KR102230464B1 - Optical element, exposure apparatus, and article manufacturing method - Google Patents

Abstract

It provides an optical element which is advantageous for correcting a complex deformation having a plurality of inflection points.
The optical element 2 is provided on the side of the non-optical surface 21b, the mirror 21 having an optical surface 21a on which a reflective film is provided, and a non-optical surface 21b opposite to the optical surface 21a, A plurality of correction films 23 for correcting the shape of the mirror 21 are provided. The plurality of correction films 23 are provided by being divided into a plurality of regions different from each other on the non-optical surface 21b side.

Description

Optical element, exposure apparatus, and manufacturing method of article TECHNICAL FIELD {OPTICAL ELEMENT, EXPOSURE APPARATUS, AND ARTICLE MANUFACTURING METHOD}

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

In a projection exposure apparatus used for manufacturing a semiconductor, in order to cope with the deterioration of aberration due to temperature change during exposure, there is a technique of correcting aberration by varying the shape of a reflective surface of a mirror used in an optical system. An optical element having a variable shape is formed to have a thin thickness (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 of correcting the deformation of a mirror, a thin film is formed on the non-optical surface opposite to the reflective surface (i.e., optical surface) of the mirror, and the internal stress on the optical surface is canceled by the internal stress on the non-optical surface. There is a method of correcting the distortion of the mirror by doing so. For example, in the method described in Patent Literature 1, a non-optical thin film is formed at an arbitrary thickness depending on the portion using a control panel for controlling the film thickness distribution to correct the deformation of the optical element.

Japanese Patent Application Publication No. 2005-19485

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

It is an object of the present invention to provide an optical element which 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 provides an optical element body having an optical surface on which a reflective film is installed, and a non-optical surface opposite to the optical surface, and a plurality of optical elements installed on the non-optical surface side to correct the shape of the optical element body. An optical element having a correction film of, wherein the plurality of correction films are divided into a plurality of regions different from each other on the non-optical surface side and provided.

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

1 is a schematic cross-sectional view showing a configuration of an optical element according to a first embodiment.
2 is a schematic cross-sectional view showing the configuration of a variable shape optical element unit.
3 is a schematic diagram showing a state of deformation due to a thin film in an original glass.
Fig. 4 is a schematic diagram showing deformation by a thin film in a variable shape optical element having a curved surface and a distribution in thickness.
5 is a cross-sectional view showing an arrangement of masking for generating a region of a correction film.
Fig. 6 is a schematic cross-sectional view showing a state in which the mirror is deformed due to internal stress of the film when the thickness of the correction film on the non-optical surface is made uniform over the entire surface.
7 is a diagram for obtaining an arrangement of masking from deformation of a mirror due to film stress.
8 is a diagram for describing an arrangement of masking.
9 is a flowchart illustrating a method of manufacturing an optical element.
10 is a schematic cross-sectional view showing a configuration of an optical element according to a second embodiment.
11 is a schematic cross-sectional view showing a configuration of an optical element according to a third embodiment.
12 is a schematic cross-sectional view showing a configuration of an optical element according to a modification of the third embodiment.
13 is a schematic diagram showing a configuration of an exposure apparatus according to a fourth embodiment.

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

[First embodiment]

1 is a schematic cross-sectional view showing a configuration of an optical element 2 according to a first embodiment of the present invention. The optical element 2 includes a mirror (that is, an optical element body) 21 having an optical surface 21a that reflects light, and a non-optical surface 21b on the opposite side to the optical surface 21a, and a non-optical surface. It is provided on 21b and is provided with a correction film 23 as a 1st film for correcting the deformation|transformation of the shape of the mirror 21. The correction film 23 is composed of a plurality of film regions 23-n, as described later. Further, the optical element 2 is provided with a reflective 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.

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

In a photolithography process of transferring a pattern on a reticle (mask) to a wafer in semiconductor manufacturing, in order to image a very fine pattern on the wafer, an influence such as aberration of the optical system becomes a problem. In a semiconductor exposure apparatus performing a photolithography process, imaging characteristics can be improved by using a variable shape optical element that deforms a lens or a mirror of an optical system.

In general, in an optical element requiring high accuracy in shape, in order to cope with deformation due to gravity or deformation received from a barrel, the thickness of the optical element is made as thick as possible to increase rigidity.

On the other hand, in the case of a variable shape optical element, as shown in FIG. 2, a plurality of actuators 4 are disposed in the optical element 2, which is generally thin and easily deformable, and the optical element 2 is deformed to The shape of the element 2 is controlled. In this way, in the variable shape optical element, since the optical element 2 itself is deformed by the actuator 4, the thickness of the optical element 2 is reduced to reduce rigidity. The optical element 2 reduces the thrust of the actuator 4 by lowering the rigidity, thereby reducing 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, in the mirror 21 using the variable shape optical element, an optical thin film such as an antireflection film or a reflective film 22 is provided on the optical surface 21a in order to improve optical properties. The optical thin film is generally a multilayer film including a plurality of material layers, and has a different coefficient of thermal expansion from the mirror 21. For this reason, the mirror 21 and the optical thin film exhibit the same deformation|transformation as a bimetal by temperature change.

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

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

In the deformation caused by film formation, there is a method of reducing internal stress by film formation of 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 that of the ideal optical thin film.

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

As another means, there is a method of correcting the distortion of the mirror 21 by driving the actuator 4 as shown in FIG. 2. However, since correction of the deformation due to the internal stress of the optical thin film is an offset correction, it is necessary to devote a limited stroke or thrust of the actuator 4 to correction of the deformation.

The internal stress of the optical thin film is sensitive to temperature or humidity and changes with time. For this reason, although it is possible to correct the deformation when the optical thin film is formed on the variable shape optical element with the actuator 4, it is necessary to measure the shape of the variable shape optical element for additional deformation such as during operation of the device after that. There is. Since shape measurement of the variable shape optical element has various restrictions such as cost, it is preferable to open the actuator 4 without performing shape measurement. However, in the open drive of the actuator 4, it is difficult to correct fluctuations in internal stress of the optical thin film or 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 original glass 6 shown in Fig. 3, deformation due to internal stress results in a simple change in curvature of bending the original plate into a spherical shape. For this reason, it is possible to correct the film stress deformation by adjusting the arrangement of the optical elements, or to correct the driving by the actuator 4 shown in FIG. 2.

On the other hand, as shown in FIG. 4, in the variable shape optical element 24 having a curvature of an effective surface and a non-uniform thickness, when a thin film 25 having a uniform thickness is formed, the thin film 25 Deformation due to internal stress and thermal expansion exhibits a high-dimensional deformation that is difficult to correct more than the second order. For this reason, it cannot be corrected by adjustment of the arrangement of the optical elements, and the resolution becomes insufficient by driving the actuator 4 that deforms the variable shape optical element 24.

In this 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, as shown in FIG. 1, for example, on the non-optical surface 21b of the mirror 21 having a variable shape, a correction film divided into a plurality of regions concentrically from the center of the mirror 21 ( 23) is installed. That is, the correction film 23 is divided and provided in a plurality of film regions 23-1, 23-2, 23-3,… 23-n, …… on the non-optical surface 21b. Here, the distance d(j-k) between the arbitrary film region 23-j and the film region 23-k adjacent thereto can be set to an arbitrary width in consideration of the internal stress distribution of the film and the like. In addition, 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 thereto is the distance d It is formed larger than (jk), and the interval between the two is made to be different.

In this embodiment, distribution is given to the internal stress by adjusting the presence or absence of film formation. In the correction film 23, between an arbitrary film region 23-j and a film region 23-k adjacent thereto is a non-film region 28 in which no film is present. In order to form this non-film region 28 in the formation of the correction film 23, a masking 26 shown in Fig. 5A is provided. When the correction film 23 is formed by the masking 26, the 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 risk of chemical contamination of the high vacuum environment of the vacuum tank for film formation by the masking 26, it is preferable that the material is less chemically contaminated.

6 is a schematic cross-sectional view showing a state of deformation of the mirror 21 according to the internal stress of the film when the thickness of the correction film 23 on the non-optical surface is made uniform throughout the entire surface. Since the thickness of the mirror 21 is thinned along the outer circumference, the bimetal effect due to internal stress of the mirror 21 and the film changes according to the thickness of the mirror 21. In addition, since the mirror 21 is curved, the bimetal effect according to the internal stress varies depending on the position in the radial direction. For this reason, even if a uniform film is formed on the entire optical surface and the non-optical surface of the mirror 21, a nonlinear deformation as shown in Fig. 6 remains.

Therefore, in the correction film 23 contributing to the deformation of Fig. 6, it is possible to suppress the deformation of the mirror by distributing the internal stress so as to correct the deformation.

7 is a diagram for determining the arrangement of masking from deformation of the mirror 21 due to film stress. 7(A) is a deformation state of the mirror 21 when the thickness of the correction film 23 is uniform, FIG. 7(B) is a deformation amount of FIG. 7(A), and FIG. 7(C) is It is a layout view of the masking 26 for imparting an internal stress distribution for correcting the deformation of Fig. 7B.

The internal stress generated in the correction film 23 is constant regardless of the radius. Since the mirror 21 is curved and has a non-uniform thickness, the mirror 21 undergoes non-uniform deformation as shown in FIG. 7B. Show. In the range of K in Fig. 7B, since the reflective film 22 has a greater influence than the correction film 23, the mirror 21 exhibits a convex deformation toward the reflective film side. On the other hand, in the range of L in Fig. 7B, since the influence of the correction film 23 is greater than that of the reflective film 22, the mirror 21 exhibits convex deformation toward the correction film side. That is, if the internal stress of the correction film 23 can be increased in the range of K and the internal stress of the correction film 23 can be reduced in the range of L, the mirror 21 shown in FIG. It becomes possible to correct the distortion.

The internal stress of the correction film 23 is controlled for each of the regions K and L by the masking 26 shown in Fig. 7C. Where the internal stress of the correction layer 23 is to be reduced, the width of the masking 26 in the radial direction is increased, and where the internal stress of the correction layer 23 is to be strengthened, the width of the masking 26 is narrowed. Here, while 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%, Fig. 7C The duty ratio of the correction film 23 formed by the masking 26 of is about 50%. For this reason, it is desirable to increase the thickness of the correction film 23 in order to compensate for the decrease in the resultant force of the internal stress on the non-optical surface side due to the 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 for by making the film thickness of the correction film 23 200%.

Next, setting of the width of the masking 26 will be described. 8 is a diagram for explaining the arrangement of the masking 26. FIG. 8A shows an example of the width of the masking 26 set, FIG. 8B shows the state of the correction film 23 after removing the masking 26, and FIG. 8C shows the correction film 23. ) Shows the internal stress distribution.

In the case of applying an internal stress distribution that becomes a sin curve of a broken line shown in Fig. 8C, the width of the masking 26 shown in Fig. 8A and the width of the area without masking adjacent thereto are It is set in consideration of the rain. The contrast width D, which is the sum of dimensions of an arbitrary masking 26 and the adjacent unmasked area, and their dimensional ratio, are included in the spatial frequency of the desired internal stress distribution (that is, the unit length in a structure having a spatial period). It is set according to the degree of repetition of the structure). That is, in the region above the horizontal axis in the sin curve of FIG. 8C, the influence of the reflective film 22 is greater than that of the correction film 23 in the deformation of the mirror 21, so that the convex deformation toward the reflective film 22 side. Represents. For this reason, in order to increase the internal stress of the correction film 23, the width of the portion without the masking 26 in the contrast width D in Fig. 8A is increased. As a result, as shown in Fig. 8B, the gap between the correction films 23 is narrowed to form a region in which the correction films 23 are densely formed. On the other hand, in the region below the horizontal axis in the sin curve of Fig. 8C, the influence of the reflection film 22 is smaller than that of the correction film 23 in the deformation of the mirror 21, so that the correction film 23 side Represents convex deformation. 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 contrast width D'in Fig. 8A is reduced. As a result, as shown in Fig. 8B, the gap between the correction films 23 is widened to form a region where the correction films 23 are formed small.

However, in order to satisfy a high spatial frequency, it is preferable to set it in consideration of the arrangement error of the masking 26. If the arrangement error of the masking 26 is 0.5 mm, 5 mm, which is 10 times the arrangement error, can be set as the contrast width. By reducing the arrangement error of the masking 26, the contrast width can be narrowed and the spatial frequency can be increased.

Next, a brief description will be given of a method of manufacturing the optical element 2 according to the present embodiment. 9 is a flowchart illustrating a method of 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 while considering the thickness of the correction film 23 (S12). Further, a correction film 23 is formed on the non-optical surface 21b by using the masking 26 (S13). Finally, the shape of the optical surface 21a is inspected (S14).

Since the correction film 23 is divided into a plurality of regions and provided on the non-optical surface 21b of the optical element 2, internal stress can be effectively controlled. For example, complex deformation having a plurality of high-dimensional inflection points may occur in a variable shape optical element, etc., where the effective surface has a curvature and the thickness is not constant in the radial direction, but a plurality of the correction film 23 By dividing the area of into concentric circles, these complex deformations can be corrected. Accordingly, the deformation of the optical element 2 can be corrected at a high spatial frequency. In addition, by changing the dimensional ratio of the adjacent film region 23-n and the non-film region 28 in the concentric circular region in the radial direction of the optical element 2, the deformation of the optical element 2 is reduced to a higher spatial frequency. It can be corrected with.

In addition, in the method of forming a correction film by vapor deposition or sputtering using a film thickness distribution control panel, etc., various conditions such as temperature and input energy at the time of film formation are taken into consideration, such as the deposition thickness of the film raw material on the optical element. The condition must be predicted and reviewed in detail. Therefore, careful condition adjustment work is required. On the other hand, in the method according to the present embodiment, the film formation conditions are not controlled, but the film width of the correction film 23 is formed by forming the film regions 23-n and the non-film regions 28 using the masking 26. Control the distribution of For this reason, complicated condition adjustment is unnecessary, and manufacturing is easy.

In addition, by applying the optical element 2 according to the present embodiment to an exposure apparatus that performs a photolithography process in which a pattern on a reticle (mask) in semiconductor manufacturing is transferred to a wafer, it is caused by a change in temperature or humidity during exposure. It is possible to suppress the deterioration of the aberration to improve the forming characteristics.

[Second Embodiment]

10 is a schematic cross-sectional view showing the configuration of an 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 descriptions thereof are omitted.

In the optical element 2'according to the present embodiment, on the non-optical surface 21b of the mirror 21, the correction film 23 is provided with a desired thickness for each region. In order to change the thickness, for example, a multilayer film is used. As shown in Fig. 10, in the region A, the correction film 23 is formed of a three-layer film of the correction films 23a, 23b, and 23c, and in the region B, the correction film 23 is formed of a two-layer film of the correction films 23a, 23b. , In the region C, it is formed as a single layer film of the correction film 23a. In this way, it is possible to give the mirror 21 a finer internal stress distribution not only in the in-plane direction but also in the thickness direction by making the correction film 23 a different thickness for each region.

The correction film 23 having a different thickness depending on the region shown in FIG. 10 is subjected to masking 26 of a predetermined pattern on the non-optical surface 21b of the mirror 21, and first, the correction film 23a as the first layer. To the tabernacle. Subsequently, masking 26 of a pattern different from that of the first layer is applied to form a correction layer 23b of the second layer, and masking 26 of different patterns is performed on the first and second layers. Thus, a third-layer correction film 23c is formed.

The correction films 23a, 23b, and 23c can be formed of different materials, respectively. 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-forming area among the correction films 23, since the influence due to the coefficient of thermal expansion can be canceled out.

As described above, in the optical element 2'according to the present embodiment, the correction film 23 is a multilayered film, and by changing the integrated thickness of the multilayered correction film according to the region, a more detailed internal stress distribution is reduced by the mirror 21 ) Is possible.

[Third Embodiment]

Fig. 11 is a schematic cross-sectional view showing a configuration of an 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. The description is omitted.

In the optical element 2" according to the present embodiment, 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 improved. An adhesion-improving film 33 for this is provided.

As shown in FIG. 11, the adhesion-improving film 33 is preferably made continuously without being divided into a plurality of regions, and a film having a uniform thickness. In addition, the adhesion-improving film 33 has an effect of improving adhesion to the last, and is not formed for the purpose of changing the internal stress distribution like the correction film 23.

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 preferably provided on the entire surface of the correction film 23 and the mirror 21 without dividing the film into a plurality of regions. Further, the protective film 35 is formed for the purpose of protecting the correction film 23 and the mirror 21 to the last, and is not formed for the purpose of changing the internal stress distribution like the correction film 23.

In the design of the masking 26 when the adhesion improving film 33 or the protective film 35 is provided, first, the mirror 21, the reflective film 22, the adhesion improving film 33, the protective film 35, and masking The distortion of the mirror 21 in the same configuration as the uniform correction film 23 without (26) is obtained. Next, the distribution of the masking 26 is designed to correct this distortion.

[Fourth embodiment]

13 is a schematic diagram showing a configuration of an exposure apparatus 100 according to a 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 is movable by holding a mask, and a substrate that is movable by holding a substrate. It includes a stage 150. The exposure processing of the substrate is performed 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 substrate during exposure in a 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. In addition, the substrate is made of glass, for example, and is a substrate to be processed on which a photosensitive agent (resist) is applied to the surface. In addition, the reticle is made of glass, for example, and is an original plate on which a pattern (fine uneven pattern) to be transferred is formed on a substrate.

Since the holding device 110 is configured in the same manner as the variable shape optical element unit 1 shown in Fig. 2, the same components are denoted by the same reference numerals, and the description thereof is omitted. The holding device 110 includes a base 3, a holding member 31 supporting 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 (hereinafter, the center) including the center of the optical element 2 is fixed to the base 3 through the holding member 31.

The plurality of actuators 4 are disposed between the optical element 2 and the base 3, and apply a force to a plurality of locations on the rear surface of the optical element 2, respectively.

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 location on the rear surface of the optical element 2. As the actuator 4, for example, a voice coil motor, a linear motor, or the like can be used. In the case of using a voice coil motor as the actuator 4, the coil as the stator 4b is fixed to the base 3, and the magnet as the mover 4a can be fixed to the rear surface of the optical element 2. Further, each actuator 4 generates a Lorentz force between the coil and the magnet by supplying current to the coil, so that a force can be applied to each location of the optical element 2. In this embodiment, there is a gap of about 0.1 mm between the movable element 4a and the stator 4b, and both are not in contact.

The detection unit 114 detects the distance between the optical element 2 and the base 3. The detection unit 114 may include a plurality of sensors (eg, capacitive sensors) that respectively detect the distance between the optical element 2 and the base 3. By providing the detection unit 114 in this way, it is possible to perform feedback control of the plurality of actuators 4 based on the detection result by the detection unit 114, thereby deforming the reflective surface of the optical element 2 to a target shape with high precision. I can.

Light emitted from a light source (not shown) included in the illumination optical system 120 is, for example, a long arc-shaped illumination area in the X direction by a slit (not shown) included in the illumination optical system 120. It can be formed on the mask. The mask and the substrate are held by the mask stage 140 and the substrate stage 150, respectively, and are optically almost conjugated through the projection optical system 130 (the position of the object surface and the image surface of the projection optical system 130). ). The projection optical system 130 has a predetermined projection magnification and projects a pattern formed on the mask onto a substrate. In addition, the mask stage 140 and the substrate stage 150 are moved relatively in a direction parallel to the object plane of the projection optical system 130 (for example, in the Y direction) and at a speed ratio according to the projection magnification of the projection optical system 130 Let it. Thereby, scanning exposure in which the slit light is scanned on the substrate is performed, and the pattern formed on the mask can be transferred to the substrate.

The projection optical system 130 is constituted by planar mirrors 131 and 133, a convex mirror 132, and a barrel for holding the optical element 2. The exposure light emitted from the illumination optical system 120 and transmitted through the mask is bent in an optical path by the planar mirror 131 and enters the upper part of the reflective surface of the optical element 2. The exposure light reflected from the upper part of the optical element 2 is reflected by the convex mirror 132 and is incident on the lower part of the reflective surface of the optical element 2. As for the exposure light reflected from the lower part of the optical element 2, the optical path is bent by the planar mirror 133, and an image is formed 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 relating to the manufacturing method of the article)

The manufacturing method of 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. The article manufacturing method of this embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate by using the exposure apparatus (a step of exposing the substrate), and a step of developing a substrate on which the latent image pattern is formed in this step. do. In addition, such a manufacturing method includes other well-known processes (oxidation, film formation, vapor deposition, doping, planarization, etching, resist peeling, dicing, bonding, packaging, etc.). The article manufacturing method of the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared to the conventional method.

As described above, preferred embodiments of the present invention have been described, but the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist.

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

1: variable shape optical element unit
2: optical element
3: bass
4: actuator
6: disc glass
21: mirror
21a: optical surface
21b: non-optical surface
22: reflective film
23: correction film
23-n: membrane area
24: variable shape optical element
25: thin film
26: masking
28: non-membrane area
31: holding member
33: adhesion improvement film
35: shield

Claims (8)

An optical element body having an optical surface on which a reflective film is provided, and a non-optical surface opposite to the optical surface,
An optical element provided on the non-optical surface side and provided with a plurality of correction films for correcting the shape of the optical element body,
The plurality of correction films are provided on the non-optical surface side with a region in which the correction film is not provided between them,
A gap between the first and second correction layers disposed outside the optical element body and adjacent to each other, and a third and fourth correction layers disposed inside the first and second correction layers and adjacent to each other. An optical element characterized in that the intervals of the correction films are different. The optical element body according to claim 1, wherein the optical element body has a shape of a disc having a curvature and a thickness in a radial direction is not constant, and the plurality of correction films are provided concentrically from the center of the optical element body. Optical element, characterized in that. The optical element according to claim 1, wherein a distance between the first correction film and the second correction film is larger than a distance between the third correction film and the fourth correction film. The optical device of claim 1, wherein the correction layer is a multilayer layer. The optical element according to claim 4, wherein at least one of the multilayer films and the reflective film are made of the same material. The optical element according to claim 1, wherein a film is provided between the non-optical surface and the correction film of the optical element body to make the non-optical surface and the correction film in close contact with each other. It is an exposure apparatus that exposes a substrate,
An optical element having an optical surface on which a reflective film is installed, an optical element body having a non-optical surface opposite to the optical surface, and a plurality of correction films installed on the non-optical surface side for correcting the shape of the optical element body, and , The plurality of correction films, an optical element provided on the non-optical surface side with a region in which the correction film is not provided, and
Holding device for holding the optical element
Including a projection optical system comprising a,
Exposing the substrate through the projection optical system,
A gap between the first and second correction layers disposed outside the optical element body and adjacent to each other, and a third and fourth correction layers disposed inside the first and second correction layers and adjacent to each other. An exposure apparatus characterized in that the intervals of the correction films are different. A process of exposing the substrate using an exposure apparatus, and
Process of developing the substrate exposed in the process
Have,
The exposure apparatus,
An optical element having an optical surface on which a reflective film is installed, an optical element body having a non-optical surface opposite to the optical surface, and a plurality of correction films installed on the non-optical surface side for correcting the shape of the optical element body, and , The plurality of correction films, an optical element provided on the non-optical surface side with a region in which the correction film is not provided, and
Holding device for holding the optical element
Including a projection optical system comprising a,
Exposing the substrate through the projection optical system,
A gap between the first and second correction layers disposed outside the optical element body and adjacent to each other, and a third and fourth correction layers disposed inside the first and second correction layers and adjacent to each other. A method for manufacturing an article, characterized in that the intervals between the correction films are different.

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