JP6039292B2 - Exposure apparatus and article manufacturing method - Google Patents

Description

The present invention relates to an exposure apparatus and an article manufacturing method .

  When manufacturing a liquid crystal display device using a photolithography technique, a projection exposure apparatus is used that transfers a pattern formed on a mask to a glass substrate via a projection optical system. In recent years, the projection exposure apparatus is required to expand the exposure area in order to cope with an increase in size and cost of a liquid crystal display device.

  As a technique for expanding the exposure area, for example, a so-called joint exposure method using a plurality of projection optical systems has been proposed. As a projection exposure apparatus using a continuous exposure method, a scanning projection exposure apparatus described in Patent Document 1 is known. The projection exposure apparatus of Patent Document 1 includes a plurality of projection optical systems arranged in parallel along the non-scanning direction, and the ends of adjacent transfer patterns among the plurality of transfer patterns formed on the substrate by the plurality of projection optical systems. By overlapping the parts with each other, the exposure area is expanded as a whole. In Patent Document 1, the first scanning exposure is performed using a plurality of projection optical systems, and then the substrate is stepped in the non-scanning direction to perform the second scanning exposure. By overlapping the end portions of the transfer pattern formed by the first and second scanning exposures, the exposure area is further expanded.

JP 2009-163133 A

  When the transfer patterns formed by the adjacent projection optical systems are overlapped, if the relative positional deviation amount of the transfer pattern in the overlapping region is large, the transfer accuracy of the transfer pattern obtained by the overlay is deteriorated. One of the causes of the displacement of the transfer pattern is the telecentricity or asymmetric aberration of the projection optical system.

  Usually, the projection optical system is designed so that the tilt angle of the telecentricity of the light applied to the substrate is approximately 0 °, that is, the principal ray is substantially perpendicular to the substrate. However, since the number of optical elements that can be mounted on the projection optical system is limited by the size and cost of the apparatus, residual components that cannot be sufficiently corrected in design remain. This residual component causes a displacement of the transfer pattern due to the defocusing of the substrate, and the direction of the displacement is determined by the falling direction of the telecentricity of the light irradiated on the substrate. When adjacent projection optical systems have the same configuration, the telecentricity tilt direction of the light irradiated onto the substrate via these projection optical systems is both directed toward the optical axis of the projection optical system, or both. The direction is away from the optical axis of the projection optical system. For this reason, in the overlapping region, the positional shift caused by the defocus of the substrate of the transfer pattern formed by one projection optical system is opposite to the positional shift caused by the defocus of the transfer pattern formed by the other projection optical system. Will occur in the direction. That is, the relative displacement amount between adjacent transfer patterns is an amount obtained by adding the absolute values of the displacement amounts of the respective transfer patterns.

  The same applies to asymmetric aberrations (coma aberration, distortion, lateral chromatic aberration) of the projection optical system. When adjacent projection optical systems have the same configuration, the coma aberration of both projection optical systems is outward or the coma aberration of both projection optical systems is inward. Further, the distortion aberration of both projection optical systems is positive (pincushion type), or the distortion aberration of both projection optical systems is negative (barrel type). The lateral chromatic aberration of both projection optical systems is positive, or the lateral chromatic aberration of both projection optical systems is negative. For this reason, in the overlapping region, a displacement due to asymmetric aberration of the transfer pattern formed by one projection optical system and a displacement due to asymmetric aberration of the transfer pattern formed by the other projection optical system occur in opposite directions. End up.

  In Patent Document 1, when the pattern width in the non-scanning direction of the transfer pattern formed at the first time and the second time is appropriately changed, the projection optical system corresponding to the first and second overlapping regions is changed each time. It is described that pattern unevenness occurs in the overlapping region. In order to reduce the unevenness of the pattern, the image plane position, the focus position, and the magnification of each projection optical system are adjusted so that the positional deviation of the transfer pattern in the first and second overlapping regions is within an allowable range. . Specifically, two parallel flat glass plates are tilted to shift the image plane in a direction parallel to the surface of the substrate, and the wedge prism is rotated around the optical axis to change the focus position. Is moved in the direction along the optical axis to change the magnification of the pattern image.

  However, Patent Document 1 does not consider the telecentricity or asymmetric aberration of adjacent projection optical systems. As described above, since these optical characteristics have residual components that are difficult to remove by design, the relative displacement of the amount obtained by adding the absolute values of the displacement amounts of the adjacent transfer patterns in the overlapping region. Will occur. This relative misalignment may be small enough to satisfy the performance of the apparatus, but it is desired to make it smaller as the demand for improving the performance of the apparatus increases.

  The present invention has been made in view of the above-described points, and reduces the amount of relative displacement of a transfer pattern formed by an adjacent projection optical system in an overlapping region, and accurately transfers an original pattern. It is an object.

An exposure apparatus according to an aspect of the present invention includes a plurality of projection optical systems that project a pattern of an original onto a substrate, and illuminates the original while moving the original and the substrate in a scanning direction, thereby the plurality of projection optics. An exposure apparatus that exposes the substrate by projecting a plurality of pattern images by a system, wherein the plurality of projection optical systems includes a first projection optical system that projects a first pattern image on the substrate, and the substrate A second projection optical system for projecting a second pattern image onto the first pattern image and the second pattern image, the first pattern image and the second pattern image being moved while moving the original and the substrate in the scanning direction. An area on the substrate exposed by the image and an area on the substrate exposed by the second pattern image are projected on the substrate so as to have an overlapping area, and the overlapping area is projected onto the overlapping area. The first projection optical system is displaced by the telecentricity of the first projection optical system from the best focus position, and the first projection image is displaced in the direction perpendicular to the scanning direction. The first projection so that the positional deviation of the second pattern image in the direction perpendicular to the scanning direction generated at the same defocus position as the defocused position by the telecentricity of the system is in the same direction. The configuration of the optical element of the optical system and the configuration of the optical element of the second projection optical system are different optical designs .
An exposure apparatus according to another aspect of the present invention includes a plurality of projection optical systems that project an original pattern onto a substrate, and illuminates the original while moving the original and the substrate in a scanning direction. An exposure apparatus that projects a plurality of pattern images by a plurality of projection optical systems to expose the substrate, wherein the plurality of projection optical systems project a first pattern image onto the substrate. And a second projection optical system that projects a second pattern image onto the substrate, the first pattern image and the second pattern image being moved while moving the original and the substrate in the scanning direction. The region on the substrate exposed by the first pattern image and the region on the substrate exposed by the second pattern image are projected onto the substrate so as to have overlapping regions, and the front In the overlapping region, the scanning caused by the positional deviation of the first pattern image in the direction perpendicular to the scanning direction caused by the asymmetric aberration of the first projection optical system and the asymmetric aberration of the second projection optical system. The configuration of the optical element of the first projection optical system and the configuration of the optical element of the second projection optical system so that the positional deviation of the second pattern image in the direction perpendicular to the direction is the same. Are different in optical design from each other.

  In the present invention, the relative displacement of adjacent transfer patterns is reduced by setting the direction of displacement of adjacent transfer patterns in the overlapping region to be the same in the non-scanning direction or the scanning direction. Thereby, in the overlapping region, the relative positional deviation of the transfer pattern formed by the adjacent projection optical system can be reduced, and the original pattern can be transferred with high accuracy.

1 is a schematic perspective view of a projection exposure apparatus to which the present invention can be applied. The front view which shows projection optical system PL1, PL2. The figure which shows projection area | region PA1-PA5 on the glass substrate P. FIG. The schematic diagram which shows the incident state to the superimposition area | region of light m1, m2 via projection optical system PL1, PL2.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic perspective view of a scanning projection exposure apparatus 100 to which the present invention can be applied. The projection exposure apparatus 100 includes a mask stage that holds a mask M (original), a substrate stage that holds a glass substrate P (substrate), and an illumination optical system (illumination means) LO that illuminates the mask M. Furthermore, a projection optical system PO that transfers a projection image of the pattern formed on the mask M onto the glass substrate and forms a transfer pattern as a latent image on the glass substrate P is provided. A photosensitive agent (resist) is applied on the glass substrate P, and a transfer pattern is formed in the photosensitive agent. In the following description, the axis along the scan is the X axis, the axis perpendicular to the X axis in the plane of the glass substrate P (in the horizontal plane in the present embodiment) is the Y axis, and the axis along the normal line of the glass substrate is The Z axis is assumed.

  The projection exposure apparatus 100 is formed on the mask M by irradiating the light through the mask M and the projection optical system PO onto the glass substrate P while scanning the mask M and the glass substrate P with respect to the projection optical system PO. The pattern is transferred onto the glass substrate P. The projection optical system PO is composed of a plurality of projection optical systems PO1 to PO5 arranged in parallel. The patterns formed on the original plate are transferred onto the glass substrate P by overlapping the ends of adjacent transfer patterns among the plurality of transfer patterns formed on the glass substrate P by the plurality of projection optical systems PO1 to PO5. .

  Light from the light source 1 is guided to the illumination optical system (illuminating means) LO through the optical fiber 2. For example, a mercury lamp is used as the light source 1. The illumination optical system LO is composed of a plurality of illumination optical systems LO1 to LO5. Each illumination optical system includes a condenser lens, a fly-eye lens, and the like, and is configured to illuminate the mask M with light having a uniform illuminance distribution. Further, each illumination optical system includes a light shielding plate that shields a part of the light from the light source 1, and an arcuate (arc slit shaped) illumination region is formed by the action of the arc shaped slit of the light shielding plate. That is, the mask M is configured to be illuminated by arc-shaped illumination light from the arc-shaped slit. In this embodiment, an Offner optical system is employed as the projection optical system, and a favorable imaging performance is obtained in the Offner optical system by using an arcuate illumination region. The shape of the illumination area and the illumination light may be appropriately set according to the configuration of the optical system, and may be, for example, a trapezoidal shape.

  Light from the plurality of illumination optical systems LO1 to LO5 illuminates the plurality of illumination areas MA1 to MA5 on the mask M and is guided onto the glass substrate P (substrate) via the plurality of projection optical systems PO1 to PO5. . The plurality of projection optical systems PO1 to PO5 are juxtaposed along the Y-axis direction (non-scanning direction), and adjacent projection optical systems are arranged apart from each other in the X-axis direction (scanning direction). By disposing the projection optical systems PL1, PL3, and PL5 and the projection optical systems PO2 and PO4 in an inverted manner, physical interference between the projection optical systems can be prevented, and the ends of adjacent transfer patterns can be overlapped with each other. it can. In accordance with the arrangement of the projection optical systems PO1 to PO5, the outer peripheral shapes of the illumination areas MA1, MA3, and MA5 on the mask M are formed by inverting the outer peripheral shapes of the illumination areas MA2 and MA4.

  FIG. 2 is a front view showing the projection optical systems PO1 and PO2. The projection optical system PO1 has a configuration in which Offner optical systems are arranged in two stages along the Z-axis. The upper Offner optical system includes a mirror unit 11 that guides light from the mask M to the concave mirror 12 and guides light through the concave mirror 12 and the convex mirror 13 to the lower Offner optical system. The lower Offner optical system includes a mirror unit 21 that guides light from the upper Offner optical system to the concave mirror 22 and guides light through the concave mirror 22 and the convex mirror 23 to the glass substrate P. Furthermore, the projection optical system PO1 includes a plurality of optical elements for correcting aberrations. Since the projection optical systems PO3 and PO5 are the same optical system as the projection optical system PO1, description thereof will be omitted.

  The projection optical system PO2 has a configuration in which Offner optical systems are arranged in two stages along the Z axis. The upper Offner optical system includes a mirror unit 31 that guides light from the mask M to the concave mirror 32 and guides light through the concave mirror 32 and the convex mirror 33 to the lower Offner optical system. The lower Offner optical system includes a mirror unit 41 that guides light from the upper Offner optical system to the concave mirror 42 and guides light through the concave mirror 42 and the convex mirror 43 to the glass substrate P. Furthermore, the projection optical system PO1 includes a plurality of optical elements for correcting aberrations. Since the projection optical system PO4 is the same optical system as the projection optical system PO2, description thereof is omitted. Since the projected image of the pattern reversed by the upper Offner optical system is reversed again by the lower Offner optical system, the pattern formed on the mask M can be directly transferred onto the glass substrate P.

  FIG. 3 is a diagram showing projection areas PA1 to PA5 on the glass substrate P. As shown in FIG. The projection areas PA1 to PA5 correspond to the projection optical systems PO1 to PO5. By causing the substrate to scan, the projection areas PA1 to PA5 move on the glass substrate 1 in the direction of the arrow. Therefore, the projection optical system PO1 forms a transfer pattern in the region between the two broken lines shown in the figure, and the projection optical system PO2 forms a transfer pattern in the region between the two alternate long and short dash lines. The overlapping area OA is an area where adjacent transfer patterns overlap on the glass substrate P. In the following description, the projection optical systems PO1 (first projection optical system) and PO2 (second projection optical system) will be described as adjacent projection optical systems, but other adjacent projection optical systems (for example, projection) The same applies to the optical systems PO2 and PO3), and a description thereof will be omitted.

  FIGS. 4A and 4B are schematic views showing the incident state of the light m1 and m2 on the overlapping region via the projection optical systems PO1 and PO2. 4A, the horizontal axis is the X axis and the vertical axis is the Z axis, and in FIG. 4B, the horizontal axis is the Y axis and the vertical axis is the Z axis. As described above, the illumination light (first illumination light, second illumination light) from the illumination optical systems LO1 and LO2 is applied to the mask M, and is applied to the glass substrate P via the projection optical systems PL1 and PO2. The

  Ideally, the projection optical system is designed so that the tilt angle of the telecentricity of the light applied to the glass substrate P is approximately 0 °, that is, the principal ray is substantially perpendicular to the glass substrate P. However, it is difficult to set the tilt angle to 0 ° due to restrictions on the size and cost of the apparatus, and there is a residual component in optical design. Further, although it is sufficiently small with respect to the residual component in the optical design, it has a residual component due to manufacturing error. Therefore, the light m1 that has passed through the projection optical system PO1 and the light m2 that has passed through the projection optical system PO2 are applied to the overlapping region with a tilt angle with respect to the normal line of the glass substrate P. BP is a best focus position of the glass substrate P, and DP is a defocus position separated from the best focus position by a distance d. When the tilt angles of the light m1 and m2 in the XZ plane are θ1 and θ2, when the glass substrate P is defocused by the distance d, transfer pattern positional deviations ΔX1 and ΔX2 occur. Further, when the tilt angles of the light m1 and m2 in the YZ plane are θ3 and θ4, if the glass substrate P is defocused by the distance d, transfer pattern positional deviations ΔY1 and ΔY2 occur.

  In the present embodiment, the projection optical system PO1 is configured so that the light applied to the glass substrate P via the projection optical system PO1 falls in a direction away from the optical axis of the projection optical system PO1. Furthermore, the projection optical system PO2 is configured such that light irradiated onto the glass substrate P via the projection optical system PO2 falls in a direction toward the optical axis of the projection optical system PO2. That is, the telecentricities of the projection optical systems PO1 and PO2 are different from each other. Specifically, by changing at least one of the distance between the optical elements constituting the projection optical systems PO1 and PO2, the radius of curvature of the optical elements, and the thickness of the optical elements, the telecentric of the projection optical systems PO1 and PO2 is different. Cities are different from each other. Thereby, since it is not necessary to change the structure of projection optical system PO1 and PO2 significantly, manufacturing cost can be held down.

In the overlapping region, the falling directions of the lights m1 and m2 in the XZ plane are the same direction, and the falling directions of the lights m1 and m2 in the YZ plane are the same direction. By making the tilt directions of the light m1 and m2 the same direction, the displacement of adjacent transfer patterns becomes the same direction (direction) , and the relative displacement of these transfer patterns is the difference between the absolute values of the two. Become. Therefore, even if there is a positional shift between the transfer patterns, the relative positional shift amount between them can be reduced.

  In addition to the above-described configuration, an adjustment mechanism that adjusts the position or tilt of a part of the optical elements that constitute the illumination optical system may be provided. By reducing the absolute values of the tilt angles θ1 and θ2 of the light applied to the glass substrate P using the adjustment mechanism, the relative positional deviation amount can be further reduced.

  As described above, according to the present embodiment, it is possible to reduce the relative displacement of the transfer pattern formed by the adjacent projection optical system in the overlapping region, and to accurately transfer the original pattern.

(Second Embodiment)
In the first embodiment, the optical characteristic related to the telecentricity of the adjacent projection optical system has been described. In the present embodiment, the optical characteristic related to the asymmetric aberration of the adjacent projection optical system will be described. The schematic configuration of the exposure apparatus is the same as that shown in FIGS. In the following description, the projection optical systems PO1 (first projection optical system) and PO2 (second projection optical system) will be described as adjacent projection optical systems, but other adjacent projection optical systems (for example, projection) The same applies to the optical systems PO2 and PO3), and a description thereof will be omitted.

  In the present embodiment, the projection optical system PO1 is configured to have a positive (pincushion type) distortion, and the projection optical system PO2 has a negative (barrel type) distortion. That is, the optical characteristics regarding the distortion aberration of the projection optical systems PO1 and PO2 are different from each other. For this reason, in the overlapping region in FIG. 3, the displacement of the transfer pattern due to distortion of the projection optical system PO1 occurs in the −Y direction, and the displacement of the transfer pattern due to distortion of the projection optical system PO2 occurs in the −Y direction. Occur. That is, the relative positional deviation amount of these transfer patterns is the difference between the absolute values of both. Therefore, even if there is a positional shift between the transfer patterns, the relative positional shift amount between them can be reduced.

  Instead of distortion, the chromatic aberration of magnification of the projection optical systems PO1 and PO2 may be different from each other. In this case, for example, the projection optical system PO1 has positive lateral chromatic aberration, and the projection optical system PO2 has negative lateral chromatic aberration. Further, the coma aberration of the projection optical systems PO1 and PO2 may be made different from each other in place of the distortion aberration. In this case, for example, the projection optical system PO1 has outward coma, and the projection optical system PO2 has inward coma. In the present specification, the shift in the line width of adjacent transfer patterns in the overlapping region is also referred to as the position shift of the transfer pattern.

To vary the asymmetric aberration of the projection optical system PO1, PO2, in the present embodiment, the distance between the optical elements constituting the projection optical system PO1, PO2, the radius of curvature of the optical element, any of at least the thickness of the optical element They are different from each other. Thereby, since it is not necessary to change the structure of projection optical system PO1 and PO2 significantly, manufacturing cost can be held down.

  In the first and second embodiments, the direction of displacement of each transfer pattern determined by the telecentricity or asymmetric aberration of adjacent projection optical systems in the overlapping region is the same in the non-scanning direction and the scanning direction. Yes. Depending on the required apparatus performance, only one of the non-scanning direction and the scanning direction may be set to the same direction. Further, the projection exposure apparatus is not limited to an apparatus for manufacturing a liquid crystal display device. For example, the present invention can be applied to an apparatus for manufacturing a semiconductor device.

  Next, a method for manufacturing a device (semiconductor device, liquid crystal display device, etc.) according to an embodiment of the present invention will be described. A semiconductor device is manufactured through a pre-process for producing an integrated circuit on a wafer and a post-process for completing an integrated circuit chip on the wafer produced in the pre-process as a product. The pre-process includes a step of exposing a wafer coated with a photosensitive agent using the above-described exposure apparatus, and a step of developing the wafer. The post-process includes an assembly process (dicing and bonding) and a packaging process (encapsulation). A liquid crystal display device is manufactured through a process of forming a transparent electrode. The step of forming the transparent electrode includes a step of applying a photosensitive agent to a glass substrate on which a transparent conductive film is deposited, a step of exposing the glass substrate on which the photosensitive agent is applied using the above-described exposure apparatus, and a glass substrate. The process of developing is included. According to the device manufacturing method of the present embodiment, it is possible to manufacture a higher quality device than before.

  As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

Claims (12)

Comprising a plurality of projection optical system for projecting a pattern of an original onto a substrate, wherein the original and while moving by illuminating the original by projecting a plurality of pattern images by the plurality of projection optical system said substrate in a scanning direction An exposure apparatus that exposes the substrate ,
The plurality of projection optical systems includes: a first projection optical system that projects a first pattern image on the substrate; and a second projection optical system that projects a second pattern image on the substrate;
The first pattern image and the second pattern image are exposed by the region on the substrate exposed by the first pattern image and the second pattern image while moving the original and the substrate in the scanning direction. Projected onto the substrate so as to have overlapping regions overlapping with regions on the substrate,
In the overlapping region, a positional deviation of the first pattern image in a direction perpendicular to the scanning direction generated at a position defocused from a best focus position by the telecentricity of the first projection optical system, and the second and positional deviation of the second pattern image in the direction perpendicular to the scanning direction by the telecentricity occur at the same defocus position and position the defocus of the projection optical system, as but in the same direction, the An exposure apparatus characterized in that the configuration of the optical element of the first projection optical system and the configuration of the optical element of the second projection optical system have different optical designs . A plurality of projection optical systems for projecting the pattern of the original onto the substrate; and illuminating the original while moving the original and the substrate in the scanning direction to project a plurality of pattern images by the plurality of projection optical systems. An exposure apparatus that exposes the substrate,
The plurality of projection optical systems includes: a first projection optical system that projects a first pattern image on the substrate; and a second projection optical system that projects a second pattern image on the substrate;
The first pattern image and the second pattern image are exposed by the region on the substrate exposed by the first pattern image and the second pattern image while moving the original and the substrate in the scanning direction. Projected onto the substrate so as to have overlapping regions overlapping with regions on the substrate,
In the overlap region, the positional deviation of the first pattern image in the direction perpendicular to the scanning direction caused by the asymmetric aberration of the first projection optical system and the asymmetric aberration of the second projection optical system. The configuration of the optical element of the first projection optical system and the optical element of the second projection optical system so that the positional deviation of the second pattern image in the direction perpendicular to the scanning direction is the same. An exposure apparatus having an optical design different from each other in configuration. The structure of the optical element, the distance between the optical elements, the radius of curvature of the optical element, comprising at least one of the thickness of the optical element, that the exposure apparatus according to claim 1 or 2, characterized in. The positional deviation of the first pattern image and the second pattern image, an exposure apparatus according to any one of claims 1 to 3, characterized in that also in the same direction in the scanning direction. 5. The projection area formed by the first projection optical system on the substrate has a shape obtained by inverting the projection area formed by the second projection optical system. 6. The exposure apparatus described in 1. 6. The exposure apparatus according to claim 5 , wherein the shape of the projection area includes an arc or a trapezoid. Wherein the plurality of projection optical systems each comprise a convex mirror and the concave mirror, the first projection optical system and the second projection optical system according to claim 5 or, characterized in that it is arranged inverted with each other 6. The exposure apparatus according to 6 . The asymmetrical aberration includes distortion,
The exposure according to any one of claims 1 to 7, wherein the first projection optical system has a positive distortion, and the second projection optical system has a negative distortion. apparatus. The asymmetrical aberration includes lateral chromatic aberration;
The exposure according to any one of claims 1 to 7, wherein the first projection optical system has positive lateral chromatic aberration, and the second projection optical system has negative lateral chromatic aberration. apparatus. The asymmetrical aberration includes coma,
The first projection optical system has outward coma, and the second projection optical system has inward coma. Exposure equipment. A first illumination optical system and a second illumination optical system for illuminating the original plate,
Illuminating the original with first illumination light from the first illumination optical system, and projecting an image of the pattern of the original on the substrate by the first projection optical system;
Illuminating the original with second illumination light from the second illumination optical system, and projecting an image of the pattern of the original on the substrate by the second projection optical system;
The first illumination optical system and the second illumination optical system adjust a position or inclination of an optical element that constitutes the illumination optical system, thereby adjusting a positional deviation between the first pattern image and the second pattern image. The exposure apparatus according to claim 1, wherein the exposure apparatus is reduced. A step of exposing a substrate using an exposure apparatus according to any one of claims 1 to 11,
Method of manufacturing an article, characterized in that it has a, a step of developing the substrate that is the exposure.

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