Exposure device

Abstract

To provide an exposure device that enables batch exposure of irregular patterns onto external surfaces of complex three-dimensional structures, including columnar and cylindrical configurations.SOLUTION: The present invention provides an exposure device 100 that exposes a target M with speckle light SL, where the exposure device includes: a light source 10 that emits coherent light; a hollow sphere 30 disposed on an optical axis AX(L) of the light source 10, with a scattering material applied or disposed on its inner surface 30a; and an exposure target holder 50 capable of retaining the target M having a photosensitive material applied thereto, inside the hollow sphere 30.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an exposure apparatus. [Background technology]

[0002] In recent years, it has become known that by processing micro to sub-micrometer structures onto the surface of a material, it is possible to add functions that the material does not have. In addition, the size of the structure created on the surface can greatly affect its function, leading to a wide range of uses. Although there are also changes depending on the arrangement and shape of the structure, in the field of biomimetics, the following functions can be added even if the arrangement or structure is irregular.

[0003] Examples of functions that can be added include antibacterial properties (for use on doorknobs and handles), water repellency and hydrophilic properties (for example, the effect of improving dispensing residue by processing the tip of a pipette tip, and use in dispensing equipment, medical equipment, and analytical equipment), high lubricity (for example, reducing wear and friction on sliding parts. By micro-processing (dimples) on the metal surface and storing oil there, the effect of reducing wear and friction on sliding parts can be achieved), and friction reduction effects (for example, improving sliding properties by controlling frictional force by reducing the contact area. In the automotive industry, Examples of applications include improving the combustion energy of engines in a space-saving manner and improving the lifespan of parts by suppressing deterioration), adding light diffusion properties (for example, as a light diffusion plate), adding high adhesion (for example, adding a structure like a gecko's foot, improving the adhesion of functional thin films such as DLC (diamond-like carbon) and hydroxyapatite which increases biocompatibility, and for use in adsorption and transport of microscopic objects and as a sealing material), and adding an anti-reflection effect (for example, preventing reflection on lenses by adding a sub-wavelength structure, used on the metal surfaces of transparent optical elements and solar cells).

[0004] In recent years, there has been an increasing need for micromachining of cylindrical parts and parts with complex shapes (to improve engine combustion energy in the automotive industry and to improve the lifespan of parts due to deterioration). There are examples where laser processing has reduced friction and improved the dynamic pressure performance of engines. In this example, methods for manufacturing fine structures on metal surfaces include mechanical processing for the micro order, and direct processing methods using energy beams (ion beams, femtosecond lasers (ultra-short pulse lasers), high-power lasers such as thermal lithography) for the sub-micro order, as well as methods using electron beams and synchrotron light, which can produce highly accurate structures. There is also a strong demand for microprocessing on the surfaces of structures that have curved surfaces, not just flat ones. However, in the method using energy beams, not only are the lasers themselves expensive, but they cannot process a wide variety of shapes other than flat surfaces. In addition, since structures are processed one by one, a significant amount of processing time is required. For this reason, it is not easy to use when prototyping products, and its applications are limited. There is no simple and inexpensive processing method that can be used for three-dimensional structures.

[0005] Meanwhile, lithography technology that applies speckle light has been attracting attention as a technology that can transfer fine patterns without the need for a reduction projection lens. When coherent light such as laser light is scattered by a scattering material, speckle light generates a local light intensity distribution with an irregular (random) arrangement and shape in space due to the interference and diffraction phenomenon of light. By utilizing the irregular (random) arrangement and shape of the light intensity distribution called speckle light and applying it to a surface coated with photosensitive resin, it is possible to create fine photosensitive resin patterns on the order of micro to nano. Furthermore, by using this as a masking material for metal etching, it is possible to create fine structures on the metal surface.

[0006] For example, there is an exposure technique described in Patent Document 1 for the production of irregular (random) structures. However, even in this lithography technique that applies speckle light, there is no example that shows a means for realizing exposure to a three-dimensional structure other than a flat surface. Furthermore, a technique that only applies light from one direction, such as the back side of a cylinder, cannot simultaneously process the parts that are not exposed to light. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2005-140967 A Summary of the Invention [Problem to be solved by the invention]

[0008] The method disclosed in Patent Document 1, in which light is applied to a diffuser plate to generate speckle light and the speckles are projected onto an exposed object coated with a photosensitive resin to transfer a fine pattern, is intended for flat plates, and cannot transfer a pattern with high accuracy when the exposed object is, for example, a column, a cylinder, or the surface of a three-dimensional structure with a complex shape including steps. This is because the master diffuser plate is flat, and it is known that the local light intensity distribution of the speckle light depends on the distance from it. For this reason, if the distance from the master diffuser plate to the surface on which the light hits is different, such as in the case of a cylinder or columnar shape, the pattern dimensions will change or the light intensity will be too weak to form a pattern. Furthermore, the back side of the material that is not exposed to light cannot be processed in one go, regardless of the processing method used. For this reason, a mechanism for changing the posture of the workpiece is required, which significantly increases costs and processing time.

[0009] For example, it would be useful if we could transfer random patterns made with speckle light more easily and at low cost to exposed objects that are cylindrical or columnar, or have complex three-dimensional structures with steps. Furthermore, if it were possible to transfer the pattern all at once with a single exposure, it would be possible to apply the resist pattern to the surface in a short time, which would reduce manufacturing costs.

[0010] The present invention has been made in consideration of the above circumstances, and has an object to provide an exposure apparatus capable of simultaneously exposing the entire periphery of the outer surface of a three-dimensional structure having a complex shape, including a columnar or cylindrical shape. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides the following means.

[0012] A first aspect of the present invention is an exposure apparatus that exposes an object to be exposed using speckle light, comprising: a light source that emits coherent light; a hollow sphere that is arranged on the optical axis of the light source and has a scattering material applied or placed on its inner surface; and an object to be exposed that is capable of holding an object to be exposed that has a photosensitive material applied thereto within the hollow sphere.

[0013] A second aspect of the present invention relates to an exposure apparatus according to the first aspect, which includes a light-blocking scattering member that is positioned within the hollow sphere closer to the light source than the object to be exposed and is fixed in a direction such that the coherent light strikes a surface on which a scattering material is applied or placed.

[0014] A third aspect of the present invention is an exposure apparatus according to the first aspect, further comprising a light diffusion plate disposed on the optical axis of the light source, near the light entrance opening of the hollow sphere.

[0015] A fourth aspect of the present invention is an exposure apparatus that exposes the outer surface of an object to be exposed using speckle light, comprising: a light source that emits coherent light; a first hollow sphere that is arranged on the optical axis of the light source, has a scattering material applied or placed on its inner surface, and has a scattered light passing opening through which a portion of the light scattered at the inner surface exits; a second hollow sphere that has a communicating opening that communicates with the first hollow sphere via the scattered light passing opening and an insertion opening for inserting the object to be exposed, and has a scattering material applied or placed on its inner surface; and an object to be exposed that can hold an object to be exposed that has a photosensitive material applied thereto within the second hollow sphere. Effect of the Invention

[0016] According to the exposure apparatus of the present invention, it is possible to provide an exposure apparatus capable of collectively exposing the entire periphery of the outer surface of a three-dimensional structure having a complex shape, including a columnar or cylindrical shape. [Brief description of the drawings]

[0017] [Figure 1]1 is a cross-sectional schematic diagram showing a schematic configuration of an exposure apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a schematic plan view of the exposure apparatus shown in FIG. [Diagram 3] FIG. 11 is a plan view illustrating a schematic configuration of an exposure apparatus according to a second embodiment. [Figure 4] FIG. 11 is a plan view illustrating a schematic configuration of an exposure apparatus according to a third embodiment. [Diagram 5] FIG. 13 is a plan view illustrating a schematic configuration of an exposure apparatus according to a fourth embodiment. [Figure 6] FIG. 1 is a flow chart showing a procedure of step exposure. [Figure 7] 1 is an optical microscope photograph of a cylindrical stainless steel sample on which a resist pattern has been formed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention will be described in detail below with reference to the drawings as appropriate. The drawings used in the following description may show characteristic parts in an enlarged scale for the sake of convenience in order to make the characteristics easier to understand, and the dimensional ratios of each component may differ from the actual ones. The dimensions and the like exemplified in the following description are merely examples, and the present invention is not limited thereto, and may be appropriately modified and implemented within the scope of the effects of the present invention. Hereinafter, a configuration described in one embodiment may be applied to other embodiments, even if not specifically described otherwise.

[0019] (First embodiment) Fig. 1 is a cross-sectional schematic diagram showing a schematic configuration of an exposure apparatus according to a first embodiment, Fig. 2 is a plan schematic diagram of the exposure apparatus shown in Fig. 1. The exposure apparatus 100 shown in Figure 1 is an exposure apparatus that exposes an exposed object M using speckle light SL, and includes a light source 10 that emits coherent light, a hollow sphere 30 that is arranged on the optical axis AX(L) of the light source 10 and has a scattering material applied or placed on the inner surface 30a, and an exposed object holding section 50 that is capable of holding an exposed object M coated with a photosensitive material within the hollow sphere 30. By using the exposure apparatus 100, the entire circumference of the outer surface Ma of the exposure object M can be exposed in one go.

[0020] The exposure apparatus 100 shown in FIG. 1 further comprises a hollow sphere support 60 that supports the hollow sphere 30, a light source support 70 that supports and fixes the light source 10 via a support and fixation base 20, and a mounting base 1 on which the entire exposure apparatus is mounted.

[0021] <Exposure principle of this exposure device> When coherent light is applied to a scattering material, scattered light is generated, and the interference of this scattered light generates speckle light, a fine, localized, spotted light intensity distribution with random shapes at random positions. By utilizing this property, coherent light is applied to the inner surface of a hollow sphere on which a scattering material is applied or placed, and speckle light is generated in all directions by the scattered light inside the hollow sphere. Furthermore, the scattered light is repeatedly reflected inside the hollow sphere, resulting in a state in which the hollow sphere has a fine, localized spotted light intensity distribution, and this localized spotted light intensity distribution exists uniformly throughout the entire interior of the hollow sphere. An object to be exposed, coated with photosensitive resin, is placed inside a hollow sphere and exposed to the speckle light, causing localized exposure in areas where the light is strong. Therefore, even if the object to be exposed has a complex shape, placing it inside a hollow sphere allows the speckle light to hit it from all directions, and a pattern can be transferred in all directions at once with a single exposure. Subsequent development processing allows the exposed areas to be selectively removed or left, forming a fine resist pattern.

[0022] <Light source> Examples of the light source 10 that emits coherent light include a laser and an LD (laser diode). The light source can emit coherent light containing a photosensitive wavelength of the photosensitive material to be applied to the object M to be exposed. Furthermore, an optical fiber can be attached to the light source to guide the light to the exposure device and connect it with an FC connector. Using an FC connector improves the reproducibility of attachment and detachment, so changing the wavelength of the light source when changing the photosensitive material does not require a large-scale optical system, and can be done by simply replacing the light source.

[0023] Furthermore, the light from the light source can be turned on and off not only by turning the power source of the light source on and off, but also by opening and closing a shutter (not shown) that is provided between the light source and the hollow sphere.

[0024] In the exposure apparatus 100, the light source 10 is arranged outside the hollow sphere 30, but it may be arranged inside the hollow sphere 30. Furthermore, exposure apparatus 100 is configured to let coherent light from light source 10, which is placed outside hollow sphere 30, pass through light entrance opening 30A and enter hollow sphere 30. Furthermore, an illumination optical system that controls the illumination area may be provided between light source 10 and hollow sphere 30. A configuration may also be used in which the light beam emitted from light source 10 is enlarged or reduced by the illumination optical system, and introduced into hollow sphere 30 at a predetermined size. When an illumination optical system is provided, it is preferable to include a beam expander to expand the illumination area.

[0025] In order to prevent the coherent light L entering the hollow sphere 30 from directly hitting the exposed object M, it is preferable that the direction of the optical axis AX(L) of the light source 10 is offset from the direction AX(M) in which the exposed object M extends, as shown in Figure 2. In FIG. 2, coherent light L emitted from the light source 10 travels in the direction of the optical axis AX(L) and first strikes the inner surface 30a of the hollow sphere 30, without striking the object M to be exposed directly.

[0026] <Hollow sphere> The hollow sphere 30 is placed on the optical axis AX of the light source 10, and a scattering material is applied or placed on the inner surface 30a. The scattering material applied to the inner surface 30a may be a perfect diffusion material, such as silicone paint, barium sulfate paint, Spectraflect, Spectralon, etc., which scatters light with high reflection. It may also be a material attached, such as a volume scatterer made of small particles. It should be noted that the provision that "a scattering material is applied or placed on the inner surface" includes configurations in which a scattering material is applied to the inner surface of a hollow sphere, configurations in which a scattering material is attached to the inner surface of a hollow sphere, and configurations in which the inner surface of a hollow sphere is directly roughened to create a scattering surface. In the exposure apparatus 100, the light source 10 is arranged outside the hollow sphere 30, so that the hollow sphere 30 has a light entrance opening 30A through which coherent light is incident. Furthermore, the exposure apparatus 100 has an insertion opening 30B through which the exposure object M is inserted from the outside of the hollow sphere 30.

[0027] Coherent light L emitted from light source 10 strikes the inner surface 30a of hollow sphere 30, which is coated or disposed with a scattering material, and speckle light is generated by interference of the scattered light. Inside the hollow sphere, speckle light is generated randomly in all directions, and further scattering is repeated, resulting in a high spatial uniformity of the internal light intensity distribution. When an exposure object M coated with a photosensitive resin is placed inside hollow sphere 30 in this state and exposed to the speckle light, the areas with strong light are locally exposed to light.

[0028] The hollow sphere 30 may be an integrating sphere.

[0029] <Exposed object> A typical example of the exposure object M is a solid or hollow cylindrical object. The cross section may be a three-dimensional object with a curved outer periphery such as a circle or an ellipse, or a polygonal shape such as a rectangle. Furthermore, a three-dimensional structure having a portion with a complicated shape such as a step is also a target for the exposure object M. In the exposure apparatus 100, exposure is performed in an exposure environment in which the light intensity distribution is highly spatially uniform, so even an object having a portion with a complicated shape such as a step is exposed to light from all directions, and the entire circumference of the outer surface can be exposed in one go in a single exposure.

[0030] An example of the object to be exposed M is a three-dimensional structure made of metal such as stainless steel or brass. When the object to be exposed M is exposed, the object to be exposed is exposed in a state in which a photosensitive material (resist) is attached to its outer surface Ma with a predetermined thickness (for example, 1 μm to several hundreds of μm). The object to be exposed M is held in a detachable state by a holding mechanism such as a vice (not shown).

[0031] <Exposed object holding section> In the exposure apparatus 100, the exposure object M is held inside the hollow sphere 30 by an exposure object holding part 50 provided outside the hollow sphere 30, but an exposure object holding part that fixes the exposure object M may also be provided inside the hollow sphere 30. The exposure object holder provided outside the hollow sphere 30 preferably includes a movement mechanism (exposure object movement mechanism) for moving the position and orientation of the exposure object, either separately or integrally. The exposure object holder 50 has a moving mechanism capable of translationally moving from the outside of the hollow sphere 30 into the hollow sphere 30 .

[0032] The exposure object holding part 50 is placed on the placement table 1. The exposure object holding part 50 includes a gripping part 50a for gripping the exposure object M, a fixed part 50b on which the gripping part 50a is placed and fixed, a rotation stage 50c on which the fixed part 50b is placed and which is rotatable about the x-axis and the y-axis, a z-axis translation stage 50d on which the rotation stage 50c is placed and which is capable of translational movement in the z direction (direction perpendicular to the xy plane), a z-axis rotation stage 50e on which the z-axis translation stage 40c is placed and which is rotatable about the z-axis, and an xy-axis translation stage 50f on which the z-axis rotation stage 50e is placed and which is capable of translational movement in two axial directions, the x-axis and the y-axis.

[0033] Once the positioning of the object to be exposed M is complete, exposure is performed for a specified time using an exposure light source having a wavelength to which the resist is sensitive. The exposure time can be determined by turning the power of the light source on and off, or by limiting the light using a shutter installed at the light source or between the light source and the hollow sphere. The object M is exposed for a predetermined time and then developed to form a resist pattern. When a positive resist is used, the resist is removed where light hits it, and when a negative resist is used, the area where light hits it remains as a structure. As a negative resist, for example, PMER CA3000 (Tokyo Ohka Kogyo Co., Ltd.) can be used. Furthermore, as a positive resist, for example, THMR-iP3300 (Tokyo Ohka Kogyo Co., Ltd.) can be used.

[0034] <Hollow sphere support part> The hollow sphere support portion supports the hollow sphere from below. The hollow sphere support preferably includes a movement mechanism (hollow sphere movement mechanism) for moving the position and orientation of the hollow sphere, either separately or integrally.

[0035] A hollow sphere support part 60 shown in Fig. 1 is placed on a mounting table 1. A hollow sphere 30 is supported by the hollow sphere support part 60 placed on the mounting table 1. The hollow sphere support part 60 supports the hollow sphere 30 and includes a support part 60a which is rotatable about the y axis, a z-axis translation stage 60b on which the support part 60a is placed and which is capable of translational movement in the z direction (direction perpendicular to the xy plane), a z-axis rotation stage 60c on which the z-axis translation stage 60b is placed and which is rotatable about the z axis, and an xy-axis translation stage 60d on which the z-axis rotation stage 60c is placed and which is capable of translational movement in two axial directions, the x axis and the y axis.

[0036] In the exposure apparatus 100 shown in FIG. 1, the hollow sphere support 60 has an x-axis translation stage 60d, and therefore the inner surface of the hollow sphere 30 can be translated in the x-axis (optical axis) direction relative to the exposure object M using the xy-axis translation stage 60d. In the exposure apparatus 100 shown in FIG. 1, the distance from the inner surface of the hollow sphere 30 to the outer surface Ma of the exposed portion M can also be changed using the x-axis translation stage 50f of the exposed object holder 50. In the exposure apparatus 100 shown in Figure 1, the distance from the inner surface of the hollow sphere 30 to the outer surface Ma of the exposed object M can be changed by using either the x-axis translation stage 60d of the hollow sphere support part 60, or the x-axis translation stage 50f of the exposed object holding part 50, or by using both.

[0037] <Light source support part> The light source support portion supports the light source from below. Furthermore, the light source support portion preferably includes a moving mechanism (light source moving mechanism) for moving the position and orientation of the light source, either separately or integrally.

[0038] 1 is placed on a mounting table 1. The light source 10 is supported by the light source support 70 placed on the mounting table 1 via a support fixing table 20. The light source support 70 includes a y-axis rotation stage 70a on which the support fixing table 20 is placed and which is rotatable about the y-axis, a z-axis translation stage 70b on which the y-axis rotation stage 70a is placed and which is capable of translational movement in the z direction (direction perpendicular to the xy plane), a y-axis rotation stage 70c on which the z-axis translation stage 70b is placed and which is rotatable about the y-axis, and an x-axis translation stage 70d on which the y-axis rotation stage 70c is placed and which is capable of translational movement in the x-axis (optical axis) direction. The light source support 70 may further include a y-axis translation stage capable of translational movement in the y direction (in a horizontal plane, a direction perpendicular to the x direction) and an x-axis rotation stage capable of rotational movement about the x axis.

[0039] <Principles of pattern formation> The resist pattern made by the present invention using speckle light has a random arrangement and shape. On the other hand, although the pattern is random, the average size of the pattern and the density of the pattern relative to the exposed area can be controlled by the relationship explained below. The size (B), shape, and pattern density (D) of the resist pattern change depending on the exposure wavelength (λ), the distance (L) from the diffusion material of the hollow sphere to the object to be exposed, the particle diameter (S) of the diffusion material, and the exposure time (t). When a small resist pattern is to be made, the exposure wavelength is shortened, the hollow sphere is made small to shorten the distance from the diffusion material to the object to be exposed, or the diameter of the object to be exposed is increased, and the surface roughness of the diffusion material is made rough. When a negative resist is used, the exposure time can be shortened to make a needle-like fine protrusion resist pattern. Increasing the exposure time increases the density of the needle-like protrusion pattern and makes it wider. When a positive resist is used, shortening the exposure time allows a resist pattern with fine localized holes to be made. Increasing the exposure time increases the density of the hole pattern and makes the dimensions larger. By further increasing the exposure time, adjacent hole patterns will eventually connect, creating a locally protruding pattern where the resist remains in parts. The size, shape, and density of the pattern can be influenced by changing one of the above conditions or by changing several of them at the same time. Changing several conditions at the same time can have a large effect. The above-mentioned effects are not possible with conventional imaging optical systems that form images, and are unique to the present invention, which utilizes the local intensity distribution of light generated by the phenomenon of optical interference and diffraction known as speckle light.

[0040] As mentioned above, factors that influence the size (B) and pattern density (D) of the resist pattern include the particle diameter (S) of the diffusing material, the distance (L) from the hollow spherical diffusing material to the exposed object, and the exposure time (t). Here, if the size R of the hollow sphere is changed, the optical path length L to the surface of the exposed object changes. Therefore, L is a function of R. L also changes depending on the radius r of the exposed object, and L becomes shorter as r increases.

[0041] The resist can be applied by known methods such as spin coating and spraying. For a simple implementation, in the case of a columnar or cylindrical object, a dip method is used in which the object is immersed in a resist solution and then pulled out. By changing the pulling speed, the thickness of the resist film applied to the surface of a columnar or cylindrical object can be controlled. In addition, in the case of an object with a complex shape, a spray method is used to apply the resist to the surface.

[0042] Second embodiment FIG. 3 is a plan view showing a schematic configuration of an exposure apparatus according to the second embodiment. The main difference between the exposure apparatus of the second embodiment and the exposure apparatus of the first embodiment is that the exposure apparatus of the second embodiment further comprises a light-blocking scattering member that is positioned inside the hollow sphere closer to the light source than the object to be exposed and is fixed so that coherent light hits the surface on which the scattering material is applied or placed. By placing a member coated with or equipped with a scattering material (light-shielding scattering member) between the incident light and the exposed object, it is possible to prevent the direct or single-reflection component of the incident light from reaching the exposed object. This makes the light irradiated onto the exposed object more uniform. In other words, by irradiating the entire surface of the exposed object with light of uniform intensity, the exposure time becomes stable, and a uniform resist pattern can be formed over the entire surface of the exposed object with a single exposure. Below, components common to the exposure apparatus according to the first embodiment will be given the same reference numerals and their description will be omitted.

[0043] The exposure apparatus 200 shown in Figure 3 is an exposure apparatus that exposes an exposed object M using speckle light SL, and includes a light source 10 that emits coherent light, a hollow sphere 30 that is arranged on the optical axis AX(L) of the light source 10 and has a scattering material applied or placed on its inner surface 30a, an exposed object holding section 50 that is capable of holding the exposed object M that is coated with a photosensitive material within the hollow sphere 30, and a light-shielding scattering member 80 that is arranged inside the hollow sphere 30 closer to the light source 10 than the exposed object M and is fixed so that the coherent light hits the surface 80a on which the scattering material is applied or placed.

[0044] <Light-shielding and scattering material> The light-blocking / scattering member 80 is disposed inside the hollow sphere 30 closer to the light source 10 than the object to be exposed M, and prevents the coherent light emitted from the light source 10 from directly impinging on the object to be exposed M. A scattering material is applied or disposed on the surface 80a of the light-blocking scattering member 80 on which the coherent light strikes. This scattering material may be a completely diffusing material, such as a silicone coating, a barium sulfate coating, or a coating of a material that highly reflects and scatters light, such as Spectraflect or Spectralon. It may also be a material to which a volume scatterer made of small particles is attached. The light-blocking / scattering member 80 may be a reflective light-diffusing plate. The light-blocking / scattering member 80 can be fixed to the hollow sphere 30 by a known fastener.

[0045] When coherent light emitted from light source 10 strikes surface 80a of light-blocking / scattering member 80, on which a scattering material is applied or disposed, speckle light is generated. The speckle light strikes inner surface 30a of hollow sphere 30 opposite surface 80a, as shown in Fig. 3, and is repeatedly reflected and scattered. As a result, speckle light is generated randomly in all directions inside the hollow sphere, and further scattering is repeated, resulting in a highly spatially uniform light intensity distribution inside.

[0046] In the exposure apparatus 200 shown in FIG. 3, a light-blocking scattering member 80 is disposed between the light source 10 and the object to be exposed M, so the optical axis AX(L) of the light source 10 may coincide with the direction AX(M) in which the object to be exposed M extends.

[0047] Third embodiment FIG. 4 is a plan view showing a schematic configuration of an exposure apparatus according to the third embodiment. The exposure apparatus according to the third embodiment differs from the exposure apparatus according to the first embodiment in that it includes a light diffusion plate that is disposed on the optical axis AX(L) of the light source 10 near the light entrance opening of the hollow sphere. Below, components common to the exposure apparatus according to the first embodiment will be given the same reference numerals and their description will be omitted.

[0048] The exposure apparatus 300 shown in Figure 4 is an exposure apparatus that exposes an exposed object M using speckle light SL, and includes a light source 10 that emits coherent light, a hollow sphere 30 that is arranged on the optical axis AX(L) of the light source 10 and has a scattering material applied or arranged on its inner surface 30a, an exposed object holding section 50 that is capable of holding an exposed object M that is coated with a photosensitive material within the hollow sphere 30, and a light diffuser plate 90 that is arranged on the optical axis AX(L) of the light source 10 near the light entrance opening 30A of the hollow sphere 30.

[0049] <Light diffusion plate> The light diffusion plate may be a surface scattering plate or a volume scattering plate, and may be any plate capable of scattering incident light to provide a uniform distribution of light intensity. The light diffusion plate 90 is a transmissive light diffusion plate. The light diffusion plate 90 may be a flat glass diffusion plate with one or both sides processed, or may be opal glass, which is a material that diffuses light inside. The light diffusion plate 90 can be fixed to the outside or inside of the hollow sphere 30 by a known fastener so as to cover the light entrance opening 30A.

[0050] When the coherent light emitted from the light source 10 hits the light diffusion plate 90, speckle light is generated. The speckle light hits the inner surface 30a of the hollow sphere 30 as shown in Fig. 4, and speckle light is generated. Inside the hollow sphere, speckle light is generated randomly in all directions, and further scattering is repeated, resulting in a highly spatially uniform light intensity distribution inside.

[0051] In the exposure apparatus 300 shown in FIG. 4, a light diffusion plate 90 is disposed between the light source 10 and the object to be exposed M, so that the optical axis AX(L) of the light source 10 and the direction AX(M) in which the object to be exposed M extends may coincide with each other.

[0052] (Fourth embodiment) FIG. 5 is a plan view showing a schematic configuration of an exposure apparatus according to the fourth embodiment. The exposure apparatus of the fourth embodiment comprises two hollow spheres, the first hollow sphere being arranged on the optical axis of the light source, having a scattering material applied or placed on its inner surface and having a scattered light passing opening through which some of the light scattered on the inner surface exits, the second hollow sphere having a communicating opening that communicates with the first hollow sphere via the scattered light passing opening and an insertion opening for inserting an object to be exposed, and differs from the exposure apparatus of the first embodiment in that the second hollow sphere is provided with an object to be exposed holding section capable of holding an object to be exposed coated with a photosensitive material. The exposure apparatus according to the fourth embodiment has a configuration in which light made uniform by a first hollow sphere enters a second hollow sphere in which an object to be exposed is placed. Below, components common to the exposure apparatus according to the first embodiment will be given the same reference numerals and their description will be omitted.

[0053] The exposure apparatus 400 shown in Figure 5 is an exposure apparatus that exposes an exposed object M using speckle light SL, and includes a light source 10 that emits coherent light, a first hollow sphere 131 that is arranged on the optical axis AX (L) of the light source 10, has a scattering material applied or placed on its inner surface 131a, and has a scattered light passing opening 131A through which a portion of the light scattered at the inner surface 131a exits, a second hollow sphere 132 that has a connecting opening 132BB that communicates with the first hollow sphere 131 via the scattered light passing opening 131AA and an insertion opening 132B through which the exposed object M is inserted, and has a scattering material applied or placed on its inner surface, and an exposed object holding section 50 that is capable of holding the exposed object M to which a photosensitive material is applied within the second hollow sphere 132.

[0054] In exposure apparatus 400, light source 10 is configured to be placed outside first hollow sphere 131, but it may also be configured to be placed inside first hollow sphere 131. In exposure apparatus 400, light source 10 is arranged outside first hollow sphere 131, and therefore first hollow sphere 131 has light entrance opening 131A through which coherent light is incident. The exposure apparatus 400 has an insertion opening 132B through which the exposure object M is inserted from the outside of the second hollow sphere 132.

[0055] In the exposure apparatus 400, coherent light emitted from the light source 10 enters the first hollow sphere 131 through the light entrance opening 131A, hits the inner surface 131a, and generates speckle light randomly in all directions. Inside the first hollow sphere 131, further scattering occurs repeatedly, resulting in a highly spatially uniform light intensity distribution inside. The light thus made uniform enters the second hollow sphere 132 through the scattered light passing opening 131AA and the communicating opening 132BB, is scattered by the inner surface 132a of the second hollow sphere 132, hits the exposed object in a state of highly spatially uniform light intensity distribution, and the areas of strong light are locally exposed.

[0056] The first hollow sphere 131 and the second hollow sphere 132 can each be supported by a hollow sphere support portion similar to that in the first embodiment. The light source 10 can also be supported by a light source support portion similar to that in the first embodiment. The exposure object M can also be held by an exposure object holder similar to that in the first embodiment.

[0057] (Exposure procedure) The procedure of step exposure will be described as an example using the flow chart of FIG. First, step S1 is a process of attaching a photosensitive substance to the exposed object. The photosensitive substance is called resist, and is a resin that reacts when light of a specific wavelength band hits it. For example, if a negative resist such as SU-8 is used, only the areas hit by light are exposed, and the resist pattern of the areas hit by light remains after development processing. If a positive resist such as THMR-iP3300 is used, only the areas hit by light are exposed, and the resist pattern of the areas hit by light is removed by current processing. The coating method is to spray the photosensitive substance or to dip the material into the photosensitive substance and then pull it out (dip coating method), which allows the material to be uniformly attached to the inner surface of the exposed object. The thickness of the film can be adjusted freely from 1 μm to several hundreds of μm.

[0058] Step S2 is a process of attaching an exposure object, which is a target for exposure, to a chuck (not shown) for fixing the exposure object. Step S3 is a process of placing an exposure object having a complex shape coated with a photosensitive material so as to be positioned inside the hollow sphere. Step S4 is a process of irradiating light from a light source onto the scattering material applied inside the hollow sphere. Step S5 is a process of exposing the object to scattered light for a predetermined time.

[0059] When the shape of the resist pattern is to be changed, the following steps are added. Between steps S2 and S3, changing the size of the hollow sphere. Between steps S3 and S4, a step of changing the light source to change the wavelength. In step S5, the exposure time is adjusted. All of these steps, or one or two of them may be carried out.

[0060] Step S6 is a process of turning off the light source when a predetermined exposure amount is reached. In step S7, if exposure is to be performed on another location, the exposure target is moved in the axial direction and / or in the direction rotating about the axis by using the movement mechanism of the exposure target holder on which the exposure target is placed, and the process returns to step S4 to start exposure on the other location. When there are no more locations to be exposed, exposure ends.

[0061] The steps after the exposure method include the following steps. Step S8 is a process of obtaining a resist pattern by development after exposure. Step S9 is a process of processing the metal surface by etching using the resist pattern as a masking material, or a process of adding a metal material onto the resist pattern by plating or the like.

[0062] The above steps omit details of bake and post-exposure bake that are typically performed with exposure.

[0063] If it is desired to continuously transfer the photosensitive resin pattern, in step S5, scanning exposure is performed in which the exposed object is continuously moved while being irradiated with light from the light source. A linear pattern can be exposed by moving the exposed object horizontally in the optical axis direction.

[0064] By the above steps, the pattern can be transferred to the entire outer periphery of the exposure object all at once. EXAMPLES

[0065] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0066] A resist pattern was produced by exposure using the exposure apparatus according to the present invention.

[0067] [Example] Figure 7 shows an optical microscope image after exposure and development processing of a stainless steel cylindrical sample with a diameter of 2 mm, which was coated with a negative resist, PMER CA3000 (Tokyo Ohka Kogyo Co., Ltd.), to a thickness of 10 μm by the dip method.

[0068] An irregular pattern of concave and convex shapes is formed, indicating that the fine resist pattern can be exposed all at once. [Explanation of symbols]

[0069] 10 light source 30 Hollow Sphere 30a Inner surface 50 Exposed object holding part 100, 200, 300, 400 Exposure equipment 131 First Hollow Sphere 132 Second Hollow Sphere

Claims

1. An exposure apparatus that exposes an object to light using speckle light, comprising: A light source that emits coherent light; A hollow sphere disposed on the optical axis of the light source and having a scattering material applied or disposed on the inner surface thereof; The exposure apparatus further comprises an exposure object holding section capable of holding an exposure object coated with a photosensitive material within the hollow sphere.

2. 2. The exposure apparatus according to claim 1, further comprising a light-blocking scattering member disposed inside the hollow sphere closer to a light source than the object to be exposed, and fixed in a direction in which the coherent light strikes a surface on which a scattering material is applied or disposed.

3. 2. The exposure apparatus according to claim 1, further comprising a light diffusion plate disposed on an optical axis of the light source near a light entrance opening of the hollow sphere.

4. An exposure apparatus for exposing an outer surface of an object to be exposed using speckle light, comprising: A light source that emits coherent light; a first hollow sphere disposed on an optical axis of the light source, the first hollow sphere having an inner surface coated or disposed with a scattering material and having a scattered light passing opening through which a portion of the light scattered on the inner surface exits; a second hollow sphere having a communication opening communicating with the first hollow sphere via the scattered light passing opening and an insertion opening into which the object to be exposed is inserted, the second hollow sphere having an inner surface coated or disposed with a scattering material; an exposure object holding section capable of holding an exposure object coated with a photosensitive material within the second hollow sphere;

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