JP2017212250A - Method for manufacturing conductive wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a conductive wiring board including a fine and thick-film conductive wiring which has been conventionally difficult.SOLUTION: A method for manufacturing a conductive wiring board comprises the steps of: forming a first film 14 on a substrate 12 by applying an ink containing metal nanoparticles onto the substrate 12; forming a second film 14' including a burning portion 14a and a non-burning portion 14b by selectively burning a part of the first film 14; and forming a third film 14'' composed of the burning portion 14a on the substrate 12 by removing the non-burning portion 14b of the second film 14' from the second substrate 12.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a conductive wiring board.

  Conventionally, photolithography, etching, etc. are mainly used as a method for forming a conductive pattern such as a wiring and an antenna on a substrate, but there are problems in terms of the number of process steps, material use efficiency, etc. Manufacturing costs are high.

Therefore, a method of forming a conductive pattern by using a printing method such as an ink jet printing method is known (for example, see Patent Documents 1 and 2).
The inkjet printing method is a method in which ink is printed on a substrate using the inkjet method, and then dried and baked. Since ink can be selectively applied to a desired position based on the drawing data, it is possible to easily form a pattern without requiring a print that is required in the conventional printing method.
Further, as described in Patent Document 1 and Patent Document 2, it is possible to draw a fine line by the ink jet printing method, which means that a wiring having a fine width can be formed.

  As a method of forming a conductive layer using a printing method, a step of depositing a layer containing a plurality of copper nanoparticles on the surface of a substrate, and exposing at least a part of the layer to make the exposed portion conductive A method (photo-baking process) including a step of performing is proposed (see Patent Document 3).

  As the ink, a nano metal ink in which metal particles having a primary particle diameter of the order of nm are dispersed in a dispersion medium is known. Nanometal ink consists of nanoparticles, a dispersant, a solvent, etc., but since conventional dispersants are attached to particles by adsorption equilibrium to the particles, it is necessary to add a considerable amount to the solvent in order to realize the particle dispersion function There is. At this time, particularly when a polymer dispersant is used, the viscosity of the ink increases as the amount of the dispersant increases. Therefore, the concentration of the nanoparticles is increased particularly when an appropriate ink viscosity is specified as in the case of inkjet. In order to apply a predetermined amount of particles to the substrate, it must be applied multiple times. In particular, as in Patent Document 1, when using the surface energy difference between the parent ink region and the ink repellent region of the substrate, the amount of liquid ejected by one application is small. That is, there is a problem that it is difficult to form a fine and thick wiring by the ink jet printing method.

  An object of the present invention is to solve the conventional problems and to provide a method for manufacturing a conductive wiring board provided with a fine and thick conductive wiring, which has been difficult until now.

  As a result of intensive studies to solve the above problems, the present inventor applied an ink containing metal nanoparticles with a thickness larger than a predetermined line width and a thick film on the substrate, and only the fine wiring portion was applied. It has been found that the above-mentioned problems can be solved by removing an excess portion after firing.

That is, the present invention comprises a step of applying an ink containing metal nanoparticles on a substrate and forming a first film on the substrate;
Selectively firing a portion of the first film to form a second film having a fired portion and a non-fired portion;
Removing the non-fired part of the second film from the substrate, and forming a third film composed of the fired part on the substrate. I will provide a.

ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the conductive wiring board provided with the fine and thick film conductive wiring can be provided.

It is a schematic cross section for demonstrating each process in the manufacturing method of this invention.

  The first embodiment of the present invention includes a step of applying an ink containing metal nanoparticles on a substrate to form a first film on the substrate, and selectively firing a part of the first film. And forming a second film having a fired part and a non-fired part, removing the non-fired part of the second film from the substrate, and forming a third part comprising the fired part on the substrate. And a step of forming the film. A method for manufacturing a conductive wiring board.

The first embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for explaining each step in the production method of the present invention. The embodiment shown in FIG. 1 is an example in which photothermal energy is used when forming the second film and the third film.

  First, as shown in FIG. 1A, an ink containing metal nanoparticles is applied on a substrate 12 to form a first film 14 on the substrate 12. As will be described below, the ink contains metal nanoparticles and a dispersion medium, and further contains other components such as a dispersant as required. After the ink is applied on the substrate 12, the first film 14 containing metal nanoparticles is formed by volatilizing and removing the dispersion medium by heating or leaving it. Although there is no restriction | limiting in the method of apply | coating ink, It is desirable for the film thickness of the film | membrane after application | coating to become uniform. For example, an inkjet method can be mentioned. In the case of adopting the ink jet method, a method of repeatedly applying and drying several times is effective. The first film 14 is preferably formed thicker than the line width of the desired wiring pattern and thicker than the desired film thickness, and does not need to be applied exactly according to the dimensions of the wiring pattern.

  For example, the first film 14 is preferably formed to be about 2 to 6 times thicker than the line width of the desired wiring pattern. The line width of the wiring pattern and the film thickness of the first film 14 are variously determined depending on the application. The line width of the wiring pattern is, for example, 10 μm to 100 μm, preferably 20 μm to 50 μm, The film thickness of the film 14 is, for example, 1 μm to 10 μm, and preferably 2 μm to 5 μm.

Next, as shown in FIG. 1B, a part of the first film 14 is selectively baked to form a second film 14 'having a baked portion 14a and a non-fired portion 14b. The firing step is a step of firing the metal nanoparticles applied on the substrate 12. When the metal nanoparticles coated on the substrate 12 are baked, the metal nanoparticles are fused with each other, thereby eliminating the interface between the metal nanoparticles. The fired fired part 14a becomes a conductive wiring part, and the non-fired part 14b remains as it is in a coating state in which metal nanoparticles are deposited.

  The firing method is not particularly limited as long as the metal nanoparticles can be selectively fused together, and can be appropriately selected according to the purpose. Examples thereof include thermal firing, plasma firing, and light firing. It is done. In the case of heat firing and plasma firing, the atmospheric temperature during firing is preferably 100 ° C. to 200 ° C., and more preferably 100 ° C. to 150 ° C. There is no restriction | limiting in particular as a light source used at the time of the said photobaking, According to the objective, it can select suitably, For example, a xenon lamp etc. are mentioned. In addition, it is preferable to heat-dry the 1st film | membrane 14 before baking.

As a means for selectively firing, firing by light (photo-firing) is preferable. In the case of light firing, only the portion irradiated with light is fired to become a fired portion 14a, and the portion not irradiated with light becomes the non-fired portion 14b. In addition, since light has high straightness, the interface between the fired part 14a and the non-fired part 14b is clarified, so that the resolution can be increased.
In addition, only a wiring pattern portion may be irradiated with light using a mask corresponding to the pattern.

Next, as shown in FIG. 1C, the non-fired portion 14b of the second film 14 ′ is removed from the substrate 12, and the third film 14 ″ configured by the fired portion 14a on the substrate 12 is removed. Form. Examples of the method for removing the non-fired portion 14b include a method of irradiating excessive light as shown in FIG. 1C to burst the deposited particles P of the non-fired portion 14b, a wet cleaning method, and the like.
When the non-fired portion 14b is removed from the substrate 12, as shown in FIG. 1D, a fine wiring composed of the thick third film 14 ″ is completed.

  In the present invention, in order to obtain a wiring pattern having a desired line width and film thickness, the first film 14 is made thicker than the line width of the desired wiring pattern and larger than the desired film thickness as described above. It is preferable to form it thickly. By passing through each process of the present invention described above, the line width and film thickness of the first film 14 are reduced from the initial values, and a fine wiring pattern can be obtained. In the present invention, since the film thickness of the first film 14 can be set thick, a desired film thickness can be obtained even after a fine wiring pattern is completed. The extent to which the line width and film thickness of the first film 14 decrease through each step of the manufacturing method of the present invention depends on the firing temperature of the first film 14 and the non-fired portion 14b in the second film 14 ′. Depending on the removal energy, etc., these can be grasped in advance by preliminary experiments.

  The substrate and ink used in the above steps of the present invention will be described.

(substrate)
The board | substrate in embodiment of this invention is not specifically limited, such as board | substrates, such as glass and a metal, and a resin film. In particular, polyethylene terephthalate, polyethylene naphthalate, polyethersulfone, and polycarbonate are preferably used.

(ink)
The ink used in the present invention is used for forming a conductive wiring pattern, contains metal nanoparticles and a dispersion medium, and further contains other components such as a dispersant as required.

<Metal nanoparticles>
Although it will not specifically limit as a metal particle if a conductive wiring pattern can be formed, A copper particle, silver particle, nickel particle, etc. are mentioned.
The metal nanoparticles referred to in the present invention mean particles having an average primary particle size of less than 1 μm, and the particle size is preferably 2 nm to 100 nm, more preferably 5 nm to 50 nm.
In addition, the average particle diameter of a metal nanoparticle can be measured using a dynamic light scattering method, for example.
The content of the metal nanoparticles in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10 parts by mass to 50 parts by mass with respect to 100 parts by mass of the dispersion medium.

<Dispersion medium>
The dispersion medium is not particularly limited as long as the metal nanoparticles can be dispersed, and can be appropriately selected according to the purpose. Examples thereof include an organic solvent. Examples of the organic solvent include polar organic solvents such as alcohols, alkyl esters, monoalkyl glycol ethers, glycol monoalkyl ether esters or dialkyl glycol ethers, and nonpolar organic solvents such as hydrocarbons.

  The monoalkyl glycol ether is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol Ethylene glycol ethers such as monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol Monomethyl ether Pyrene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, tripropylene glycol And propylene glycol ethers such as propylene glycol monobutyl ether.

  There is no restriction | limiting in particular as said glycol monoalkyl ether ester, According to the objective, it can select suitably, For example, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate etc. are mentioned.

  The dialkyl glycol ether is not particularly limited and may be appropriately selected depending on the intended purpose. For example, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, dipropylene glycol Examples include dimethyl ether.

Examples of nonpolar organic solvents include paraffinic hydrocarbons such as pentane, hexane, heptane, octane, nonane, decane, dodecane, and tetradecane, isoparaffinic hydrocarbons such as isohexane, isooctane, and isododecane, and cycloolefin hydrocarbons such as cyclododecene, Alkyl naphthenic hydrocarbons such as liquid paraffin, aromatic hydrocarbons such as benzene, toluene, xylene, alkyl benzene and solvent naphtha, or dimethyl silicone oil, phenyl methyl silicone oil, dialkyl silicone oil, alkyl phenyl silicone oil, cyclic polydialkyl Examples thereof include silicone-based oils such as siloxane or cyclic polyalkylphenylsiloxane.

<Dispersant>
In the present invention, a dispersant is preferably added for the purpose of preventing aggregation of the metal nanoparticles in the dispersion medium. A known dispersant can be used as the dispersant, and is not particularly limited. The content of the dispersant in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 1 part by mass to 20 parts by mass with respect to 100 parts by mass of the dispersion medium.

  The disperser used when dispersing the metal nanoparticles in the dispersion medium is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a homogenizer, a ball mill, a sand mill, and an attritor.

The second embodiment of the present invention is a method for manufacturing a conductive wiring board according to the first embodiment, in which the application of the first film 14 is pattern application.
The pattern application is to selectively apply ink to only a necessary portion rather than the entire surface of the substrate 12. For example, it is assumed that wiring of an electric circuit is formed on the substrate 12. Since the application area is only a necessary part, the ink consumption is less than that of the entire surface application, which is economical.
There is no restriction | limiting in particular as said pattern application | coating method, According to the objective, it can select suitably, For example, the inkjet method, the gravure printing method, the screen printing method etc. are mentioned. Among these, the inkjet method is preferable because direct patterning can be easily performed.

The third embodiment of the present invention is a method for manufacturing a conductive wiring board according to the first or second embodiment, in which the firing of the first film 14 is performed by light irradiation.
Photo-firing means that metal nanoparticles in the ink absorb light from the light source, and the metal nanoparticles are fired by heat energy generated by generating heat. Since it is baked by light, only the wiring pattern portion can be baked particularly selectively.

In the fourth embodiment of the present invention, an exposure mask is not used when a part of the first film 14 is selectively baked by light irradiation. It is a manufacturing method of a conductive wiring board.
When using an exposure mask, it requires time and cost to produce it, and there is a problem that the manufacturing cost will be high unless it is mass-produced. By irradiating with light, these problems are solved.
As a light irradiation method that does not use an exposure mask, there is laser light irradiation. Although it does not specifically limit as a wavelength of a laser beam, It is preferable that it is a wavelength which an ink material, especially a metal nanoparticle can absorb.

In the fifth embodiment of the present invention, the conductive wiring in the first to fourth embodiments is characterized in that the method of removing the non-fired portion 14b of the second film 14 'is light irradiation. A method for manufacturing a substrate.
When excessive light is irradiated, organic substances such as a dispersant in the ink are instantly decomposed and gasified due to excessive heat generation, and burst, and non-fired metal nanoparticles are scattered. Examples of the light irradiation method include a method of selectively overexposing the non-fired portion 14b with a laser, and a method of overexposing the entire surface with a flash lamp as described later. When the entire surface is excessively irradiated, since the fired portion 14a that has already been fired is in a state where the base material 12 and the metal layer made of metal nanoparticles are in close contact with each other, it is not affected by the excessive irradiation and remains as it is. .

The sixth embodiment of the present invention is characterized in that the removed scattered matter is sucked or blown off at the time of removing the non-fired portion 14b of the second film 14 '. It is a manufacturing method of a conductive wiring board.
When the non-fired portion 14b of the second film 14 ′ is removed, the non-fired ink material is scattered, and a part of the ink material may adhere to the substrate 12. This becomes a foreign matter to the electric circuit, which may cause a short circuit. Since the non-baked ink material flying according to the present embodiment does not adhere to the substrate 12, the reliability of the electric circuit is improved.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the following examples. In addition, a part means a mass part.

Example 1
(Preparation of ink)
An ink of Example 1 of Japanese Patent Application Laid-Open No. 2014-177600 was prepared.
That is, 5 parts of the following dispersant 1, 40 parts of copper particles QSI-Nano Copper Powder (manufactured by QuantumSphere) and 100 parts of ethylene glycol monomethyl ether were ultrasonically dispersed for 10 minutes, and then a high-speed mixer fill mix (manufactured by Primex) ) For 10 minutes. Next, coarse particles were removed using a filter having a pore size of 1 μm to obtain an ink containing metal nanoparticles made of copper having an average primary particle size of 75 nm.
Dispersant 1: Into a reaction vessel equipped with a stirrer, a thermometer, and a reflux condenser, 300 parts of ethanol was added and heated to 60 ° C. under a nitrogen purge. Next, a liquid mixture consisting of 90 parts of polyethylene glycol methyl ether methacrylate having a number average molecular weight of 500, 10 parts of methacrylic acid and 1 part of a polymerization initiator azobisdimethylvaleronitrile was added dropwise over 1 hour, followed by stirring at 60 ° C. for 5 hours. did. Further, ethanol was evaporated using an evaporator to obtain Dispersant 1.

(Ink application to the substrate)
Using the above ink, a pattern was drawn on a PET film with a receiving layer (Graphic Arts transparent film, manufactured by Pictorico Co., Ltd.) using an ink jet apparatus (PJ, Inc., IJ-DESK). After drawing, it was oven dried at 60 ° C. for 30 minutes. This coating and drying was repeated 4 times to prepare a first film on the substrate. The line width of the first film was 120 μm and the film thickness was 5.8 μm.

(Selective firing of wiring part)
When an infrared laser with a wavelength of 810 nm is irradiated with light at an output of 300 mW, a beam diameter of 30 μm, and a sweep speed of 1 mm / s in accordance with the center line of the first film, only the irradiated portion is fired, and a second comprising a fired portion and a non-fired portion. The film was made.

(Removal of non-fired part)
When a xenon flash lamp firing device (SINTERON 2000, manufactured by XENON) was used to irradiate light with an energy of pulse width 2 ms and 20 J / cm ² , particles in the other non-fired portions were scattered on the substrate without changing the fired portions. Disappeared from. By this process, a third film was formed on the substrate. The third film had a line width of 28 μm and a film thickness of 2.8 μm.

Example 2
In the selective firing of the wiring portion of Example 1, the wiring is irradiated with light having a pulse width of 2 ms and energy of 16 J / cm ² from a xenon flash lamp firing device through a photomask that transmits light only in the wiring portion (width 30 μm). When the same procedure as in Example 1 was performed except that the portion was photobaked, the line width of the third film was 30 μm and the film thickness was 2.8 μm.

Example 3
The ink coating on the substrate of Example 1 was performed in the same manner as in Example 1 except that the entire surface of the substrate was coated with a wire bar (wet gap 40 μm) instead of inkjet, and the line width of the third film was 27 μm. The thickness was 3.4 μm.

12 Substrate 14 First film 14 ′ Second film 14 ″ Third film 14a Firing part 14b Non-firing part P Deposited particles

JP 2013-16773 A JP 2013-214649 A Special table 2010-528428 gazette

Claims (6)

Applying an ink containing metal nanoparticles on a substrate and forming a first film on the substrate;
Selectively firing a portion of the first film to form a second film having a fired portion and a non-fired portion;
Removing the non-fired part of the second film from the substrate, and forming a third film composed of the fired part on the substrate. .   The method for manufacturing a conductive wiring board according to claim 1, wherein the application of the first film is a pattern application.   The method for manufacturing a conductive wiring board according to claim 1, wherein the baking of the first film is performed by light irradiation.   The method for manufacturing a conductive wiring board according to claim 3, wherein an exposure mask is not used when part of the first film is selectively baked by light irradiation.   The method for producing a conductive wiring board according to claim 1, wherein the method for removing the non-fired portion of the second film is light irradiation. The method for manufacturing a conductive wiring board according to claim 1, wherein the removed scattered matter is sucked or blown off at the time of removing the non-fired portion of the second film.