JP2002113724A - Microstructure array and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microstructure array capable of being reduced in its in-plane distribution and capable of being easily manufactured relatively inexpensively, and a method for manufacturing the same. SOLUTION: The microstructure array 9 is manufactured by forming a mask layer 6 on the flat surface of a substrate 5 and forming a plurality of aperture parts 7 in the mask layer 6, and the substrate 5 in etched through the aperture parts 7 to form the substrate 5 having fine projections and removing the mask layer 6 to form a precipitation layer 6 on the substrate 5 using a chemical precipitation method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens array used in the field of optoelectronics and the like, and a mold for producing the same (herein, the term "mold" is used unless otherwise specified). The present invention relates to a microstructure array such as a mold and a mold master), a method of manufacturing the same, and the like.

[0002]

2. Description of the Related Art A microlens array has a plurality of microscopic substantially hemispherical lenses each having a diameter of several μm to several hundreds of μm. It has come to be used for applications.

On the other hand, the development of surface emitting lasers and the like, in which the interval between light emitting elements can be narrowed and which can be easily arrayed, has been advanced, and the demand for microlenses having a large numerical aperture (NA) which can narrow the interval between lens arrays has been increasing.

[0004] Similarly, with the development of semiconductor process technology, the distance between the elements has been narrowed, and the size of the light receiving elements has been increasingly reduced as seen in CCDs and the like. As a result, here too, a microlens array with a small lens spacing and a large numerical aperture is required.

[0005] Further, there is a similar demand in optical parallel processing / calculation, optical interconnection and the like, which are expected fields of optical information processing in the future.

Further, electroluminescence (EL)
Research and development of display devices such as those described above have been actively conducted, and high-definition and high-brightness liquid crystal displays have also been actively developed. In such a display, there is a demand for a low-cost, large-area microlens array that plays a role in improving luminance.

[0007]

Under the circumstances described above, the ion exchange method (M. Oikawa, et al., Jpn. J.
Appl. Phys. 20 (1) L51-54, 1981), a method of manufacturing a microlens array in which a plurality of portions on a substrate made of multi-component glass are made to have a high refractive index to form a plurality of lenses. Also, a method is known which utilizes the fact that the unexposed part is crystallized and the surface expands during the heat treatment of the photosensitive glass. However, in these methods, the aperture diameter of the lens cannot be made larger than the distance between the lenses, and it is difficult to design a lens having a large numerical aperture.

Further, a large-scale manufacturing apparatus is required to manufacture a large-area microlens array, and there is a problem that manufacturing is not easy. In addition, these methods
The substrate material is limited to glass, and the thermal expansion coefficient of the glass substrate itself is significantly different from the thermal expansion coefficient of the substrate of the light receiving device or light emitting device. Misalignment occurs.

As another method, a registry flow method (D. Daly, et al., Proc. MicrolensArrays Teddingto
n., p23-34, 1991). In this method, a resin formed on a substrate is patterned into a cylindrical shape using a photolithography process, and heated and reflowed to produce a microlens array. By this method, lenses of various shapes can be manufactured at low cost. Also, there are no problems such as thermal expansion coefficient and warpage as compared with the ion exchange method. Furthermore, by patterning and reflowing a resist directly on an element such as a surface emitting laser, a microlens array can be formed directly on the element, and an alignment step by joining the microlens array and the element can be omitted.

However, in this method, the shape of the microlens array strongly depends on the thickness of the resin, the wettability between the substrate and the resin, and the heating temperature, and the work reproducibility in a single substrate is high. In addition, variations among lots are likely to occur.

As another method, there is a method in which an original plate of a microlens array is produced, a lens material is applied to the original plate, and the applied lens material is peeled off. In preparing a mold serving as an original plate, a method of drawing using an electron beam (JP-A-1-261601) and a method of etching and forming a part of a metal plate (JP-A-5-303909)
Publication). According to these methods, the microlens can be duplicated by molding, the variation does not easily occur between lots, and it can be manufactured at low cost. Further, as compared with the ion exchange method, problems such as generation of an alignment error and warpage due to a difference in thermal expansion coefficient can be avoided. However, in the method using an electron beam,
Because the electron beam lithography system is expensive and requires a large amount of capital investment, and the drawing area is limited, 10 c
There is a problem that it is difficult to produce a master having a large area of m square or more.

In the etching method, when isotropic etching mainly using a chemical reaction is used, etching is continued unless water is washed immediately when a desired shape is obtained. When a minute microlens is formed, the shape may deviate from the desired shape due to etching that progresses from the time when the desired shape is obtained to the time of washing with water.

As still another method of manufacturing a mold, a method of manufacturing a mold using electroplating (Japanese Patent Laid-Open No. Sho 64-10169).
There is. This is to form fine projections on the substrate by any of machining method, photo etching method, electroplating method,
This is electroplated to grow the plating layer into a convex shape,
It is a method of using it as a mold. However, in electroplating, current usually concentrates at the end of the electrode,
It is difficult to deposit a metal of uniform thickness over a large area. Therefore, in the above manufacturing method, for example, FIG.
As shown in the figure, the current is concentrated at the periphery of the array pattern to promote plating growth, and the hemispherical structure 4 as a plating layer is formed.
May have an in-plane distribution. Further, depending on the shape of the fine projection, the radius of curvature of the convex shape of the plating layer 4 is not uniform. As a result, when the microlens array is duplicated using the original as a master, there is a possibility that a problem may occur in that the optical characteristic specifications of individual lenses vary.

As a method of manufacturing a microlens, a convex portion is formed on quartz glass, and a CVD method (Ch
There is a method of manufacturing a microlens by performing an emical vapor deposition method (Japanese Patent Application Laid-Open No. H11-119004). In this case, a flat surface exists on the top of a convex portion formed by etching. It is difficult to obtain a microlens obtained by performing CVD on the microlens having a uniform curvature depending on an initial convex shape.

The present invention has been made in view of the above-mentioned problems of the prior art, and has the following objects. (1) The in-plane distribution of microstructures can be reduced, (2) fabrication is easy, and 3) An object of the present invention is to provide a microlens array mold and a microstructure array such as a microlens array which can be manufactured relatively inexpensively, and a method for manufacturing the same.

[0016]

The method for fabricating a microstructure array according to the present invention, which achieves the above object, comprises the following steps: (1) forming a mask layer on a substrate surface (typically, a flat surface); (2) forming a plurality of openings in the mask layer,
(3) a step of forming a substrate having fine projections by etching the substrate from the opening, (4) a step of removing the mask layer, (5) using a chemical deposition method to form a deposited layer on the substrate. It is characterized by having a forming step. In this manufacturing method, the opening can be patterned in the mask layer with a flexible design, and the substrate can be etched to an appropriate degree through the opening by isotropic etching or the like. Also, a structure in which the in-plane distribution of the microstructure can be reduced can be manufactured relatively easily and relatively inexpensively with high controllability. Further, a microstructure having an aspherical surface or a non-cylindrical surface can be easily formed.

Based on the above basic configuration, the following more specific modes can be adopted. Etching in step (3)
Typically, it is an isotropic etching. This is an easy-to-control etching method because the etching shape is reliably and stably determined by controlling the etching time.

In the step (2), the opening has a circular shape, a slit shape or the like. In these cases, the etching shape in the step (3) becomes a hemispherical shape, a semicylindrical shape, or the like.

In the step (3), preferably, a flat surface is not included at the tip of the minute projection obtained by etching.
Thus, a deposition layer having a hemispherical or semi-cylindrical shape, a deposition layer having a hemispherical or semi-cylindrical shape, and an aspherical or non-cylindrical shape can be stably produced.

In the step (3), the etching is terminated at the time when the micro projections having no flat surface at the tip are obtained. The etching may be terminated after an appropriate amount of etching is continued. In the former case, in step (5), it can be ensured that the deposited layer formed on the substrate having the fine projections has a hemispherical or semicylindrical shape, and in the latter case,
It can be ensured that the deposited layer formed on the substrate having the fine projections has a hemispherical or semicylindrical shape and an aspherical or noncylindrical shape.

The deposited layer in the step (5) is formed by electroless plating in which the thickness can be easily controlled by controlling time and temperature, and the growth rate can be precisely controlled to control the curvature of the microstructure. Is formed by a chemical deposition method (CVD) that can easily and precisely control the temperature.

In the step (2), the shape and arrangement of the openings can be freely set according to the application. For example, they may all be formed in the same shape, or may be arranged regularly (for example, arranged at equal intervals in the left, right, up, and down directions).

The microstructure array may be a microstructure array mold such as a microlens array mold, or a microlens array.

Further, the microstructure array of the present invention that achieves the above object has a substrate having fine projections without a flat surface at the tip and a chemical deposition method formed on the substrate having the fine projections. And a precipitation layer comprising:

In order to make the microstructure array into a microlens array or the like, the substrate and the deposited layer formed by the chemical deposition method may be translucent.

The deposition layer typically has a hemispherical or semi-cylindrical shape, or has a hemispherical or semi-cylindrical shape and an aspherical or non-cylindrical shape formed at the base of the shape.

The above is the basic and more specific components of the present invention, and the details and operation thereof will be further described below along with typical examples.

A typical example of a method of manufacturing a microstructure array, which is typically a microlens array, and a mold therefor will be described. Here, a microlens or a microlens array refers to a microstructure as a representative. Of course, what is described here can also be applied to a method for manufacturing another mold for a microstructure array.

In the manufacturing method of the present invention, a fine or fine opening is formed in a mask layer provided on a substrate, and the substrate is etched isotropically from the opening to form a substrate having fine projections. A deposition layer formed by a chemical deposition method is formed thereon to obtain a structure having a hemispherical or semicylindrical shape (hereinafter, represented by a hemispherical structure).

When the isotropic etching is performed from the openings arranged in the mask layer in the substrate surface, the substrate is etched into a substantially hemispherical shape, and the central portion corresponding to the gap between the openings is finally left. Fig. 1 (c), Fig. 2 (c), Fig. 3
Fine projections are formed as shown in FIG. When this is subjected to electroless plating or CVD, as shown in FIGS. 8 and 9,
Since the deposited layer grows isotropically with respect to the shape of the substrate 5, the deposited layer formed by the chemical deposition method growing from the tip of the microprojection is shown in FIGS. 1 (f), 2 (f), 3 (f). ) Are hemispherical structures 9, 11, and 16.

In this case, even if each hemispherical structure is grown so as to be in contact with each other diagonally, isotropic growth proceeds,
A hemispherical structure having a uniform radius of curvature can be obtained. In addition, as shown in FIGS. 4, 5 and 6, by controlling the etching depth, the hemispherical structures 21, 23 and 28 can have asphericity.

In the isotropic etching, the curvature of the etching surface immediately below the opening is slightly smaller than the curvature of the etching side surface. However, in the present invention, a hemispherical structure is formed by forming a deposition layer on minute projections. Therefore, the curvature of the etched surface immediately below the opening does not affect the curvature of the formed hemispherical structure. Furthermore, in this case, since the tip of the microprojection is etched by isotropic etching from all sides, it is possible to almost eliminate the flat surface on the top of the projection, so that the microstructure 9 obtained from the tip is It has a substantially hemispherical shape.

In these cases, since both etching and chemical deposition proceed in-plane uniformly, a microlens array mold or a microlens array with little variation in the shape of the hemispherical structure can be obtained. Here, as the chemical deposition method, electroless plating, CVD, and the like can be used, but the method is not limited to these as long as the chemical deposition is possible.

As materials for the electroless plating, Ni, Cr, Au, A
g, Cu, Co, etc., and alloys thereof can be used. Thermal CVD, LP (Liquid Phase) -C
VD, plasma-CVD, and the like can be used, and by these methods, metal carbide, boride, nitride, oxide, and the like can be deposited.

In these cases, by forming a material having excellent corrosion resistance and abrasion resistance, such as Cr, on the surface of the deposited layer formed by the chemical deposition method, ie, a material excellent in mechanical and chemical properties, the corrosion resistance is improved. , Abrasion resistance and the like can be improved.

In the present invention, a method of manufacturing a microstructure array such as a microlens array mold using a deposition form of a deposition layer formed by the chemical deposition method, and a microlens manufactured by using the same A microstructure array such as an array mold is realized, but the shape of the microlens array produced by molding using the microlens array mold obtained by the present invention is the same as that of the deposited layer. It will be.
Further, in the present invention, when a light transmitting material is used for the substrate and the CVD deposition material, it can be directly used as a microlens array.

When the microlens array mold is manufactured using electroless plating, expensive equipment is not required.
It can be manufactured at low cost and can be easily enlarged. Further, in the case of using electroless plating, the amount of deposition can be controlled with high accuracy by temperature, time, and the like, so that the shape of the hemispherical structure can be arbitrarily controlled. Therefore, the microlens array manufactured from the mold obtained by the present invention can easily and accurately control the shape of the lens.

Even when the microlens array mold and the like are manufactured by CVD, since the amount of deposition can be controlled with high precision, the shape of the hemispherical structure can be arbitrarily controlled. Therefore,
A microlens array manufactured from a mold obtained by this method can also easily and accurately control the shape of a lens. Further, a hemispherical structure obtained by a combination of a light-transmitting substrate and CVD using a light-transmitting material as a source is directly used as a microlens, and the effect is the same as described above.

As described above, in the electroless plating, the thickness of the plating layer can be easily controlled by controlling the plating time and the plating temperature. For the types of electroless plating, Ni, Au, Ag, Cu, Co
And alloys such as Co-Fe, Co-W, Ni-Co, Ni-Fe, and Ni-W. Examples of the reducing agent include sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, hydrazine, formalin, tartaric acid and the like.
Here, when sodium hypophosphite and potassium hypophosphite are used as the reducing agent, the formed electroless plating layer contains phosphorus, and the corrosion resistance and the wear resistance are improved. Further, the electroless plating is stopped immediately before the desired size, and a material having further excellent corrosion resistance, hardness, peelability, etc. is further electrolessly plated, electroplated, sputtered,
When formed using a thin film forming method such as a CVD method, a microlens array mold excellent in corrosion resistance, hardness, peelability, and the like can be manufactured.

As described above, CVD includes, for example, thermal-CVD, LP-CVD, and plasma-CVD, and when these methods are used, the growth rate of the obtained precipitate is controlled in the order of nm. Therefore, the curvature and the like can be easily and accurately controlled. As the precipitate, metal carbide, boride, nitride, oxide, and the like can be obtained. Also,
Even in CVD, stop just before the desired size, and further electroless plating a material with excellent corrosion resistance, hardness, peelability, etc.,
When formed using a thin film forming method such as an electroplating method, a sputtering method, or a CVD method, a microlens array mold excellent in corrosion resistance, hardness, peelability, and the like can be manufactured. Furthermore,
Also in this case, for example, using a transparent material for the substrate,
By CVD by precipitating Si0 _2, it is also possible to produce a like variety of curvature of controlled hemispherical shape, or micro lenses having a hemispherical shape and aspheric shape. Also,
By controlling the CVD material, the refractive index of the substrate, and their thickness, the focal length and position can also be controlled.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described with reference to the drawings. A method for manufacturing a microstructure array such as a microlens array mold of the present invention, and details of a microlens array mold and a microlens array manufactured using the same will be described below with reference to FIGS. 1 to 9. I do.

The steps of manufacturing a microlens array mold or a microlens array will be described with reference to FIGS. First, the openings 7, 1 are formed on the substrates 5, 12, 17, 24 shown in FIGS. 1 to 6 (a) by using a semiconductor lithography process capable of forming a minute opening and, if necessary, an etching process.
A mask layer 6, 13, 18, 25 having 4, 19, 26 is formed. In this case, the mask layers 6, 13, 18, and 25 need to be resistant to a solution or gas for etching the substrate. This may be any material that protects the substrate from the portion other than the portion to be etched exposed from the opening from etching, and either an inorganic mask layer or an organic mask layer can be used.

When the substrate having the mask layer is isotropically etched from the opening, the required number of minute projections as shown in FIGS. 1 (b) to 6 (b) can be produced. here,
The schematic diagrams shown in FIGS. 1 to 6 show cross sections in the diagonal direction AA ′ as shown in FIG.

The outline of the electroless plating will be described with reference to FIG. Electroless plating is performed on a plurality of microprojections obtained by etching using an electroless plating solution 29, and an electroless plating layer 8 is grown until a desired radius of curvature is obtained. In this case, as shown in FIG. 8, the hemispherical structure 9 can be obtained because it grows isotropically by electroless plating from the tip of the minute projection. This is used as a microlens array mold or the like.

Further, as shown in FIG. 4C, when the electroless plating layer 20 is formed by using the substrate 17 in which the etching shape is further etched than a hemispherical state,
As shown in (1), it is possible to obtain a structure 21 in which the skirt portion of the hemispherical structure is aspheric. This is used as an aspherical microlens array mold or the like.

In these cases, depending on the physical properties of the substrate, the substrate may be subjected to an activation treatment, if necessary, to promote the adhesion of the electroless plating layer and the uniform deposition on the substrate surface. Examples of the activation method include immersion in an activation solution and formation of a metal film on the substrate surface. However, the method is not limited thereto as long as it promotes electroless plating. When the substrate is used for electroless plating as it is, no activation treatment is required.

FIG. 2 shows an outline of CVD. CVD is performed on a plurality of microprojections obtained by etching, and a CVD deposition layer 10 is grown until a desired radius of curvature is obtained. In this case, as shown in FIG. 9, since the vaporized deposition material 30 is isotropically grown from the tip of the microprojection by CVD,
A structure 11 that is very close to a hemisphere is formed. This can be used as a microlens array mold or the like.

As shown in FIG. 5 (c), when the CVD deposition layer 22 is formed using the substrate 17 in which the etching shape is further etched than a hemispherical state, as shown in FIG. 5 (e). In addition, a structure 23 in which the skirt portion of the hemispherical structure is made aspherical is obtained. This can be used as an aspherical microlens array mold or the like.

Next, another CVD will be outlined with reference to FIG. CVD is performed on a plurality of microprojections obtained by etching the translucent substrate 12, and a CVD deposition layer 15 is grown until a desired radius of curvature is obtained. In this case, as shown in FIG. 9, the structure 11 grows isotropically from the tip of the microprojection by CVD, so that the structure 11 very close to a hemisphere is formed. In this case, since both the substrate 12 and the deposition layer 15 have translucency, they can be used as they are as the microlens array 16.

Further, as shown in FIG. 6, when the CVD deposition layer 27 is formed by using the translucent substrate 24 in which the etching shape is further etched than in the state of the hemisphere, as shown in FIG. Then, a structure 28 is obtained in which the skirt portion of the hemispherical structure is made aspherical. This can be used as an aspherical microlens array or the like. Furthermore, in this case,
The distance and position of the focal point can be controlled by controlling the refractive index and the thickness of each of the translucent substrate 24 and the CVD material formed thereon.

In the above description, the size of the microlens array mold and the microlens array to be manufactured is typically in the range of several μm to several hundred μm, and the apertures are arranged in accordance with the desired size and pitch. The portions are formed on the mask layer, and the substrate is isotropically etched from the portions to form minute projections. Then, a microlens array mold, a microlens array, and the like are manufactured by performing electroless plating or CVD on this. in this case,
Since the etching shape approaches a hemisphere or a semi-cylinder as the size of the opening is smaller, the size of the opening is preferably as small as possible.

Any material can be used for the substrate as long as it is isotropically etched. For example, Si, Ni, Al, Cu, Cr, etc. can be used. If it is a thing, it is not limited to this. When a microlens array or the like is to be manufactured, a light-transmitting substrate needs to be used. For example, SiO ₂ , resin, or the like is used. If it is a thing, it is not limited to this. In this case, any of a gas phase system and a liquid phase system can be used as an etching method. For example, plasma etching, acid etching, alkali etching, or the like is used. The etching amount of the substrate can be controlled by the etching conditions, time, and the like. In addition, if the substrate is a material that conducts electricity, the substrate can be isotropically etched by an electrolytic etching method.

When the substrate on which the fine projections are obtained is not suitable for electroless plating, a metal phase is formed on the surface, or
Electroless plating is performed by activating the surface by immersing it in a solution of a noble metal catalyst such as Pd or Au.

In the present invention, the shape of the opening is formed to be elongated, and a substrate having the shape formed one-dimensionally or two-dimensionally is used in the above-described method for manufacturing the microlens array mold and the microlens array. A micro lenticular lens array mold, a micro lenticular lens array, etc. can be realized.

An outline of an example of a process for manufacturing a microlens from the above-described microlens array mold will be described below.

First, an example in the case of using as a microlens array mold will be described. This mold has a convex shape. An ultraviolet-curable resin is applied onto the mold obtained in the above-described process, and then the glass is placed on the resin and irradiated with ultraviolet rays from the glass side to cure the resin. After curing,
By peeling the glass and the resin from the mold, a concave microlens array made of a resin whose shape of the plating layer is inverted on the glass is formed. A resin having a higher refractive index than the resin is applied on the concave microlens array, and the resin is cured and flattened, whereby a microlens array can be manufactured. When a microlens array is manufactured by using such a method, alkali glass is not indispensable, and the restrictions on the materials of the microlens array and the support substrate are reduced as compared with the ion exchange method.

Although an example of manufacturing a microlens array using an ultraviolet-curable resin has been described, the mold is heated and stamped using a conventional thermoplastic resin, and a thermosetting resin is applied on the mold. The concave microlens array may be produced by curing the resin by heating, or by irradiating the electron beam-curable resin with an electron beam. Further, by forming a metal film on the obtained concave structure, it can be used as a concave microlens array mold.

Next, an example of manufacturing a microlens array using the substrate on which the plating layer obtained in the above-described process is formed as a microlens array mold master will be described.

An electrode for a reversing mold is formed on the mold master, electroplating is performed on the electrode for the mold, a plating layer is grown to a thickness usable as a mold, and this is peeled off. An electroformed product is obtained. This electroformed product is used as a concave microlens array mold.

An example of a manufacturing process of a microlens array using this concave microlens array mold will be described below. An ultraviolet curing resin, a thermosetting resin, an electron beam curing resin, etc. are applied to a mold, and each resin is cured by applying an ultraviolet ray, heat, an electron beam, and the like, and the mold is separated from the resin to form a convex mold. Is manufactured. It is also possible to heat and mold the mold using a thermoplastic resin to produce a convex microlens array. In addition, by directly transferring the microlens array to glass using a reflow method, a microlens array can be manufactured directly on a glass substrate.

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

(First Embodiment) A manufacturing example of a microlens array mold and a microlens array of this embodiment will be described with reference to the manufacturing process diagram of FIG.

A 1.5-inch by 1-inch silicon wafer having a silicon nitride film of 1 μm on both surfaces was formed on a substrate 5 by LP-CVD using 2 chlorosilane and ammonia as a source.
Used as On this substrate 5, a photoresist (not shown) is applied by a photolithography process, exposed,
Develop to form openings in the photoresist on the silicon nitride film. This opening is circular and its diameter is 5 μm
It is. The openings are arranged at equal intervals of 18 μm in a 700 × 700 matrix. In this case, to prevent the silicon nitride film on the back surface of the substrate 5 from being etched, the back surface is also coated with a photoresist.

Here, the opening 7 is formed in the silicon nitride film by removing the silicon nitride film exposed from the opening of the photoresist by reactive ion etching using CF ₄ as an etching gas. Here, the substrate 5 as shown in FIG. 1A using the silicon nitride film as the mask layer 6 can be manufactured by removing the photoresist.

Next, the substrate 5 is immersed in an etching solution composed of hydrofluoric nitric acid and acetic acid, and silicon of the substrate 5 is isotropically removed from the opening 7. Etching is opening 7
Etching ends when they merge in the diagonal direction of
A substrate 5 etched into a hemispherical shape as shown in FIG.

The silicon nitride film 6 is subjected to reactive ion etching using CF ₄ as an etching gas.
Is removed to produce a substrate 5 as shown in FIG. 1 (c). Further, Al was added to this substrate 5 by 1 μm using a sputtering method.
After forming, an activation process is performed.

Subsequently, the substrate 5 was subjected to electroless Ni plating at 90 ° C. using an electroless Ni plating solution containing a hypophosphite reducing agent (S-780, manufactured by Nippon Kanigen Co., Ltd.). Do
An electroless plating layer 8 is formed. Further, by growing the plating layer 8 to a desired size, a hemispherical structure 9 as shown in FIG. 1 (f) was obtained, and a microlens array mold master was obtained.

When the radius of curvature of the plating layer 8 located at the center of the array was measured, it was found to be 15 μm or less, and the in-plane distribution of the radius of curvature of the plating layer 8 located at the end of the array was about 13%.
From this, by combining isotropic etching and electroless plating, in-plane distribution is reduced and glossiness is high,
A microlens array mold master having a shape close to a hemisphere was obtained.

Further, by performing electroforming on this, a microlens array mold can be manufactured. A UV curable resin is applied to each of the microlens array mold master and the microlens array mold, then the glass is placed on the resin, and the resin is cured by irradiating ultraviolet rays from the glass side, and the glass and the resin are separated. As a result, a concave microlens array and a convex microlens array could be produced.

(Second Embodiment) A manufacturing example of the microlens array mold of this embodiment will be described with reference to the manufacturing process diagram of FIG.

Using a LP-CVD method using 2 chlorosilane and ammonia as a source, a silicon wafer having a length of 1.5 inches × 1 inch and having a silicon nitride film formed on both sides at 1 μm was formed on a substrate 17.
Used as On this substrate 17, a photoresist (not shown) is applied by a photolithography process, exposed,
Develop to form openings made of photoresist on the silicon nitride film. Here, too, the opening is circular and its diameter is 5 μm. Openings are 18 in a 700 x 700 matrix
They are arranged at intervals of μm. Also in this case, the back surface is coated with a photoresist in order to prevent the silicon nitride film on the back surface of the substrate from being etched.

Next, the opening 19 is formed by removing the silicon nitride film exposed from the opening by reactive ion etching using CF ₄ as an etching gas. Further, by removing the photoresist, a substrate as shown in FIG. 4A using the silicon nitride film as the mask layer 18 is manufactured.

Subsequently, this is immersed in an etching solution composed of hydrofluoric nitric acid and acetic acid, and silicon is isotropically etched through the opening 19. When the etching is isotropically etched 2 μm deeper than the point where the etching merges in the diagonal direction of the opening 19, the etching is terminated, and the substrate 17 as shown in FIG. By performing reactive ion etching using CF ₄ as an etching gas, the silicon nitride film 18 was removed, and a substrate 17 as shown in FIG. 4 (c) was produced.

Next, 1 μm of Al is formed on the substrate 17 by using a sputtering method. In contrast, electroless Ni plating was performed at 90 ° C. using an electroless Ni plating solution containing a hypophosphite reducing agent (S-780, manufactured by Nippon Kanigen Co., Ltd.), and the electroless plating layer 20 was formed. Form. Furthermore, by growing the plating layer 20 to a desired size, a hemispherical structure 21 as shown in FIG. 4 (e) is obtained, and a microlens array mold master having an aspherical shape at the base thereof is obtained. Was completed.

When the radius of curvature near the top of the plating layer 20 located at the center of the array was measured, it was found to be 15 μm or less, and the in-plane distribution of the radius of curvature near the top of the plating layer located at the end of the array was about 13%. Was. Thus, by combining isotropic etching and electroless plating, it was possible to obtain a microlens array mold master with reduced in-plane distribution, high gloss, and a shape close to a hemisphere.

As in the case of the first embodiment, a microlens array mold can be manufactured by further performing electroforming. Also, a concave microlens array and a convex microlens array can be manufactured using the microlens array mold master and the microlens array mold, respectively.

(Third Embodiment) A manufacturing example of the microlens array mold of this embodiment will be described with reference to the manufacturing process diagram of FIG.

As in the above embodiment, a 1.5 inch × 1 inch silicon wafer having a silicon nitride film of 1 μm on both surfaces is used as the substrate 5 by LP-CVD using 2 chlorosilane and ammonia as a source. An opening 7 is formed in the substrate 5 as in the above embodiment. Thus, a substrate 5 as shown in FIG. 2A using the silicon nitride film as the mask layer 6 is manufactured.

This is immersed in an etching solution consisting of hydrofluoric nitric acid and acetic acid, and silicon is isotropically etched through the opening 7. The etching is terminated at a point where the etching merges in the diagonal direction of the opening 7, and a substrate 5 etched into a hemispherical shape as shown in FIG. 2 (b) is produced. By performing reactive ion etching using CF ₄ as an etching gas, the silicon nitride film 6 is removed, and a substrate 5 as shown in FIG. 2C is manufactured.

The substrate 5 was coated with SiO ₂ by plasma CVD.
By growing 10 to a desired size, a hemispherical structure 11 as shown in FIG. 2 (f) can be obtained. Thus,
A microlens array mold master was obtained.

When the radius of curvature of the SiO ₂ layer 10 located at the center of the array was measured, it was 15 μm or less, and the in-plane distribution of the radius of curvature of the plating layer located at the end of the array was about 11%. Thus, by combining isotropic etching and CVD, it was possible to obtain a microlens array mold master with reduced in-plane distribution, high gloss, and a shape close to a hemisphere.

In this embodiment, similarly to the first embodiment, a microlens array mold can be manufactured by further performing electroforming. Also, a concave microlens array and a convex microlens array can be manufactured using the microlens array mold master and the microlens array mold, respectively.

(Fourth Embodiment) An example of manufacturing a microlens array according to the present embodiment will be described with reference to the manufacturing process shown in FIG.

In this embodiment, a 1.5-inch long × 1-inch wide Si film is formed by depositing a 1 μm Cr film on both surfaces by using an electron beam evaporation method.
0 ₂ is used as a transparent substrate 12. A photoresist (not shown) is applied, exposed, and developed on the substrate 12 by a photolithography process to form an opening made of the photoresist on the Cr film. This opening is circular and has a diameter of 5 μm. The openings are arranged in a 700 × 700 matrix at intervals of 18 μm. In this case, a photoresist is coated on the back surface to prevent the Cr film on the back surface from being etched.

The opening 14 is formed by etching and removing the Cr film 13 exposed from the opening of the photoresist using an etching solution composed of a mixed solution of diammonium cerium 6 nitrate and perchloric acid. I do. Further, by removing the photoresist, the Cr film becomes the mask layer 13 (FIG. 3A)
A substrate 12 as shown in FIG.

Next, the substrate 12 is immersed in an etching solution composed of a hydrofluoric acid solution, and the SiO ₂ substrate 12 is isotropically removed from the opening 14. The etching is completed at a point where the openings 14 meet in a diagonal direction, and a hemispherically etched substrate 12 as shown in FIG. 3B is produced. this,
The Cr film 13 is removed by immersion in an etching solution composed of a mixed solution of diammonium cerium nitrate 6 and perchloric acid, and a substrate 12 as shown in FIG.

Subsequently, SiO ₂ 15 is grown to a desired size on the substrate 12 by using the plasma CVD method.
A microlens array 16 as shown in FIG. 3 (f) can be obtained.

The radius of curvature of the plating layer located at the center of the array was measured to be 15 μm or less, and the in-plane distribution of the radius of curvature of the plating layer located at the end of the array was about 11%. Thus, by combining isotropic etching and CVD, a hemispherical microlens array with reduced in-plane distribution could be obtained.

(Fifth Embodiment) A manufacturing example of the microlens array mold of the present embodiment will be described with reference to the manufacturing process diagram of FIG.

In this embodiment, 1.5 inches long × 1 inch wide
Al is used as the substrate 17. A photoresist 18 is applied on this substrate 17 by a photolithography process, exposed,
Develop to form openings 19 in the photoresist. The opening 19 has a circular shape and a diameter of 5 μm. Aperture
Reference numeral 19 denotes a 700 × 700 matrix arranged at intervals of 18 μm. In this case, the back surface is also coated with a photoresist in order to prevent Al on the back surface from being etched.

The Al exposed from the opening 19 is isotropically removed by using an Al etching solution comprising a mixed solution of phosphoric acid, nitric acid and acetic acid. 2 μm isotropic, further from the point where the etching merges in the diagonal direction of the opening 19
At the point of deep etching, the etching is completed, and FIG.
A substrate 17 as shown in FIG. Photoresist 18
Is removed to produce a substrate 17 as shown in FIG. 5 (c).

The substrate 17 is coated with Si0
₂ 22 by growing to the desired size to obtain the hemispherical structure 23, as shown in FIG. 5 (e). Thus, a microlens array mold master having an aspherical shape at the foot of the hemispherical structure 23 was obtained.

When the radius of curvature near the top of the SiO ₂ layer located at the center of the array was measured, the in-plane distribution of the radius of curvature near the top of the SiO ₂ layer located at the end of the array was less than 15 μm.
11%. Thus, by combining isotropic etching and CVD, it was possible to obtain a microlens array mold master with reduced in-plane distribution and high gloss and having a shape close to a hemisphere.

In this embodiment, similarly to the first embodiment, a microlens array mold can be manufactured by further performing electroforming. Also, a concave microlens array and a convex microlens array can be manufactured using the microlens array mold master and the microlens array mold, respectively.

[0095]

As described above, the method of manufacturing the microlens array mold and the microlens array of the present invention, and the microlens array mold and the microlens array manufactured by using the microlens array mold and the microlens array are manufactured by etching. By forming a deposition layer from the produced micro projections using a chemical deposition method, it is possible to obtain a microstructure array such as a microlens array mold close to a hemispherical shape with reduced in-plane distribution with good controllability. Can be.

If this is a microlens array mold master, a microlens array mold can be manufactured by electroforming the master. From these, a concave microlens array and a convex microlens array can be manufactured. In addition, a microlens array or the like can be directly manufactured by combining a light-transmitting substrate with CVD or the like.

When a mold such as a hemispherical structure obtained by this production method is used as a mold master and a mold is produced by electroforming, the mold can be produced easily at low cost. In addition, a microlens array or the like manufactured from this mold has the same shape as the mold master, and it is possible to manufacture at least 1,000 or more microlens arrays from one mold. Mass production is possible with good reproducibility.

Further, in the present invention, a microlens array mold, a microlens array, etc. having an aspherical shape can be manufactured by controlling the amount of etching and the amount of deposition. Even when a mold is manufactured by an electroforming method using a structure having an aspherical shape or the like obtained as a mold master, a mold having an aspherical shape can be easily manufactured at low cost. In addition, the microlens array manufactured from this mold also has the same shape as the mold master, and it is possible to fabricate at least 1000 or more aspherical microlens arrays from one mold. Therefore, also in this case, mass production can be performed with good reproducibility.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a configuration of a substrate used in a first embodiment of the present invention and a process of a method of manufacturing a microlens array mold.

FIG. 2 is a cross-sectional view illustrating a configuration of a substrate used in a third embodiment of the present invention and a process of a method of manufacturing a microlens array mold.

FIG. 3 is a cross-sectional view illustrating a configuration of a substrate used in a fourth embodiment of the present invention and a process of a method for manufacturing a microlens array.

FIG. 4 is a cross-sectional view illustrating a configuration of a substrate used in a second embodiment of the present invention and a process of a method of manufacturing a microlens array mold.

FIG. 5 is a cross-sectional view illustrating a configuration of a substrate used in a fifth embodiment of the present invention and a process of a method of manufacturing a microlens array mold.

FIG. 6 is a cross-sectional view illustrating a step of a method for manufacturing a microlens array having an aspheric shape according to the present invention.

FIG. 7A is a plan view showing a configuration of a substrate used in the present invention;
(b) It is sectional drawing.

FIG. 8 is a diagram illustrating the principle of producing a structure such as a hemisphere by electroless plating according to the present invention.

FIG. 9 is a diagram illustrating the principle of manufacturing a structure such as a hemisphere by CVD of the present invention.

FIG. 10 is a schematic view of (a) a sectional view and (b) a top view of a microlens array mold manufactured in a conventional process.

[Explanation of symbols]

 1,5,17 Substrate 2 Electrode layer 3 Insulating mask layer 4 Hemispherical structure 6,13,18,25 Mask layer 16,28 Microlens array 7,14,19,26 Opening 29 Electroless containing metal ions Plating layer 8,20 Electroless plating layer 30 Vaporized deposition material 9,11,21,23 Hemispherical structure of the present invention 10,15,22,27 CVD deposition layer 12,24 Translucent substrate

Claims (26)

[Claims] 1. A method for manufacturing a microstructure array, comprising: (1) forming a mask layer on a surface of a substrate; (2) forming a plurality of openings in the mask layer; Forming a substrate having fine projections by etching the substrate from the part, (4) removing the mask layer, and (5) forming a deposited layer on the substrate using a chemical deposition method. A method for manufacturing a microstructure array, comprising: 2. The method for producing a microstructure array according to claim 1, wherein the etching in the step (3) is isotropic etching. 3. The method according to claim 1, wherein in the step (2), the opening has a circular shape. 4. The method according to claim 3, wherein the etching shape in the step (3) is a hemispherical shape. 5. The method for manufacturing a microstructure array according to claim 1, wherein in step (3), a flat surface is not included at a tip of the minute projection obtained by etching. 6. The method of manufacturing a microstructure array according to claim 5, wherein, in the step (3), the etching is terminated when a minute projection having no flat surface at the tip is obtained. . 7. The method according to claim 5, wherein, in the step (3), the etching is continued after an appropriate amount is further continued from a point in time when a minute projection not including a flat surface at the tip is obtained. The method for producing the microstructure array of the above. 8. The method according to claim 6, wherein in the step (5), the deposited layer formed on the substrate having the fine projections has a hemispherical or semicylindrical shape. 9. The method according to claim 5, wherein in the step (5), the deposited layer formed on the substrate having the fine projections has a hemispherical or semicylindrical shape and an aspherical or noncylindrical shape.
3. The method for producing a microstructure array according to item 1. 10. The method for producing a microstructure array according to claim 1, wherein the deposition layer in the step (5) is formed by electroless plating. 11. The method according to claim 5, wherein the deposit in the step (5) is formed by chemical deposition (CVD)
10. The method for manufacturing a microstructure array according to claim 1, wherein the microstructure array is formed. 12. The method of manufacturing a microstructure array according to claim 1, wherein, in the step (2), all the openings have the same shape. 13. The method according to claim 1, wherein the openings are regularly arranged in the step (2). 14. The method for manufacturing a microstructure array according to claim 1, wherein the microstructure array is a mold for a microstructure array. 15. The method according to claim 14, wherein the mold for a microstructure array is a mold for a microlens array. 16. The method for manufacturing a microstructure array according to claim 1, wherein the microstructure array is a microlens array. 17. A microstructure, comprising: a substrate having fine projections at the tip not including a flat surface; and a deposition layer formed on the substrate having the fine projections by a chemical deposition method. array. 18. The microstructure array according to claim 17, wherein the substrate is translucent. 19. The microstructure array according to claim 17, wherein a deposition layer formed by a chemical deposition method is translucent. 20. The microstructure array according to claim 17, wherein the deposition layer has a hemispherical or semicylindrical shape. 21. The microstructure according to claim 17, wherein the deposited layer has a hemispherical or semicylindrical shape and an aspherical or noncylindrical shape formed at a foot portion of the shape. Body array. 22. The microstructure array according to claim 17, wherein the deposition layer is an electroless plating layer. 23. The microstructure array according to claim 17, wherein the deposition layer is a CVD layer. 24. The microstructure array according to claim 17, which is a mold for a microstructure array. 25. The microstructure array according to claim 24, wherein the microstructure array is a mold for a microlens array. 26. The microstructure array according to claim 17, wherein the microstructure array is a microlens array.