JP2018084637A - Optical element, exposure equipment, and manufacturing method of article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element advantageous for correcting such a complex deformation as having a plurality of inflection points.SOLUTION: An optical element 2 includes: a mirror 21 having an optical surface 21a equipped with a reflection coating and a non-optical surface 21b on an opposite side with regard to the optical surface 21a; and a plurality of correction films 23 disposed on the non-optical surface 21b side and configured to correct a form of the mirror 21. The plurality of correction films 23 are disposed separated into a plurality of areas different from one another at the non-optical surface 21b side.SELECTED DRAWING: Figure 1

Description

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

  In a projection exposure apparatus used for manufacturing semiconductors, in order to cope with aberration deterioration due to temperature changes during exposure, there is a technique for correcting the aberration by changing the shape of the reflecting surface of the mirror used in the optical system. is there. An optical element having a variable shape is formed thin (for example, about 5 mm) so as to be easily deformed, but there is a concern that the element may be deformed due to various factors due to the thinness.

  In general, as a method for correcting the deformation of the mirror, a thin film is formed on the non-optical surface opposite to the reflecting surface (that is, the optical surface) of the mirror, and the internal stress on the optical surface side is determined by the internal stress of the non-optical surface. There is a method of correcting the deformation of the mirror by canceling. For example, in the method described in Patent Literature 1, a thin film having a non-optical surface is formed to have an arbitrary thickness by using a control plate for controlling the film thickness distribution, and the deformation of the optical element is corrected.

Japanese Patent Laid-Open No. 2005-19485

  However, in the method using the film thickness distribution control plate of Patent Document 1, correction is possible if the deformation of the optical element is a low-order deformation such as a spherical deformation, but it is complicated such as having a plurality of inflection points. It is disadvantageous when correcting the deformation.

  An object of the present invention is to provide an optical element that is advantageous for correcting a complex deformation having, for example, a plurality of inflection points.

  In order to solve the above problems, the present invention is provided on an optical surface provided with a reflective film, an optical element body having a non-optical surface opposite to the optical surface, and the non-optical surface side. A plurality of correction films for correcting the shape of the optical element body, wherein the plurality of correction films are provided in a plurality of different regions on the non-optical surface side. It is characterized by.

  According to the present invention, it is possible to provide an optical element that is advantageous in that, for example, a complicated deformation having a plurality of inflection points is corrected.

It is a schematic sectional drawing which shows the structure of the optical element which concerns on 1st Embodiment. It is a schematic sectional drawing which shows the structure of a variable shape optical element unit. It is a schematic diagram which shows the deformation | transformation state by the thin film in disc glass. It is a schematic diagram showing deformation by a thin film in a deformable optical element having a curved surface and distribution in thickness. It is sectional drawing which shows arrangement | positioning of the masking for the area | region production | generation of a correction | amendment film | membrane. It is a schematic sectional drawing which shows the deformation | transformation state of the mirror by the internal stress of a film | membrane when the thickness of the correction | amendment film | membrane of a non-optical surface is made the whole surface uniform. It is a figure for calculating | requiring arrangement | positioning of masking from the deformation | transformation of the mirror by a film | membrane stress. It is a figure for demonstrating arrangement | positioning of a masking. It is a flowchart explaining the manufacturing method of an optical element. It is a schematic sectional drawing which shows the structure of the optical element which concerns on 2nd Embodiment. It is a schematic sectional drawing which shows the structure of the optical element which concerns on 3rd Embodiment. It is a schematic sectional drawing which shows the structure of the optical element which concerns on the modification of 3rd Embodiment. It is the schematic which shows the structure of the exposure apparatus which concerns on 4th Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the following embodiments, a mirror will be described as an example of an optical element, but the effect is the same even if the mirror is replaced with another optical element (prism, lens) or the like.

[First Embodiment]
FIG. 1 is a schematic cross-sectional view showing the configuration of the optical element 2 according to the first embodiment of the present invention. The optical element 2 is provided on a mirror (that is, an optical element body) 21 having an optical surface 21a that reflects light and a non-optical surface 21b opposite to the optical surface 21a, and the non-optical surface 21b. And a correction film 23 as a first film for correcting the deformation of the shape 21. As will be described later, the correction film 23 includes a plurality of film regions 23-n. Further, the optical element 2 includes a reflection film 22 as a second film for improving the optical function on the optical surface 21a. As the mirror 21, for example, a variable shape optical element that makes the shape of the optical surface variable is used.

  FIG. 2 is a schematic cross-sectional view showing the configuration of the deformable optical element unit 1 that deforms the optical element 2. In the optical element 2, a reflective film 22 is formed on the optical surface that is the surface of the mirror 21, and a correction film 23 is formed on the non-optical surface that is the back surface of the mirror 21. The optical element 2 is attached to the base 3 via a holding member 31. A plurality of actuators 4 for deforming and driving the mirror 21 are arranged on the back surface, which is the non-optical surface side of the optical element 2. The mirror 21 is deformed into a desired shape by driving the actuator 4.

  In a photolithography process in which a pattern on a reticle (mask) in semiconductor manufacturing is transferred to a wafer, an extremely fine pattern is imaged on the wafer, so that the influence of aberration of the optical system becomes a problem. In a semiconductor exposure apparatus that performs a photolithography process, imaging characteristics can be improved by using a deformable optical element that deforms a lens or mirror of an optical system.

  In general, in an optical element that requires high-precision shape accuracy, the optical element is designed to be as thick and rigid as possible in order to cope with deformation caused by gravity or deformation received from a lens barrel.

  On the other hand, in the case of a deformable optical element, as shown in FIG. 2, a plurality of actuators 4 are generally arranged on the optical element 2 that is thin and easily deformed, and the optical element 2 is deformed to control the shape of the optical element 2. doing. As described above, in the deformable optical element, the optical element 2 itself is deformed by the actuator 4, so that the optical element 2 is designed to have a small thickness and a low rigidity. The optical element 2 reduces the thrust of the actuator 4 by reducing the rigidity, and reduces adverse effects such as unnecessary heat generation of the actuator 4 and deformation of other structures due to the thrust of the actuator 4.

  As shown in FIG. 1, the mirror 21 using the deformable optical element is provided with an optical thin film such as an antireflection film or a reflection film 22 on the optical surface 21a in order to improve optical characteristics. The optical thin film is generally a multilayer film composed of a plurality of material layers, and has a thermal expansion coefficient different from that of the mirror 21. For this reason, the mirror 21 and the optical thin film are deformed like a bimetal due to a temperature change.

  Moreover, an optical thin film is formed on the mirror 21 by using a film forming means such as vapor deposition or sputtering, whereby an internal stress is generated between the mirror 21 and the optical thin film, and the optical element 2 is deformed.

  A deformable optical element used in a semiconductor exposure apparatus is required to have a very high shape accuracy. For this reason, the deformation due to the film formation of the optical thin film and the deformation due to the temperature change of the optical thin film and the mirror 21 affect the optical performance.

  In deformation by film formation, there is a method of reducing internal stress by forming an optical thin film. However, in order to reduce the internal stress, it is necessary to change the configuration of the optically ideal multilayer optical thin film to reduce the internal stress, and the optical performance is inferior to the ideal optical thin film. .

  In the deformation due to the difference in thermal expansion coefficient between the mirror 21 and the optical thin film, there is a method of highly managing the temperature. However, since exposure light with high intensity is incident on the mirror 21 in the exposure apparatus, it is difficult to manage the temperature.

  As other means, there is a method of correcting the deformation of the mirror 21 by driving the actuator 4 as shown in FIG. However, since the correction of the deformation due to the internal stress of the optical thin film is an offset correction, it is necessary to devote the limited stroke and thrust of the actuator 4 to the correction of the deformation.

  The internal stress of the optical thin film is sensitive to temperature, humidity, etc., and changes with time. For this reason, even when the deformation when the optical thin film is formed on the deformable optical element can be corrected by the actuator 4, the deformation of the deformable optical element can be prevented against further deformation during the subsequent operation of the apparatus. It is necessary to measure the shape. Since the shape measurement of the deformable optical element has various restrictions such as cost, it is desirable to drive the actuator 4 open without performing shape measurement. However, when the actuator 4 is open-driven, it is difficult to correct variations in internal stress of the optical thin film and deformation due to thermal expansion.

  For example, in the case of an optical element in which a thin film 25 is formed on a simple disk glass 6 as shown in FIG. 3, the deformation due to internal stress results in a simple curvature change that bends the disk into a spherical shape. For this reason, the film stress deformation can be corrected by adjusting the arrangement of the optical elements, or the drive can be corrected by the actuator 4 shown in FIG.

  On the other hand, as shown in FIG. 4, when the thin film 25 having a uniform thickness is formed in the deformable optical element 24 whose effective surface has a curvature and the thickness is not constant, due to internal stress and thermal expansion of the thin film 25. The deformation indicates a high-order deformation that is difficult to correct from the second order or higher. For this reason, it cannot be corrected by adjusting the arrangement of the optical elements, and the resolution becomes insufficient when the actuator 4 that deforms the deformable optical element 24 is driven.

  In the present embodiment, the above problem is solved by controlling the distribution state of the correction film formed on the non-optical surface of the optical element. Specifically, for example, as illustrated in FIG. 1, a correction film 23 that is concentrically divided into a plurality of regions from the center of the mirror 21 is provided on the non-optical surface 21 b of the deformable mirror 21. That is, the correction film 23 is provided separately on the non-optical surface 21b in a plurality of film regions 23-1, 23-2, 23-3, ... 23-n, .... Here, the distance d (j−k) between the arbitrary film region 23-j and the adjacent film region 23-k can be set to an arbitrary width in consideration of the internal stress distribution of the film. In this embodiment, the distance d (xy) between the film region 23-x formed outside the film regions 23-j and 23-k and the film region 23-y adjacent to the film region 23-x is the above-described distance. It is formed larger than d (j−k), and the distance between them is different.

  In this embodiment, the internal stress is distributed by adjusting the presence or absence of film formation. In the correction film 23, a non-film area 28 in which no film exists is formed between an arbitrary film area 23-j and a film area 23-k adjacent thereto. In order to form the non-film region 28 by forming the correction film 23, a masking 26 shown in FIG. When the correction film 23 is formed by the masking 26, a non-film region 28 as shown in FIG. 5B can be formed. The masking 26 may be a general masking tape or a material that prevents film adhesion. However, since there is a concern of chemical contamination of the high-vacuum environment of the film-forming vacuum chamber by the masking 26, it is desirable that the substance has little chemical contamination.

FIG. 6 is a schematic cross-sectional view showing a deformed state of the mirror 21 due to internal stress of the film when the thickness of the correction film 23 on the non-optical surface is made uniform. Since the thickness of the mirror 21 is reduced according to the outer periphery, the bimetal effect due to the internal stress of the mirror 21 and the film varies depending on the thickness of the mirror 21. Further, since the mirror 21 is a curved surface, the bimetal effect due to internal stress changes depending on the position in the radial direction. For this reason, even if a uniform film is formed on both the optical surface and the non-optical surface of the mirror 21, nonlinear deformation as shown in FIG. 6 remains.
Therefore, in the correction film 23 that contributes to the deformation in FIG. 6, it is possible to suppress the deformation of the mirror by providing a distribution of the internal stress so as to correct the deformation.

  FIG. 7 is a diagram for obtaining the masking arrangement from the deformation of the mirror 21 due to the film stress. FIG. 7A shows the deformation state of the mirror 21 when the thickness of the correction film 23 is uniform, FIG. 7B shows the deformation amount of FIG. 7A, and FIG. 7C shows the internal stress distribution for correcting the deformation of FIG. FIG. 6 is a layout view of a masking 26 for providing

  The internal stress generated in the correction film 23 is constant regardless of the radius, but since the mirror 21 is a curved surface and the thickness is not uniform, the mirror 21 exhibits a non-uniform deformation as shown in FIG. . In the range of K in FIG. 7B, the effect of the reflective film 22 is greater than that of the correction film 23, and therefore the mirror 21 exhibits a convex deformation on the reflective film side. On the other hand, in the range L in FIG. 7B, the influence of the correction film 23 is larger than that of the reflection film 22, and therefore the mirror 21 shows a convex deformation on the correction film side. That is, if the internal stress of the correction film 23 can be increased in the range K and the internal stress of the correction film 23 can be reduced in the range L, the deformation of the mirror 21 shown in FIG. 7B can be corrected.

  The internal stress of the correction film 23 is controlled by masking 26 shown in FIG. 7C for each of the K and L regions. Where the internal stress of the correction film 23 is to be reduced, the width in the radial direction of the masking 26 is widened, and where the internal stress of the correction film 23 is to be increased, the width of the masking 26 is narrowed. Here, the duty ratio in the radial direction of the correction film 23 in FIG. 7A in which the thickness of the correction film 23 is uniform without being divided into a plurality of regions is 100%, whereas the masking in FIG. 7C is performed. The duty ratio of the correction film 23 formed by H.26 is about 50%. For this reason, it is desirable to increase the thickness of the correction film 23 in order to compensate for a decrease in the resultant force of the internal stress on the non-optical surface side caused by a decrease in the duty ratio due to the masking 26. When the duty ratio of the correction film 23 is 50%, a decrease in the resultant force of the internal stress of the correction film 23 can be compensated by setting the film thickness of the correction film 23 to 200%.

Next, the setting of the width of the masking 26 will be described. FIG. 8 is a diagram for explaining the arrangement of the masking 26. 8A shows an example of the width of the set masking 26, FIG. 8B shows the state of the correction film 23 after removing the masking 26, and FIG. 8C shows the internal stress distribution of the correction film 23. FIG. .
When it is desired to give an internal stress distribution that becomes a dashed sine curve shown in FIG. 8C, the ratio of the width of the masking 26 shown in FIG. To set. The light-dark width D, which is the sum of dimensions of the unmasked portion adjacent to the arbitrary masking 26, and the size ratio thereof are included in the spatial frequency of the desired internal stress distribution (ie, the unit length in the structure having a spatial period). Set according to the number of repetitions of the structure. That is, in the area above the horizontal axis in the sin curve of FIG. 8C, the influence of the reflection film 22 is greater than that of the correction film 23 in the deformation of the mirror 21, so that a convex deformation is shown on the reflection film 22 side. For this reason, in order to increase the internal stress of the correction film 23, the width of the portion without the masking 26 is increased in the light / dark width D of FIG. As a result, as shown in FIG. 8B, the distance between the correction films 23 is narrowed, resulting in a region where the correction films 23 are densely formed. On the other hand, in the region below the horizontal axis in the sine curve of FIG. 8C, the deformation of the mirror 21 is less affected by the reflection film 22 than the correction film 23, and the convex deformation on the correction film 23 side. Indicates. For this reason, in order to reduce the internal stress of the correction film 23, the width of the portion without the masking 26 in the light / dark width D ′ of FIG. As a result, as shown in FIG. 8B, the distance between the correction films 23 is widened, resulting in a region where the correction films 23 are formed sparsely.

  However, in order to satisfy a high spatial frequency, it is desirable to set in consideration of an arrangement error of the masking 26. If the arrangement error of the masking 26 is 0.5 mm, 5 mm, which is ten times the arrangement error, can be set as the light / dark width. By reducing the placement error of the masking 26, the light / dark width can be narrowed and the spatial frequency can be increased.

  Next, a method for manufacturing the optical element 2 according to this embodiment will be briefly described. FIG. 9 is a flowchart illustrating a method for manufacturing the optical element 2. First, the shape of the optical surface 21a shown in FIG. 1 after film formation is specified (S11). Next, the distribution of the correction film 23 on the non-optical surface 21b is determined in consideration of the thickness of the correction film 23 (S12). Further, the correction film 23 is formed on the non-optical surface 21b using the masking 26 (S13). Finally, the shape of the optical surface 21a is inspected (S14).

  Since the correction film 23 is provided in a plurality of regions on the non-optical surface 21b of the optical element 2, the internal stress can be effectively controlled. For example, in a deformable optical element having an effective surface with a curvature and a thickness that is not constant in the radial direction, a complicated deformation that has a plurality of higher-order inflection points may occur. Such complicated deformation can be corrected by dividing the region into concentric regions. Therefore, the deformation of the optical element 2 can be corrected at a high spatial frequency. Moreover, the deformation of the optical element 2 can be corrected at a higher spatial frequency by changing the dimensional ratio of the adjacent film region 23-n and non-film region 28 in the concentric region in the radial direction of the optical element 2.

  Furthermore, in the method of depositing a correction film by vapor deposition or sputtering using a film thickness distribution control plate or the like, deposition of film raw material material on an optical element is performed in consideration of various conditions such as temperature and input energy at the time of film formation. Thickness and other conditions must be predicted and studied in detail. Therefore, detailed condition adjustment work is required. On the other hand, in the method according to the present embodiment, the film width distribution of the correction film 23 is not formed by forming the film region 23-n and the non-film region 28 using the masking 26 instead of controlling the film formation conditions. To control. For this reason, complicated condition adjustment is unnecessary and manufacture is easy.

  Further, by applying the optical element 2 according to the present embodiment to an exposure apparatus that performs a photolithography process for transferring a pattern on a reticle (mask) to a wafer in semiconductor manufacturing, it is caused by temperature change or humidity change during exposure. The imaging characteristics can be improved by suppressing the deterioration of aberration.

[Second Embodiment]
FIG. 10 is a schematic cross-sectional view showing the configuration of the optical element 2 ′ according to the second embodiment. In this embodiment, the same components as those of the optical element 2 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the optical element 2 ′ according to the present embodiment, the correction film 23 is provided with a desired thickness for each region on the non-optical surface 21 b of the mirror 21. In order to change the thickness, for example, a multilayer film is used. As shown in FIG. 10, in the A region, the correction film 23 is formed of a three-layer film of correction films 23a, 23b, and 23c, in the B region, it is formed of a two-layer film of correction films 23a and 23b, and in the C region. The correction film 23a is a single layer film. As described above, the correction film 23 can have a different thickness for each region, so that a finer internal stress distribution can be given to the mirror 21 not only in the in-plane direction but also in the thickness direction.

  In the correction film 23 having a different thickness depending on the region as shown in FIG. 10, a mask 26 having a predetermined pattern is applied to the non-optical surface 21 b of the mirror 21 to first form a correction film 23 a as the first layer. Next, a mask 26 having a pattern different from that of the first layer is applied to form a correction film 23b of the second layer, and further, masking 26 having a pattern different from that of the first layer and the second layer is applied. Then, a third-layer correction film 23c is formed.

  The correction films 23a, 23b, and 23c can be formed from different materials. However, it is preferable to use the same material for the correction film 23a and the reflective film 22 which are the layers having the largest film formation area among the correction films 23, because the influence of the coefficient of thermal expansion can be offset.

  As described above, in the optical element 2 ′ according to the present embodiment, the correction film 23 is a multilayer film, and the integrated thickness of the multilayer correction film is changed depending on the region, thereby giving a finer internal stress distribution to the mirror 21. It is possible.

[Third Embodiment]
FIG. 11 is a schematic cross-sectional view showing the configuration of the optical element 2 ″ according to the third embodiment. In this embodiment, the same components as those of the optical element 2 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.
In the optical element 2 '' according to the present embodiment, the adhesion improving film 33 for improving the adhesion between the non-optical surface 21b and the correction film 23 between the non-optical surface 21b of the mirror 21 and the correction film 23. Is provided.

  As shown in FIG. 11, it is desirable that the adhesion improving film 33 be a continuous film having a uniform thickness without being divided into a plurality of regions. The adhesion improving film 33 has an effect of improving the adhesion to the last, and is not formed for the purpose of changing the internal stress distribution unlike the correction film 23.

  FIG. 12 is a schematic cross-sectional view showing a configuration of an optical element 2 ″ ″ according to a modification of the third embodiment. In the optical element 2 ″ ″ according to the present embodiment, a protective film 35 is provided so as to cover the entire surface of the correction film 23. From the viewpoint of protecting the correction film 23 and the mirror 21, the protective film 35 is desirably provided on the entire surface of the correction film 23 and the mirror 21 without dividing the film into a plurality of regions. Note that the protective film 35 is formed only for the purpose of protecting the correction film 23 and the mirror 21, and is not formed for the purpose of changing the internal stress distribution unlike the correction film 23.

  In designing the masking 26 in the case of providing the adhesion improving film 33 and the protective film 35, first, the configuration of the mirror 21, the reflection film 22, the adhesion improving film 33, the protective film 35, and the uniform correction film 23 without the masking 26. The deformation of the mirror 21 at is determined. Next, the distribution of the masking 26 is designed so as to correct this deformation.

[Fourth Embodiment]
FIG. 13 is a schematic view showing the arrangement of the exposure apparatus 100 according to the fourth embodiment.
The exposure apparatus 100 includes a holding device 110, an illumination optical system 120, a projection optical system 130, a mask stage 140 that can move while holding a mask, and a substrate stage 150 that can move while holding a substrate. . The substrate exposure process is executed by a control unit (not shown) controlling each unit. In FIG. 13, the Y axis is taken in the scanning direction of the reticle and the substrate during exposure in the plane perpendicular to the Z axis, which is the vertical direction, and the X axis is taken in the non-scanning direction orthogonal to the Y axis. The substrate is a substrate to be processed made of, for example, a glass material and having a surface coated with a photosensitive agent (resist). Further, the reticle is an original plate made of, for example, a glass material and having a pattern (a fine uneven pattern) to be transferred to the substrate.

  Since the holding device 110 is configured in the same manner as the deformable optical element unit 1 shown in FIG. 2, the same components are denoted by the same reference numerals and description thereof is omitted. The holding device 110 includes a base 3, a holding member 31 that supports the optical element 2, a plurality of actuators 4, and a detection unit 114. The plurality of actuators 4 are controlled by a control unit (not shown). A part including the center of the optical element 2 (hereinafter referred to as a central portion) is fixed to the base 3 via a holding member 31.

The plurality of actuators 4 are disposed between the optical element 2 and the base 3, and apply force to a plurality of locations on the back surface of the optical element 2.
Each of the plurality of actuators 4 includes, for example, a mover 4a and a stator 4b that are not in contact with each other, and can apply a force to each position on the back surface of the optical element 2. As the actuator 4, for example, a voice coil motor or a linear motor can be used. When a voice coil motor is used as the actuator 4, a coil as the stator 4 b can be fixed to the base 3, and a magnet as the mover 4 a can be fixed to the back surface of the optical element 2. Each actuator 4 can generate a Lorentz force between the coil and the magnet by supplying a current to the coil, and can apply a force to each part of the optical element 2. In this embodiment, there is a gap of about 0.1 mm between the mover 4a and the stator 4b, and they are not in contact with each other.

  The detection unit 114 detects the distance between the optical element 2 and the base 3. The detection unit 114 can include a plurality of sensors (for example, electrostatic capacitance sensors) that respectively detect the distance between the optical element 2 and the base 3. By providing the detection unit 114 in this way, feedback control of the plurality of actuators 4 can be performed based on the detection result by the detection unit 114, and the reflection surface of the optical element 2 can be accurately deformed to the target shape. .

  Light emitted from a light source (not shown) included in the illumination optical system 120 forms, for example, an arc-shaped illumination area long in the X direction on the mask by a slit (not shown) included in the illumination optical system 120. be able to. The mask and the substrate are respectively held by the mask stage 140 and the substrate stage 150, and are arranged at optically conjugate positions (object plane and image plane positions of the projection optical system 130) via the projection optical system 130. The The projection optical system 130 has a predetermined projection magnification, and projects the pattern formed on the mask onto the substrate. Then, the mask stage 140 and the substrate stage 150 are relatively moved in a direction (for example, the Y direction) parallel to the object plane of the projection optical system 130 at a speed ratio corresponding to the projection magnification of the projection optical system 130. Thereby, the scanning exposure which scans a slit light on a board | substrate can be performed, and the pattern formed in the mask can be transcribe | transferred to a board | substrate.

  The projection optical system 130 includes a lens barrel that holds the plane mirrors 131 and 133, the convex mirror 132, and the optical element 2. The exposure light emitted from the illumination optical system 120 and transmitted through the mask is bent in the optical path by the plane mirror 131 and enters the upper part of the reflection surface of the optical element 2. The exposure light reflected by the upper part of the optical element 2 is reflected by the convex mirror 132 and enters the lower part of the reflecting surface of the optical element 2. The exposure light reflected by the lower part of the optical element 2 is bent on the optical path by the plane mirror 133 and forms an image on the substrate. In the projection optical system 130 configured in this way, the surface of the convex mirror 132 becomes an optical pupil.

(Embodiment related to article manufacturing method)
The method for manufacturing an article according to the present embodiment is suitable for manufacturing an article such as a microdevice such as a semiconductor device or an element having a fine structure, for example. In the method for manufacturing an article according to the present embodiment, a latent image pattern is formed on the photosensitive agent applied to the substrate using the above-described exposure apparatus (a step of exposing the substrate), and the latent image pattern is formed in this step. Developing the substrate. Further, the manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, and the like). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

  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.

  For example, in each of the embodiments described above, correction of optical element deformation caused by internal stress due to film formation of the optical film has been described. However, this correction is caused by a difference in thermal expansion coefficient between the optical element and the optical film. It is also possible to cope with optical element deformation. In the case of deformation of the optical element due to the difference in thermal expansion coefficient between the optical element and the optical film, it can be dealt with by replacing the deformation in each of the above embodiments with the deformation at a certain temperature difference.

DESCRIPTION OF SYMBOLS 1 Variable shape optical element unit 2 Optical element 3 Base 4 Actuator 6 Disc glass 21 Mirror 21a Optical surface 21b Non-optical surface 22 Reflective film 23 Correction film | membrane 23-n Film area | region 24 Variable shape optical element 25 Thin film 26 Masking 28 Non-film area | region 31 Holding member 33 Adhesion improving film 35 Protective film

Claims (8)

An optical element body having an optical surface provided with a reflective film, and a non-optical surface opposite to the optical surface;
A plurality of correction films provided on the non-optical surface side for correcting the shape of the optical element body,
The optical element, wherein the plurality of correction films are provided in a plurality of different regions on the non-optical surface side.   The optical element body has a disk shape with a curvature and a radial thickness that is not constant, and the plurality of correction films are concentrically formed in a plurality of regions from the center of the optical element body. The optical element according to claim 1, wherein the optical element is provided separately.   The dimensional ratio between a region where the correction film is provided and a region adjacent to the correction film and where the correction film is not formed varies in a radial direction. Optical element.   The optical element according to claim 1, wherein the correction film is a multilayer film.   The optical element according to claim 4, wherein at least one film of the multilayer film and the reflective film are made of the same material.   2. The optical element according to claim 1, wherein a film is provided between the non-optical surface of the optical element body and the correction film so that the non-optical surface and the correction film are in close contact with each other. An exposure apparatus for exposing a substrate,
The optical element according to any one of claims 1 to 6,
A holding device for holding the optical element;
Including a projection optical system,
Exposing the substrate through the projection optical system;
An exposure apparatus characterized by that. A step of exposing the substrate using the exposure apparatus according to claim 7;
Developing the substrate exposed in the step;
A method for producing an article comprising:

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