apparatus and exposure method capable of performing projection exposure. Further, the present invention provides a device manufacturing method capable of manufacturing a good device with a large area by using a multi-scanning type exposure apparatus that performs good projection exposure using a plurality of projection optical units having a magnification. The purpose is to provide.

In order to solve the above-described problem, in the first aspect of the present invention, a plurality of exposure pattern areas arranged along a predetermined first direction and the first direction intersect between the plurality of exposure pattern areas. An unexposed area extending along the second direction,
The width of the non-exposure area is D, the dimension along the first direction from the first exposure pattern area to the last exposure pattern area is Mt, and the dimension along the first direction of the exposure pattern area is M. ₀ , when the number of non-exposed areas is N, the number of exposed pattern areas is k, and the minimum line width of the exposed pattern is a,
5.475 / a <D <{Mt− (k × M ₀ )} / N
A mask characterized by satisfying the following conditions is provided.

In the second aspect of the present invention, the plurality of exposure pattern areas arranged along a predetermined first direction and the second exposure pattern area extend along a second direction intersecting the first direction. Including non-exposed areas,
The width of the non-exposure area is D, the dimension along the first direction from the first exposure pattern area to the last exposure pattern area is Mt, and the dimension along the first direction of the exposure pattern area is M. ₀ , when the number of the non-exposure areas is N, the number of the exposure pattern areas is k, and the numerical aperture on the exposure pattern side of the projection optical unit that forms the image of the exposure pattern is NAm,
30 NAm <D <{Mt− (k × M ₀ )} / N
A mask characterized by satisfying the following conditions is provided.

In the third embodiment of the present invention, in the mask stage holding the mask,
A pair of support members extending in a predetermined direction to support both end portions of the mask, and one or a plurality of intermediate support members extending in the predetermined direction to support the mask between the pair of support members Have
The one or more intermediate support members are provided along a direction in which the mask is scanned during exposure.

In the fourth embodiment of the present invention, in the mask stage holding the mask,
A pair of support members extending in a predetermined direction to support both end portions of the mask, and one or a plurality of intermediate support members extending in the predetermined direction to support the mask between the pair of support members Have
The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit that projects the mask pattern is β, and the projection optical unit When the numerical aperture on the image side is NAp,
2S × (β × NAp) <W
A mask stage characterized by satisfying the above condition is provided.

In the fifth embodiment of the present invention, in the mask stage holding the mask,
A pair of support members extending in a predetermined direction to support both end portions of the mask, and one or a plurality of intermediate support members extending in the predetermined direction to support the mask between the pair of support members Have
The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit that projects the mask is β, and the image of the projection optical unit The numerical aperture on the side is NAp, the distance between the pair of support members in the predetermined direction is Mt, the number of the intermediate support members is N, and the illumination area formed on the mask surface along the predetermined direction When the number is k and the dimension of the illumination area along the predetermined direction is M ₀ ,
2S × (β × NAp) <W <{Mt− (k × M ₀ )} / N
A mask stage characterized by satisfying the above condition is provided.

  In a sixth aspect of the present invention, an illumination system that illuminates a mask, a third, fourth, or fifth form mask stage that holds the mask, and a plurality of projection optical units arranged along a predetermined direction An exposure apparatus for projecting and exposing a pattern of the mask onto the photosensitive substrate while relatively moving the mask and the photosensitive substrate along a scanning direction with respect to the plurality of projection optical units. provide.

According to a seventh aspect of the present invention, an illumination system that illuminates a mask, a mask stage that holds the mask, and a plurality of projection optical units arranged along a predetermined direction are provided. In the exposure apparatus for projecting and exposing the pattern of the mask onto the photosensitive substrate while relatively moving the mask and the photosensitive substrate along the scanning direction,
The projection optical unit has a magnification larger than equal magnification;
The mask stage extends in the scanning direction to support both ends of the mask, and one or more intermediate members that support the mask extending in the scanning direction between the pair of supporting members. An exposure apparatus having a support member is provided.

In the eighth embodiment of the present invention, an exposure step of exposing the photosensitive substrate with the pattern of the mask using the exposure apparatus of the seventh embodiment;
Developing the photosensitive substrate that has undergone the exposure step, and forming a mask layer having a shape corresponding to the pattern of the mask on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

In the ninth embodiment of the present invention, the mask and the photosensitive substrate are moved relative to each other along the scanning direction with respect to the plurality of projection optical units arranged along the predetermined direction, and the pattern of the mask is changed to the photosensitive substrate. In an exposure method for projection exposure to
As the projection optical unit, an optical system having a magnification larger than the same magnification is used,
Both ends of the mask are supported by a pair of support members extending in the scanning direction, and the mask is supported by one or more intermediate support members extending in the scanning direction between the pair of support members. An exposure method is provided.

In a tenth aspect of the present invention, an exposure step of exposing the photosensitive substrate with the pattern of the mask by the exposure method of the ninth aspect;
Developing the photosensitive substrate that has undergone the exposure step, and forming a mask layer having a shape corresponding to the pattern of the mask on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

  In the magnifying multi-scanning type exposure apparatus of the present invention, a mask stage extends in the scanning direction to support both ends of the mask, and the mask is supported by extending in the scanning direction between the pair of supporting members. One or more intermediate support members. As a result, the maximum amount of deflection due to the weight of the mask can be reduced as compared with the conventional technique in which both ends of the mask are simply supported.

  That is, in the exposure apparatus and the exposure method of the present invention, good projection exposure is performed using a plurality of projection optical units having magnifications while suppressing the influence of the self-weight deflection of the mask on the image formation on the photosensitive substrate. be able to. Moreover, a high-precision liquid crystal display element, for example, can be manufactured as a good device with a large area by good projection exposure using the exposure apparatus configured according to the present invention.

1 is a perspective view schematically showing an overall configuration of an exposure apparatus according to an embodiment of the present invention. It is a figure explaining the inconvenience of the mask holding mechanism by the conventional mask stage. It is a figure explaining the holding mechanism of the mask by a mask stage in the expansion type | system | group multi-scanning type exposure apparatus concerning this embodiment. It is a figure which shows typically a mode that each exposure area | region is formed on a plate so that it may mutually overlap along a scanning orthogonal direction. It is a figure explaining the prohibition zone area | region of a mask pattern being needed on both sides of the area | region corresponding to an intermediate | middle support member. It is a figure explaining the mask holding mechanism concerning the modification of this embodiment. 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

DESCRIPTION OF SYMBOLS 1 Light source 2 Elliptical mirror 3 Reflective mirror 4 Relay lens system 5 Fiber box 6 Fly eye integrator 7b Condenser lens system 11a, 11b Support member 12a, 12b Intermediate support member 13a, 13b Non-exposure area PA1-PA5 Exposure pattern area IR1-IR5 Lighting area (Teruno)
M Mask MS Mask stage PL1 to PL11 Projection optical unit P Plate

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view schematically showing the overall configuration of an exposure apparatus according to an embodiment of the present invention. In FIG. 1, the X axis is set in the plane of the mask M along the direction (scanning direction) in which the mask M on which a predetermined circuit pattern is formed and the resist-coated plate (photosensitive substrate) P are moved during exposure. The Y axis is set along the direction orthogonal to the X axis (scanning orthogonal direction), and the Z axis is set along the normal direction of the plate P.

  The exposure apparatus of this embodiment includes an illumination system for illuminating a mask M supported in parallel with the XY plane on a mask stage (not shown in FIG. 1) MS. The illumination system includes a light source 1 made of, for example, an ultrahigh pressure mercury lamp. The light source 1 is positioned at the first focal position of an elliptical mirror 2 having a reflecting surface made of a spheroid. Therefore, the illumination light beam emitted from the light source 1 forms a light source image at the second focal position of the elliptical mirror 2 via the reflecting mirror (plane mirror) 3. A shutter (not shown) is disposed at the second focal position.

  The divergent light beam from the light source image formed at the second focal position of the elliptical mirror 2 is imaged again via the relay lens system 4. In the vicinity of the pupil plane of the relay lens system 4, a wavelength selection filter (not shown) that transmits only light in a desired wavelength range, for example, light of i-line (365 nm) as exposure light is disposed. In the wavelength selection filter, for example, g-line (436 nm) light, h-line (405 nm), and i-line light can be simultaneously selected, or h-line light and i-line light are simultaneously selected. You can also

  In the vicinity of the position where the light source image is formed by the relay lens system 4, the incident side light guide surface of the fiber box 5 is positioned. The light beam incident on the light guide of the fiber box 5 propagates through the inside thereof and then exits from the eleven exit-side light guides. Thus, the fiber box 5 has the same number of incident ends as the number of light sources 1 (one in FIG. 1) and the same number as the number of projection optical units (11 in FIG. 1) constituting the projection optical system. And an injection end.

  A divergent light beam emitted from one typical emission side light guide of the fiber box 5 is converted into a substantially parallel light beam by a collimator lens 7 a and then enters a fly-eye integrator (optical integrator) 6. The fly-eye integrator 6 is configured, for example, by arranging a large number of positive lens elements vertically and horizontally and densely so that the central axis extends along the optical axis AX. Therefore, the light beam incident on the fly-eye integrator 6 is divided into wavefronts by a large number of lens elements, and a secondary light source (substantially) consisting of the same number of light source images as the number of lens elements on the rear focal plane (that is, near the exit surface). A typical surface light source).

  The light beam from the secondary light source is limited by an aperture stop (not shown) disposed in the vicinity of the rear focal plane of the fly-eye integrator 6 and then enters the condenser lens system 7b. The aperture stop is disposed at a position optically conjugate with the pupil plane of the corresponding projection optical unit, and has a variable aperture for defining the range of the secondary light source that contributes to illumination. The aperture stop changes the aperture diameter of the variable aperture, thereby determining the σ value that determines the illumination condition (secondary on the pupil plane relative to the aperture diameter of the pupil plane of each projection optical unit constituting the projection optical system) The ratio of the diameter of the light source image) is set to a desired value.

  The light flux through the condenser lens system 7b illuminates the mask M on which a predetermined transfer pattern is formed in a superimposed manner. Similarly, divergent light beams emitted from the other light guides on the exit side of the fiber box 5 are also superimposed on the mask M via the collimating lens 7a, the fly-eye integrator 6, the aperture stop, and the condenser lens system 7b. Illuminate. In other words, the illumination system illuminates a plurality (11 in total in FIG. 1) of predetermined shapes arranged in the Y direction on the mask M. Here, although a trapezoidal illumination area is schematically shown in FIG. 1, a hexagonal illumination area (an illumination field) is formed in the present embodiment as will be described later.

  In the above-described example, in the illumination system, the illumination light from one light source 1 is equally divided into 11 illumination lights by the fiber box 5, but is limited to the number of light sources and the number of projection optical units. Without limitation, various modifications are possible. That is, if necessary, two or more light sources are provided, and the illumination light from these two or more light sources is equally divided into a required number (the number of projection optical units) of illumination light through a light guide with good randomness. You can also In this case, the fiber box 5 has the same number of incident ends as the number of light sources, and has the same number of exit ends as the number of projection optical units.

  The light from each illumination area on the mask M is a projection optical system comprising a plurality (11 in total in FIG. 1) of projection optical units PL1 to PL11 arranged along the Y direction so as to correspond to each illumination area. Is incident on. Here, the configurations of the projection optical units PL1 to PL11 are the same. Each of the projection optical units PL1 to PL11 is an optical system that is almost telecentric on both sides (the mask M side and the plate P side).

  In FIG. 1, the reference symbols PL3, PL5, PL7, PL9, and PL11 are not shown for clarity. FIG. 1 shows an example in which a catadioptric optical system is used as each projection optical unit. However, the present invention is not limited to this, and various types of optical systems having a magnification larger than the same magnification, that is, an enlargement magnification, Can be used. That is, as each projection optical unit, a once-imaging optical system having an enlargement magnification, a twice-imaging optical system having an enlargement magnification, or the like can be used.

  The light passing through the projection optical system composed of the plurality of projection optical units PL1 to PL11 forms a mask pattern image on the plate P supported in parallel with the XY plane on a plate stage (not shown). As described above, since each projection optical unit PL1 to PL11 is configured as an enlargement system, a plurality of hexagonal exposures arranged in the Y direction so as to correspond to each illumination area on the plate P which is a photosensitive substrate. An enlarged image of the mask pattern is formed in the region.

  The mask stage is provided with a scanning drive system (not shown) having a long stroke for moving the stage along the X direction which is the scanning direction. In addition, a pair of alignment drive systems (not shown) are provided for moving the mask stage by a minute amount along the Y direction, which is the orthogonal direction of scanning, and for rotating the mask stage by a minute amount around the Z axis. The position coordinate of the mask stage is measured by a laser interferometer (not shown) using a movable mirror and the position is controlled.

  A similar drive system is also provided for the plate stage. That is, a scanning drive system (not shown) having a long stroke for moving the plate stage along the X direction, which is the scanning direction, and moving the plate stage by a minute amount along the Y direction, which is the orthogonal direction of scanning. A pair of alignment drive systems (not shown) for rotating a minute amount around the shaft is provided. The position coordinate of the plate stage is measured and controlled by a laser interferometer PIF using a moving mirror.

  A pair of alignment systems (not shown) are arranged above the mask M as means for relatively aligning the mask M and the plate P along the XY plane. As the alignment system, for example, an alignment system in which a relative position between a mask alignment mark formed on the mask M and a plate alignment mark formed on the plate P is obtained by image processing can be used. Further, the plate stage is provided with an illuminance sensor IS for measuring the illuminance on the image plane of each of the projection optical units PL1 to PL11.

  In the magnifying system multi-scanning type exposure apparatus of the present embodiment, a mask is applied to the projection optical system composed of a plurality of projection optical units PL1 to PL11 by the action of the scanning drive system on the mask stage side and the scanning drive system on the plate stage side. By moving the M and the plate P along the X direction, the entire pattern area on the mask P is transferred (scanned exposure) to the entire exposure area on the plate P.

  Here, a mask holding mechanism using a conventional mask stage will be described with reference to FIG. As shown in FIG. 2A, the conventional mask stage 20 has a frame structure in which one rectangular opening is formed at the center. The mask M is simply supported at both ends on the slightly outer side of the pattern area PA by a pair of support members 21a and 21b extending in the X direction which is the scanning direction. In this case, the mask M is curved by its own weight as shown in FIG. 2B along the Y direction that is the scanning orthogonal direction.

At this time, the maximum deflection amount δ ₁ due to the weight of the mask M is expressed by the following equation (1). In equation (1), ω is the mass per unit length along the Y direction of the mask M (kg / mm), and L is the distance between the pair of support members 21a and 21b along the Y direction (mm). It is. E is the Young's modulus (kgf / mm ² ) of the material forming the mask M, and I is the second-order moment (mm ⁴ ) of the mask M with respect to bending in the Y direction.
δ ₁ = 5 × ωL ⁴ / (384 × EI) (1)

In the conventional equal magnification multi-scanning type exposure apparatus, the maximum deflection amount δ ₁ due to the weight of the mask is about 20 times the focal depth of the projection optical unit allowed on the mask side. In addition, it was necessary to adjust the focus on the plate. Regarding the focus adjustment of the projection optical unit, for example, JP-A-2005-340605, JP-A-2005-331694, JP-A-2001-337463, and the like can be referred to.

Prior to the description of the mask holding mechanism in the present embodiment, the difference in the depth of focus on the mask side of the projection optical unit between the enlargement system multi-scanning type and the equal magnification system multi-scanning type will be described below. The magnification β of the projection optical unit of the magnifying system in the present embodiment is 2.5, and the numerical aperture NAp on the plate side (image side) of the projection optical unit is 0.085 in both the magnifying system and the equal magnification system. Yes, when the light wavelength λ is 0.365 μm in both the magnification system and the unit magnification system, the numerical aperture NAm on the mask side (object side) of the projection optical unit in each system, the DOFm (= λ / NAm ² ) and the like are as shown in the following table (1).

Table (1)
β NAp NAm DOFm
Equal magnification system 1 0.085 0.085 50 μm
Magnification system 2.5 0.085 0.2125 8 μm

As shown in Table (1), when the magnification wavelength and the resolution on the plate side are unified and the enlargement system and the equal magnification system are compared, the focal depth DOFm on the mask side in the enlargement system is 1/6 that of the equal magnification system. .25 (= 1 / 2.5 ² ) times. That is, in the magnifying system multi-scanning type exposure apparatus, the depth of focus DOFm on the mask side becomes smaller in accordance with the square of the magnification magnifying β of the projection optical unit, compared to the same-size system multi-scanning type exposure apparatus. It can be seen that the self-weight deflection greatly affects the image formation on the plate.

  Next, with reference to FIG. 3, the mask holding mechanism by the mask stage in the enlargement multi-scanning exposure apparatus according to the present embodiment will be described. As shown in FIG. 3A, the mask stage MS of the present embodiment has a frame structure that forms three rectangular openings arranged in the Y direction. The mask M is supported by a pair of support members 11a and 11b extending in the X direction, which is the scanning direction, and a pair of intermediate support members 12a and 12b extending in the X direction between the pair of support members 11a and 11b. The

  Hereinafter, in order to simplify the description, it is assumed that five hexagonal illumination areas are formed on the mask M corresponding to the five projection optical units. In this case, the mask M is arranged in the X direction between the five exposure pattern areas PA1 to PA5 arranged along the Y direction that is the scanning orthogonal direction, and between the second exposure pattern area PA2 and the third exposure pattern area PA3. The first non-exposure area 13a that is elongated and the second non-exposure area 13b that is elongated in the X direction between the third exposure pattern area PA3 and the fourth exposure pattern area PA4.

  Here, the width dimensions along the Y direction of the exposure pattern areas PA1 to PA5 are equal to each other, and the hexagonal illumination areas IR1 to IR5 formed over the entire width of the exposure pattern areas PA1 to PA5 have the same shape and Have the same size. Thus, the mask M is supported by the support member 11a at the slightly outer end of the first exposure pattern area PA1, and supported by the support member 11b at the slightly outer end of the fifth exposure pattern area PA5. It is supported by the intermediate support member 12a at the center of the first non-exposure region 13a and supported by the intermediate support member 12b at the center of the second non-exposure region 13b.

  Thus, unlike the case of the unit magnification system, it is not necessary to form the illumination areas IR1 to IR5 so as to partially overlap each other along the Y direction. Accordingly, they can be separated from each other. That is, the exposure pattern areas PA1 to PA5 corresponding to the illumination areas IR1 to IR5 do not need to be arranged adjacent to each other, and a non-exposure area is provided between two arbitrary exposure pattern areas, and the mask stage MS is intermediately supported. A member can be provided.

  However, on the plate P, as shown in FIG. 4, the hexagonal exposure areas ER1 to ER5 partially overlap each other along the Y direction (scanning orthogonal direction) corresponding to the illumination areas IR1 to IR5. To be formed. This is because, for example, a parallel plane plate (not shown) as an image shifter is provided in the optical path immediately after the mask M or in the optical path immediately before the plate P. A plane parallel plate as an image shifter is configured such that its parallel plane rotates around a predetermined axis. When the plane-parallel plate is rotated around a predetermined axis, the images of the illumination areas IR1 to IR5 formed on the plate P are moved to desired positions (image shift) on the XY plane.

  In FIG. 3B, a distance along the Y direction between the pair of support members 11a and 11b is represented by L / β. This is to make the dimension along the Y direction of the entire exposure region on the plate the same in the enlargement system and the equal magnification system. Then, the maximum distance Lm of the two support members adjacent to each other in the Y direction, that is, the distance in the Y direction between the support member 11a and the intermediate support member 12a (or the support member 11b and the intermediate support member 12b). Lm = L / (β × n) using the parameter n related to the maximum distance Lm.

In the mask holding mechanism of the present embodiment, the mask M is bent by its own weight as shown in FIG. 3B along the Y direction which is the scanning orthogonal direction. In this case, the maximum deflection amount [delta] _beta due to the weight of the mask M is approximated by the following equation (2). To be more exact, the maximum amount of deflection [delta] _beta due to the weight of the mask M is smaller than the value expressed by the right side of the equation (2).
δ _β = δ ₁ / (β ⁴ × n ⁴ ) (2)

Thus, in the enlarged system multi scanning type exposure apparatus according to this embodiment, the maximum deflection amount [delta] _beta due to the weight of the mask M accommodated in the mask side of the focal depth (= λ / NAm ²⁾ within, for each projection optical unit In order to make the focus adjustment unnecessary, it is necessary to satisfy the following conditional expression (3) and by extension, conditional expression (4).
δ _β = δ ₁ / (β ⁴ × n ⁴ ) <λ / NAm ² = λ / (NAp ² × β ² ) (3)
(1 / λ) × δ ₁ × NAp ² <β ² × n ⁴ (4)

Thus, when the light wavelength λ, the maximum amount of deflection δ ₁ when the intermediate support members 12a and 12b are not interposed, and the image-side numerical aperture NAp of the projection optical unit are known, the magnification β of each projection optical unit When the value is determined, the condition of the parameter n that satisfies the conditional expression (4) is obtained. As a result, a condition to be satisfied by the maximum distance Lm is obtained, and as a result, the number and arrangement of intermediate support members necessary to eliminate the focus adjustment for each projection optical unit can be obtained.

Specifically, when the light wavelength λ is 0.365 μm, the image-side numerical aperture NAp of the projection optical unit is 0.085, and the magnification β of the projection optical unit is 2.5, it is standard. Since the maximum deflection amount δ ₁ of the mask in such an apparatus is about 0.518 mm, the condition of the parameter n satisfying the conditional expression (4) is as shown in the following expression (5).
1.658 <n ⁴ (5)

That is, in the case of the present embodiment, if 1.14 <n, the conditional expression (5) is satisfied. In the mask holding mechanism shown in FIG. 3, since n≈2.5, the conditional expression (5) is satisfied. Therefore, the maximum amount of deflection [delta] _beta fits within the depth of focus of the mask side by its own weight of the mask M, and thus the focus adjustment of each projection optical unit has become unnecessary. Even if one of the two intermediate support members 12a and 12b is removed, conditional expression (5) is satisfied because n≈1.67. Therefore, also in this case, the maximum deflection amount [delta] _beta mask M fits within the depth of focus on the mask side, is unnecessary focus adjustment of each projection optical unit.

As described above, in the enlarged multi-scanning exposure apparatus of the present embodiment, the mask stage MS extends in the scanning direction (X direction) and supports a pair of support members 11a and 11b that support both ends of the mask M, and this Intermediate support members 12a and 12b that support the mask M by extending in the scanning direction between the pair of support members 11a and 11b are provided. As a result, as compared with the conventional technique of simply supporting both ends of the mask M, it is possible to reduce the maximum amount of deflection [delta] _beta due to the weight of the mask M.

That is, in the exposure apparatus of the present embodiment, it is possible to perform good projection exposure using a plurality of projection optical units having a magnification while suppressing the influence of the self-weight deflection of the mask M on the image formation on the plate P. it can. Further, in the exposure apparatus of the present embodiment, for example, the intermediate support member 12a so as to satisfy the conditional expression (4), since the attaching a 12b, the mask side of the projection optical unit the maximum deflection amount [delta] _beta mask M It can be kept within the depth of focus, and focus adjustment for each projection optical unit is unnecessary.

  Incidentally, in the mask holding mechanism shown in FIG. 3, for example, the light beam diffracted in the third exposure pattern area PA3 is preferably imaged on the plate P without being blocked by the intermediate support members 12a and 12b. In order to prevent the image forming light beam from the exposure pattern region from being blocked by the intermediate support members 12a and 12b, as shown in FIG. 5, at least a width of Dm on both sides of the region corresponding to the intermediate support members 12a and 12b. A forbidden band area of the mask pattern is required.

That is, the Y direction (scanning orthogonal direction) between the intermediate support members 12a and 12b and the pattern area of the mask M (corresponding to the second exposure pattern area PA2, the third exposure pattern area PA3, and the fourth exposure pattern area PA4 in FIG. 3). It is preferable that the distance Dm along the line satisfies the following conditional expression (6). In Formula (6), S is the height dimension of the cross section of the intermediate support members 12a and 12b. As described above, β is the magnitude of the magnification of the projection optical unit, and NAp is the numerical aperture on the image side of the projection optical unit.
S × (β × NAp) <Dm (6)

  As an example of numerical values, assuming that β = 2.5, NAp = 0.085, and S = 20 (mm), the condition of 4.25 (mm) <Dm is obtained. That is, in this numerical example, in order to prevent the imaging light beam from the exposure pattern area from being blocked by the intermediate support members 12a and 12b, the width dimension Dm along the Y direction of the forbidden band area of the mask pattern is set to 4. It can be seen that it must be set larger than 25 (mm).

  Next, the required width of the cross section of the intermediate support member will be considered with reference to the modification of FIG. The modification of FIG. 6 is similar to the mask holding mechanism of FIG. 3, but is different from FIG. 3 in that the installation of the first intermediate support member 12a is omitted. As a result, in the mask M, the non-exposure area between the second exposure pattern area PA2 and the third exposure pattern area PA3 is omitted, and the first exposure pattern area PA1 to the third exposure pattern area PA3 are arranged adjacent to each other. Yes.

At this time, it is preferable that the width dimension W of the portion in contact with the mask of the cross section of the intermediate support member 12b satisfies the following conditional expression (7). In conditional expression (7), S is the height dimension of the cross section of the intermediate support member 12b, and Mt is the distance between the pair of support members 11a and 11b in the Y direction, or from the first first exposure pattern area PA1. This is the dimension along the Y direction up to the final fifth exposure pattern area PA5. K is the number of illumination areas (illumination fields) formed on the mask surface along the Y direction, or the number of projection optical units, and M ₀ is the dimension along the Y direction of each illumination area on the mask M. N is the number of intermediate support members (1 in the case of FIG. 6). As described above, β is the magnitude of the magnification of the projection optical unit, and NAp is the numerical aperture on the image side of the projection optical unit.
2S × (β × NAp) <W <{Mt− (k × M ₀ )} / N (7)

The lower limit value of the conditional expression (7) is that, as shown in FIG. 6, the light beam having the required numerical aperture (= NAm = NAp × β) on the mask side is not shielded by the intermediate support member 12b having the cross-sectional height dimension S. This corresponds to the width dimension of the cross section of the intermediate support member 12b which is necessary at the minimum. The upper limit value of conditional expression (7) is a limit value obtained from the Y-direction dimension of each exposure pattern area (Y-direction dimension of each illumination area) and the Y-direction dimension of the entire pattern area of the mask M. In the numerical example according to the modification of FIG. 6, β = 2.5, NAp = 0.085, k = 5, Mt = 535.2 (mm), M ₀ = 93.04 (mm), S = 20 ( mm) and N = 1, the following conditional expression (8) corresponding to the conditional expression (7) is obtained with respect to the width dimension W of the portion of the intermediate support member 12b that is in contact with the mask.
8.5 (mm) <W <70 (mm) (8)

  Therefore, in an actual design example, if the width dimension W of the cross section of the intermediate support member 12b is set to 10 (mm) and a holding area of about 30 mm is secured at both end portions of the mask M, the mask M is stable. It is possible to hold it.

Next, the width of the non-exposed area on the mask will be considered with reference to the modification of FIG. The width D (not shown in FIG. 6 for the sake of clarity) of the non-exposed region 13b on the mask M preferably satisfies the following conditional expression (9). In conditional expression (9), S is the height dimension of the cross section of the intermediate support member 12b, NAm is the numerical aperture on the pattern side (mask side) of the projection optical unit, and Mt is the first first exposure pattern area PA1. To the last fifth exposure pattern area PA5 along the Y direction, k is the number of exposure pattern areas on the mask M, and M ₀ is along the Y direction of each exposure pattern area on the mask M. N is the number of non-exposed areas (1 in the case of FIG. 6).
2S × NAm <D <{Mt− (k × M ₀ )} / N (9)

As shown in FIG. 6, the lower limit value of the conditional expression (9) is minimum so that the light beam having the necessary numerical aperture (= NAm) on the mask side is not shielded by the intermediate support member 12b having a cross sectional height of S. This corresponds to the required width dimension of the non-exposure region 13b. The upper limit value of conditional expression (9) is a limit value obtained from the Y-direction dimension of each exposure pattern area (Y-direction dimension of each illumination area) and the Y-direction dimension of the entire pattern area of the mask M. Further, the conditional expression (9) can be rewritten as shown in the following conditional expression (10) in consideration of the resolution Rm on the mask side.
2S × {(k1 × λ) / Rm} <D <{Mt− (k × M ₀ )} / N (10)

In conditional expression (10), k1 is a constant determined by the characteristics of the resist, and λ is the exposure wavelength. In a typical numerical example, k1 = 0.5 and λ = 0.365 (μm). The resolution Rm on the mask side is considered to be the minimum line width a of the pattern drawn on the mask M. Therefore, the conditional expression (10) can be rewritten as shown in the following conditional expression (11).
2S × {0.1825 / a} <D <{Mt− (k × M ₀ )} / N (11)

Further, when alumina ceramic or the like is used as a material for forming the intermediate support member, the height dimension S of the cross section of the intermediate support member is set to keep the maximum deflection amount δ _β due to the weight of the mask M within the focal depth on the mask side. It was calculated from calculation that it should be about 15 (mm). In this calculation, it was assumed that the specific gravity of the alumina ceramic was 4 (g / cm ³ ), the Young's modulus E of the alumina ceramic was 350 (GPa), and the length of the intermediate support member in the scanning direction was 488 (mm). As a result, the conditional expression (11) can be rewritten as shown in the following conditional expression (12) and as shown in the conditional expression (12 ′).
30 × {0.1825 / a} <D <{Mt− (k × M ₀ )} / N (12)
5.475 / a <D <{Mt− (k × M ₀ )} / N (12 ′)

In a more specific numerical example, when a = 1.37, k = 5, Mt = 535.2 (mm), M ₀ = 93.04 (mm), and N = 1, the width D of the non-exposed region 13b. In relation to the conditional expression (12 ′), the following conditional expression (13) is obtained.
4 (mm) <D <70 (mm) (13)

  Therefore, for example, when the cross section of the intermediate support member 12b is rectangular, the width D of the non-exposure region 13b = 18.5 (mm), the width dimension W of the cross section of the intermediate support member 12b = 10 (mm), the intermediate support If the height dimension S = 15 (mm) of the cross section of the member 12b is set, a holding area of about 25.75 mm can be secured at both end portions of the mask M without blocking a light beam having a required numerical aperture (NA). Thus, the mask M can be stably held. When the cross section of the intermediate support member 12b is triangular, and the mask is held on the triangular bottom surface side, the width D of the non-exposure region 13b is 10 (mm), and the portion of the cross section of the intermediate support member 12b is in contact with the mask. If the width dimension W is set to 10 (mm) and the height dimension S of the cross section of the intermediate support member 12b is set to 15 (mm), both end portions of the mask M can be obtained without blocking the light flux having a necessary numerical aperture (NA). In addition, if a holding area of about 30 mm is secured for each, the mask M can be stably held.

Further, when alumina ceramic or the like is used as a material for forming the intermediate support member, in order to keep the maximum deflection amount δ _β due to the weight of the mask M within the focal depth on the mask side, as described above, the height of the cross section of the intermediate support member is high. The dimension S may be about 15 (mm). As a result, conditional expression (9) can be rewritten as shown in the following conditional expression (14), and conditional expression (14) can be used instead of conditional expression (12 ′).
30 NAm <D <{Mt− (k × M ₀ )} / N (14)

  In the above description, an example in which an intermediate support member having a rectangular cross section is used is shown, but the present invention is not limited to this, and various modifications can be made to the cross sectional shape of the intermediate support member. Specifically, the cross-sectional shape of the intermediate support member is not limited to a rectangular shape, and may be a triangle, a trapezoid, an ellipse, a circle, or the like.

  In the above description, the mask is placed on the intermediate support member. However, the present invention is not limited to this, and various forms of support of the mask by the intermediate support member are possible. Specifically, the unexposed area of the mask can be skewered with an intermediate support member so as to suppress the self-weight deflection of the mask, as in the case of eel burning.

  The exposure apparatus according to the present embodiment is assembled by electrically, mechanically, or optically coupling the optical members and the stages in the present embodiment shown in FIG. 1 so as to achieve the functions described above. be able to. Then, the mask is illuminated by the illumination system (illumination process), and the transfer pattern formed on the mask is scanned and exposed on the photosensitive substrate using the projection optical system including the projection optical units PL1 to PL11 (exposure process). Thus, a device (semiconductor element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. FIG. 7 shows 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 shown in FIG. This will be described with reference to a flowchart.

  First, in step 301 of FIG. 7, 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. 8, in the pattern formation process 401, a so-called photolithography process is performed in which the exposure pattern of the present embodiment is used to transfer and expose the mask pattern onto a photosensitive substrate (such as a glass substrate coated with a resist). By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate 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.

Claims (23)

A plurality of exposure pattern regions arranged along a predetermined first direction; and a non-exposure region extending along a second direction intersecting the first direction between the plurality of exposure pattern regions;
The width of the non-exposure area is D, the dimension along the first direction from the first exposure pattern area to the last exposure pattern area is Mt, and the dimension along the first direction of the exposure pattern area is M. ₀ , when the number of non-exposed areas is N, the number of exposed pattern areas is k, and the minimum line width of the exposed pattern is a,
5.475 / a <D <{Mt− (k × M ₀ )} / N
A mask characterized by satisfying the above conditions. When used in combination with a projection optical unit that forms an image of the exposure pattern, and the numerical aperture on the exposure pattern side of the projection optical unit is NAm,
30 NAm <D <{Mt− (k × M ₀ )} / N
The mask according to claim 1, wherein the following condition is satisfied. A plurality of exposure pattern regions arranged along a predetermined first direction; and a non-exposure region extending along a second direction intersecting the first direction between the plurality of exposure pattern regions;
The width of the non-exposure area is D, the dimension along the first direction from the first exposure pattern area to the last exposure pattern area is Mt, and the dimension along the first direction of the exposure pattern area is M. ₀ , when the number of the non-exposure areas is N, the number of the exposure pattern areas is k, and the numerical aperture on the exposure pattern side of the projection optical unit that forms the image of the exposure pattern is NAm,
30 NAm <D <{Mt− (k × M ₀ )} / N
A mask characterized by satisfying the above conditions. The plurality of exposure pattern areas include a first exposure pattern area and a second exposure pattern area, and a part of an image of the first exposure pattern area formed by the first projection optical unit of the projection optical units. And part of the image of the second projection optical unit formed by a second projection optical unit different from the first projection optical unit among the projection optical units is formed so as to overlap each other. The mask according to claim 2, wherein the mask is a mask. In the mask stage that holds the mask,
A pair of support members extending in a predetermined direction to support both end portions of the mask, and one or a plurality of intermediate support members extending in the predetermined direction to support the mask between the pair of support members Have
The one or more intermediate support members are provided along a direction in which the mask is scanned during exposure. Used in combination with a projection optical unit that projects the pattern of the mask,
The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit is β, and the numerical aperture on the image side of the projection optical unit Is NAp,
2S × (β × NAp) <W
The mask stage according to claim 5, wherein the following condition is satisfied. Used in combination with a projection optical unit that projects the pattern of the mask,
The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit is β, and the numerical aperture on the image side of the projection optical unit Is NAp, the distance between the pair of support members in the predetermined direction is Mt, the number of the intermediate support members is N, and the number of illumination regions formed on the mask surface along the predetermined direction is k. When the dimension of the illumination area along the predetermined direction is M ₀ ,
2S × (β × NAp) <W <{Mt− (k × M ₀ )} / N
The mask stage according to claim 5 or 6, wherein the following condition is satisfied. In the mask stage that holds the mask,
A pair of support members extending in a predetermined direction to support both end portions of the mask, and one or a plurality of intermediate support members extending in the predetermined direction to support the mask between the pair of support members Have
The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit that projects the mask pattern is β, and the projection optical unit When the numerical aperture on the image side is NAp,
2S × (β × NAp) <W
A mask stage characterized by satisfying the above conditions. In the mask stage that holds the mask,
A pair of support members extending in a predetermined direction to support both end portions of the mask, and one or a plurality of intermediate support members extending in the predetermined direction to support the mask between the pair of support members Have
The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit that projects the mask pattern is β, and the projection optical unit NAp is the numerical aperture on the image side, Mt is the distance between the pair of support members in the predetermined direction, N is the number of intermediate support members, and illumination is formed on the mask surface along the predetermined direction. When the number of areas is k and the dimension of the illumination area along the predetermined direction is M ₀ ,
2S × (β × NAp) <W <{Mt− (k × M ₀ )} / N
A mask stage characterized by satisfying the above conditions. The mask stage according to claim 8 or 9, wherein the one or more intermediate support members are provided along a direction in which the mask is scanned during exposure. The pattern of the mask includes a first exposure pattern region and a second exposure pattern region, and a part of the image of the first exposure pattern region formed by the first projection optical unit of the projection optical unit; A part of the image of the second projection optical unit formed by a second projection optical unit different from the first projection optical unit among the projection optical units is formed so as to overlap each other. The mask stage according to any one of claims 6 to 10. An illumination system that illuminates a mask, the mask stage according to any one of claims 5 to 11 that holds the mask, and a plurality of projection optical units arranged along a predetermined direction, the plurality of projection optical units. An exposure apparatus for projecting and exposing a pattern of the mask onto the photosensitive substrate while relatively moving the mask and the photosensitive substrate along a scanning direction with respect to a projection optical unit. An illumination system for illuminating a mask, a mask stage for holding the mask, and a plurality of projection optical units arranged along a predetermined direction, and the mask and the photosensitive substrate are disposed on the plurality of projection optical units. In an exposure apparatus that projects and exposes the pattern of the mask onto the photosensitive substrate while relatively moving along a scanning direction,
The projection optical unit has a magnification larger than equal magnification;
The mask stage extends in the scanning direction to support both ends of the mask, and one or more intermediate members that support the mask extending in the scanning direction between the pair of supporting members. An exposure apparatus comprising a support member. The width of the cross section of the intermediate support member is W, the height of the cross section of the intermediate support member is S, the magnification of the projection optical unit is β, and the numerical aperture on the image side of the projection optical unit Is NAp,
2S × (β × NAp) <W
The exposure apparatus according to claim 13, wherein the following condition is satisfied. The distance between the pair of support members in the predetermined direction is Mt, the number of the intermediate support members is N, and the illumination system is formed on the mask so as to correspond to each of the plurality of projection optical units. When the dimension of each illumination field along the predetermined direction is M ₀ and the number of the plurality of projection optical units is k,
2S × (β × NAp) <W <{Mt− (k × M ₀ )} / N
The exposure apparatus according to claim 14, wherein the following condition is satisfied. The mask pattern includes a first exposure pattern region and a second exposure pattern region, and a part of an image of the first exposure pattern region formed by the first projection optical unit of the plurality of projection optical units. And a part of the image of the second projection optical unit formed by a second projection optical unit different from the first projection optical unit among the plurality of projection optical units is formed so as to overlap each other. The exposure apparatus according to any one of claims 12 to 15, wherein An exposure step of exposing the photosensitive substrate with the pattern of the mask using the exposure apparatus according to any one of claims 12 to 16.
Developing the photosensitive substrate that has undergone the exposure step, and forming a mask layer having a shape corresponding to the pattern of the mask on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer. In the exposure method of projecting and exposing the pattern of the mask onto the photosensitive substrate while relatively moving the mask and the photosensitive substrate along the scanning direction with respect to the plurality of projection optical units arranged along a predetermined direction,
As the projection optical unit, an optical system having a magnification larger than the same magnification is used,
Both ends of the mask are supported by a pair of support members extending in the scanning direction, and the mask is supported by one or more intermediate support members extending in the scanning direction between the pair of support members. Exposure method. 19. The exposure according to claim 18, wherein the one or more intermediate support members are arranged so that a maximum deflection amount due to the weight of the mask is smaller than a depth of focus on the mask side of the projection optical unit. Method. The maximum distance Lm of the two support members adjacent to each other in the predetermined direction is defined as Lm, the magnification of the projection optical unit is β, and the distance between the pair of support members in the predetermined direction is defined as β. L / β, a parameter relating to the maximum distance Lm, n, a light wavelength λ, and the weight of the mask supported by the pair of support members when the one or more intermediate support members are not interposed When the maximum deflection amount is δ ₁ and the numerical aperture on the image side of the projection optical unit is NAp,
Lm = L / (β × n)
(1 / λ) × δ ₁ × NAp ² <β ² × n ⁴
The exposure method according to claim 18 or 19, wherein the maximum interval Lm is set so as to satisfy the following condition. When the height dimension of the cross section of the intermediate support member is S, the magnification of the projection optical unit is β, and the numerical aperture on the image side of the projection optical unit is NAp, the intermediate support member and the mask The distance Dm along the predetermined direction with the pattern region of
S × (β × NAp) <Dm
21. The exposure method according to claim 18, wherein the mask is set so as to satisfy the above condition. The mask pattern includes a first exposure pattern region and a second exposure pattern region, and a part of an image of the first exposure pattern region formed by the first projection optical unit of the plurality of projection optical units. And a part of the image of the second projection optical unit formed by a second projection optical unit different from the first projection optical unit among the plurality of projection optical units is formed so as to overlap each other. The exposure method according to any one of claims 18 to 21, wherein: An exposure step of exposing the photosensitive substrate with a pattern of the mask by the exposure method according to any one of claims 18 to 22.
Developing the photosensitive substrate that has undergone the exposure step, and forming a mask layer having a shape corresponding to the pattern of the mask on the surface of the photosensitive substrate;
And a processing step of processing the surface of the photosensitive substrate through the mask layer.

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