JP7625376B2 - METHOD FOR MANUFACTURING TRANSMISSION OPTICAL ELEMENT, EXPOSURE APPARATUS, METHOD FOR MANUFACTURING ARTICLE, AND TRANSMISSION OPTICAL ELEMENT - Google Patents

Description

The present invention relates to a manufacturing method for a transmissive optical element, an exposure apparatus, a manufacturing method for an article, and a transmissive optical element.

In the lithography process for manufacturing articles such as semiconductor devices, an exposure apparatus is used that has an illumination optical system that illuminates an original and a projection optical system that projects the pattern of the original illuminated by the illumination optical system onto a substrate. The pattern of the original is projected onto the substrate, and the pattern is transferred to a resist (photosensitive agent) that is disposed (coated) on the surface of the substrate. In an exposure apparatus, if the illumination of the original is non-uniform, the pattern may not be transferred well to the resist on the substrate. Therefore, in order to illuminate the original with uniform illuminance, a rod-type optical integrator or an optical integrator that includes multiple wavefront division elements arranged two-dimensionally is used in the illumination optical system.

On the other hand, in illumination optical systems, non-uniformity in the illuminance distribution on the illuminated surface may be observed due to contamination or decentering of the optical system, unevenness in the anti-reflection coating, etc. Therefore, a technology has been disclosed in which a filter with a dot pattern (light shielding object) on a quartz substrate is placed in a position that is optically conjugate with the illuminated surface, and the dot density (transmittance distribution) is changed to uniform the illuminance distribution on the illuminated surface (see Patent Document 1).

JP 2006-210554 A

However, with the technology disclosed in Patent Document 1, it is difficult to uniformize the illuminance distribution on the illuminated surface with sufficient precision. For example, when it is necessary to slightly change the transmittance using a filter, the number of dots is reduced, and the error in the transmittance due to the error in the dot size becomes large, making it impossible to correct the illuminance distribution on the illuminated surface with high precision.

The present invention has been made in consideration of the problems with the conventional technology, and has as an example objective the provision of technology relating to a transmissive optical element that is advantageous in achieving a uniform illuminance distribution on an illuminated surface.

In order to achieve the above-mentioned object, a manufacturing method as one aspect of the present invention is a method for manufacturing a light-transmitting optical element to be incorporated in an illumination optical system that illuminates an illuminated surface , the method comprising the steps of: forming an optical thin film on a surface of the optical element by superimposing a plurality of thin films having different refractive indices ; acquiring an illuminance distribution formed on the illuminated surface; designing a light transmittance distribution of the optical thin film based on the acquired illuminance distribution; determining a portion of the surface of the optical element where the optical thin film should be removed and an amount of the optical thin film to be removed in the portion according to the light transmittance distribution; and removing the optical thin film formed on the surface of the optical element by the amount of removal in a thickness direction of the optical thin film such that a portion of the optical thin film remains in the portion to be removed .

Further objects and other aspects of the present invention will become apparent from the embodiments described below with reference to the accompanying drawings.

The present invention can provide, for example, technology relating to a transmissive optical element that is advantageous for achieving a uniform illuminance distribution on an illuminated surface.

1 is a schematic diagram showing a configuration of an exposure apparatus according to one aspect of the present invention. FIG. 1 is a schematic diagram showing a configuration of a light-transmitting optical element. 1 is a flowchart illustrating a method for manufacturing an optical element according to one aspect of the present invention. 4 is a flowchart for illustrating in detail step S02 shown in FIG. 3. FIG. 4 is a diagram for explaining step S02 shown in FIG. 3 in detail. FIG. 4 is a diagram for explaining step S02 shown in FIG. 3 in detail. 5 is a diagram for explaining a specific technique for the removal process in S24 shown in FIG. 4. 5 is a diagram for explaining a specific technique for the removal process in S24 shown in FIG. 4. 5 is a diagram for explaining a specific technique for the removal process in S24 shown in FIG. 4. 5 is a diagram for explaining a specific technique for the removal process in S24 shown in FIG. 4.

The following embodiments are 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 multiple features, not all of these multiple features are necessarily essential to the invention, and multiple 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 duplicate explanations are omitted.

Figure 1 is a schematic diagram showing the configuration of an exposure apparatus 100 according to one aspect of the present invention. The exposure apparatus 100 is a lithography apparatus used, for example, in a manufacturing process (lithography process) for semiconductor devices and the like, for forming a pattern on a substrate. The exposure apparatus 100 exposes a substrate W via an original R, and in this embodiment, is a step-and-scan exposure apparatus (scanner) that exposes the substrate W (scanning exposure) while moving the original R and the substrate W in the scanning direction, thereby transferring the pattern of the original R onto the substrate. However, the exposure apparatus 100 can also employ a step-and-repeat method or other exposure methods.

As shown in FIG. 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, and a measurement unit 105. In this embodiment, a coordinate system is defined in which the axis along the normal direction of the substrate W is the Z axis, and the axes along directions perpendicular to each other in a plane parallel to the substrate W are the X axis and the Y axis.

The illumination optical system 101 uses light (light beam) from the light source 1 to illuminate the original R placed on the illuminated surface (object surface of the projection optical system 103). 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 light with an extreme ultraviolet wavelength (EUV light) of about 11 nm to 14 nm.

The original R has a pattern (e.g., a circuit pattern) to be transferred to the substrate W formed thereon. 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 drive unit 102 includes, for example, a movable original stage that holds the original R, and an original drive mechanism that drives the original stage about the X-axis and Z-axis.

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 the surface (position) on which the original R is placed, and the rear focal point of which is located on the surface on which the substrate W is placed. In other words, the projection optical system 103 makes the placement position of the original R and the placement position of the substrate W conjugate with each other.

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 drive unit 104 includes a movable substrate stage that holds the substrate W, and a substrate drive mechanism that drives the substrate stage about the X-axis, Y-axis, and Z-axis (and their respective rotational directions ωx, ωy, and ωz).

The measurement unit 105 includes, for example, a light quantity sensor, and measures the illuminance distribution formed on the illuminated surface. In this embodiment, the measurement unit 105 is disposed on the object surface of the projection optical system 103, specifically, on the original stage that constitutes the original driving unit 102.

The illumination optical system 101 will be described in detail below. The illumination optical system 101 includes a first relay lens 3, a folding mirror M1, an optical integrator 4, a second relay lens 5, and a folding mirror M2. The first relay lens 3 and the folding mirror M1 constitute the first illumination optical system 10, and the second relay lens 5 and the folding mirror M2 constitute the second illumination optical system 12. Light from the first illumination optical system 10 enters the second illumination optical system 12 via the optical integrator 4.

The elliptical mirror 2 has a first focus and a second focus, and focuses light from the light source 1 arranged at the first focus at the second focus. The first relay lens 3 includes an imaging optical system, the front focus of which is arranged at the second focus of the elliptical mirror 2, and the rear focus of which is arranged at the incident surface of the optical integrator 4. In other words, the first relay lens 3 makes the second focus of the elliptical mirror 2 and the incident surface of the optical integrator 4 in a conjugate relationship. Thus, in this embodiment, the illumination optical system 101 includes the first illumination optical system 10 that makes the second focus of the elliptical mirror 2 and the incident surface of the optical integrator 4 in a conjugate relationship, but may include a first illumination optical system that does not have such a relationship. A wavelength filter (not shown) that blocks light in a specific wavelength range is arranged near the pupil plane of the first relay lens 3, and the exposure wavelength (the wavelength of light that exposes the substrate W) is determined by the wavelength filter.

The optical integrator 4 is an internal reflection type optical integrator including an incident surface, a reflecting surface, and an exit surface ES. The optical integrator 4 forms a uniform light intensity distribution (illuminance distribution) on the exit surface ES by reflecting the light incident on the incident surface multiple times by the reflecting surface. In this embodiment, the optical integrator 4 has a rectangular shape in a cross section (XY plane) perpendicular to the optical axis AX, but may have other shapes (e.g., polygonal). Furthermore, the optical integrator 4 is not limited to an internal reflection type optical integrator, and may be a microlens array type optical integrator such as a fly-eye lens.

The second illumination optical system 12 illuminates the original R using light from the exit surface ES of the optical integrator 4. The second relay lens 5 includes an imaging optical system, the front focal point of which is located at the exit surface ES of the optical integrator 4, and the rear focal point of which is located on the surface on which the original R is placed. In other words, the second relay lens 5 makes the exit surface ES of the optical integrator 4 and the placement surface of the original R conjugate with each other. The second relay lens 5 forms a light intensity distribution (illuminance distribution) of the exit surface ES of the optical integrator 4 on the placement surface of the original R.

In the exposure apparatus 100 of this embodiment, the second illumination optical system 12 incorporates a light-transmitting optical element 6 that functions as a correction filter to correct the illuminance distribution on the illuminated surface. The optical element 6 is disposed on the illuminated surface of the illumination optical system 101 (e.g., the surface on which the original R is placed), on a conjugate surface that is conjugate with the illuminated surface, or near the illuminated surface or the conjugate surface. In this embodiment, the optical element 6 is disposed near the surface on which the original R is placed, specifically, on the surface of the illumination optical system 101 closest to the projection optical system 103 so that an optical thin film formed on the surface of the optical element 6, which will be described later, faces the original R.

Figure 2 is a schematic diagram showing the configuration of a light-transmitting optical element 6. As shown in Figure 2, the optical element 6 has an optical thin film C formed on at least one surface (surface of the optical element 6) of the substrate 7 (base material) and functioning (acting) as an anti-reflection film. In this embodiment, for any part (portion) of the optical thin film C having a thickness (maximum thickness) D, the optical thin film C is partially removed in the thickness direction (Z-axis direction) of the optical thin film C by an amount of removal δ, thereby forming a film thickness distribution in the optical thin film surface. In this way, the optical thin film C exists across the surface of the optical element 6 (substrate 7) and has a film thickness distribution in this surface. In other words, the optical thin film C includes a part where the optical thin film C is partially removed in the thickness direction in the surface of the optical element 6, and at least a part of the optical thin film C remains in this part.

The anti-reflection film as the optical thin film C is constructed by stacking multiple thin films made of materials with different refractive indices on the substrate 7, and uses optical interference to reduce the reflectance and obtain a high overall transmittance. The number, material, and thickness of each thin film constituting the anti-reflection film are usually adjusted to obtain a predetermined transmittance or reflectance, and the optical interference conditions are optimized. Therefore, the transmittance or reflectance of the optical thin film C can be changed according to the amount δ removed when partially removing the optical thin film C in the thickness direction. The type (film type) of the optical thin film C is not limited to a dielectric multilayer film, and may be a single layer film.

On the other hand, if the optical thin film C formed on the substrate 7 is completely removed in the thickness direction, the portion of the optical thin film C from which it has been completely removed in the thickness direction will no longer function as an anti-reflection film. However, for the purpose of correcting the illuminance distribution on the illuminated surface, i.e., for the purpose of making the illuminance distribution uniform, the amount δ of the optical thin film C removed may be sufficient to adjust the film thickness (film thickness distribution) of the outermost thin film among the multiple thin films that make up the anti-reflection film. Therefore, in this embodiment, the effect of the partial removal of the optical thin film C in the thickness direction on its function as an anti-reflection film is extremely small and can be ignored.

The manufacturing method for manufacturing the optical element 6 will be described below with reference to FIG. 3. In S01 (first step), an optical thin film C that functions as an anti-reflection film is formed on the surface of the substrate 7. As described above, the optical thin film C formed in S01 has the number, material, thickness, etc. of the thin films that make up the optical thin film C adjusted to optimize the optical interference conditions. In this embodiment, an optical thin film C with a uniform thickness D is formed on the surface of the substrate 7.

In S02 (second step), the optical thin film C formed in S01 is removed in the thickness direction. At this time, the optical thin film C is removed in the thickness direction so that at least a part of the optical thin film C remains even in the area where the optical thin film C is removed. Therefore, even after S02, at least a part of the optical thin film C formed on the surface of the substrate 7 remains in the thickness direction of the optical thin film C across the surface of the substrate 7. In this embodiment, the optical thin film C is partially removed in the thickness direction of the optical thin film C by a removal amount δ for any location of the optical thin film C having a thickness D. As a result, as shown in FIG. 2, a transmission type optical element 6 can be manufactured in which an optical thin film C is formed that exists across the surface of the substrate 7 and has a thickness distribution across the surface.

Now, with reference to Figure 4, the process of removing the optical thin film C in the thickness direction (step S02) will be described in detail.

In S21 (third step), the illuminance distribution formed on the illuminated surface by the light from the illumination optical system 101 with the transmissive optical element 6 removed is acquired. Specifically, the measurement unit 105 provided on the original stage is placed on the surface on which the original R is placed, and the light from the illumination optical system 101 with the transmissive optical element 6 removed is measured by the measurement unit 105 (light quantity sensor) to acquire the illuminance distribution on the illuminated surface. Figure 5(a) is a diagram showing an example of the illuminance distribution on the illuminated surface acquired in S21. In the illuminance distribution shown in Figure 5(a), the illuminance is locally low at coordinate a on the illuminated surface.

In S22, a transmittance distribution in the optical thin film C functioning as an anti-reflection film is designed so as to cancel the illuminance distribution on the illuminated surface acquired in S21. Fig. 5(b) is a diagram showing an example of the transmittance distribution in the optical thin film C designed in S22. The transmittance distribution shown in Fig. 5(b) is a transmittance distribution designed for the illuminance distribution shown in Fig. 5(a), and has a maximum transmittance _Tmax at coordinate A in the optical thin film surface corresponding to coordinate a in the illuminated region.

In S23 (fourth step), the film thickness distribution of the optical thin film C is determined based on the illuminance distribution on the illuminated surface acquired in S21 and the transmittance distribution of the optical thin film C designed in S22. The determination of the film thickness distribution of the optical thin film C means determining the portion (coordinates in the optical thin film plane) where the optical thin film C should be removed on the surface of the optical element 6 (substrate 7) and the removal amount δ of the optical thin film C in the portion. Specifically, as shown in FIG. 5(c), the illuminance distribution shown in FIG. 5(a) is multiplied with the transmittance distribution shown in FIG. 5(b) to determine the film thickness distribution of the optical thin film C so that the illuminance distribution on the illuminated surface becomes uniform (i.e., so as to realize the transmittance distribution shown in FIG. 5(b)). Referring to FIG. 5(c), the removal amount δ at the coordinate A in the optical thin film plane having the maximum transmittance T _max is set to zero as the film thickness distribution of the optical thin film C, and the removal amount δ is determined according to the transmittance difference (T _max -T) between the maximum transmittance T _max and the transmittance T at each coordinate (position). 6 shows the relationship between the transmittance difference (T _max -T) and the removal amount 6. By acquiring such a relationship in advance, it becomes possible to determine the removal amount 6 according to the transmittance difference (T _max -T) for each coordinate (position) in the optical thin film plane.

In S24, the optical thin film C formed on the substrate 7 in S01 is subjected to a removal process to partially remove the optical thin film C in the thickness direction according to the film thickness distribution determined in S23 (the amount of removal δ at each coordinate in the optical thin film plane). As a result, the optical thin film C exists across the surface of the substrate 7, and has a film thickness distribution within the surface of the substrate 7 that corresponds to the illuminance distribution that should be formed by the light transmitted through the optical element 6. The specific method of the removal process performed in S24 will be described later.

In S25, the optical element 6 that has been subjected to the removal process in S24 is incorporated into the illumination optical system 101. In this embodiment, as described above, the optical element 6 is incorporated into the surface of the illumination optical system 101 closest to the projection optical system 103, so that the optical thin film C faces the original R.

In S26, the illuminance distribution formed on the illuminated surface by the light from the illumination optical system 101 with the transmissive optical element 6 incorporated is acquired. Specifically, the measurement unit 105 provided on the original stage is placed on the surface on which the original R is placed, and the light from the illumination optical system 101 with the transmissive optical element 6 incorporated is measured by the measurement unit 105 (light quantity sensor) to acquire the illuminance distribution on the illuminated surface. Figure 5(d) is a diagram showing an example of the illuminance distribution on the illuminated surface acquired in S26. The illuminance distribution shown in Figure 5(d) has a uniform illuminance within the illuminated surface.

In this way, according to this embodiment, it is possible to manufacture (provide) a transmissive optical element 6 that realizes a uniform illuminance distribution on the illuminated surface. An exposure apparatus 100 having an illumination optical system 101 incorporating such a transmissive optical element 6 is able to uniformly illuminate the original R, and can satisfactorily transfer the pattern of the original R to the resist on the substrate.

With reference to FIG. 7, an example of a specific technique for the removal process (S24) of partially removing the optical thin film C in the thickness direction will be described. The removal process may use a processing technique known as IBF (Ion Beam Figuring), which irradiates an ion beam onto the portion of the optical thin film C to be removed, thereby removing the optical thin film C in the thickness direction in the portion.

Figure 7 is a schematic diagram showing the configuration of an ion beam processing apparatus 200 that realizes IBF. The ion beam processing apparatus 200 has a chamber 21 for maintaining a vacuum state, an ion beam generating unit 22, a driving stage 24, and a current density measuring unit 25. The ion beam generating unit 22, the driving stage 24, and the current density measuring unit 25 are provided inside the chamber 21.

The ion beam 23 from the ion beam generator 22 is irradiated onto a transmissive optical element 6, which is the workpiece held (mounted) on a driving stage 24, specifically, onto an optical thin film C formed on a substrate 7. The driving stage 24 is driven in a scanning manner to irradiate any portion (position) of the optical thin film C with the ion beam 23, thereby performing a removal process that partially removes the optical thin film C in the thickness direction.

By irradiating the ion beam 23 from the ion beam generating unit 22 to the current density measuring unit 25 provided on the driving stage 24, it is possible to measure the beam profile of the ion beam 23. By optimizing the beam profile of the ion beam 23 measured by the current density measuring unit 25 for processing conditions such as the removal amount δ (processing amount) of the optical thin film C and the processing pitch, it is possible to realize highly accurate removal processing.

By using such an ion beam processing device 200 for the removal processing (S24), it is possible to manufacture (provide) a transmissive optical element 6 that can correct the non-uniformity of the illuminance distribution on the illuminated surface with high precision, i.e., achieve uniformity of the illuminance distribution on the illuminated surface.

With reference to FIG. 8, another example of a specific technique for the removal process (S24) for partially removing the optical thin film C in the thickness direction will be described. For the removal process, a processing technique known as MRF (Magneto-Rheological Finishing) may be used, in which the portion where the optical thin film C is to be removed is polished with a magnetic fluid containing abrasive grains, thereby removing the optical thin film C in the thickness direction in the portion. MRF is a high-precision polishing technique that uses magnetic force.

Specifically, as shown in FIG. 8, a magnetic fluid 31 containing abrasive grains is poured between an optical thin film C formed on a substrate 7 and a stage 32. When a magnetic force 34 is applied to the magnetic fluid 31 from an electromagnet 33, the magnetic force 34 causes the magnetic abrasive grains contained in the magnetic fluid 31 to come into contact with the surface of the optical thin film C. At this time, the stage 32 is driven to cause the magnetic fluid 31 to flow over the surface of the optical thin film C, which is then polished by the magnetic fluid 31. By controlling the magnetic force 34 from the electromagnet 33, a highly accurate removal process can be achieved.

By using such high-precision polishing technology in the removal process (S24), it is possible to manufacture (provide) a transmissive optical element 6 that corrects the non-uniformity of the illuminance distribution on the illuminated surface with high precision, i.e., achieves uniformity of the illuminance distribution on the illuminated surface.

With reference to Figures 9(a) to 9(d), yet another example of a specific technique for the removal process (S24) of partially removing the optical thin film C in the thickness direction will be described. The removal process may be a processing technique for removing the optical thin film C in the thickness direction in the portion where the optical thin film C should be removed by etching the portion, for example, an etching technique using a resist.

Specifically, first, as shown in FIG. 9(a), resist 41 is applied onto the optical thin film C formed on the substrate 7. Next, as shown in FIG. 9(b), a portion 42 from which the optical thin film C is to be removed is exposed to light using an exposure device or the like and developed, thereby removing the resist 41 from the portion 42. Next, as shown in FIG. 9(c), etching is performed on the portion 42 to remove (scrape) the optical thin film C from the portion 42. Then, as shown in FIG. 9(d), the resist 41 applied onto the optical thin film C is peeled off. By going through the steps shown in FIG. 9(a) to FIG. 9(d), highly accurate removal processing can be achieved for any portion of the optical thin film C.

By using such an etching technique for the removal process (S24), it is possible to manufacture (provide) a transmissive optical element 6 that can correct the non-uniformity of the illuminance distribution on the illuminated surface with high precision, i.e., achieve a uniform illuminance distribution on the illuminated surface.

With reference to Figures 10(a) to 10(c), yet another example of a specific technique for the removal process (S24) of partially removing the optical thin film C in the thickness direction will be described. The removal process may use a processing technique in which a remover is applied to the portion of the optical thin film C from which the optical thin film C should be removed, thereby removing the optical thin film C in the thickness direction in that portion. For example, HF (hydrofluoric acid) is used as the remover.

Specifically, first, as shown in FIG. 10(a), a mask 51 including an opening 52 is placed on the optical thin film C formed on the substrate 7. Next, as shown in FIG. 10(b), a remover 53 is poured into the opening 52 of the mask 51 to remove (peel off) the optical thin film C in the portion exposed in the opening 52. Then, as shown in FIG. 10(c), the mask 51 placed on the optical thin film C is removed. By going through the steps shown in FIG. 10(a) to FIG. 10(c), highly accurate removal processing can be achieved for any portion of the optical thin film C.

By using such a technique using a release agent in the removal process (S24), it is possible to manufacture (provide) a transmissive optical element 6 that corrects the non-uniformity of the illuminance distribution on the illuminated surface with high precision, i.e., achieves uniformity of the illuminance distribution on the illuminated surface.

The manufacturing method of the article in the 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 photosensitive agent pattern 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 stripping, etc.). The manufacturing method of the article in 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.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible without departing from the spirit and scope of the invention. Therefore, the following claims are appended to disclose the scope of the invention.

100: Exposure device 101: Illumination optical system 103: Projection optical system 6: Transmissive optical element 7: Substrate C: Optical thin film

Claims (11)

A method for manufacturing a light-transmitting optical element to be incorporated in an illumination optical system that illuminates an illuminated surface, comprising the steps of:
forming an optical thin film on a surface of the optical element by superposing a plurality of thin films having refractive indices different from each other;
acquiring an illuminance distribution formed on the illuminated surface;
designing a light transmittance distribution of the optical thin film based on the acquired illuminance distribution;
determining a portion of the surface of the optical element where the optical thin film should be removed and an amount of the optical thin film to be removed in that portion according to the light transmittance distribution;
removing the optical thin film formed on the surface of the optical element in a thickness direction of the optical thin film by the removal amount so that a portion of the optical thin film remains in the portion to be removed. The manufacturing method according to claim 1, characterized in that the optical thin film includes an anti-reflection film. The manufacturing method according to claim 1 or 2, characterized in that in the removing step, an ion beam is irradiated onto a portion of the surface where the optical thin film is to be removed, thereby removing the optical thin film in the thickness direction in that portion. The manufacturing method according to claim 1 or 2, characterized in that in the removing step, the portion of the surface from which the optical thin film is to be removed is polished with a magnetic fluid containing abrasive grains, thereby removing the optical thin film in the portion in the thickness direction. The manufacturing method according to claim 1 or 2, characterized in that in the removing step, the optical thin film is removed in the thickness direction in the portion of the surface where the optical thin film is to be removed by etching the portion. The manufacturing method according to claim 1 or 2, characterized in that in the removing step, a remover is applied to the portion of the surface from which the optical thin film is to be removed, thereby removing the optical thin film in the thickness direction in that portion. The manufacturing method according to claim 1, characterized in that in the determining step, the portion and the amount of removal are determined so that an illuminance distribution that cancels out the illuminance distribution is formed on the illuminated surface by the light transmitted through the optical element. An exposure apparatus that exposes a substrate through an original, comprising:
an illumination optical system that illuminates the original disposed on an illumination surface ;
a projection optical system that projects the pattern of the original illuminated by the illumination optical system onto the substrate,
the illumination optical system includes a transmission type optical element having an anti-reflection film formed on a surface thereof, the anti-reflection film being formed by overlapping a plurality of thin films having refractive indices different from one another;
the anti-reflection film is formed on at least one entire surface of the optical element, and has a film thickness distribution determined so as to make the illuminance distribution on the illuminated surface uniform.
An exposure apparatus comprising: The exposure apparatus according to claim 8, characterized in that the optical element is disposed on the illuminated surface of the illumination optical system or on a conjugate surface of the illuminated surface. 9. An exposure apparatus according to claim 8, wherein the optical element is disposed on the side of the illumination optical system that is closest to the projection optical system, so that the anti-reflection film faces the original. exposing a substrate using an exposure apparatus according to any one of claims 9 to 10;
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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