JP2016109815A - Method for manufacturing microlens array substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel method for manufacturing a microlens array substrate on which microlens faces each with a concave surface are array-arranged.SOLUTION: A method for manufacturing a microlens array substrate includes: a thin film for mask formation step S1 for forming a thin film 12 for a mask on a formation surface on which an array arrangement of microlens faces is formed, of a substrate 10; an imprint resin layer formation step S2 for forming an imprint resin layer 14 on the thin film 12 for the mask; a patterning step S3 for patterning the imprint resin layer 14 using an imprint mold 16; a pattern boring step S4 for carrying out dry etching for the thin film 12 for the mask with an imprint resin layer 14A after patterning as the mask and boring an open array pattern; a wet etching step S5 for carrying out wet etching for the substrate 10 with a thin film 12A for a mask after boring as a mask and forming an array arrangement MLAS of microlens faces ML; and a removal step S6 for removing residues remaining after the wet etching step.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for manufacturing a microlens array substrate.

  A microlens array is an “optical element in which minute microlenses are arrayed one-dimensionally or two-dimensionally”, and one that is used in combination with a liquid crystal panel in a liquid crystal projector is well known.

  2. Description of the Related Art A microlens array is widely known in which two transparent plates having different refractive indexes are integrally superposed and the superposed boundary surface is an “array arrangement surface of microlens surfaces”.

  In this case, one transparent plate has an array of microlens surfaces with convex curved surfaces, and the other transparent plate has an array of microlens surfaces with concave curved surfaces.

  Each microlens surface having a convex curved surface and each microlens surface having a concave curved surface are fitted in a one-to-one manner without gaps to form a microlens.

  Among these transparent plates having an array arrangement of microlens surfaces, a plate having a concave surface is called a “microlens array substrate”.

  As a method of manufacturing a microlens array substrate having such a “concave curved microlens surface” array, a method of performing wet etching using a mask is known (Patent Document 1, etc.).

  That is, a mask is formed on a substrate on which an array arrangement of “microlens surfaces with concave surfaces” is formed, and an array arrangement of openings corresponding to the array arrangement of the microlens surfaces is formed on the mask.

  Then, the substrate is wet-etched through a mask formed with an “array of openings” to form a concave curved surface that becomes a microlens surface.

  Conventionally, a photolithography technique using laser light is well known as a method for obtaining a mask in which an array of openings is formed.

  That is, a layer to be a mask is formed as a “photoresist layer”, a pattern of “array of openings” is exposed and drawn by laser light, and developed to form an array of openings.

  In recent years, liquid crystal projectors have become higher in definition of projected images, and accordingly, microlenses of a microlens array combined with a liquid crystal panel are further miniaturized, and the density of the array arrangement is also increasing.

  In order to cope with such a situation satisfactorily, “laser light having a wavelength in the ultraviolet region” is required to draw “an array array of finer openings in the photoresist layer to be a mask”.

  On the other hand, imprint technology has recently advanced, and fine imprint processing such as nanoimprint technology has become possible.

  Although it is also known that a fine surface shape is directly formed by imprinting (Patent Document 2), the manufacture of an imprint mold for realizing “array arrangement of microlens surfaces by fine concave curved surfaces” It is not always easy.

  An object of the present invention is to realize a novel manufacturing method of a microlens array substrate in which microlens surfaces with concave curved surfaces are arrayed.

  The microlens array manufacturing method of the present invention is a method of manufacturing a microlens array substrate in which microlens surfaces with concave curved surfaces are arrayed, and on a forming surface that forms an array of microlens surfaces of a wet-etchable substrate, A mask thin film forming step for forming a mask thin film using a material that can be dry-etched, and an imprint resin layer forming step for forming an imprint resin layer on the formed mask thin film using an imprint resin, and A patterning step of patterning the imprint resin layer with an imprint mold having a protrusion arrangement corresponding to the arrangement pattern of the microlens surface, and dry etching with respect to the mask thin film using the patterned imprint resin layer as a mask The micro lens surface A pattern perforation process for perforating an opening array pattern corresponding to the array pattern, and a wet etching process for performing wet etching on the substrate using the mask thin film perforated with the opening array pattern as a mask to form an array array of microlens surfaces And a removing step for removing the residue after the wet etching step.

  According to the present invention, a novel manufacturing method of a microlens array substrate in which microlens surfaces with concave curved surfaces are arranged in an array can be realized.

It is a figure for demonstrating the process of a micro lens array board | substrate manufacturing method. It is a figure for demonstrating the micro lens array board | substrate manufacturing method. It is a figure for demonstrating a response | compatibility with the array arrangement | sequence of a micro lens, and an imprint type | mold.

Embodiments of the invention will be described below.
FIG. 1 is a diagram for explaining the steps of the microlens array manufacturing method.

  The microlens array manufacturing method has six steps S1 to S6.

  Step S1 performed first after the start is a “mask thin film forming step”.

  The “mask thin film forming step” is a step of forming a mask thin film using a material that can be dry etched on a forming surface that forms an array arrangement of microlens surfaces of a wet-etchable substrate.

  In step S2, an “imprint resin layer forming step” is performed.

  The “imprint resin layer forming step” is a step of forming an imprint resin layer on the mask thin film formed in step S1 using an imprint resin.

  In step S3, a “patterning step” is performed.

  The “patterning step” is a step of patterning the imprint resin layer formed in step S2 by “an imprint mold having a protrusion arrangement corresponding to the arrangement pattern of the microlens surface”.

  In step S4, a “pattern drilling step” is performed.

  The “pattern drilling step” is a step of performing dry etching on the mask thin film using the imprint resin layer patterned in step S3 as a mask to punch an opening array pattern corresponding to the array pattern on the microlens surface.

  In step S5, a “wet etching process” is performed.

  The “wet etching process” is a process of forming an array arrangement of the microlens surface by performing wet etching on the substrate using the mask thin film in which the opening arrangement pattern is perforated in step S4 as a mask.

  In step S6, a “removal step” is performed.

  The “removal process” is a process of removing the residue after the wet etching process in step S5.

Hereafter, each said process is demonstrated with reference to FIG.
In FIG. 2A, reference numeral 10 denotes a “substrate”. In the example in the description, an “array arrangement of microlens surfaces with concave curved surfaces” is formed on the upper surface of the substrate 10.

  The substrate 10 is made of a transparent material and can be wet etched by the “wet etching process” in step S5.

  An example of the material of the substrate 10 is “quartz”. Hereinafter, the substrate 10 is described as a quartz substrate and is referred to as a quartz substrate 10.

  FIG. 2B shows a state in which the mask thin film 12 is formed on the surface of the quartz substrate 10 on which the “array arrangement of microlens surfaces with concave curved surfaces” is formed, that is, the state after the “mask thin film forming step”. ing.

  The mask thin film 12 satisfies the condition that it is not eroded by the etchant during the “wet etching process” performed in step S5 and is dry-etched in the “pattern drilling process” performed in step S4. Formed of material.

  When wet etching is performed on the quartz substrate 10, an “hydrofluoric acid type” etching solution is generally used. In this case, the mask thin film material is resistant to the hydrofluoric acid etching solution. Specifically, for example, a metal such as Cr, Si, Ti, Au, polysilicon, silicon nitride, or the like can be suitably used.

  FIG. 2C shows the state after the “imprint resin layer forming step” in step S 2, and the imprint resin layer 14 is formed on the mask thin film 12.

  Various types of known imprint resins can be used as appropriate.

  The imprint resin layer 14 must function as a mask for dry etching when the “pattern drilling step” in step S4 is performed by dry etching.

  Therefore, a material that is resistant to dry etching is selected.

  As an example of the imprint resin, a “photo curable” or “thermo curable” resin can be used as a liquid and formed into a resin layer having an appropriate thickness by a method such as spin coating.

  2D to 2F are views for explaining the “patterning step”, and reference numeral 16 denotes an imprint type.

  As shown in FIG. 2D, the imprint mold 16 has an array of minute protrusions 16B formed on one surface of a plate-like substrate portion 16A.

  The “projection array” that is the array of the protrusions 16B is an array corresponding to the array pattern of the microlens surface.

  As shown in FIG. 2E, the arrangement of the protrusions 16 </ b> B of the imprint mold 16 is pressed against the imprint resin layer 14, and the protrusions 16 </ b> B penetrate into the layer of the imprint layer 14.

  At this time, as shown in the figure, the tip of the protrusion 16B is made to reach the mask thin film 12.

  Thereafter, the imprint resin layer 14 is cured by the action of light or heat, and the imprint mold 16 is “die-cut”. If necessary, a “release agent” or the like is applied to the imprint mold 16 so that the mold can be easily removed.

  FIG. 2 (f) shows a state after die cutting. The above is the “patterning step”.

  As described above, when the imprint mold 16 is pressed against the imprint resin layer 14 in the patterning step, the tip of the protrusion 16B reaches the mask thin film 12.

  Therefore, the surface of the mask thin film 12 is “exposed” at the bottom of the hole formed in the imprint resin layer 14 by the protrusion 16B after the die is cut.

  In FIG. 2F, the implant resin layer patterned by the implant mold 16 is indicated by reference numeral 14A.

  Subsequent to the patterning step, dry etching is performed on the portion of the “exposed mask thin film” using the patterned imprint resin layer 14A as a mask.

  By this dry etching, the “exposed thin film portion for mask” is removed, and a hole is formed as an “opening”. The arrangement pattern of the openings follows the projection arrangement of the projections 16B.

  Therefore, by “dry etching”, an “opening array” that matches the protrusion array is punched as an opening array pattern.

  The above is the “pattern drilling step”.

  Subsequently, a “wet etching process” is performed, and the quartz substrate 10 is wet-etched using a hydrofluoric acid-based etching solution with the mask thin film having a perforated opening array pattern as a mask, and the array arrangement of the microlens surface is formed. Form.

  FIG. 2G shows a state after the wet etching process.

  In this figure, the reference numeral 12A indicates "a thin film for a mask having a perforated aperture pattern".

  When the wet etching process is performed, the etching solution wet-etches the quartz substrate 10 through each opening of the opening array pattern drilled in the mask thin film 12A.

  By this wet etching process, as shown in FIG. 2G, an array arrangement of microlens surfaces ML having a concave curved surface is formed.

  After the wet etching process, a “removal process” is performed to remove residues of the mask thin film 12A and the imprint resin layer 14A.

  After this “removal step”, a microlens array substrate MLA on which “an array array surface MLAS of the microlens surfaces ML with concave surfaces” is formed as shown in FIG.

  The “array arrangement of the microlens surface” in the microlens array substrate is one-dimensional or two-dimensional. In the manufacturing method of the present invention, one-dimensional arrangement or two-dimensional arrangement is possible.

  FIG. 3A shows a dense array as an example of a two-dimensional array of microlens surfaces ML. Each microlens surface ML is circular, and the lens surface shape is a “concave surface”.

  FIG. 3B shows the arrangement of the protrusions IP formed in the imprint mold.

  The two-dimensional array of protrusions IP corresponds to the two-dimensional array of microlens surfaces ML in a consistent manner. As shown in the figure, one protrusion IP corresponds to the center of each microlens surface ML to be formed. Arranged.

  In the example of FIG. 3B, the shape of the imprint-type protrusion IP is “a circular column with a circular cross section”. However, the shape of the protrusion is not limited to this, and the cross-sectional polygon (a triangle or a quadrangle, n (≧ 5) polygon).

  That is, it is sufficient if a small opening can be drilled, and the shape is appropriate.

  Further, the protrusion shape is not limited to the cylindrical shape or the polygonal column shape, and may be a cone shape, a cone shape such as a triangular pyramid shape or a quadrangular pyramid shape. When the cone-shaped protrusion is used, a “smaller opening” can be drilled in the mask thin film.

  The microlens array substrate manufactured as described above is integrated with another substrate having a convex curved array array that fits in alignment with the formed concave microlens surface and becomes a microlens surface. A lens array "can be constructed.

  Such a microlens array can be used in combination with a liquid crystal panel in a liquid crystal projector, but of course is not limited to such applications.

  The “concave surface” of the microlens surface formed by the wet etching process is a “continuous concave surface”.

  The “concave surface shape” depends on the material and thickness of the mask thin film, the size and shape of the opening (circular, elliptical, square, rectangular, polygonal, etc.) and the conditions for wet etching (etching solution). It is possible to realize various surface shapes such as a spherical surface and a spheroid surface.

  As described above, according to the present invention, the following “microlens array substrate” manufacturing method can be realized.

[1]
A method of manufacturing a microlens array substrate MLA in which microlens surfaces ML with concave curved surfaces are arrayed, and a mask made of a material that can be dry-etched on a formation surface that forms an array of microlens surfaces of a substrate 10 that can be wet etched Thin film forming step S1 for forming the thin film 12 for mask, imprint resin layer forming step S2 for forming the imprint resin layer 14 on the formed thin film 12 for mask with the imprint resin, and the formed imprint A patterning step S3 of patterning the printed resin layer 14 with an imprint mold 16 having a protrusion arrangement corresponding to the arrangement pattern of the microlens surface ML, and the patterned thin film for mask using the patterned imprint resin layer 14A as a mask 12 is dry-etched before A pattern drilling step S4 for drilling an aperture array pattern corresponding to the array pattern of the microlens surface ML, and the substrate 10 is wet-etched using the mask thin film 12A perforated with the aperture array pattern as a mask, and the microlens surface ML A method of manufacturing a microlens array substrate MLA, comprising: a wet etching step S5 for forming the array arrangement MLAS of FIG. 5; and a removing step S6 for removing a residue after the wet etching step.

[2]
[1] In the method for manufacturing a microlens array substrate according to [1], a quartz substrate 10 is used as a substrate, a mask thin film 12 is formed of a material resistant to a hydrofluoric acid etching solution, and the hydrofluoric acid etching is performed. A method of manufacturing a microlens array substrate, which performs a wet etching process with a liquid.

[3]
[2] The method for manufacturing a microlens array substrate according to [2], wherein Cr, Si, Ti, Au, silicon nitride, or polysilicon is used as a material for the mask thin film.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the specific embodiments described above, and the invention described in the claims unless otherwise specified in the above description. Various modifications and changes are possible within the scope of the above.
The effects described in the embodiments of the present invention are merely a list of suitable effects resulting from the invention, and the effects of the present invention are not limited to those described in the embodiments.

10 Substrate (quartz substrate)
12 Thin film for mask
14 Imprint resin layer
16 Imprint type
16B Imprint substrate part 16A Protrusion formed on imprint mold
12A Mask substrate after pattern drilling
14A Imprint resin layer after patterning process

Japanese Patent No. 4193265 JP 2010-13337 A

Claims (3)

A method of manufacturing a microlens array substrate in which microlens surfaces with concave curved surfaces are arrayed,
A thin film forming process for a mask that forms a thin film for a mask with a material that can be dry-etched on a forming surface that forms an array of microlens surfaces of a wet-etchable substrate;
An imprint resin layer forming step of forming an imprint resin layer on the formed mask thin film with an imprint resin;
A patterning step of patterning the formed imprint resin layer with an imprint mold having a protrusion arrangement corresponding to the arrangement pattern of the microlens surface;
Using the patterned imprint resin layer as a mask, performing a dry etching on the mask thin film, and perforating an opening array pattern corresponding to the array pattern of the microlens surface; and
A wet etching step of performing wet etching on the substrate using a mask thin film having a perforated aperture array pattern as a mask to form an array array of microlens surfaces; and
A removal step of removing the residue after the wet etching step;
A method for manufacturing a microlens array substrate, comprising: In the manufacturing method of the micro lens array substrate according to claim 1,
A method of manufacturing a microlens array substrate, wherein a quartz substrate is used as a substrate, a thin film for a mask is formed from a material resistant to a hydrofluoric acid-based etching solution, and a wet etching process is performed with the hydrofluoric acid-based etching solution. In the manufacturing method of the micro lens array substrate according to claim 2,
A method of manufacturing a microlens array substrate using Cr, Si, Ti, Au, silicon nitride, polysilicon as a material for a thin film for a mask.

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