WO2008001935A1

WO2008001935A1 - Antireflection structure and method for producing the same

Info

Publication number: WO2008001935A1
Application number: PCT/JP2007/063242
Authority: WO
Inventors: Takamasa Tamura; Makoto Umetani; Kazuhiko Ishimaru
Original assignee: Panasonic Corporation
Priority date: 2006-06-30
Filing date: 2007-07-02
Publication date: 2008-01-03
Also published as: JP4820871B2; JPWO2008001935A1

Abstract

Disclosed are an antireflection structure and a production method thereof. Specifically disclosed is an antireflection structure which can be easily mass-produced at low cost. The antireflection structure has a surface which is provided with an antireflection arrangement for suppressing reflection of incident light wherein a plurality of fine projections are arranged. This antireflection structure is characterized in that the inverted shape wherein the recesses and projections of the antireflection arrangement are reversed is generally identical with the shape of the antireflection arrangement.

Description

Specification

Antireflection structure and manufacturing method thereof

Technical field

The present invention relates to an antireflection structure and a method for manufacturing the same.

Background art

[0002] In recent years, various optical elements have been proposed in which light reflection prevention treatment for suppressing light reflection is performed on the surface. As an antireflection treatment, for example, a film having a relatively low refractive index (low refractive index film), or a film having a low refractive index and a film having a relatively high refractive index (high refractive index film) are alternately laminated. And a process of forming an antireflection film having the same strength on the surface (for example, Patent Document 1). In general, such an antireflection film having a low refractive index film or a multilayer film is formed by vapor deposition, sputtering, or the like.

However, the process of forming an antireflection film using a vapor deposition method, a sputtering method, or the like is complicated. For this reason, the light reflection preventing film has a problem that productivity is low and production cost is high.

[0004] In addition, such an antireflection film has a problem that the wavelength dependency is large. Specifically, it has a high antireflection function for light of a predetermined wavelength (design wavelength), but does not have a sufficient antireflection function for light of other wavelengths. There's a problem. For this reason, it is difficult to achieve an anti-reflection effect over the entire visible wavelength range required for an imaging optical system or the like with a low-refractive index film or a multilayer anti-reflection film.

[0005] Furthermore, the light reflection preventing film having a low refractive index film or a multilayer film has a relatively high light reflection preventing effect with respect to the normal incident light, but when the incident angle is increased, the light reflection preventing effect is obtained. Has an incidence angle dependency that becomes smaller. That is, there is a problem that a sufficient light reflection preventing effect cannot be obtained for light having a large incident angle.

In view of such problems, for example, an antireflection structure composed of a plurality of conical protrusions arranged at a submicron pitch (hereinafter, sometimes referred to as an “antireflection uneven structure”) has been proposed. It is. In the optical element having this antireflection uneven structure, the abruptness at the optical element interface is sharp. A drastic change in refractive index is suppressed. That is, the refractive index gradually changes in the antireflection uneven structure. For this reason, light reflection on the surface of the optical element is reduced, and a high light incidence rate into the optical element can be realized. According to this antireflection uneven structure, reflection of light having a wavelength equal to or greater than the pitch between the cone-shaped protrusions can be suppressed. In addition, the anti-reflection concavo-convex structure has a relatively high anti-reflection effect even for light having a large incident angle. That is, this anti-reflection uneven structure has a small wavelength dependency and incident angle dependency. Therefore, by using this antireflection concavo-convex structure, it is possible to realize an optical element, an optical system, and the like that have a high light reflection preventing effect in a wide wavelength range. As a method for manufacturing such an antireflection structure, a combination of EB drawing and RIE etching has been proposed as disclosed in Patent Document 2.

Patent Document 1: Japanese Patent No. 2566634

Patent Document 2: JP 2001-272505 A

Disclosure of the invention

Problems to be solved by the invention

[0007] In the method for manufacturing an antireflection structure described in Patent Document 2, etc., it takes a very long time and a large manufacturing cost to manufacture the antireflection structure. Therefore, it is not preferable to directly manufacture the antireflection structure by the method described in Patent Document 2 and the like.

[0008] For example, as a method for manufacturing an antireflection structure at a low cost, a method using a replication mold for producing an antireflection structure is conceivable. According to this method, once the replica mold is manufactured, the antireflection structure can be manufactured easily and inexpensively.

[0009] In addition, as a particularly inexpensive manufacturing method, a primary replica mold is manufactured using the created antireflection structure as a mold, and a secondary replica mold is manufactured using the primary replica mold as a mold. Then, a method of manufacturing an antireflection structure using the secondary replica mold as a mold can be considered. According to this method, once the antireflection structure is produced, the secondary replica mold can be mass-produced at low cost, and the manufacturing cost of the antireflection structure can be further reduced.

[0010] However, the antireflection structure generally has a structure in which a plurality of fine conical projections are arranged as shown in FIG. For this reason, the antireflection structure and the secondary replica type have substantially the same shape. Therefore, the secondary replica mold is used to press-mold the anti-reflective structure. When manufactured, an antireflection structure as shown in Fig. 2 is produced which has an uneven shape opposite to the original antireflection structure. That is, an antireflection structure having an antireflection structure in which a plurality of concave portions corresponding to the shape of the convex portions formed in the original antireflection structure is formed.

[0011] Here, when a plurality of fine concave portions are formed, since the refractive index change in the surface layer portion becomes abrupt compared to the case where a plurality of fine convex portions are formed, sufficient antireflection is achieved. The effect may not be obtained.

Accordingly, an antireflection structure having an antireflection structure in which a plurality of fine cone-shaped projections are arranged cannot be manufactured at low cost using a secondary replica mold. There is a problem.

[0013] The present invention has been made in view of such a point, and an object of the present invention is to provide an antireflection structure that can be inexpensively and easily mass-produced.

Means for solving the problem

[0014] In order to solve the above-described object, the antireflection structure according to the present invention has a structure in which a plurality of fine convex portions are arranged and an antireflection structure for suppressing reflection of incident light is formed on the surface. The anti-reflection structure is characterized in that the shape obtained by inverting the unevenness of the anti-reflection structure is substantially the same as the shape of the anti-reflection structure.

[0015] That is, in the antireflection structure according to the present invention, the shape of the plurality of fine protrusions and the shape obtained by inverting the plurality of recesses formed by the plurality of protrusions are substantially the same. It is characterized by being.

[0016] When the first replica mold is manufactured using the antireflection structure according to the present invention as a mold, and the second replica mold is manufactured using the first replica mold as a mold, the unevenness of the antireflection structure Therefore, the microstructure formed in the first replica mold and the micro structure formed in the second replica mold are both included in the present invention. Such an antireflection structure has substantially the same shape as the antireflection structure. The antireflection structure according to the present invention can be mass-produced by the electric press molding method using the first or second replication mold. In other words, after one antireflection structure according to the present invention is produced, a large number of first or second replica molds can be produced using the produced antireflection structure as a mold. It is possible to easily and inexpensively mass-produce an antireflection structure having an antireflection structure in which a plurality of fine convex portions are arranged using a plurality of duplicate molds. Therefore, the antireflection structure according to the present invention can be mass-produced easily and inexpensively.

[0017] The first manufacturing method of the antireflection structure according to the present invention includes a plurality of fine convex portions arranged, and an antireflection structure that suppresses reflection of incident light is formed on the surface. A method for manufacturing an antireflection structure in which the shape of the irregularities of the structure is inverted and the antireflection structure is substantially the same shape. The antireflection structure is a two-beam interference exposure method or an X-ray lithography method. It is formed by.

[0018] In the second manufacturing method of the antireflection structure according to the present invention, a plurality of fine convex portions are arranged, and an antireflection structure that suppresses reflection of incident light is formed on the surface. This is a method for manufacturing an antireflection structure in which the irregularities of the structure are inverted and the antireflection structure is approximately the same shape. The antireflection structure is formed using a replication mold.

[0019] In the third manufacturing method of the antireflection structure according to the present invention, a plurality of fine convex portions are arranged, and an antireflection structure that suppresses reflection of incident light is formed on the surface. A method for manufacturing an antireflection structure in which the shape of the structure is inverted and the antireflection structure is substantially the same shape, and the object to be molded is press-molded using the antireflection structure as a mold Thus, a replica mold is manufactured, and an antireflection structure is formed using the replica mold.

The invention's effect

[0020] According to the present invention, it is possible to realize an antireflection structure that can be easily mass-produced inexpensively.

Brief Description of Drawings

FIG. 1 is a diagram of a general conical antireflection structure.

FIG. 2 is a diagram in which the concavities and convexities of the conical antireflection structure are reversed.

FIG. 3 is a schematic diagram for explaining the manufacturing method of the antireflection structure according to the first embodiment.

[FIG. 4] FIG. 4 is a schematic diagram showing the intensity distribution of X-rays formed on the substrate after exposure, and FIG. FIG. 3 is an enlarged perspective view showing the intensity distribution of X-rays irradiated onto the substrate after exposure in a three-dimensional manner.

FIG. 5 is a schematic diagram for explaining a manufacturing method of the antireflection structure according to the second embodiment.

[Fig. 6] Fig. 6 is a schematic diagram for explaining an electric wire manufacturing method according to the third embodiment.

FIG. 7 is a schematic diagram for explaining a glass replication mold manufacturing method according to the fourth embodiment.

FIG. 8 is a schematic diagram for explaining a manufacturing method of the antireflection structure according to the fifth embodiment.

FIG. 9 is a perspective view of an antireflection structure according to Embodiment 7.

FIG. 10 is a cross-sectional view of the antireflection structure according to Embodiment 7.

FIG. 11 is a cross-sectional view of another antireflection structure according to Embodiment 7.

FIG. 12 is a cross-sectional view of a mold used in the method for manufacturing an antireflection structure according to Embodiment 7.

Explanation of symbols

Q1 Quartz glass substrate

11 Conical antireflection structure

31 PMMA substrate

32 Anti-reflection structure

51 X-ray resist

52 Microstructure

53 Anti-reflection structure

61 PMMA master type

62 Anti-reflection structure

63 MZB solution

64 Electroless plating layer

65 Nickel sulfamate electrolyte

66A Ni plating layer 66B Ni plating layer

67 Base hot metal

68 Primary Ni replication type

69 Release film

60 Secondary Ni replication type

71 thin film

72 Upper mold

73 Lower mold

74 Molding materials

75 thin film

76 chamber

77 parts

81 Base type

82 Surface protective release layer

83 Electric type

84 Oil in a fluidized state

85 resin

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Embodiment 1]

Using an X-ray mask A having a Ta absorption pattern with a line width of 150 nm and a pitch of 300 nm on an SiC membrane, an antireflection structure was produced by irradiating the PMMA substrate 31 with X-rays as follows. Details will be described with reference to FIG.

[0025] The X-ray mask A was opposed to the PMMA substrate 31 so as to form a gap of 100 μm. After that, X-ray exposure was performed at 10 A · min from the X-ray mask A side (first exposure process: Fig. 3 (A)). Subsequently, X-ray mask A was rotated 90 degrees around the optical axis of the X-ray, and X-ray exposure was similarly performed from the X-ray mask A side with lOA'min (second exposure process: Fig. 3 ( B)). After X-ray exposure, the film was developed by dipping in a developer containing 2- (2-n-butoxyethoxy) ethanol as the main component. The MMA substrate 31 was processed into a microstructure 32 with a pitch of 300 nm and a height of 400 nm (development process: FIG. 3 (C)).

The pattern exposed on the PMMA substrate 31 is a square lattice with an X-ray exposure amount of 3 levels, as shown in (4-1 A) of FIG. That is, on the substrate after exposure, an area where X-rays are not exposed before and after the rotation (indicated as “0” in (4-1-1A) in FIG. 4), and a displacement force before and after the rotation once. The area where only X-rays were exposed (denoted as “1” in (4-1-1A) in Fig. 4) and the area where X-rays were exposed both before and after rotation ((4-1) in Fig. 4). — In A), “2”) is formed. When the exposed substrate is developed in this way, both the area where X-rays are exposed before and after the rotation and the area where X-rays are exposed only once both before and after the rotation are both marked with a recess by the image. Become. At this time, the formation depth of the concave portion becomes deeper when the X-ray dose to be irradiated is larger. Therefore, the concave portion becomes deeper than the area where the X-rays are exposed only once before and after the rotation of the area where the X-rays are exposed before and after the rotation. As described above, the X-ray intensity distribution corresponding to the shape in which the three-level unit structure shown in (4 1 A) of FIG. 4 is periodically formed can be obtained.

[0027] Actually, when the substrate is developed based on the X-ray intensity distribution shown in (4 1 A) of Fig. 4, the three-dimensional shown in (4 1 B) of Fig. 4 is caused by the influence of interference and side etching during development. The shape of a rectangular cross section cannot be obtained as in the case of a simple structure, and the edge portion is rounded, and the convex portion is shaped like a bell. In addition, the three-level unit structure is arranged in an array with a pitch less than the wavelength of the light whose reflectance should be reduced, and has the effect of preventing reflection incident on the surface.

[0028] It can be seen that the same structure is obtained even if the unevenness of the structure (4 1 B) in FIG. 4 is inverted, that is, “2” and “0” in (4 1 A) in FIG.

In Embodiment 1, the example in which the X-ray mask A is rotated 90 degrees around the X-ray optical axis and the pattern is superimposed is shown, but the present invention is not limited to this. For example, an example in which the X-ray mask A is rotated by 270 degrees around the optical axis of the X-ray and the pattern is superimposed may be shown, or may be rotated a plurality of times. In short, it is only necessary to rotate the X-ray mask so that the LZS patterns are finally orthogonal to each other. Also, instead of rotating the X-ray mask A, the substrate may be rotated. [0030] Regarding the rotation angle, exposure may be performed three times at 60 degrees or 120 degrees as shown in FIG. In this case, the pattern exposed on the substrate has an X-ray exposure level of 4 as shown in (4-2-A) in Fig. 4, and the shape shown in (4 2-B) in Fig. 4 by development. A structure with a rounded corner is formed. This structure is also concave-convex inverted like the structure of (4-1-1 B) in Fig. 4, that is, "3" and "0" and (2) and "1" of (4 2-A) in Fig. 4 It can be seen that even if "

[0031] In the first embodiment, in the LZS pattern of the X-ray mask A, the force with which the width of the X-ray absorption region 3 and the X-ray transmission region 4 is 1: 1 may be an arbitrary ratio. In addition, if the LZS pattern is formed so that the width varies between the vicinity of the center of rotation and the vicinity of the periphery, it is possible to make the reflectance wavelength dependent.

[0032] Although Ta was specifically mentioned as the material of the X-ray absorber, it is not limited to this. For example, the absorber may be any of Ta, Ni, Au, Cu, Ag, Cr, Fe and the like.

In the first embodiment, the antireflection structure is manufactured by X-ray lithography, but a similar shape can be manufactured by a two-beam interference (hologram) exposure method or the like.

[Embodiment 2]

In the second embodiment, quartz that is not PMMA is used for the substrate. A method for forming an antireflection structure on the surface of a quartz glass substrate by X-ray lithography will be described with reference to FIG.

A quartz glass substrate Q1 was cut into a size of 20 mm × 20 mm × 5 mm, and the surface was smoothly polished to a centerline surface roughness Ra = 2 nm. An X-ray resist 51 having a thickness of 0.3 μm was formed on the surface of the quartz glass substrate Q1 by spin coating. An X-ray mask A was opposed to a quartz glass substrate Q1 coated with an X-ray resist 51 through a gap of 100 m. Thereafter, X-ray exposure was performed from the X-ray mask A side with lOA'min (first exposure step: FIG. 5 (A)). Subsequently, the X-ray mask A was rotated 90 degrees around the optical axis of the X-ray, and X-ray exposure was similarly performed from the mask A side with lOA'min (second exposure process: Fig. 5 (B)) ). After X-ray exposure, the X-ray resist 51 is shown in (4-1-1B) in Fig. 4 as a result of being immersed in a developer containing 2- (2-n-butoxyethoxy) ethanol as the main component. Based on the three-dimensional intensity distribution, a pitch of 300 nm was obtained (development process: Fig. 5 (C)). [0036] Next, the quartz glass substrate Ql on which the fine structure 32 made of the X-ray resist is formed is placed in an RF dry etching apparatus, and the surface of the quartz glass substrate is etched using CHF +0 gas.

3 2

The anti-reflection structure 33 having a pitch of 300 nm and a height of 400 nm was formed on the surface of the quartz glass substrate Q1 by the etching process (structure formation process: FIG. 5 (D)). Similarly to the antireflection structure produced in the first embodiment, the antireflection structure 53 has the same shape even if it is inverted.

[0037] According to the manufacturing method shown in FIG. 5, after forming an etching mask on the quartz glass substrate Q1 before X-ray resist coating, wet etching and dry etching are performed after X-ray exposure and development. When this is done, a structure having a larger height can be obtained. In this case, the etching mask is preferably Cr, Ni, or Fe.

[0038] (Embodiment 3)

A method of replicating a mold for manufacturing a member having an antireflection structure will be described with reference to FIG. FIG. 6 is a schematic diagram for explaining a method of manufacturing an electric type used in a method for manufacturing a member having an antireflection structure according to the third embodiment. The method for producing a member having an antireflection structure according to the third embodiment is characterized in that the mold is electrically duplicated. Hereinafter, a process for electrically replicating the PMMA substrate 61 on which the antireflection structure formed by the manufacturing method of Embodiment 1 is formed will be described as an example.

[0039] Since the PMMA substrate 61 (master type, FIG. 6 (A)) is not electrically conductive by the manufacturing method described in the first embodiment, it is immersed in the NiZB solution 63 for electroless plating so as to prevent reflection. An electroless plating layer 64 was formed on the surface of the body 62 (FIG. 6 (B)). The electroless plating layer 64 formed on the antireflection structure 62 of the PMMA substrate 61 had a thickness of 30 nm. The master type in which the electroless plating layer 64 was formed was immersed in a nickel sulfamate electrolyte 65 and electroplated to form a Ni plating layer 66A on the surface of the master type (FIG. 6 (C)). Thereafter, the master mold with Ni plating was immersed in the base solution 67, and the PMMA substrate 61 was pulled away (FIG. 6 (D)) to obtain a Ni replication mold 68 (FIG. 6 (E)). The thickness of the Ni replica type 68 was 1. Omm.

[0040] A method for producing a secondary Ni replica mold from the primary Ni replica mold 68 obtained above will be described with reference to FIG.

[0041] A release film 69 was formed on the surface of the primary Ni replication mold 68 by sputtering (FIG. 6 (b)).

Next, the primary Ni replication mold 68 on which the release film 69 was formed was added to the nickel sulfamate electrolyte 6 Immersion into 5 and electroplating was performed to form a Ni plating layer 66B on the surface (Fig. 6 (c)). After that, the Ni-plated primary Ni replica mold 68 was also mechanically peeled off the Ni-plating layer force (Fig. 6 (d)) to obtain the secondary Ni replica mold 60 (Fig. 6 (e )).

[0042] The secondary Ni replication mold 60 obtained in this way is the same shape as the master mold and the primary Ni replication mold 68 because it has the same shape even when the concaves and convexes are inverted. In addition, even if secondary and subsequent, that is, tertiary and quaternary replica molds are produced, a mold having the same shape can be obtained. Also, since both the primary replica mold and the secondary replica mold have the same shape, the molded products using these molds also have the same shape.

[0043] Since the mold duplicated as described above can be duplicated many times, it can be duplicated at a very low cost. In addition, since these replica molds can be used as a mold for directly molding heat-softened rosin glass or the like, an antireflection structure can be produced at a low cost.

[Embodiment 4]

Next, referring to FIG. 7, in the method for manufacturing a member having an antireflection structure according to the fourth embodiment, another method for duplicating a mold for manufacturing the member having the antireflection structure is described. This represents a method for producing a glass mold to be used.

[0045] On the surface of the quartz glass substrate on which the antireflection structure is formed by the manufacturing method described in the second embodiment, a thin film 71 for surface protection having Ir—Rh force is formed by 0.01 μm by sputtering. The upper mold 72 for molding was formed. The lower mold 73 was formed by forming a thin film 71 with a thickness of 0.03 / zm on the surface of a cemented carbide containing WC as a main component by sputtering using Ir—Rh force. As the molding glass material 74, a crown-based borosilicate glass (transition point Tg: 501 ° C, yield point At: 549 ° C) is used, and boron nitride (BN) is used as a release agent on the surface. A thin film 75 was formed.

[0046] The upper mold 72 and the lower mold 73 were placed facing each other in a molding machine, and a molding glass material 74 was placed between them (FIG. 7 (A)). The upper mold 72, the lower mold 73, and the molding glass material 74 are all housed in a chamber 76 that is replaced with nitrogen gas. Press-molded for 3 minutes at a temperature of 590 ° C and a pressure of 1000N (Fig. 7 (B)), and the upper mold 72 was released without cooling, and the reversal shape of the anti-reflection structure on the surface of the molding material 74 To form a member 77 (FIG. 7C). afterwards, The member formed from the lower mold 73 was taken out, and the manufacturing process of the member 77 having the antireflection structure was completed. Without a surface-protecting thin film, the glass material will be in direct contact with the mold, causing fusion and making it impossible to release the mold force. If you try to release the mold forcibly, the glass material or mold will break.

[0047] The mold replicated as described above can be used as a mold for directly molding heat-softened rosin glass or the like. According to the fourth embodiment, it is possible to manufacture the mold used for forming the antireflection structure without using a high-cost and low-productivity method such as electron beam drawing.

[0048] (Embodiment 5)

Next, another method for manufacturing a member having an antireflection structure will be described with reference to FIG. FIG. 8 is a schematic diagram for explaining a method for manufacturing a member having an antireflection structure according to the fifth embodiment. The fifth embodiment is characterized in that a member made of an optical resin is molded using a mold that is electrically replicated from the master mold described above.

[0049] The electric mold 83 described above is used as an insert mold, incorporated into the base molds 81 and 82, and a silane coupling agent is applied to the entire cavity inner surface filled with the resin to form the surface protective release layer 82. (Fig. 8 (A)). Next, the electric mold 83 was heated to 220 ° C., and the polyolefin resin 84 in a fluid state was injected into the mold (FIG. 8 (B)) and filled (FIG. 8 (C)). When the resin solidified by cooling, the mold was opened and the resin was taken out to obtain resin 85 in which an antireflection structure was formed. In this embodiment mode, acrylic, Teflon (registered trademark), polyethylene, polyolefin, polycarbonate, or the like can be used as the resin material.

[0050] (Embodiment 6)

The sixth embodiment is characterized in that a member made of optical resin is molded using a mold that is electronically replicated from the master mold car described above. An optical resin material was press-molded by using a molding machine similar to that of Embodiment ⁴ using an electric replica type in which a surface protective film was formed with a silane coupling agent. The electric replica type with a surface protective film was used as the upper die, and the cemented carbide containing WC as the main component was used as the lower die. The upper mold, the lower mold, and the PMMA resin substrate were set and press-molded at 180 ° C. and 20 MPa to form an antireflection structure on the surface of the resin substrate. The embodiments are acrylic, Teflon (registered trademark), polyethylene, polyolefin, and polycarbonate. Bonates and the like can be used as the resin substrate.

[0051] (Embodiment 7)

The antireflection structure according to Embodiment 7 has a periodic structure in which convex structural units and concave structural units are alternately arranged in an array as shown in FIGS. The concave-shaped structural unit is generally conical or bell-shaped, while the convex structural unit is a general cone-shaped or bell-like shape obtained by inverting the concave shape and has a tip portion thereof. It has a cut shape. Note that the antireflection structure actually obtained has a structure in which the shape of a rectangular cross-section is not obtained as shown in FIG. 9 due to the influence of interference and side etching at the time of image formation, and the edge portion is distorted. It becomes.

[0052] Alternatively, the antireflection structure according to Embodiment 7 has a periodic structure in which convex structural units and concave structural units are alternately arranged in an array as shown in FIG. The concave-shaped structural unit is generally conical or substantially bell-shaped, while the convex-shaped structural unit is generally conical or substantially bell-shaped obtained by inverting the concave shape and The radius of curvature of the tip is larger than the radius of curvature of the concave bottom end.

[0053] The antireflection structure having the antireflection structure according to Embodiment 7 can tolerate the occurrence of air pockets in which the transferability of the tip of the convex shape is lowered when it is molded by injection molding or press molding. It has a shape like this. As a result, the formation of the antireflection structure by injection molding or press molding enables mass production easily and inexpensively.

That is, the method for manufacturing an antireflection structure described in Patent Document 2 and the like has a problem that it requires a very long time and a large manufacturing cost to manufacture the antireflection structure. Therefore, as a method of manufacturing the antireflection structure at low cost, for example, a method of forming the antireflection structure by injection molding or press molding using a master or replica of the antireflection structure as a molding die is conceivable.

[0055] When a fine structure such as an antireflection structure is formed by injection molding or press molding while pressing, the convex portion of the antireflection structure, that is, the void at the tip of the concave portion of the molding die. It is difficult to perform injection molding with good transferability because the air does not escape, that is, air accumulation occurs and the resin is not completely filled immediately. There is vacuum forming as a method to prevent air accumulation. However, since the molding cost is high, the injection that an antireflection structure can be manufactured at low cost. There is a problem that the merit of molding is lost. Therefore, an antireflection structure that is inexpensive and can be easily mass-produced is desired!

[0056] On the other hand, according to the seventh embodiment, it is possible to realize an antireflection structure that can permit air accumulation due to injection molding of the antireflection structure and can be easily mass-produced at low cost.

[0057] Such an antireflection structure is formed by using the antireflection structure produced by the X-ray exposure according to the first embodiment as a master, and using the antireflection structure according to the third embodiment. A body replica mold can be produced and manufactured by injection molding according to Embodiment 5 using the replica mold.

It should be noted that the antireflection structure as a master can be manufactured by the manufacturing method according to the second embodiment. The master of the antireflection structure made of the quartz glass substrate manufactured in Embodiment 2 has high heat resistance and high strength, and can be used as it is as a mold for injection molding. When making a large number of replica molds from a single master, such as the second and third replica molds, which can be obtained only by the first replica, the replica molds are manufactured from the anti-reflection structure master disk using a quartz glass substrate by Ni electroplating. May be. In addition, a replica type of the antireflection structure can also be manufactured by the method of the fourth embodiment. Further, the manufacturing of the antireflection structure using the replica mold may be the method according to the sixth embodiment. Furthermore, the antireflection structure produced by the manufacturing method according to the first or second embodiment can be used as a master, and can be manufactured by the manufacturing method according to the fifth or sixth embodiment using the master.

[0059] That is, in the production of the master and the replica type according to the first, second, and third embodiments, the concave structural unit is substantially conical or bell-shaped, while the convex structural unit is the concave shape. Thus, an antireflection structure having an antireflection structure that is substantially conical or bell-shaped in which is inverted is formed. On the other hand, for the production of the replica type and antireflection structure according to the above-mentioned Embodiments 4, 5, and 6, the concave structural unit is substantially conical or bell-shaped, whereas the convex structure The unit is a general cone-shaped or bell-shaped with inverted concave shape and the shape of the tip is cut, or a general cone-shaped or inverted bell-shaped inverted concave shape, with the tip of the tip The curvature radius may be larger than the curvature radius of the concave bottom end. [0060] In this way, the method of manufacturing an antireflection structure capable of allowing the occurrence of air accumulation is, in other words, the manufacture of an antireflection structure having an antireflection structure that suppresses reflection of incident light on the surface. The antireflection structure is a periodic structure in which convex structural units and concave structural units are alternately arranged in an array, and has a region obtained by inverting the periodic structure. A step of preparing a mold so as to form a cavity, a step of injecting and filling the heat-softened resin into the mold cavity, a member by cooling the resin and releasing the mold force Forming a step. In the mold, the concave structural unit is substantially conical or substantially bell-shaped, while the convex structural unit is substantially conical or substantially bell-shaped obtained by inverting the concave shape. It shall be.

[0061] The cross section of the mold in the method for producing an antireflection structure according to the present invention has a structure as shown in FIG. That is, the molding die in this manufacturing method is characterized in that the convex shape and the shape obtained by inverting the convex and concave portions and the shape before being inverted are substantially the same.

[0062] Since the shape of the unevenness of the antireflection structure in the mold is inverted and the shape before being inverted are substantially the same, the fine structure (antireflection structure) formed in the first replica mold, Both the microstructure (antireflection structure) formed in the second replica mold produced using the first replica mold as a mold have substantially the same shape. In other words, the molding die in the method for manufacturing an antireflection structure according to the present invention can produce a large number of second or third replica molds by using the antireflection structure itself produced thereby as a molding die. An antireflection structure having an antireflection structure in which a plurality of fine convex portions are arranged using the produced replica mold can be more easily and inexpensively mass-produced.

[0063] Further, the step of preparing the molding die is to produce the molding die so as to form the above-described cavity using an antireflection structure produced by a two-beam interference exposure method or an X-ray lithography method. May be.

[0064] Further, in the step of preparing the mold, a replica mold is manufactured from the antireflection structure manufactured by the two-beam interference exposure method or the X-ray lithography method, and the above-mentioned cavity is formed using the replica mold. You can also make a mold to form.

[0065] Furthermore, the step of preparing the mold includes a two-beam interference exposure method or an X-ray lithography. A replica mold is manufactured by press molding a molded object using an antireflection structure manufactured by a method, and the mold is manufactured using the replica mold to form the above-described cavity. Also good.

[0066] Prior to the formation of the antireflection structure, it is preferable to form a release layer on the surfaces of the mold and Z or the duplicate mold.

[0067] Further, it is preferable that the pitch between the concave shapes is equal to or less than the wavelength of light whose reflection is suppressed by the antireflection structure.

[0068] Furthermore, the antireflection structure is preferably an optical member.

Industrial applicability

[0069] The present invention is suitable for an optical element having an optical function surface that requires antireflection processing for light rays in an optical path, such as a lens element and a prism element used in a digital camera, a printer device, and the like. In addition, the present invention is applied to a structural member used for holding these optical elements, for example, a casing member that protects the entire device including the optical element, thereby providing an antireflection surface that prevents unnecessary light. it can. Furthermore, the present invention is applicable to various devices such as light emitting elements such as semiconductor laser elements and light emitting diodes, light receiving elements such as photodiodes, imaging elements such as CCDs and CMOSs, and optical switches and branching devices used for optical communication. In addition, the function of each device can be improved by forming it in a portion requiring antireflection treatment. Furthermore, the present invention may be applied to the display portion of a display panel such as a liquid crystal display panel, an organic electrification luminescence panel, or a plasma light emission panel! / ヽ. In addition, the present invention is widely applicable to all members that require antireflection treatment used in optical equipment.

Claims

The scope of the claims

[1] An antireflection structure in which a plurality of fine protrusions are arranged and an antireflection structure for suppressing reflection of incident light is formed on a surface,

An antireflection structure, wherein the shape of the antireflection structure with the irregularities inverted is substantially the same as the shape of the antireflection structure.

[2] In the antireflection structure according to claim 1,!

The antireflection structure body, wherein a pitch between the plurality of convex portions is equal to or less than a wavelength of light at which reflection is suppressed by the antireflection structure.

[3] In the anti-reflection structure according to claim 1,!

An antireflection structure, which is an optical member.

[4] A plurality of fine convex portions are arrayed, and an antireflection structure that suppresses reflection of incident light is formed on the surface. The shape in which the unevenness of the antireflection structure is inverted, and the antireflection structure Is a method for manufacturing an antireflection structure having substantially the same shape,

The antireflection structure is formed by a two-beam interference exposure method or an X-ray lithography method.

[5] A plurality of fine convex portions are arrayed, and an antireflection structure that suppresses reflection of incident light is formed on the surface. The shape obtained by inverting the unevenness of the antireflection structure, and the antireflection structure Is a method for manufacturing an antireflection structure having substantially the same shape,

A method for producing an antireflection structure, comprising producing a replica mold by electric plating using the antireflection structure as a mold, and forming the antireflection structure using the replica mold.

[6] A plurality of fine protrusions are arrayed, and an antireflection structure that suppresses reflection of incident light is formed on the surface. The shape obtained by inverting the unevenness of the antireflection structure, and the antireflection structure Is a method for manufacturing an antireflection structure having substantially the same shape,

An antireflection structure characterized in that a duplicate mold is produced by press molding a molding using the antireflection structure as a mold, and the antireflection structure is formed using the replica mold. Manufacturing method.

[7] In the method of manufacturing an antireflection structure according to claim 5 or 6,

Prior to forming the antireflection structure, a release layer is formed on the surface of the replica mold. A method for producing an antireflection structure, comprising: