JP7052242B2 - Exposure device - Google Patents

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 for a liquid crystal apparatus or the like.
An example of such a scanning exposure apparatus is the exposure apparatus described in Patent Document 1.
In the exposure apparatus described in Patent Document 1, a mask is illuminated with illumination light, and an image of a pattern formed on the mask is exposed to a plate 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 in synchronization. Each of the projection optical systems is composed of an upright equal-magnification real imaging system, and is arranged in a staggered manner along the Y direction orthogonal to the X direction.
Illumination light is applied to the mask through a parallelogram field diaphragm having two sides facing each other in the X direction arranged on each optical axis of each projection optical system. Each field diaphragm is arranged so that the 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 an image of a pattern formed on a mask onto a plate as a plurality of parallel quadrilateral light images arranged in a staggered manner in a plan view. However, as the mask and plate move in the X direction for each projection optical system, each light image scans the surface of the plate in the X direction. Therefore, when the scan in the X direction is completed, the plate is exposed by the 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 diaphragm and a second region exposed by light passing through two adjacent field diaphragms in the Y direction. Areas occur. The shape and arrangement of each field diaphragm are set so that the scanning exposure amount in the first region and the scanning exposure amount in the second region are equal to each other.
In the exposure apparatus of Patent Document 1, the illumination intensity of the illumination light is also controlled by the illuminance sensor so that the light intensity becomes uniform on each field diaphragm.
Such an exposure apparatus replicates the mask pattern 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, in order to suppress "screen division" caused by the superposition error of the projection area of the projection optical system, the drawing position of the rectil pattern and the transport position of the substrate are suppressed. It is described that and is shifted by a predetermined amount in a direction perpendicular to the optical axis of the optical system and perpendicular to the scanning direction.

Japanese Unexamined Patent Publication No. 11-1608887 Japanese Unexamined Patent Publication No. 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 grid pattern with high uniformity, the line width in a certain region changes as a whole even if the line widths of the individual patterns are difficult to see even when compared. In some cases, it can be easily visually recognized as uneven shading. For example, in a black matrix pattern of a color filter used in a liquid crystal display, such unevenness is particularly easy to be visually recognized.
Therefore, it is necessary to suppress fluctuations such as the line width of the pattern generated along the scanning direction of the exposure apparatus.
In the above-mentioned scanning exposure apparatus, the present inventor has a phenomenon in which pattern density unevenness occurs at a pitch corresponding to the arrangement pitch of the field diaphragm even if the exposure light amounts corresponding to each field diaphragm are accurately matched. I found. When the present inventor diligently studied this phenomenon, it was found that this density unevenness was caused by the line width of the pattern being slightly narrowed in the band-shaped region extending in the scanning direction. Furthermore, it was also found that the region where the density unevenness occurs is a seam region where the exposed regions due to the adjacent field diaphragms overlap.
This problem is peculiar to a scanning exposure apparatus using 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 seam region is a phenomenon different from, for example, "screen division" in Patent Document 2, 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 when a plurality of staggered projection optical systems are used, an exposure apparatus capable of reducing exposure unevenness caused by a seam in an exposure region and an exposure apparatus. It is an object of the present invention to provide an exposure method.

In order to solve the above problems, in the exposure apparatus of the first aspect of the present invention, the light source that generates the exposure light and the opening amount in the first direction along the first axis in the plan view are the first. A plurality of staggered openings along the second axis are formed so as to be constant in the second direction along the second axis intersecting the axis, and the plurality of openings are formed in the first direction. A composite opening region in which two of the openings are adjacent to each other with a gap between them and a single opening region in which one of the plurality of openings opens in the first direction alternate in the second direction. The aperture member is formed so that the plurality of openings are located between the light source and the photomask for exposure, and the aperture members are arranged to face each of the plurality of openings of the aperture member. On the optical path of the exposed light between the light source and the exposed object, a plurality of projection optical systems each projecting an optical image of the exposed light transmitted through each of the plurality of openings onto the exposed object. A light transmission amount reducing member for reducing the amount of light of the exposure light applied to the light amount correction region on the exposure object, which is arranged in the above and overlaps with at least the single opening region in a plan view. The amount reducing member comprises a uniform density filter that uniformly reduces the transmission rate of the exposure amount, and is irradiated to a first light amount correction region on the exposure object that overlaps at least the single opening region in a plan view. Inclined density in which the transmission rate of the exposure amount increases as the distance from the first light transmission amount reducing portion that reduces the amount of exposure light and the portion adjacent to the first light transmission amount reduction portion in the second direction increases. The second light amount correction region on the exposed object, which is composed of a filter and is provided adjacent to the first light transmission amount reducing portion in the second direction and overlaps the front composite opening region in a plan view, is irradiated. A second light transmission amount reducing unit for reducing the amount of the exposed light is provided.

In the exposure apparatus of the first aspect, the light transmittance reducing member may be arranged 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 pattern are used, it is possible to reduce the exposure unevenness caused by the seam of the exposure region.

It is a schematic front view which shows an example of the exposure apparatus of 1st Embodiment of this invention. It is a top view of A view in FIG. It is a schematic plan view which shows an example of the exposure photomask used in the exposure apparatus of 1st Embodiment of this invention. It is a schematic enlarged view which shows an example of the mask pattern of the exposure photomask used in the exposure apparatus of 1st Embodiment of this invention. It is a schematic plan view which shows an example of the field diaphragm used in the exposure apparatus of 1st Embodiment of this invention. It is a schematic partial sectional view which shows the structure of the main part of the exposure apparatus of 1st Embodiment of this invention. It is a schematic plan view which shows an example of the light transmittance reducing member used in the exposure apparatus of 1st Embodiment of this invention. It is a schematic graph which shows the transmittance distribution along the line BB in FIG. 7. It is a schematic diagram explaining the exposure of a comparative example. It is a schematic diagram explaining the effective exposure amount in the exposure of the comparative example. It is a schematic diagram explaining the exposure in the exposure apparatus of 1st Embodiment of this invention. It is a schematic graph explaining the integrated light amount in the exposure of the exposure apparatus of 1st Embodiment of this invention. It is a schematic plan view which shows an example of the light transmittance reducing member used in the exposure apparatus of 2nd Embodiment of this invention. It is a schematic graph which shows the transmittance distribution along the DD line in FIG. It is a schematic graph explaining the integrated light amount in the exposure of the exposure apparatus of the 2nd Embodiment of this invention. It is a schematic plan view which shows an example of the light transmittance reducing member used in the exposure apparatus of 3rd Embodiment of this invention. It is a schematic graph which shows the transmittance distribution along the EE line in FIG. It is a schematic graph explaining the integrated light amount in the exposure of the exposure apparatus of the 3rd Embodiment of this invention. It is a schematic graph which shows the transmittance distribution of the light transmittance reducing member of the exposure apparatus of the modification of the 3rd Embodiment of this invention. It is a schematic graph explaining the integrated light amount in the exposure of the exposure apparatus of the modification of the 3rd Embodiment of this invention.

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

[First Embodiment]
The 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 of the view A in FIG. FIG. 3 is a schematic plan view showing an example of an exposure photomask used in the exposure apparatus according to 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 according to the first embodiment of the present invention. 5 (a) and 5 (b) are schematic plan views showing an example of a field diaphragm used in the exposure apparatus according to the first embodiment of the present invention. FIG. 6 is a schematic partial cross-sectional view showing the configuration of a 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 transmittance reducing member used in the exposure apparatus according to the first embodiment of the present invention. FIG. 8 is a schematic graph showing the transmittance distribution along the line BB in FIG. 7. In the graph of FIG. 8, the horizontal axis represents the position in the X direction, and the vertical axis represents the transmittance.
Since each drawing is a schematic view, the shape and dimensions are exaggerated (the same applies to the following drawings).

The exposure apparatus 100 shown in FIGS. 1 and 2 uses a plurality of projection optical systems to scan and expose the exposure pattern of the photomask 1 (exposure photomask, see FIG. 1) to the exposed object 6 (exposure object) at the same magnification. It is a scanning type exposure apparatus.
Before explaining 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-transmitting substrate 1A, it is possible to use an appropriate substrate having a light-transmitting property capable of transmitting the illumination light of the exposure apparatus 100. For example, the light transmissive substrate 1A may be composed 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 a plan view.

The mask unit 1B includes a mask pattern P that is an exposure pattern projected onto the exposed body 6 by the exposure apparatus 100. The mask pattern P is configured by, for example, patterning a light-shielding layer such as metal laminated on the light-transmitting substrate 1A.
The mask pattern P used in the exposure apparatus 100 for equal-magnification exposure may have the same shape as the exposure pattern formed on the exposed body 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 the x direction along the short side of the light transmissive substrate 1A. There is.
In order to describe the position of the mask pattern P on the light transmissive substrate 1A, an x-axis is set in the x-direction and a y-axis is set in the y-direction. In FIG. 3, as an example, an x-axis axis and a y-axis axis with one vertex of the outer shape of the light transmissive substrate 1A as the origin O are set. However, the origin O of the xy coordinate system may be set at an appropriate position on the light transmissive substrate 1A.

The specific shape of the mask pattern P is an appropriate shape required for the exposure pattern.
Hereinafter, as an example of the mask pattern P, an example will be described in which the shape of the light transmitting portion in a plan view is a rectangular grid. Such a rectangular grid-shaped exposure pattern may be used, for example, to form a black matrix (BM) used for a color filter in a liquid crystal display.

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 a plan view are arranged in a rectangular grid pattern in the x-direction and the y-direction. For example, the arrangement pitch of the light-shielding portion 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 ) corresponds to the arrangement pitch of the sub-pixels in the x direction (y direction).
A light transmitting portion 1a with an exposed surface of the light transmitting substrate 1A (see FIG. 3) is formed between the light shielding portions 1b. The light transmitting portion 1a is divided into a first linear portion 1ax extending in the _x direction and a second linear portion 1ay extending in the _y direction.
The first linear portion _1ax has a constant line width _L1y . Similarly, the second linear portion _1ay 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 of the exposure apparatus 100 is returned to.
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 diaphragm 3 (aperture member), and a projection optical unit 5. , Equipped with.

The base 7 has a flat upper surface 7a arranged in the horizontal direction for mounting the exposed body 6. As shown in FIG. 1, the base 7 is movably supported by the second drive unit 11 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 by a uniaxial stage capable of reciprocating in the Y direction. However, the second drive unit 11 may be configured to be able to move the base 7 in the X direction (second direction, the direction from the back of the paper to the front in FIG. 1) orthogonal to the Y direction in the horizontal plane.
As shown in FIG. 2, in the present embodiment, the moving direction of the base 7 is a direction along the axis O5 ₍ first axis) extending in the Y direction (direction from left to right in FIG. 2) in the horizontal direction. Is.
As shown by the two-dot chain line in the figure, the second drive 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 exposed body 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 exposed body 6 is formed in the shape of a rectangular plate smaller than the upper surface 7a and having a size equal to or smaller than the photomask 1. The exposed body 6 is placed on the upper surface 7a so that its longitudinal direction coincides with the Y direction.
The exposed body 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 exposed body 6 placed on the base 7. The photomask 1 is supported by a support portion (not shown) provided so as to be driveable by the first drive unit 10. The first drive unit 10 can move the support portion (not shown) in parallel with the base 7 so as to maintain a constant distance from the upper surface 7a of the base 7. As the first drive unit 10, like the second drive unit 11, a uniaxial stage movable in the Y direction, a biaxial stage movable in the XY direction, or the like may be used.
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.

Since the illumination light source 2 exposes the exposed body 6, the illumination light source 2 generates illumination light (exposure light) having a wavelength that exposes the resist on the exposed body 6. The illumination light source 2 is fixedly supported by a support member (not shown) above the moving region of the photomask 1. The illumination light source 2 irradiates the illumination light vertically downward.

The field diaphragm 3 is arranged between the illumination light source 2 and the moving area of the photomask 1. The field diaphragm 3 is fixedly supported by a support member (not shown). The field diaphragm 3 shapes the illumination light emitted by the illumination light source 2 and divides the illumination light into a plurality of illumination regions.
As shown in FIG. 5A, the field diaphragm 3 has 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. It has a plurality of second openings 3B arranged at a pitch of w ₁ + w ₂ in the X direction on an axis shifted in parallel by (where 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 is composed of 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 a 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. Therefore, the second opening 3B is arranged at a position facing the intermediate point between the two first openings 3A.
With such an arrangement, the first opening 3A and the second opening _3B are staggered along the axis O3 (second axis) extending in the X direction.
When viewed from the Y direction, the third sides 3c of the first opening 3A and the second opening 3B and the fourth sides 3d overlap each other. When viewed from the Y direction, the ends 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 diaphragm 3 is viewed in the Y direction, both the single opening region _rS in which 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. The compound opening region r _C and the compound opening region r C appear alternately in the X direction.
In the field diaphragm 3, the width of the single aperture region r _S in the X direction is w ₁ , and the width of the composite aperture region r _C in the X direction is (w ₂ -w ₁ ) / 2.

The shape and arrangement of the first opening 3A and the second opening 3B in the field diaphragm 3 may be set to an appropriate size depending on the convenience of the arrangement of the projection optical units 5 described later. Specific dimensional examples of the first opening 3A and the second opening 3B are shown below.
(W2 _- w1) / ₂ may be, for example, 14 mm or more and 18 mm. h may be, for example, 25 mm or more and 45 mm. (W ₁ + w ₂ ) / 2 may be, for example, 95 mm or more and 100 mm or less. Δ may be, for example, 200 mm or more and 300 mm or less.

The field diaphragm 3 in the exposure apparatus 100 may be replaced with, for example, the field diaphragm 4 shown in FIG. 5 (b).
The field diaphragm 4 has a plurality of first openings 4A arranged at a pitch of 2w ₃ in the X direction, and a plurality of first openings 4A arranged at a pitch of 2w ₂ in the X direction on an axis deviated in parallel by Δ in the Y direction. It has 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 is composed of 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. The lengths of the first side 3a and the second side 3b are w3 _, respectively. The lengths of the third side 3c and the fourth side 3d are w ₄ (where w ₄ <w ₃ ), respectively.

The plan view shape of the second opening 4B is the same as that of the first opening 4A. The position of the second opening 4B in the X direction is deviated by _w3 with respect to the first opening 4A. Therefore, the second opening 4B is arranged at a position facing the intermediate point between the two first openings 4A.
With such an arrangement, the first opening 4A and the second opening 4B are staggered along the axis _O4 (second axis) extending in the X direction.
When viewed from the Y direction, the third sides 4c of the first opening 4A and the second opening 4B and the fourth sides 4d overlap each other. When viewed from the Y direction, the ends 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 diaphragm 4 is viewed in the Y direction, both the single opening region _rS 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. The compound opening region r _C and the compound opening region r C appear alternately in the X direction.
In the field diaphragm 4, the width of the single aperture region r _S in the X direction is (w ₃ -w ₄ ), and the width of the composite aperture region r _C in the X direction is w ₄ .
Hereinafter, unless otherwise specified, an example of the case where the exposure apparatus 100 includes the field diaphragm 3 will be described.

As shown in FIG. 1, the projection optical unit 5 is arranged above the exposed body 6 on the base 7 and so as to face each other with the moving region of the photomask 1 sandwiched between the projection optical unit 5 and the field diaphragm 3. Has been done. 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 O3. It is equipped with an optical system). Each of the first-row projection optical system 5A and each second-row projection optical system 5B is provided with a light attenuation filter 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 that the arrangement is different from that of the first-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 image of an object as an upright equal-magnification image on the image plane.
The lens barrel 5b holds the lens 5a in a posture in which 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 arranged at a position in which the mask pattern P of the photomask 1 and the upper surface of the exposed body 6 coated with the resist are in a positional relationship conjugate with each other. Ru. In the present embodiment, the emitted light from the first-row projection optical system 5A toward the exposed body 6 is a parallel light flux.

As shown by the alternate long and short dash line in FIG. 5A, the first row projection optical system 5A has a first opening so that an optical image of light transmitted through the first opening 3A can be projected onto the exposed body 6. It is located below 3A. The second-row projection optical system 5B is arranged below the second opening 3B so that an optical image of light transmitted through the second opening 3B can be projected onto the exposed body 6.
The first-row projection optical system 5A (second-row projection optical system 5B) forms an upright equal-magnification image of light transmitted through the first opening 3A (second opening 3B) on the exposed body 6. Project. Therefore, 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 body 6 facing each other in the vertical direction.

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, so that the first opening 3A and the second opening 3A and the second opening 3B are arranged in the same staggered arrangement. The distance between the two openings 3B is sized so that the first-row projection optical system 5A and the second-row projection optical system 5B do not interfere with each other. Therefore, the pitch Δ between the first opening 3A and the second opening 3B in the y direction 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 diaphragm 4 is used instead of the field diaphragm 3, the first-row projection optical system 5A exposes an optical image of light transmitted 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 arranged below the second opening 4B so that an optical image of light transmitted through the second opening 4B can be projected onto the exposed body 6.

As shown in FIG. 6, a light attenuation filter 8 (light transmittance attenuation member) is arranged at the lower end of each lens barrel 5b in the projection optical unit 5. The position of each light attenuation filter 8 with respect to the lens 5a is fixed by a filter holder 9 fixed to the lower end of the lens barrel 5b.
The light attenuation filter 8 is an exposure light L _2A (L _2B ) transmitted through the first-row projection optical system 5A (second-row projection optical system 5B), and the exposure light L _5A (L) in which at least a part of the light amount is reduced. Convert to _5B ).
The exposure light L _5A (L _5B ) irradiates the light amount correction region M ₁ (see FIGS. 7 and 11) described later on the exposed body 6. Here, the light amount correction region M1 on the exposed body 6 is a region that overlaps with at _least the single aperture region _rS in a plan view. In the present embodiment, as an example, the light amount correction region M ₁ is a region that overlaps only the single aperture region r _S.

As shown in FIG. 7, the light attenuation filter 8 includes a dimming unit 8a (uniform density filter) and a light transmitting unit 8b.
The dimming unit 8a is a portion that attenuates the exposure light L _2A (L _2B ) transmitted through the field diaphragm 3 and the lens 5a at a constant transmittance TL ₁ .
The dimming portion 8a is formed in a rectangular shape whose outer shape is along the X direction and the Y direction in a plan view. The dimming portion 8a is formed in a portion that covers the entire single opening region _rS of the first opening 3A (second opening 3B) with which the light attenuation filter 8 faces in a plan view. Therefore, the width of the dimming portion 8a in the _X direction is equal to the width of the single opening region rS of the first opening 3A (second opening 3B) facing the light attenuation filter 8 in the X direction. The width of the dimming portion 8a in the Y direction is equal to or greater than the width of the single opening region _rS of the first opening 3A (second opening 3B) facing the light attenuation filter 8 in the Y direction.

The light transmitting portion 8b is formed in a region of the light attenuation filter 8 excluding the dimming portion 8a. The transmittance T _max of the light transmitting portion 8b is larger than the transmittance _TL1 of the dimming 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 the curve 201 in FIG. 8 in the X direction.
The reference numerals on the horizontal axis of FIG. 8 represent the positions of the points of the same reference numerals on the BB line shown in FIG. 7. The point a is an end point on the negative direction side in the X direction of the light attenuation filter 8 on the BB line. The section from the point b to the point d and the section from the point e to the point g are sections that overlap with the composite opening region _rC , respectively. The points c and f are the midpoints in the X direction with the composite opening region _rC , respectively. The section from the point d to the point e is a section overlapping the single opening region _rS . The point h is an end point on the positive direction side in the X direction of the light attenuation filter 8 on the BB line.
The dimming unit 8a is arranged between the point d and the point e. The light transmitting portion 8b is formed in each section from the point a to the point d and from the point e to the point h.
The curve 201 is a polygonal line having a constant value _TL1 between the points d and e and a constant value _Tmax (where _Tmax > _TL1 ) at other positions.

The light attenuation filter 8 may be manufactured, for example, by depositing a metal thin film on a portion of the surface of the glass substrate to be the dimming portion 8a.

The exposure light L _2A (L _2B ) transmitted through the field aperture 3 and the lens 5a by the light attenuation filter 8 having such a configuration is the exposure light light-attenuated according to the transmittance of the dimming portion 8a and the light transmission portion 8b. It is converted to L _5A (L _5B ). The transmittance TL1 of the dimming unit 8a is selected from a 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 5A} (L _5B ) can be reduced. The method of determining the transmittance _TL1 of the dimming unit 8a will be described in the operation description 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 9a that allows at least the exposure light L _5A (L _5B ) that has passed through the dimming portion 8a is passed through the central portion of the filter holder 9.
The filter holder 9 is detachably attached to the lens barrel 5b from below. The means for attaching and detaching the filter holder 9 is not particularly limited as long as the dimming portion 8a of the light attenuation filter 8 can be arranged so as to overlap the range of the above _- mentioned light amount correction region M1 in a plan view. For example, an appropriate mount, screw fitting, or the like that can be positioned in the circumferential direction with respect to the lens barrel 5b 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 cannot be performed with high accuracy. You may.

When the light attenuation filter 8 is held in a state where the position in the horizontal direction is aligned by the filter holder 9, in the light attenuation filter 8, as described above, the dimming portion 8a has the light amount correction region M in a plan view. It is arranged in a positional relationship that overlaps with ₁ .

Next, the operation of the exposure apparatus 100 will be described.
FIG. 9 is a schematic diagram illustrating the exposure of the comparative example. 10 (a) and 10 (b) are schematic views illustrating an effective exposure amount in the exposure of the comparative example. FIG. 11 is a schematic diagram illustrating exposure in the exposure apparatus according to the first embodiment of the present invention. FIG. 12 is a schematic graph illustrating the integrated light amount in the 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 intensity.

Before explaining 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 shows a part of the tip portion of the exposed body 6 arranged below the projection optical unit 305 in an enlarged manner. Although not shown in FIG. 9, the photomask 1 moves in the Y direction in synchronization with the exposed body 6 in a state of facing the exposed body 6 between the field diaphragm 3 and the projection optical unit 305. (See Fig. 1).
As shown in FIG. 1, when the illumination light source 2 is turned on, the exposure light L _2A and L _2B are applied to the field diaphragm 3. The exposure light L _2A and L _2B pass through each of the first opening 3A and each second opening 3B (see FIG. 5) of the field diaphragm 3 and irradiate the photomask 1.
Of the light transmitted through the light transmitting portion 1a in the photo mask 1, the light passing through the first opening 3A is the first-row projection optical system 5A, and the light passing through the second opening 3B is the second-row projection optical system. By 5B, the exposure light L _13A and L _13B are projected onto the exposed object 6 at the same magnification, respectively.
As a result, as shown in FIG. 9, on the exposed body 6, the first light image I _13A , which is an optical image of the first opening 3A, and the second light image, which is the light image of the second opening 3B, are on the exposed body 6. 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 a mask pattern P is formed. However, in FIG. 9, the illustration of the luminance distribution is omitted for the sake of simplicity.
The first optical image I _13A and the second optical image I _13B , like the first opening 3A and the second opening 3B, are staggered along the axis O ₁₃ parallel to the x-axis axis on the exposed body 6. Be arranged.

As the base 7 moves in the Y direction, each first light image I _13A and each second light image I _13B sweeps a strip _- shaped region of width w2, as shown by the diagonal lines in the figure. Therefore, each of the first light image I _13A and each second light image I _13B scans on the exposed body 6 in the y direction.
However, the first opening 3A and the second opening 3B are displaced by Δ in the Y direction. Therefore, the region swept by the first light image I _13A and the second light image I _13B at the same time is shifted by the distance (w ₁ + w ₂ ) / 2 in the x direction and is shifted by the 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 scanning in the y direction in advance. Reach the area of.
For example, assuming that the scanning is started at time t ₀ , the second light image I _13B arrives at the position in the y direction of the first light image I _13A at time t ₀ at time t ₁ = t ₀ + T. .. At this time, the second light image I _13B is just fitted between the first light images I _13A that are adjacent to each other and are formed at time _t0 .
That is, at time t ₀ , the region in the x direction in which the first light image I _13A is lined up is only exposed by the first light image I _13A in a discrete manner, but at time t ₁ , the region of the same region is exposed. The unexposed portion is exposed by the second light image I _13B . As a result, the region extending in the x direction is exposed in a band shape without a gap with a time difference T. The isosceles trapezoidal leg in the first light image I _13A and the isosceles trapezoidal leg in the second light image I _13B form the boundary of the seam of the exposed area.

In a plan view, the mask portion 1B of the photomask 1 is located on the side opposite to the second side 3b of the first opening 3A at time _t0 in the Y direction. In FIG. 9, as an example, a case where the tip of the mask portion 1B in the y direction is at the same position as the second side 3b of the first opening 3A is shown at time _t0 . Therefore, at 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 swept by the first optical image I _13A by scanning, the mask pattern P of the photomask 1 is projected onto the exposed body 6 by scanning after time _t0 . The exposure time of the mask pattern P is the time obtained by dividing the opening width h in the Y direction in the first opening 3A by the speed v. In the rectangular region sandwiched between the first side 3a and the second side 3b of the first opening 3A, the exposure time t _f is h / v. Hereinafter, the exposure time t _f is referred to as a 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 the region swept by the second light image I _13B by scanning, the same exposure as by the first light image I _13A is performed with a delay of time T. Therefore, the region swept by the second light image I _13B is divided into a region exposed at the full exposure time t _f and a region exposed at the full exposure time t _f or less.
The region exposed in less than the full exposure time t _f is an exposure region related to the seam of the first light image I _13A and the second light image I _13B .

In the comparative example, the regions exposed by the first light image I _13A and the second light image I _13B at the full exposure time t _f are separated from each other, and the strip-shaped single exposure extending in the y direction with the width w ₁ respectively. It constitutes the area _AS .
On the other hand, the region of width (w ₁ + w ₂ ) / 2 between the single exposure regions _AS is less than the full exposure time t _f by the first optical image I _13A and the second optical image I _13B . It constitutes the composite exposure area _AC to be exposed.
The exposure time at each position in the x direction in the composite exposure region _AC is the same except that the exposure ratios of the first light image I _13A and the second light image I _13B are different.
Therefore, if the exposure amount in the single exposure area _AS and the exposure amount in the composite exposure area _AC are the same in the first light image I _13A and the second light image I _13B , they are mutually. Will be equal.

However, according to the observation of the present inventor, the exposure pattern formed in the composite exposure region _AC is the light transmission portion as compared with the exposure pattern formed in the single exposure region _AS on the exposed body 6. The line width tends to be slightly narrower.
Since the composite exposure region _AC extends in the y direction with a constant width and is formed at equal pitches in the x direction, the change in the line width is easily 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 openings of the sub-pixels becomes uneven, so that there is a possibility that a liquid crystal device in which regular color unevenness is easily visible may be formed.

The reason why the line width is different even if the exposure time is the same is not always 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 photochemical reaction proceeding when exposed. However, in the photochemical reaction of resist, it takes some time to start the reaction. On the other hand, when the exposure is interrupted, the reaction stops rapidly and the started photoreaction is reset. As a result, it is considered that the effective exposure time is shorter in the intermittent exposure than in the continuous exposure, so that the same effect as the decrease in the exposure amount is produced.
Therefore, if the effective exposure amount used for the net exposure of the resist in the composite exposure region _AC on the exposed body 6 is the same amount of light, the first light image I _13A and the second light image I It is considered to be determined by the ratio of the exposure time to _13B .

As schematically shown in FIG. 10A, it is sandwiched between the single exposure region _AS1 scanned by the first optical image I _13A and the single exposure region _AS2 scanned by the first optical image I _13A . In the combined exposure region _AC , the exposure time by the first light image I _13A and the exposure time by the second light image I _13B change linearly along the x direction.
For example, since the position indicated by the point p1 is the boundary position with the _single exposure region _AS1 , the exposure time by the first optical image I _13A is 100%, and the exposure time by the second optical image I _13B is 0%. 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], p4 [70,30], p5 [ _60,40 ], p6 [ _50,50 ], p7 [ _40,60 ], p8 [ _30,70 ], _p9 [ _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).
At this time, the effective exposure amount that affects the line width and the like (hereinafter, may be simply referred to as an exposure amount) is abbreviated as downwardly convex in the composite exposure area _AC , as shown in FIG. 10 (b). It is shown by a V-shaped graph. The exposure amounts q ₁ and q ₁₁ at the positions x ₁ and x ₁₁ are equal to the exposure amount q ₀ in the single exposure region _AS , respectively. For example, the exposure amount q ₆ at the position x ₆ is lower than the exposure amount q ₀ , and is the minimum value of the exposure amount in the composite exposure region _AC . The rate of change of the exposure amount in the vicinity of the positions x ₁ and x ₁₁ and the vicinity of the position x ₆ changes smoothly. This graph is symmetrical with respect to the vertical axis passing through position _x6 .
As described above, the exposure amount in the composite exposure region _AC is represented by a continuous function having the position coordinates in the x direction as an independent variable, but may be simply approximated by a stepwise change.
For example, with the section An between the position x _{2n -1} and the position x _{2n + 1} , each exposure amount in the section _An may be approximated by the average exposure amount of the section An.

As described above, in the exposure by the exposure device 300 of the comparative example, even if the aperture amount seen in the Y direction in the field diaphragm 3 is constant in the X direction, the effective exposure amount in the composite exposure region _AC is independent. It is lower than the exposure area _AS .
In the present embodiment, the projection optical unit 5 includes the light attenuation filter 8 to reduce the exposure amount in the single exposure region _AS . As a result, effective exposure unevenness due to a decrease in the effective exposure amount in the composite exposure region _AC is reduced.
Hereinafter, the points different from the operation of the above 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 pass through the light attenuation filter 8. Therefore, the light amount distribution of the light image projected on the exposed body 6 by the exposed 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 . It is different from the operation of the exposure device 300. The decrease in the amount of light of the light image projected on the exposed body 6 is based on the transmittance of the dimming portion 8a of the light attenuation filter 8 and the transmittance of the light transmitting portion 8b.
As shown in FIG. 11, the first light image I _5A (second light image I _5B ) projected onto the exposed body 6 by the exposure light L _5A (L _5B ) is the first light attenuation image I _8a . And the second light attenuation image I _8b .
The first light attenuation image I _8a is formed in a region overlapping the dimming portion 8a in the range of the first opening 3A (second opening 3B). In the case of the present embodiment, the first light attenuation image I _8a is an optical image in the range of the single aperture region _rS . The amount of light of the first light attenuation image I _8a is reduced from the amount of light of the first light image I _13A (second light image I _13B ) according to the transmittance _{TL 1} of the dimming unit 8a.
The second light attenuation image I _8b is formed in a region overlapping the light transmitting 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 aperture region _rC . The amount of light in the second light attenuation image I _8b is reduced from the amount of light in the first light image I _13A (second light image I _13B ) according to the transmittance T _max of the light transmitting portion 8b. However, since T _max > TL ₁ , the amount of light in the second light attenuation image I _8b is larger than the amount of light in the first light attenuation image I _8a .

Therefore, when the first light image I _5A and the second light image I _5B scan on the exposed body 6, the integrated light amount does not decrease so much in the composite aperture region r _C , whereas it is a single aperture region. In r _S , it decreases more.
To make it easier to compare with the comparative example, FIG. 12 shows the integrated light amount at the time of scanning exposure when the transmittance T _max is 100%.
The reference numeral on the horizontal axis of FIG. 12 represents the position of the point of the same reference numeral on the CC line shown in FIG. The points i, j, k, m, n, p, q, and r on the CC line are the points a, b, c, d, e, f, g, h on the BB line of the light attenuation filter 8, respectively. It corresponds to. Therefore, the section from the point j to the point m and the section from the point n to the point q are each a composite exposure region _AC that overlaps with the composite aperture region r _C in a plan view. The section from the point m to the point n is a single exposure region _AS that overlaps with the single aperture region r _S in a plan view. In the present embodiment, the _single exposure region _AS is the light amount correction region M1.
Curve 202 (see solid line) in FIG. 12 shows the integrated light amount in this embodiment, and curve 203 (see one-dot chain line) shows the integrated light amount in the comparative example. However, in the composite exposure region _AC , the curve 203 overlaps with the curve 202.

As shown in the curves 202 and 203, the integrated light amount in the present embodiment is the same as the integrated light amount in the comparative example in the composite exposure region _AC . Therefore, in the composite exposure region _AC , for example, the integrated light amount is reduced by ΔQ (= q ₀ − q ₆ ) between the points j and k.
On the other hand, the integrated light amount of the _single exposure area _AS overlapping the light amount correction area M1 is a constant value Q (however, q ₆ <Q <q ₀ ).
As described above, in the present embodiment, the total variation width ΔQ of the integrated light amount is the same as that of the comparative example. However, since the integrated light amount of the single exposure area _AS is reduced from q ₀ to Q, the fluctuation amount of the exposure amount of the composite exposure area _AC with respect to the exposure amount of the single exposure area _AS becomes smaller than ΔQ.
In particular, if Q = (q ₀ + q ₆ ) / 2 by appropriately setting the transmittance _TL1 of the dimming unit 8a, the exposure amount of the composite exposure area _AC with respect to the exposure amount of the single exposure area _AS Since the amount of fluctuation is ΔQ / 2, exposure unevenness is minimized. Therefore, it is more preferable to set the transmittance _TL1 of the dimming unit 8a so that Q = (q ₀ + q ₆ ) / 2.
In this way, when the unevenness of the exposure amount of the composite exposure area _AC with respect to the exposure amount of the single exposure area _AS is reduced, the exposure unevenness caused by the seam of the exposure area is reduced. As a result, 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 a plurality of projection optical systems arranged in a staggered pattern are used, it is possible to reduce the exposure unevenness caused by the seam of the exposure region.

[Second Embodiment]
The 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 transmittance reducing member used in the exposure apparatus according to the second embodiment of the present invention. FIG. 14 is a schematic graph showing the transmittance distribution along the DD line in FIG. In the graph of FIG. 14, the horizontal axis represents the position in the X direction, and the vertical axis represents the transmittance. FIG. 15 is a schematic graph illustrating the integrated light amount in the 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 intensity.

As shown in FIGS. 1 and 2, the exposure apparatus 110 of the present embodiment includes a projection optical unit 15 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 15 includes a light attenuation filter 18 (light transmittance attenuation member) instead of the light attenuation filter 8 of the projection optical unit 5 in the first embodiment.
Hereinafter, the points different from the first embodiment will be mainly described.

As shown in FIG. 6, the light attenuation filter 18 is the same as the light attenuation filter 8 in the first embodiment, and is the lens of the first row projection optical system 5A and the second row projection optical system 5B in the projection optical unit 15. It is arranged at the lower end of the lens barrel 5b. The position of each light attenuation filter 18 with respect to the lens 5a is fixed by a filter holder 9 fixed to the lower end of the lens barrel 5b.
The light attenuation filter 18 is an exposure light L _2A (L _2B ) transmitted through the first-row projection optical system 5A (second-row projection optical system 5B), and the exposure light L _15A (L) in which at least a part of the light amount is reduced. Convert to _15B ).
The exposure light L _15A (L _15B ) irradiates the light amount correction region M ₂ (see FIG. 13) described later on the exposed body 6. Here, the light amount correction region M ₂ on the exposed body 6 is a region that overlaps with at least the single aperture region r _S in a plan view. In the present embodiment, as an example, the light amount correction region M ₂ is a region that overlaps a part of each composite aperture region r _C adjacent to both ends of the single aperture region r _S and the single aperture region r _S.

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

The dimming portion 18a is configured by extending both ends of the dimming portion 8a of the first embodiment outward in the X direction by less than 50% of the width of the composite opening region r _C in the X direction. In the example shown in FIG. 13, as an example, the dimming portion 18a is wider than the dimming portion 8a on both sides in the X direction by 25% of the width of the composite opening region r _C in the X direction.
The dimming portion 18a is a part of the entire single opening region r _S of the first opening 3A (second opening 3B) and a part of the composite opening region r _C on both sides in the X direction adjacent thereto in a plan view. (In FIG. 13, a quarter region of the composite opening region r _C ) is arranged so as to overlap each other.
The transmittance of the dimming section 18a is the same as that of the dimming section 8a in the first embodiment.

The light transmitting portion 8b in the present embodiment is formed in the region of the light attenuation filter 18 excluding the dimming portion 18a.

With such a configuration, the light attenuation filter 18 has a transmittance distribution as shown by the curve 204 in FIG. 14 in the X direction.
The reference numeral on the horizontal axis of FIG. 14 represents the position of the point of the same reference numeral on the DD line shown in FIG. The meanings of points a to h are the same as those described in the first embodiment. However, the point c'(f') is the midpoint of the line segment cd (ef).
The curve 204 has a minimum value TL1 between the points _c'and the point f', as in the dimming portion 8a in the first embodiment, and a constant value _Tmax 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 aperture 3 and the lens 5a by the light attenuation filter 18 having such a configuration is the exposure light light-attenuated according to the transmittance of the dimming portion 18a and the light transmission portion 8b. It is converted to L _15A (L _15B ).

According to the exposure apparatus 110, the 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 pass through the light attenuation filter 18. Therefore, the light amount distribution of the first light image (second light image) light image projected on the exposed body 6 by the exposure lights L _15A and L _15B is the first light image I _8A and the second light image I 8A. The operation of the exposure apparatus 100 is different from the light amount distribution of the light image I _8B .

FIG. 15 shows a graph of the integrated light amount when the exposed lights L _15A and L _15B scan on the exposed body 6. However, as in FIG. 12, FIG. 15 shows the integrated light amount at the time of scanning exposure when the transmittance T _max is 100% so as to be easily compared with the above-mentioned comparative example.
The symbols i to r on the horizontal axis of FIG. 15 represent the corresponding points of the points a to h of FIG. 13 on the exposed body 6. However, the positions corresponding to the points c'and f'are indicated by the symbols m'and n', respectively. The points j'and q'represent the positions corresponding to the points f'and c'of the dimming unit 8a arranged in the second row projection optical system 5B adjacent to the first row projection optical system 5A.
Therefore, the section from the point j to the point m and the section from the point n to the point q are each a composite exposure region _AC that overlaps with the composite aperture region r _C in a plan view. The section from the point m to the point n is a single exposure region _AS that overlaps with the single aperture region r _S in a plan view.
In the present embodiment, the light amount correction region M ₂ irradiated with the transmitted light of the dimming portion 18a of the light attenuation filter 18 is a region overlapping the entire single aperture region r _S and a composite aperture region r _C on both sides in the X direction thereof. It consists of an area that overlaps with a quarter of.
Curve 205 (see solid line) in FIG. 15 shows the integrated light amount in this embodiment, and curve 203 (see one-dot chain line) shows the integrated light amount in the comparative example. Curve 206 (see broken line) shows the amount of light attenuation due to the action of each light attenuation filter 18.

As shown in the curve 206, the integrated light amount in the present embodiment decreases at a constant rate in the range of the light amount correction region _M2 , so that the integrated light amount of the comparative example represented by the curve 203 is the whole. Decreases. On the graph, the integrated light amount of the comparative example moves downward in parallel. For example, the integrated light intensity from the point m to the point n decreases from q ₀ to Q. Similarly, the amount of light in each region of point j to point j', point m'to point m, point n to point n', and point q to point q'decreases below the light amount Q from point m to point n. ..
Therefore, as shown in the curve 205, the integrated light intensity in the present embodiment is Q (however, q ₆ <Q <q ₀ ) in the single exposure region _AS , and q ₆ to Q in the combined exposure region _AC . The light amount distribution that oscillates between them is shown.
According to the light attenuation filter 18 in the present embodiment, the transmittance _TL2 and the rate of change in the transmittance of the first dimming section 18a and the second dimming section 18b are appropriately set to increase the integrated light amount. The magnitude of the total fluctuation width Qq ₆ can be made smaller than the total fluctuation width ΔQ of the integrated light amount of the comparative example.
As described above, in the present embodiment, the total variation width Qq ₆ itself of the integrated light amount can be reduced as compared with the comparative example. Further, since the magnitude of the unevenness of the exposure amount in the composite exposure region _AC is also reduced, the exposure unevenness caused by the seam of the exposure region is reduced. As a result, 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 the present embodiment, when a plurality of projection optical systems arranged in a staggered pattern are used, it is possible to reduce the exposure unevenness caused by the seam of the exposure region.

[Third Embodiment]
The 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 transmittance reducing member used in the exposure apparatus according to the third embodiment of the present invention. FIG. 17 is a schematic graph showing the transmittance distribution along the line EE in FIG. In the graph of FIG. 17, the horizontal axis represents the position in the X direction, and the vertical axis represents the transmittance. FIG. 18 is a schematic graph illustrating the integrated light amount 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 intensity.

As shown in FIGS. 1 and 2, the exposure apparatus 120 of the present 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 transmittance attenuation member) instead of the light attenuation filter 8 of the projection optical unit 5 in the first embodiment.
Hereinafter, the points different from the first embodiment will be mainly described.

As shown in FIG. 6, the light attenuation filter 28 is the same as the light attenuation filter 8 in the first embodiment, and is the 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 attenuation filter 28 with respect to the lens 5a is fixed by a filter holder 9 fixed to the lower end of the lens barrel 5b.
The light attenuation filter 28 is an exposure light L _2A (L _2B ) transmitted through the first-row projection optical system 5A (second-row projection optical system 5B), and the exposure light L _25A (L) in which at least a part of the light amount is reduced. Convert to _25B ).
The exposure light L _25A (L _25B ) irradiates the light amount correction region _M2 (see FIG. 16) on the exposed body 6 in the same manner as in the second embodiment.

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

The first dimming unit 18a is a portion that attenuates the exposure light L _2A (L _2B ) transmitted through the field diaphragm 3 and the lens 5a with a constant transmittance TL ₃ . The first dimming section 18a is formed in the same manner as the dimming section 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 diaphragm 3 and the lens 5a in the first light amount correction region m ₁ in the first opening 3A (second opening 3B). It is a part that gradually attenuates in the positive direction in the X direction in the range from the rate T _max to TL ₃ .
The third dimming unit 28c transmits the exposure light L _2A (L _2B ) transmitted through the field diaphragm 3 and the lens 5a in the second light amount correction region m ₁ in the first opening 3A (second opening 3B). It is a part that gradually attenuates in the negative direction in the X direction in the range from the rate T _max to TL ₃ .

The rate of change in the transmittance in the second dimming section 28b and the third dimming section 28c is set based on, for example, an experiment, a simulation, or the like, as necessary for the light amount correction in the light amount correction region _M2 . The rate of change in transmittance in the second dimming section 28b and the third dimming section 28c may be constant (linear change) or may change based on an appropriate function. The rate of change in transmittance may be monotonic or non-monotonic. Moreover, changes in transmittance are not limited to smooth changes. For example, the transmittance may change in steps.

With such a configuration, the light attenuation filter 28 has a transmittance distribution as shown by the curve 207 in FIG. 17 in the X direction.
The reference numeral on the horizontal axis of FIG. 17 represents the position of the point of the same reference numeral on the line EE shown in FIG. The meanings of points a to h are the same as those described in 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 a constant value TL ₃ is taken from the point d to the point e. In the curve 207, the transmittance gradually increases from the point e to the point f, and T _max is taken at the point f. The curve 207 takes a constant value T _max at other positions.

The light attenuation filter 28 may be manufactured, for example, by depositing a metal thin film on the surface of the glass substrate to be 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 aperture 3 and the lens 5a by the light attenuation filter 28 having such a configuration is the first dimming section 28a, the second dimming section 28b, and the third dimming section 28c. , And the exposure light L _25A (L _25B ) light-attenuated according to the transmittance of the light transmitting portion 18c. The transmittance TL ₃ is selected from a 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, the 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 pass through the light attenuation filter 28. Therefore, the light amount distribution of the first light image (second light image) light image projected on the exposed body 6 by the exposure lights L _25A and L _25B is the first light image I _8A and the second light image I 8A. The operation of the exposure apparatus 100 is different from the light amount distribution of the light image I _8B .

FIG. 18 shows a graph of the integrated light amount when the exposed lights L _25A and L _25B scan on the exposed body 6. However, as in FIG. 12, FIG. 18 shows the integrated light amount at the time of scanning exposure when the transmittance T _max is 100% so as to be easily compared with the above-mentioned comparative example.
The symbols i to r on the horizontal axis of FIG. 18 represent the corresponding points of the points a to h of FIG. 16 on the exposed body 6.
Therefore, the section from the point j to the point m and the section from the point n to the point q are each a composite exposure region _AC that overlaps with the composite aperture region r _C in a plan view. The section from the point m to the point n is a single exposure region _AS that overlaps with the single aperture region r _S in a plan view.
Curve 208 (see solid line) in FIG. 18 shows the integrated light amount in this embodiment, and curve 203 (see one-dot chain line) shows the integrated light amount in the comparative example. The curve 209 (see the broken line) shows the amount of light attenuation due to the action of each light attenuation filter 28.

As shown by the curve 208, the integrated light amount in the present embodiment is the comparative example represented by the curve 203 because _both the single exposure area _AS and the combined exposure area _AC are the light amount correction area M2. The integrated light amount decreases as a whole.
In the present embodiment, the transmittance _TL3 is set so that the integrated light amount of the _first light amount correction region m1 becomes _Q4 (however, _q6 < _Q4 < _q0 ) by the first dimming unit 28a. To.
Therefore, the maximum value Q ₃ of the integrated light amount in the second light amount correction region m ₂ by the second dimming unit 28b (third dimming unit 28c) satisfies _Q4 < _Q3 < _q0 . The minimum value of the integrated light amount in the second light amount correction region m ₂ is q ₆ .
As a result, since the total variation range of the integrated light amount shown in the curve 209 is Q ₃ -q ₆ <ΔQ, the variation range of the integrated light amount itself is reduced as compared with the comparative example.
Further, by appropriately setting the transmittance _TL 3, it is possible to set the value of Q ₄ , which is the integrated light amount in most of the single exposure regions _AC , to a value between Q ₃ and q ₆ . In this case, since the exposure unevenness with respect to the integrated light amount Q ₄ can be reduced to (Q ₃ + q ₆ ) / 2 (<ΔQ / 2) or less, the exposure unevenness caused by the seam of the exposed region is larger than that of the first embodiment. It will be further reduced. As a result, 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, in order to reduce the total variation width of the integrated light amount, there is a portion where the light amount is lower than the minimum integrated light amount of the comparative example, whereas the light attenuation filter of the present embodiment is generated. According to 28, the minimum value of the integrated light amount is the same as that of the comparative example. Therefore, according to the present embodiment, the relative decrease in the integrated light amount is smaller than that in the second embodiment.

As described above, according to the exposure apparatus 120 of the present embodiment, when a plurality of projection optical systems arranged in a staggered pattern are used, it is possible to reduce the exposure unevenness caused by the seam of the exposure region.

[Modification example]
Next, in the present embodiment, a specific modification that can further reduce the exposure unevenness will be described.
FIG. 19 is a schematic graph showing the transmittance distribution of the light transmittance reducing member of the exposure apparatus of the modified example 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 illustrating the integrated light amount in the exposure of the exposure apparatus of 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 intensity.

This modification differs from the third embodiment only in the setting of the transmittance by the light attenuation filter 28.
As shown in FIG. 19, in this modification, the transmittance _TL3 of the first dimming unit 28a is set to a size that allows the integrated light amount in the single exposure region _AS to be set to _q6 .
In this modification, the transmittance of the second dimming section 28b (third dimming section 28c) is from point d so as to offset the decrease in the effective integrated light amount of the comparative example in the composite exposure region _AC . Point c (from point e to point f, the transmittance is set to be gradually increased from TL ₃ to T _max .
As for the correction effect of the integrated light amount in the light attenuation filter 28 of this modification, the curve 203 (see the alternate long and short dash line) showing the integrated light amount of the comparative example is inverted in the vertical direction as shown in the curve 209 (see broken line) in FIG. It is represented by a curved line that looks like it was made to.
As a result, the effective integrated light amount of the exposure light transmitted through the light attenuation filter 28 of this modification has a constant value _q6 as shown by the curve 208 (see the solid line) in FIG.
As described above, according to this modification, it is possible to remove the exposure unevenness 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 an exposed portion) are fixed, and the photomask for exposure and the exposed object (hereinafter referred to as an exposed object) are fixed. An example of a case where scanning exposure is performed by moving (referred to as) has been described. However, in the scanning exposure, the exposed portion and the object to be exposed may be relatively moved in the scanning direction (Y direction, the first direction), and the relative scanning may be performed. Therefore, in the exposure apparatus, the exposed portion may move in the scanning direction and the exposed object may be fixed. Further, in the exposure apparatus, the exposed portion and the exposed object may be moved respectively.

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 may be directions that intersect 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 case where the photomask 1 is moved by the first driving unit 10 and the exposed body 6 is moved by the second driving unit 11 moving 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 above embodiments, the case where the field diaphragms 3 and 4 are composed of one aperture that overlaps the entire projection optical system has been described. However, the field diaphragms 3 and 4 are configured by a combination of two or more apertures as long as an opening is formed in the range of NA of the projection optical system and light other than the light transmitted through the opening is not incident on the projection optical system. May be done.

In the description of each of the above embodiments, an example has been described in which the light transmittance reducing member is arranged between the projection optical system and the exposed object. However, the light transmittance reducing member may be arranged at any position as long as it is between the light source and the exposed object.

In the description of the first embodiment, the case where the projection optical unit 5 exposes the entire width of the exposed body 6 in the X direction has been described. However, if the exposure pattern of the exposed body 6 can be exposed by a single photomask 1, the projection optical unit 5 may have a size that covers a part in the X direction. In this case, the entire exposed body 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.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments. It is possible to add, omit, replace, and make other changes to the configuration without departing from the spirit of the present invention.
Further, the present invention is not limited by the above description, but is limited only by the appended claims.

1 Photomask (photomask for exposure)
2 Illumination light source (light source)
3, 4 Field diaphragm (aperture member)
3A, 4A 1st opening (opening)
3B, 4B 2nd 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 Exposed object (exposed object)
8, 18, 28 Light Attenuation Filter (Light Transmittance Attenuation Member)
8a, 18a Dimming part (uniform density filter)
28a 1st dimming part (1st light transmitting amount reducing part, uniform density filter)
28b Second dimming section (second light transmittance reducing section, gradient density filter)
28c Third dimming section (second light transmittance reducing section, gradient density filter)
100, 110, 120 Exposure device _AC Composite exposure area _AS , _AS1 , _AS2 Single exposure area I _5A , I _8A First light image I _5B, I _8B Second light image L _2A , L _2B , L _5A , L _5B , L _15A , L _15B , L _25A , L _25B , exposure light M ₁ , M ₂ light amount correction area m ₁ first light amount correction area m ₂ second light amount correction area O ₃ , O ₄ axis line ( Second axis)
O ₅ axis (first axis)
P mask pattern r _C composite opening area r _S single opening area

Claims (2)

A light source that generates exposure light and
Along the second axis so that the opening amount in the first direction along the first axis is constant in the second direction along the second axis intersecting the first axis in plan view. A plurality of staggered openings are formed, and two of the plurality of openings are adjacent to each other with a gap in the first direction, and the plurality of openings in the first direction. A single aperture region opened by one of them is alternately formed in the second direction, and the plurality of openings are arranged so as to be located between the light source and the photomask for exposure. Aperture member and
A plurality of projection optical systems arranged so as to face each of the plurality of openings of the diaphragm member and projecting an optical image of the exposure light transmitted through each of the plurality of openings onto an object to be exposed.
Of the exposed light, which is arranged on the optical path of the exposed light between the light source and the exposed object and is applied to the light amount correction region on the exposed object which overlaps with at least the single opening region in a plan view. A member that reduces the amount of light transmitted and a member that reduces the amount of light
Equipped with
The light transmittance reducing member is
It consists of a uniform density filter that uniformly reduces the transmittance of the exposure amount, and measures the amount of light of the exposure light to be applied to the first light amount correction region on the exposure object that overlaps at least the single opening region in a plan view. The first light transmittance reducing unit to be reduced, and
It comprises a gradient density filter in which the transmittance of the exposure amount increases as the distance from the portion adjacent to the first light transmittance reducing portion in the second direction increases, and the first light transmission amount reducing portion and the second light transmission amount reducing portion. A second light transmittance reduction that reduces the amount of light of the exposure light that is provided adjacent to each other in the direction of the above and is applied to the second light amount correction region on the exposure object that overlaps the front composite opening region in a plan view. Department and
An exposure apparatus. The light transmittance reducing member is
Arranged between the projection optical system and the exposure object ,
The exposure apparatus according to claim 1 .

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