JP2010117646A - Functional grid structure and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grid structure having a high aspect ratio and a shape applicable to various objects, and a method of manufacturing the grid structure for easily preparing the grid structure even when the size of the grid structure exceeds a wafer size. <P>SOLUTION: A plurality of narrow and linear projecting parts 2 are formed on the surface of an optically transparent support body 1 so that they are arranged in parallel with each other at a constant pitch, for example. Metal material is deposited as a functional material from an oblique direction, metal filaments 6 are formed as functional members for covering the top surfaces and side surfaces of the projecting parts 2, and a wire grid diffraction grating 10 is prepared as the grid structure. Such functional members are hollow and are simply thin layers for covering the projecting parts 2, while they effectively function similarly to a solid functional member and are prepared more easily than the solid functional member. Using various materials other than the metal material as the functional material allows achievement of various functional elements. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a functional grid structure that can be used as an optical member or an electrode assembly, and a method for manufacturing the same.

  Structures having a structure in which a large number of linear members such as a wire grid polarizer, a wave plate, and a wavelength filter are arranged in parallel with each other at a constant pitch (hereinafter sometimes abbreviated as a grid structure) are known. ing. For example, the wire grid which comprises a wire grid polarizer is the example. The wire grid polarizer is a polarizer that efficiently transmits a linearly polarized light component in a specific direction of incident light and effectively reflects a linearly polarized light component orthogonal thereto. Hereinafter, a conventional grid structure and a manufacturing method thereof will be described by taking a wire grid as an example.

  FIG. 9 is a perspective view and a partially enlarged sectional view showing the structure of the basic wire grid polarizer 100. In the wire grid polarizer 100, a large number of linear metal thin wires 102 are arranged on a transparent substrate 101 at a constant pitch P (distance between the centers of two adjacent thin wires) P in parallel with each other. As indicated by thin lines and broken lines in FIG. 9, the light incident surface is usually a surface perpendicular to the longitudinal direction of the thin metal wire 102. When light having a wavelength sufficiently longer than the pitch P is incident on the wire grid polarizer 100, a polarization component (TE polarized light) whose polarization direction is parallel to the longitudinal direction of the thin metal wire 102 is easily reflected by the wire grid polarizer 100, A polarized light component (TM polarized light) whose polarization direction is perpendicular to the longitudinal direction is easily transmitted through the wire grid polarizer 100.

  The most important factor that determines the performance of the wire grid polarizer 100 is the relationship between the pitch P of the fine metal wires 102 and the wavelength λ of the incident light. In the range where the pitch P is approximately ½ or less of the wavelength, the element shown in FIG. 9 functions as a polarizer. In the range where the pitch P is larger than about twice the wavelength, the element shown in FIG. 9 functions as a diffraction grating. In the range where the pitch P is approximately ½ to 2 times the wavelength, the reflection characteristics and the transmission characteristics change significantly. This is known as “Rayleigh resonance” and is caused by the occurrence of higher order diffracted light when incident light passes through the element shown in FIG. Before and after the wavelength at which Rayleigh resonance occurs, the performance as a wire grid polarizer is significantly reduced.

  Therefore, in order to use the element shown in FIG. 9 as the wire grid polarizer 100, the pitch P of the fine metal wires 102 should be ½ or less of the wavelength of incident light in order to avoid Rayleigh resonance. is necessary. For example, in order to polarize and separate visible light having a wavelength of 400 to 800 nm, the pitch P is required to be 400 nm / 2 = 200 nm or less.

  Other factors that determine the performance of the wire grid polarizer 100 include the pitch P of the fine metal wires 102, the ratio W / P of the width W of the fine metal wires 102 to the pitch P, the thickness T of the fine metal wires 102 in the light transmission direction, In addition, there are types of metal materials constituting the metal thin wire. As a general tendency, when the pitch P is smaller, the transmittance of TM polarized light is improved particularly in a short wavelength region. If the pitch P is constant, the degree of polarization of transmitted light increases as the thickness T of the fine metal wires 102 increases. Moreover, the transmittance | permeability of TM polarized light becomes large when the width W of the metal fine wire 102 is small. Therefore, in order to improve the performance of the wire grid polarizer 100, it is necessary to increase the ratio T / W of the thickness T to the width W, that is, the aspect ratio of the cross section of the thin metal wire 102 to a certain extent. As the metal material, it is desirable to use a metal having a high reflectance, such as aluminum or silver.

  Now, the fabrication of the wire grid polarizer usually uses a photolithography method and an etching method similar to those used in the manufacture of a semiconductor element. There has been proposed a wire grid polarizer manufactured by a lift-off method without using a photolithography method by using a transparent resin substrate having irregularities.

  FIG. 10 is a cross-sectional view showing a flow of a manufacturing method of the wire grid polarizer 110 disclosed in Patent Document 1. In this manufacturing method, first, a transparent resin substrate 111 having a wave-shaped fine concave portion 111a and convex portion 111b on one surface shown in FIG. 10A is prepared. The transparent resin substrate 111 is produced, for example, by molding a polycarbonate resin by an injection molding method using a mold to which a stamper having wave-shaped fine irregularities is attached. Regarding the size of the fine irregularities of the stamper, for example, the height of the convex portions 111b with respect to the concave portions 111a is 270 nm and the pitch is 300 nm.

  Then, as shown in FIG. 10A, a masking layer 112 made of polystyrene or the like is formed on the entire fine uneven surface of the transparent resin substrate 111 by a vacuum deposition method, a sputtering method, a chemical vapor deposition method (CVD), or the like. Form.

  Next, as shown in FIG. 10B, the masking layer 112 formed on the convex portion 111b is removed while leaving the masking layer 112 formed on the concave portion 111a of the transparent resin substrate 111, and the surface of the convex portion 111b. To expose. The selective removal of the masking layer 112 is performed using a reverse sputtering method, a physical etching method, or the like.

  Next, as shown in FIG. 10C, a metal layer 113 such as aluminum or silver is formed over the entire surface of the transparent resin substrate 111 by a vacuum deposition method, a sputtering method, a CVD method, or the like.

  Next, the transparent substrate 111 is immersed in a solvent in which the masking layer 112 is soluble, for example, a solvent such as isopropyl alcohol if the masking layer 112 is a polystyrene layer, and the metal layer 113 deposited on the recess 111a is removed together with the masking layer 112. As shown in (d), only the metal layer 113 deposited on the convex portion 111b is left. At this time, it is preferable to cut the metal layer 113 between the concave portion 111a and the convex portion 111b by irradiating ultrasonic waves and vibrating by the ultrasonic waves.

  As described above, the metal grid 113 is formed only on the convex portion 111b on the surface of the transparent resin substrate 111, and the wire grid polarizer 110 having a structure in which the surface of the substrate 111 is exposed in the concave portion 111a is obtained. Patent Document 1 states that the wire grid polarizer 110 that is bright and excellent in polarization characteristics can be easily manufactured in this manner.

  Further, in Patent Document 2 described later, a wire grid polarizer is used without using a photolithography method by similarly depositing a metal material from an oblique direction using a transparent substrate having wave-shaped fine irregularities on the surface. A manufacturing method has been proposed.

  Further, in Patent Document 3 to be described later, a wire grid polarizer in which a plurality of linear concavo-convex structures are formed on the top of a transparent substrate, and a conductor is provided in contact with the upper surface and / or the side surface of the convex portion. Has been proposed. FIG. 11 is a cross-sectional view showing the structure of the wire grid polarizers 120a to 120c shown in FIGS.

  FIG. 11A shows a polarizing element 120a in which an upper conductor layer 124 and a side conductor layer 125a are connected from the upper surface of the convex portion 122 to a part of the side surface (upper portion). ) Shows the polarizing element 120b in which the side conductor layer 125b is formed only on a part (upper part) of the side surface of the convex part 122. Patent Document 3 states that the upper conductor layer 124 and the side conductor layer 125a of the polarizing element 120a are formed by depositing a conductor material from above the convex portion 122 by sputtering or CVD. Yes. Further, it is described that the polarizing element 120b is formed by forming the upper conductor layer 124 and the side conductor layer 125a in the same manner as the polarizing element 120a, and then removing the upper conductor layer 124 by polishing or the like.

  FIG. 11C shows a polarizing element 120 c in which a side conductor layer 125 c is formed on the entire side surface of the protrusion 122. In Patent Document 3, the side conductor layer 125c is formed by forming a conductor layer on the entire surface of the concavo-convex structure by electroless plating or the like, and then performing highly anisotropic anisotropic etching (for example, reactive ion etching). ) Is used to selectively remove the conductor layer deposited on the top surface of the convex portion 122 and the bottom surface of the concave portion 123.

  The gist of Patent Document 3 is that a wire grid polarizer is constituted by a conductor layer having a principal surface in a direction orthogonal to the surface of the transparent substrate 121, such as the side conductor layers 125b and 125c. The upper conductor layer 124 formed on the upper surface of the convex portion 122 is unnecessary and is regarded as an obstacle to lowering the transmittance of TM polarized light. Therefore, as in the case of the wire grid polarizers 120b and 120c, the upper conductor layer 124 formed during the manufacturing process is finally removed by polishing or anisotropic etching in principle. . Even when the upper conductor layer 124 is left as in the wire grid polarizer 120a, it does not mean to use the upper conductor layer 124 as the conductor layer constituting the polarizer, but saves time and effort to remove it. It ’s just that. In fact, Patent Document 3 states that the insertion loss of the polarizing element 120b is improved by removing the upper conductor layer 124 compared to the polarizing element 120a. There is no description of optimizing the width of the upper conductor layer 124. A similar wire grid polarizer is also proposed in Patent Document 4 described later.

JP 2006-47813 A (Page 4-7, FIG. 1) JP 2001-330728 A (pages 3 and 4; FIGS. 1-4) JP 2002-328222 A (pages 3-5, 7 and 8; FIGS. 9-11) JP 2008-145581 A (page 6-8, FIG. 1)

  As described above, a lithography method and an etching method are usually used for manufacturing a grid structure such as a wire grid polarizer. In this case, high processing accuracy is required to produce a grid structure having a high aspect ratio. The larger the aspect ratio, the greater the in-plane processing variation that occurs during manufacturing, and the longer the processing time is required. This causes problems such as the production cost.

  In addition, the semiconductor process used for manufacturing the semiconductor element is limited to a substrate size that can be applied to the same size as a wafer. Therefore, the semiconductor process cannot cope with the production of a grid structure having a large area exceeding the wafer size.

  Patent Documents 1 to 4 propose a method of forming a wire grid polarizer using a transparent substrate having a plurality of linear fine concavo-convex structures formed on the surface. In particular, Patent Documents 1, 2, and 4 are noted in that a wire grid polarizer is formed without using a fine processing method such as a photolithography method. However, as in Patent Documents 1 and 2, when the grid structure is formed on a substrate having a wave-shaped uneven structure, the application range is extremely limited. In addition, a grid structure having a high aspect ratio cannot be produced.

  In Patent Documents 3 and 4, a conductor layer having a main surface in a direction perpendicular to the surface of the transparent substrate is formed by depositing a thin film conductor on the concave and convex side surfaces of the concave-convex structure having a rectangular cross section. However, an example is shown in which a wire grid polarizer is configured using this as a thin metal wire. This method has an advantage that a thin metal wire having a high aspect ratio can be easily formed. However, since the film thickness of the conductor layer is the width of the fine metal wires constituting the wire grid polarizer, to increase the width of the fine metal wires, the film thickness when forming the conductor layer is increased. However, the design of the wire grid polarizer is limited by the film thickness that can be formed.

  On the other hand, in Patent Documents 3 and 4, the upper conductor layer formed on the upper surface of the convex portion in the course of the manufacturing process is regarded as useless, and it is a rule that it is troublesome to remove it. Patent Documents 3 and 4 do not show the intention or proposal to use the upper conductor layer as the conductor layer constituting the polarizer. For this reason, a step of forming a conductor layer having a uniform thickness on the concavo-convex structure and a step of selectively removing the conductor layer formed above the convex portion and the bottom surface of the concave portion are necessary, and there are many manufacturing steps. Cost increases due to complexity. In addition, since the variation in the film quality and thickness of the conductor layer when forming the conductor layer and the variation in selectively removing a part of the conductor layer are doubled, the uniformity of the grid structure is improved. descend. In particular, when forming a large area grid structure, it becomes difficult to ensure uniformity.

  The present invention has been made in view of such circumstances, and the object thereof is to provide a grid structure having a high aspect ratio and a shape applicable to various purposes, and the grid structure can be easily manufactured. And it is providing the manufacturing method of the grid structure which can be produced even if the grid structure is the magnitude | size exceeding a wafer size.

That is, the present invention
A substrate having a surface structure in which a plurality of thin linear protrusions are arranged in parallel with each other at a constant pitch;
A thin linear upper functional material layer disposed on the upper surface of the convex portion;
Thin linear side functionalities that are arranged on the entire side surface and lateral sides of the convex portion so as to be connected to the upper functional material layer and constitute a thin linear functional member together with the upper functional material layer. The functional grid structure includes a material layer, and the base body is substantially exposed on the bottom surface of the concave portion between the adjacent convex portions.

Also,
Forming a surface structure in which a plurality of thin linear protrusions are arranged in parallel with each other at a constant pitch on the surface of the substrate;
Forming a thin linear upper functional material layer and a side functional material layer on the upper surface, the entire side surface, and the sides of the convex portion, respectively, and a method for producing a functional grid structure. It is related.

  In the functional grid structure of the present invention, a plurality of thin linear protrusions are formed on the surface of the base so as to be arranged in parallel with each other at a constant pitch. Further, not only a thin linear upper functional material layer is disposed on the upper surface of the convex portion, but also a thin straight line connected to the upper functional material layer on the entire side surface and the side of the convex portion. A side functional material layer is arranged, and a functional member is constituted by these layers. The functional member is merely a thin layer that does not have a content and covers the upper surface and side surfaces of the convex portion, but effectively functions in the same manner as a functional member that is filled with the content.

  The effective width of the functional member is a size obtained by adding the film thickness of the two side functional material layers formed to protrude laterally to the width of the convex portion. Further, the effective thickness of the functional member is a size obtained by adding the film thickness of the upper functional material layer to the thickness of the convex portion in the direction perpendicular to the surface of the substrate. And the said functional member can be produced much more easily than the functional member with the same width and thickness as this. Therefore, in the functional grid structure of the present invention, the functional member having a large effective thickness can be produced, and a space region having a large thickness sandwiched between these functional members adjacent to each other is formed as described above. It can be used as a spatial region in which the function of the functional member is expressed.

  Moreover, in the functional grid structure of the present invention, the dimensions of the functional member are the pitch, width, and thickness of the convex portions formed in advance, the upper functional material layer, and the side functional material. Since it is determined by the film forming conditions such as the film thickness of the layer, a fine processing method such as photolithography is not necessary when forming the functional member.

  The manufacturing method of the functional grid structure of the present invention includes a process for manufacturing the functional grid structure of the present invention, and the pitch, width, and thickness of the projections to be formed in advance, and the upper functionality. The dimensions of the functional member can be determined by the film formation conditions such as the film thickness of the material layer and the side functional material layer. For this reason, when the functional member is formed, only the film forming process needs to be performed, and a fine processing process requiring a large facility such as a photolithography means is unnecessary. Therefore, the functional grid structure of the present invention can be manufactured easily, with high productivity and at low cost, even if the size exceeds the wafer size, to which a microfabrication method such as photolithography cannot be applied.

  In the functional grid structure of the present invention, it is preferable that the surface structure of the base is made of a material different from a material constituting a main part of the base. By using different materials for the surface structure of the base and the main part, the functional grid structure of the present invention can be manufactured using the main part of various materials. For example, if an organic resin film is used as the main part of the substrate, a lightweight, flexible, and impact-resistant functional grid structure can be manufactured. In addition, if UV curable resin or thermoplastic resin is used as the material for the convex part and the concavo-convex structure formed on the mold is transferred by the nanoimprint method, it can be easily produced without using fine processing techniques such as photolithography. A convex part can be formed with good properties.

  Moreover, it is good to comprise as an optical element. For example, the upper functional material layer and the side functional material layer may be composed of metal layers, and may be configured as a wire grid diffraction grating in which light is reflected by these metal layers.

  At this time, the material constituting the upper metal layer and the side metal layer is preferably a material that easily reflects light, such as aluminum or silver. However, when film formation is performed using pure aluminum, the particle size of the film formation particles becomes as large as several tens of nanometers. It may cause film quality to change from place to place. Such variation reduces the light reflectivity of the aluminum film.

  In such a case, it is preferable to use an alloy to which a small amount of additive is added. For example, by using a material in which a small amount (for example, 0.5 to 1% by mass) of silicon and / or copper is added to aluminum, the particle size of the film-forming particles is reduced, and the irregularities generated at the line edge of the fine metal wire In addition, it is possible to suppress a change in the film quality of the aluminum film for each location and to increase the light reflectance of the aluminum film. In addition, when silver is used as a constituent material, if a similar phenomenon occurs, a material obtained by adding a trace amount (for example, 0.5 to 1% by mass) of palladium and / or copper to silver is used. It is effective. Even when another metal is used as a constituent material, it is desirable to use a material to which a small amount of another material is added in order to suppress generation of large film-forming particles.

  The upper functional material layer and the side functional material layer may be formed of a metal layer and configured as an electrode assembly.

  In the method for producing a functional grid structure according to the present invention, the upper surface and the lateral sides of the protrusions from a predetermined direction inclined by a predetermined angle θ from the direction perpendicular to the surface of the base to the arrangement direction of the protrusions. The upper functional material layer and the side functional material layer are formed without substantially depositing the functional material on the bottom surface of the concave portion between the adjacent convex portions. It is good.

  At this time, after a film is formed for a predetermined period from the predetermined direction, a series of steps for forming the film for a predetermined period from a direction symmetrical to the predetermined direction with respect to the direction perpendicular to the surface is repeated as many times as necessary. Is good. Further, it is preferable that the predetermined angle θ is gradually reduced in response to an increase in thickness of the upper functional material layer and the side functional material layer.

  Alternatively, after the functional material is deposited on the surface of the base body, the functional material deposited on the bottom surface of the concave portion between the adjacent convex portions is removed by etching back, and the convex portion The upper functional material layer and the side functional material layer may be formed while leaving a part of the functional material deposited on the upper surface and the side.

  Further, it is preferable that the convex portion is formed on the surface of the base body with a material different from a material constituting the main part of the base body.

On this occasion,
Producing a mold having a concavo-convex pattern;
A step of pressing the mold against a constituent material of the convex portion and transferring the concave / convex pattern to form the convex portion.

For more information,
Disposing a resin layer as a constituent material of the convex portion on the surface of the base;
Pressing the mold against the resin layer, and molding the resin layer in a shape complementary to the concavo-convex pattern;
A step of curing the resin layer during the molding and / or after the molding to form the convex portions;
A step of peeling the mold.

  At this time, an ultraviolet curable resin layer is disposed as the resin layer by a coating method or a printing method, and after molding with an ultraviolet transmissive mold, the ultraviolet curable resin layer is cured by irradiating ultraviolet rays through the mold. Good.

  Next, a preferred embodiment of the present invention will be described specifically and in detail with reference to the drawings.

Embodiment 1
In the first embodiment, mainly as an example of the functional grid structure described in claims 1 and 3 to 5 and the method for manufacturing the functional grid structure described in claims 7 to 10, a wire grid diffraction grating and The manufacturing method will be described.

  FIG. 1 is a cross-sectional view and a partially enlarged view showing a structure of a wire grid diffraction grating 10 based on the first embodiment. In the wire grid diffraction grating 10, a plurality of thin linear protrusions 2 are formed in parallel with each other at a constant pitch P on the surface of the light-transmitting support 1 that is the base. In this example, the light-transmissive support 1 and the convex portion 2 are made of the same material. For example, the convex portion 2 is formed on the surface of a glass plate by photolithography and reactive ion etching.

  A thin linear upper metal layer 4 is disposed on the upper surface of the convex portion 2, and the thin linear side metal layer 5 is connected to the upper metal layer 4 on the entire side surface and the side of the convex portion 2. Has been placed. The upper metal layer 4 and the side metal layer 5 constitute a thin metal wire 6 to form a wire grid diffraction grating 10. The upper metal layer 4, the side metal layer 5, and the fine metal wire 6 correspond to the upper functional material layer, the side functional material layer, and the functional member, respectively. The upper metal layer 4 and the side metal layer 5 are formed by depositing a metal material by an evaporation method or a sputtering method from an oblique direction. The metal material is preferably a material that easily reflects light, such as aluminum or silver. However, when film formation is performed using pure aluminum or pure silver, if the particle diameter of the film formation particle becomes too large, as described above, a small amount of silicon and / or copper (for example, , 0.5 to 1% by mass), and a small amount of palladium and / or copper (for example, 0.5 to 1% by mass) is added to silver.

  The thin metal wire 6 is not a true thin metal wire, and the substance is merely a thin metal layer covering the upper surface and the side surface of the convex portion 2. However, the present inventor has found that the metal fine wire 6 without the content can constitute the wire grid diffraction grating 10 in the same manner as the true metal fine wire with the content (see Japanese Patent Application No. 2008-291932). The fact that the contents of the fine metal wires constituting the wire grid diffraction grating 10 do not have to be clogged is natural considering that the interaction between the metal and light is caused by the action of free electrons occupying the surface of the metal. it is conceivable that. Accordingly, it is sufficient that the upper metal layer 4 and the side metal layer 5 have a thickness that does not transmit light. Here, various quantities that determine the performance of the wire grid diffraction grating 10 are examined on the assumption that the fine metal wires 6 can be considered in the same manner as the filled fine metal wires. Hereinafter, in order to simplify the description, a case where incident light is incident on the surface of the light-transmissive support 1 perpendicularly will be considered.

As is apparent from FIG. 1, the pitch of the fine metal wires 6 is the same as the pitch P of the protrusions 2 arranged. Further, as shown in the partial enlarged view, the effective width W of the fine metal wire 6 is the film thickness Ts of the two side metal layers 5 formed so as to protrude laterally to the width Wg of the convex portion 2. It becomes the size which added.
W = Wg + 2Ts
Further, the effective thickness T of the fine metal wire 6 is the thickness of the fine metal wire 6 that is felt in the transmission direction when light passes between the fine metal wires 6. From the partially enlarged view, this is equal to the thickness of the side metal layer 5 in the light transmission direction. However, even if it is the thickness of the side metal layer 5, the substance is the width which the side metal layer 5 occupies in the light transmission direction. As shown in FIG. 1, since the side metal layer 5 is provided on the entire side surface of the convex portion 2 and on the side of the upper metal layer 4, the effective thickness T of the fine metal wire 6 is determined in the light transmission direction. This is a size obtained by adding the film thickness Tu of the upper metal layer 4 to the thickness of the convex portion (the height of the convex portion 2 with respect to the bottom surface of the concave portion 3) Tg.
T = Tg + Tu

  As described above, in the wire grid diffraction grating 10, the effective thickness T of the fine metal wire 6 is a size obtained by adding the thickness Tg of the convex portion 2 in the light transmission direction to the thickness Tu of the upper metal layer 4. Become. Therefore, as in the conventional wire grid polarizer 100 shown in FIG. 9, the thickness of the convex portion 2 is larger than that of an element that realizes the thickness T of the thin metal wire 102 in the light transmission direction only by the thickness of the metal layer. The film thickness Tu of the upper metal layer 4 can be reduced by the thickness Tg, and can be easily manufactured. At this time, since the side metal layer 5 is formed on the entire side surface of the convex portion 2, the convex portion 122 is formed like a wire grid polarizer 120 a (see FIG. 11A) proposed in Patent Document 3. Compared with the element in which the side conductor layer 125a is formed only on a part (upper part) of the side surface, the side surface of the convex portion 2 can be used more effectively. Moreover, compared with the element (refer FIG.11 (c)) which implement | achieves a metal fine wire only by a side metal layer like the wire grid polarizer proposed by patent document 3 or 4, the upper metal layer 4 is sufficient. Since the thickness Tg of the convex portion 2 can be reduced by the film thickness Tu, the convex portion 2 can be easily manufactured.

  Moreover, since the width W of the thin metal wire 6 is the sum of the width Wg of the convex portion 2 and the film thickness Ts of the two side metal layers 5, the width Wg of the convex portion 2 should be appropriately selected. Thus, the width W of the thin metal wire 6 can be set to a predetermined size independently of the film thickness Ts of the side metal layer 5. Accordingly, the wire grid diffraction grating 10 is an element (such as a wire grid polarizer proposed in Patent Document 3 or 4) in which the width of the fine metal wire is determined to be the same as the film thickness of the side metal layer (see FIG. 11 (c)), the degree of freedom of design is much greater and the fabrication becomes easier.

  In addition, various quantities that determine the performance of the wire grid diffraction grating 10 are the pitch P, width Wg, and thickness Tg of the protrusions 2 formed in advance, the film thickness Tu of the upper metal layer 4 and the side metal. Since it is determined by the film forming conditions such as the film thickness Ts of the layer 5, a fine processing method such as lithography is not necessary when forming the thin metal wire 6. Therefore, even if the size exceeds the wafer size, it can be manufactured. In addition, by reducing the film thickness of the upper metal layer 4 and the side metal layer 5, it is possible to reduce the film formation time and the film thickness variation, leading to an improvement in yield.

  FIG. 2 is a cross-sectional view showing a flow of a manufacturing process of the wire grid diffraction grating 10.

  First, as shown in FIG. 2A, a light transmissive support 1 is prepared. The light transmissive support 1 is a glass plate or an organic resin plate. A surface structure in which a plurality of thin linear protrusions 2 are arranged in parallel with each other at a constant pitch P is formed on this surface by, for example, photolithography and reactive ion etching.

  Next, as shown in FIG. 2 (b), by depositing a metal material by an evaporation method or a sputtering method from an oblique direction, an upper portion is selectively formed on the upper surface of the convex portion 2 and the entire side surface and one side surface. The metal layer 4 and the side metal layer 5a are formed.

The vapor deposition source or target that emits the metal material is arranged in a direction inclined by a predetermined angle θ from the direction perpendicular to the surface of the light transmissive support 1 to the arrangement direction of the convex portions 2. The angle θ is an angle at which the bottom surface of the concave portion 3 between the adjacent convex portions 2 just fits in the shadow created by the convex portion 2 and no metal material is deposited on the bottom surface of the concave portion 3. In other words, the vapor deposition source or the target is arranged in a direction in which the upper end corner B of the adjacent convex portion 2 is looked up from the position A of the boundary between the lowermost portion of the convex portion 2 and the concave portion 3. That is, the angle θ is expressed by the following equation: θ = arc tan ((P−Wg) / Tg)
Given in.

  When the angle is larger than θ, a region where no metal material is deposited is generated at the lowermost portion of the convex portion 2. Conversely, when the angle is smaller than θ, the metal material is deposited on a part of the bottom surface of the recess 3. By setting the angle to θ, a thin linear upper metal layer 4 is selectively formed on the upper surface and one side surface of the convex portion 2 without substantially depositing a metal material on the bottom surface of the concave portion 3. The side metal layer 5a can be formed.

  In actual film formation, film-forming particles that behave in an unthinkable manner due to scattering or the like appear. In order to cope with such a complicated phenomenon, several prototypes of wire grid diffraction gratings 10 formed by changing the angle slightly before and after the predetermined angle θ are fabricated, and concave portions are formed by transmission electron microscope (TEM) analysis of a cross section. It is desirable to observe the state of deposition of the metal material on No. 3 and select a film forming angle at which a characteristic closest to the desired characteristic is obtained. Note that “substantially do not deposit metal material on the bottom surface of the recess 3” means that “a small amount of metal material is deposited on the bottom surface of the recess 3 due to scattering, etc.” "There is not enough deposition to prevent light transmission and essentially change the performance of the wire grid grating 10".

  After the film is formed for a predetermined period from the predetermined direction as described above, the film is formed for a predetermined period from a direction symmetrical to the predetermined direction with respect to the direction perpendicular to the surface as shown in FIG. In this manner, the thin linear upper metal layer 4 and the side metal layer 5b are selectively formed on the upper surface of the convex portion 2 and one side surface on the opposite side.

  Thereafter, the series of steps shown in FIGS. 2B and 2C are repeated as many times as necessary, and a metal material is substantially deposited on the bottom surface of the recess 3 as shown in FIG. 2D. Without being formed, a thin linear upper metal layer 4 and side metal layer 5 are selectively formed on the upper surface and both sides of the convex portion 2, respectively.

  At this time, on the side surface in the vicinity of the lowermost portion of the convex portion 2, as film formation proceeds, the upper metal layer 4 and the side metal layer 5 are increased as the film thickness of the upper metal layer 4 and the side metal layer 5 increases. The area where the metal material does not enter gradually becomes larger. Of the film thickness of the side metal layer 5, the film thickness of the side metal layer 5 formed on the side surface in the vicinity of the lowermost portion of the convex portion 2 is compared with the film thickness of the side metal layer 5 formed on the upper side surface. This is why it is small. In order to reduce the influence of the shadow produced by the upper metal layer 4, the film forming angle is gradually reduced from the initial value corresponding to the increase in the film thickness of the upper metal layer 4 and the side metal layer 5. Is good.

  As shown in the enlarged view of FIG. 1, when the film is formed from an oblique direction, the side metal layer 5 is formed. Therefore, the width W of the thin metal wire 6 is equal to the film thickness of the two side metal layers 5. Only 2Ts becomes larger than the width Wg of the convex part 2 (W = Wg + 2Ts). Accordingly, the width Wg of the convex portion 2 is set in consideration of the film thickness Ts of the side metal layer 5 so that a necessary gap remains between the fine metal wires 6 after film formation (Wg = W−2Ts).

The following relationship exists between the film thickness Tu of the upper metal layer 4 and the film thickness Ts of the side metal layer 5.
Ts = Tu × tanθ
If an attempt is made to increase the film thickness Tu of the upper metal layer 4 under a constant θ, the film thickness Ts of the side metal layer 5 also increases accordingly, and as a result, it is necessary to further reduce the width Wg of the protrusion 2. It may become difficult to form the convex portion 2. In such a case, it is preferable to make the height Tg of the convex portion 2 as large as possible. In this way, since the film forming angle θ can be reduced, the metal material deposited on the side of the convex portion 2 can be reduced, and the upper portion of the side metal layer 5 can be reduced while keeping the film thickness Ts small. The film thickness Tu of the metal layer 4 can be increased.

  FIG. 3 is an explanatory view showing a film forming method used in the manufacturing process of the wire grid diffraction grating 10. FIG. 3A corresponds to FIGS. 2B and 2C and shows a method of changing the film forming angle by changing the tilt angle of the light-transmissive support 1. FIG. 3B shows a method of setting the film formation angle by controlling the movement direction of the film formation particles by the collimator 12. According to this method, the side metal layer 5a and the side metal layer 5b can be simultaneously formed on both side surfaces of the convex portion 2, respectively.

  FIG. 4 is another explanatory view showing a film forming method used in the manufacturing process of the wire grid diffraction grating 10. As described above, when the film formation proceeds, the upper metal layer 4 and the side portion are formed on the side surfaces near the bottom of the convex portion 2 as the film thicknesses of the upper metal layer 4 and the side metal layer 5 increase. The region where the metal layer 5 enters the shadow and the metal material does not enter gradually increases. In order to reduce this influence, it is preferable to gradually decrease the film formation angle from the initial value in accordance with the increase in the film thickness of the upper metal layer 4 and the side metal layer 5. FIG. 4 shows changes at that time, and the film formation angle is changed from θa → θb → θc → θd → along with the progress of film formation (a) → (b) → (c) → (d) → (e). It is shown that θe (θa> θb> θc> θd> θe) is changed.

  As described above, in the method of manufacturing the wire grid diffraction grating 10 according to the present embodiment, the pitch, width Wg, and thickness Tg of the protrusions 2 to be formed in advance and the film thickness Tu on the side of the upper metal layer 4 are increased. Various quantities governing the specifications of the wire grid diffraction grating can be determined by the film formation conditions such as the film thickness Ts of the partial metal layer 5 and the film formation angle θ. In particular, when the upper metal layer 4 and the side metal layer 5 are formed, only the film forming process needs to be performed, and a fine processing process such as photolithography is unnecessary. Therefore, the wire grid diffraction grating 10 can be manufactured easily, with high productivity, and at low cost, even if the size exceeds the wafer size, to which a fine processing method such as photolithography cannot be applied.

Embodiment 2
In the second embodiment, mainly as an example of the functional grid structure described in claim 2 and the method of manufacturing the functional grid structure described in claims 12 to 15, a wire grid diffraction grating and a method of manufacturing the same are described. An example will be described.

  FIG. 5 is a sectional view showing a structure of a wire grid diffraction grating based on the second embodiment. In the wire grid polarizers 20a and 20b, the convex portion of the light transmissive support is formed of a material different from the material constituting the main portion 21 of the light transmissive support. FIG. 5A shows an example in which only the convex portion 22 is made of a different material, and FIG. 5B shows an example in which the upper portion 23 and the convex portion 24 of the light-transmitting support are made of different materials. .

  As in these examples, by using different materials for the main portion 21 of the light-transmitting support and the convex portions 22 or 24, the light-transmitting support main portion 21 of various materials can be used to form a wire grid diffraction grating. 20a or 20b can be formed. For example, if an organic resin film is used as the light transmissive support main part 21, a light, flexible, and impact resistant wire grid diffraction grating can be produced.

  Further, if an ultraviolet curable resin or a thermoplastic resin is used as a constituent material of the convex portion 22 or 24 and the concave / convex structure formed on the mold is transferred by the nanoimprint method, the microfabrication such as photolithography can be easily performed with high productivity. The convex portions 22 or 24 can be formed without using a technique.

  FIG. 6 is a cross-sectional view showing a part of a flow of a manufacturing process of the wire grid diffraction grating based on the second embodiment. In this example, the convex portion 22 is formed by a nanoimprint method.

  First, a mold 63 having a concavo-convex pattern formed separately as shown in FIG. The method for producing the mold 63 is not limited, but is formed by, for example, photolithography and reactive ion etching. On the other hand, a resin layer 61 is disposed as a constituent material of the convex portion 22 on the surface of the light transmissive support main body 21. As the resin layer 61, for example, an ultraviolet curable resin layer is formed by a coating method or a printing method.

  Next, as shown in FIG. 6B, a mold 63 is pressed against the resin layer 61 to form a resin layer 62 that is shaped so as to be concavo-convexly fitted to the concavo-convex pattern of the mold 63.

  Then, during and / or after molding, the resin material is cured to form the convex portions 22. At this time, when an ultraviolet curable resin is used as the resin material, as shown in FIG. 6C, after being molded by an ultraviolet transmissive mold 63, ultraviolet rays having a wavelength of about 300 to 400 nm are irradiated through the mold 63. Thus, the ultraviolet curable resin layer is preferably cured. As the ultraviolet curable resin, for example, an acrylate-based or epoxy-based ultraviolet curable resin can be used. When an ultraviolet curable resin is used, since the curing process is performed at room temperature, there is an advantage that there is no change in dimensions due to a temperature change.

  When a thermoplastic resin is used as the resin material, the resin layer 61 is heated to a temperature equal to or higher than the glass transition temperature before the mold 63 is pressed to soften the thermoplastic resin, and the mold 63 is pressed in this state. Then, after cooling and curing to a temperature below the glass transition temperature, the mold 63 is peeled off. As the thermoplastic resin, for example, polymethyl methacrylate (PMMA) resin or polycarbonate (PC) resin is used.

  Since the mold 63 can be used over and over again, the mold 63 may be smaller than the light transmissive support main body 21. Therefore, it can be precisely manufactured using a semiconductor microfabrication technique. Further, if the mold 63 is formed into a roller shape having a concavo-convex pattern formed on the outer peripheral surface, the concavo-convex pattern can be transferred by pressing the roller-shaped mold 63 against the resin layer 61 while rotating. The convex part 22 can be efficiently formed even for the light-transmitting support main part 21 having an area.

  In addition, since the upper metal layer 4 and the side metal layer 5 and the manufacturing method thereof are the same as those of the wire grid diffraction grating 10 based on the first embodiment, they are not duplicated and will not be described.

Embodiment 3
In the third embodiment, an example of a wire grid diffraction grating manufactured by the method for manufacturing a functional grid structure according to claim 11 and an example of a wire grid diffraction grating corresponding to a modification of the first embodiment will be described. To do.

  FIG. 7 is a sectional view showing a structure of a wire grid diffraction grating based on the third embodiment. The wire grid diffraction gratings 30 and 40 shown in FIG. 7 (a) and FIG. 7 (b), respectively, are implemented by the fact that side metal layers 35 and 45 having a substantially constant film thickness are formed on the side surfaces of the convex portion 2. The same function as that of the wire grid diffraction grating 10 can be obtained only by being different from the wire grid diffraction grating 10 based on the first embodiment. The wire grid diffraction gratings 30 and 40 are formed by depositing a metal material on the entire surface of the light-transmitting support 1 provided with the projections 2 and then etching back to thereby deposit the metal material deposited on the bottom surface of the recesses 3. The upper metal layer 4 and the side metal layer 35 or 45 can be obtained by removing and leaving a part of the metal material deposited on the upper surface and the side of the convex portion 2. As a method for depositing the metal material, a CVD method capable of forming a film with small anisotropy is preferable.

Embodiment 4
In the fourth embodiment, as an example of the functional grid structure described in claim 6, functionality obtained by filling another functional member in a space region sandwiched between the adjacent side functional material layers. An example of the element will be described.

  FIG. 8A is a cross-sectional view showing an example in which a color filter 77 composed of a functional grid structure 70 based on the fourth embodiment is formed. In the functional grid structure 70, a light-transmitting substrate 71 such as a glass substrate is provided with a convex portion 72, and a light-absorbing material made of a black carbon material or the like as the functional member on the upper surface and side of the convex portion 72. A layer 73 is formed. The concave portions of the functional grid structure 70 partitioned by the light absorbing material layer 73 are filled with color filter materials corresponding to the three primary colors of red, green, and blue to form a color filter 77.

  FIG. 8B is a cross-sectional view showing an example in which a light emitting element assembly 86 composed of the functional grid structure 80 based on the fourth embodiment is formed. In the functional grid structure 80, a convex portion 82 is provided on a light reflective substrate 81, and electrodes 83 and 84 made of metal or the like are formed as the functional member on the upper surface and the side of the convex portion 82. Then, the light emitting material 85 is filled in the concave portions of the functional grid structure 80 partitioned by the electrodes 83 and 84 to form a light emitting element assembly 86. The electrodes 83 and 84 are alternately arranged and used as an anode and a cathode.

  As mentioned above, although this invention was demonstrated based on embodiment, it cannot be overemphasized that this invention is not limited to these examples at all, and can be suitably changed in the range which does not deviate from the main point of invention.

  The functional grid structure and the manufacturing method thereof according to the present invention can be used as an optical member or an electrode assembly, and can be conventionally manufactured because a large diffraction grating that cannot be manufactured conventionally can be manufactured at low cost. It can create new application fields.

It is sectional drawing and the elements on larger scale which show the structure of the wire grid diffraction grating based on Embodiment 1 of this invention. It is sectional drawing which shows the flow of the manufacturing process of a wire grid diffraction grating. It is explanatory drawing which shows the film-forming method used at the manufacturing process of a wire grid diffraction grating. It is another explanatory drawing which shows the film-forming method used at the manufacturing process of a wire grid diffraction grating. It is sectional drawing which shows the structure of the wire grid diffraction grating based on Embodiment 2 of this invention. It is sectional drawing which shows a part of flow of the manufacturing process of a wire grid diffraction grating. It is sectional drawing which shows the structure of the wire grid diffraction grating based on Embodiment 3 of this invention. It is sectional drawing which shows the structure of the functional element obtained from the functional grid structure based on Embodiment 4 of this invention. It is the perspective view and partial expanded sectional view which show the structure of the conventional basic wire grid polarizer. It is sectional drawing which shows the preparation process of the wire grid polarizer shown by patent document 1. FIG. It is sectional drawing which shows the structure of the wire grid polarizer shown by patent document 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light transmissive support body, 2 ... Convex part, 3 ... Concave part, 4 ... Upper metal layer,
5, 5a, 5b ... side metal layer, 6 ... fine metal wire, 10 ... wire grid diffraction grating,
11 ... evaporation source or target, 12 ... collimator,
20a, 20b ... wire grid diffraction grating, 21 ... light transmissive support main part, 22 ... convex part,
23: upper part of light-transmitting support, 24: convex part, 30, 40 ... wire grid diffraction grating,
35, 45 ... side metal layer, 61 ... resin layer, 62 ... molded resin layer, 63 ... mold,
70 ... Functional grid structure, 71 ... Light transmissive substrate, 72 ... Projection,
73: Light absorbing material layer, 74: Color filter material (red),
75 ... Color filter material (green), 76 ... Color filter material (blue),
77 ... color filter, 80 ... functional grid structure, 81 ... light reflective substrate,
82 ... convex part, 83 ... electrode (anode), 84 ... electrode (cathode), 85 ... luminescent material,
86 ... Light-emitting element assembly, 100 ... Wire grid polarizer, 101 ... Transparent substrate,
102 ... Fine metal wire, 110 ... Wire grid polarizer, 111 ... Transparent resin substrate,
111a ... concave, 111b ... convex, 112 ... masking layer, 113 ... metal layer,
120a-120c ... wire grid polarizer, 121 ... transparent substrate, 122 ... convex part,
123: Recess, 124 ... Upper conductor layer, 125a to 125c ... Side conductor layer,
P: pitch of fine metal wires, W: width of fine metal wires, T: thickness of fine metal wires

Claims (15)

A substrate having a surface structure in which a plurality of thin linear protrusions are arranged in parallel with each other at a constant pitch;
A thin linear upper functional material layer disposed on the upper surface of the convex portion;
Thin linear side functionalities that are arranged on the entire side surface and lateral sides of the convex portion so as to be connected to the upper functional material layer and constitute a thin linear functional member together with the upper functional material layer. A functional grid structure comprising a material layer, wherein the base body is substantially exposed on the bottom surface of the concave portion between the adjacent convex portions.   The functional grid structure according to claim 1, wherein the surface structure of the base is formed of a material different from a material constituting a main part of the base.   The functional grid structure according to claim 1, which is configured as an optical element.   The functionality according to claim 3, wherein the upper functional material layer and the side functional material layer are composed of metal layers, and are configured as a wire functional grid diffraction grating in which light is reflected by these metal layers. Grid structure.   The functional grid structure according to claim 4, wherein the material of the metal layer is aluminum Al, silver Ag, or an alloy obtained by adding a small amount of additives to these metals.   The functional grid structure according to claim 1, wherein the upper functional material layer and the side functional material layer are made of a metal layer and configured as an electrode assembly. Forming a surface structure in which a plurality of thin linear protrusions are arranged in parallel with each other at a constant pitch on the surface of the substrate;
Forming a thin linear upper functional material layer and a side functional material layer on the upper surface, the entire side surface, and the sides of the convex portion, respectively.   By depositing a functional material from a predetermined direction inclined by a predetermined angle θ from the direction perpendicular to the front surface of the base to the arrangement direction of the convex portions from the upper surface and the side of the convex portions, The functional grid structure according to claim 7, wherein the upper functional material layer and the side functional material layer are formed without substantially depositing a functional material on the bottom surface of the concave portion between the convex portions. Production method.   9. A series of steps of forming a film for a predetermined period from a direction symmetrical to the predetermined direction with respect to a direction perpendicular to the surface of the previous period after forming the film for a predetermined period from the predetermined direction is repeated as many times as necessary. The manufacturing method of the functional grid structure described in 1 above.   The manufacturing of the functional grid structure according to claim 9, wherein the predetermined angle θ is gradually reduced in response to an increase in thickness of the upper functional material layer and the side functional material layer. Method.   After the functional material is deposited on the front surface of the base body, the functional material deposited on the bottom surface of the concave portion between the adjacent convex portions is removed by etching back, and the top surface and the side of the convex portion are removed. The method for producing a functional grid structure according to claim 7, wherein the upper functional material layer and the side functional material layer are formed while leaving a part of the functional material deposited in the first direction.   The method for manufacturing a functional grid structure according to claim 7, wherein the convex portion is formed on the surface of the base body with a material different from a material constituting the main part of the base body. Producing a mold having a concavo-convex pattern;
The method for manufacturing a functional grid structure according to claim 12, further comprising: pressing the mold against a constituent material of the convex portion to transfer the concave / convex pattern to form the convex portion. Disposing a resin layer as a constituent material of the convex portion on the surface of the main portion of the base;
Pressing the mold against the resin layer, and molding the resin layer in a shape complementary to the concavo-convex pattern;
A step of curing the resin layer during the molding and / or after the molding to form the first convex portion;
The method for producing a functional grid structure according to claim 13, further comprising a step of peeling the mold in the previous period.   The ultraviolet curable resin layer is disposed as a resin layer by a coating method or a printing method, and is molded by an ultraviolet transmissive mold, and then the ultraviolet curable resin layer is cured by irradiating ultraviolet rays through the mold. A method for manufacturing the described functional grid structure.

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