JP6314404B2 - Method for producing conductive mesh sheet and photomask - Google Patents

Description

  The present invention relates to a method for producing a conductive mesh sheet including a transparent substrate and a conductive mesh provided on the transparent substrate, and a photomask used in the method for producing a conductive mesh.

  Conventionally, a conductive mesh sheet including a transparent substrate and a conductive mesh provided on the transparent substrate has been widely used in various fields. As a widely known use of such a conductive mesh sheet, an electromagnetic wave shielding material (electromagnetic wave shielding sheet), a touch panel sensor, and a heating element disclosed in Patent Documents 1 and 2 can be exemplified. In such applications, the conductive mesh forms a mesh pattern that defines an open area on a transparent substrate, and exhibits various functions due to its material properties, such as conductivity and thermal conductivity. Expected.

  Some of such conductive meshes have a connection element that defines an opening region and a fracture portion between the connection elements. In recent years, a conductive mesh that has been miniaturized has been demanded.

JP 2004-192093 A JP 2006-344163 A

  As described above, the shape of the conductive mesh is required to be fine in recent years. In this case, the fractured portion between the connecting elements is also required to be fine.

  In general, a conductive mesh is formed by forming a resist pattern on a conductive metal film and performing etching through the resist pattern. In order to shorten the length of the break between connecting elements, this break It is necessary to remove the resist pattern corresponding to the above.

  On the other hand, in the exposure operation when forming a resist pattern, there is a problem that it is difficult to remove the resist pattern corresponding to a small fracture portion due to a resolution limit problem.

  The present invention has been made in consideration of such points, and has a connection element and a fracture portion between the connection elements, and a conductive mesh capable of accurately producing a conductive mesh having a fine shape. It aims at providing the photomask used for the manufacturing method of a sheet | seat, and the manufacturing method of an electroconductive mesh sheet.

  The present invention relates to a method for producing a conductive mesh sheet comprising a transparent substrate and a conductive mesh provided on the transparent substrate, a step of preparing the transparent substrate, and a conductive metal film on the transparent substrate. Forming a resist pattern on the conductive metal film, and etching the conductive metal film from above the resist pattern using an etching solution, thereby forming a fracture portion between the connection element and the connection element. A resist pattern having a connection element portion corresponding to the connection element and a break portion connected to the connection element portion and corresponding to the break portion, and the break portion is formed on the connection element portion. In contrast, the present invention provides a method for producing a conductive mesh sheet, which is formed by providing notches on both sides.

In the present invention, when the line width of the connecting element is w and the length of the fracture portion between the connecting elements is L,
0.1 <L / w <1
This is a method for producing a conductive mesh sheet.

In the present invention, when the line width w of the connecting element and the depth inward of each notch are a,
0.05 <a / w <0.45
This is a method for producing a conductive mesh.

  The present invention relates to a resist pattern used when forming a conductive mesh having a connecting element and a rupture portion between the connecting elements by etching the conductive metal film on the transparent substrate through the resist pattern. In the photomask for manufacturing, the resist pattern has a connection element portion corresponding to the connection element and a break portion connected to the connection element portion and corresponding to the break portion, and the break portion is notched from both sides with respect to the connection element portion. The photomask has a mask portion in which openings corresponding to connection element portions and fracture portions of the resist pattern are formed.

  The present invention relates to a resist pattern used when forming a conductive mesh having a connecting element and a rupture portion between the connecting elements by etching the conductive metal film on the transparent substrate through the resist pattern. In the photomask for manufacturing, the resist pattern has a connection element portion corresponding to the connection element and a break portion connected to the connection element portion and corresponding to the break portion, and the break portion is notched from both sides with respect to the connection element portion. The photomask has a mask portion having a shape corresponding to the connecting element portion and the fracture portion of the resist pattern.

In the present invention, when the line width of the connecting element is w and the length of the fracture portion between the connecting elements is L,
0.1 <L / w <1
The photomask is characterized by the following.

In the present invention, when the line width of the connecting element is w and the depth toward the inside of each notch is a,
0.05 <a / w <0.45
The photomask is characterized by the following.

  As described above, according to the present invention, it is possible to accurately produce a conductive mesh having a fine shape.

Drawing 1 (a)-(e) is a figure for explaining one embodiment of the present invention, and is a top view showing the manufacturing method of an electroconductive mesh sheet. 2A to 2F are cross-sectional views showing a method for producing a conductive mesh sheet. FIG. 3 is a perspective view showing a conductive mesh sheet. 4A and 4B show a photomask. FIG. 5 is a view showing a state in which a portion corresponding to a broken portion of the resist pattern is removed.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings other than the photographs attached to the present specification, for the sake of illustration and ease of understanding, the scale and the vertical / horizontal dimensional ratio are appropriately changed and exaggerated from those of the actual ones.

  In the present specification, the terms “sheet”, “plate”, and “film” are not distinguished from each other only based on the difference in names. For example, the “sheet” is a concept including a member that can be called a plate or a film, and cannot be distinguished only by a difference in name.

  In addition, “sheet surface (plate surface, film surface)” means a target sheet-like member (plate-like) when the target sheet-like (plate-like, film-like) member is viewed as a whole and globally. It refers to the surface that coincides with the plane direction of the member or film-like member. In the present embodiment, the sheet surface of the conductive film sheet and the sheet surface of the transparent substrate included in the conductive film sheet are parallel to each other.

  Furthermore, as used in this specification, the shape and geometric conditions and the degree thereof are specified. For example, terms such as “parallel”, “orthogonal”, “identical”, length and angle values, etc. Without being bound by meaning, it should be interpreted including the extent to which similar functions can be expected.

<<< Conductive Mesh Sheet >>>
As shown in FIG. 3, the conductive mesh sheet 10 includes a transparent base material 20 and a conductive mesh 15 provided on the transparent base material 20.

  When such a conductive mesh sheet 10 is observed from the conductive mesh 15 side, the conductive mesh 15 is observed in a metal color depending on its constituent material.

  Hereinafter, the transparent base material 20 and the conductive mesh 15 which are components of the conductive mesh sheet 10 will be described in order.

  In the present specification, “transparent” means that the visible light transmittance is (numerical value)% or more. The visible light transmittance referred to in this specification is a material having a thickness of 1 μm formed on a PET film (product number: Cosmo Shine A4300, thickness 100 μm) made by Toyobo Co., Ltd. Film is specified as an average value of transmittance at each wavelength when measured within a measurement wavelength range of 380 nm to 780 nm using a spectrophotometer (“UV-3100PC” manufactured by Shimadzu Corporation, JISK0115 compliant product) Is done.

<< Transparent substrate >>
As the transparent substrate 20, a known transparent substrate can be appropriately selected and used, and is not particularly limited. Examples of the material used for the transparent substrate 20 include a transparent resin and a transparent inorganic material. Examples of the transparent resin include acetyl cellulose resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, olefin resins such as polyethylene and polymethylpentene, acrylic resins, polyurethane resins, and polyethers. Examples include sulfone, polycarbonate, polysulfone, polyether, polyetherketone, acrylonitrile, methacrylonitrile, cycloolefin polymer, and cycloolefin copolymer. On the other hand, examples of the transparent inorganic material include glass such as soda glass, potash glass, and lead glass, ceramics such as PLZT, quartz, and fluorite.

  Although the thickness of the transparent base material 20 can be suitably set according to the use of the electroconductive mesh sheet 10, it is not specifically limited, Usually, it is 20-5000 micrometers, and the transparent base material 20 is supplied with the form of a roll. It may be any of those that do not bend to the extent that they can be wound, but that can be bent by applying a load, or those that do not bend completely.

  The configuration of the transparent substrate 20 is not limited to a configuration composed of a single layer, and may have a configuration in which a plurality of layers are laminated. When it has the structure by which the several layer was laminated | stacked, the layer of the same composition may be laminated | stacked, and the several layer which has a different composition may be laminated | stacked.

<< Conductive mesh >>
Next, the conductive mesh 15 will be described. The conductive mesh 15 is provided on the transparent substrate 20. In the example shown in FIG. 3, the conductive mesh 15 is patterned on the transparent substrate 20. In particular, in the example shown in FIG. 3, the conductive mesh 15 forms a mesh pattern that defines the opening region 15 c on the transparent substrate 20. That is, the conductive mesh 15 is formed by a large number of connecting elements 15a extending from the branch point 15d. Each opening region 15c is defined by being surrounded by three or more connection elements 15a. In the example shown in FIG. 3, the conductive mesh 15 forms a mesh pattern having a square arrangement.

  However, the pattern formed by the metal layer 15 is not limited to the example shown in FIG. 2 and is appropriately set according to the use of the laminated material 10. For example, the metal layer 15 may form an irregular mesh pattern, or may form a pattern other than a mesh, or may be provided with a solid shape, that is, a planar shape without a gap. It may be provided in this area.

  Furthermore, the conductive mesh 15 is partitioned into a plurality of regions by the breaking portions 15b formed between the connecting elements 15a.

  That is, the desired connecting element 15a is broken by the breaking portion 15b, the breaking portion 15b is formed between the connecting elements 15a, and the conduction between the connecting elements 15a is broken by the breaking portion 15b.

  When the width of the connecting element 15a is w and the length of the breaking portion 15b between the connecting elements 15a is L, these w and L are extremely small values as will be described later. A conductive mesh 15 can be formed.

  Such a conductive mesh 15 is made of, for example, a metal material 15A that becomes the conductive mesh 15 by using a vapor phase method (dry process) such as a vacuum deposition method, a sputtering method, an ion plating method, or a CVD method. It can be formed by depositing on the substrate 20.

  The film thickness of the conductive mesh 15 can be (numerical value) nm or more and (numerical value) nm or less.

  As the metal material that forms the conductive mesh 15, for example, one or more of gold, silver, copper, platinum, aluminum, chromium, molybdenum, nickel, titanium, palladium, indium, and alloys thereof can be used. .

<< Method for Producing Conductive Mesh Sheet >>
Next, a method for producing a conductive mesh sheet will be described with reference to FIGS. 1 (a) to 1 (e) and FIGS. 2 (a) to 2 (g).

  In this case, the patterning of the conductive mesh 15 can be performed as follows using a photolithography technique. First, as shown to Fig.2 (a), the transparent base material 20 is prepared.

  Next, a conductive metal film 15 </ b> A that becomes the conductive mesh 15 is formed on the transparent substrate 20. The metal film 15A can be formed by various methods such as a vacuum deposition method, a sputtering method, an ion plating method, and a vapor phase method (dry process) such as a CVD method. In particular, according to the vacuum deposition method, as will be described later, the metal film 15A having a thickness suitable for the case where the conductive mesh sheet 10 is used as a touch panel sensor or an electromagnetic shielding material is manufactured in a relatively short time and at a low cost. Can do. As another method, it is also effective to form the metal film 15A in a plurality of steps including sputtering and other methods, for example, sputtering and electroplating. Sputtering can form a base layer with excellent adhesion, and can increase the thickness of the metal film 15A to a desired thickness relatively quickly by subsequent electroplating.

  Thereafter, the metal film 15A on the transparent substrate 20 is patterned in a desired pattern by using a photolithography technique. Specifically, first, a resist film 30A is provided on the metal film 15A. The resist film can be formed, for example, by laminating a dry film resist.

  Next, as shown in FIG. 2B, the resist film 30A is subjected to pattern exposure in a state where the photomask 35 is disposed above the resist film 30A. Thereafter, as shown in FIG. 2C, by developing the exposed resist film 30A, a resist pattern 30 obtained by patterning the resist film 30A is obtained on the metal film 15A.

  By the way, the resist pattern 30 formed on the metal film 15A has a connection element portion 30a corresponding to the 15 connection elements 15a of the conductive mesh and a break portion 30b corresponding to the break portion 15b. In this case, in the etching process described later, the etching solution further proceeds in the horizontal direction from below the resist pattern 30 to etch the metal film 15A, so that the connection element portion 30a of the resist pattern 30 is slightly larger than the connection element 15a in plan view. It has become. The broken portion 30b of the resist pattern 30 is formed by providing a notch 30c from both sides with respect to the connecting element portion 30a, and the broken portion 30b is narrower than the connecting element portion 30a. A part of the resist film 30A remains at the broken portion 30b.

  Further, when the negative resist film 30A is used as the photomask 35 for forming the resist pattern 30 on the metal film 15A, the first opening 35A corresponding to the connection element portion 30a of the resist pattern 30 and the fracture portion 30b are formed. It consists of a mask portion 35C having a corresponding second opening 35B (see FIG. 4A).

  However, when the positive resist film 30A is used, the photomask 35 includes a mask portion 35C having a shape 35D corresponding to the connection element portion 30a of the resist pattern 30 and a shape 35E corresponding to the fracture portion 30b (FIG. 4). (See (b)).

  Next, as shown in FIGS. 2D to 2F, the metal film 15A is etched with an etchant using the patterned resist pattern 30 as a mask. Thereby, the conductive mesh 15 is formed from the metal film 15A. In this way, the conductive mesh 15 is formed in a desired pattern on the transparent substrate 20. Thereafter, the conductive mesh sheet 10 is obtained by removing the resist pattern 30 on the conductive mesh 15.

  Next, the etching process for the metal film 15A will be described in more detail with reference to FIGS. 1 (a) to (e) and FIGS. 2 (a) to (g).

  As described above, in the etching process, the etching solution further proceeds in the horizontal direction from below the resist pattern 30 to etch the metal film 15A. For this reason, the connecting element portion 30a of the resist pattern 30 is slightly larger than the connecting element 15a, and the broken portion 30b is formed by providing the notch 30c, and a part of the resist film 30A remains.

In addition, according to the present embodiment, since the conductive mesh 15 has a fine shape, the line width of the connection element 15a of the conductive mesh 15 is w, the length of the fracture portion 15b between the connection elements 15a is L, and the resist When the depth toward the inside of the notch of the broken portion 30b of the pattern 30 is a,
3μm ≦ w ≦ 30μm
1μm ≦ L ≦ 15μm
1μm ≦ a ≦ 14μm
It has become.

The values of L / w and a / w are 0.1 <L / w <1
0.05 <a / w <0.45
It has become.

  First, a resist pattern 30 having a connection element portion 30a and a fracture portion 30b is provided on the metal film 15A (FIGS. 1A and 2C).

  In this state, the metal film 15A is etched by the etching solution E using the resist pattern 30 as a mask (FIGS. 1B and 2D). At this time, the etching solution E reaches the metal film 15A exposed from the resist pattern 30, and the metal film 15A is etched.

  Next, the etching solution E further proceeds in the horizontal direction from below the resist pattern 30 to etch the metal film 15A below the resist pattern 30 (FIGS. 1C and 2E).

  Thereafter, the etching solution E reaches below the connection element portion 30a of the resist pattern 30 to etch the metal film 15A, thereby forming the connection element 15a of the conductive mesh 15. At the same time, the etching solution E reaches below the broken portion 30b, and forms the broken portion 15b of the conductive mesh 15 by etching the metal film 15A. (FIG. 1 (d) and FIG. 2 (f)).

  After forming the conductive mesh 15 in this manner, the resist pattern 30 is removed from the conductive mesh 15.

  As described above, the connection element 15a of the conductive mesh 15 is formed by the connection element portion 30a of the resist pattern 30, and the break portion 15b between the connection elements 15a is formed by the break portion 30b. When the conductive mesh 15 has a fine structure, it is necessary to form a resist pattern 30 having a fine structure corresponding to the conductive mesh 15 having this fine structure. However, the resist pattern 30 has a resolution limit at the time of exposure. Therefore, there is a limit to refinement of the shape. In particular, when the shape of the rupture portion 15b of the conductive mesh 15 is refined, it is conceivable to remove the fine portion 30e corresponding to the rupture portion 15b of the resist pattern 30 in accordance with the shape. It is practically difficult to remove the fine portion 30e corresponding to 15b due to the resolution limit when the resist pattern 30 is exposed (see FIG. 5).

  According to the present embodiment, when the break portion 15b having a fine structure among the conductive mesh 15 is formed by etching, the resist pattern 30 is removed without removing the fine portion 30e corresponding to the break portion 15b. The rupture portion 15b can be formed by etching using the rupture portion 30b formed while leaving the pattern 30 narrow. For this reason, the conductive mesh 15 having the fracture portion 15b having a fine structure can be formed with high accuracy.

DESCRIPTION OF SYMBOLS 10 Conductive mesh sheet 15 Conductive mesh 15a Connection element 15b Break part 15c Open area 15d Branch point 20 Transparent base material 30 Resist pattern 30a Connection element part 30b Break part 30c Notch 30A Resist film 35 Photomask 35A First opening 35B First Two openings 35C Mask part 35D Shape 35E Shape

Claims (7)

In a method for producing a conductive mesh sheet comprising a transparent substrate and a conductive mesh provided on the transparent substrate,
Preparing a transparent substrate;
Forming a conductive metal film on a transparent substrate;
Providing a resist pattern on the conductive metal film;
Forming a conductive mesh having a connecting element and a rupture between the connecting elements by etching the conductive metal film from above the resist pattern using an etching solution;
The resist pattern has a connection element portion corresponding to the connection element and extending in a strip shape having the same width, and a break portion provided in the connection element portion and corresponding to the break portion. The break portion corresponds to the connection element portion extending in a band shape. A method for producing a conductive mesh sheet, characterized in that a rectangular cutout is provided from both sides. When the line width of the connecting element is w and the length of the fractured portion between the connecting elements is L,
0.1 <L / w <1
The method for producing a conductive mesh sheet according to claim 1, wherein: When the line width of the connecting element is w and the depth toward the inside of each notch is a,
0.05 <a / w <0.45
The method for producing a conductive mesh according to claim 1, wherein: Photomask for producing a resist pattern used when forming a conductive mesh having a connecting element and a rupture between the connecting elements by etching the conductive metal film on the transparent substrate through the resist pattern In
The resist pattern has a connection element portion corresponding to the connection element and extending in a strip shape having the same width, and a break portion provided in the connection element portion and corresponding to the break portion. The break portion corresponds to the connection element portion extending in a band shape. Formed with rectangular cutouts from both sides,
The photomask has a mask portion in which openings corresponding to connection element portions and fracture portions of the resist pattern are formed. Photomask for producing a resist pattern used when forming a conductive mesh having a connecting element and a rupture between the connecting elements by etching the conductive metal film on the transparent substrate through the resist pattern In
The resist pattern has a connection element portion corresponding to the connection element and extending in a strip shape having the same width, and a break portion provided in the connection element portion and corresponding to the break portion. The break portion corresponds to the connection element portion extending in a band shape. Formed with rectangular cutouts from both sides,
A photomask comprising a mask portion having a shape corresponding to a connection element portion and a fracture portion of a resist pattern. When the line width of the connecting element is w and the length of the fractured portion between the connecting elements is L,
0.1 <L / w <1
The photomask according to claim 4 or 5, wherein: When the line width of the connecting element is w and the depth toward the inside of each notch is a,
0.05 <a / w <0.45
The photomask according to claim 4, wherein:

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