Interferometric exposure apparatus and interferometric exposure method

Abstract

To provide an interference exposure apparatus capable of achieving a large slant angle. [Solution] An interference exposure apparatus according to one embodiment of the present invention comprises a prism that transmits a first beam and a second beam and has a first incident surface into which the first beam is incident, a second incident surface into which the second beam is incident, and an exit surface that emits the first beam and the second beam; a fluid that fills the space between the exit surface and the object to be irradiated and transmits the first beam and the second beam emitted from the exit surface; and an optical system that splits the light into a first beam and a second beam, causes the first beam to be incident on the first incident surface and the second beam to be incident on the second incident surface, wherein the optical axis of the first beam incident on the exposure surface from the fluid and the optical axis of the second beam incident on the exposure surface from the fluid are asymmetric with respect to the normal of the exposure surface in the irradiation region.

Description

[Technical Field]

[0001] The present invention relates to an interference exposure apparatus that performs exposure using interference fringes of two light beams. [Background technology]

[0002] Conventionally, two-beam interference exposure (hereinafter also simply called interference exposure) is known, which uses interference fringes of two light beams obtained by splitting coherent light such as laser light to expose an object to be irradiated (see, for example, Patent Documents 1 and 2). In two-beam interference exposure, by tilting the angle of incidence of the light beam to the object to be irradiated with respect to the normal direction of the surface of the object to be irradiated, a pattern inclined with respect to the normal direction can be formed on the surface of the workpiece. The inclination angle of this pattern with respect to the normal direction is called the "slant angle". [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-153446 [Patent Document 2] Japanese Patent Publication No. 2007-227637 [Overview of the project] [Problems that the invention aims to solve]

[0004] The objects being irradiated are generally photoresists or refractive index-modulated materials, and their refractive indices are around 1.5 to 1.8. Therefore, when a light beam enters the object from air (refractive index 1.0), it undergoes refraction, resulting in a smaller incident angle and a smaller slant angle, which presents a problem.

[0005] In view of the above circumstances, the object of the present invention is to provide an interference exposure apparatus capable of achieving a large slant angle. [Means for solving the problem]

[0006] To achieve the above objective, an interference exposure apparatus according to one embodiment of the present invention is an interference exposure apparatus that performs interference exposure on an object to be irradiated in the irradiation area by superimposing a first beam and a second beam obtained by splitting coherent light in an irradiation area on an exposure surface to cause interference, and comprises a prism, a fluid, and an optical system. The prism described above has a first incident surface through which the first beam and the second beam are transmitted, a second incident surface through which the second beam is incident, and an exit surface from which the first beam and the second beam are emitted. The fluid fills the space between the emission surface and the object to be irradiated, and transmits the first beam and the second beam emitted from the emission surface. The optical system splits the light into a first beam and a second beam, causes the first beam to be incident on a first incident surface, and causes the second beam to be incident on a second incident surface. The optical axes of the first beam incident on the exposure surface from the fluid and the optical axes of the second beam incident on the exposure surface from the fluid are asymmetric with respect to the normal to the exposure surface in the irradiation region.

[0007] In this configuration, the first and second beams penetrate the prism and fluid and enter the object to be irradiated. If the first and second beams enter the object from air, the difference in refractive index between the air and the object will cause refraction of the first and second beams, reducing the extension angle (slant angle) of the interference fringes produced by the interference of the first and second beams. In contrast, when the first and second beams enter the object to be irradiated by penetrating the prism and fluid, the refractive index of the prism is greater than that of air, so the refraction of the first and second beams entering the object is suppressed, and it is possible to prevent a decrease in the slant angle.

[0008] The prism may have a refractive index equal to or greater than that of the object being examined.

[0009] The first incident surface is configured such that the first beam, having passed through the first incident surface, proceeds toward the exit surface. The second incident surface may be configured such that the second beam, having passed through the second incident surface, proceeds toward the exit surface.

[0010] The optical system is configured such that the optical axis of the first beam incident on the first incident surface from the optical system and the optical axis of the second beam incident on the second incident surface from the optical system are asymmetric with respect to the normal. The first incident plane and the second incident plane may be symmetrical or asymmetrical with respect to the normal.

[0011] The optical system is configured such that the optical axis of the first beam incident on the incident surface from the optical system and the optical axis of the second beam incident on the incident surface from the optical system are symmetrical with respect to the normal. The first incident plane and the second incident plane may be asymmetrical with respect to the normal.

[0012] The prism may further include a first reflecting surface that reflects the first beam incident from the first incident surface toward the exit surface, and a second reflecting surface that reflects the second beam incident from the second incident surface toward the exit surface.

[0013] The prism further comprises a first reflective surface, a second reflective surface, and a third reflective surface. The first reflecting surface reflects the first beam incident from the first incident surface toward the third reflecting surface. The second reflecting surface reflects the second beam incident from the second incident surface toward the third reflecting surface. The third reflective surface may reflect the first beam incident from the first reflective surface and the second beam incident from the second reflective surface toward the exit surface.

[0014] The optical system is configured such that the optical axis of the first beam incident on the incident surface from the optical system and the optical axis of the second beam incident on the incident surface from the optical system are asymmetric with respect to the normal. The first reflective surface and the second reflective surface may be symmetrical or asymmetrical with respect to the normal.

[0015] The optical system is configured such that the optical axis of the first beam incident on the incident surface from the optical system and the optical axis of the second beam incident on the incident surface from the optical system are symmetrical with respect to the normal. The first reflective surface and the second reflective surface may be asymmetrical with respect to the normal.

[0016] The prism further has a first reflective surface, The first incident surface is configured such that the first beam, having passed through the first incident surface, proceeds toward the first reflecting surface. The second incident surface is configured such that the second beam, having passed through the second incident surface, proceeds toward the exit surface. The first reflecting surface may reflect the first beam, which has been incident from the first incident surface, toward the exit surface.

[0017] The optical system may be configured such that the optical axis of the first beam incident on the first incident surface from the optical system is perpendicular to the first incident surface, and the optical axis of the second beam incident on the second incident surface from the optical system is perpendicular to the second incident surface.

[0018] The prism may be arranged such that the emission surface is parallel to the exposure surface.

[0019] The prism has a hydrophilic emission surface. The fluid may be an aqueous liquid. [Effects of the Invention]

[0020] As described above, the present invention makes it possible to provide an interference exposure apparatus capable of achieving a large slant angle. The effects described herein are not necessarily limited, and any of the effects described in this disclosure may be provided. [Brief explanation of the drawing]

[0021] [Figure 1] This is a schematic diagram illustrating the overview of two-beam interference lithography. [Figure 2] This is a schematic diagram showing the interference fringes formed by the first and second beams in two-beam interference exposure. [Figure 3] This is a schematic diagram showing the first beam, the second beam, and the slant angle incident on the irradiation area in two-beam interference lithography. [Figure 4] This is a schematic diagram showing the first beam, the second beam, and the slant angle incident on the irradiation area in two-beam interference lithography. [Figure 5] This is a schematic diagram showing the first beam, the second beam, and the slant angle incident on the irradiation area in two-beam interference lithography. [Figure 6] This is a schematic diagram showing the periodic pattern formed on a photosensitive material by two-beam interference exposure. [Figure 7] This is a schematic diagram showing the first and second beams incident on the photosensitive material during two-beam interference exposure. [Figure 8] This is a schematic diagram showing the first and second beams incident on the photosensitive material during two-beam interference exposure. [Figure 9] This is a schematic diagram showing the first and second beams incident on the photosensitive material during two-beam interference exposure. [Figure 10] This is a schematic diagram showing an overview of the interference exposure apparatus according to this embodiment. [Figure 11] This is a schematic diagram illustrating interference exposure using the above-described interference exposure apparatus. [Figure 12] This is a schematic diagram showing the first and second beams that pass through the prism of the interference exposure apparatus described above. [Figure 13] This is a schematic diagram showing the first and second beams incident on the photosensitive material via the prism and fluid of the interference exposure apparatus described above. [Figure 14] This is a schematic diagram showing the incident angles of the first and second beams in the above interference exposure apparatus, assuming that prisms and fluid are not provided. [Figure 15] This is a schematic diagram showing the incident angles of the first and second beams in the above-described interference exposure apparatus. [Figure 16] This graph illustrates the range of slant angles and pitch widths (shaded areas) that can be exposed in the above interference exposure apparatus if prisms and fluid are not provided. [Figure 17] This graph illustrates the range of slant angles and pitch widths (shaded areas) that can be exposed using the above-mentioned interference exposure apparatus. [Figure 18] This is a schematic diagram showing the case where the first beam and the second beam are symmetrical with respect to the normal L in the above-described interference lithography apparatus. [Figure 19] This is a schematic diagram showing the configuration of the interference exposure apparatus described above. [Figure 20] This is a schematic diagram showing the detailed configuration of the interference exposure apparatus described above. [Figure 21] This is a schematic diagram showing other components of the prism in the interference exposure apparatus described above. [Figure 22] This is a schematic diagram showing other components of the prism in the interference exposure apparatus described above. [Figure 23] This is a schematic diagram showing other components of the prism in the interference exposure apparatus described above. [Figure 24] This is a schematic diagram showing other components of the prism in the interference exposure apparatus described above. [Modes for carrying out the invention]

[0022] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0023] [Overview of Two-Beam Interference Exposure] This document outlines the two-beam interference lithography method. Figure 1 is a schematic diagram illustrating the two-beam interference lithography method. In two-beam interference lithography, a first beam B1 and a second beam B2, obtained by splitting coherent light, are superimposed in an irradiation region R on the exposure surface E, and interference lithography is performed on the object W to be irradiated in the irradiation region R. The coherent emitted light that forms the basis of the first beam B1 and the second beam B2 is coherent light, and is typically laser light emitted from a laser light source. In each figure of this disclosure (except Figure 2), the optical axes of the first beam B1 and the second beam B2 are shown by lines. Furthermore, on the exposure surface E, directions that are orthogonal to each other are defined as the X direction and the Y direction, and the direction that is orthogonal to the XY plane is defined as the Z direction.

[0024] The irradiated object W is a substrate on which a photosensitive material M is provided on its surface. Any substrate can be used, such as a glass substrate, resin substrate, or semiconductor substrate. The photosensitive material M is a material whose properties change upon light irradiation, such as a photoresist or refractive index modulating material. It can be a material coated onto the substrate or a sheet-like material bonded to the substrate. The type of substrate and photosensitive material is not limited.

[0025] In Figure 1, the normal L of the exposure surface E in the irradiation region R is shown. Hereafter, as shown in the same figure, the angle between the optical axis of the first beam B1 and the normal L is defined as the angle of incidence θ1, and the angle between the optical axis of the second beam B2 and the normal L is defined as the angle of incidence θ2. In the following, for the angles of incidence θ1 and θ2, the case where the optical axis of the first beam B1 or the second beam B2 coincides with the normal L is defined as 0°, and the direction counterclockwise with respect to the normal L is defined as the positive direction. For example, in Figure 1, the angle of incidence θ1 is a positive value, and the angle of incidence θ2 is a negative value.

[0026] In two-beam interference lithography, a slant angle can be set by the angle of incidence of the first beam B1 and the second beam B2 to the exposure surface E. Figure 2 is a schematic diagram showing the interference fringes F formed by the first beam B1 and the second beam B2. As described above, the first beam B1 and the second beam B2 are generated by splitting coherent light. In the region where these two beams overlap, interference fringes F are generated, as shown in Figure 2, in which regions where each beam reinforces (black region) and regions where they cancel each other out (white region) are alternately formed. Hereinafter, the extension direction of the interference fringes F will be defined as the slant direction D, and the angle between the slant direction D and the normal L (Z direction) will be defined as the slant angle α. The period of the interference fringes F will be defined as the pitch width p.

[0027] Figures 3 to 5 are schematic diagrams showing the first beam B1, the second beam B2, and the slant angle incident on the irradiation region R. In Figures 3 to 5, the incident angles of the first beam B1 and the second beam B2 with respect to the exposure surface E are different. As shown in Figures 3 to 5, the slant angle α increases as the sum of the incident angles θ1 and θ2 increases. Specifically, the slant angle α is expressed using the following equation (1).

[0028]

number

[0029] From equation (1), the slant angle α is the angle obtained by bisecting the sum of the incident angles (θ1 + θ2), and is the angle that the bisectors of the optical axes of the first beam B1 and the second beam at the exposure surface E make with the normal L. For example, in the example in Figure 3, the incident angle θ1 is 30° and the incident angle θ2 is -30°, so the slant angle α is 0°. In the example in Figure 4, the incident angle θ1 is 20° and the incident angle θ2 is -40°, so the slant angle α is -10°. In the example in Figure 5, the incident angle θ1 is -15° and the incident angle θ2 is -75°, so the slant angle α is -45°.

[0030] Furthermore, if the wavelengths of the first beam B1 and the second beam B2 are λ, and the refractive index of the medium (e.g., photosensitive material M) on which the interference fringes F are formed is n, then the pitch width p of the interference fringes F can be expressed using the following equation (2).

[0031]

number

[0032] From equation (2), the pitch width p changes according to the angle (|θ1-θ2|) between the optical axes of the first beam B1 and the second beam. In this way, the slant angle α and the pitch width p can be adjusted by appropriately setting the incident angles θ1 and θ2 of the first beam B1 and the second beam B2.

[0033] In interference exposure, the photosensitive material provided on the surface of the object to be irradiated W is exposed by such interference fringes F. Figure 6 is a schematic diagram of the periodic pattern formed on the photosensitive material M by interference exposure. As shown in the figure, a periodic pattern similar to the interference fringes F is formed on the photosensitive material, and the slant angle α and pitch width p are reflected in the shape of the periodic pattern.

[0034] Here, when creating a slant angle α by two-beam interference exposure, the refractive index of the photosensitive material M (see Figure 1) becomes an issue. Figures 7 to 9 are schematic diagrams showing the first beam B1 and the second beam B2 incident on the photosensitive material M. Since the refractive index of the photosensitive material M is greater than that of air (1.0), the first beam B1 and the second beam B2 incident on the photosensitive material M are refracted as shown in Figures 7 to 9. As a result, the angle of incidence of the first beam B1 and the second beam B2 with respect to the exposure surface E becomes smaller, and the slant angle α also becomes smaller. Note that in Figures 7 to 9, the refractive index of the photosensitive material M is assumed to be 1.5.

[0035] For example, in the example in Figure 7, the incident angle θ1 is 30° and the incident angle θ2 is -30°, but the incident angle θ1' in the photosensitive material M (refractive index 1.5) is 20° and the incident angle θ2' is -20°, so the slant angle α is 0°. In the example in Figure 8, the incident angle θ1 is 20° and the incident angle θ2 is -40°, but the incident angle θ1' in the photosensitive material M is 15° and the incident angle θ2' is -25°, so the slant angle α is -5°. In the example in Figure 9, the incident angle θ1 is -15° and the incident angle θ2 is -75°, but the incident angle θ1' in the photosensitive material M is 0° and the incident angle θ2' is -40°, so the slant angle α is -20°.

[0036] Comparing Figure 4 and Figure 8, the slant angle α decreases from -10° to -5°, and comparing Figure 5 and Figure 9, the slant angle α decreases from -45° to -20°. This decrease in the slant angle α is caused by refraction in the photosensitive material M of the first beam B1 and the second beam B2, and as a result, the slant angle α in the periodic pattern shown in Figure 6 is also limited. In contrast, the interference exposure apparatus according to this embodiment can suppress the decrease in the slant angle α caused by refraction in the photosensitive material M, as shown below.

[0037] [Schematic configuration of an interferometry exposure system] Figure 10 is a schematic diagram showing an overview of the interference exposure apparatus 100 according to this embodiment. As shown in the figure, the interference exposure apparatus 100 comprises an optical system 101, a prism 102, and a fluid 103, and performs interference exposure on the object to be irradiated W. As described above, the object to be irradiated W is a substrate on which a photosensitive material M is arranged on the surface. Figure 11 is a schematic diagram showing interference exposure by the interference exposure apparatus 100. As shown in the figure, the interference exposure apparatus 100 superimposes the first beam B1 and the second beam B2 in the irradiation area R on the exposure surface E, and performs interference exposure on the object to be irradiated W in the irradiation area R.

[0038] The exposure surface E is a virtual plane on which interference exposure takes place. The exposure surface E is determined by the support mechanism for the object to be irradiated W provided by the interference exposure apparatus 100, and is a plane parallel to the stage surface when the object to be irradiated W is placed on a stage. In addition, when the object to be irradiated W is supported by a support structure such as a clamp, the exposure surface E is a plane parallel to the surface of the object to be irradiated W. The object to be irradiated W is positioned so that its surface coincides with the exposure surface E. The irradiation region R is the region on the surface of the object to be irradiated W where both the first beam B1 and the second beam B2 irradiate, that is, the region where interference exposure occurs on the exposure surface E. In this disclosure, the term "beam" can be read as "light wave" or "light beam."

[0039] In the following, directions perpendicular to each other on the exposure surface E are defined as the X and Y directions, and the direction perpendicular to the XY plane is defined as the Z direction. Figure 11 shows the normal L of the exposure surface E in the irradiation region R. The normal L is a straight line parallel to the Z direction.

[0040] The components of the interference exposure apparatus 100 will now be described. The optical system 101 splits coherent light emitted from a light source (not shown) into a first beam B1 and a second beam B2, and causes the first beam B1 and the second beam B2 to be incident on the prism 102. As shown in Figure 11, the angle between the optical axis of the first beam B1 incident on the prism 102 from the optical system 101 and the normal L is defined as the incident angle θ1a, and the angle between the optical axis of the second beam B2 incident on the prism 102 from the optical system 101 and the normal L is defined as the incident angle θ2a.

[0041] For the incident angles θ1a and θ2a, the case where the optical axis of the first beam B1 or the second beam B2 coincides with the normal L is defined as 0°, and the direction counterclockwise with respect to the normal L is defined as the positive direction. For example, in Figure 11, both the incident angles θ1a and θ2a are negative values. The detailed configuration of the optical system 101 will be described later.

[0042] The prism 102 transmits the first beam B1 and the second beam B2 incident from the optical system 101. The prism 102 is made of a material that is transparent to the first beam B1 and the second beam B2. Also, the prism 102 is preferably made of a material having a refractive index equal to or higher than that of the photosensitive material M. "Equal to or higher than the refractive index of the photosensitive material M" means 85% or more of the refractive index of the photosensitive material M. When the refractive index of the photosensitive material M is 1.50, the refractive index equal to or higher than that is 1.28 or more. Specifically, when the photosensitive material M is a photoresist (refractive index 1.5), synthetic quartz (refractive index 1.40 to 1.55) or calcium fluoride (refractive index 1.33 to 1.51) can be used as the material of the prism 102. [[ID=...]]

[0043] FIG. 12 is a schematic diagram showing the first beam B1 and the second beam B2 passing through the prism 102. As shown in the figure, the prism 102 has a first surface 111, a second surface 112, and a third surface 113. In the prism 102, the surface on which the first beam B1 is incident is the first incident surface S E , N , N , E ,

[0044] , E , , N , <00000I2>, N , N , E , , 1, the surface on which the second beam B2 is incident is the second incident surface S N 2, and the surface from which the first beam B1 and the second beam B2 are emitted is the emission surface S<OO00003>Then, the first surface 111 is the first incident surface S N 1, the second surface 112 is the second incident surface S N 2, and the third surface 113 is the emission surface S E is.

[0044] The first incident surface S N 1 is configured such that the first beam B1 passing through the first incident surface S N 1 travels toward the emission surface S E . Specifically, the normal line of the first incident surface S N 1 intersects the emission surface S E . The second incident surface S N 2 is configured such that the second beam B2 passing through the second incident surface S N 2 travels toward the emission surface S E . Specifically, the normal line of the second incident surface S N 2 intersects the emission surface S E .

[0045] 1st entrance plane S N The incidence angle of the first beam B1 relative to 1 is given by the first incidence plane S N An angle perpendicular to 1 is preferable. Also, the second incident plane S N The incidence angle of the first beam B2 relative to 2 is given by the second incidence plane S N An angle perpendicular to 2 is preferable. Furthermore, the exit surface S E Preferably, it is parallel to the exposure surface E.

[0046] As shown in Figure 12, the first incident plane S N The angle between the optical axis of the first beam B1 incident from 1 and the normal L is defined as the angle of incidence θ1b, and the second incidence plane S N Let the angle between the optical axis of the second beam B2, which is incident from 2, and the normal L be the incident angle θ2b. The first incident plane S of the first beam B1. N By making the incident angle perpendicular to 1, the incident angle θ1b can be made the same as the incident angle θ1a. Also, the second incident surface S of the second beam B2 N By making the angle of incidence perpendicular to 1, the angle of incidence θ2b can be made the same as the angle of incidence θ2a.

[0047] The fluid 103 is directed to the exit surface S E The space between the object to be irradiated W and the emission surface S E The fluid 103 penetrates the first beam B1 and the second beam B2 emitted from the exit surface S. The fluid 103 is permeable to the first beam B1 and the second beam B2 and is fluid, and exit surface S E Any substance that can completely fill the space between the irradiated object W and the fluid 103 is acceptable, and may include liquids or gels. The refractive index of the fluid 103 is the emission surface S E Any fluid that does not undergo total internal reflection at the interface between the fluid and fluid 103 is acceptable. Specifically, pure water (refractive index 1.33) can be used as fluid 103, but other fluids can also be used.

[0048] With respect to holding the fluid 103, the prism 102 has at least an exit surface S EIt is preferable that the fluid has hydrophilic properties. By making the fluid 103 an aqueous liquid (including pure water or aqueous solution), the fluid 103 can be ejected to the surface S E Even if the object to be irradiated W moves relative to the prism 102, the emission surface S E The fluid 103 can be held between the irradiated object W and the fluid 103.

[0049] Figure 13 is a schematic diagram showing the first beam B1 and the second beam B2 incident on the photosensitive material M via the prism 102 and the fluid 103. As shown in the figure, the exit surface S E The angle between the optical axis of the first beam B1, which is emitted from the source, passes through the fluid 103, and is incident on the photosensitive material M, and the normal L is defined as the angle of incidence θ1c, and the emission surface S E The angle between the optical axis of the second beam B2, which is emitted from the prism 102, passes through the fluid 103, and is incident on the photosensitive material M, and the normal L is defined as the angle of incidence θ2c. If the refractive index of the prism 102 is the same as that of the photosensitive material M, the angle of incidence θ1c is the same as the angle of incidence θ1b, and the angle of incidence θ2c is the same as the angle of incidence θ2b.

[0050] Furthermore, if the refractive index of the fluid 103 is equivalent to that of the photosensitive material M and the prism 102, the emission surface S E Since no refraction occurs at the interface between fluid 103 and the photosensitive material M, the incident angle θ1c is equivalent to the incident angle θ1b, and the incident angle θ2c is equivalent to the incident angle θ2b. Furthermore, even if the refractive index of fluid 103 is smaller than that of the photosensitive material M and the prism 102, Snell's law cancels out the refraction at both interfaces, so in this case as well, the incident angle θ1c is equivalent to the incident angle θ1b, and the incident angle θ2c is equivalent to the incident angle θ2b.

[0051] As a result, the incident angle θ1c becomes equivalent to the incident angle θ1a, and the incident angle θ2c becomes equivalent to the incident angle θ2a. Therefore, in the interference exposure apparatus 100 according to this embodiment, refraction (see Figures 7 to 9) when the first beam B1 and the second beam B2 are incident on the photosensitive material M is suppressed, and it is possible to prevent a decrease in the slant angle α due to this refraction.

[0052] As a specific example, Figure 14 is a schematic diagram showing the incident angles of the first beam B1 and the second beam B2 in the interference exposure apparatus 100 when the prism 102 and fluid 103 are not provided. When the incident angle θ1 is -20° and the incident angle θ2 is -60°, the incident angle θ1' in the photosensitive material M (refractive index 1.5) is 0°, the incident angle θ2' is -30°, and the slant angle α is -15°.

[0053] On the other hand, Figure 15 is a schematic diagram showing the incident angles of the first beam B1 and the second beam B2 in the interference exposure apparatus 100. When the incident angle θ1a is -30° and the incident angle θ2a is -60°, the incident angle θ1c in the photosensitive material M (refractive index 1.5) remains at -30°, and the incident angle θ2c remains at -60°, resulting in a slant angle α of -45°. In this way, the slant angle α can be increased by using the prism 102 and the fluid 103.

[0054] Figure 16 shows, for comparison, the range of slant angle α and pitch width p (shaded area) that can be exposed in the interference exposure apparatus 100 if the prism 102 and fluid 103 are not provided. On the other hand, Figure 17 shows the range of slant angle α and pitch width p (shaded area) that can be exposed in the interference exposure apparatus 100 equipped with the same optical system 101 as the interference exposure apparatus in Figure 16, and further equipped with the prism 102 and fluid 103. By comparing Figure 16 and Figure 17, it can be said that by using the interference exposure apparatus 100, it is possible to sufficiently widen the range of slant angle α that can be exposed.

[0055] Note that the first incident surface S of the first beam B1 N The angle of incidence relative to 1 and the second incident plane S of the second beam B2. N If the angle of incidence to 2 is not perpendicular, or if the refractive index of prism 102 is smaller than the refractive index of photosensitive material M, the angle of incidence θ1c may be smaller than the angle of incidence θ1a, and the angle of incidence θ2c may be smaller than the angle of incidence θ2a. Nevertheless, by using prism 102 and fluid 103, it is possible to suppress the decrease in the slant angle α compared to when they are not used.

[0056] [Regarding optical axis asymmetry] In order to form a slant (make the slant angle greater than 0°) in the interference exposure apparatus 100, as shown in Figure 13, it is necessary to make the optical axes of the first beam B1 incident on the exposure surface E from the fluid 103 and the optical axes of the second beam B2 incident on the exposure surface E from the fluid 103 asymmetric with respect to the normal L (hereinafter referred to as "optical axis asymmetry"). Asymmetric with respect to the normal L means that even if one of the optical axes of the first beam B1 and the second beam B2 incident on the exposure surface E is rotated 180° with respect to the normal L, it will not overlap with the optical axis of the other, and in the relationship between the incident angles θ1c and θ2c, it means that the sum of the incident angles θ1c and θ2c is not 0.

[0057] In the interference exposure apparatus 100, the optical axis of the first beam B1 incident on the prism 102 from the optical system 101 and the optical axis of the second beam B2 incident on the prism 102 from the optical system 101 are symmetric with respect to the normal L, that is, the sum of the incident angles θ1a and θ2a can be 0. Figure 18 shows an example of this, where the sum of the incident angles θ1a and θ2a is 0. In this case, as shown in the figure, the first incident surface S of the prism 102 N 1 and the second incident plane S N By making point 2 asymmetric with respect to the normal vector L, optical axis asymmetry can be achieved, and a slant can be formed.

[0058] Furthermore, in the interference exposure apparatus 100, as shown in Figure 13, the optical axis of the first beam B1 incident on the prism 102 from the optical system 101 and the optical axis of the second beam B2 incident on the prism 102 from the optical system 101 can be asymmetric with respect to the normal L, that is, the sum of the incident angles θ1a and θ2a is not zero. In this case, the first incident surface S of the prism 102 N 1 and the second incident plane S N Even if 2 is symmetric with respect to the normal L, or the first incident plane S of prism 102 N 1 and the second incident plane S N By making 2 asymmetric with respect to the normal L, optical axis asymmetry can be achieved, and a slant can be formed.

[0059] Note that the first incident surface S N 1 and the second incident plane S N2 is asymmetric with respect to the normal L if the first incident plane S N 1 and the second incident plane S N This means that even if one of the two is rotated 180° with respect to the normal L, it will not overlap with the other. Also, the first incident plane S N 1 and the second incident plane S N 2 is symmetric with respect to the normal L if it is the first incident plane S N 1 and the second incident plane S N This means that if one of the two points is rotated 180° with respect to the normal vector L, it will overlap with the other point.

[0060] As described above, in the interference exposure apparatus 100, optical axis asymmetry may be achieved by the optical system 101, or by the prism 102. Furthermore, it is also possible to achieve optical axis asymmetry by both the optical system 101 and the prism 102.

[0061] [Configuration of an Interferometry Exposure System] Figure 19 is a schematic diagram showing the configuration of the interference exposure apparatus 100. As described above, the interference exposure apparatus 100 includes an optical system 101, a prism 102, and a fluid 103. As shown in Figure 19, the optical system 101 includes a laser light source 20, a relay mirror 21, a demultiplexer 22, two relay drive mirrors 23a and 23b, and two irradiation drive mirrors 24a and 24b.

[0062] The laser light source 20 emits a beam B0, which is a laser with wavelength λ. The type of laser light source 20 and the wavelength λ of beam B0 are not limited. In this embodiment, beam B0 is an example of coherent emitted light. The beam B0 emitted from the laser light source 20 is appropriately reflected by the relay mirror 21 and incident on the demultiplexer 22.

[0063] The demultiplexing element 22 splits beam B0 into a first beam B1 and a second beam B2. A beam splitter or diffraction grating can be used as the demultiplexing element 22. Figure 19 illustrates that beam B0, incident on the demultiplexing element 22 from above, is split into a first beam B1 directed to the left and a second beam B2 directed to the right. In reality, the first beam B1 and the second beam B2 are not necessarily split in opposite directions, so the exit direction of each beam is adjusted as appropriate using mirrors or the like.

[0064] The relay drive mirrors 23a and 23b are mirrors that are driven to control the reflection direction of the incident beam. The relay drive mirror 23a reflects the first beam B1 emitted from the demultiplexer 22 toward the irradiation drive mirror 24a. The relay drive mirror 23b reflects the second beam B2 emitted from the demultiplexer 22 toward the irradiation drive mirror 24b.

[0065] The illumination drive mirror 24a moves along the first drive shaft 25a and rotates relative to the first drive shaft 25a, and illuminates the first incident surface S of the prism 102. N The first beam B1 is reflected toward 1. The illumination drive mirror 24b moves along the second drive axis 25b and rotates relative to the second drive axis 25b, and the second incident surface S of the prism 102 N The second beam B2 is reflected towards point 2.

[0066] Here, the drive shafts (first drive shaft 25a and second drive shaft 25b) refer to axes that define the movement path of, for example, the mirrors (illumination drive mirror 24a and illumination drive mirror 24b). For example, suppose a mirror is mounted on a base that moves along a guide member. In this case, since the mirror moves along the guide member, the guide member can be considered as the drive shaft of the mirror. The mechanism for moving the mirror is not limited.

[0067] Furthermore, the rotation of the mirror relative to the drive shaft includes rotation around the Y-axis (rotational drive). It may also include rotation that tilts relative to the XZ plane (tilt drive). The rotational drive controls the reflection direction of the beam along the XZ plane, and the tilt drive controls the tilt of the reflection direction of the beam relative to the XZ plane. The mechanism for rotating the mirror is not limited.

[0068] The first drive shaft 25a and the second drive shaft 25b are positioned along a common reference plane 26 that is perpendicular to the object to be irradiated W. For example, the surface of the optical table on which the optical system 101 is provided is the reference plane 26. As a result, for example, the first drive shaft 25a and the second drive shaft 25b become axes aligned with the incident planes (XZ planes) of the first beam B1 and the second beam B2. As a result, it is possible to sufficiently avoid situations in which the incident axes of each beam shift in the Y direction even if, for example, the irradiation drive mirror 24a or the irradiation drive mirror 24b moves, thereby improving the stability of interference exposure.

[0069] In Figure 19, the first drive shaft 25a and the second drive shaft 25b are shown as straight shafts, but other shafts, such as arc-shaped shafts, may also be used. Furthermore, the first drive shaft 25a and the second drive shaft 25b do not need to be individually configured shafts, but can be configured as a common shaft.

[0070] Furthermore, as shown in Figure 19, the interference exposure apparatus 100 includes a sensor unit 12 and a control unit 13. The sensor unit 12 is a sensor for detecting the incident angle θ1c of the first beam B1 and the incident angle θ2c of the second beam B2 (see Figure 13) with respect to the irradiated object W. The sensor unit 12 is composed of a measuring instrument that measures the slant angle α, pitch width p, and interference fringe direction of the interference fringes F produced by the first beam B1 and the second beam B2, and is used by moving it appropriately within the irradiation area R. The incident angles θ1c and θ2c are detected from these measurement results.

[0071] The control unit 13 is a control device that controls the operation of the entire interference exposure apparatus 100, and has the necessary hardware configuration for a computer, such as a CPU (Central Processing Unit) and memory. The control unit 13 controls the incident angles θ1a and θ2a (see Figure 13) of the first beam B1 and the second beam B2 to the object W, according to the input values ​​relating to the slant angle α and pitch width p of the interference fringes F formed on the object W.

[0072] Thus, in the interference exposure apparatus 100, the optical arrangement of the optical system 101 (for example, the position and rotation angle of the illumination drive mirrors 24a and 24b) is automatically controlled to achieve a desired slant angle α and pitch width p. This makes it possible to achieve a wide range of slant angles α and any pitch width p.

[0073] Furthermore, the control unit 13 controls the optical system 10 based on the detection results of the sensor unit 12. This enables feedback control, such as adjusting the position and rotation angle of the illumination drive mirrors 24a and 24b according to the actual state of the interference fringes F, thereby enabling the precise realization of the desired interference fringes F.

[0074] [Specific Equipment Configuration of Interferometry Exposure System] Figure 20 is a schematic front view showing the specific configuration of the interference exposure apparatus 100. In the following description, parts common to the configuration of the optical system 101, as explained with reference to Figure 19, will be described using the same reference numerals.

[0075] As shown in Figure 20, in this embodiment, the first drive shaft 25a and the second drive shaft 25b are each arc axes that surround the illumination area R. The arc axes are arranged, for example, so as to be centered on the illumination area R. By using arc axes, the positions of the illumination drive mirrors 24a and 24b in the X and Z directions can be easily changed. This makes it possible to sufficiently widen the control range of the incident angles θ1a and θ2a. Furthermore, it becomes possible to configure the optical system 101 in a compact manner.

[0076] Here, a common arc-shaped shaft (an arc-shaped drive shaft 35, described later) is used as the first drive shaft 25a and the second drive shaft 25b. This simplifies the device configuration and reduces manufacturing and maintenance costs. Alternatively, the first drive shaft 25a and the second drive shaft 25b may be provided individually as concentric arc-shaped shafts. In this case, for example, the second drive shaft 25b may be positioned outside or inside the first drive shaft 25a.

[0077] The interference exposure apparatus 100 includes an optical system 101, a prism 102, and a fluid 103, as well as a frame section 14, a stage mechanism 11, a sensor section 12, and a control section 13 (not shown).

[0078] The frame section 14 is the frame of the interference exposure apparatus 100 and supports the optical system 101 and the stage mechanism 11. The frame section 14 includes a stage support base 15, an optical table support frame 16, a light source support base 17, and a connecting frame 18.

[0079] The stage support base 15 is a plate-shaped member that supports the stage mechanism 11. The stage support base 15 may have, for example, legs with a suspension function. The optical table support frame 16 is provided on the upper surface of the stage support base 15 and supports the optical table 30 of the optical system 10, which will be described later. The light source support base 17 is a plate-shaped member that supports the laser light source 20, etc., and is positioned above the optical table 30. The connecting frame 18 connects the optical table support frame 16 and the light source support base 17 and is a frame that supports the light source support base 17. Note that the connecting frame 18 provided on the front is not shown in Figure 20.

[0080] The optical system 10 includes a laser light source 20, an exposure shutter T, four intermediate mirrors 21a to 21d, a demultiplexer 22, intermediate drive mirrors 23a and 23b, and irradiation drive mirrors 24a and 24b. The optical system 10 also includes an optical table 30, a linear drive shaft 31, three linear motion parts 32a to 32c, an arc drive shaft 35, and arm parts 36a and 36b. These components constitute the optical system 10, which comprises an output optical system 37, a linear bench optical system 38, and an arc arm optical system 39.

[0081] The emission optical system 37 is an optical system that emits beam B0, which is the source of the first beam B1 and the second beam B2, toward the linear bench optical system 38. The emission optical system 37 is configured on the light source support base 17 and includes a laser light source 20, an exposure shutter, and relay mirrors 21a and 21b.

[0082] The laser light source 20 is provided on the upper surface of the light source support base 17 and emits laser light (beam B0) of wavelength λ toward the relay mirror 21a. The exposure shutter T is a shutter for blocking the beam B0 and is provided between the laser light source 20 and the relay mirror 21a. A rotary shutter is used here, but other types of shutters may be used. The relay mirror 21a is provided on the upper surface of the light source support base 17 and reflects the beam B0 toward the relay mirror 21b. The relay mirror 21b is provided on the lower surface of the light source support base 17 and reflects the beam B0 toward the relay mirror 21c.

[0083] In the example shown in Figure 20, the beam B0 emitted from the laser light source 20 is reflected on the upper surface of the light source support base 17 by relay mirrors 21a and 21b located to the right of the light source support base 17 so that it travels to the left on the lower surface of the light source support base 17.

[0084] Next, the parts of the optical system 10 provided on the optical table 30 (linear bench optical system 38, arc arm optical system 39) will be described. The optical table 30 is a rectangular plate member as a whole. The rear surface of the optical table 30 is connected to the optical table support frame 16 and is supported along the XZ plane such that a pair of edges (in this case, the long sides) are parallel to the X direction. The front surface of the optical table 30 is the reference plane 26, as explained with reference to Figure 19. The optical paths of the first beam B1 and the second beam B2 are basically set to be parallel to the reference plane 26.

[0085] The linear bench optical system 38 generates a first beam B1 and a second beam B2 and supplies each beam toward the arc arm optical system 39. The linear bench optical system 38 has relay mirrors 21c and 21d, a demultiplexer 22, relay drive mirrors 23a and 23b, three linear motion units 32a to 32c, and a linear drive axis 31, and is configured along the upper edge of the optical table 30.

[0086] The linear drive shaft 31 is a linear drive shaft provided along the X direction on the upper edge of the optical table 30. The linear motion sections 32a to 32c are bases that can move along the linear drive shaft 31. Optical components are arranged on the surfaces of each linear motion section 32a to 32c that face forward. In this embodiment, the linear drive shaft 31 corresponds to a linear shaft different from the first drive shaft and the second drive shaft.

[0087] For example, a rack gear with linearly shaped tooth grooves is used for the linear drive shaft 31. In this case, each linear motion unit 32a to 32c has a pinion gear that meshes with the rack gear, and by rotating the pinion gear, each moves independently along the linear drive shaft 31. The configuration of the linear motion mechanism is not limited, and a rail without screw grooves or the like may be used as the linear drive shaft 31. Furthermore, any mechanism that can move independently along the linear drive shaft 31 can be used for the linear motion units 32a to 32c.

[0088] As shown in Figure 20, a relay mirror 21c, a demultiplexer 22, and a relay mirror 21d are arranged in order from top to bottom on the front of the central linear motion unit 32c. The relay mirror 21c reflects the beam B0 incident from the relay mirror 21b toward the demultiplexer 22 located below it.

[0089] The demultiplexing element 22 splits beam B0 into a first beam B1 and a second beam B2. The demultiplexing element 22 is also mounted on the linear motion unit 32c and moves along the linear drive shaft 31. In this case, a beam splitter is used as the demultiplexing element 22, but a diffraction grating or the like can be used instead. The beam splitter may be an intensity-type beam splitter or a deflection-type beam splitter. In this case, a planar plate type beam splitter is used, but a prism type may also be used.

[0090] In the example shown in Figure 20, the demultiplexer 22 (beam splitter) is positioned at a 45° tilt with respect to the ZY plane, with its upper end tilted to the right. As a result, of the beam B0 incident on the demultiplexer 22, a portion is reflected by the demultiplexer 22 and becomes a first beam B1 propagating to the left, while another portion passes through the demultiplexer 22 and becomes a second beam B2 propagating downward. The second beam B2 is reflected to the right by a relay mirror 21d positioned directly below the demultiplexer 22.

[0091] The relay drive mirror 23a moves along the linear drive axis 31 and rotates relative to the linear drive axis 31, reflecting the first beam B1 toward the illumination drive mirror 24a. The relay drive mirror 23a is rotatably mounted on the front of the left linear motion section 32a of the demultiplexing element 22. The relay drive mirror 23b also moves along the linear drive axis 31 and rotates relative to the linear drive axis 31, reflecting the second beam B2 toward the illumination drive mirror 24b. The relay drive mirror 23b is rotatably mounted on the front of the right linear motion section 32b of the demultiplexing element 22.

[0092] Thus, in the linear bench optical system 38, the relay drive mirrors 23a and 23b and the demultiplexer element 22 positioned between them can move independently of each other along a single linear drive axis 31. In the linear motion section 32c, the relay mirrors 21c and 21d also move together with the demultiplexer element 22, so that the incident direction of beam B0 on ​​the demultiplexer element 22 and the exit directions of the first beam B1 and the second beam B2 can be maintained. This makes it possible to easily move the demultiplexer element 22 without affecting other optical systems. Furthermore, because the demultiplexer element 22 is movable, the range of movement of the relay drive mirrors 23a and 23b can be expanded, which improves the degree of freedom of the optical path of each beam relative to the arc arm optical system 39.

[0093] The arc-arm optical system 39 is an optical system that illuminates the prism 102 with the first beam B1 and the second beam B2. The arc-arm optical system 39 has illumination drive mirrors 24a and 24b, arm sections 36a and 36b, and an arc drive shaft 35, and is configured along the front surface (reference plane 26) of the optical table 30.

[0094] The arc drive shaft 35 is an arc-shaped drive shaft provided along the reference plane 26 (XZ plane) of the optical table 30. The arm portions 36a and 36b are bases that can move along the arc drive shaft 35.

[0095] For example, a rack gear with teeth formed in an arc shape is used for the arc drive shaft 35. In this case, each arm portion 36a and 36b has a pinion gear that meshes with the rack gear, and by rotating the pinion gear, each moves independently along the arc drive shaft 35. The configuration of the arc drive mechanism is not limited, and a rail without screw grooves or the like may be used as the arc drive shaft 35. Furthermore, any mechanism that allows the arms 36a and 36b to move independently along the arc drive shaft 35 can be used for their movement.

[0096] The arc drive axis 35 is typically positioned around the irradiation area R. For example, when viewed in the XZ plane, the arc drive axis 35 is positioned on the optical table 30 such that its center coincides with the center point of the irradiation area R (such as the intersection point of the first beam B1 and the second beam B2). This makes it easy to associate the respective incident angles θ1a and θ2a of the first beam B1 and the second beam B2 with the positions on the arc drive axis 35 of the irradiation drive mirrors 24a and 24b.

[0097] The illumination drive mirrors 24a and 24b reflect the first beam B1 and the second beam B2 toward the illumination area R. Irradiation drive mirror 24a is rotatably mounted on the front of the right arm portion 36a, and illumination drive mirror 24b is rotatably mounted on the front of the left arm portion 36b. As a result, illumination drive mirrors 24a and 24b each move independently along the arc drive axis 35 and rotate relative to the arc drive axis 35.

[0098] Arm sections 36a and 36b are longitudinal bases on which optical components are mounted. In addition to the illumination drive mirrors 24a and 24b, adjustment optical systems 40a and 40b are provided on arm sections 36a and 36b, respectively. Adjustment optical system 40a is an optical system that adjusts the first beam B1 reflected by the illumination drive mirror 24a, and adjustment optical system 40b is an optical system that adjusts the second beam B2 reflected by the illumination drive mirror 24b. For example, the adjustment optical systems 40a and 40b are arranged along the longitudinal direction of arm sections 36a and 36b. Therefore, the longitudinal direction of each arm section 36a and 36b is the direction of the incident axis of the first beam B1 and the second beam B2.

[0099] As shown in Figure 20, the arm portion 36a moves along the arc drive axis 35 so that the adjustment optical system 40a faces the irradiation area R. Similarly, the arm portion 36b moves along the arc drive axis 35 so that the adjustment optical system 40b faces the irradiation area R. For example, the arms 36a and 36b are moved so that their longitudinal direction coincides with the radial direction (direction toward the center) of the arc drive axis 35. This is achieved, for example, by using a mechanism to maintain the attitude of the arms 36a and 36b relative to the arc drive axis 35, or by using guides formed concentrically with the arc drive axis 35. As a result, regardless of the position of the arms 36a and 36b (irradiation drive mirrors 24a and 24b) on the arc drive axis 35, the incident axes of the first beam B1 and the second beam B2 are directed toward the irradiation area R.

[0100] The specific configuration of the interference exposure apparatus 100 described above is merely an example and is not limited to those described above. For example, the optical system 101 splits the light emitted from the laser light source 20 (beam B0) into a first beam B1 and a second beam B2, and the first beam B1 is directed to the first incident surface S of the prism 102. N The second beam Bb is incident on 1, and then directed onto the second incident surface S of prism 102. N Any device that is incident on point 2 is acceptable, and configurations other than those described above are also possible.

[0101] [Regarding other prism configurations] The prism 102 of the interference exposure apparatus 100 can also have the following configuration. Figures 21 to 24 are schematic diagrams showing other configurations of the prism 102. As shown in Figure 21, the prism 102 may have a first surface 121, a second surface 122, a third surface 123, and a fourth surface 124. The first surface 121 is the first incident surface S into which the first beam B1 is incident. N The second incident surface S into which beams 1 and 2 B2 are incident. N It serves two purposes. The second surface 122 is the emission surface S from which the first beam B1 and the second beam B2 are emitted. E That is the case.

[0102] The third surface 123 is the first incident surface S N The first beam B1, which was injected from point 1, exits from surface S. EThe first reflective surface S that reflects toward R The answer is 1. The fourth surface 124 is the second incident surface S N The second beam B2, which was injected from 2, exits from surface S. E The second reflective surface S reflects toward R The answer is 2. Reflective coatings are provided on the third surface 123 and the fourth surface 124 to provide light reflectivity.

[0103] 1st entrance plane S N The incidence angle of the first beam B1 relative to 1 is given by the first incidence plane S N An angle perpendicular to 1 is preferable. Also, the second incident plane S N The incidence angle of the first beam B2 relative to 2 is given by the second incidence plane S N An angle perpendicular to 2 is preferable. Furthermore, the exit surface S E Preferably, it is parallel to the exposure surface E.

[0104] In this configuration, as shown in Figure 21, the first beam B1 is connected to the first incident surface S N When light enters prism 102 from point 1, the first reflective surface S R Reflected by 1, exit surface S E It is emitted from. Furthermore, the first beam B1 passes through the fluid 103 and is incident on the photosensitive material M. The second beam B2 is incident on the second incident surface S N When light enters prism 102 from point 2, it reaches the second reflection surface S. R Reflected by 2, exit surface S E It is emitted from there. Furthermore, the second beam B2 passes through the fluid 103 and is incident on the photosensitive material M.

[0105] In this configuration as well, the prism 102 and fluid 103 prevent refraction of the first beam B1 and the second beam B2, thereby suppressing the decrease in the slant angle α. In particular, by utilizing reflection from the third surface 123 and the fourth surface 124, which are the sides of the prism 102, the number of reflections can be reduced and wavefront fluctuations can be suppressed.

[0106] Regarding the optical axis asymmetry, in the interference exposure apparatus 100, the optical axis of the first beam B1 incident from the optical system 101 on the prism 102 and the optical axis of the second beam B2 incident from the optical system 101 on the prism 102 can be symmetric with respect to the normal line L, that is, the sum of the incident angle θ1a and the incident angle θ2a can be 0 (see FIG. 18). In this case, the first reflection surface S R 1 and the second reflection surface S R 2 are made asymmetric with respect to the normal line L, whereby optical axis asymmetry can be realized and a slant can be formed.

[0107] Also, in the interference exposure apparatus 100, the optical axis of the first beam B1 incident from the optical system 101 on the prism 102 and the optical axis of the second beam B2 incident from the optical system 101 on the prism 102 can be made asymmetric with respect to the normal line L, that is, the sum of the incident angle θ1a and the incident angle θ2a is not 0 (see FIG. 13). In this case, even if the first reflection surface S R 1 and the second reflection surface S R 2 are symmetric with respect to the normal line L, or even if the first reflection surface S R 1 and the second reflection surface S R 2 are made asymmetric with respect to the normal line L, optical axis asymmetry can be realized and a slant can be formed.

[0108] Note that the first reflection surface S R 1 and the second reflection surface S R 2 being asymmetric with respect to the normal line L means that even if one of the first reflection surface S R 1 and the second reflection surface S R 2 is rotated 180° with respect to the normal line L, it does not overlap with the other. Also, the first reflection surface S R 1 and the second reflection surface S R 2 being symmetric with respect to the normal line L means that when one of the first reflection surface S R 1 and the second reflection surface S R 2 is rotated 180° with respect to the normal line L, it overlaps with the other.

[0109] Also, as shown in FIG. 22, the prism 102 may have a first surface 131, a second surface 132, a third surface 133, and a fourth surface 134. The first surface 131 is the first incident surface S on which the first beam B1 is incident N1. The second incident surface S on which the second beam B2 is incident N 2 and the third reflection surface S described later R 3 also serve as. The second surface 132 is the emission surface S that emits the first beam B1 and the second beam B2 E .

[0110] The third surface 133 is the first incident surface S N 1. The first beam B1 incident from the first incident surface S R 3 is the first reflection surface S R 1 that reflects it toward the third reflection surface S N 2. The fourth surface 134 is the second incident surface S E 2. The second beam B2 incident from the second incident surface S R 2 is the second reflection surface S that reflects it toward the third reflection surface S R 3. A reflective film is provided on the third surface 133 and the fourth surface 134 to impart light reflectivity. The third reflection surface S which is the first surface 131 R 3 reflects the first beam B1 incident from the first reflection surface S E toward the emission surface S R and reflects the second beam B2 incident from the second reflection surface S E toward the emission surface S

[0111] The first incident surface S N 1. The incident angle of the first beam B1 with respect to the first incident surface S N 1 is preferably an angle perpendicular to the first incident surface S N 1. Also, the incident angle of the first beam B2 with respect to the second incident surface S N 2 is preferably an angle perpendicular to the second incident surface S E 2. Further, the emission surface S

[0112] In this configuration, as shown in FIG. 22, when the first beam B1 is incident on the prism 102 from the first incident surface S N 1, it is reflected by the first reflection surface S R 1 and the third reflection surface S R 3 and is emitted from the emission surface S EIt is emitted from. Furthermore, the first beam B1 passes through the fluid 103 and is incident on the photosensitive material M. The second beam B2 is incident on the second incident surface S N When light enters prism 102 from point 2, it reaches the second reflection surface S. R 2 and 3 reflective surfaces S R Reflected by 3, exit surface S E It is emitted from there. Furthermore, the second beam B2 passes through the fluid 103 and is incident on the photosensitive material M.

[0113] In this configuration as well, the prism 102 and fluid 103 prevent refraction of the first beam B1 and the second beam B2, thereby suppressing the decrease in the slant angle α. In particular, by utilizing reflection from the first surface 131, the third surface 133, and the fourth surface 134, the accuracy of the incident surface can be easily improved, and the angular limitations of the incident angles θ1a and θ2a (see Figure 13) can be reduced.

[0114] Regarding optical axis asymmetry, in the interference exposure apparatus 100, the optical axis of the first beam B1 incident from the optical system 101 to the prism 102 and the optical axis of the second beam B2 incident from the optical system 101 to the prism 102 are symmetric with respect to the normal L, that is, the sum of the incident angles θ1a and θ2a is 0 (see Figure 18). In this case, the first reflective surface S R 1 and the second reflective surface S R By making point 2 asymmetric with respect to the normal vector L, optical axis asymmetry can be achieved, and a slant can be formed.

[0115] Furthermore, in the interference exposure apparatus 100, the optical axis of the first beam B1 incident on the prism 102 from the optical system 101 and the optical axis of the second beam B2 incident on the prism 102 from the optical system 101 are asymmetric with respect to the normal L, that is, the sum of the incident angles θ1a and θ2a is not zero (see Figure 13). In this case, the first reflective surface S R 1 and the second reflective surface S R Even if 2 is symmetric with respect to the normal L, or the first reflecting surface S R 1 and the second reflective surface S R By making 2 asymmetric with respect to the normal L, optical axis asymmetry can be achieved, and a slant can be formed.

[0116] Furthermore, as shown in Figures 23 and 24, the prism 102 may have a first surface 141, a second surface 142, and a third surface 143. The first surface 141 is the first incident surface S into which the first beam B1 is incident. N 1. The second incident surface S into which the second beam B2 is incident. N It serves two purposes. The second surface 142 is the emission surface S from which the first beam B1 and the second beam B2 are emitted. E That is the case.

[0117] The third surface 143 is the first incident surface S N The first beam B1, which was injected from point 1, exits from surface S. E The first reflective surface S that reflects toward R The answer is 1. A reflective film is provided on the third surface 143, giving it light reflectivity. In Figure 23, the third surface 143 is parallel to the normal L, while in Figure 24, the third surface 143 is inclined with respect to the normal L.

[0118] 1st entrance plane S N The incidence angle of the first beam B1 relative to 1 is given by the first incidence plane S N An angle perpendicular to 1 is preferable. Also, the second incident plane S N The incidence angle of the first beam B2 relative to 2 is given by the second incidence plane S N An angle perpendicular to 2 is preferable. Furthermore, the exit surface S E Preferably, it is parallel to the exposure surface E.

[0119] In this configuration, as shown in Figures 23 and 24, the first beam B1 is connected to the first incident surface S N When light enters prism 102 from point 1, it reaches the first reflective surface S. R Reflected by 1, exit surface S E It is emitted from. Furthermore, the first beam B1 passes through the fluid 103 and is incident on the photosensitive material M. The second beam B2 is incident on the second incident surface S N When light enters prism 102 from point 2, the exit surface S E It is emitted from there. Furthermore, the second beam B2 passes through the fluid 103 and is incident on the photosensitive material M.

[0120] In this configuration as well, the prism 102 and fluid 103 prevent refraction of the first beam B1 and the second beam B2, thereby suppressing the reduction of the slant angle α. This configuration is an application of Lloyd-type interference lithography, and because the prism 102 is simple, it offers excellent productivity. Furthermore, as shown in Figure 24, the first reflective surface S R By tilting 1 with respect to the normal L, it is possible to form a larger slant angle α.

[0121] Regarding optical axis asymmetry, in the interference exposure apparatus 100, the first beam B1 is on the first reflective surface S R Since the first beam is reflected and the second beam B2 is not reflected by prism 102, even if the incident angles θ1a and θ2a coincide, optical axis asymmetry can be achieved and a slant can be formed.

[0122] It is also possible to combine at least two of the feature features of the present technology described above. In other words, the various feature features described in each embodiment may be combined arbitrarily, regardless of the specific embodiment. Furthermore, the various effects described above are merely examples and not limiting, and other effects may also be exhibited. [Explanation of Symbols]

[0123] B1...First beam B2... Second beam L...Normal E... Exposure surface R…irradiation area F... Interference fringes 100... Interferometric exposure system 101…Optical system 102...Prism 103…Fluid

Claims

1. An interference exposure apparatus that performs interference exposure on an object to be irradiated in the irradiation area by superimposing a first beam and a second beam, obtained by splitting coherent light, in an irradiation area on an exposure surface, thereby causing interference. A prism having a first incident surface through which the first beam and the second beam are transmitted, a second incident surface through which the second beam is incident, and an exit surface from which the first beam and the second beam are emitted, A fluid that fills the space between the emission surface and the object to be irradiated, and through which the first beam and the second beam emitted from the emission surface pass, An optical system that splits the aforementioned light into a first beam and a second beam, incident the first beam on a first incident surface, and incident the second beam on a second incident surface. It is equipped with, The optical axes of the first beam incident on the exposure surface from the fluid and the optical axes of the second beam incident on the exposure surface from the fluid are asymmetric with respect to the normal to the exposure surface in the irradiation region. Interference exposure system.

2. An interference exposure apparatus according to claim 1, The prism has a refractive index equal to or greater than that of the object being examined. Interference exposure system.

3. An interference exposure apparatus according to claim 1, The first incident surface is configured such that the first beam that has passed through the first incident surface proceeds toward the exit surface. The second incident surface is configured such that the second beam, having passed through the second incident surface, proceeds toward the exit surface. Interference exposure system.

4. An interference exposure apparatus according to claim 3, The optical system is configured such that the optical axis of the first beam incident on the first incident surface from the optical system and the optical axis of the second beam incident on the second incident surface from the optical system are asymmetric with respect to the normal. The first incident plane and the second incident plane are symmetrical or asymmetrical with respect to the normal. Interference exposure system.

5. An interference exposure apparatus according to claim 3, The optical system is configured such that the optical axis of the first beam incident on the incident surface from the optical system and the optical axis of the second beam incident on the incident surface from the optical system are symmetrical with respect to the normal. The first incident plane and the second incident plane are asymmetrical with respect to the normal. Interference exposure system.

6. An interference exposure apparatus according to claim 1, The prism further includes a first reflecting surface that reflects the first beam incident from the first incident surface toward the exit surface, and a second reflecting surface that reflects the second beam incident from the second incident surface toward the exit surface. Interference exposure system.

7. An interference exposure apparatus according to claim 1, The prism further comprises a first reflective surface, a second reflective surface, and a third reflective surface. The first reflecting surface reflects the first beam incident from the first incident surface toward the third reflecting surface. The second reflecting surface reflects the second beam incident from the second incident surface toward the third reflecting surface. The third reflective surface reflects the first beam incident from the first reflective surface and the second beam incident from the second reflective surface toward the exit surface. Interference exposure system.

8. An interference exposure apparatus according to claim 6 or 7, The optical system is configured such that the optical axis of the first beam incident on the incident surface from the optical system and the optical axis of the second beam incident on the incident surface from the optical system are asymmetric with respect to the normal. The first reflective surface and the second reflective surface are symmetrical or asymmetrical with respect to the normal. Interference exposure system.

9. An interference exposure apparatus according to claim 6 or 7, The optical system is configured such that the optical axis of the first beam incident on the incident surface from the optical system and the optical axis of the second beam incident on the incident surface from the optical system are symmetrical with respect to the normal. The first reflective surface and the second reflective surface are asymmetric with respect to the normal. Interference exposure system.

10. An interference exposure apparatus according to claim 1, The prism further has a first reflective surface, The first incident surface is configured such that the first beam, having passed through the first incident surface, proceeds toward the first reflection surface. The second incident surface is configured such that the second beam, having passed through the second incident surface, proceeds toward the exit surface. The first reflecting surface reflects the first beam incident from the first incident surface toward the exit surface. Interference exposure system.

11. An interference exposure apparatus according to claim 1, The optical system is configured such that the optical axis of the first beam incident on the first incident surface from the optical system is perpendicular to the first incident surface, and the optical axis of the second beam incident on the second incident surface from the optical system is perpendicular to the second incident surface. Interference exposure system.

12. An interference exposure apparatus according to claim 1, The prism is positioned such that the emission surface is parallel to the exposure surface. Interference exposure system.

13. An interference exposure apparatus according to claim 1, The prism has a hydrophilic emission surface. The fluid is an aqueous liquid. Interference exposure system.

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