JP3513478B2 - Die for micro structure array, micro structure array, and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A microlens array has a plurality of minute, substantially hemispherical lenses each having a diameter of several μm to several 100 μm, and is used in various liquid crystal display devices, light receiving devices, fiber-to-fiber connections in optical communication systems, etc. It has come to be used for purposes.

On the other hand, the development of surface emitting lasers, etc., in which the distance between the light emitting elements can be narrowed and which can be easily formed into an array, is progressing, and there is an increasing demand for a microlens having a large distance between lens arrays and a large numerical aperture (NA).

Similarly, in the light receiving element, with the development of the semiconductor process technology, the element interval is narrowed, and the light receiving element is further miniaturized as seen in CCD and the like. As a result, here again, a microlens array with a narrow lens interval and a large numerical aperture is required. In such a microlens, there is a demand for a microlens having a high light condensing ratio, which has high utilization efficiency of light incident on the lens surface.

Further, there are similar demands in the optical information processing fields expected in the future, such as optical parallel processing / calculation and optical interconnection.

In addition, electroluminescence (EL)
Research and development of self-luminous display devices such as the above have been actively conducted, and proposals for high-definition and high-luminance displays have been made. In such a display, in addition to a microlens array having a small size and a large numerical aperture, there is a demand for a low cost, large area microlens array.

Further, in a microlens array mounted on a liquid crystal projector or the like, in order to eliminate a decrease in the light collection rate due to the displacement between the microlens and the pixel portion and obtain a brighter image, a driving substrate It is necessary to provide an alignment marker that realizes highly accurate alignment with the.

[0008]

[Problems to be Solved by the Invention] Under the above circumstances, the conventional ion exchange method (M. Oikawa, et al., Jpn. J.
Appl. Phys. 20 (1) L51-54, 1981) is used to form a plurality of lenses by increasing the refractive index at a plurality of locations on a substrate made of multi-component glass to form a plurality of lenses. It has been known. However, with this method, 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.
In addition, a large-scale manufacturing device such as an ion diffusion device is required to manufacture a large-area microlens array, and there is a problem that manufacturing is not easy. In addition, compared to molding using a mold, it is necessary to perform an ion exchange process for each glass, and unless the manufacturing conditions of the manufacturing equipment are carefully controlled, lens quality, for example, variation in focal length is large between lots. There was a problem of becoming. In addition, this method is more expensive than the method using a mold.

Further, in the ion exchange method, alkali ions for ion exchange are indispensable in the glass substrate, the substrate material is limited to alkali glass, and compatibility with semiconductor-based devices which are premised on alkali ion free Is bad. Furthermore, since the coefficient of thermal expansion of the glass substrate itself is greatly different from the coefficient of thermal expansion of the substrate of the light receiving device or the light emitting device,
As the integration density of devices increases, misalignment occurs due to mismatch of thermal expansion coefficients. Originally, it is known that the ion exchange method for the glass surface leaves a compressive strain on the surface, and the problem of the trade-off between the residual stress and the warp deformation of the glass surface is inevitably caused, and the microlens array becomes large-sized. As a result, it becomes difficult to bond and join the substrate of the light receiving device or the light emitting device.

Another method is the 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, heated and reflowed to manufacture a microlens array. By this method, lenses of various shapes can be manufactured at low cost. In addition, there are no problems such as thermal expansion coefficient and warpage as compared with the ion exchange method. However, in this method, the shape of the microlens strongly depends on the thickness of the resin, the wettability between the substrate and the resin, and the heating temperature. Variations are likely to occur.

Another method is to prepare an original plate of a microlens array, apply a lens material to the original plate, and peel off the applied lens material. In the production of a mold as an original plate, a method of drawing with an electron beam (JP-A-1-261601) and a method of etching a part of a metal plate (JP-A-5-30309)
Issue gazette). According to these methods, the microlens can be duplicated by molding, variation from lot to lot does not easily occur, and it can be produced at low cost. Further, as compared with the ion exchange method, it is possible to avoid problems such as occurrence of alignment error and warpage due to the difference in thermal expansion coefficient. However, in the method using the electron beam, the electron beam drawing apparatus is expensive, a large amount of capital investment is required, and the drawing area is limited.
There is a problem that it is difficult to produce an original plate having a large area of a corner or more.

As another method, a mask layer having a one-dimensionally or two-dimensionally arranged opening pattern is formed on a base material, and etching is performed from the opening (Japanese Patent Laid-Open No. Hei.
8-136704). However, in this method, since etching is performed from the resist opening,
The bottom of the dug portion is flattened, and it is difficult to collect light below the diameter of the opening. In addition, since the method of etching mainly uses isotropic etching utilizing a chemical reaction, there is a problem that the composition cannot be etched into a desired shape even if the composition or crystal structure of the base material is slightly changed.

As a method for solving the above-mentioned problems, a hemispherical structure array is prepared by electroplating, a mold for a microlens is prepared using this as an original plate, and a microlens array is prepared from this mold. Has been devised (Japanese Patent Publication No. 64-10169). According to this method, it is possible to manufacture a microlens mold that is easy to make large, the manufacturing process is easy, the controllability is high, and the cost is low. Further, it becomes possible to manufacture a microlens having a small radius of curvature by the method using electroplating.

As a method of forming an alignment marker, there has been proposed a method of forming a pattern for a lens and a pattern for an alignment marker in the same process when forming a resist pattern (Japanese Patent Laid-Open No. 09-189901).

However, in this method, the Japanese Patent Publication No. 64-1016 is used.
When the method of Japanese Patent Publication No. 9 is applied and a pattern for a lens and a pattern for an alignment marker are formed in the same process at the time of forming a resist pattern and electroplating is performed, a current density distribution is generated due to the pattern shape for the alignment marker. However, the electric field is concentrated in the peripheral portion of the array pattern to promote the plating growth, resulting in an in-plane distribution in the size of the hemisphere. Further, a current density distribution is generated around the alignment marker pattern, which causes a distribution in the size of the plating layer grown in a desired microlens array region.

The present invention has been made in view of the above problems of the prior art, and its objects are (1) easy fabrication process and high controllability, and (2) in-plane microstructure array. The distribution marker can be made smaller, (3) the radius of curvature of the microstructure can be made smaller, (4) it can be applied to a cross-shaped alignment marker, and (5) an easy-to-form alignment marker for realizing highly accurate alignment. It is to provide a mold for a microstructure array such as a microlens array, a microstructure array such as a microlens array, and a manufacturing method thereof, which can be provided.

[0017]

A method of manufacturing a microstructure array such as a mold for a microlens array of the present invention which achieves the above object uses a substrate having a conductive portion,
(1) a step of forming an insulative first mask layer on the conductive portion, (2) a plurality of microstructure openings at intervals corresponding to a desired microstructure array array in the first mask layer And (3) forming a first plating layer or an electrodeposition layer on the opening and the first mask layer through the opening by electroplating or electrodeposition using the conductive portion as a cathode. Step (4) Two or more first plating layers adjacent to each other at appropriate positions on the desired microstructure array region of the substrate and the first plating layer or electrodeposition layer and outside the microstructure array region Or a step of forming a second mask layer on the electrodeposition layer region, (5) a step of etching away the first plating layer or the electrodeposition layer in the region where the second mask layer is not formed, 6) Process for removing the second mask layer A method of manufacturing a microstructure array having: a second mask layer covered with a second mask layer at an appropriate position outside the desired microstructure array region in step (4). The plating layer or electrodeposition layer is used for forming an alignment marker.

In this manufacturing method, the alignment marker structure is formed in the same process using the same openings as the openings for forming the desired microstructure array, so that the alignment marker structure can be easily manufactured. it can. In addition, since the plurality of microstructure openings are only formed at intervals corresponding to the desired microstructure array arrangement (that is, it is not necessary to specifically form the alignment marker openings), the plating layer or the electrode is not necessary. The current density distribution when forming the deposition layer is suppressed, and a microstructure array having a relatively small size in-plane distribution can be easily manufactured. Furthermore, by selectively forming the second mask layer, it is possible to select a desired microstructure array region having a small in-plane distribution and an alignment marker structure having a desired shape. Therefore, the microstructure having a smaller in-plane distribution can be selected. The body array can be easily produced, and the pattern of the alignment marker can be flexibly set according to the application.

Based on the above basic structure,
More specific embodiments are possible. Further, the step (3)
After (7), the step of (7) removing the first mask layer may be performed. If possible, a second mask layer may be selectively formed on the structure obtained in the step (3) (the PSG has good adhesion to the conductive portion). It is possible in such cases as in this case, in this case a plurality of first
Plating layer or electrodeposition layer may be separated or may be formed until it becomes continuous), and the second mask layer is selectively formed on the structure obtained by removing the first mask layer. You may form in.

Further, after the step (6), (8) a step of forming a second plating layer or an electrodeposition layer from the first plating layer or the electrodeposition layer to the conductive portion or the first mask layer. Can be done. As a result, the in-plane distribution of the microstructure array can be further reduced, and the first plating layer or electrodeposition layer can be firmly fixed to the conductive portion or the first mask layer to further strengthen the structure.

In the step (2), typically, the openings are circular or the openings are arranged at equal intervals in the left-right direction and the up-down direction. A circular or slit-like opening for a microstructure can form a substantially hemispherical or semicylindrical microstructure array (which can be a hemispherical microlens array or a mold for a lenticular lens). This may be determined according to the application.

In the step (5), the first plating layer can be removed by electrolytic etching or the like. In addition, in the step (8), the second plating layer may be formed by electroless plating or the like.

The alignment marker may be a first plating layer or electrodeposition layer formed at an appropriate position outside the microstructure array region, or a first plating layer or electrodeposition layer and a first layer. It may be a cross-shaped aggregate of substantially hemispherical structures composed of the second plating layer or electrodeposition layer.

The above-mentioned microstructure array is typically manufactured as a mold for a microstructure array or a mold for a microlens array.

Further, in the microstructure array such as the mold for the microlens array of the present invention which achieves the above object, a structure for alignment marker is formed outside the microstructure group of the microstructure array, and the alignment marker structure is formed. It is characterized in that the structure is an aggregate of microstructures having a substantially hemispherical plating layer or electrodeposition layer. This can be easily manufactured by the method for manufacturing the microstructure array described above.

[0026] Typically, each microstructure of this microstructure array is also a microstructure composed of the above-mentioned approximately hemispherical plating layer or electrodeposition layer. In addition, the microstructure includes a first plating layer or an electrodeposition layer, or
It comprises one plating layer or electrodeposition layer and a second plating layer or electrodeposition layer formed on the first plating layer or electrodeposition layer.

In this structure, the microstructure of the microstructure array (for example, a hemisphere formed on a conductive substrate or a substrate having an electrode layer and having a cylindrical axis corresponding to the lens group of the microlens array) -Shaped first plating layer, and a microstructure comprising a first plating layer and a second plating layer formed on the electrode layer) and the alignment marker structure (for example, outside the lens group of the microlens array) Of the first marker, the alignment marker structure comprising the first plating layer and the second plating layer formed on the electrode layer and the electrode layer) can be easily made almost equal in height, and the height distribution can be made uniform. Can easily be within 5%.

The structure for alignment marker composed of the above-mentioned assembly includes a line of a line of the microstructure,
The lines of one row of the microstructure may intersect with each other, the lines of two rows of the microstructure may be included, or the lines of two rows of the microstructure may intersect with each other. In this way, by appropriately setting the pattern of the second mask layer, the alignment marker structure can be flexibly set.

Of course, the microstructure array is typically a microstructure array mold or a microlens array mold.

Further, an image pickup device or a display device of the present invention which achieves the above object is a microstructure array configured as the microlens array of the present invention, or a microlens produced by a mold for a microlens array of the present invention. It is characterized in that the lens array is mounted in a state where each microlens is aligned with each light receiving portion or each pixel portion using the alignment marker.

The above are 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.

First, the principle of forming a hemispherical microstructure will be described. Electroplating or electrodeposition (in the following description, plating is used) is performed on a minute or minute opening of an insulating layer formed on a conductive substrate or a substrate having an electrode layer (substrate having a conductive portion). Then, first, a plating layer is deposited in the opening, and when electroplating is further performed, the first plating layer starts to grow on the opening and the mask layer. When the size (diameter or width) of the opening is sufficiently smaller than that of the anode for electroplating, the first plating layer grows isotropically with respect to the center of the diameter or width, and the first plating layer having a hemispherical shape is formed. A plating layer is formed on the opening and the mask layer. By making the shape of the opening circular, the first plating layer can grow isotropically with respect to the center of the diameter on the mask layer. Compared with the method of forming an original plate by etching, if the current flowing between the anode and the cathode is stopped when the desired shape is obtained, the deposition of the plating can be stopped. Unnecessary shape error can be avoided and the controllability of fabrication is good.

Next, a typical example of a method for producing a mold for a microstructure array, which is typically a microlens array, will be shown. Here, when a microlens or a microlens array is referred to, it means a microstructure as a representative. As a matter of course, what is described here can be applied to a method for manufacturing a mold for another microstructure array. First, a first mask layer is formed over a conductive substrate or a substrate having an electrode layer. The plating substrate material may be any of metal, semiconductor, and insulator materials, and a metal plate having a good flatness, a glass substrate, a silicon wafer, or the like can be used. If a metal material is used as the plating substrate, it is not necessary to form the electrode layer. Further, when a semiconductor is used, it is not always necessary to form an electrode layer as long as it has a conductivity that allows electroplating. The electrode layer is selected from materials that are not corroded by the plating solution used because they are exposed to the plating solution. However, since a part of the first plating layer formed on this electrode layer is removed by etching in a later step, a material which does not form an alloy layer with the first plating layer is preferable. Further, the electrode layer is preferably made of a material that is not etched in the plating solution. Any material having an insulating property may be used for the first mask layer, and either an inorganic insulator or an organic insulator can be used. As a method of forming the electrode layer and the first mask layer, a vacuum deposition method, a spin coating method, a dipping method, a chemical deposition method (CV) is used.
A thin film forming method such as D) is used.

Next, a plurality of microlens openings are formed in the first mask layer at a pitch corresponding to the pitch of the microlens array in a region wider than a predetermined microlens array group region (that is, use region). To do. The shape of the opening is preferably circular or the like. In forming the opening, the opening is formed by a semiconductor photolithography process capable of forming a minute or fine opening and etching. When a photoresist is used as the first mask layer, the etching process can be omitted (that is, exposure and development are sufficient).

At this time, an opening for forming the alignment marker structure is also formed in the same process at a position corresponding to the alignment marker. This makes it possible to form an alignment marker for realizing highly accurate alignment. An alignment marker corresponding to a marker such as a cross shape can also be formed by arranging the openings to be covered with the second mask layer later.

Electroplating is performed by the following method. Using the plating substrate as a work, it is dipped in a plating solution containing metal ions, an external power supply is connected between the plating substrate and the anode plate, and an electric current is caused to flow to form a first plating layer in the opening. Plating is formed in the opening, and by continuing the plating, the first
The first plating layer also spreads on the mask layer of 1 to form a hemispherical structure. The diameter of the lens formed by the microlens array mold to be produced is from several μm to several tens.
It is in the range of 0 μm, and therefore the size of the opening needs to be smaller than the desired diameter of the microlens. In order for plating growth to become isotropic, the size of the opening should be small compared to the diameter or width of the hemispherical structure, etc. The radius of curvature can be reduced by approaching.

The microstructure is formed by depositing metal ions in the plating bath by an electrochemical reaction.
In electroplating, the thickness of the first plating layer can be easily controlled by controlling the plating time and the plating temperature. The main plating metals are Ni and A for single metals.
There are u, Pt, Cr, Cu, Ag, Zn, etc., and in alloys, Cu-Zn, Sn-Co, Ni-Fe, Zn-Ni.
Etc. Although other electroplatable materials can be used, a material that does not form an alloy layer with the electrode layer is preferable. The above 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 the first plated layer formed here, the peripheral portion of the array grows larger than the central portion. This is because the current distribution is not uniform and the current concentrates at the end portions of the electrodes. Therefore, by forming the microlens opening group area wider than the desired microlens array area (that is, the usage area), the area of the first plating layer that grows excessively larger than the central area is desired. Will be outside the microlens array area.

Then, the first plating layer on the peripheral portion of the array, which has grown excessively larger than the central portion, is removed by selective etching by the method as described below, so that the first plating layer having a substantially uniform height is formed. An array of plated layers can be obtained.

In the typical method, the first mask layer is first removed. Next, the 1st grown to a nearly uniform size
Forming a second mask layer on the desired microlens array area including the plating layer and two or more adjacent first plating layer areas at appropriate positions outside the microlens array area. Here, if the second mask layer is formed so that the first plating layers are arranged in a cross shape, it becomes possible to form a marker structure that can correspond to a cross-shaped marker.

As the second mask layer, either an inorganic material or an organic material can be used, but one having resistance to an etching solution used in a subsequent step is used. As a method for forming the second mask layer, a thin film forming method such as a vacuum vapor deposition method, a spin coating method or a dipping method is used. A semiconductor photolithography process and etching are used to form the second mask layer only in the selected region. Here, if a photoresist is used as the second mask layer, the etching step can be omitted.

Although it is not necessary to remove the first mask layer before forming the second mask layer, the removal of the first mask layer improves the adhesion of the second mask layer to the substrate. In particular, when both the first mask layer and the second mask layer are photoresists, the effect of improving the adhesion is great.

Next, the first plating layer exposed from the second mask layer is removed by etching. As the etching method, dry etching or wet etching is used.
As the etching gas and the etching solution, those which do not etch the second mask layer, the electrode layer, and the substrate but selectively etch the first plating layer exposed from the second mask layer are used.

Further, here, contrary to the case where the first plating layer is formed, electrolytic etching by connecting a cathode and an anode and passing a current from an external power source may be used (this can be used in the case of an electrodeposition layer). Absent). As a result, the first plating layer exposed from the second mask layer is selectively removed by electrolytic etching. Here, if the electrode layer is a material that is not electrolyzed by the plating solution and does not form an alloy layer with the first plating layer, a flat surface of the electrode layer is obtained after electrolytic etching.
Similarly, for the first plating layer, a flat surface of the electrode layer can be obtained if the material does not form an alloy layer with the electrode layer. The metal of the first plating layer removed here can be recovered in the plating solution or the metal plate of the counter electrode, and even an expensive metal material can be used without waste.

The first plating layer in the microlens array region covered with the remaining second mask layer has a substantially uniform size and a hemispherical structure having a small in-plane distribution of diameter or width. It becomes an array. Also, the first plating layer as the alignment marker can be left because it was covered with the second mask layer.

Further, the plurality of microlens openings having intervals corresponding to the desired pitch of the microlens array are:
Since the alignment marker openings are easily formed in the same process, the relative displacement between the microlens array region and the alignment marker does not occur.

Further, according to this method, a plurality of second substrates are provided in the substrate.
By providing the mask layer of, a plurality of or a plurality of types of alignment markers and
It is also possible to obtain a mold for a microlens array having a small in-plane distribution of the size of the plating layer. This is because after forming the first plating layer, a region having a small in-plane distribution of the size of the first plating layer excluding the peripheral portion of the array pattern and a region of the first plating layer as an alignment marker are selected. This is because it is possible to form the second mask layer.

Next, the second mask layer is removed, and a second plating layer or electrodeposition layer is formed from the first plating layer to the electrode layer (also represented by the plating layer here). The method of forming the second plating layer may be either electroplating or electroless plating, but by using electroless plating, a microlens array mold having high gloss can be obtained. Furthermore, since this is isotropic plating growth, the radius of curvature of each plating layer in the microlens array area can be made equal in the diagonal and horizontal directions, and the height and alignment of the plating layer in the microlens array area can be made equal. The heights of the plated layers of the marker structure can be formed to be substantially equal.

As a result, the first plating layer is firmly fixed on the electrode layer, the first plating layer can be prevented from falling off in the subsequent steps, and the durability of the microlens array mold can be improved. .

The height of the plating layer in the microlens array region obtained by these and the height of the plating layer of the alignment marker are substantially equal. Therefore, the height of the lens apex of the microlens array obtained from this and the height of the apex of the alignment marker are substantially equal. As a result, when bonding to a drive substrate, etc., the lens vertex of the microlens array and the vertex of the alignment marker are in substantially the same plane, and both are within the focal depth of the lens system on the aligner side. Positioning can be realized.

The mold for the microlens array is obtained by forming the mold material on the mold master for the microlens array (original plate), and then peeling the mold (depending on the material of each part, the above-mentioned structure). Can be used as is as a microstructure array such as a microlens array). Since the mold for the microlens array can be formed directly from the original plate formed by electroplating, it does not require expensive equipment and can be manufactured at low cost. As a peeling method, the original plate and the substrate may be mechanically peeled. However, if it is enlarged, it may be deformed at the time of peeling. Therefore, a method of sequentially etching and removing the substrate, the mask layer, the first plating layer and the like from the back surface may be adopted.

When the mold is formed after providing the sacrificial layer on the substrate and the second plating layer, the mold and the substrate can be separated by removing the sacrificial layer. In this case, the material of the sacrificial layer is selected so that the mold is not corroded by the etchant for etching the sacrificial layer. If the plating layer and the substrate are not corroded by the etchant that etches the sacrificial layer, the substrate on which the plating layer is formed is used as an original plate.
It can be used multiple times. If the original plate becomes unusable due to scratches, stains, etc. due to multiple use,
A mold master may be manufactured by the same method.

As the material of the mold for the microlens, any material such as resin, metal and insulator can be used as long as it can be formed on a substrate having a plated layer and can be peeled off. As a simple method of forming a mold, a molten or dissolved solution of resin, metal, or glass is applied on a substrate on which a plating layer is formed, and after this is cured, peeling is performed by the above-described peeling method. . In this case, as the die material, a material that does not alloy the substrate or the plating layer is selected. As another method, a metal mold is electroplated on the plating layer and the electrode layer using the substrate as a cathode. If a sacrificial layer is used, a mold electrode layer is formed on the sacrificial layer, and electroplating is performed using the mold electrode layer as a cathode.

Further, a microlens array can be formed by forming a material to be a microlens on the microlens array mold and then peeling it off. This makes it possible to easily manufacture microlenses having the same shape at low cost.
As a material for the microlens, a material that is easily peelable from the microlens mold is used. When a resin is used as the microlens material, a light-transmissive thermosetting resin, an ultraviolet curable resin, an electron beam curable resin, etc. are applied on the mold for the microlens array and then cured by ultraviolet light irradiation, electron beam irradiation, etc. Let Prevent air bubbles from forming during curing. When applying the resin, it is preferable to perform deaeration.

After curing, the resin is peeled off from the mold to form a microlens array. As the resin forming the microlens array, a material that can transmit light in the wavelength region of light used by the light receiving or light emitting device using the microlenses is used. In the case of producing a microlens by the above method, alkali glass is not indispensable, and restrictions on materials for the microlens and the supporting substrate can be reduced as compared with the ion exchange method. If molten glass is used instead of resin, a glass microlens array can be produced.

Of course, the mold of the present invention is not limited to the microlens array, as long as it is applicable, and can be used for manufacturing any structure.

[0057]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments and examples of the present invention will be described in detail below with reference to the drawings.

(First Embodiment) The first embodiment relates to the first embodiment of the mold for microlens array, the microlens array, and the manufacturing method thereof according to the present invention.

This will be described with reference to the manufacturing process diagrams of FIGS. A 4 inch φ silicon wafer having a 1 μm thick silicon dioxide film formed on both sides by thermal oxidation using an oxidizing gas is used as the substrate 1 shown in FIG. On this wafer 1,
Ti and P are formed by vacuum sputtering, which is one of the thin film forming methods.
The electrode layers 2 are formed by continuously forming t with 50Å and 500Å respectively. On top of that, a positive photoresist (Az150
0: manufactured by Client Co., Ltd.) is applied to form the first mask layer 3.

Next, a photoresist is formed on the first mask layer 3, the photoresist is exposed and developed by photolithography, and etching is performed using this as a mask to partially expose the electrode layer 2, A plurality of openings 4 having the same shape are formed. The openings 4 have a circular shape, and are provided in an array of 95 mmφ in the surface of the silicon wafer in an array at equal intervals in the left-right direction and the up-down direction. Its diameter is 5 μm, and the distance between adjacent openings 4 is 18 μm (see FIG. 1).
(A), see FIG. 2).

Using this substrate 1 as a work, the electrode layer 2
As a cathode, a Ni plating bath composed of nickel sulfate, nickel chloride, boric acid and a brightener is used to perform Ni plating at a bath temperature of 50 ° C. and a cathode current density of 40 A / dm ² without stirring. The first plating layer 5 made of Ni first deposits and grows from the opening 4, the first plating layer 5 spreads also on the first mask layer 3, and the radius of the center of the array is about 10 μm in a hemispherical structure. The first plated layer 5 was grown until it became a body (Fig. 1
(B) is a sectional view and FIG. 3 is a top view). When the radius of the first plating layer 5 is about 10 μm at the center of the array, the maximum radius of the first plating layer 5 is about 15 μm at the periphery of the array.
Was formed.

Next, the first mask layer 3 is removed with acetone and N, N-dimethylformamide. Then, a positive photoresist (AzP4620: manufactured by Client Co.) was applied, exposed and developed to remove the peripheral portion of the array 1064 ×.
The second mask layer 6 is selectively provided on the 808 regions and the first plating layer 5 grown at the positions corresponding to the alignment markers. As a result, the first plating layer 5 in the peripheral portion of the array was exposed (FIG. 1C is a sectional view, and FIG. 4 is a top view). Further, here, the second mask layer 6 at the position corresponding to the alignment marker was formed such that 28 first plating layers 5 were arranged in two rows in a cross shape as shown in FIG.

Using this substrate 1 as a work, and using it as an anode, a Ni plating bath consisting of nickel sulfate, nickel chloride, boric acid, and a brightening agent was used and exposed at a bath temperature of 60 ° C. and an anode current density of 8 A / dm ² . Electrolytic etching is performed on the first plated layer 5 (FIG. 1D is a sectional view and FIG. 5 is a top view). Here, since Pt was used as the electrode layer 2, the electrode layer 2 is not corroded. Then, the electrolytic etching was stopped when the first plating layer 5 made of Ni existing in the region not covered with the second mask layer 6 was consumed.

Next, the second mask layer 6 is removed with acetone and N, N-dimethylformamide to obtain 106
An alignment marker 8 composed of an array of 4 × 808 first plating layers 5 and first plating layers 5 arranged in a cross can be formed (FIG. 1E is a cross-sectional view, and FIG. 6 is a top view). ). At this time, the in-plane distribution of the radius of the first plating layer 5 was within 5%.

Next, an electroless Ni plating solution (Alnick CT, manufactured by Pax Co.) containing a reducing agent for hypophosphite is used to perform Ni electroless plating at a bath temperature of 90 ° C. to obtain a second plating layer 7. Are formed (FIG. 1F is a cross-sectional view, and FIG. 7 is a top view). As a result, the first plating layer 5 was firmly fixed on the electrode layer 2, and electroless plating was used to form the second plating layer 7, so that a mold for a microlens array having high gloss was obtained. . In addition, the radius of curvature of each plating layer 7 in the diagonal direction and the horizontal direction (here, the second plating layer 7 is continuously formed so that each hemispherical structure is connected without a plane portion). Are almost equal and the average radius of curvature is 20 μm,
The distribution of the radius of curvature was within ± 1 μm, and a mold having a uniform shape could be formed. Further, the in-plane distribution of the height of the plating layer 7 in the area of the microlens group and the plating layer 7 in the area of the alignment marker 8 was within 5%.

As described above, according to this embodiment, the in-plane distribution of the size of each lens can be easily reduced, and highly accurate alignment can be realized even with respect to the drive substrate side alignment marker 10 as shown in FIG. A method for manufacturing a mold for a microlens array equipped with the easy-to-form cross-shaped alignment marker 8 can be realized.

Next, a process of making a microlens array mold by using the structure manufactured by the above manufacturing method as a mold master will be described.

First, a release agent for electroforming is applied on the second plated layer 7. Using this substrate as a cathode, Ni consisting of nickel sulfamate, nickel bromide, boric acid and a brightener
Using plating bath, bath temperature 50 ℃, cathode current density 5A / d
Ni electroplating is performed at m ² to form a mold. Then, the mold is released from the substrate to form a microlens array mold.

A microlens array is produced using this mold. After applying an ultraviolet curable resin to the microlens array mold, a glass substrate to be a supporting substrate is placed thereon. A convex microlens array was produced by peeling after curing the resin by ultraviolet irradiation. This convex microlens array was equipped with a cross-shaped alignment marker that realized highly accurate alignment and was easily formed, and the in-plane distribution of the lens diameter was within 5%.

Subsequently, the markers formed on the TFT (thin film transistor) liquid crystal substrate are aligned with the markers of the convex microlens array, and the markers are attached to each other so that each microlens is accurately arranged at a position corresponding to each pixel. We were able to. When these were connected to a drive circuit and driven as a liquid crystal projector, incident light was condensed by each microlens and a bright display image could be obtained.

(Second Embodiment) Second Embodiment FIGS. 8 to 1
This will be described using 1. Also in this embodiment, as in the first embodiment, a 4-inch φ silicon wafer having a 1 μm thick silicon dioxide film formed on both surfaces by thermal oxidation using an oxidizing gas is used as the substrate 1. 50 Å each of Ti and Pt is formed on this wafer by vacuum sputtering, which is one of the thin film forming methods
The electrode layer 2 is formed by continuously depositing 500 Å. A positive photoresist (Az1500: manufactured by Client Co.) is applied on top of this to form the first mask layer 3. Next, the photoresist is exposed and developed by photolithography to expose the electrode layer 2, and the opening 4 is formed in the same manner as in the first embodiment.
To form. The openings 4 have a circular shape and are provided in a 95 mmφ area on the surface of the silicon wafer in a uniform pattern in an array. Its diameter is 5 μm, and the distance between adjacent openings 4 is 18 μm.

Subsequently, using this substrate 1 as a work, Ni plating was performed in the same manner as in the first embodiment. Here again, the first plating layer 5 was grown until it became a hemispherical structure having a radius of the central portion of the array of about 10 μm. When the radius of the first plating layer 5 was about 10 μm at the center of the array, the first plating layer 5 having a maximum radius of about 15 μm was formed at the periphery of the array.

Next, as in the first embodiment, the first mask layer 3 is formed.
Is removed, and the second mask layer 6 is selectively provided on the 1064 × 808 regions excluding the peripheral portion of the array and the first plating layer 5 grown at the position corresponding to the alignment marker. As a result, the first plated layer 5 on the peripheral portion of the array is exposed (FIG. 8). In the second embodiment, the second mask layer 6 is formed such that 21 first plating layers 5 are arranged in a line in a cross shape as shown in FIG.

Further, as in the first embodiment, the substrate 1 was used as a work, and using it as an anode, a Ni plating bath consisting of nickel sulfate, nickel chloride, boric acid and a brightener was used, and the bath temperature was 60 ° C. The exposed first plating layer 5 is electrolytically etched at a current density of 8 A / dm ² (see FIG.
9). The electrolytic etching was stopped when the first plating layer 5 made of Ni existing in the region not covered with the second mask layer 6 was consumed.

Next, as in the first embodiment, the second mask layer 6 is removed, so that 1064 × 808 first mask layers are formed.
It was possible to form an alignment marker 8 consisting of an array of the plating layers 5 and the cross of one row of the first plating layers 5 (FIG. 10). At this time, the in-plane distribution of the radius of the first plating layer 5 was within 5%.

Further, as in the first embodiment, the second plated layer 7 is formed (FIG. 11). As a result, a mold for microlens array having a high gloss in which the first plating layer 5 was firmly fixed on the electrode layer 2 was obtained. Similar to the first embodiment, the radius of curvature of each plating layer in the diagonal direction and the horizontal direction is almost equal, the average radius of curvature is 20 μm, the distribution of the radius of curvature is within ± 1 μm, and the metal having a uniform shape is formed. The mold could be formed. Furthermore, the in-plane distribution of the height of the plating layer in the microlens group region and the plating layer in the alignment marker region was within 5%.

As described above, according to the present embodiment, the in-plane distribution of the size of each lens can be easily reduced, and furthermore, the cross-shaped pattern for realizing highly accurate alignment with the drive substrate side alignment marker 10 as shown in FIG. A method of manufacturing a mold for a microlens array equipped with an alignment marker could be realized.

It is needless to say that the above substrate can be used as a mold master for a microlens array to fabricate a mold for a microlens array and further a convex microlens array as in the first embodiment. This convex microlens array was equipped with a cross-shaped alignment marker for realizing highly accurate alignment, and the in-plane distribution of the lens diameter was within 5%.

(Third Embodiment) A third embodiment will be described with reference to FIGS. Also in this embodiment, as in the first embodiment, a 4-inch φ silicon wafer having a silicon dioxide film with a thickness of 1 μm formed on both surfaces by thermal oxidation is used as the substrate 1. Ti and Pt are respectively 50Å and 5 by a vacuum sputtering method which is one of the thin film forming methods on this wafer.
00Å The film is continuously formed to form the electrode layer 2. A positive photoresist (Az1500: manufactured by Client Co.) is applied on top of this to form the first mask layer 3. Next, the photoresist is exposed and developed by photolithography to expose the electrode layer 2 to form the opening 4.

Here again, the openings 4 have a circular shape and are provided in an array in a region of 95 mmφ in the surface of the silicon wafer. Its diameter is 5 μm, and the distance between adjacent openings 4 is 18 μm.

Subsequently, using this substrate 1 as a work, Ni plating was performed as in the first embodiment. Here again, the first plating layer 5 was grown until it became a hemispherical structure having a radius of the central portion of the array of about 10 μm. When the radius of the first plating layer 5 was about 10 μm at the center of the array, the first plating layer 5 having a maximum radius of about 15 μm was formed at the periphery of the array.

Next, as in the first embodiment, the first mask layer 3 is formed.
Is removed, and the second mask layer 6 is selectively provided on the 1064 × 808 regions excluding the peripheral portion of the array and the first plating layer 5 grown at the position corresponding to the alignment marker. As a result, the first plated layer 5 on the peripheral portion of the array is exposed (FIG. 12). In the second embodiment, the second mask layer 6 includes 20 first plating layers 5 as shown in FIG.
Were formed so as to be diagonally arranged in two rows in a cross shape. Therefore, the second mask layer 6 in the portion of the first plating layer 5 arranged in a cross in a diagonal direction is removed.

Further, as in the first embodiment, the substrate 1 was used as a work, and using it as an anode, a Ni plating bath consisting of nickel sulfate, nickel chloride, boric acid and a brightener was used, and the bath temperature was 60 ° C. The exposed first plating layer 5 is electrolytically etched at a current density of 8 A / dm ² (see FIG. 1).
3). The electrolytic etching was stopped when the first plating layer 5 made of Ni existing in the region not covered with the second mask layer 6 was consumed.

Next, as in the first embodiment, the second mask layer 6 is removed, so that 1064 × 808 first mask layers 6 are formed.
It was possible to form an alignment marker 8 composed of an array of the plating layers 5 and two diagonal crosses of the first plating layer 5 (FIG. 14). At this time, the in-plane distribution of the radius of the first plating layer 5 was within 5%.

Further, as in the first embodiment, the second plated layer 7 is formed (FIG. 15). As a result, a mold for microlens array having a high gloss in which the first plating layer 5 was firmly fixed on the electrode layer 2 was obtained. Similar to the first embodiment, the radius of curvature of each plating layer in the diagonal direction and the horizontal direction is almost equal, the average radius of curvature is 20 μm, the distribution of the radius of curvature is within ± 1 μm, and the metal having a uniform shape is formed. The mold could be formed. Furthermore, the in-plane distribution of the height of the plating layer in the microlens group region and the plating layer in the alignment marker region was within 5%.

As described above, according to the present embodiment, the in-plane distribution of the size of each lens can be easily reduced, and further, it is highly accurate for the driving substrate side alignment marker 10 inclined with respect to the pixel 9 as shown in FIG. A method of manufacturing a mold for a microlens array equipped with a cross-shaped alignment marker for realizing alignment can be realized.

It is needless to say that the above-mentioned substrate can be used as a mold master for a microlens array to fabricate a mold for a microlens array and further a convex microlens array as in the first embodiment. This convex microlens array was equipped with an inclined cross-shaped alignment marker that realizes highly accurate alignment, and the in-plane distribution of the lens diameter was within 5%.

(Fourth Embodiment) A fourth embodiment will be described with reference to FIG. In this embodiment, a 5-inch φ silicon wafer having a silicon dioxide film with a thickness of 1 μm formed on both sides by thermal oxidation using gas is used as the substrate 1. On this wafer, Ti and Pt are continuously formed by 50 Å and 500 Å, respectively, by a vacuum sputtering method, which is one of the thin film forming methods.
To form. On top of that, a positive photoresist (Az15
00: manufactured by Client Co., Ltd.) to apply the first mask layer 3
To form. Next, the photoresist is exposed and developed by photolithography to expose the electrode layer 2 to form the opening 4.

Here again, the openings 4 have a circular shape and are provided in an array within a region of 120 mmφ in the surface of the silicon wafer. Its diameter is 5 μm, and the distance between adjacent openings 4 is 18 μm.

Subsequently, using this substrate 1 as a work, Ni plating was performed as in the first embodiment. Here again, the first plating layer 5 was grown until it became a hemispherical structure having a radius of the central portion of the array of about 10 μm. When the radius of the first plating layer 5 was about 10 μm at the center of the array, a hemispherical structure of the first plating layer 5 having a maximum radius of about 15 μm was formed at the periphery of the array.

Next, as in the first embodiment, the first mask layer 3 is formed.
Are removed, and 1064 × 8 at 8 locations excluding the array periphery
Selectively on the first plating layer 5 grown on the 08 regions and the positions corresponding to the alignment markers for each region (these are any of the first to third embodiments). The second mask layer 6 is provided. Here, there is almost no influence of the current density distribution due to the opening 4 provided for the alignment marker, and the first plating layer 5 in the area covered with the second mask layer 6 in the 1064 × 808 areas of the eight locations. The in-plane distribution of the diameter was within 5%.

Further, as in the first embodiment, the substrate 1 was used as a work, and using it as an anode, a Ni plating bath consisting of nickel sulfate, nickel chloride, boric acid and a brightener was used, and the bath temperature was 60 ° C. The exposed first plated layer 5 is electrolytically etched at a current density of 8 A / dm ² . The electrolytic etching was stopped when the first plating layer 5 made of Ni existing in the region not covered with the second mask layer 6 was consumed.

Next, as in the first embodiment, the second mask layer 6 is removed, so that 1064 × 808 are formed at eight locations.
Array of first plated layer 5 and alignment marker 8
Could be formed (FIG. 19). In FIG. 19, 10
Alignment markers 8 (indicated by dots) are formed on the left and right sides of each array of 64 × 808 first plating layers 5. At this time, the in-plane distribution of the radius of the first plating layer 5 in each region was within 5%. Further, since each alignment marker 8 is each marker of the first to third embodiments and the combination thereof,
Each has a different alignment marker.

Further, as in the first embodiment, the second plated layer 7 is formed. As a result, a mold for microlens array having a high gloss in which the first plating layer 5 was firmly fixed on the electrode layer 2 was obtained. Similar to the first embodiment, the radius of curvature of each plating layer in the diagonal direction and the horizontal direction is substantially equal, the average radius of curvature is 20 μm, and the distribution of the radius of curvature is ± 1.
It was possible to form a mold having a uniform shape with a size of less than μm. Furthermore, the in-plane distribution of the height of the plating layer in the eight microlens group regions and the plating layer in the alignment marker region was within 5%.

As described above, according to this embodiment, from one substrate,
Equipped with an alignment marker that achieves highly accurate alignment with a small in-plane distribution of the size of each lens
It has been possible to provide a method of manufacturing a mold for a microlens array of various kinds.

It is needless to say that the above-mentioned substrate can be used as a mold master for a microlens array to fabricate a mold for a microlens array and further a convex microlens array as in the first embodiment. That is, the mold is released from the substrate to form a mold for a microlens array, and then an ultraviolet curable resin is applied to the mold for the microlens array, and then a glass substrate to be a supporting substrate is placed thereon. . After being cured by ultraviolet irradiation, the resin is peeled off and cut off to manufacture a convex microlens array equipped with eight types of alignment markers from one die. These mylo lens arrays were equipped with alignment markers that realize highly accurate alignment, and the in-plane distribution of lens diameter was within 5%.

[0097]

As described above, according to the present invention,
Easy fabrication process, high controllability, small radius of curvature, and realization of microstructure array with small in-plane distribution in the array, more precise alignment, and cross-shaped alignment marker It was possible to realize a microstructure array mold capable of producing a microstructure array equipped with a possible alignment marker. Furthermore, the radius of curvature is small and the in-plane distribution in the array is small, achieving highly accurate alignment,
It has been possible to realize a microstructure array such as a microlens array equipped with an alignment marker that can also be applied to a cross-shaped alignment marker, and a manufacturing method thereof.

Further, it is possible to form a plurality of molds for a microstructure array such as a microlens array in which the variation in the size of the microstructure such as a lens is suppressed within one substrate surface. . Since the height of the apex of the microlens array and the height of the apex of the alignment marker obtained from these microlens array molds are in substantially the same plane and both come within the depth of focus of the lens system on the aligner side, Highly accurate alignment can be achieved. As a result, it is possible to improve the overlay accuracy with the TFT substrate and the like, improve the matching between the pixel portion and the microlens, and improve the pixel aperture ratio and the light collection rate of the microlens.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a manufacturing process of a mold for a microlens array according to a first embodiment of the present invention.

FIG. 2 is a top view of step (a) of FIG.

FIG. 3 is a top view of step (b) of FIG.

FIG. 4 is a top view of step (c) in FIG. 	

FIG. 5 is a top view of step (d) in FIG.

FIG. 6 is a top view of step (e) in FIG.

FIG. 7 is a top view of step (f) in FIG.

FIG. 8 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the second embodiment of the present invention.

FIG. 9 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the second embodiment of the present invention.

FIG. 10 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the second embodiment of the present invention.

FIG. 11 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the second embodiment of the present invention.

FIG. 12 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the third embodiment of the present invention.

FIG. 13 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the third embodiment of the present invention.

FIG. 14 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the third embodiment of the present invention.

FIG. 15 is a top view showing a part of the manufacturing process of the mold for the microlens array according to the third embodiment of the present invention.

FIG. 16 is a top view showing an alignment marker on the drive substrate side that is suitable for the first embodiment.

FIG. 17 is a top view showing an alignment marker on the drive substrate side suitable for the case of the second embodiment.

FIG. 18 is a top view showing an alignment marker on the drive substrate side suitable for the case of the third embodiment.

FIG. 19 is a top view schematically showing a mold for a microlens array according to a fourth embodiment of the present invention.

[Explanation of symbols]

1 substrate 2 electrode layers 3 First mask layer 4 openings 5 First plating layer 6 Second mask layer 7 Second plating layer 8 Alignment marker 9 pixels 10 Drive board side alignment marker

Claims (22)

(57) [Claims] 1. A substrate having a conductive portion is used, (1) a step of forming an insulating first mask layer on the conductive portion, (2) a desired microstructure on the first mask layer. Forming a plurality of microstructure openings at intervals corresponding to the array arrangement; (3) electroplating or electrodeposition using the conductive portion as a cathode through the openings and the first mask layer A step of forming a first plating layer or an electrodeposition layer thereon, (4) a suitable microstructure array area on the substrate and the first plating layer or electrodeposition layer and outside the microstructure array area. Forming a second mask layer on two or more adjacent first plating layer or electrodeposition layer regions at different positions (5) The first region of the region where the second mask layer is not formed. Remove the plating layer or electrodeposition layer by etching And (6) removing the second mask layer, which is a method for manufacturing a microstructure array, wherein a suitable position outside the desired microstructure array region in the step (4) is close to the appropriate position. A method for manufacturing a microstructure array, wherein the first plating layer or electrodeposition layer covered with two or more second mask layers is for forming an alignment marker. 2. The method for producing a microstructure array according to claim 1, further comprising (7) removing the first mask layer after the step (3). 3. Further, after the step (6), (8) forming a second plating layer or electrodeposition layer from the first plating layer or electrodeposition layer to the conductive portion or the first mask layer. The method for producing a microstructure array according to claim 1 or 2, further comprising: 4. The method for producing a microstructure array according to claim 1, wherein in the step (2), the opening is circular. 5. The method for producing a microstructure array according to claim 1, wherein in the step (2), the openings are arranged at equal intervals in the left-right direction and the up-down direction. 6. The method for producing a microstructure array according to claim 1, wherein in the step (5), the first plating layer is removed by electrolytic etching. 7. The method of manufacturing a microstructure array according to claim 3, wherein in the step (8), the second plating layer is formed by electroless plating. 8. A first plating layer or electrodeposition layer, or a first plating layer or electrodeposition layer and a first plating layer or electrodeposition layer formed at an appropriate position outside the microstructure array region, for the alignment marker. The method for producing a microstructure array according to any one of claims 1 to 7, wherein the microstructure array is an aggregate of substantially hemispherical structures consisting of the plating layer or electrodeposition layer of 2. 9. The method for producing a microstructure array according to claim 1, wherein the microstructure array is a mold for a microstructure array. 10. The method for producing a microstructure array according to claim 9, wherein the microstructure array die is a microlens array die. 11. An assembly of microstructures in which a structure for an alignment marker is formed outside a group of microstructures of a microstructure array, and the structure for the alignment marker comprises a substantially hemispherical plating layer or electrodeposition layer. A microstructure array characterized by the above. 12. The microstructure of the microstructure array is also a microstructure including the substantially hemispherical plating layer or electrodeposition layer.
The microstructure array according to. 13. The microstructure comprises a first plating layer or electrodeposition layer, or a first plating layer or electrodeposition layer and a second plating layer or electrodeposition layer formed on the first plating layer or electrodeposition layer. 2. A plating layer or an electrodeposition layer.
1. The microstructure array according to 1. 14. The microstructure array according to claim 11, 12 or 13, wherein the height of the microstructure group and the height of the microstructure of the alignment marker structure are substantially equal to each other. 15. The microstructure array according to claim 11, wherein the alignment marker structure formed of the aggregate includes a row of lines of the microstructure. 16. The microstructure array according to claim 15, wherein the alignment marker structure formed of the aggregate has a line of lines of the microstructure intersecting each other. 17. The microstructure array according to claim 11, wherein the alignment marker structure formed of the aggregate includes two lines of microstructure lines. 18. The microstructure array according to claim 17, wherein the alignment marker structure formed of the aggregate has two lines of microstructures intersecting each other. 19. The microstructure array according to any one of claims 11 to 18, which is a mold for a microstructure array. 20. The microstructure array according to claim 19, which is a mold for a microlens array. 21. A microstructure array configured as the microlens array according to any one of claims 11 to 18, or a microlens array produced by the mold for a microlens array according to claim 20, An image pickup device, wherein each microlens is mounted in alignment with each light receiving portion using the alignment marker. 22. A microstructure array configured as the microlens array according to any one of claims 11 to 18, or a microlens array produced by the mold for a microlens array according to claim 20, A display device in which each microlens is mounted in alignment with each pixel portion using the alignment marker.