JP2016024847A - Method of patterning transparent conductive film, and transparent conductive laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simplified method of patterning a transparent conductive film, which can perform an etching step for patterning a transparent conductive layer without forming a resist film.SOLUTION: The patterning method, which removes a part of a transparent conductive film formed on a film substrate 1 to form a pattern, comprises the steps of: forming an amorphous transparent conductive layer 4 on the film substrate 1; crystallizing the amorphous transparent conductive layer 4 in a pattern by irradiation with a laser beam; and removing the amorphous transparent conductive layer 4 with an etchant while leaving a crystallized transparent conductive layer 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a patterning method for forming a pattern by removing a part of a transparent conductive film.

  In recent years, a touch panel is often used as an input device for a display. There are various detection methods such as a resistive film type, a capacitance type, and an optical type in the touch panel, but a capacitance type capable of multipoint detection is mainly used in smartphones and tablet terminals.

  The main basic configuration of the electrostatic capacitance type is a film in which stripe-like patterns of transparent conductive layers for longitudinal direction detection and lateral direction detection are formed and laminated.

  As a production method, a hard coat layer is formed on a film substrate such as PET by coating, and an optical adjustment layer and a transparent conductive layer are formed by sputtering. Then, in order to make handling of a film easy, a protective film is bonded together as a support material.

  FIG. 5 shows a general transparent conductive film used for a touch panel. After a transparent conductive layer is formed on a film substrate, a heat treatment step for stabilizing the characteristics by crystallizing the transparent conductive layer is performed. Done.

  The crystallized and stabilized transparent conductive film uses a resist, an etching process for forming a pattern by a photolithography method, and a metal wiring forming process that is formed on a film to connect the transparent conductive layer and the detection substrate, A touch panel is formed through a process of bonding the vertical direction detection film and the horizontal direction detection film and a process of connecting to the detection substrate.

  In general, since the protective film is handled as a support material, the protective film is often peeled before and after the step of laminating the film for detecting the vertical direction and the film for detecting the horizontal direction in the above process.

  When processing a film having a transparent conductive layer into a touch panel, the film has an annealing process, a resist coating process, a resist drying process, a resist exposure process, a resist development process, a transparent conductive layer etching process, a resist stripping process, a washing process, and a process. Wide range. Also, a mask used for resist application needs to be prepared for each pattern, and there is a problem in terms of cost.

  In many cases, the resist stripping solution and the transparent conductive layer etching solution are strong alkalis or strong acids.

Japanese Patent Laid-Open No. 10-083844

  The present invention is for solving the above-described problems, and provides a simplified method for patterning a transparent conductive film, which can perform an etching process for patterning a transparent conductive layer without forming a resist film. For the purpose.

As means for solving the above problems, the invention according to claim 1 is a patterning method for removing a part of the transparent conductive film formed on the film substrate to form a pattern,
Forming an amorphous transparent conductive layer on the film substrate;
Irradiating a laser beam to crystallize the amorphous transparent conductive layer into a pattern; and
And a step of removing the amorphous transparent conductive layer with an etching solution while leaving the crystallized transparent conductive layer.

  The invention according to claim 2 is the method for patterning a transparent conductive film according to claim 1, wherein the transparent conductive layer is made of an amorphous ITO (indium tin oxide) thin film.

  The invention according to claim 3 is the method for patterning a transparent conductive film according to claim 1 or 2, wherein the laser light is light having a wavelength of 266 nm.

  The invention according to claim 4 is the method for patterning a transparent conductive film according to any one of claims 1 to 3, wherein the thickness of the transparent conductive layer is 50 nm or less.

  The invention according to claim 5 is the transparent conductive film patterning method according to any one of claims 1 to 4, wherein diluted hydrochloric acid is used as the etching solution.

  The invention described in claim 6 is a transparent conductive laminate using the method for patterning a transparent conductive film according to any one of claims 1 to 5.

  According to the present invention, it is possible to provide a simplified method for patterning a transparent conductive film, which does not include an annealing process step for a transparent conductive layer and a step for forming a resist film.

It is a conceptual sectional view showing the composition of the amorphous transparent conductive film of the present invention. It is the conceptual cross section which showed the structure of the transparent conductive film which irradiated the laser to the amorphous transparent conductive film of this invention, and was crystallized in the pattern shape. It is a conceptual sectional view showing the state where the amorphous transparent conductive film of the present invention was crystallized in the shape of a pattern. It is a conceptual sectional view showing the state where etching processing was performed leaving the crystallized transparent conductive film. It is a conceptual sectional view showing the composition of a general transparent conductive film.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows the structure of an amorphous transparent conductive film of the present invention, and a hard coat layer 2, an optical adjustment layer 3, and an amorphous transparent conductive layer 4 are laminated on a film substrate 1 as necessary. A protective film 8 is attached to protect the amorphous transparent conductive layer 4.

  FIG. 2 shows a laser irradiation process. The amorphous transparent conductive layer 4 is irradiated with a laser beam in a pattern to obtain a crystallized transparent conductive layer 7.

  FIG. 3 shows a material having a transparent conductive layer after laser irradiation. The amorphous transparent conductive layer 4 is very weak in chemical resistance and can be easily etched with a weak alkali or weak acid solution. The crystallized transparent conductive layer 7 has excellent chemical resistance and cannot be etched with a weak alkali or weak acid. Using this etching rate difference, patterning is performed without using a resist.

  FIG. 4 shows a material having a transparent conductive layer after etching with a weak alkali or weak acid solution. By performing the etching, the crystallized transparent conductive layer 7 remains and can be patterned.

<Film base>
As the film substrate, PET, PC, and TAC can be used, and PET is suitable. A PET film having a thickness of 125 μm was used.

<Hard coat layer>
A hard coat layer was provided on a PET film substrate by a wet coating method.
The composition of the coating liquid for the hard coat layer is
Dipentaerythritol hexaacrylate (made by Nippon Kayaku Co., Ltd.) 100 parts by weight Polymerization initiator: Irgacure 907 (made by BASF) 3 parts by weight 2-methyl-1 [4- (methylthio) phenyl] -2-morpholinopropane It melt | dissolved in toluene, it was made to dry after application | coating, and the hard-coat layer with a dry film thickness of 1.2 micrometers was obtained.

<Optical adjustment layer>
Ti, Nb, and Si can be used as the optical adjustment layer, and an optical adjustment layer having a thickness of 60 μm was obtained by sputtering.

<Amorphous transparent conductive layer>
The thickness of the amorphous transparent conductive layer is desirably 50 nm or less, and an ITO thin film can be formed by a sputtering method, an electron beam method, a vapor deposition method, etc., and a sputtering method is suitable, and an ITO amorphous transparent conductive layer having a thickness of 25 nm was obtained. .

<Protective film>
A protective film protects an amorphous transparent conductive layer, peels off a protective film, and is irradiated with a laser. As the protective film, PE, PP, and PET can be used, and PE is preferable.

<Laser light>
The laser device 4 may be either a fixed type or an operating type. The wavelength range of the laser beam 5 is from the near infrared region to the ultraviolet region, and as the type of the laser device 4, an excimer laser, an Nb-YAG laser, a semiconductor laser, or the like can be used, but preferably the transparent conductive layer absorbs it. A YAG (Yttrium Aluminum Garnet) laser device capable of emitting 266 nm capable of emitting light in a large region is suitable.

A YAG laser is a device that irradiates a substance called a YAG rod that generates a laser beam with an intense flash (flash), amplifies the laser beam generated from the medium, and creates a laser beam with sufficient energy to process the material. Then, the laser beam (wavelength 1040 nm) produced by this YAG is transmitted through two harmonic crystals (SHG: Second Harmonic Generation crystal, FHG: Fourth Harmonic Generation crystal) that are wavelength conversion crystals, and the fourth harmonic (266 nm). And a pattern was drawn at a laser output of 1000 mj / cm ² .

<Weak alkali, weak acid solution>
As the etching solution for the amorphous ITO transparent conductive film, a weak alkali or weak acid solution can be used, and as the weak alkaline or weak acid solution, diluted sodium hydroxide, diluted hydrochloric acid, or the like can be used. As a pH 8 diluted sodium hydroxide solution and a weakly acidic solution, a pH 2 diluted hydrochloric acid solution is suitable.

When a diluted hydrochloric acid solution having a pH of 2 is used as an etching solution at a temperature of 23 ° C., the etching speed of the 25 nm thick amorphous ITO layer is 25 nm obtained by crystallizing 266 nm laser light with 1000 mj / cm ² energy. The etching speed is about 10 times the etching speed of the ITO layer having a thickness, and patterning is possible without using a resist, and only the laser irradiation portion can be left.

DESCRIPTION OF SYMBOLS 1 ... Film base material 2 ... Hard-coat layer 3 ... Optical adjustment layer 4 ... Amorphous transparent conductive layer 5 ... Laser apparatus 6 ... Laser beam 7 ... Crystallized transparent conductive Layer 8 ... protective film

Claims (6)

A patterning method of forming a pattern by removing a part of a transparent conductive film formed on a film substrate,
Forming an amorphous transparent conductive layer on the film substrate;
Irradiating a laser beam to crystallize the amorphous transparent conductive layer into a pattern; and
A step of leaving the crystallized transparent conductive layer and removing the amorphous transparent conductive layer with an etching solution.   The method for patterning a transparent conductive film according to claim 1, wherein the transparent conductive layer is made of an amorphous ITO (indium tin oxide) thin film.   The method for patterning a transparent conductive film according to claim 1, wherein the laser light is light having a wavelength of 266 nm.   The thickness of the said transparent conductive layer is 50 nm or less, The patterning method of the transparent conductive film as described in any one of Claims 1-3 characterized by the above-mentioned.   The method for patterning a transparent conductive film according to claim 1, wherein diluted hydrochloric acid is used as the etching solution.   The transparent conductive laminated body using the patterning method of the transparent conductive film as described in any one of Claims 1-5.

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