JP2019028084A - Exposure device - Google Patents

Abstract

To enable reduction of exposure unevenness due to a joint of an exposure area when a plurality of projection optics system arranged in zigzag is used in an exposure device.SOLUTION: An exposure device 100 has an illumination light source 2, a visual field contraction 3 having a composite opening area and a single opening area formed alternately, in which a plurality of openings arranged in zigzag are formed around a first axial line as a center, a plurality of first projection optical systems for projecting optical images by first exposure light Land Lto a body to be exposed 6 respectively, and a light transmission amount reduction member arranged on a light path of the exposed light between the illumination light source 2 and the body to be exposed 6, for reducing light amount of exposed light for irradiation of a light amount correction zone on the body to be exposed 6 overlapping at least the single opening area in a plane view.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exposure apparatus.

For example, a scanning exposure apparatus is known as an apparatus for forming a pattern on a large substrate used in a liquid crystal device or the like.
As an example of such a scanning exposure apparatus, there is an exposure apparatus described in Patent Document 1.
In the exposure apparatus described in Patent Document 1, a mask is illuminated with illumination light, and a pattern image formed on the mask is exposed onto a plate, which is an object to be exposed, by a plurality of projection optical systems.
The mask and the plate can move in the X direction with respect to the projection optical system at the same speed synchronously. The projection optical systems are each composed of an erecting equal-magnification real imaging system, and are staggered along the Y direction orthogonal to the X direction.
The illumination light is irradiated to the mask through a parallelogram field stop having two sides facing each other in the X direction arranged on each optical axis of each projection optical system. Each field stop is arranged in such a positional relationship that opposite sides in the Y direction overlap each other when viewed from the X direction which is the scanning direction.
Each projection optical system projects the image of the pattern formed on the mask onto the plate as a plurality of parallelogram optical images arranged in a staggered manner in plan view. However, as the mask and the plate move in the X direction with respect to each projection optical system, each optical image scans the surface of the plate in the X direction. For this reason, when scanning in the X direction is completed, the plate is exposed with an image of the entire surface of the mask.
In such an exposure apparatus, in the scanning direction, a first region exposed by light passing through a single field stop, and a second region exposed by light passing through two field stops adjacent in the Y direction. Area and occur. The shape and arrangement of each field stop are set so that the scanning exposure amount in the first region is equal to the scanning exposure amount in the second region.
The exposure apparatus of Patent Document 1 controls the illumination intensity of illumination light so that the light intensity is uniform on each field stop by an illuminance sensor.
Such an exposure apparatus replicates the pattern of the mask on the plate by accurately transferring the pattern formed on the mask to the plate.

  In the projection exposure method described in Patent Document 2, in the scanning exposure apparatus, the drawing position of the reticle pattern and the substrate transport position are used in order to suppress “screen separation” caused by the overlay error of the projection area of the projection optical system. Is shifted by a predetermined amount in a direction perpendicular to the optical axis of the optical system and perpendicular to the scanning direction.

JP-A-11-160887 JP-A-10-62809

However, in the conventional scanning exposure apparatus as described above, a manufacturing error occurs between the pattern on the mask and the exposure pattern on the plate due to various factors.
For example, when the mask has a highly uniform grid pattern, the line width in a certain region changes as a whole even if the line widths of the individual patterns are compared and the fluctuation is difficult to see. Then, it may be easily visually recognized as shading unevenness. For example, such unevenness is particularly easily visible in a black matrix pattern of a color filter used in a liquid crystal device.
For this reason, it is necessary to suppress fluctuations in the line width of the pattern generated along the scanning direction of the exposure apparatus.
In the scanning exposure apparatus as described above, the present inventor has a phenomenon in which pattern density unevenness occurs at a pitch corresponding to the arrangement pitch of the field stops even when the exposure light amounts corresponding to the respective field stops are accurately matched. I found When the present inventor diligently studied this phenomenon, it was found that this density unevenness occurred because the line width of the pattern was slightly narrowed in a band-like region extending in the scanning direction. Furthermore, it has been found that the region where the density unevenness occurs is a seam region where the exposure regions by the adjacent field stops overlap.
This problem is specific to a scanning exposure apparatus that uses a plurality of projection optical systems. For example, as the demand for higher definition of liquid crystal devices increases, there is a strong demand for a technique for further reducing such line width unevenness.
Such density unevenness in the joint region is a phenomenon different from “screen separation” in Patent Document 2, for example, and cannot be solved by the method described in Patent Document 2.

  The present invention has been made in view of the above problems, and an exposure apparatus capable of reducing exposure unevenness caused by a joint of exposure areas when a plurality of staggered projection optical systems are used. An object is to provide an exposure method.

  In order to solve the above problems, an exposure apparatus according to an aspect of the present invention includes a light source that generates exposure light, and an opening amount in a first direction along the first axis in a plan view intersects the first axis. A plurality of openings arranged in a staggered manner around the first axis so as to be constant in a second direction along the second axis, and the plurality of openings in the first direction. Two of them are alternately formed in the second direction, with a composite opening region adjacent to each other, a single opening region in which one of the plurality of openings opens in the first direction, and the second direction. A diaphragm member disposed such that the plurality of openings are positioned between the light source and the photomask for exposure; and a plurality of the plurality of openings of the diaphragm member. The dew that has passed through each of the openings. A plurality of projection optical systems each projecting an optical image of light onto an exposure object, and disposed on the optical path of the exposure light between the light source and the exposure object, and at least the single aperture region in plan view And a light transmission amount reducing member that reduces the light amount of the exposure light applied to the light amount correction region on the exposure object that overlaps each other.

  In the exposure apparatus of the above aspect, the light transmission amount reducing member reduces the light amount of the exposure light applied to the first light amount correction region on the exposure object that overlaps at least the single opening region in plan view. And a first light transmission amount reducing unit that is provided adjacent to the first light transmission amount reduction unit in the second direction and overlaps the composite opening region in plan view. And a second light transmission amount reducing unit that reduces the amount of the exposure light irradiated to the second light amount correction region.

  In the exposure apparatus according to the above aspect, the first light transmission amount reduction unit includes a uniform density filter that uniformly reduces the transmittance of the exposure amount, and the second light transmission amount reduction unit includes the second direction. In the embodiment, the gradient density filter may be configured such that the transmittance of the exposure amount increases as the distance from the portion adjacent to the first light transmission amount reducing unit increases.

  In the exposure apparatus of the above aspect, the light transmission amount reducing member may be disposed between the projection optical system and the exposure object.

  According to the exposure apparatus of the present invention, when a plurality of projection optical systems arranged in a staggered manner are used, it is possible to reduce exposure unevenness caused by the joint of the exposure regions.

It is a typical front view which shows an example of the exposure apparatus of the 1st Embodiment of this invention. It is a top view of A view in FIG. It is a typical top view which shows an example of the photomask for exposure used for the exposure apparatus of the 1st Embodiment of this invention. It is a typical enlarged view which shows an example of the mask pattern of the photomask for exposure used for the exposure apparatus of the 1st Embodiment of this invention. It is a typical top view which shows an example of the field stop used for the exposure apparatus of the 1st Embodiment of this invention. It is a typical fragmentary sectional view which shows the structure of the principal part of the exposure apparatus of the 1st Embodiment of this invention. It is a typical top view which shows an example of the light transmission amount reducing member used for the exposure apparatus of the 1st Embodiment of this invention. It is a typical graph which shows the transmittance | permeability distribution along the BB line in FIG. It is a schematic diagram explaining the exposure of a comparative example. It is a schematic diagram explaining the effective exposure amount in exposure of a comparative example. It is a schematic diagram explaining the exposure in the exposure apparatus of the 1st Embodiment of this invention. It is a typical graph explaining the integrated light quantity in the exposure of the exposure apparatus of the 1st Embodiment of this invention. It is a typical top view which shows an example of the light transmission amount reducing member used for the exposure apparatus of the 2nd Embodiment of this invention. It is a typical graph which shows the transmittance | permeability distribution along the DD line in FIG. It is a typical graph explaining the integrated light quantity in the exposure of the exposure apparatus of the 2nd Embodiment of this invention. It is a typical top view which shows an example of the light transmission amount reducing member used for the exposure apparatus of the 3rd Embodiment of this invention. It is a typical graph which shows the transmittance | permeability distribution along the EE line | wire in FIG. It is a typical graph explaining the integrated light quantity in the exposure of the exposure apparatus of the 3rd Embodiment of this invention. It is a typical graph which shows the transmittance | permeability distribution of the light transmission amount reducing member of the exposure apparatus of the modification of the 3rd Embodiment of this invention. It is a typical graph explaining the integrated light quantity in exposure of the exposure apparatus of the modification of the 3rd Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. In all the drawings, even if the embodiments are different, the same or corresponding members are denoted by the same reference numerals, and common description is omitted.

[First Embodiment]
An exposure apparatus according to the first embodiment of the present invention will be described.
FIG. 1 is a schematic front view showing an example of an exposure apparatus according to the first embodiment of the present invention. FIG. 2 is a plan view as viewed from A in FIG. FIG. 3 is a schematic plan view showing an example of an exposure photomask used in the exposure apparatus of the first embodiment of the present invention. FIG. 4 is a schematic enlarged view showing an example of a mask pattern of an exposure photomask used in the exposure apparatus of the first embodiment of the present invention. FIGS. 5A and 5B are schematic plan views showing an example of a field stop used in the exposure apparatus according to the first embodiment of the present invention. FIG. 6 is a schematic partial sectional view showing the configuration of the main part of the exposure apparatus according to the first embodiment of the present invention. FIG. 7 is a schematic plan view showing an example of a light transmission amount reducing member used in the exposure apparatus of the first embodiment of the present invention. FIG. 8 is a schematic graph showing the transmittance distribution along the line BB in FIG. In the graph of FIG. 8, the horizontal axis represents the position in the X direction, and the vertical axis represents the transmittance.
In addition, since each drawing is a schematic diagram, the shape and dimension are exaggerated (the following drawings are also the same).

An exposure apparatus 100 shown in FIGS. 1 and 2 uses a plurality of projection optical systems to expose an exposure pattern of a photomask 1 (exposure photomask, see FIG. 1) to an object to be exposed 6 (exposure target) at the same magnification. Scanning exposure apparatus.
Before describing the detailed configuration of the exposure apparatus 100, an example of the photomask 1 will be described.

As shown in FIG. 3, the photomask 1 includes a light transmissive substrate 1A and a mask portion 1B.
As the light transmissive substrate 1A, it is possible to use an appropriate substrate having a light transmissive property capable of transmitting the illumination light of the exposure apparatus 100. For example, the light transmissive substrate 1A may be formed of a glass substrate. The outer shape of the light transmissive substrate 1A is not particularly limited. In the example shown in FIG. 3, the outer shape of the light transmissive substrate 1A is rectangular in plan view.

The mask unit 1 </ b> B includes a mask pattern P that is an exposure pattern projected onto the object 6 by the exposure apparatus 100. The mask pattern P is configured, for example, by patterning a light shielding layer made of metal or the like laminated on the light transmissive substrate 1A.
The mask pattern P used in the exposure apparatus 100 for the same magnification exposure may be the same shape as the exposure pattern formed on the object to be exposed 6.
The mask pattern P is two-dimensionally formed on the surface of the light transmissive substrate 1A in the y direction along the long side of the light transmissive substrate 1A and in the x direction along the short side of the light transmissive substrate 1A. Yes.
In order to describe the position of the mask pattern P on the light transmissive substrate 1A, an x coordinate axis is set in the x direction and a y coordinate axis is set in the y direction. In FIG. 3, as an example, an x coordinate axis and ay coordinate axis are set with the origin O as one vertex of the outer shape of the light transmissive substrate 1A. However, the origin O of the xy coordinate system may be set at an appropriate position in the light transmissive substrate 1A.

The specific shape of the mask pattern P is an appropriate shape necessary for the exposure pattern.
Hereinafter, as an example of the mask pattern P, an example in which the planar shape of the light transmission portion is a rectangular lattice will be described. Such a rectangular grid exposure pattern may be used, for example, to form a black matrix (BM) used for a color filter in a liquid crystal device.

FIG. 4 shows an enlarged view of the mask pattern P.
In the mask pattern P, light-shielding portions 1b having a rectangular shape in plan view are arranged in a rectangular lattice shape in the x direction and the y direction. For example, the arrangement pitch of the light shielding portions 1b is P _{x in} the x direction and P _y in the y direction. For example, when the photomask 1 is for BM formation, the pitch P _x (P _y ) matches the arrangement pitch of subpixels in the x direction (y direction).
Between each light shielding part 1b, the light transmissive part 1a in which the surface of the light transmissive substrate 1A (see FIG. 3) is exposed is formed. The light transmission part 1a is divided into a first linear part 1a _x extending in the x direction and a second linear part 1a _y extending in the y direction.
The first linear portion 1a _x, having a constant line width _{L 1y.} Similarly the second linear portion 1a _y has a constant line width _{L 1x.} For example, when the photomask 1 is for BM formation, the line widths L _1y and L _1x are equal to the line width of the BM in the y direction and the x direction, respectively.

Here, the description returns to the exposure apparatus 100.
As shown in FIGS. 1 and 2, the exposure apparatus 100 includes a base 7, a second drive unit 11, a first drive unit 10, an illumination light source 2 (light source), a field stop 3 (a stop member), and a projection optical unit 5. .

The base 7 has a flat upper surface 7a arranged in the horizontal direction in order to place the object 6 to be exposed. As shown in FIG. 1, the base 7 is supported by the second drive unit 11 so as to be movable in the Y direction (first direction, the direction from the left side to the right side in the drawing) in the horizontal direction. The configuration of the second drive unit 11 is not particularly limited. For example, the second drive unit 11 may be configured with a single-axis stage that can reciprocate in the Y direction. However, the 2nd drive part 11 may be comprised so that the base 7 can be moved to the X direction (2nd direction, the direction which goes to the near side from the paper surface in FIG. 1) orthogonal to a Y direction in a horizontal surface.
As shown in FIG. 2, in this embodiment, the moving direction of the base 7 is a direction along the axis O ₅ (first axis) extending in the Y direction (the direction from left to right in FIG. 2) in the horizontal direction. It is.
As shown by a two-dot chain line in the figure, the second driving unit 11 can move the base 7 to the movement limit in the Y direction and then move the base 7 in the direction opposite to the Y direction to return to the movement start position.

The exposure object 6 is exposed to an exposure pattern based on the optical image of the mask pattern P of the photomask 1 by the exposure apparatus 100. The object to be exposed 6 is formed in a rectangular plate shape that is smaller than the upper surface 7 a and is not larger than the photomask 1. The object to be exposed 6 is placed on the upper surface 7a so that the longitudinal direction thereof coincides with the Y direction.
The object to be exposed 6 is configured by applying a photosensitive resist for performing photolithography on an appropriate substrate.

As shown in FIG. 1, in the exposure apparatus 100, the photomask 1 is arranged at a position facing the object to be exposed 6 placed on the base 7. The photomask 1 is supported by a support unit (not shown) provided so as to be driven by the first drive unit 10. The first drive unit 10 is configured to be able to translate a support unit (not shown) in synchronization with the base 7 so as to maintain a certain distance from the upper surface 7 a of the base 7. As with the second drive unit 11, the first drive unit 10 may be a uniaxial stage movable in the Y direction, a biaxial stage movable in the XY direction, or the like.
The photomask 1 in the exposure apparatus 100 is arranged so that the positive direction of the y coordinate axis is opposite to the Y direction and the x coordinate axis is along the X direction.

  The illumination light source 2 generates illumination light (exposure light) having a wavelength for exposing the resist on the exposure object 6 in order to expose the exposure object 6. The illumination light source 2 is fixedly supported by a support member (not shown) above the moving area of the photomask 1. The illumination light source 2 irradiates illumination light vertically downward.

The field stop 3 is disposed between the illumination light source 2 and the moving area of the photomask 1. The field stop 3 is fixedly supported by a support member (not shown). The field stop 3 shapes the illumination light emitted by the illumination light source 2 and divides the illumination light into a plurality of illumination areas.
As shown in FIG. 5A, the field stop 3 includes a plurality of first openings 3A arranged at a pitch of w ₁ + w ₂ (where w ₁ <w ₂ ) in the X direction and Δ in the Y direction. And a plurality of second openings 3B arranged at a pitch of w ₁ + w ₂ in the X direction on an axis that is shifted in parallel by Δ (h> 2).

The plan view shape of the first opening 3A is an isosceles trapezoid whose apex angle is not a right angle. The first opening 3A includes a first side 3a, a second side 3b, a third side 3c, and a fourth side 3d. The first side 3a is the upper base of the isosceles trapezoid, and the second side 3b is the lower base of the isosceles trapezoid. The lengths of the first side 3a and the second side 3b are w ₁ and w ₂ , respectively. The first side 3a and the second side 3b are parallel lines separated by h in the Y direction. The third side 3c and the fourth side 3d are isosceles trapezoidal legs arranged in this order in the X direction.

The plan view shape of the second opening 3B is a shape obtained by rotating the first opening 3A by 180 ° in plan view. The position of the second opening 3B in the X direction is shifted by (w ₁ + w ₂ ) / 2 with respect to the first opening 3A. For this reason, the 2nd opening part 3B is arrange | positioned in the position facing the intermediate point between two 1st opening part 3A.
With such an arrangement, the first opening 3A and the second opening 3B are staggered along the axis O ₃ (second axis) extending in the X direction.
When viewed from the Y direction, the third sides 3c and the fourth sides 3d in the first opening 3A and the second opening 3B overlap each other. When viewed from the Y direction, the end portions of the first side 3a (second side 3b) of the first opening 3A and the second side 3b (first side 3a) of the second opening 3B are at the same position.

When the field stop 3 is viewed in the Y direction, the single opening region r _S where only one of the first opening 3A and the second opening 3B opens and both the first opening 3A and the second opening 3B open. Composite opening regions r _C appear alternately in the X direction.
In the field stop 3, the width in the X direction alone aperture region _{r S w 1,} the width in the X direction of the composite opening region _{r C} is _{(w 2 -w 1) / 2} .

The shape and arrangement of the first opening 3A and the second opening 3B in the field stop 3 may be set to an appropriate size according to the convenience of the arrangement of the projection optical units 5 described later. Below, the specific dimension example regarding 3 A of 1st opening parts and the 2nd opening part 3B is shown.
(W ₂ −w ₁ ) / 2 may be, for example, 14 mm or more and 18 mm. For example, h may be 25 mm or more and 45 mm. (W ₁ + w ₂ ) / 2 may be, for example, not less than 95 mm and not more than 100 mm. Δ may be, for example, 200 mm or more and 300 mm or less.

The field stop 3 in the exposure apparatus 100 may be replaced with, for example, a field stop 4 shown in FIG.
The field stop 4 includes a plurality of first openings 4A arranged at a pitch of 2w ₃ in the X direction, and a plurality of arrays arranged at a pitch of 2w ₂ in the X direction on an axis that is shifted in parallel by Δ in the Y direction. A second opening 4B.

The plan view shape of the first opening 4A is a parallelogram whose apex angle is not a right angle. The first opening 4A includes a first side 4a, a second side 4b, a third side 4c, and a fourth side 4d. The first side 4a and the third side 4c are opposite sides in the Y direction. The third side 4c and the fourth side 4d are opposite sides in the X direction. First side 3a, the length of the second side 3b are each _{w 3.} The lengths of the third side 3c and the fourth side 3d are w ₄ (where w ₄ <w ₃ ).

The plan view shape of the second opening 4B is the same as that of the first opening 4A. Position of the second opening 4B in the X direction, are offset by _{w 3} with respect to the first opening 4A. For this reason, the 2nd opening part 4B is arrange | positioned in the position facing the intermediate point between the two 1st opening parts 4A.
With such an arrangement, the first opening 4A and the second opening 4B are staggered along the axis O ₄ (second axis) extending in the X direction.
When viewed from the Y direction, the third sides 4c and the fourth sides 4d in the first opening 4A and the second opening 4B overlap each other. When viewed from the Y direction, the end portions of the first side 4a (second side 4b) of the first opening 4A and the second side 4b (first side 4a) of the second opening 4B are at the same position.

When the field stop 4 is viewed in the Y direction, the single opening region r _{S in} which only one of the first opening 4A and the second opening 4B opens, and both the first opening 4A and the second opening 4B open. Composite opening regions r _C appear alternately in the X direction.
In the field stop 4, the width in the X direction of the single opening region r _S is (w ₃ −w ₄ ), and the width in the X direction of the composite opening region r _C is w ₄ .
Hereinafter, an example in which the exposure apparatus 100 includes the field stop 3 will be described unless otherwise specified.

As shown in FIG. 1, the projection optical unit 5 is disposed above the object 6 on the base 7 and opposed to the field stop 3 with a moving region of the photomask 1 interposed therebetween. Has been. The projection optical unit 5 is fixedly supported by a support member (not shown).
As shown in FIG. 2, the projection optical unit 5 includes a plurality of first-row projection optical systems 5A (projection optical systems) and a plurality of second-row projection optical systems 5B (projections) arranged in a staggered manner along the axis O _3. Optical system). Each first-row projection optical system 5A and each second-row projection optical system 5B are provided with light attenuation filters 8 (see FIG. 6) described later.
Each second-row projection optical system 5B has the same configuration as the first-row projection optical system 5A except for the arrangement of the second-row projection optical system 5A.

As shown in FIG. 6, the first row projection optical system 5A (second row projection optical system 5B) includes a lens 5a and a lens barrel 5b.
The lens 5a is composed of an imaging optical system that forms an object image as an erecting equal-magnification image on the image plane.
The lens barrel 5b holds the lens 5a so that the optical axis of the lens 5a is parallel to the vertical axis.
The first row projection optical system 5A (second row projection optical system 5B) is disposed at a position where the mask pattern P of the photomask 1 and the upper surface of the exposure object 6 coated with a resist are conjugated with each other. The In the present embodiment, the outgoing light from the first row projection optical system 5A toward the exposure target 6 is a parallel light flux.

As shown by a two-dot chain line in FIG. 5A, the first row projection optical system 5A has a first opening portion so that an optical image of light transmitted through the first opening portion 3A can be projected onto the object to be exposed 6. It is arranged below 3A. The second row projection optical system 5B is disposed below the second opening 3B so that an optical image of light transmitted through the second opening 3B can be projected onto the object to be exposed 6.
The first row projection optical system 5A (second row projection optical system 5B) forms an optical image of light transmitted through the first opening 3A (second opening 3B) as an erecting equal-magnification image on the object 6 to be exposed. Project. For this reason, the optical images of the single opening region r _S and the composite opening region r _C in the first opening 3A (second opening 3B) are also projected onto the exposed object 6 facing each other in the vertical direction.

  Since the first row projection optical system 5A and the second row projection optical system 5B are arranged in the same staggered arrangement as the first opening 3A and the second opening 3B, the first opening 3A and the second The interval between the two openings 3B is set such that the first row projection optical system 5A and the second row projection optical system 5B do not interfere with each other. For this reason, the pitch Δ in the y direction between the first opening 3A and the second opening 3B may be a large value, for example, about 6 to 8 times the opening width h in the y direction.

  As shown in FIG. 5B, when the field stop 4 is used instead of the field stop 3, the first-row projection optical system 5A exposes an optical image of light that passes through the first opening 4A. It is arranged below the first opening 4A so that it can be projected onto the body 6. The second row projection optical system 5B is disposed below the second opening 4B so that an optical image of light transmitted through the second opening 4B can be projected onto the object 6 to be exposed.

As shown in FIG. 6, a light attenuation filter 8 (light transmission amount attenuation member) is disposed at the lower end of each lens barrel 5b in the projection optical unit 5. Each light attenuating filter 8 is fixed in position with respect to the lens 5a by a filter holder 9 fixed to the lower end of the lens barrel 5b.
The light attenuating filter 8 converts the exposure light L _2A (L _2B ) transmitted through the first row projection optical system 5A (second row projection optical system 5B) to exposure light L _5A (L _5B ).
The exposure light L _5A (L _5B ) is applied to a light amount correction region M ₁ (see FIGS. 7 and 11) described later on the object 6 to be exposed. Here, the light quantity correction area M ₁ on the object to be exposed 6, a region overlapping with at least a single aperture region r _S in a plan view. In the present embodiment, as an example, the light quantity correction area M ₁ is a single open region r _S only overlap region.

As shown in FIG. 7, the light attenuation filter 8 includes a light reduction unit 8a (uniform density filter) and a light transmission unit 8b.
The light reduction unit 8a is a part that attenuates the exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a with a constant transmittance T _L1 .
The dimming portion 8a is formed in a rectangular shape whose outer shape is along the X direction and the Y direction in plan view. Attenuating portion 8a is in plan view, is formed in a portion to cover the entire sole opening region r _S of the first opening 3A of the optical attenuation filter 8 faces (second opening 3B). Therefore, the width in the X direction of the attenuating portion 8a is equal to the width in the X direction alone opening region r _S of the first opening 3A of the optical attenuation filter 8 faces (second opening 3B). Width in Y direction of the light reduction unit 8a, the optical attenuation filter 8 is first opening 3A or the width in the Y direction alone opening region r _S (second opening 3B) opposed.

The light transmission part 8b is formed in the light attenuation filter 8 in a region excluding the light attenuation part 8a. The transmittance T _max of the light transmitting portion 8b is larger than the transmittance T _L1 of the light reducing portion 8a. The transmittance of the light transmitting portion 8b is more preferably 90% or more and 100% or less.

With such a configuration, the light attenuation filter 8 has a transmittance distribution as shown by a curve 201 in FIG. 8 in the X direction.
The code | symbol on the horizontal axis of FIG. 8 represents the position of the point of the same code | symbol on the BB line described in FIG. Point a is an end point on the negative side in the X direction of the light attenuation filter 8 along line BB. A section from the point b to the point d and a section from the point e to the point g are sections that overlap with the composite opening region r _C , respectively. Point c, f is the center point, respectively in the X direction and the composite opening region r _C. Section from the point d to the point e is a section overlapping the single open region r _S. A point h is an end point on the positive side in the X direction of the light attenuation filter 8 along the line BB.
The dimming part 8a is arranged between the point d and the point e. The light transmission part 8b is formed in each section from the point a to the point d and from the point e to the point h.
A curve 201 is a broken line that takes a constant value T _L1 between the point d and the point e and takes a constant value T _max (where T _max > T _L1 ) at other positions.

  The light attenuating filter 8 may be manufactured, for example, by depositing a metal thin film on a portion that becomes the light reducing portion 8a on the surface of the glass substrate.

The exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a by the light attenuation filter 8 having the above configuration is light-attenuated according to the transmittance of the light reducing unit 8a and the light transmitting unit 8b. Converted to L _5A (L _5B ). The transmittance T _L1 of the light reducing portion 8a is selected from a range of more than 0% and less than 100% so that unevenness of an effective exposure amount described later due to the exposure light L _5A (L _5B ) can be reduced. The method of determining the transmittance T _L1 of the attenuating portion 8a, will be described in the explanation of operation will be described later.

As shown in FIG. 6, the filter holder 9 holds the light attenuation filter 8 at a fixed position with respect to the first row projection optical system 5A (second row projection optical system 5B). A through hole 9 a that transmits at least the exposure light L _5A (L _5B ) that has passed through the light reducing portion 8 a is passed through the center of the filter holder 9.
The filter holder 9 is detachably attached to the lens barrel 5b from below. Detachment means of the filter holder 9, if placing attenuating portion 8a of the light attenuating filter 8 in plan view so as to overlap the range of light intensity correction region M ₁ described above is not particularly limited. For example, an appropriate mount that can be positioned in the circumferential direction with respect to the lens barrel 5b, screw fitting, or the like may be used. In the present embodiment, since the exposure light L _5A (L _5B ) emitted from the lens 5a is a parallel light flux along the optical axis, the alignment of the light attenuation filter 8 in the optical axis direction is not performed with high accuracy. May be.

When the light attenuating filter 8 is held in a state where the horizontal position is aligned by the filter holder 9, the light attenuating part 8a of the light attenuating part 8a is viewed in plan view in the light amount correction region M as described above. ₁ are arranged in a positional relationship overlapping with ₁ .

Next, the operation of the exposure apparatus 100 will be described.
FIG. 9 is a schematic diagram for explaining the exposure of the comparative example. FIGS. 10A and 10B are schematic views for explaining an effective exposure amount in the exposure of the comparative example. FIG. 11 is a schematic diagram for explaining exposure in the exposure apparatus of the first embodiment of the present invention. FIG. 12 is a schematic graph for explaining the integrated light quantity in exposure of the exposure apparatus according to the first embodiment of the present invention. In the graph of FIG. 12, the horizontal axis represents the position in the X direction, and the vertical axis represents the integrated light quantity.

Before describing the exposure operation of the exposure apparatus 100, first, the exposure operation and the exposure amount by the exposure apparatus 300 of the comparative example shown in FIG. 1 will be described. The exposure apparatus 300 includes a projection optical unit 305 instead of the projection optical unit 5 of the exposure apparatus 100 of the first embodiment. The projection optical unit 305 is configured by removing the light attenuation filter 8 from the projection optical unit 5.
FIG. 9 is an enlarged view of a part of the front end portion of the exposure target 6 disposed below the projection optical unit 305. Although not shown in FIG. 9, between the field stop 3 and the projection optical unit 305, the photomask 1 moves in the Y direction in synchronization with the object to be exposed 6 while facing the object to be exposed 6. (See FIG. 1).
As shown in FIG. 1, when the illumination light source 2 is turned on, exposure light L _2A and L _2B are irradiated to the field stop 3. The exposure lights L _2A and L _2B are transmitted through the first openings 3A and the second openings 3B (see FIG. 5) of the field stop 3 and are irradiated onto the photomask 1.
Of the light transmitted through the light transmitting portion 1a in the photomask 1, the light that has passed through the first opening 3A is transmitted by the first row projection optical system 5A, and the light that has passed through the second opening 3B is transmitted by the second row projection optical system. by 5B, respectively exposure light _{L 13A,} are equal magnification projected to the object to be exposed 6 as _{L 13B.}
As a result, as shown in FIG. 9, on the object 6 to be exposed, the first optical image I _13A that is the optical image of the first opening 3A and the second optical image that is the optical image of the second opening 3B. An optical image I _13B is formed. In the first light image I _13A and the second light image I _13B , a luminance distribution corresponding to an object image such as the mask pattern P is formed. However, in FIG. 9, the luminance distribution is not shown for simplicity.
Similar to the first opening 3A and the second opening 3B, the first optical image I _13A and the second optical image I _13B are staggered along the axis O ₁₃ parallel to the x-coordinate axis on the object 6 to be exposed. Arranged.

When the base 7 moves in the Y direction, each first optical image I _13A and each second optical image I _13B sweeps a band-like region having a width w ₂ as indicated by the oblique lines in the figure. For this reason, each 1st optical image _I13A and each 2nd optical image _I13B scan on the to-be-exposed body 6 to ay direction.
However, the first opening 3A and the second opening 3B are shifted by Δ in the Y direction. Therefore, the region where the first optical image I _13A and the second optical image I _13B are simultaneously swept is shifted by a distance (w ₁ + w ₂ ) / 2 in the x direction and shifted by a distance Δ in the y direction. .
Assuming that the moving speed of the base 7 is v (see FIG. 1), the second optical image I _13B is delayed by T = Δ / v, and the first optical image I _13A is scanned in advance in the y direction. Reach the area.
For example, when the time t ₀ when scanning is started is, the second optical image I _13B reaches the position in the y direction of the first optical image I _{13A at} the time t ₀ at the time t ₁ = t ₀ + T. . At this time, the second optical image I _13B just fits between the adjacent first optical images I _13A formed at time t ₀ .
That is, at the time t ₀ , the region in the x direction in which the first optical image I _13A is arranged is only exposed by the first optical image I _13A , but at the time t ₁ , The non-exposed portion is exposed with the second optical image I _13B . As a result, the region extending in the x direction is exposed in a strip shape with no time gap T and no gap. The leg of the isosceles trapezoid in the first optical image I _13A and the leg of the isosceles trapezoid in the second optical image I _13B constitute the boundary of the seam of the exposure area.

Mask portion 1B of the photomask 1 in plan view is located on the opposite direction side of the Y-direction than the second side 3b of the first opening 3A at time t _0. 9, as an example, at time t _0, when the tip in the y-direction of the mask portion 1B is in the second side 3b of the same position of the first opening 3A is shown. For this reason, at the time t ₀ , the lower base of the isosceles trapezoid in the first optical image I _13A is located at the end of the mask portion 1B.
In the region where the first light image I _13A swept by the scanning, the time t ₀ after the scan, the mask patterns P of the photomask 1 is gradually projected onto the object to be exposed 6. The exposure time of the mask pattern P is a time obtained by dividing the opening width h in the Y direction in the first opening 3A by the speed v. In the first side 3a and the rectangular region sandwiched between second side 3b of the first opening 3A, the exposure time t _f = h / v. In the following, that the exposure time t _f full exposure time.
However, in the triangular region sandwiched between the third side 3c and the fourth side 3d of the first opening 3A and the second side 3b, the exposure time in the x direction changes linearly from 0 to the full exposure time. .
Similarly, in a region where the second optical image I _13B is swept by scanning, exposure similar to that in the first optical image I _13A is performed with a delay of time T. Therefore, the region where the second light image I _13B swept is divided a region that is exposed in the full exposure time t _f, to the area to be exposed below the full exposure time t _f.
Area to be exposed below the full exposure time t _f is an exposure region related to the seam of the first optical image I _13A and the second light image I _13B.

In the comparative example, the areas exposed by the first light image I _13A and the second light image I _{13B with the} full exposure time t _f are separated from each other, and each is a band-like single exposure extending in the y direction with a width w _1. An area _AS is configured.
In contrast, the region of the width _{(w 1 + w 2) /} 2 between the independent exposure area _{A S} is the first optical image _{I 13A} and the second light image _{I 13B,} less than full exposure time _{t f} the composite exposure area a _C to be exposed.
Exposure time at each position in the x-direction in the composite exposure area A _C, simply exposure ratio of the first light image I _13A and the second light image I _13B are different, either the exposure time of the total is equal.
Therefore, an exposure amount in a single exposure area A _S, the exposure amount in the composite exposure area A _C, if the illumination light intensity in the first light image I _13A and the second light image I _13B are the same, each other Will be equal.

However, according to the present inventor's observation, when compared to the exposure pattern to be formed on a single exposure area A _S on the object to be exposed 6, the exposure pattern formed on the composite exposure area A _C, the light transmissive portion Line width tends to be slightly narrower.
Composite exposed region A _C extends in the y direction at a constant width, and because it is formed at a constant pitch in the x direction, the change in line width is likely to be recognized as a band-shaped density unevenness in the exposure pattern. For example, when a photomask for forming a BM is formed by the exposure apparatus 100, the size of the opening of the subpixel becomes uneven, so that a liquid crystal device in which regular color unevenness is easily visible may be formed.

The reason why the line widths are different even when the exposure time is the same is not necessarily clear, but the influence of the time difference represented by the time T can be considered.
The resist can be removed by the developer as a result of the progress of the photochemical reaction upon exposure. However, the photochemical reaction of the resist requires a certain amount of time for the reaction to start. On the other hand, when the exposure is interrupted, the reaction rapidly stops and the light reaction that has started is reset. As a result, since the effective exposure time is shorter in the intermittent exposure than in the continuous exposure, it is considered that the same effect as that in which the exposure amount is reduced occurs.
Therefore, effective exposure amount used in the photosensitive resist net in the composite exposure area A _C of the object to be exposed 6, if the same amount of light, the first light image I _13A and the second light image I _It is considered that it is determined by the ratio of the exposure time by _13B .

As shown schematically in FIG. 10 (a), and independent exposure area _{A S1} of the first optical image _{I 13A} is scanned, the independent exposure area _{A S2} where the first optical image _{I 13A} scans, sandwiched in composite exposed region a _C, and the exposure time of the first light image I _13A, the exposure time by the second optical image I _13B varies linearly along the x-direction.
For example, the position indicated by the point _{p 1} are the boundary position between the independent exposure area _{A S1,} 100% exposure time of the first light image _{I 13A,} the exposure time by the second optical image _{I 13B} 0% It is. When the ratio (%) of the exposure time at each point is expressed as _pn [t _A , t _B ], for example, p ₁ [100, 0], p ₂ [90, 10], p ₃ [80, 20], p ₄ [70, 30], p ₅ [60, 40], p ₆ [50, 50], p ₇ [40, 60], p ₈ [30, 70], p ₉ [20, 80]. , P ₁₀ [20, 80], p ₁₁ [0, 100]. In the following, the position coordinates of these points _{pn in} the x direction are represented by x _n (where n = 1,..., 11).
In this case, the effective exposure amount that affects the like to the line width (hereinafter, sometimes simply referred to as exposure), as shown in FIG. 10 (b), the composite exposure area A _C, substantially downward convex Shown in a V-shaped graph. Position _{x 1, x} exposure amount in _{11 q 1, q 11} is equal to the exposure amount _{q 0} in the respective independent exposure area _{A S.} For example, the exposure amount q ₆ at the position x _6, the exposure amount q lower than _0, the minimum value of the exposure amount in the composite exposure area A _C. The change rate of the exposure amount in the vicinity of the positions x ₁ and x _{11 and in} the vicinity of the position x ₆ changes smoothly. This graph is symmetrical with respect to the longitudinal axis passing through the position x _6.
Thus, the exposure amount in the composite exposure area A _C, which is represented by a continuous function as an independent variable the position coordinates in the x direction, the simple, may be approximated by the step change.
For example, as between the section _{A n} and the position _{x 2n-1} and the position _{x 2n + 1,} the average exposure of the interval _{A n,} each exposure amount in the interval _{A n} may be approximated.

As described above, in the exposure by the exposure apparatus 300 of the comparative example, also the opening amount viewed in the Y direction in the field stop 3 is constant in the X direction, the effective exposure amount in the composite exposure area A _C, alone reduced as compared with the exposure area a _S.
In the present embodiment, the projection optical unit 5 by providing the light attenuating filter 8, to reduce the exposure amount in a single exposure area A _S. Thus, the effective exposure unevenness due to decreased effective exposure amount in the composite exposed region A _C is reduced.
Hereinafter, the difference from the operation of the comparative example will be mainly described.

In the exposure operation of the exposure apparatus 100, the exposure lights L _5A and L _5B emitted from the projection optical unit 5 are transmitted through the light attenuation filter 8. For this reason, the light amount distribution of the light image projected onto the exposure object 6 by the exposure light L _5A and L _5B is different from the light amount distribution of the first light image I _13A and the second light image I _13B. This is different from the operation of the exposure apparatus 300. The reduction in the amount of light of the optical image projected on the object to be exposed 6 is based on the transmittance of the light reducing portion 8a and the transmittance of the light transmitting portion 8b of the light attenuation filter 8.
As shown in FIG. 11, the exposure light _L 5A _{(L 5B),} the first optical image _{I 5A} projected on the object to be exposed 6 (second optical image _{I 5B),} the first light attenuation image _{I 8a} And the second light attenuation image _I8b .
The first light attenuation image _I8a is formed in a region overlapping the light reduction portion 8a in the range of the first opening 3A (second opening 3B). In the case of this embodiment, the first light attenuation image I _8a is an optical image in the range of the single opening region r _S. The light amount of the first light attenuation image I _8a is lower than the light amount of the first light image I _13A (second light image I _13B ) in accordance with the transmittance T _L1 of the light reduction unit 8a.
The second light attenuation image I _8b is formed in a region overlapping the light transmission portion 8b in the range of the first opening 3A (second opening 3B). In the case of the present embodiment, the second light attenuation image I _8b is an optical image in the range of the composite opening region r _C. The amount of light of the second light attenuation image I _8b decreases from the amount of light of the first light image I _13A (second light image I _13B ) in accordance with the transmittance T _max of the light transmission portion 8b. However, since T _max > T _L1 , the light amount of the second light attenuation image I _8b is larger than the light amount of the first light attenuation image I _8a .

For this reason, the integrated light amount when the first optical image I _5A and the second optical image I _5B are scanned on the object to be exposed 6 does not decrease so much in the composite aperture region r _C , whereas the single aperture region In r _S decreases greater.
For easy comparison with the comparative example, FIG. 12 shows the integrated light quantity during scanning exposure when the transmittance T _max is 100%.
The code | symbol on the horizontal axis of FIG. 12 represents the position of the point of the same code | symbol on CC line described in FIG. Points i, j, k, m, n, p, q, r on the CC line are points a, b, c, d, e, f, g, h on the BB line of the optical attenuation filter 8, respectively. It corresponds to. Therefore, the section from the section and the point n from the point j to the point m to the point q is a composite exposed region A _C overlapping the composite opening region r _C at each plan view. Section from the point m to a point n is an independent exposure area A _S overlapping the single open region r _S in plan view. In the present embodiment, independent exposure area A _S is in the light quantity correction area M _1.
A curve 202 (see the solid line) in FIG. 12 indicates the integrated light amount in the present embodiment, and a curve 203 (see the alternate long and short dash line) indicates the integrated light amount in the comparative example. However, in the composite exposed region _{A C,} curve 203 overlaps the curve 202.

As shown in curve 202 and 203, the integrated light quantity in this embodiment, the composite exposure area A _C, becomes similar to the integrated light quantity of the comparative example. For this reason, in the composite exposure area _AC , for example, the integrated light amount decreases by ΔQ (= q ₀ −q ₆ ) between the point j and the point k.
In contrast, the integrated light quantity of a single exposure area _{A S} overlapping the light quantity correction area _{M 1} is a constant value Q (provided _{that, q 6 <Q <q 0} ).
Thus, in this embodiment, the total fluctuation range ΔQ of the integrated light quantity is the same as that in the comparative example. However, since the integrated light quantity of a single exposure area A _S is reduced from q ₀ in Q, the variation amount of the exposure of the composite exposed region A _C relative to the exposure amount of independent exposure area A _S is smaller than Delta] Q.
In particular, by setting the transmittance _{T L1} of the light reducing portion 8a as appropriate, _{Q =} if _{(q 0 + q 6) /} 2, independent exposure area _A of the exposure of the composite exposed region _{A C} relative to the exposure amount of _S Since the fluctuation amount is ΔQ / 2, the exposure unevenness is minimized. For this reason, it is more preferable that the transmittance T _L1 of the dimming portion 8a is set to be Q = (q ₀ + q ₆ ) / 2.
In this way, the unevenness of the exposure of the composite exposed region A _C relative to the exposure amount of independent exposure area A _S is reduced, exposure unevenness resulting from the seam of the exposure area is reduced. Thereby, for example, fluctuations in the line width corresponding to the mask pattern P are reduced, and a more accurate exposure pattern can be obtained.

  As described above, according to the exposure apparatus 100 of the present embodiment, when using a plurality of projection optical systems arranged in a staggered manner, it is possible to reduce exposure unevenness caused by the joint of the exposure regions.

[Second Embodiment]
An exposure apparatus according to the second embodiment of the present invention will be described.
FIG. 13 is a schematic plan view showing an example of a light transmission amount reducing member used in the exposure apparatus of the second embodiment of the present invention. FIG. 14 is a schematic graph showing the transmittance distribution along the line DD in FIG. The horizontal axis of the graph of FIG. 14 represents the position in the X direction, and the vertical axis represents the transmittance. FIG. 15 is a schematic graph for explaining the integrated light quantity in exposure of the exposure apparatus according to the second embodiment of the present invention. In the graph of FIG. 15, the horizontal axis represents the position in the X direction, and the vertical axis represents the integrated light quantity.

As shown in FIGS. 1 and 2, the exposure apparatus 110 of this embodiment includes a projection optical unit 15 instead of the projection optical unit 5 of the exposure apparatus 100 of the first embodiment.
As shown in FIG. 6, the projection optical unit 15 includes a light attenuation filter 18 (light transmission amount attenuation member) instead of the light attenuation filter 8 of the projection optical unit 5 in the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIG. 6, the light attenuating filter 18 is similar to the light attenuating filter 8 in the first embodiment. Each lens of the first row projection optical system 5A and the second row projection optical system 5B in the projection optical unit 15 is used. It is arranged at the lower end of the lens barrel 5b. Each light attenuating filter 18 is fixed in position relative to the lens 5a by a filter holder 9 fixed to the lower end of the lens barrel 5b.
The light attenuating filter 18 converts the exposure light L _2A (L _2B ) transmitted through the first row projection optical system 5A (second row projection optical system 5B) to exposure light L _15A (L _15B ).
The exposure light L _15A (L _15B ) is applied to a light amount correction region M ₂ (see FIG. 13) described later on the object 6 to be exposed. Here, the light quantity correction area M ₂ on the object to be exposed 6, a region overlapping with at least a single aperture region r _S in a plan view. In the present embodiment, as an example, there is a light quantity correction area M ₂ alone opening region r _S and solely opening region r _S region overlapping with part of each composite opening region r _C adjacent to the opposite ends of.

  As shown in FIG. 13, the light attenuation filter 18 includes a light reduction unit 18a (uniform density filter) instead of the light reduction unit 8a of the first embodiment.

Attenuating portion 18a is the less than 50% of the first X-direction width of each composite opening region r _C X direction both end portions of the dimming portion 8a of the embodiments only, and is extended outwardly. In the example illustrated in FIG. 13, as an example, the dimming portion 18 a is widened on both sides in the X direction by 25% of the width in the X direction of the composite opening region r _C than the dimming portion 8 a.
Attenuating portion 18a is in a plan view, the whole and sole opening region r _S of the first opening 3A (second opening 3B), a portion of the composite opening region r _C in the X direction on both sides adjacent thereto (In FIG. 13, a quarter of the composite opening region r _C ) are arranged so as to overlap each other.
The transmittance of the dimming unit 18a is the same as that of the dimming unit 8a in the first embodiment.

  In the present embodiment, the light transmission part 8b is formed in a region of the light attenuation filter 18 excluding the light reduction part 18a.

With such a configuration, the light attenuation filter 18 has a transmittance distribution as indicated by a curve 204 in FIG. 14 in the X direction.
14 represents the position of the point of the same sign on the DD line described in FIG. The meanings of points a to h are the same as in the description of the first embodiment. However, the point c ′ (f ′) is the midpoint of the line segment cd (ef).
The curve 204 takes the minimum value T _L1 between the point c ′ and the point f ′, similarly to the dimming unit 8a in the first embodiment, and takes a constant value T _max at other positions.
The light attenuation filter 18 is manufactured in the same manner as the light attenuation filter 8.

The exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a by the light attenuating filter 18 having such a configuration is light-attenuated according to the transmittance of the light reducing unit 18a and the light transmitting unit 8b. Converted to L _15A (L _15B ).

According to the exposure apparatus 110, exposure is performed in the same manner as the exposure apparatus 100 of the first embodiment.
In the exposure operation of the exposure apparatus 110, the exposure lights L _15A and L _15B emitted from the projection optical unit 15 are transmitted through the light attenuation filter 18. For this reason, the light quantity distribution of the first optical image (second optical image) projected onto the object to be exposed 6 by the exposure light L _15A and L _15B is the first optical image I _8A and second optical image. The difference from the light amount distribution of the optical image I _8B is different from the operation of the exposure apparatus 100.

FIG. 15 shows a graph of the integrated light quantity when the exposure light L _15A and L _15B are scanned on the object 6 to be exposed. However, FIG. 15 shows the integrated light quantity at the time of scanning exposure in the case where the transmittance T _max is 100% so that it can be easily compared with the above-described comparative example, as in FIG.
Reference signs i to r on the horizontal axis in FIG. 15 represent corresponding points of points a to h in FIG. However, the positions corresponding to the points c ′ and f ′ are indicated by symbols m ′ and n ′, respectively. The points j ′ and q ′ represent positions corresponding to the points f ′ and c ′ of the dimming unit 8a disposed in the second column projection optical system 5B adjacent to the first column projection optical system 5A.
Therefore, the section from the section and the point n from the point j to the point m to the point q is a composite exposed region A _C overlapping the composite opening region r _C at each plan view. Section from the point m to a point n is an independent exposure area A _S overlapping the single open region r _S in plan view.
In the present embodiment, the light amount correction region M ₂ irradiated with the light transmitted through the light reducing portion 18 a of the light attenuation filter 18 is a region that overlaps the entire single opening region r _S and the composite opening region r _{C on} both sides in the X direction. And an area overlapping with a quarter of
A curve 205 (see the solid line) in FIG. 15 shows the integrated light quantity in the present embodiment, and a curve 203 (see the alternate long and short dash line) shows the integrated light quantity in the comparative example. A curve 206 (see a broken line) indicates the amount of light attenuation due to the action of each light attenuation filter 18.

As shown in curve 206, cumulative quantity of light in the present embodiment, the range of light intensity correction region M _2, since the transmission amount is reduced at a constant rate, the accumulated light quantity of the comparative example represented by the curve 203, the entire Decline. On the graph, the integrated light amount of the comparative example translates downward. For example, the integrated light quantity from the point m to a point n decreases from q ₀ in Q. Similarly, the amount of light in each region from point j to point j ′, point m ′ to point m, point n to point n ′, and point q to point q ′ falls below the amount of light Q from point m to point n. .
Therefore, as shown in curve 205, cumulative quantity of light in the present embodiment, Q (provided _{that, q 6 <Q <q 0} ) The independent exposure area _{A S,} the composite exposure area _{A C,} from _{q 6} of Q The light quantity distribution which vibrates between is shown.
According to the optical attenuation filter 18 in this embodiment, and the transmittance T _L2, by setting the transmittance of the rate of change of the first light attenuating portion 18a and the second light attenuating section 18b, the appropriate, the integrated light quantity The total variation width Q-q ₆ can be made smaller than the total variation width ΔQ of the integrated light quantity of the comparative example.
Thus, in this embodiment, the total fluctuation range Q-q ₆ itself of the integrated light quantity can be reduced as compared with the comparative example. Further, since also reduced the size of the exposure amount irregularity in the composite exposure area A _C, exposure unevenness resulting from the seam of the exposure area is reduced. Thereby, for example, fluctuations in the line width corresponding to the mask pattern P are reduced, and a more accurate exposure pattern can be obtained.

  As described above, according to the exposure apparatus 110 of this embodiment, when using a plurality of projection optical systems arranged in a staggered manner, it is possible to reduce exposure unevenness caused by the joint of the exposure areas.

[Third Embodiment]
An exposure apparatus according to the third embodiment of the present invention will be described.
FIG. 16 is a schematic plan view showing an example of a light transmission amount reducing member used in the exposure apparatus of the third embodiment of the present invention. FIG. 17 is a schematic graph showing a transmittance distribution along the line EE in FIG. The horizontal axis of the graph in FIG. 17 represents the position in the X direction, and the vertical axis represents the transmittance. FIG. 18 is a schematic graph for explaining the integrated light quantity in the exposure of the exposure apparatus according to the third embodiment of the present invention. In the graph of FIG. 18, the horizontal axis represents the position in the X direction, and the vertical axis represents the integrated light quantity.

As shown in FIGS. 1 and 2, the exposure apparatus 120 of this embodiment includes a projection optical unit 25 in place of the projection optical unit 5 of the exposure apparatus 100 of the first embodiment.
As shown in FIG. 6, the projection optical unit 25 includes a light attenuation filter 28 (light transmission amount attenuation member) instead of the light attenuation filter 8 of the projection optical unit 5 in the first embodiment.
Hereinafter, a description will be given centering on differences from the first embodiment.

As shown in FIG. 6, the light attenuating filter 28 is similar to the light attenuating filter 8 in the first embodiment, and each lens of the first row projection optical system 5A and the second row projection optical system 5B in the projection optical unit 25. It is arranged at the lower end of the lens barrel 5b. The position of each light attenuating filter 28 relative to the lens 5a is fixed by the filter holder 9 fixed to the lower end of the lens barrel 5b.
The light attenuating filter 28 converts the exposure light L _2A (L _2B ) transmitted through the first row projection optical system 5A (second row projection optical system 5B) to exposure light L _25A (L _25B ).
The exposure light L _25A (L _25B ) is irradiated on the light amount correction region M ₂ (see FIG. 16) similar to that in the second embodiment on the object to be exposed 6.

  As shown in FIG. 16, the light attenuation filter 28 includes a first dimming unit 28a (uniform density filter), a second dimming unit 28b (gradient density filter), and a third dimming unit 28c (gradient density filter). And a light transmission part 18c similar to that of the second embodiment.

The first dimming unit 18a is a part that attenuates the exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a with a constant transmittance T _L3 . The first dimming portion 18a is formed in the same manner as the dimming portion 8a in the first embodiment except that the transmittance is different.

The second dimming unit 28b transmits the exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a in the first light amount correction region m ₁ in the first opening 3A (second opening 3B). This is a portion that gradually attenuates in the positive direction of the X direction in the range of the rate T _max to T _L3 .
The third light reduction unit 28c transmits the exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a in the second light amount correction region m ₁ in the first opening 3A (second opening 3B). This is a portion that gradually attenuates in the negative direction of the X direction in the range of the rate T _max to T _L3 .

Rate of change of the transmittance in the second light attenuating section 28b and the third light reducing portion 28c is as required for the light intensity correction in the light amount correction area M _2, for example, experiments, are set on the basis of such simulation. The rate of change of transmittance in the second dimming unit 28b and the third dimming unit 28c may be constant (linear change) or may be changed based on an appropriate function. The change rate of the transmittance may be monotonous or non-monotonic. Furthermore, the change in transmittance is not limited to a smooth change. For example, the transmittance may change stepwise.

With such a configuration, the light attenuation filter 28 has a transmittance distribution as shown by a curve 207 in FIG. 17 in the X direction.
The code | symbol on the horizontal axis of FIG. 17 represents the position of the point of the same code | symbol on the EE line described in FIG. The meanings of points a to h are the same as in the description of the first embodiment.
The curve 207 takes T _max at the point c, the transmittance gradually decreases from the point c to the point d, and takes a constant value T _L3 from the point d to the point e. In the curve 207, the transmittance gradually increases from the point e toward the point f, and takes T _max at the point f. The curve 207 takes a constant value T _max at other positions.

  The light attenuating filter 28 may be manufactured, for example, by depositing a metal thin film on a portion of the surface of the glass substrate that becomes the first dimming portion 28a, the second dimming portion 28b, and the third dimming portion 28c. Good.

The exposure light L _2A (L _2B ) transmitted through the field stop 3 and the lens 5a by the light attenuating filter 28 having such a configuration causes the first dimming unit 28a, the second dimming unit 28b, and the third dimming unit 28c. , And exposure light L _25A (L _25B ) that is light-attenuated according to the transmittance of the light transmitting portion 18c. The transmittance T _L3 is selected from the range of more than 0% and less than 100% so that the unevenness of the effective exposure amount described later by the exposure light L _25A (L _25B ) can be reduced.

According to the exposure apparatus 120, exposure is performed in the same manner as the exposure apparatus 100 of the first embodiment.
In the exposure operation of the exposure apparatus 120, the exposure lights L _25A and L _25B emitted from the projection optical unit 25 are transmitted through the light attenuation filter 28. For this reason, the light quantity distribution of the first optical image (second optical image) projected onto the object to be exposed 6 by the exposure lights L _25A and L _25B is the first optical image I _8A and the second optical image. The difference from the light amount distribution of the optical image I _8B is different from the operation of the exposure apparatus 100.

FIG. 18 shows a graph of the integrated light quantity when the exposure light L _25A and L _25B are scanned on the object 6 to be exposed. However, FIG. 18 shows the integrated light quantity at the time of scanning exposure in the case where the transmittance T _max is 100% so that it can be easily compared with the above-described comparative example, as in FIG.
Reference signs i to r on the horizontal axis in FIG. 18 represent corresponding points of points a to h in FIG.
Therefore, the section from the section and the point n from the point j to the point m to the point q is a composite exposed region A _C overlapping the composite opening region r _C at each plan view. Section from the point m to a point n is an independent exposure area A _S overlapping the single open region r _S in plan view.
A curve 208 (see the solid line) in FIG. 18 indicates the integrated light amount in the present embodiment, and a curve 203 (see the alternate long and short dash line) indicates the integrated light amount in the comparative example. A curve 209 (see the broken line) indicates the amount of light attenuation due to the action of each light attenuation filter 28.

As shown in curve 208, cumulative quantity of light in the present embodiment, both independent exposure area A _S and the composite exposed region A _C because that is a light quantity correction area M _2, the comparative example represented by the curve 203 The integrated light quantity decreases as a whole.
In the present embodiment, the transmittance T _L3 is set by the first dimming unit 28a so that the integrated light amount of the first light amount correction region m ₁ is Q ₄ (where q ₆ <Q ₄ <q ₀ ). The
Therefore, the second light attenuating section 28b accumulated light quantity maximum value _{Q 3} in (third light attenuating portion 28c) by the second light quantity correction area _{m 2 satisfies} the _{Q 4 <Q 3 <q 0} . The minimum value of the second integrated quantity of light of the light quantity correction region m ₂ becomes q _6.
As a result, since the total fluctuation range of the integrated light quantity shown by the curve 209 is Q ₃ −q ₆ <ΔQ, the fluctuation range of the integrated light quantity itself is reduced as compared with the comparative example.
Further, by setting the transmittance T _L3 may be appropriately set the value of Q ₄ which is a cumulative amount of light in most independent exposure area A _C to an intermediate value between Q ₃ and q _6. In this case, since it is possible to non-uniform exposure for the accumulated amount of light Q ₄ below _{(Q 3 + q 6) /} 2 (<ΔQ / 2), as compared with the first embodiment, the exposure unevenness caused by the seam of the exposure area Further reduced. Thereby, for example, fluctuations in the line width corresponding to the mask pattern P are reduced, and a more accurate exposure pattern can be obtained.
In particular, in the second embodiment, there is a portion where the light amount is lower than the lowest integrated light amount of the comparative example in order to reduce the total fluctuation range of the integrated light amount, whereas the light attenuation filter of the present embodiment 28, the minimum value of the integrated light quantity is the same as in the comparative example. For this reason, according to the present embodiment, the relative reduction amount of the integrated light amount is smaller than that in the second embodiment.

  As described above, according to the exposure apparatus 120 of this embodiment, when using a plurality of projection optical systems arranged in a staggered manner, it is possible to reduce exposure unevenness caused by the joint of the exposure areas.

[Modification]
Next, a specific modified example that can further reduce the exposure unevenness in the present embodiment will be described.
FIG. 19 is a schematic graph showing the transmittance distribution of the light transmission amount reducing member of the exposure apparatus according to the modification of the third embodiment of the present invention. In the graph of FIG. 19, the horizontal axis represents the position in the X direction, and the vertical axis represents the transmittance. FIG. 20 is a schematic graph for explaining the integrated light quantity in the exposure of the exposure apparatus according to the modification of the third embodiment of the present invention. In the graph of FIG. 20, the horizontal axis represents the position in the X direction, and the vertical axis represents the integrated light quantity.

This modification differs from the third embodiment only in the transmittance setting by the light attenuation filter 28.
As shown in FIG. 19, in this modification, the transmittance T _L3 of the first light reducing portion 28a is sized to be set a cumulative amount of light at a single exposure area A _S to q _6.
In this modification, the transmittance of the second light attenuating section 28b (third light attenuating portion 28c) so as to offset the decrease in the effective cumulative amount of the comparative example in the composite exposure area A _C, from point d It is set so as to gradually increase from the transmission point T _L3 to T _max from the point c (from the point e to the point f).
The correction effect of the integrated light amount in the light attenuation filter 28 of the present modification is inverted in the up and down direction of the curve 203 (see the alternate long and short dash line) indicating the integrated light amount of the comparative example as shown by the curve 209 (see the broken line) in FIG. It is represented by a curved line.
As a result, the effective accumulated light quantity of the exposure light transmitted through the optical attenuation filter 28 of this modification, a constant value q ₆ as shown by curve 208 (see solid line) in FIG. 20.
Thus, according to this modification, it is possible to eliminate uneven exposure by optimizing the transmittance distribution of the light attenuation filter 28 with respect to the effective integrated light amount of the comparative example. .

  In the description of each of the above embodiments, in the exposure apparatus, the light source, the diaphragm member, and the projection optical system (hereinafter referred to as the exposure unit) are fixed, and the exposure photomask and the exposure object (hereinafter referred to as the exposure object). In the example, the scanning exposure is performed by the movement of the above. However, in the scanning exposure, it is only necessary that the exposure unit and the object to be exposed move relative to each other in the scanning direction (Y direction, first direction) and the relative scanning is performed. Therefore, in the exposure apparatus, the exposure unit may move in the scanning direction and the object to be exposed may be fixed. Furthermore, in the exposure apparatus, the exposure unit and the object to be exposed may move.

  In the description of each of the above embodiments, an example in which the first direction and the second direction are orthogonal to each other has been described. However, the first direction and the second direction only need to intersect with each other on a plane, and the intersection angle is not limited to a right angle.

  In the description of each of the above embodiments, the example in which the photomask 1 is moved by the first driving unit 10 and the object to be exposed 6 is moved by the second driving unit 11 that moves the base 7 has been described. However, the photomask 1 and the base 7 may be moved in the scanning direction by one driving unit.

  In the description of each of the embodiments described above, the field diaphragms 3 and 4 have been described as examples in the case of one aperture that overlaps the entire projection optical system. However, the field stops 3 and 4 are configured by a combination of two or more apertures as long as the aperture is formed in the NA range of the projection optical system and light other than the light transmitted through the aperture is not incident on the projection optical system. May be.

  In the description of each of the above embodiments, the light transmission amount reducing member has been described as an example in the case where the light transmission amount reducing member is disposed between the projection optical system and the exposure target. However, the light transmission amount reducing member may be disposed at any position between the light source and the exposure target.

  In the description of the first embodiment, the example in which the projection optical unit 5 exposes the entire width of the exposure target 6 in the X direction has been described. However, as long as the exposure pattern of the object to be exposed 6 can be exposed by the single photomask 1, the projection optical unit 5 may be large enough to cover a part in the X direction. In this case, the entire exposure object 6 is exposed by performing scanning exposure in the Y direction in the exposure apparatus 100 a plurality of times while shifting in the X direction.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, and is limited only by the appended claims.

1 Photomask (Photomask for exposure)
2 Illumination light source (light source)
3, 4 Field stop (aperture member)
3A, 4A First opening (opening)
3B, 4B Second opening (opening)
5, 15, 25 Projection optical unit 5A First row projection optical system (projection optical system)
5B Second-row projection optical system (projection optical system)
6 Object to be exposed (object to be exposed)
8, 18, 28 Light attenuation filter (light transmission attenuation member)
8a, 18a Light reduction part (uniform density filter)
28a 1st light reduction part (1st light transmission amount reduction part, uniform density filter)
28b Second dimming unit (second light transmission amount reducing unit, gradient density filter)
28c 3rd light reduction part (2nd light transmission amount reduction part, gradient density filter)
100, 110, 120, the exposure device _{A C} composite exposure area _{A S, A S1, A S2} independent exposure region _{I 5A, I 8A} first light image _{I 5B, I 8B} second optical image _{L 2A, L 2B, L 5A} , L _5B , L _15A , L _15B , L _25A , L _25B , exposure light M ₁ , M ₂ light quantity correction area m ₁ first light quantity correction area m ₂ second light quantity correction area O ₃ , O ₄ axis ( Second axis)
O ₅ axis (first axis)
P mask pattern r _C compound opening region r _S single opening region

Claims (4)

A light source that generates exposure light;
Centered on the first axis so that the opening amount in the first direction along the first axis in plan view is constant in the second direction along the second axis intersecting the first axis. A plurality of openings arranged in a staggered manner, and a composite opening region in which two of the plurality of openings are adjacent to each other in the first direction, and the plurality of openings in the first direction. A single aperture region in which one of the apertures and an aperture formed alternately in the second direction and arranged such that the plurality of apertures are located between the light source and the exposure photomask Members,
A plurality of projection optical systems that are arranged to face each of the plurality of openings of the diaphragm member and project the optical images of the exposure light that have passed through the plurality of openings, respectively, onto an exposure object;
The exposure light that is disposed on the optical path of the exposure light between the light source and the exposure object, and is applied to the light amount correction area on the exposure object that overlaps at least the single opening area in plan view. A light transmission amount reducing member for reducing the amount of light;
An exposure apparatus comprising: The light transmission amount reducing member is:
A first light transmission amount reducing unit that reduces the light amount of the exposure light irradiated to the first light amount correction region on the exposure object that overlaps at least the single opening region in plan view;
The exposure that is provided adjacent to the first light transmission amount reduction unit in the second direction and is irradiated to a second light amount correction region on the exposure object that overlaps the composite opening region in a plan view. A second light transmission amount reducing unit for reducing the amount of light;
The exposure apparatus according to claim 1, comprising: The first light transmission amount reducing unit is:
It consists of a uniform density filter that uniformly reduces the transmittance of the exposure amount,
The second light transmission amount reducing unit is:
A gradient density filter in which the transmittance of the exposure amount increases as the distance from the portion adjacent to the first light transmission amount reduction unit in the second direction increases.
The exposure apparatus according to claim 2. The light transmission amount reducing member is:
Arranged between the projection optical system and the exposure object,
The exposure apparatus according to claim 1.

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