JP2010120283A - Microlens mold manufacturing method, and microlens mold original plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microlens mold manufacturing method capable of forming properly curved face structure of a microlens. <P>SOLUTION: A resin is coated onto a substrate with an irregular pattern, and a metal layer is laminated in a side coated with the resin by electroforming, in this microlens mold manufacturing method. The resin is not film-formed flatly, when the resin is film-formed onto the substrate with the irregular pattern, to be film-formed into a mountainous wave form on the irregular pattern. The curved face structure is formed thereby corresponding to the irregular pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a microlens mold and a microlens mold master.

In recent years, microlenses and microlens arrays have been used for a wide range of applications as optical elements.
For example, there are applications such as a member for an image display device (liquid crystal, projection, etc.), an image sensor, a condensing means of an optical pickup such as a liquid crystal projector or a compact disk.

  As a method for creating such a microlens, a microlens mold having a desired microlens shape is prepared, and a microlens is manufactured by performing transfer processing molding using the microlens mold. It has been known.

For example, a method of manufacturing a microlens mold using cutting has been proposed (see Patent Document 1).
JP 2002-205310 A

However, when a microlens mold is manufactured by grinding, machining traces after machining remain in the manufactured microlens mold.
For this reason, the remaining processing marks affect the optical performance and shape transferability, which is not preferable.

  Accordingly, the present invention has been made to solve the above-described problems, and an object thereof is to provide a microlens mold manufacturing method capable of suitably forming a curved surface structure of a microlens.

  The present invention according to claim 1 includes a step of forming a concavo-convex pattern on a substrate, a step of coating a resin on the side of the substrate on which the concavo-convex pattern is formed, and the resin of the substrate being coated. A microlens mold manufacturing method comprising: a step of laminating a metal layer on a side; and a step of peeling the substrate and the metal layer.

  The present invention described in claim 2 is the microlens mold manufacturing method according to claim 1, further comprising a step of peeling the resin from the substrate on which the concave / convex pattern is formed, and again the concave / convex pattern on the substrate. A step of coating a resin on the side where the metal layer is formed, a step of laminating a metal layer on the resin side again by electroforming, and a step of peeling the metal layer and the substrate again. A microlens mold manufacturing method characterized by the above.

  The present invention according to claim 3 is the microlens mold manufacturing method according to claim 1 or 2, wherein the resin on the substrate is fluidized in the step of peeling the metal layer and the substrate. A microlens mold manufacturing method characterized by the above.

  A fourth aspect of the present invention is the microlens mold manufacturing method according to any one of the first to third aspects, wherein an upper surface figure of a convex portion of the concavo-convex pattern is a quadrangle, and the convex portion is a square lattice arrangement. A method for producing a microlens mold, wherein

  The present invention according to claim 5 is the microlens mold manufacturing method according to any one of claims 1 to 3, wherein the top surface of the convex portion of the concave-convex pattern is a hexagon, and the convex portion is arranged in a honeycomb arrangement. A method for producing a microlens mold, wherein

  The present invention according to claim 6 includes a substrate on which a concavo-convex pattern is formed and a resin laminated on the concavo-convex pattern forming side of the substrate, and the resin surface has a curved structure of a microlens. It is the microlens mold original plate characterized by the above-mentioned.

  In the microlens mold manufacturing method of the present invention, a resin is coated on a substrate on which a concavo-convex pattern is formed, and a metal layer is laminated on the side coated with the resin. When a resin is formed on a substrate having a concavo-convex pattern, the resin is not formed flat, but is formed in a mountain pattern on the convex pattern. For this reason, the curved surface structure according to the uneven | corrugated pattern can be formed. Further, since the curved surface structure formed at this time is determined by the concavo-convex pattern and the surface tension of the resin, there is no processing mark or the like on the curved surface.

  Hereinafter, the microlens mold manufacturing method of the present invention will be specifically described.

<Process for forming concave / convex pattern on substrate>
First, an uneven pattern is formed on the substrate.

The substrate is not particularly limited as long as it has physical properties / mechanical properties suitable for the microfabrication technique used for forming the uneven pattern.
For example, (1) a substrate containing SiO ₂ such as quartz, glass, (2) a sapphire substrate, (3) a silicon substrate, (4) a substrate containing negatively expandable manganese nitride, (5) a silicon carbide substrate, ( 6) A glassy carbon substrate, (7) a metal substrate such as nickel, tantalum, or chromium may be used. Further, it may be a laminated substrate in which a plurality of materials are laminated.

The concavo-convex pattern may be a pattern having a step, and may be appropriately designed according to specifications.
Moreover, you may design the upper surface figure of an uneven | corrugated pattern suitably according to a specification. For example, it may be a circular shape, a polygonal shape, or a star shape having an arbitrary number of vertices and connecting the vertices with continuous straight lines or curves.

Moreover, it is preferable that the concavo-convex pattern has an array pattern. By providing an array-like pattern, a microlens mold capable of suitably producing a microlens array can be formed.
The array shape indicates a state in which the unit lens patterns are regularly arranged, and includes, for example, patterns such as a grid pattern (square lattice arrangement) and a honeycomb pattern (honeycomb arrangement).

  When the upper surface figure of the convex part of the concavo-convex pattern is a quadrangle, the convex part is preferably arranged in a square lattice arrangement. At this time, a square pattern can be filled in a plane, and a microlens mold for a microlens array can be suitably manufactured.

  When the upper surface figure of the convex part of the concavo-convex pattern is hexagonal, the convex part is preferably arranged in a honeycomb arrangement. At this time, a hexagonal pattern can be planarly filled, and a microlens mold for a microlens array can be suitably manufactured.

  As a method for forming the concavo-convex pattern, a fine processing technique capable of forming a desired pattern dimension width and pattern shape may be used. For example, as a fine processing technique, a lithography method, an etching method, a fine machining method (laser processing, machining processing, or the like) may be used.

<Step of coating resin>
Next, a resin is coated on the substrate from the side where the uneven pattern is formed.
When the resin is coated on the substrate having the concavo-convex pattern, the resin is not coated flat, and is coated in a mountain pattern on the convex pattern according to the level difference of the concavo-convex pattern. For this reason, it is possible to form a curved surface structure corresponding to the uneven pattern in a self-aligning manner. Further, since the curved surface structure formed at this time is determined by the concavo-convex pattern and the surface tension of the resin, there is no processing mark or the like on the curved surface.

The resin may be any material that has (1) fluidity and (2) cures under external conditions (conditions such as heat, pressure, and light).
For example, as the resin, a thermoplastic resin that changes hardness by heat, a thermosetting resin that cures by heat, or a photosensitive resin that cures by exposure light may be used.
For example, specifically, a novolac resin, a polystyrene resin, a PMMA resin, or the like may be used.

  In addition, as a resin coating method, a known thin film forming technique may be appropriately used depending on the material. For example, a die coating method, a spin coating method, a spray coating method, a slit coating method, a dip coating method, or the like may be used.

  The film thickness of the resin may be determined as appropriate in consideration of physical properties such as the viscosity and composition of the resin used, depending on the desired curved surface structure. In addition, the resin thickness suitable for the desired curved surface structure may be calculated by simulation using a computer (Monte Carlo method or the like).

<Process of laminating metal layers by electroforming>
Next, a metal layer is laminated on the coated resin by electroforming.

Electroforming may be performed by a known method as appropriate. For example, specifically, electroforming using Ni may be performed.
Further, when performing electroforming, a seed layer may be formed on the resin surface on which the curved surface structure is formed. A metal thin film may be used as the seed layer.

<Step of peeling the metal layer and the substrate>
Next, the substrate and the metal layer are peeled off to obtain a microlens mold made of the metal layer.
The peeling method is not particularly limited, and a method of dissolving the original plate side by wet etching, a method of peeling by applying physical force, or the like may be used.

In the microlens mold manufacturing method of the present invention, it is preferable to fluidize the resin on the substrate in the step of peeling the metal layer and the substrate. Thereby, the adhesiveness between a metal layer and resin falls, a metal layer and a board | substrate can be peeled suitably and it can suppress that a board | substrate and a metal layer lose | deviate at the time of peeling. In particular, when a metal layer is laminated by electroforming, the resin and the metal layer are in close contact with each other along the shape, so that peeling while maintaining the transferred shape is difficult, and the effect of fluidizing the resin is great. It is.
The fluidizing method may be appropriately performed according to the resin used. For example, a method of (1) selectively dissolving only the resin by wet etching, or (2) heating when a thermoplastic resin is used may be used.

  The microlens mold manufacturing method of the present invention further includes a step of peeling the resin from the substrate on which the concavo-convex pattern is formed, and a step of coating the resin on the side on which the concavo-convex pattern is formed again. It is preferable that the method further includes a step of laminating a metal layer on the resin side by electroforming and a step of peeling the metal layer and the substrate again. The curved surface structure can be reproduced any number of times by applying resin to the substrate on which the concavo-convex pattern is formed again. Therefore, the microlens mold consisting of the metal layer from the substrate on which the single concavo-convex pattern is formed. Can be obtained. Thereby, a plurality of microlens molds can be manufactured with high accuracy.

<Example 1>
Hereinafter, as an example of the method for manufacturing a microlens mold of the present invention, a specific description will be given with reference to FIG.

First, resist 1 was coated on substrate 2 to a thickness of 20 μm (FIG. 1A).
At this time, a positive resist for g-line (trade name: PMER LA900 / manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used as the resist 1.
A 6-inch quartz substrate was used as the substrate 2.

Next, a 20 μm square dot pattern was exposed with a laser drawing machine, and a resist pattern 3 was formed with an alkali developer (tetramethylammonium hydroxide, 3.0 wt%).
At this time, the exposure conditions were an exposure amount of 2200 mJ / cm ² and a development time of 600 seconds.

Next, the substrate 2 was etched using an etching gas 4 using the formed resist pattern 3 as a mask (FIG. 1B).
At this time, dry etching using an ICP dry etching apparatus was used as etching.
Etching conditions of the quartz substrate as the substrate 2 are CF ₄ flow rate 20 sccm, O ₂ flow rate 10 sccm, Ar flow rate 50 sccm, pressure 10 mTorr, ICP power 300 W, RIE power 500 W, and etching from the substrate surface to a depth of 20 μm. Went.

Next, the resist 1 remaining by O ₂ plasma ashing was peeled and washed to obtain a substrate 5 having an uneven pattern (FIG. 1C).
At this time, the O ₂ plasma ashing conditions were an O ₂ flow rate of 500 sccm, a pressure of 30 Pa, and an RF power of 1000 W.

Next, a resin 6 having a viscosity of 100 cp was spin-coated on the substrate 5 having a concavo-convex pattern at a rotation speed of 2000 rpm, and heated to dry and fix the resin 6 (FIG. 1D).
At this time, the resin 6 was not applied with a uniform film thickness on the substrate surface, but formed a curved surface structure in a self-aligned manner according to the steps of the concavo-convex pattern. As the resin 6, a novolac resin was used.

  Next, the surface of the coated resin 6 side was treated with potassium permanganate, and Ni was electrocast using a Pd—Sn catalyst solution to form a metal layer 7 (FIG. 1 (e)).

Next, the metal layer 7 was peeled from the substrate 5 having the concavo-convex pattern to obtain a microlens mold 8 (FIG. 1 (f)).
At this time, the resin 6 was dissolved using NMP (N-methyl-2-pyrrolidone) at the time of peeling.

  From the above, the microlens mold 8 was able to be manufactured.

<Example 2>
In Example 1, after manufacturing the microlens mold 8, the substrate 5 having the concavo-convex pattern was washed, and the resin coating, electroforming, and peeling of the metal layer were performed again.
At this time, a mixed solution of hydrogen peroxide and sulfuric acid was used for cleaning the substrate 5 having the uneven pattern.
The resin coating, electroforming, and metal layer peeling were performed under the same conditions as in Example 1.

  As mentioned above, the microlens mold provided with the pattern of the same shape as Example 1 was able to be manufactured.

The method for producing a microlens mold of the present invention is expected to be used not only for producing a microlens mold but also for a wide range of fields in which it is required to form a fine curved surface structure pattern.
For example, semiconductor devices, optical elements, wiring circuits, data storage media (hard disks, optical media, etc.), medical materials (analysis test chips, microneedles, etc.), bio devices (biosensors, cell culture substrates, etc.), precision testing Applications such as equipment members (inspection probes, sample holding members, etc.), display panels, panel members, energy devices (solar cells, fuel cells, etc.), microchannels, microreactors, MEMS devices, imprint molds, photomasks, etc. It is done.

It is sectional process drawing which shows an example of implementation of the microlens mold manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Resist 2 ... Board | substrate 3 ... Resist pattern 4 ... Etching gas 5 ... Substrate with uneven pattern 6 ... Resin 7 ... Metal layer 8 ... Micro lens mold

Claims (6)

Forming an uneven pattern on the substrate;
Coating the resin on the side of the substrate on which the concave / convex pattern is formed;
Laminating a metal layer on the side of the substrate coated with the resin;
Peeling the substrate and the metal layer;
A method of manufacturing a microlens mold, comprising: The microlens mold manufacturing method according to claim 1,
Furthermore,
Removing the resin from the substrate on which the concavo-convex pattern is formed;
Again, coating the resin on the side of the substrate on which the concave / convex pattern is formed,
Again, a step of laminating a metal layer by electroforming on the resin side,
Again, the step of peeling the metal layer and the substrate,
A method of manufacturing a microlens mold, comprising: A microlens mold manufacturing method according to claim 1 or 2,
A method for producing a microlens mold, wherein the resin on the substrate is fluidized in the step of peeling the metal layer and the substrate. A microlens mold manufacturing method according to any one of claims 1 to 3,
The top surface figure of the convex part of the concavo-convex pattern is a rectangle,
The method for producing a microlens mold, wherein the convex portions are arranged in a square lattice arrangement. A microlens mold manufacturing method according to any one of claims 1 to 3,
The top surface figure of the convex part of the concavo-convex pattern is a hexagon,
The method for producing a microlens mold, wherein the convex portions are arranged in a honeycomb arrangement. A substrate on which a concavo-convex pattern is formed;
And a resin laminated on the concave / convex pattern forming side of the substrate, wherein the resin has a curved surface structure of a microlens.

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