Illumination optical system, exposure device, and production method of article

Abstract

To provide an illumination optical system advantageous for evenly illuminating a surface to be illuminated.SOLUTION: An illumination optical system for illuminating a surface to be illuminated with light from a light source includes: an optical integrator arrayed with a plurality of optical elements; a filter arrayed with a plurality of light adjustment regions corresponding to a plurality of the respective optical elements; and an adjustment part for adjusting a revolution amount of the filter around an optical axis of the illumination optical system to the optical integrator, where each of a plurality of the light adjustment regions has a transmittance distribution where the transmittance varies toward a peripheral part from a center part of each of light adjustment regions, and the adjustment part adjusts a revolution amount of the filter so as to cancel out a variation with time of illuminance unevenness on the surface to be illuminated.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an illumination optical system, an exposure apparatus, and a method for manufacturing an article. [Background technology]

[0002] In a lithography process for manufacturing an article such as a semiconductor device, an exposure apparatus is used that has an illumination optical system for illuminating an original and a projection optical system for projecting a pattern of the original onto a substrate. The pattern of the original is transferred onto a resist arranged (coated) on the surface of the substrate. In an exposure apparatus, if the illumination optical system illuminates the original non-uniformly, the transfer of the pattern onto the resist may be poor. Therefore, an optical integrator for illuminating the original with a uniform illuminance is arranged in the illumination optical system. As an optical integrator, for example, a rod-type optical integrator and an optical integrator including a plurality of wavefront division elements arranged two-dimensionally are known.

[0003] Generally, the illuminance unevenness S is a value that indicates the non-uniformity of the illuminance on the illuminated surface, and the maximum illuminance on the illuminated surface is S max , the minimum value is S min Then, S = (S max -S min ) / (S max +S min By placing an optical integrator in the illumination optical system, it is possible to keep the illuminance unevenness S within a few percent.

[0004] On the other hand, the (internal) transmittance and anti-reflection coating of the optical elements used in the exposure apparatus change over time, so the transmittance of the optical elements changes symmetrically with respect to the center of the optical element from the center of the optical element, where the light density is high, to the periphery. This results in an illuminance distribution on the illuminated surface that is symmetric with respect to the optical axis.

[0005] Techniques for correcting such illuminance distribution have been proposed in the past (see Patent Documents 1 and 2). Patent Document 1 discloses a technique for correcting illuminance distribution by driving a lens arranged after an optical integrator in the optical axis direction to generate distortion. Patent Document 2 discloses a technique for correcting illuminance distribution by driving an optical filter arranged before an optical integrator in the optical axis direction to blur the amount of light adjustment. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-317348 [Patent Document 2] JP 2001-135564 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the conventional technology, in order to correct the illuminance distribution, a sufficient driving range is required in the illumination optical system to drive optical members such as optical elements and optical filters in the optical axis direction. Therefore, a space corresponding to the driving range for driving the optical members in the optical axis direction must be secured in the illumination optical system, which increases the size of the entire optical system and makes the illumination optical system expensive.

[0008] The present invention has been made in consideration of the above problems in the conventional technology, and has an exemplary object to provide an illumination optical system that is advantageous for uniformly illuminating a surface to be illuminated. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, an illumination optical system as one aspect of the present invention is an illumination optical system that illuminates an illuminated surface with light from a light source, and includes an optical integrator in which a plurality of optical elements are arranged, a filter in which a plurality of light intensity adjustment areas are arranged corresponding to each of the plurality of optical elements, and an adjustment unit that adjusts the amount of rotation of the filter around the optical axis of the illumination optical system relative to the optical integrator, wherein each of the plurality of light intensity adjustment areas has a transmittance distribution in which the transmittance changes from the center of each light intensity adjustment area toward the periphery, and the adjustment unit adjusts the amount of rotation of the filter so as to cancel out changes over time in illuminance unevenness on the illuminated surface.

[0010] Further objects or other aspects of the present invention will become apparent from the following description of the embodiments with reference to the accompanying drawings. Effect of the Invention

[0011] According to the present invention, for example, it is possible to provide an illumination optical system that is advantageous for uniformly illuminating a surface to be illuminated. [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic diagram showing a configuration of an exposure apparatus according to one aspect of the present invention. [Diagram 2] FIG. 2 is a schematic diagram illustrating a configuration of an optical filter. [Diagram 3] 5A and 5B are diagrams for explaining the transmittance distribution in a light amount adjustment region of the optical filter. [Figure 4] 1A and 1B are diagrams for explaining illuminance distributions at a microlens and a field stop of an optical integrator. [Diagram 5] 1A and 1B are diagrams for explaining illuminance distributions at a microlens and a field stop of an optical integrator. [Figure 6] 1A and 1B are diagrams for explaining the concept of changing the illuminance distribution on an illuminated surface by rotating an optical filter. [Figure 7]1A and 1B are diagrams for explaining the concept of changing the illuminance distribution on an illuminated surface by rotating an optical filter. [Figure 8] 6 is a flowchart for explaining a process of correcting a change over time in illuminance unevenness on an illuminated surface. [Figure 9] 5A and 5B are diagrams for explaining the transmittance distribution in a light amount adjustment region of the optical filter. [Figure 10] 11A and 11B are diagrams illustrating examples of the arrangement of light amount adjustment regions in which shielding portions are provided in an optical filter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0014] FIG. 1 is a schematic diagram showing a configuration of an exposure apparatus 100 according to one aspect of the present invention. The exposure apparatus 100 is a lithography apparatus used in, for example, a lithography process, which is a manufacturing process for semiconductor elements and the like, and forms a pattern on a substrate. The exposure apparatus 100 exposes a substrate W through an original R. In this embodiment, the exposure apparatus 100 is a step-and-repeat type exposure apparatus that transfers the pattern of the original R onto the substrate while the original R and the substrate W are stationary. However, the exposure apparatus 100 can also adopt a step-and-scan type that scans and exposes the substrate W while moving the original R and the substrate W in a scanning direction, or other exposure methods.

[0015] 1, the exposure apparatus 100 has an illumination optical system 101, an original driving unit 102, a projection optical system 103, a substrate driving unit 104, a measurement unit 105, and a control unit 106. In this embodiment, a coordinate system is defined in which an axis along the normal direction of the substrate W held by the substrate driving unit 104 is defined as the Z axis, and axes along directions perpendicular to each other in a plane parallel to the substrate W are defined as the X axis and the Y axis.

[0016] The illumination optical system 101 includes various optical elements, and illuminates the original R arranged on the illuminated surface (object surface of the projection optical system 103) using light (light beam) from the light source 1. The light source 1 includes, for example, an extra-high pressure mercury lamp that emits light such as i-line (wavelength 365 nm). However, the light source 1 is not limited to this, and may be a KrF excimer laser that emits light with a wavelength of 248 nm, an ArF excimer laser that emits light with a wavelength of 193 nm, or an F2 laser that emits light with a wavelength of 157 nm. The light source 1 may also be an EUV light source that emits extreme ultraviolet light (EUV light) with a wavelength of about 11 nm to 14 nm.

[0017] A pattern (e.g., a circuit pattern) to be transferred to the substrate W is formed on the original R. The original R is made of a material that transmits light from the light source 1 (illumination optical system 101), such as quartz glass as a base material. The original driving unit 102 includes, for example, a movable original stage that holds the original R, and an original driving mechanism that drives the original stage about the X-axis and Y-axis.

[0018] The projection optical system 103 projects the pattern of the original R illuminated by the illumination optical system 101 onto the substrate W. The projection optical system 103 includes an imaging optical system, the front focal point of which is located on a surface (position of the object plane) on which the original R is disposed, and the rear focal point of which is located on a surface (position of the image plane) on which the substrate W is disposed. In other words, the projection optical system 103 makes the position of the original R and the position of the substrate W optically conjugate with each other.

[0019] The substrate W is a substrate onto which the pattern of the original R is transferred, and has a resist (photosensitive material) on its surface. The substrate driving unit 104 includes a movable substrate stage that holds the substrate W, and a substrate driving mechanism that drives the substrate stage about the X-axis, Y-axis, and Z-axis (and their rotational directions ωx, ωy, and ωz).

[0020] The measuring unit 105 includes, for example, a light quantity sensor, and measures the illuminance distribution formed on the illuminated surface. In this embodiment, the measuring unit 105 is disposed on the image plane of the projection optical system 103, specifically, on the substrate stage constituting the substrate driving unit 104.

[0021] The control unit 106 is configured, for example, with a computer (information processing device) including a CPU, memory, etc. The control unit 106 comprehensively controls each unit of the exposure apparatus 100 in accordance with a program stored in a storage unit or the like to operate the exposure apparatus 100. The control unit 106 controls the exposure process in which the substrate W is exposed through the original R and various processes related to the exposure process.

[0022] The illumination optical system 101 will be described in detail below. The illumination optical system 101 includes a relay lens 3, a bending mirror M1, an optical integrator 4, a condenser lens 5, a field stop 6, an imaging lens 7, and a bending mirror M2. The relay lens 3 and the bending mirror M1 configure an illumination system 10, and the imaging lens 7 and the bending mirror M2 configure an imaging system 11. Light from the illumination system 10 enters the condenser lens 5 via the optical integrator 4.

[0023] The elliptical mirror 2 has a first focal point and a second focal point, and collects light from the light source 1 disposed at the first focal point at the second focal point. The relay lens 3 includes an imaging optical system, and its front focal point is disposed at the second focal point of the elliptical mirror 2, and its rear focal point is disposed at the entrance surface 41 of the optical integrator 4. In other words, the relay lens 3 makes the second focal point of the elliptical mirror 2 and the entrance surface 41 of the optical integrator 4 optically conjugate with each other.

[0024] In this embodiment, the illumination optical system 101 includes an illumination system 10 that makes the second focal point of the elliptical mirror 2 and the entrance surface 41 of the optical integrator 4 optically conjugate with each other, but may include an illumination system that does not have such a relationship. A wavelength filter (not shown) that blocks light in a specific wavelength range is disposed near the pupil plane of the relay lens 3, and the exposure wavelength (the wavelength of the light that exposes the substrate W) is determined by this wavelength filter.

[0025] The optical integrator 4 is configured as a so-called fly-eye lens, for example, in which a plurality of micro lenses (optical elements) are two-dimensionally arranged on a surface (incident surface 41) on the side of the light incident direction to form a plurality of secondary light sources. The incident surface 41 of the optical integrator 4 (each micro lens) is optically conjugate with the illuminated surface. The vicinity of the exit surface 42 of the optical integrator 4 corresponds to the pupil surface of the illumination optical system 101. An effective light source is formed on the exit surface 42 of the optical integrator 4. The fly-eye lens includes a cylindrical lens and a micro lens array, but may be replaced with an optical rod or a diffractive optical element.

[0026] The condenser lens 5 superimposes and illuminates the field stop 6 with the secondary light source formed by the optical integrator 4. The field stop 6 includes multiple movable shielding plates that form an arbitrary aperture shape, and limits the exposure range on the illumination surface, which is the position of the original R (and further, the position of the substrate W). The imaging lens 7 illuminates the original R with light having a shape corresponding to the aperture shape defined by the field stop 6.

[0027] In the exposure apparatus 100, for example, the (internal) transmittance and anti-reflection coating of the optical elements used in the illumination optical system 101 change over time, and so the illuminated surface experiences an illuminance distribution that is symmetric about the optical axis AX of the illumination optical system 101, i.e., a change in illuminance unevenness over time. Therefore, in this embodiment, in order to correct (control) the change in illuminance unevenness over time on the illuminated surface, an optical filter 8 and an adjustment unit 15 are disposed near the entrance surface 41 of the optical integrator 4.

[0028] 2 is a schematic diagram showing the configuration of the optical filter 8. In the optical filter 8, a plurality of light amount adjustment regions 20 corresponding to each of the plurality of micro lenses of the optical integrator 4 are arranged. In other words, the light amount adjustment regions 20 are arranged repeatedly in the same number as the number of micro lenses of the optical integrator 4. The size of the light amount adjustment regions 20 is equal to the size of the micro lenses of the optical integrator 4. Moreover, the plurality of light amount adjustment regions 20 are arranged rotationally symmetrically with respect to the optical axis AX (center of the optical filter 8) of the illumination optical system 101 in the XY plane of the optical filter 8.

[0029] 3 is a diagram for explaining the transmittance distribution in the light amount adjustment region 20 of the optical filter 8. The transmittance (distribution) in the light amount adjustment region 20 is adjusted for the microlenses of the optical integrator 4. As shown in FIG. 3, the light amount adjustment region 20 is expressed as follows: the center O of the light amount adjustment region is the origin, and the transmittance at the origin is T O [%], the transmittance changes continuously by ΔT [%] toward the periphery. Such a transmittance distribution is rotationally symmetrical with respect to the center O (origin) of each light amount adjustment region. FIG. 3 shows the transmittance distribution in the light amount adjustment region 20, where the transmittance in the periphery is the transmittance T at the origin. O , that is, a distribution that is convex from the center O of the light amount adjustment region 20 toward the periphery, but is not limited thereto. For example, the transmittance distribution in the light amount adjustment region 20 is such that the transmittance in the periphery is lower than the transmittance T O In other words, the distribution may be concave from the center O of the light amount adjustment region 20 toward the periphery.

[0030] The transmittance distribution in the light amount adjustment region 20 of the optical filter 8 can be realized, for example, by controlling the film thickness (film thickness distribution) of the antireflection film provided in the light amount adjustment region 20 within the plane. In general, the antireflection film optimizes the light interference condition by adjusting the total number, material, and thickness of the thin films in order to reduce the reflectance. Therefore, an arbitrary transmittance distribution can be formed by locally adjusting the thickness of the thin films within the plane of the light amount adjustment region 20 of the optical filter 8, that is, by partially changing the film thickness of the optical filter 8 and destroying the light interference condition. In this embodiment, the antireflection film provided in each of the multiple light amount adjustment regions 20 of the optical filter 8 has a film thickness distribution that is rotationally symmetrical with respect to the center of each light amount adjustment region. The film thickness of the antireflection film can be controlled (processed) by ion beam processing, etching processing, polishing with magnetic fluid, or the like.

[0031] In this embodiment, the optical filter 8 is disposed near the incident surface 41 of the optical integrator 4, but it is sufficient that the optical filter 8 is disposed between the light source 1 and the optical integrator 4 so as to be optically conjugate with the illuminated surface. For example, the optical filter 8 may be disposed near the second focal position of the elliptical mirror 2 which is optically conjugate with the incident surface 41 of the optical integrator 4. When the optical filter 8 is disposed near the second focal position of the elliptical mirror 2, the size of each light amount adjustment region 20 of the optical filter 8 needs to be adjusted by the optical magnification of the illumination system 10 from the size of the microlenses of the optical integrator 4.

[0032] Furthermore, when the illumination system 10 is not an imaging optical system but a Fourier transform optical system, the entrance surface 41 of the optical integrator 4 and the second focal position of the elliptical mirror 2 are not optically conjugate with each other. Therefore, in this case, it is necessary to place the optical filter 8 near the entrance surface 41 of the optical integrator 4.

[0033] The adjustment unit 15 includes a rotation mechanism that rotates the optical filter 8 around the optical axis AX of the illumination optical system 101 relative to the optical integrator 4. In this embodiment, the adjustment unit 15 realizes a function of adjusting the amount of rotation (rotation angle) of the optical filter 8 around the optical axis AX of the illumination optical system 101 relative to the optical integrator 4. The amount of rotation of the optical filter 8 to be adjusted by the adjustment unit 15 is controlled (determined) by the control unit 106.

[0034] The illuminance distribution at each of the microlenses of the optical integrator 4 and the field stop 6 will be described with reference to FIG. 4, FIG. 5(a), FIG. 5(b), FIG. 5(c) and FIG. 5(d). FIG. 4 shows a state in which the light passing through each of the light amount adjustment regions 20a, 20b and 20c of the optical filter 8 passes through each of the microlenses 41a, 41b and 41c of the optical integrator, and superimposes and illuminates the field stop 6 via the condenser lens 5. FIG. 5(a) shows the illuminance distribution at the microlens 41a of the optical integrator. FIG. 5(b) shows the illuminance distribution at the microlens 41b of the optical integrator. FIG. 5(c) shows the illuminance distribution at the microlens 41c of the optical integrator. FIG. 5(d) shows the illuminance distribution at the field stop 6. In addition, in FIG. 5(a) to FIG. 5(d), the vertical axis shows the illuminance, and the horizontal axis shows the position (diagonal) coordinate.

[0035] As shown in FIG. 4, FIG. 5(a), FIG. 5(b), FIG. 5(c) and FIG. 5(d), the illuminance distributions in the microlenses 41a, 41b and 41c are superimposed at the field stop 6, so that the illuminance at the periphery changes by ΔT [%] in the illuminance distribution at the field stop 6. Therefore, the illuminance unevenness at the field stop 6 is ΔT / (200-ΔT) [%]. Here, as described above, a case is considered in which the illuminance unevenness changes over time on the illuminated surface (illuminance distribution symmetrical around the optical axis AX of the illumination optical system 101) due to the aging of the illumination optical system 101. In this case, the adjustment unit 15 adjusts the amount of rotation of the optical filter 8 so as to cancel the aging of the illuminance unevenness, thereby reducing the illuminance unevenness and correcting the aging.

[0036] 6(a) to 6(d) and 7(a) and 7(d), a concept of changing the illuminance distribution on the illuminated surface by rotating the optical filter 8 by the adjustment unit 15 will be described. Here, a case will be described in which the optical filter 8 is rotated counterclockwise around the optical axis AX of the illumination optical system 101 by the adjustment unit 15, but the optical filter 8 may also be rotated clockwise.

[0037] FIG. 6(a) shows the illuminance distribution (change) at the microlens 41a of the optical integrator when the optical filter 8 is rotated. FIG. 6(b) shows the illuminance distribution at the microlens 41b of the optical integrator when the optical filter 8 is rotated. FIG. 6(c) shows the illuminance distribution at the microlens 41c of the optical integrator when the optical filter 8 is rotated. FIG. 6(d) shows the illuminance distribution at the field stop 6 when the optical filter 8 is rotated. In FIG. 6(a) to FIG. 6(d), the vertical axis shows the illuminance, and the horizontal axis shows the position (diagonal) coordinate.

[0038] As shown in FIG. 6(b), the microlens 41b located on the optical axis AX (center of rotation) of the illumination optical system 101 is less affected by the change in illuminance distribution due to the rotation of the optical filter 8. On the other hand, as shown in FIG. 6(a), the microlens 41a located on the positive Y coordinate shifts the light amount adjustment region 20a by the rotation of the optical filter 8, and is influenced by the light amount adjustment region 20 adjacent to the light amount adjustment region 20a. As shown in FIG. 6(c), the microlens 41a located on the negative Y coordinate shifts the light amount adjustment region 20c by the movement, and is influenced by the light amount adjustment region 20 adjacent to the light amount adjustment region 20c. The direction in which the illuminance distribution shifts in the microlens 41c is opposite to the direction in which the illuminance distribution shifts in the microlens 41a. Therefore, the illuminance distributions at each microlens 41a, 41b, and 41c are superimposed at the field stop 6, so that, as shown in Figure 6(d), in the illuminance distribution at the field stop 6, the illuminance (change) at the periphery becomes smaller than ΔT [%].

[0039] FIG. 7(a) shows the illuminance distribution (change) at the microlens 41a of the optical integrator when the optical filter 8 is further rotated. FIG. 7(b) shows the illuminance distribution at the microlens 41b of the optical integrator when the optical filter 8 is further rotated. FIG. 7(c) shows the illuminance distribution at the microlens 41c of the optical integrator when the optical filter 8 is further rotated. FIG. 7(d) shows the illuminance distribution at the field stop 6 when the optical filter 8 is further rotated. In addition, in FIG. 7(a) to FIG. 7(d), the vertical axis indicates the illuminance, and the horizontal axis indicates the position (diagonal) coordinate.

[0040] The illuminance distributions at the microlenses 41a, 41b, and 41c shown in Fig. 7(a), Fig. 7(b), and Fig. 7(c) are superimposed at the field stop 6, so that the illuminance distribution at the field stop 6 ideally has a constant illuminance, as shown in Fig. 7(d). In addition, by further rotating the optical filter 8, it is also possible to make the illuminance at the periphery higher than the illuminance at the center (origin) in the illuminance distribution at the field stop 6. In this way, by rotating the optical filter 8 with the adjustment unit 15 to adjust the amount of rotation of the optical filter 8, the illuminance distribution on the illuminated surface, particularly the illuminance at the periphery, can be arbitrarily changed.

[0041] Referring to FIG. 8, a process of correcting the change over time in the illuminance unevenness on the illuminated surface (symmetric illuminance distribution around the optical axis AX of the illumination optical system 101) by adjusting the amount of rotation of the optical filter 8 by the adjustment unit 15 under the control of the control unit 106 will be described.

[0042] In S1, the adjustment unit 15 adjusts (sets) the rotation amount of the optical filter 8 to a reference amount (for example, 0 degrees) in the illumination optical system 101. In S2, the measurement unit 105 measures the illuminance distribution on the illuminated surface.

[0043] In S3, the adjustment unit 15 determines the amount of rotation of the optical filter 8 to be adjusted based on the illuminance distribution measured in S2, which is required to cancel (minimize) the change over time in the illuminance unevenness on the illuminated surface. For example, an approximate quadratic coefficient of the illuminance distribution measured by the measurement unit 105 is calculated, and an optimal amount of rotation of the optical filter 8 required to cancel the change over time in the illuminance unevenness on the illuminated surface is obtained. The relationship between the amount of rotation of the optical filter 8 and the approximate quadratic coefficient of the illuminance distribution may be obtained by optical simulation or the like, and may be acquired in advance as a correction table. In addition, the actual measurement results obtained by measuring the change in the illuminance distribution on the illuminated surface by the measurement unit 105 while changing the amount of rotation of the optical filter 8 may be acquired in advance as a correction table. In this way, the adjustment unit 15 determines the amount of rotation of the optical filter 8 to be adjusted based on the illuminance distribution measured by the measurement unit 105, the amount of rotation of the optical filter 8, and the information indicating the relationship between the corresponding amount of change in the illuminance distribution on the illuminated surface.

[0044] In S4, the adjustment unit 15 rotates the optical filter 8, and the amount of rotation of the optical filter 8 is adjusted (set) to the amount of rotation determined in S3. In S6, the measurement unit 105 measures the illuminance distribution on the illuminated surface. In S7, it is determined whether the change over time in the illuminance unevenness on the illuminated surface has been canceled out based on the illuminance distribution measured in S6. Note that the change over time in the illuminance unevenness has been canceled out does not mean that the change over time in the illuminance unevenness has been completely canceled out, but means that the change over time in the illuminance unevenness is within an acceptable range. If the change over time in the illuminance unevenness has been canceled out, the process ends. On the other hand, if the change over time in the illuminance unevenness has not been canceled out, that is, if there is a correction residual, the process proceeds to S3 in order to cancel the change over time in the illuminance unevenness (correction residual).

[0045] In this manner, according to this embodiment, the adjustment unit 15 adjusts the amount of rotation of the optical filter 8, thereby making it possible to correct the change over time in the illuminance unevenness on the illuminated surface (symmetric illuminance distribution centered on the optical axis AX of the illumination optical system 101). Therefore, in the exposure apparatus 100, the original R (illuminated surface) can be uniformly illuminated regardless of the change over time of the illumination optical system 101, so that it is possible to suppress (reduce) poor transfer of the pattern of the original R to the substrate W. In addition, this embodiment uses the adjustment unit 15 that adjusts the amount of rotation of the optical filter 8, and does not require a driving range for driving the optical filter 8 in the optical axis direction as in the conventional technology, thereby making it possible to realize space saving for the illumination optical system 101.

[0046] It is also possible to optimize the illuminance unevenness for each illumination condition by determining the amount of rotation of the optical filter 8 required to counteract the change over time in the illuminance unevenness on the illuminated surface for each illumination condition in the illumination optical system 101.

[0047] 9, the transmittance distribution in the light amount adjustment region 20 of the optical filter 8 can also be realized by providing a shielding portion 21 for each light amount adjustment region 20, which defines an opening 22 centered on the center of the light amount adjustment region 20. The shielding portion 21 is made of chrome or the like, and defines the opening 22 having an opening diameter of diameter R. The shielding portion 21 has a transmittance lower than that of the opening 22. For example, if the transmittance of the opening 22 is 100[%], the transmittance of the shielding portion 21 is T, which is lower than 100[%]. C It should be noted that the shielding portion 21 and the opening 22 may be interchanged to realize a transmittance distribution in which the transmittance in the center is lower than the transmittance in the periphery.

[0048] FIG. 10 shows an example of the arrangement of the light amount adjustment regions 20 in which the shielding portions 21 are provided in the optical filter 8. As shown in FIG. 10, the light amount adjustment regions 20 are provided with the shielding portions 21 so that the openings 22 having different opening diameters R are defined from the center of the optical filter 8 toward the periphery. Also, the shielding portions 21 are provided in each light amount adjustment region 20 so that the openings 22 having the same opening diameter R are arranged rotationally symmetrically with respect to the center of the optical filter 8. In this way, the shielding portions 21 are provided so that the openings 22 having different opening diameters R are defined in the light amount adjustment regions 20 of the optical filter 8. As a result, the light passing through each of the light amount adjustment regions 20 (openings 22) of the optical filter 8 is superimposed by the optical integrator 4, so that the illuminance distribution on the illuminated surface has a pseudo-secondary shape. Therefore, it is possible to cancel the change over time in the illuminance unevenness on the illuminated surface by rotating the optical filter 8 shown in FIG. 10 around the optical axis AX of the illumination optical system 101.

[0049] The manufacturing method of an article according to an embodiment of the present invention is suitable for manufacturing articles such as semiconductor elements, flat panel displays, liquid crystal display elements, and MEMS. The manufacturing method includes a step of exposing a substrate coated with a photosensitive agent using the above-mentioned exposure apparatus 100, and a step of developing the exposed photosensitive agent. In addition, an etching step, an ion implantation step, and the like are performed on the substrate using the developed pattern of the photosensitive agent as a mask, and a circuit pattern is formed on the substrate. These steps of exposure, development, etching, and the like are repeated to form a circuit pattern consisting of multiple layers on the substrate. In a post-process, dicing (processing) is performed on the substrate on which the circuit pattern is formed, and chip mounting, bonding, and inspection steps are performed. In addition, the manufacturing method may include other well-known steps (oxidation, film formation, deposition, doping, planarization, resist peeling, and the like). The manufacturing method of an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to the conventional method.

[0050] The disclosure of this specification includes the following illumination optical system, exposure apparatus, and method for manufacturing an article.

[0051] (Item 1) An illumination optical system that illuminates an illumination target surface with light from a light source, an optical integrator in which a plurality of optical elements are arranged; a filter in which a plurality of light amount adjustment regions corresponding to the plurality of optical elements are arranged; an adjustment unit that adjusts a rotation amount of the filter around an optical axis of the illumination optical system relative to the optical integrator; having Each of the plurality of light amount adjustment regions has a transmittance distribution in which the transmittance changes from the center to the periphery of each light amount adjustment region, the adjustment unit adjusts the amount of rotation of the filter so as to cancel out changes over time in illuminance unevenness on the illuminated surface. 1. An illumination optical system comprising:

[0052] (Item 2) 2. The illumination optical system according to item 1, wherein the transmittance distribution is a distribution that is rotationally symmetric with respect to the center of each light amount adjustment region.

[0053] (Item 3) 3. The illumination optical system according to item 1 or 2, wherein the transmittance distribution is a distribution that is convex or concave from the center of each light amount adjustment region toward the periphery.

[0054] (Item 4) 4. The illumination optical system according to any one of items 1 to 3, wherein the filter is disposed between the light source and the optical integrator so as to be optically conjugate with the illuminated surface.

[0055] (Item 5) 5. The illumination optical system according to any one of items 1 to 4, wherein the plurality of light amount adjustment regions are arranged rotationally symmetrically with respect to the center of the filter.

[0056] (Item 6) An anti-reflection film is provided on each of the plurality of light amount adjustment regions, the anti-reflection film has a thickness that varies partially within the surface of each light amount adjustment region; 6. An illumination optical system according to any one of items 1 to 5,

[0057] (Item 7) 7. The illumination optical system according to item 6, wherein the antireflection film has a film thickness distribution that is rotationally symmetric with respect to the center of each light amount adjustment region.

[0058] (Item 8) Each of the plurality of light amount adjustment regions is provided with a shielding portion that defines an opening centered on the center of the corresponding light amount adjustment region, The shielding portion has a transmittance lower than a transmittance of the opening portion. 6. An illumination optical system according to any one of items 1 to 5,

[0059] (Item 9) 9. The illumination optical system described in item 8, characterized in that a plurality of openings having different opening diameters from each other are defined in the plurality of light adjustment regions from the center of the filter toward the periphery, and a plurality of the shielding portions are provided so that the openings having the same opening diameter are arranged rotationally symmetrically about the center of the filter.

[0060] (Item 10) 10. The illumination optical system according to any one of items 1 to 9, further comprising a control unit that controls an amount of rotation of the filter to be adjusted by the adjustment unit.

[0061] (Item 11) A measurement unit that measures an illuminance distribution on the illuminated surface, the control unit controls the amount of rotation of the filter to be adjusted by the adjustment unit based on the illuminance distribution measured by the measurement unit. 11. The illumination optical system according to item 10,

[0062] (Item 12) The control unit determines an amount of rotation of the filter that should be adjusted by the adjustment unit to counteract changes over time in illuminance unevenness on the illuminated surface, based on information indicating a relationship between the illuminance distribution measured by the measurement unit, and the amount of rotation of the filter and the amount of change in illuminance distribution on the illuminated surface corresponding to the amount of rotation.

[0063] (Item 13) An exposure apparatus that exposes a substrate through an original, comprising: An illumination optical system according to any one of items 1 to 12, which illuminates the original placed on an illumination surface; a projection optical system that projects a pattern of the original onto the substrate; An exposure apparatus comprising:

[0064] (Item 14) Exposing a substrate using the exposure apparatus according to Item 13; developing the exposed substrate; producing an article from the developed substrate; A method for producing an article, comprising the steps of:

[0065] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0066] 100: exposure device 4: optical integrator 8: optical filter 15: adjustment unit 20: light amount adjustment area 101: illumination optical system 106: control unit

Claims

1. An illumination optical system that illuminates an illumination target surface with light from a light source, an optical integrator in which a plurality of optical elements are arranged; a filter in which a plurality of light amount adjustment regions corresponding to the plurality of optical elements are arranged; an adjustment unit that adjusts a rotation amount of the filter around an optical axis of the illumination optical system relative to the optical integrator; having Each of the plurality of light amount adjustment regions has a transmittance distribution in which the transmittance changes from the center to the periphery of each light amount adjustment region, the adjustment unit adjusts the amount of rotation of the filter so as to cancel out changes over time in illuminance unevenness on the illuminated surface.

1. An illumination optical system comprising:

2. 2. The illumination optical system according to claim 1, wherein the transmittance distribution is rotationally symmetric with respect to the center of each light amount adjustment region.

3. 2. The illumination optical system according to claim 1, wherein the transmittance distribution is a distribution that is convex or concave from the center of each light amount adjustment region toward its periphery.

4. 2. The illumination optical system according to claim 1, wherein the filter is disposed between the light source and the optical integrator so as to be optically conjugate with the illuminated surface.

5. 2. The illumination optical system according to claim 1, wherein the plurality of light amount adjustment regions are arranged rotationally symmetrically with respect to a center of the filter.

6. An anti-reflection film is provided in each of the plurality of light amount adjustment regions, the anti-reflection film has a thickness that varies partially within the surface of each light amount adjustment region; 2. The illumination optical system according to claim 1.

7. 7. The illumination optical system according to claim 6, wherein the antireflection film has a film thickness distribution that is rotationally symmetric with respect to the center of each light amount adjustment region.

8. Each of the plurality of light amount adjustment regions is provided with a shielding portion that defines an opening centered on the center of the corresponding light amount adjustment region, The shielding portion has a transmittance lower than a transmittance of the opening portion.

2. The illumination optical system according to claim 1.

9. 9. The illumination optical system according to claim 8, wherein a plurality of openings having different aperture diameters are defined in the plurality of light adjustment regions from a center of the filter toward a periphery thereof, and a plurality of the shielding portions are provided so that the openings having the same aperture diameter are arranged rotationally symmetrically about the center of the filter.

10. 2. The illumination optical system according to claim 1, further comprising a control unit that controls an amount of rotation of the filter to be adjusted by the adjustment unit.

11. A measurement unit that measures an illuminance distribution on the illuminated surface, The control unit controls the amount of rotation of the filter to be adjusted by the adjustment unit based on the illuminance distribution measured by the measurement unit.

11. The illumination optical system according to claim 10.

12. The illumination optical system according to claim 11, characterized in that the control unit determines the amount of rotation of the filter that should be adjusted by the adjustment unit in order to counteract changes over time in illuminance unevenness on the illuminated surface, based on information indicating a relationship between the illuminance distribution measured by the measurement unit, and the amount of rotation of the filter and the amount of change in illuminance distribution on the illuminated surface corresponding to the amount of rotation.

13. An exposure apparatus that exposes a substrate through an original, comprising: an illumination optical system according to claim 1 , which illuminates the original placed on an illumination surface; a projection optical system that projects a pattern of the original onto the substrate; An exposure apparatus comprising:

14. exposing a substrate using the exposure apparatus according to claim 13; developing the exposed substrate; producing an article from the developed substrate; A method for producing an article, comprising the steps of:

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