JP2003112323A - Microstructure, mold for microlens array and manufacturing method for microstructure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a microstructure such as a mold for a microlens array or the like capable of easily forming an aspherical or non-cylindrical surface shape, capable of forming the microlens array with a large area and capable of enhancing a fill factor, and a method for manufacturing the same. SOLUTION: In the method for manufacturing the microstructure such as the mold for the microlens array or the like, first insulating mask layers 3 and 4 having opening parts 5 and 6 are formed on the conductive part 2 of a substrate 1 having the conductive part 2 and an electroplating layer 7 or electrodeposition layer is formed on the opening part 5 and the first insulating mask layer 3 while the opening part 6 including the electroplating layer 7 or electrodeposition layer is formed on the second insulating mask layers 3 and 4 and an electroplating layer 8 or electrodeposition layer is formed on the opening part 6, the electroplating layer 7 or electrodeposition layer and the second insulating mask layers 3 and 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microlens array, a mold for producing the same, or a mold master (in the present specification, a mold master is also referred to as a mold master unless otherwise specified). Used in a broad sense including), a microstructure, a method for manufacturing the same, and the like.

[0002]

2. Description of the Related Art A microlens array is an array of micro-sized lenses and is widely known in the field of optoelectronics.

In recent years, as the development of surface emitting lasers, etc., in which the distance between the light emitting elements can be narrowed and the arraying is easy, there is an increasing demand for a microlens array having a narrow lens distance and a large numerical aperture (NA). Similarly, in the light-receiving element, the element interval is narrowed with the development of the semiconductor process technology, and the light-receiving element is further miniaturized as seen in, for example, CCD. Therefore, a microlens array having a large numerical aperture and an excellent fill factor is required also in order to improve the light utilization efficiency.
In addition, high-luminance, high-definition liquid crystal displays are being actively developed, and there is also a demand for a low-cost, large-area microlens array that plays a role of improving luminance and sharpness.

Generally, when an attempt is made to increase the numerical aperture of a lens while maintaining its spherical shape, the spherical aberration is increased accordingly and various optical characteristics are deteriorated (see FIG. 6). Therefore, it is necessary to make the lens aspheric. Similarly, in the case of a microlens, it is necessary to make the lens shape aspherical in order to further improve the light utilization efficiency with respect to the light receiving element which is becoming smaller in size.

The relationship between the lens shape and the light collection rate will be described with reference to FIG. FIG. 6 shows the optical characteristics of the hemispherical lens 36. As can be seen from the figure, the light 38 refracting in the vicinity of the lens peripheral portion 37 has a large incident angle 39, so that the degree of refraction is larger than that of the refracted light 38 in the lens central portion, and the focal length is It becomes shorter (the focus position 41 becomes closer to the lens (high refractive index portion) 36). This becomes remarkable as the incident angle 39 increases. Further, as the incident angle 39 increases, part of the incident light 38 becomes reflected light 40 and is not collected, and this also becomes remarkable as the incident angle 39 increases. Therefore, an aspherical lens is required.

[0006]

As a conventional method for producing an aspherical microlens array, a mask layer formed on the surface of a flat plate is provided with two or more apertures provided around the position of each lens to be produced. A method of providing a mold by partially chemically etching the flat plate surface through these openings, and obtaining a mold for molding an aspherical microlens array from the mold (Japanese Patent Laid-Open No. 5-150103). Gazette). However, in this method, when isotropic etching using a chemical reaction is used, even if the crystal structure in the etching substrate is slightly changed, it may not be possible to perform etching into a desired shape.

As another method, a desired radius of curvature of the lens-type element is determined, and the punch having the radius of curvature is used to experimentally form the lens-type elements adjacent to each other in a lattice-like array on the substrate, and the periphery thereof is formed. Measure the surface height error at the radial measurement line of the arbitrary lens type element surrounded by, and replace this error with the correction amount to numerically control the radius of curvature of the punch (NC)
There is a method (Japanese Unexamined Patent Publication (Kokai) No. 6-154934) in which a shape is corrected by a polishing machine or the like and a punch having the corrected shape is used to accurately obtain a microlens mold having a desired shape including an aspherical surface.

However, in this method, for example, when it is attempted to form a large number of concave molds in a large area, it takes a very long time, and depending on the durability of the punch, the concave molds having a uniform shape in the plane are formed. It may be difficult to fabricate.

As another method, a photosensitive resin is applied onto a substrate, and the resin is patterned into a disk-shaped array pattern according to the number and intervals of lenses by a photolithography method, and the disk-shaped array pattern is formed. A method of rounding a resin into a spherical shape by heat treatment, performing dry etching using the spherical resin as a mask, and transferring a shape close to the shape of the mask onto a substrate and using a mold made of a master mold is used. is there. In this case, an aspherical microlens array can be provided by performing dry etching under conditions set so that the etching rate of the substrate is higher than the etching rate of the mask.
-104106).

However, in this method, since dry etching is performed according to a disk-shaped resin mask, a flat portion exists between lens portions in the mother die after etching, and an aspherical microlens array having a high fill factor. Is difficult to make.

An object of the present invention is to solve various problems which the conventional aspherical microlens array manufacturing techniques have. That is, according to the present invention, (1) an aspherical surface or a non-cylindrical surface shape can be easily produced and controlled,
(2) It is an object of the present invention to provide a microstructure such as a microlens array and a mold for a microlens array, which can be formed into a large-area array and (3) a high fill factor, and a manufacturing method thereof.

[0012]

A method of manufacturing a microstructure such as a mold for a microlens array according to the present invention which achieves the above object, uses a substrate having a conductive portion at least in a part thereof. Forming a first insulating mask layer having an opening thereon, (2) forming an electroplating layer or an electrodeposition layer on the opening and the first insulating mask layer, (3) Forming an opening including an electroplating layer or an electrodeposition layer in the second insulating mask layer, (4) electroplating the opening, the electroplating layer or electrodeposition layer, and the second insulating mask layer Or a step of performing electrodeposition, and further, the steps (3) to (4) are performed at least once or more. Here, when the steps (3) to (4) are performed plural times, the second insulating mask layers may be the same or different.

Based on the above basic configuration, the following modes are possible. The first insulating mask layer and the second insulating mask layer may be different from each other or may be the same. In another case, the insulating mask layer may be composed of a plurality of deposited layers, and the layers may be sequentially removed from the upper layer when new electroplating or electrodeposition is performed. Further, in this case, the plurality of deposited layers of the insulating mask layer have openings having different sizes in advance for each layer, and another opening can appear as the upper layer is removed. At this time,
The sizes of the openings of the plurality of deposited layers of the insulating mask layer increase from the upper layer to the lower layer. in this case,
Since the step of forming the openings in the plurality of deposition layers in advance is a photolithography process on a flat substrate before forming the electroplating layer or the electrodeposition layer, the position of the openings or There is an advantage that it is easy to maintain high accuracy of the diameter. If they are the same, electroplating or electrodeposition is carried out from the opening previously formed in the insulating mask layer, and the conductive portion is exposed by removing a part of the insulating mask layer, and at least the electroplating layer is formed. It is also possible to form an opening larger than the electrodeposition layer. In this case, when forming the second and subsequent openings by photolithography, it is difficult to secure the patterning accuracy due to the unevenness of the plating layer or the electrodeposition layer, but the same insulating layer removal step is required. It has the advantage that it can be used repeatedly.

The opening may have a circular shape, a polygonal shape such as a slit shape, or an elliptical shape. The first electroplating layer or electrodeposition layer formed from such openings may have a substantially hemispherical or semi-cylindrical surface shape in accordance with the circular shape or slit shape. The electroplating layer or electrodeposition layer formed from another opening including the electroplating layer or electrodeposition layer may have a part having an aspherical surface or a non-cylindrical surface shape.

[0015] Typically, the openings are arranged in an array at a plurality of locations. In this case, in the electroplating layer or the electrodeposition layer, a step of making adjacent electroplating layers or the electrodeposition layers into a fly eye may be further included. The fly-eye process is performed by electroplating or electrodeposition, electroless plating, CVD (chemical vapor deposition) or PV.
It is performed using the D method (physical vapor deposition). These may be appropriately selected depending on the case, along with the shape of the opening, the method of electroplating or electrodeposition prior to the fly-eye forming process, and the like. Here, fly-eye conversion means a plurality of electroplating layers or electrodeposition layers obtained by electroplating or electrodeposition, with or without an insulating mask layer, electroplating, electroless plating, It is to connect the adjacent electroplating layers or electrodeposition layers without leaving a flat portion by using a method capable of forming a continuous film such as CVD or PVD.

The microstructure is formed as a mold for a microlens array or a mold for a microlens, a microlens array or a microlens, and the like. It is necessary to select the material according to each object. For example,
To form a microlens array or microlens, the substrate must be glass, the electrode layer must be ITO, and the layer formed thereon must be a transparent substance such as an electrodeposition resin.

Further, a microstructure such as a mold for a microlens array according to the present invention that achieves the above object is a substrate having a conductive portion at least in a part thereof, and a substantially hemisphere or a semicylinder formed on the conductive portion of the substrate. At least one having a shape
First electroplating layer or electrodeposition layer, and second electroplating having spherical or cylindrical surface-shaped portion and aspherical surface or non-cylindrical surface-shaped portion formed on the first electroplating layer or electrodeposition layer It is characterized by having a layer or an electrodeposition layer. This structure is easily manufactured by the above manufacturing method.

Also in this microlens array or microlens mold, structure such as microlens array or microlens, one or more layers of the second electroplating layer or electrodeposition layer may be formed, The plating layer or electrodeposition layer is present in an array array at a plurality of locations, or in the electroplating layer or electrodeposition layer,
Adjacent electroplating layers or electrodeposition layers may form fly eyes.

[0019]

As described above, the method for producing a microstructure such as a mold for a microlens array of the present invention uses a substrate having an electrode layer (conductive portion) on at least a part thereof.
An insulating mask layer is formed on the electrode layer, an electroplating layer or electrodeposition layer is formed from the opening, another opening is formed in the same or different insulating mask layer, and further electroplating or electrodeposition is performed. The step of forming another opening in the insulating mask layer and further performing electroplating or electrodeposition is performed at least once or more.

In this method, when electroplating or electrodeposition is performed from the opening formed in the insulating mask layer,
An electroplating layer or electrodeposition layer isotropically deposited from the opening, and a hemispherical or semicylindrical electroplating layer or electrodeposition layer is obtained on the opening and the insulating mask layer. When an electroplating layer or an electrodeposition layer of a desired size is obtained, for example, as shown in FIG. 1 (c), another opening formed in the lower layer of the insulating mask layer is exposed, When electroplating or electrodeposition is further performed, an electroplating layer or electrodeposition layer is formed from both the opening and the electroplating layer or electrodeposition layer in the opening. As a result, the shape of the skirt portion of the electroplating layer or electrodeposition layer deviates from the spherical or cylindrical shape,
An aspherical or non-cylindrical electroplating layer or electrodeposition layer can be obtained.

In this case, the size of the new additional opening is
It must be larger than the size of the electroplated or electrodeposited layer in the opening, but its shape is set according to the aspherical or non-cylindrical shape to be achieved.

By repeating the steps of forming the openings according to the above and performing electroplating or electrodeposition a required number of times, an electroplating layer or electrodeposition layer having a desired aspherical surface or non-cylindrical portion can be formed. . in this case,
As a method of forming another opening, for example, the previous insulating mask layer is removed and a new insulating mask layer is formed,
A new opening may be formed by a photolithography process, or an unnecessary insulating mask layer region in the previous insulating mask layer may be removed by dry etching to form a new opening. In any case, as long as it is possible to newly expose the conductive layer on at least part of the periphery of the electroplating layer or the electrodeposition layer, a method other than these can be used.

When a plurality of electroplating layers or electrodeposition layers are formed in an array arrangement, any one of electroplating, electroless plating, CVD, PVD (physical vapor deposition), etc.
A fly-eye can be formed by connecting adjacent electroplating layers or electrodeposition layers to each other, whereby a mold for a microlens array having a fill factor of about 100% can be manufactured.

Here, the electroplating solution 3 containing metal ions
The principle of producing an electroplating layer having a hemispherical or semi-cylindrical shape in FIG. 5 will be described with reference to FIG. When electroplating is performed on a minute or fine size opening of the insulating mask layer 33 on the substrate 31 having the conductive layer 32, lines of electric force concentrate on the opening. At this time, lines of electric force are generated not only on the front side of the opening but also in the vicinity of the insulating mask layer 33, and as a result, lines of electric force are generated substantially isotropically with respect to the center or center line of the opening. . Since the electroplating 34 layer grows according to this line of electric force, a substantially hemispherical or semicylindrical shape as shown in FIG. 5 is obtained. This also applies to electrodeposition. The electrodeposition liquid includes an electrodeposition liquid of an electrodeposition organic compound (anion type electrodeposition acrylic resin, cation type electrodeposition epoxy resin, etc.).

In this case, the radius of curvature of the electroplating layer or electrodeposition layer can be controlled by the time of electroplating or electrodeposition, the amount of integrated current, the electroplating or electrodeposition material, etc., if necessary. By electroplating or electrodepositing the electroplating layer or electrodeposition layer having the hemispherical or semicylindrical shape and the new opening, an electroplating layer or electrodeposition layer having an aspherical surface or non-cylindrical surface portion is formed. Although it can be produced, the aspherical surface or non-cylindrical surface shape can be controlled by the time of electroplating or electrodeposition, the integrated current amount, the electroplating or electrodeposition material, etc., so that the focal length of the microlens can be controlled. . Further, the shape of the aspherical surface or the non-cylindrical surface can be controlled by the film forming time, the film forming method, the film material, etc. in the fly-eye process.

In the description of the prior art, the relationship between the shape of the lens and the light collection rate was described with reference to FIG. 6, but the microlens array or microlens obtained from the mold of the present invention described above is shown in FIG. In order to solve the problem described in the section of the above, specifically, the curvature of the central part of the lens is high and the curvature of the peripheral part of the lens is low, so that the focal length of the lens between the central part and the peripheral part is It is possible to reduce the difference and reduce the light loss due to the reflected light.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Here, a mold for a microlens array according to an embodiment of the present invention and a method for manufacturing the same will be described below with reference to FIGS. The cross-sectional views (FIGS. 1 to 3) used in the description of the embodiment and the examples described below are
It is a figure showing the cross-sectional view of a diagonal direction as shown in FIG. 4, or the cross-sectional view of the direction which crosses a slit-shaped opening part. In FIG. 4, 27 indicates a substrate and 28 indicates a conductive layer (electrode layer).
, 29 indicates an insulating mask layer, and 30 indicates an opening.

Representatively, referring to FIG. 1, a structure of a work and a method for producing a mold for a microlens array are shown. First,
A conductive layer 2 is formed on the substrate 1 as shown in FIG. For this purpose, a conductive thin film is formed using a thin film forming method such as a sputtering method, a resistance heating method, or an electron beam evaporation method.

Next, an insulating mask layer having openings is formed by using a semiconductor photolithography process capable of forming minute or minute openings and etching. In this case, the insulating mask layer may be any material having an insulating property against electroplating or electrodeposition, and either an inorganic insulator or an organic insulator can be used.
However, the insulating mask layer is selected from materials having resistance to the electroplating solution or the electrodeposition solution.

In this case, a plurality of insulating mask layers 3 and 4 are used.
When the openings 5 and 6 having different sizes are provided for each insulating mask layer, the insulating mask layers 3 and 4 are preferably selected from combinations of materials that are selectively etched. As an example, phosphosilicate glass (PS is formed on the insulating mask layer 4 by using the CVD method.
First, the opening 5 is formed in the insulating mask layer 3 by photolithography using an organic resist for the insulating mask layer 3. Furthermore, the opening 6 is obtained by etching the insulating mask layer 4 exposed from the opening 5 to an arbitrary size. Thus, the work as shown in FIG. 1A (or FIG. 2A and FIG. 3A) is obtained.

In this case, the shapes of the openings 5 and 6 of the insulating mask layers 3 and 4 can be arbitrarily formed according to the shape of the desired microlens. It is possible to fabricate a mold for forming a portion to obtain a lenticular-shaped microlens array.

Further, it is possible to manufacture microlens array dies having various aspherical or non-cylindrical surface shapes depending on the ratio of the opening sizes of the insulating mask layers 3 and 4.

Next, an electroplating layer 7 or an electrodeposition layer is formed from the opening 5 by electroplating or electrodeposition. In this case, by growing the electroplating layer 7 or the electrodeposition layer on the insulating mask layer 3 as well, the electroplating layer 7 or the electrodeposition layer (or the electroplating layers 15, 24 having a hemispherical shape or a semi-cylindrical shape) is formed. Or an electrodeposition layer) can be formed.

Next, the insulating mask layer 3 is removed, and then electroplating or electrodeposition is performed. In this case, electroplating layer 7
The shape of the electroplating layer 8 or the electrodeposition layer formed from the electrodeposition layer and the opening 6 can be controlled by controlling the sizes of the opening 6 and the electroplating layer 7 or the electrodeposition layer in advance. This is possible, and thus, a mold having various aspherical or non-cylindrical surface-shaped portions can be manufactured. The obtained electroplating layer 8 or electrodeposition layer can be formed by connecting adjacent electroplating layers or electrodeposition layers to each other, if necessary.
(D) (or FIG. 2 (d), FIG. 3 (e)) can be a fly-eye type mold.

In the case of connecting adjacent electroplating layers 8 or electrodeposition layers to each other, if a method using a material suitable as a mold as a deposit is used, electroplating method, electroless plating method, CVD method, or PVD method. Any of the above methods may be used.

In the mold obtained by the above process, first, an approximately hemispherical or semicylindrical electroplating layer or electrodeposition layer is produced. Since the peripheral portion of the electroplated layer or the electrodeposited layer that isotropically grows in this way becomes an aspherical surface or a non-cylindrical surface, a microlens array obtained from this has a non-numerical aperture (NA) excellent. It becomes a spherical surface or a non-cylindrical surface.

In the above, the electroplating layer or electrodeposition layer is formed by the deposition of metal ions in the plating solution or the resin in the electrodeposition solution by an electrochemical reaction. Also, the deposition amount of the electroplating layer or electrodeposition layer can be easily controlled by controlling the temperature, current value, material, etc. of the electrodeposition liquid. The deposition rate can be controlled easily by controlling the temperature of the liquid, the current value, and the like, and if it is slowed down, the deposition can be stopped easily and reliably at a desired location.

The main deposits of electroplating are Ni, Au, Pt, Cr, Cu, Ag, Zn, etc. for single metals, and Cu-Zn, for alloys.
There are Sn-Co, Ni-Fe, Zn-Ni, etc., and other materials can be used as long as they can be electroplated. Especially Ni,
Cr, Cu and the like are preferable as the material of the mold because they allow easy bright plating.

The deposition amount of the electroless plating layer can be easily controlled by controlling the plating time, the temperature of the plating solution, and the like.
As precipitates, Ni, Au, Cu, Co, etc., alloys such as Co-Fe, Co
-W, Ni-Co, Ni-Fe, Ni-W, etc. Examples of the reducing agent include sodium hypophosphite, potassium hypophosphite, sodium borohydride, potassium borohydride, hydrazine, formalin and tartaric acid. If sodium hypophosphite or potassium hypophosphite is used as the reducing agent, the electroless plating layer will contain phosphorus, and the corrosion resistance and wear resistance will be improved.

When performing CVD, the deposition amount of the CVD layer can be easily controlled by controlling the deposition conditions, time and the like. CVD methods include thermal CVD, plasma CVD, optical CV
There are D, MO (organic metal compound) CVD, metal CVD, etc., and either method can be used as necessary.

The types of CVD precipitates are Cu, Be, A
There are single metals such as l, Ti, Zr, Sn, Ta, Co, Cr, Fe, Si, Ni, Pt, and Pd. Furthermore, some of these can be obtained as alloys, carbides, nitrides, borides, suicides, oxides. When forming a mold, a material suitable as a material for the mold may be selected and used from these.

An outline of a process for producing a microlens array from the above-mentioned mold for microlens array will be described below.

First, an example of using the above structure as it is as a mold will be described. This mold is convex. An ultraviolet curable resin is applied onto this mold, glass is then placed on the resin, and ultraviolet rays are irradiated from the glass side to cure the resin. After the curing, the glass and the resin are peeled off from the mold, so that the concave microlens array made of the resin in which the shape of the mother mold is inverted is formed on the glass.

A microlens array can be manufactured by applying a resin having a refractive index higher than that of the resin on the concave type microlens array, curing the resin, and flattening the resin. When such a method is used, alkali glass is not indispensable when manufacturing a microlens array, and the restrictions on the lens material and the supporting substrate material are reduced as compared with the ion exchange method.

In the above, an example of manufacturing a microlens array using an ultraviolet curable resin has been shown. However, a conventional thermoplastic resin is used to heat and stamp a mold, or a thermosetting resin is applied onto the mold. A concave microlens array may be produced by applying and heating to cure the resin, or by applying an electron beam curing resin on a mold and irradiating with an electron beam to cure the resin.

Further, by forming a metal film on the obtained concave microlens array, this can also be used as a matrix for obtaining a convex microlens array.

Next, an example of manufacturing a microlens array by using an electroforming method will be described. By forming an inverted mold electrode on a mold master for a microlens array, electroplating the mold electrode, growing an electroplated layer to a thickness that can be used as a mold, and peeling it off. The obtained electroformed product can be used as a concave mold. An example of a manufacturing process of a microlens array using this concave mold will be described below.

An ultraviolet curable resin, a thermosetting resin, an electron beam curable resin, or the like is applied onto the concave mold, and ultraviolet rays, heat, or an electron beam is applied according to each resin to cure the resin. A microlens array can be manufactured by peeling off the resin and the like. It is also possible to fabricate a convex microlens array by a stamp method in which a thermoplastic resin is used and a mold is heated to stamp the resin. Also,
If the reflow method is used, it is also possible to directly press the mold onto the reflowed glass and directly transfer the mold to the glass to directly fabricate the microlens array on the glass substrate.

[0049]

EXAMPLE A more specific example will be described below.

Example 1 Example 1 will be described with reference to FIG. In this embodiment, a silicon wafer measuring 1.5 inches in length and 1 inch in width is used as the substrate 1. On this wafer 1,
By sputtering, which is one of the thin film formation methods, Ti
The conductive layer 2 was formed by depositing a layer of 50 nm and a Pt layer of 200 nm.

Next, PS is formed on the conductive layer 2 by the CVD method.
G4 was formed into a film of 0.1 μm. Further, a photoresist 3 was applied thereon, exposed and developed by a photolithography process to form an opening 5. By forming the opening 6 by dissolving the PSG ₄ exposed from the opening 5 with an etching solution composed of HF and NH ₄ F, as shown in FIG.
Insulating mask layers 3 and 4 having openings 5 and 6 as shown in (a) were formed. The opening 5 is circular and has a diameter of 2 μm. The opening 6 is also circular and has a diameter of 14 μm. Openings 5 and 6 are 1024 × 76
8 in the form of a matrix, arranged at 25 μm intervals.

Next, using this substrate as a work, Ni
Perform electroplating. Here, the electrode layer (conductive layer) 2
As the cathode, nickel sulfate, nickel chloride, boric acid, and
First, using Ni plating bath consisting of brightener, bath temperature 50 ℃
Phase cathode current density 40A / dm ^TwoElectroplating with
The electroplated layer 7 was deposited from the mouth 5. Electroplating layer
7 spreads over the insulating mask layer 3 as shown in FIG. 1 (b).
A substantially hemispherical shape having a diameter of 8 μm was obtained.

Next, the insulating mask layer 3 was removed with an organic solvent to expose the opening 6 of the insulating mask layer 4. When electroplating is performed from the opening 6, an electroplating layer grows from the opening 6 and the electroplating layer 7 to form an electroplating layer 8 having an aspherical portion at the hem as shown in FIG. 1 (c). Was done. Thus, a mold for microlens array could be obtained.

Further, by continuing the electroplating until the electroplating layers 8 were connected to each other, a fly-eye type microlens array mold as shown in FIG. 1D could be obtained.

(Second Embodiment) A second embodiment will be described with reference to FIG. Also in this embodiment, a silicon wafer having a length of 1.5 inches and a width of 1 inch is used as the substrate 9. On this wafer 9,
By sputtering, which is one of the thin film formation methods, Ti
By forming a layer of 50 nm and further Pt of 200 nm,
The conductive layer 10 was formed.

Next, P is formed on the conductive layer 10 by the CVD method.
SG12 was deposited to a thickness of 0.1 μm. Further thereon, a photoresist 11 was applied, exposed and developed by a photolithography process to form an opening 13. Opening 13
The exposed PSG 12 is dissolved by using an etching solution composed of HF and NH ₄ F to form the opening 14, so that the insulating mask layer 11 having the openings 13 and 14 as shown in FIG. , 12 were formed. Opening 13
Has a circular shape and its diameter is 2 μm. Opening 1
4 is also circular and has a diameter of 14 μm. The openings 13 and 14 are 2 in a matrix of 1024 × 768.
They are arranged at intervals of 5 μm.

Next, using this substrate as a work, using the electrode layer 10 as a cathode, and using a Ni plating bath composed of nickel sulfate, nickel chloride, boric acid and a brightener, a bath temperature of 5 was obtained.
Ni electroplating was performed at 0 ° C. and an initial cathode current density of 40 A / dm ² , and an electroplating layer 15 was deposited through the opening 13. The electroplated layer 15 spreads over the insulating mask layer 11, and a substantially hemispherical shape having a diameter of 8 μm as shown in FIG. 2B was obtained.

Next, the insulating mask layer 11 was removed with an organic solvent to expose the opening 14 of the insulating mask layer 12.
When electroplating is performed from the opening 14, an electroplating layer grows from the opening 14 and the electroplating layer 15, and FIG.
The electroplated layer 16 having an aspherical surface-shaped portion as shown in FIG.

Further, until each electroplating layer 16 is connected,
A fly-eye forming layer 17 is formed by performing electroless Ni plating at a bath temperature of 90 ° C. for about 50 minutes using an electroless Ni plating solution containing a reducing agent of hypophosphite, as shown in FIG. 2 (d). It was possible to obtain a fly-eye-shaped mold for a microlens array as shown.

(Third Embodiment) A third embodiment will be described with reference to FIG. Also in this embodiment, a silicon wafer having a length of 1.5 inches and a width of 1 inch is used as the substrate 9. A conductive layer 10 was formed on this wafer by forming a Ti layer with a thickness of 50 nm and a Pt with a thickness of 200 nm by a sputtering method, which is one of the thin film forming methods.

Next, P is formed on the conductive layer 10 by the CVD method.
SG12 was deposited to a thickness of 0.1 μm. Further thereon, a photoresist 11 was applied, exposed and developed by a photolithography process to form an opening 13. Opening 13
The exposed PSG 12 is dissolved by using an etching solution of HF and NH ₄ F to form the opening 14, so that the insulating mask layer 11 having the openings 13 and 14 as shown in FIG. , 12 were formed. Opening 13
Has a circular shape and its diameter is 2 μm. Opening 1
4 is also circular and has a diameter of 14 μm. The openings 13 and 14 are 2 in a matrix of 1024 × 768.
They are arranged at intervals of 5 μm.

Using this substrate as a work, the electrode layer 10
With a nickel plating bath consisting of nickel sulfate, nickel chloride, boric acid, and a brightener as a cathode, and a bath temperature of 50 ° C.,
Ni electroplating was performed at an initial cathode current density of 40 A / dm ² , and an electroplating layer 15 was deposited through the opening 13. The electroplated layer 15 spreads over the insulating mask layer 11, and a substantially hemispherical shape having a diameter of 8 μm as shown in FIG. 2B was obtained.

Next, the insulating mask layer 11 was removed with an organic solvent to expose the opening 14. When electroplating was performed through the opening 14, an electroplating layer grew from the opening 14 and the electroplating layer 15, and an electroplating layer 16 having an aspherical surface portion as shown in FIG. 2C was formed.

Further, until each electroplating layer 16 is connected,
By depositing the PSG layer (fly-eye forming layer) 17 using the CVD method, a fly-eye-shaped microlens array mold as shown in FIG. 2D could be obtained.

(Fourth Embodiment) A fourth embodiment will be described with reference to FIG. Also in this embodiment, a silicon wafer measuring 1.5 inches in length and 1 inch in width is used as the substrate 18. On this wafer
By sputtering, which is one of the thin film formation methods, Ti
By forming a layer of 50 nm and further Pt of 200 nm,
The conductive layer 19 was formed.

Next, P is formed on the conductive layer 19 by using the CVD method.
SG21 was deposited to a thickness of 0.1 μm. Further thereon, a photoresist 20 was applied, exposed and developed by a photolithography process to form an opening 22. Opening 22
The more exposed PSG 21 is dissolved using an etching solution of HF and NH ₄ F to form the opening 23, so that the insulating mask layer 20 having the openings 22 and 23 as shown in FIG. , 21 were formed. Opening 22
Has a circular shape and its diameter is 2 μm. Opening 2
3 is also circular and has a diameter of 14 μm. The openings 22 and 23 are 2 in a matrix of 1024 × 768.
They are arranged at intervals of 5 μm.

Using this substrate as a work, the electrode layer 19
With a nickel plating bath consisting of nickel sulfate, nickel chloride, boric acid, and a brightener as a cathode, and a bath temperature of 50 ° C.,
Ni electroplating was performed at an initial cathode current density of 40 A / dm ² , and an electroplating layer 24 was deposited through the openings 22. The electroplating layer 24 also spreads over the insulating mask layer 20, and a substantially hemispherical shape having a diameter of 8 μm as shown in FIG. 3B was obtained.

Next, the insulating mask layer 20 was removed with an organic solvent to expose the opening 23. When electroplating was performed through the opening 23, an electroplating layer grew from the opening 23 and the electroplating layer 24, and an electroplating layer 25 having an aspherical shape portion as shown in FIG. 3C was formed.

Next, the PSG 21 was dissolved using an etching solution of HF and NH ₄ F to expose the conductive layer 19 as shown in FIG. 3 (d). The fly-eye forming layer 26 is formed on this substrate by electroplating until the respective electro-plating layers 25 are connected to each other to obtain a fly-eye-shaped mold for microlens array as shown in FIG. 3 (e). I was able to.

(Fifth Embodiment) A fifth embodiment will be described. An example of manufacturing the microlens array mold of this embodiment will be described with reference to the manufacturing process chart of FIG. In this case, in order to describe an example for obtaining a lenticular-shaped microlens array,
FIG. 1 is a sectional view crossing a slit-shaped opening. Also in this embodiment, a silicon wafer measuring 1.5 inches long and 1 inch wide is used as the substrate 1. A Ti layer having a thickness of 50 n is formed on the wafer 1 by a sputtering method which is one of thin film forming methods.
The conductive layer 2 was formed by depositing m and Pt to a thickness of 200 nm.

Next, PS is formed on the conductive layer 2 by the CVD method.
G4 was formed into a film of 0.1 μm. Further, a photoresist 3 was applied thereon, exposed and developed by a photolithography process to form an opening 5. The PSG ₄ exposed from the opening 5 is dissolved by using an etching solution of HF and NH ₄ F to form the opening 6, so that the PSG ₄ shown in FIG.
Insulating mask layers 3 and 4 having openings 5 and 6 as shown in (a) were formed. The opening 5 has a rectangular shape with a line width of 2 μm and a length of 5 mm. Opening 6
Also has a substantially rectangular shape with a line width of 14 μm and a length of 5 mm. The openings 5 and 6 are 768 at intervals of 25 μm.
Book is arranged.

Using this substrate as a work, using the electrode layer 2 as a cathode and a Ni plating bath consisting of nickel sulfate, nickel chloride, boric acid and a brightener, at a bath temperature of 50 ° C. and an initial cathode current density of 40 A / dm ² . Ni electroplating was performed to deposit an electroplating layer 7 through the opening 5. The electroplating layer 7 spreads over the insulating mask layer 3 as shown in FIG.
A lenticular-shaped layer (semi-cylindrical layer) having a substantially semicircular cross section with a width of 8 μm as shown in FIG.

Next, the insulating mask layer 3 was removed with an organic solvent to expose the opening 6. When electroplating was performed from the opening 6, an electroplating layer grew from the opening 6 and the electroplating layer 7, and an electroplating layer 8 having a non-cylindrical cross section as shown in FIG. 1C was formed. . Further, by continuing the electroplating until each electroplating layer 8 is connected,
It was possible to obtain a lenticular-shaped mold for a microlens array having a fly's eye shape as shown in (d).

[0074]

As described above, in the microstructure such as the mold for the microlens array and the method of manufacturing the same according to the present invention, the conductive substrate, the substrate having the electrode layer, or at least a part thereof has conductivity. In the step of forming an insulating mask layer on the substrate, forming an opening, and forming an electroplating layer or an electrodeposition layer from the opening,
For example, by forming an insulating mask layer and openings in a plurality of stages and performing electroplating or electrodeposition while changing the size of the openings, an electroplating layer or electrodeposition having an aspherical surface or a non-cylindrical surface shape is performed. A layer can be obtained, which can be obtained as a mold for a microlens array or the like.

In this case, the shape of the aspherical surface or the non-cylindrical surface can be easily controlled by combining the size of the opening and the size of the electroplating or electrodeposition. By making the plating layer or electrodeposition layer fly-eye, the fill factor is about 100.
%, It is possible to manufacture a mold for a microlens array and the like. Further, since all the processes can be performed on one substrate and the method used for the process can easily cope with the large size, the same process can be applied even if the large size is used.

Since the microlens array manufactured from this mold for microlens array is aspherical, the light utilization efficiency of the peripheral portion of the lens is improved. In addition, a mold having the same shape as the mold can be obtained, and at least 1000 or more microlens arrays can be manufactured from one mold, and thus mass production can be performed with good reproducibility.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of the structure of a substrate used in the present invention and a method for manufacturing a microlens array mold.

FIG. 2 is a cross-sectional view showing another example of the structure of the substrate used in the present invention and the method for manufacturing the microlens array mold.

FIG. 3 is a cross-sectional view showing another example of the structure of the substrate used in the present invention and the method for manufacturing the microlens array mold.

FIG. 4 is a diagram illustrating a cross-sectional direction of a cross-sectional view used for describing the present invention.

FIG. 5 is a diagram illustrating the principle of manufacturing a hemispherical or semi-cylindrical structure by electroplating or electrodeposition used in the present invention.

FIG. 6 is a schematic diagram illustrating optical characteristics of a hemispherical or semi-cylindrical lens.

[Explanation of symbols]

1, 9, 18, 27, 31 Substrates 2, 10, 19, 28, 32 Conductive layers 3, 4, 11, 12, 20, 21, 29, 33 Insulating mask layers 5, 6, 13, 14, 22, 23, 30 openings 7, 8, 15, 16, 24, 25 electroplating layer or electrodeposition layer 17, 26 fly-eye forming layer 34 electroplating layer or electrodeposition layer 35 having a hemispherical or semicylindrical surface shape Electroplating liquid containing 36 Hemispherical lens (high refractive index part) 37 Lens peripheral part 38 Incident light (parallel light) 39 Incident angle (°) 40 Reflected light 41 Focus position

Claims (21)

[Claims] 1. A method of manufacturing a microstructure, comprising the steps of: (1) forming a first insulating mask layer having an opening on a conductive portion, using a substrate having a conductive portion at least in a part thereof; (2) A step of forming an electroplating layer or an electrodeposition layer on the opening and the first insulating mask layer, (3) A second opening including the electroplating layer or the electrodeposition layer
(4) forming an insulating mask layer on the insulating mask layer, and (4) performing electroplating or electrodeposition on the opening, the electroplating layer or the electrodeposition layer, and the second insulating mask layer. )-(4) are performed at least once or more, The manufacturing method of the microstructure characterized by the above-mentioned. 2. The method for producing a microstructure according to claim 1, wherein the first insulating mask layer and the second insulating mask layer are different from each other. 3. The method for producing a microstructure according to claim 1, wherein the first insulating mask layer and the second insulating mask layer are the same. 4. The method for producing a microstructure according to claim 2, wherein the insulating mask layer is composed of a plurality of deposited layers, and the layers are sequentially removed from the upper layer when new electroplating or electrodeposition is performed. . 5. The method for manufacturing a microstructure according to claim 4, wherein the plurality of deposited layers of the insulating mask layer have openings having different sizes in advance for each layer. 6. The method for producing a microstructure according to claim 5, wherein the size of the openings of the plurality of deposited layers of the insulating mask layer increases from the upper layer to the lower layer. 7. The method for producing a microstructure according to claim 1, wherein the opening has a circular shape. 8. The method for producing a microstructure according to claim 1, wherein the opening has a polygonal shape such as a slit shape or an elliptical shape. 9. A part of the electroplating layer or the electrodeposition layer has a spherical or cylindrical surface shape.
9. The method for manufacturing a microstructure according to any one of 8 to 8. 10. The method for producing a microstructure according to claim 1, wherein a part of the electroplated layer or the electrodeposited layer has an aspherical surface or a non-cylindrical surface shape. 11. The method for producing a microstructure according to claim 1, wherein the openings are arranged in an array at a plurality of locations. 12. The electroplating layer or electrodeposition layer further comprising a step of forming adjacent electroplating layers or electrodeposition layers into fly-eyes.
The method for producing a microstructure according to item 1. 13. The method for producing a microstructure according to claim 12, wherein the step of forming a fly eye uses an electroplating or electrodeposition method. 14. The method for producing a microstructure according to claim 12, wherein the step of forming a fly eye uses an electroless plating method. 15. The method for producing a microstructure according to claim 12, wherein a CVD method or a PVD method is used in the step of forming the fly eye. 16. The fabrication of a microstructure according to claim 1, wherein the microstructure is a microlens array or a mold for microlenses, or a microlens array or a microlens. Method. 17. A substrate having a conductive portion on at least a part thereof, at least one first electroplating layer or electrodeposition layer having a substantially hemispherical or semi-cylindrical shape formed on the conductive portion of the substrate, and the first electroplating layer. A microstructure comprising a second electroplating layer or electrodeposition layer having a spherical or cylindrical surface-shaped portion and an aspherical surface or non-cylindrical surface-shaped portion formed on the electroplating layer or electrodeposition layer. 18. The microstructure according to claim 17, wherein one or more layers of the second electroplating layer or electrodeposition layer are formed. 19. The microstructure according to claim 17, wherein the electroplating layer or the electrodeposition layer is arranged in an array at a plurality of locations. 20. The microstructure according to claim 19, wherein in the electroplating layer or electrodeposition layer, adjacent electroplating layers or electrodeposition layers are fly-eye-shaped. 21. A microlens array or a mold for a microlens, or a microlens array or a microlens.
The microstructure according to 0.