KR102084575B1 - Ink composition for flash light sintering and method for manufacturing substrate using the same - Google Patents

Abstract

The present invention relates to an ink composition for light sintering and a method for manufacturing a wiring board using the same. The present invention relates to an ink composition capable of smoothly sintering light even at low light irradiation energy and forming a wiring pattern having good density and electrical conductivity. It is to provide. The present invention provides an ink composition for light sintering comprising silver oxide, a copper oxide nanoparticle having a copper oxide film on the outside, a reducing agent, a dispersant, a binder, and a solvent for reducing the nanocopper oxide particles to nanocopper particles upon light irradiation. In another aspect, the present invention provides a screen printing step of forming a preliminary wiring pattern by screen printing the ink composition for optical sintering on a flexible substrate body, a drying step of drying the screen printed preliminary wiring pattern, and irradiating light to the dried preliminary wiring pattern. By reducing and sintering the oxidized copper of the nano-copper oxide particles included in the preliminary wiring pattern to provide a method of manufacturing a wiring board comprising an optical sintering step of forming a wiring pattern on the substrate body.

Description

Ink composition for optical sintering and manufacturing method of wiring board using same {Ink composition for flash light sintering and method for manufacturing substrate using the same}

The present invention relates to an ink composition and a method of manufacturing a wiring board using the same, and more particularly, to an ink composition for optical sintering comprising a silver oxide and nano copper particles having a copper oxide film formed on the outside thereof, and a method of manufacturing a wiring board using the same. will be.

Presently used in printed electronic technology, conductive inks are mainly used for the manufacture of wiring patterns of wiring boards such as display panels, solar panels, digitizers, printed circuit boards, and the like.

As such conductive ink, silver ink containing silver (Ag) and silver paste are mainly used. The conductive ink containing silver may include metal particles such as gold, platinum, and palladium in addition to silver.

However, although silver ink or silver paste is formed as a wiring pattern on the wiring board through a thermal sintering process, since the price of silver contained in the conductive ink is very expensive, when the wiring pattern is formed using the conductive ink, There is a limit to lower manufacturing costs. In addition, the heat sintering process is required, and there are many limitations in the selection of the wiring board or the ink.

In addition, the wiring pattern formed by using silver ink or silver paste has a problem of peeling and adhesion, and has a high resistance value of the wiring pattern formed after thermal sintering.

Korea Patent Registration No. 10-1276237 (2013.06.12.)

In order to solve this problem, a technique for implementing a wiring pattern using an inexpensive conductive ink by including copper particles instead of silver particles in the conductive ink is being developed.

Pure nanocopper particles, however, are cheaper than silver particles, but are more expensive because of lower synthetic yields.

In addition, when the wiring pattern is formed of the conductive ink containing copper particles, since the copper oxide film is easily formed on the surface of each copper particle included in the conductive ink, the electrical resistance of the wiring pattern becomes very high, and thus the wiring pattern cannot function. Problems may arise.

For this reason, in order to prevent a copper oxide film from forming on the surface of each copper particle, it is necessary to bake for 1 hour to 3 hours at a high temperature of 300 ° C. or higher under an inert gas atmosphere. However, when baking for a long time at a high temperature in an inert gas atmosphere, rather than the conductive ink using the silver particles may cause a problem that the production cost is further increased.

In addition, when the wiring board is exposed to a high temperature of 300 ° C. or more, a problem may occur that the wiring board itself is damaged. In particular, since a thin flexible wiring board such as a flexible printed circuit board (FPCB) is vulnerable to high temperature, there is a problem in that a conductive ink containing copper particles cannot be used for manufacturing a flexible printed circuit board.

Accordingly, an object of the present invention is to reduce the manufacturing process time and manufacturing cost of the wiring board, and to provide an ink composition for optical sintering which can suppress the damage of the wiring board by a sintering process through short light irradiation and a method of manufacturing the wiring board using the same There is.

Another object of the present invention is to provide an ink composition for optical sintering which can form a wiring pattern without damaging a thin flexible wiring board such as a flexible printed circuit board, and a method of manufacturing a wiring board using the same.

Another object of the present invention is to provide an ink composition for optical sintering which can improve the density and optical sintering efficiency of a wiring pattern, and a method of manufacturing a wiring board using the same.

In order to achieve the above object, the present invention provides a silver oxide, nano copper oxide particles having a copper oxide film on the outside, for light sintering comprising a reducing agent, a dispersant, a binder and a solvent for reducing the nano copper oxide particles to nano copper particles in light irradiation It provides an ink composition.

In the ink composition for optical sintering according to the present invention, the composition ratio of the silver oxide and the nano copper oxide particles may be 0.1: 9.9 to 4: 6.

In the ink composition for optical sintering according to the present invention, silver oxide and nano copper oxide particles excluding the solvent may be 70 to 94% by weight.

In the ink composition for optical sintering according to the present invention, the silver oxide powder may have a size of 2 μm or less, and the nano copper oxide particles may have a D ₅₀ of 900 nm or less and a Dmax of 2 μm or less.

In the ink composition for optical sintering according to the present invention, the reducing agent may include an aldehyde compound, an acid containing ascorbic acid, a phosphorus compound, a metal reducing agent, p-benzoquinone, hydroquinone or anthraquinone.

The dispersant may include a cationic dispersant, an anionic dispersant or a zwitterionic dispersant.

The binder is PVP, PVA and PVC, cellulose resin, polyvinyl chloride resin, copolymer resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, acrylic resin, vinyl acetate-acrylic acid ester copolymer resin, butyral resin, alkyd Resins, epoxy resins, phenol resins, rosin ester resins, polyester resins or silicones.

The solvent is ethylene glycol (EG), diethylene glycol (DEG), dibasic ester (DBE), carbitol acetate (CA), dipropylene glycol methyl ether (Dipropylene glycol methyl ether; DPM or DPGME), butyl carbitol acetate (BCA), butyl carbitol (BC), texanol, terpineol or butyl acrylate; BA).

The present invention also provides a silver oxide on the flexible substrate body, nano copper oxide having a copper oxide film on the outside, for light sintering comprising a reducing agent, a dispersant, a binder and a solvent for reducing the nano copper oxide particles to nanocopper particles upon light irradiation A screen printing step of screen printing the ink composition to form a preliminary wiring pattern; A drying step of drying the screen printed preliminary wiring pattern; And an optical sintering step of irradiating light on the dried preliminary wiring pattern to reduce and sinter the oxidized copper of the nanocopper oxide particles included in the preliminary wiring pattern to form a wiring pattern on the substrate body. It provides a method for producing a wiring board using an ink composition for optical sintering comprising a.

According to the present invention, a wiring pattern of a wiring board is formed by forming a wiring pattern of a wiring board using nano copper particles (hereinafter referred to as 'nanocopper oxide particles') having silver oxide and a copper oxide film formed on the outer side of the ink composition for optical sintering. The manufacturing cost can be reduced. That is, since the wiring pattern of the wiring board can be formed by using an ink composition containing silver oxide and nano copper oxide particles which are less expensive than the silver material, the manufacturing cost of the wiring board can be reduced.

In addition, when the ink composition containing silver oxide and nano copper oxide particles is printed on the wiring board, the copper oxide film formed on the surface of the nano copper particles may be removed through a light sintering process through short light irradiation instead of thermal sintering. Therefore, damage to the wiring board can be suppressed by reducing the process time and by the light sintering process through short light irradiation. At this time, the nano copper oxide particles are insulated before photo sintering, but are reduced to pure nanoparticles through photo sintering, thereby forming a wiring pattern of a copper material having electrical conductivity.

Therefore, the wiring pattern may be formed on the substrate body of the flexible printed circuit board used for the digitizer without damaging the substrate body by using the ink composition according to the present invention.

Since the ink composition for optical sintering which concerns on this invention contains silver oxide, compared with using nano copper oxide particle | grains independently, the density of a wiring pattern can be improved. That is, the wiring pattern is formed in a form containing a plurality of pores therein due to the gas generated during the light sintering process of the ink composition containing only copper nanoparticles as copper particles. On the other hand, when the silver oxide is included as in the present invention, since the amount of gas generated in the light sintering process can be reduced to reduce the amount of pores that may exist inside the wiring pattern, the wiring pattern with improved density can be formed. have.

Since the ink composition for optical sintering which concerns on this invention contains silver oxide, compared with using nano copper oxide particle | grains independently, an optical sintering efficiency can be improved. That is, since silver oxide contained in the ink composition has a brown or black color, the light absorption rate is high when the light is irradiated and decomposed to facilitate sintering, thereby improving the light sintering efficiency. This has the advantage that the light sintering can be performed smoothly even at low light irradiation energy.

In addition, when the wiring pattern is formed on the wiring board by using an ink composition including silver oxide and nano copper oxide particles, the wiring pattern may be formed to have a high aspect ratio by a screen printing method. That is, since the signal transmission speed of the wiring board depends on the resistance, it can be formed by the screen printing method so that the wiring pattern has a high aspect ratio.

1 is a SEM and HRTEM photograph showing the nano-copper oxide particles contained in the ink composition for optical sintering according to the present invention.
2 is a block diagram schematically illustrating an apparatus for manufacturing a wiring board using the ink composition for optical sintering according to an embodiment of the present invention.
3 is a flowchart illustrating a method of manufacturing a wiring board using the ink composition for optical sintering according to the embodiment of the present invention.
4 to 7 are views showing each step according to the manufacturing method of FIG.
4 is a cross-sectional view showing a wiring board;
5 is a cross-sectional view illustrating a step of forming a preliminary wiring pattern by screen printing an ink composition for optical sintering on a wiring board;
6 is a cross-sectional view showing a step of drying the screen printed preliminary wiring pattern;
7 is a cross-sectional view illustrating a step of forming a preliminary wiring pattern as a wiring pattern through light sintering.
8 is a photograph showing a preliminary wiring pattern before light sintering.
9 is a photograph showing a wiring pattern after light sintering.

In the following description, only parts necessary for understanding the embodiments of the present invention will be described, it should be noted that the description of other parts will be omitted in the scope that does not distract from the gist of the present invention.

The terms or words used in the specification and claims described below should not be construed as being limited to the common or dictionary meanings, and the inventors are appropriate to the concept of terms in order to explain their invention in the best way. It should be interpreted as meanings and concepts in accordance with the technical spirit of the present invention based on the principle that it can be defined. Therefore, the embodiments described in the present specification and the configuration shown in the drawings are only preferred embodiments of the present invention, and do not represent all of the technical idea of the present invention, and various equivalents may be substituted for them at the time of the present application. It should be understood that there may be variations and variations.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

The ink composition for optical sintering according to the present invention comprises nano copper oxide particles having a silver oxide and a copper oxide film, and further includes a reducing agent, a dispersant, a binder, and a solvent for reducing copper oxidized by light irradiation to form nano copper particles. can do.

Silver oxide is silver oxide (I) or silver oxide (II). Here, silver oxide (I) is Ag ₂ O, which is a dark brown to dark brown material having a specific gravity of 7.22, and is decomposable at around 160 ° C. Silver oxide (II) is AgO, a material of gray black specific gravity of 7.483, which is decomposable at around 100 ° C.

Such silver oxide will be described later in the description of the light sintering process, but when irradiated with xenon white light, light is easily absorbed due to brown or black color, is easily decomposed to sinter, and a more precise wiring pattern can be made. .

Nano-copper oxide nanoparticles are insulators, but are converted into pure nano-copper particles having conductive conductivity by light irradiation and used as a source of a conductor. Nano copper oxide particles are core-shell (core-shell) type of particles, the copper oxide film on the surface may be particles having a thickness of 50nm or less. In this case, the reason why the copper oxide film uses nano copper oxide particles having a thickness of 50 nm or less may be a problem that some of the copper oxide film is not reduced to copper by light irradiation when the thickness of the copper oxide film exceeds 50 nm. Because. The nano copper oxide particles may have a particle size of D ₅₀ of 900 nm or less and D max of 2 μm or less. For example, FIG. 1 is a SEM and HRTEM photograph showing nano copper oxide particles having a D ₅₀ of 70 nm. (A) is a SEM photograph, (b) is an HRTEM photograph.

The particle size of the nano-copper oxide needs to be selectively controlled according to the application. For example, when manufacturing a metal mesh, which is a substitute for ITO transparent electrodes for touch screens, line widths within 1 μm are required to solve visibility problems such as moiré and starburst. In this case, the particle size is controlled to 300 nm or less. It is desirable to.

On the other hand, the digitizer double-sided FPCB, which requires a line width of 75 μm or less, does not necessarily need to be 300 nm or less, and the maximum particles may be used in the range where light sintering is possible.

The composition ratio of silver oxide and nano copper oxide particles may be 0.1: 9.9 to 4: 6. In the composition ratio of silver oxide and nano copper oxide particles, when the ratio of silver oxide is less than 0.1, there is little improvement in the compactness of the wiring pattern by silver oxide, and only a cost increase is caused. On the contrary, when the ratio of silver oxide exceeds 4, there is a problem in that a porous wiring pattern is generated due to excessive oxygen emission.

The reducing agent is irradiated with light to reduce the copper oxide film of the nanocopper oxide particles to copper. That is, the reducing agent converts the nanocopper oxide particles into pure nanocopper particles. As such a reducing agent, an aldehyde compound, an acid containing ascorbic acid, a phosphorus compound, a metal reducing agent, p-benzoquinone, hydroquinone or anthraquinone can be used.

For example, formaldehyde, acetaldehyde, etc. may be used as the aldehyde-based compound used as a reducing agent.

Acids used as reducing agents include oxalic acid, formic acid, ascorbic acid, sulfonic acid, dodecyl benzene sulfonic acid, and maleic acid. , Hexamic acid, phosphoric acid, O-phthalic acid, acrylic acid, etc. may be used.

Phosphites, hypophosphites and phosphorous acid may be used as phosphorus compounds used as reducing agents. The phosphorus-based compound in the reducing agent is described in more detail, for example, hydrogen phosphonates (acid phosphites) containing HP (O) ₂ OH ^- groups, such as NH ₄ HP (O) ₂ OH containing PO ^{3 3-} groups, H ₂ P ₂ O ₅ ^2- Diphosphites comprising, phosphites comprising HPO ₃ ^2- , such as (NH ₄ ) ₂ HPO ₃ OH ₂ O, CuHPO ₃ OH ₂ O, SnHPO ₃ , and Al ₂ (HPO ₃ ) ₃ ㅇ 4H ₂ O, etc. (RO) phosphite ester, Hypophosphite ( H 2 PO 2 -) , such as _{3 P, phosphatidylcholine, triphenylphosphate, cyclophosphamide} , parathion, Sarin (phosphinate), Glyphosate (phosphonate), fosfomycin (phosphonate), zoledronic acid (phosphonate), and Glufosinate Organophosphorus such as (phosphinate), organic phosphines (PR ₃ ) such as triphenylphosphine, Phosphine oxide (OPR ₃ ) such as Triphenylphosphine oxide, Phosphonite (P (OR) R ₂ ) such as (CH ₃ O) ₂ PPh, Phosphonite (P (OR) ₂ R), Phosphinate (OP (OR) R ₂ ), organic phosphonates (OP (OR) ₂ R), Phosphate (PO ₄ ^3- ), parathion, malathion, methyl parathion, chlorpyrifos phosphorus compounds containing unsaturated groups such as organophosphate (OP (OR) ₃ ), such as diazinon, dichlorvos, phosmet, fenitrothion, tetrachlorvinphos, azamethiphos, and azinphos methyl.

As the metal-based reducing agent, lithium aluminum hydride (LiAlH ₄ ), diisobutylaluminum hydride (DIBAL-H), and Lindlar catalyst may be used.

By including the reducing agent as a catalyst of the ink composition for light sintering, sintering through light irradiation can be performed to suppress damages such as warpage or shrinkage of the wiring board, and can be compared with laser etching and thermal sintering. You can save time and reduce process costs.

In the ink composition for optical sintering according to the present invention, the reducing agent is preferably added in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the nano copper oxide particles. When the amount of the reducing agent added is more than 5 parts by weight, a problem of lowering homogeneity may occur due to lowering dispersibility and lowering compatibility in the ink composition for optical sintering. On the contrary, when the amount of the reducing agent is less than 0.1 part by weight, a problem may occur in which the reduction and sintering of the nano-copper oxide is not performed smoothly by monochromatic light irradiation.

The dispersant uniformly disperses the nano copper oxide particles in the ink composition for optical sintering, thereby suppressing the generation of pores in the wiring pattern formed by the optical sintering. As such dispersants, cationic dispersants, anionic dispersants or zwitterionic dispersants may be used.

Examples of the dispersant include amine polymer dispersants such as polyethylene imine and polyvinylpyrrolidone, and hydrocarbon-based polymer dispersants having a carboxylic acid group in molecules such as polyacrylic acid and carboxymethyl cellulose, foam (polyvinyl alcohol) and styrene-maleic acid. Polymeric dispersants having a polar group such as a copolymer, an olefin-maleic acid copolymer, or a copolymer having a polyethylene imine portion and a polyethylene oxide portion in one molecule may be used, but are not limited thereto.

The binder serves as a material that binds the nano copper oxide particles when the wiring pattern is formed using the ink composition for optical sintering, and serves to maintain the excellent printability and high aspect ratio of the wiring pattern.

Such binders include PVP, PVA and PVC, cellulose resins, polyvinyl chloride resins, copolymer resins, polyvinyl alcohol resins, polyvinylpyrrolidone resins, acrylic resins, vinyl acetate-acrylic acid ester copolymer resins, butyral resins, Alkyd resins, epoxy resins, phenol resins, rosin ester resins, polyester resins or silicones can be used, but are not limited thereto.

For example, a mixed resin of epoxy acrylate, polyvinyl acetal, and phenol resin may be used as the binder. By using the above-mentioned mixed resin as a binder, heat curing at a temperature of about 150 ° C. (a three-dimensional network structure can be formed to form a thermally very stable structure) can improve the heat resistance of the ink composition for optical sintering. Can be.

In addition, the ink composition for optical sintering according to the present invention has a heat resistance of 280 ℃ or more can be soldered (soldering), it is possible to be electrically connected by soldering, such as passive devices, active devices and other circuit wiring by soldering possible There is this. If the heat resistance of the ink composition is not satisfied, it may cause defects due to increased resistance and lowered mechanical properties at the contact point or junction. Rising resistance can cause delays in signal transmission or various problems on the entire device.

Moreover, it is preferable that the mixing ratio of the epoxy acrylate, polyvinyl acetal, and a phenol resin contained in a binder is 1: 0.1-1: 0.1-5.

It is preferable that the addition amount of a binder with respect to 100 weight part of nano copper oxide particles is 3-10 weight part. If the content of the binder exceeds 10 parts by weight, there is a problem of causing an increase in the resistance component between the particles to increase the resistance, and if less than 3 parts by weight, it is difficult to cover all of the surface of the particles, it is rheologically unstable, It is not preferable because there is a problem that the adhesive strength with the wiring board is lowered.

The solvent may be a hydrocarbon solvent, a chlorinated hydrocarbon solvent, a cyclic ether solvent, a ketone solvent, an alcohol, a polyhydric alcohol solvent, an acetate solvent, an ether solvent of a polyhydric alcohol, or a terpene solvent. It is not limited to this. For example, the solvent may be ethylene glycol (EG), diethylene glycol (DEG), dibasic ester (DBE), carbitol acetate (CA), dipropylene glycol methyl ether (Dipropylene glycol). methyl ether; DPM or DPGME), butyl carbitol acetate (BCA), butyl carbitol (BC), texanol, terpineol or butyl acrylate; BA).

In the ink composition for optical sintering according to the present invention, the metallic particles including the nano-copper oxide particles in the solid content excluding the solvent are preferably 70 to 94% by weight. The reason is that, if it is less than 70% by weight, the current heat by light irradiation is hardly transmitted to all the particles, thereby making it difficult to manufacture a dense wiring pattern. On the contrary, if the content exceeds 94% by weight, the content of the metallic particles is excessive and the viscosity is not appropriate to form the wiring pattern, and the content of the reducing agent is insufficient compared to the content of the particles, so that excessive light energy is required to sinter the light. to be. If excessive light energy is irradiated on the wiring board, a problem may occur that the wiring board is damaged.

Meanwhile, in the ink composition for optical sintering according to the present invention, an amine-based antioxidant, a thixotropic agent, a leveling agent, or a silane coupling agent for enhancing adhesion may be selectively added depending on the use environment.

Such an ink composition for optical sintering according to the present invention is a synthetic resin substrate selected from polyimide, polyurethane, PMMA and PET, a metal substrate selected from stainless steel, aluminum, gold and silver or ITO (Indium Tin Oxide) and ceramic, glass And it can be used for both a non-metal substrate selected from silicon, etc., it is possible to improve the adhesion of the wiring pattern to them, to improve the printability of the wiring pattern and to implement a high aspect ratio (high aspect ratio). In particular, the ink composition for optical sintering according to the present invention may be used for the manufacture of a wiring pattern of a flexible wiring board having a thin thickness and susceptibility to heat.

The screen printing method may be used as a printing method for forming a wiring pattern using the ink composition for optical sintering according to the present invention, but gravure, offset, flexo, aerosol jet, slit die coating, bar coating, etc. are possible. . The ink composition for optical sintering according to the present invention can be used by applying to various printing methods through a change in viscosity or solvent.

The apparatus for manufacturing a wiring board using the ink composition for optical sintering according to the present invention will be described with reference to FIG. 2 as follows. 2 is a block diagram schematically illustrating an apparatus for manufacturing a wiring board using the ink composition for optical sintering according to an embodiment of the present invention.

Referring to FIG. 2, the apparatus 100 for manufacturing a wiring board according to the present embodiment includes a wiring board supply unit 10, a screen printing unit 20, a printing inspection unit 30, a drying unit 40, and an optical sintering unit ( 50) and a wiring board recovery part 60. In this case, the wiring board supply unit 10, the screen printing unit 20, the printing inspection unit 30, the drying unit 40, the optical sintering unit 50, and the wiring board recovery unit 60 are arranged in a line with the wiring board supply unit 10. From the wiring board recovery unit 60 may be sequentially installed.

The wiring board supply unit 10 supplies a substrate body to be used for manufacturing the wiring board. In this case, a wiring pattern may not be formed on both surfaces of the substrate body, or a wiring pattern may be formed on one surface of the substrate body.

In this case, the substrate body may be made of a plastic material having insulation and flexibility used in manufacturing a flexible printed circuit board. For example, the substrate body may be made of polyimide, polyethersulphone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethyelenen napthalate (PEN), Polyethylene terephthalate (polyethyeleneterepthalate (PET), polyphenylene sulfide (PPS), polyallylate, polycarbonate (PC), cellulose triacetate (CTA) or cellulose acetate propionate (cellulose) acetate propinonate (CAP) may be used, but is not limited thereto.

The wiring board recovery part 60 is installed on the opposite side of the wiring board supply part 10 and recovers the board body on which the wiring pattern manufacturing process is completed.

In this case, when the wiring board is a flexible printed circuit board, the wiring board supply unit 10 may provide the board body in a roll to roll manner or in the form of a unit sheet attached to the carrier frame. In the roll-to-roll method, the substrate body provided by the supply roll of the wiring board supply unit 10 in which the substrate body is wound has a screen printing unit 20, a printing inspection unit 30, a drying unit 40, and an optical sintering unit 50. After passing through it can be recovered by winding the recovery roll of the drain board recovery unit 60.

The screen printing unit 20 is a screen printing part of the preliminary wiring pattern to be formed as a wiring pattern on the substrate body supplied from the wiring board supply unit 10. As shown in FIG. 5, the screen printing unit 20 fills the pattern hole 23 with the screen 21 on which the pattern holes 23 are formed to correspond to the wiring pattern, and the ink composition 27 for optical sintering. It may be configured to include a squeeze 25. Although not shown, the screen printing unit 20 includes a stage for supporting the substrate body 71 and performing screen printing.

Screen printing in the screen printing unit 20 may be performed as follows. When the substrate body 71 is transferred onto the stage, in a state in which the screen 21 is mounted on the substrate body 71, the ink composition 27 for optical sintering supplied onto the screen 21 is pushed with a squeeze 25 to form a pattern. The ink composition 27 for light sintering is filled into the hole 23. By separating the screen 21 from the substrate body 71, the preliminary wiring pattern 73 may be formed on the substrate body 21. For example, the preliminary wiring pattern 73 may be formed by screen printing on the substrate body 71 with a line width of 30 to 300 μm and a thickness of 5 to 20 μm.

Here, the preliminary wiring pattern refers to a screen printed wiring pattern before light sintering, and is formed into a wiring pattern by light sintering.

The printing inspection unit 30 is installed adjacent to the screen printing unit 20 and inspects a preliminary wiring pattern printed on the substrate body discharged from the screen printing unit 20. That is, the printing inspecting unit 30 checks whether the printed state of the preliminary wiring pattern on the substrate body is properly printed using the camera. If there is no abnormality as a result of the inspection, the substrate body may be transferred to the drying unit 40, but if there is an abnormality, an alarm message may be output or the driving of the manufacturing apparatus 100 of the wiring board may be temporarily stopped. The alarm message can be notified to the worker through an alarm sound, an alarm light, or the like.

The drying unit 40 is installed adjacent to the printing inspection unit 30, and removes the solvent included in the preliminary wiring pattern formed on the substrate body on which the printing inspection process is completed. For example, the drying unit 40 may provide hot air or infrared rays of 60 to 100 ° C. to the preliminary wiring pattern to dry and remove the solvent included in the preliminary wiring pattern.

The optical sintering unit 50 is installed adjacent to the drying unit 40, and irradiates light on the dried preliminary wiring pattern to reduce and sinter the oxidized copper of the nanocopper oxide particles included in the preliminary wiring pattern on the substrate body. A wiring pattern is formed.

At this time, the optical sintering unit 50 may be formed as a wiring pattern by reducing and sintering the preliminary wiring pattern by irradiating monochromatic pulsed light onto the preliminary wiring pattern. Monochromatic pulsed light may use white light generated from a xenon flash lamp, and pulsed light or other colored light generated from other types of lamps may be used.

In the present invention, the light sintering means a series of processes in which metal particles are metallized after forming a necking by irradiating pulsed xenon white light to a preliminary wiring pattern. This optical sintering is caused by two sintering mechanisms. One is sintering as metal particles absorb light and the Joule heat generated at that time is propagated to other particles. The other is that the metal particles are melted by the heat of pure xenon white light and sintering proceeds. However, in the latter case, due to the inherent characteristics of the metal, most of the light is reflected, which is not easy to cause sintering and damages the substrate, or requires excessive light irradiation energy to shorten the lamp life.

The reason for using the white light generated from the xenon flash lamp as the monochromatic pulsed light in this embodiment is that the pulse width, pulse gap, pulse numbers and intensity can be precisely adjusted. It is easy to adjust.

Monochromatic pulsed light used in the manufacture of flexible printed circuit boards includes pulse widths of 100 to 5000 microns, pulse gaps of 0.01 ms to 1 ms, output voltages of 100 to 500 V, number of pulses 1 to 10, and intensity of 3 J / cm 2 to 60 White light of J / cm 2 can be used. For example, when the thickness of the preliminary wiring pattern is less than 9 μm, the pulse number of the monochromatic pulsed light may be 1, and when the thickness is 9 μm or more, the pulse number of the monochromatic pulsed light may be 2 or more.

In this case, when the pulse width of the white light is greater than 5000 kHz, the incident energy per unit time is reduced, thereby reducing the optical sintering efficiency.

When the pulse gap is greater than 1 ms or the number of pulses is greater than 10 times, the ink composition for photo sintering may not be properly sintered due to the low energy of white light.

In addition, when the pulse gap is less than 0.01ms or the intensity of the white light is more than 60 J / ㎠ may damage the lamp or shorten the life of the lamp, it may damage the flexible printed circuit board.

In addition, when the intensity of the white light is 3 J / ㎠ or less, the reduction reaction for reducing the copper oxide film of the nano-copper oxide particles to copper is weak, thereby reducing the electrical resistance characteristics of the wiring pattern.

On the contrary, when the intensity of the white light is 60 J / cm 2 or more, high energy is provided to the flexible printed circuit board, which may cause damage such as shrinkage, warpage and distortion of the substrate body, and separation of the wiring pattern from the substrate body. Can be.

As described above, the ink composition for optical sintering according to the present invention includes silver oxide and nano copper oxide particles, thereby forming a more compact and superior wiring pattern. In addition, the ink composition for light sintering according to the present invention because the light sintering proceeds smoothly even at low light irradiation energy, it is possible to lower the manufacturing cost of the wiring board.

The wiring board on which the wiring pattern is formed by light sintering is recovered to the wiring board collecting part 60.

The wiring pattern (hereinafter, referred to as an “upper wiring pattern”) may be formed on the upper surface of the substrate body through the apparatus 100 for manufacturing a wiring board according to the present embodiment, but is not limited thereto. The lower wiring pattern may also be formed on the lower surface of the substrate body by providing the recovered substrate body to the wiring board recovery unit 60 in the second wiring board manufacturing apparatus capable of forming the lower wiring pattern on the lower surface of the substrate body. have. In this case, the manufacturing apparatus of the second wiring board may have the same structure as the manufacturing apparatus 100 of the wiring board according to the present embodiment. For example, the manufacturing apparatus of the first wiring board and the manufacturing apparatus of the second wiring board forming the lower wiring pattern may be connected inline to form the upper wiring pattern and the lower wiring pattern of the substrate body.

Alternatively, the substrate body having the upper wiring pattern formed on the upper surface by light sintering may be faced upward through rewinding or tilting, and then screen printing, drying, and optical sintering may be performed on the lower surface of the substrate body. It is also possible to form a lower wiring pattern through. That is, a double-sided wiring board having upper and lower wiring patterns formed on both sides of the substrate body may be manufactured.

For example, an apparatus for manufacturing a double-sided wiring board which tilts a wiring board to manufacture an upper surface wiring board includes a wiring board supply unit, a first screen printing unit, a first printing inspection unit, a first drying unit, and a first optical sintering unit for forming an upper wiring pattern. A tilting part for tilting the upper wiring pattern manufacturing part and a substrate body passing through the first optical sintering part so that the lower surface of the substrate body faces upward, a second screen printing part connected to the tilting part, a second printing inspection part, A lower wiring pattern manufacturing part including a second drying part, a second light sintering part, and a wiring board recovery part may be included.

A method of manufacturing a wiring board using the apparatus 100 for manufacturing a wiring board according to the present exemplary embodiment will be described below with reference to FIGS. 1 to 7. 3 is a flowchart according to a method of manufacturing a wiring board using the ink composition for optical sintering according to the embodiment of the present invention. 4 to 7 are diagrams illustrating each step according to the manufacturing method of FIG. 3.

First, in step S81 to prepare an ink composition for light sintering. That is, silver oxide is mixed with nano copper oxide particles, a reducing agent, a dispersant, a binder, and a solvent to prepare an ink composition for photosintering. At this time, the materials constituting the ink composition for light sintering are first predispersed for 30 minutes to several hours by the predisperser. The materials that make up the pre-dispersed light sintering ink composition secondly again by three mills to form the light sintering ink composition can be mixed uniformly. In addition, the foreign matter and the aggregated material may be filtered from the mixed ink sintering ink composition to prepare an ink sintering composition for forming a final wiring pattern.

Next, the photo-sintered ink composition prepared in step S83 is aged at room temperature. That is, the ink composition for optical sintering prepared in step S81 is aging for several hours in an ambient temperature atmosphere. The aged light sintering ink composition is provided to the screen printing unit 20.

Next, as shown in FIG. 4, the substrate body 71 is supplied to the screen printing unit 20 through the wiring board supply unit 10. In this case, the substrate body 71 may be a semi-finished wiring board in which a wiring pattern is not formed on a surface facing the top, or a semi-finished wiring board in which a wiring pattern is formed on a surface facing the bottom of the substrate body 71. .

Next, as shown in FIG. 5, the preliminary wiring pattern 73 is formed by screen printing the ink composition 27 for photo sintering on the substrate body 71 in step S85. That is, when the substrate body 71 is transferred onto the stage, while the screen 21 is mounted on the substrate body 71, the ink composition 27 for optical sintering supplied to the screen 21 is pushed by the squeeze 25. The ink composition 27 for light sintering is filled into the pattern hole 23. By separating the screen 21 from the substrate body 71, the preliminary wiring pattern 73 may be formed on the substrate body 71.

For example, the preliminary wiring pattern 73 may be formed by screen printing on the substrate body 71 with a line width of 30 to 300 μm and a thickness of 5 to 20 μm. In this case, when the thickness of the preliminary wiring pattern 73 is 5 μm or less, there is a problem in that pulse control of white light generated from the xenon flash lamp is difficult, thereby deforming or damaging the shape of the wiring pattern manufactured by optical sintering. Can be generated. On the contrary, when the thickness of the preliminary wiring pattern 73 exceeds 20 μm, reduction and light sintering due to light irradiation may not be performed properly, resulting in an increase in resistance of the manufactured wiring pattern. That is, the specific gravity of the non-reduced nano copper oxide particles of the nano copper particles forming the preliminary wiring pattern 73 increases in proportion to the thickness.

Next, the preliminary wiring pattern 73 screen printed in step S87 is inspected. That is, the printing inspection unit 30 checks whether the printed state of the preliminary wiring pattern 73 on the substrate body 71 is properly printed using a camera.

Subsequently, as shown in FIG. 6, the preliminary wiring pattern 73 screen-printed in step S89 is dried. That is, the drying unit 40 dries and removes the solvent included in the preliminary wiring pattern 73 formed on the substrate body 71 on which the printing test process is completed. For example, the drying unit 40 may provide hot air or infrared rays of 60 to 100 ° C. to the preliminary wiring pattern 73 to dry and remove the solvent included in the preliminary wiring pattern 73.

As shown in FIG. 7, the preliminary wiring pattern 73 dried in step S91 is optically sintered to form the wiring pattern 75, thereby forming a wiring board having the wiring pattern 75 according to an exemplary embodiment of the present invention. 70) can be prepared. That is, the light sintering unit 50 irradiates monochromatic pulsed light to the dried preliminary wiring pattern 73 to reduce and sinter the oxidized copper of the nanocopper oxide particles included in the preliminary wiring pattern 73 to form the substrate body 71. The wiring pattern 75 can be formed on the substrate. For example, monochromatic pulsed light used in the manufacture of flexible printed circuit boards has a pulse width of 100 mW to 5000 mW, a pulse gap of 0.01 ms to 1 ms, an output voltage of 100 to 500 V, a number of pulses of 1 to 10 times and an intensity of 3 J / cm 2 White light of 60 J / cm 2 can be used.

Although the wiring board 100 manufactured by the manufacturing method according to the present embodiment has disclosed an example including the board body 71 and the wiring pattern 75 formed on the upper surface of the board body 71, the present invention is not limited thereto. It doesn't happen. For example, the wiring board may have a structure in which wiring patterns are formed on both surfaces of the substrate body 71. That is, when the substrate body 71 having the lower wiring pattern is formed on the lower surface through the wiring board supply unit 10, the upper wiring pattern is formed on the upper surface of the substrate body 71, whereby the wiring patterns are formed on both surfaces. Substrates can be prepared. Of course, the lower wiring pattern can also be formed with the ink composition for photo sintering according to the present embodiment.

According to the present embodiment, the wiring pattern 75 of the wiring board 70 is formed by using inexpensive nano copper oxide particles having a copper oxide film as a material of the ink composition for optical sintering, thereby manufacturing the wiring board 70. Can reduce the cost.

Also, after printing the ink composition 27 for photo sintering containing silver oxide and nano copper oxide particles on the wiring board 70, the surface of the nano copper oxide particles is sintered by short light irradiation instead of thermal sintering. Since the copper oxide film formed in the film can be removed, the process time can be shortened, and damage to the wiring substrate 70 can be suppressed by the sintering process through short light irradiation. At this time, the nano copper oxide particles are insulated before photo sintering, but are reduced to pure nano copper particles through photo sintering, thereby forming a wiring pattern 75 of a copper material having electrical conductivity.

Accordingly, the wiring pattern 75 may be formed on the substrate body 71 of the flexible printed circuit board used for the digitizer without damaging the substrate body 71 using the ink composition for optical sintering according to the present embodiment.

In addition, when the wiring pattern 75 is formed on the wiring board 70 by using the ink composition for optical sintering including nano copper particles having a copper oxide film, the wiring pattern 75 is formed to have a high aspect ratio by a screen printing method. can do. That is, since the signal transmission speed of the wiring board 70 depends on the resistance, it can be formed by the screen printing method so that the wiring pattern 75 has a high aspect ratio.

Moreover, since the ink composition for optical sintering which concerns on this invention contains silver oxide, compared with using nano copper oxide particle | grains independently, the density of a wiring pattern can be improved. That is, in the ink composition including only the nano copper oxide particles, a wiring pattern is formed in a form containing a plurality of pores therein due to the gas generated during the light sintering process. However, when silver oxide is included as in the present invention, since the amount of gas generated in the photo sintering process can be reduced to reduce the amount of pores that may exist in the wiring pattern, a wiring pattern with improved density can be formed. .

Since the ink composition for optical sintering which concerns on this invention contains silver oxide, compared with using nano copper oxide particle | grains independently, an optical sintering efficiency can be improved. That is, compared to the ink composition containing only nano copper oxide particles as copper particles, since the ink composition containing silver oxide has a high light absorption rate during photo sintering as in the present invention, the light sintering efficiency can be improved.

The wiring board 100 manufactured by the manufacturing method according to the present embodiment will be described with reference to FIGS. 8 and 9 as follows. 8 is a photograph showing a preliminary wiring pattern before light sintering. 9 is a photograph showing a wiring pattern after light sintering.

At this time, a wiring board was manufactured using the ink compositions according to Examples and Comparative Examples as follows.

Sample Applied voltage
(V) Pulse width Specific Light Energy (J / ㎠) Resistivity
(x10 ^-6 cm) Density before sintering (g / cm 3) Density after sintering (g / cm 3) Example 1 390 1500/500/200 38 2.7 4.1 8.9 Example 2 370 2200 27 2.5 3.8 9.1 Comparative Example 1 370 1500/500/200 38 4.7 4.2 8.2 Comparative Example 2 370 2200 27 5.3 4.2 8.0

Table 1 shows light irradiation energy and specific resistance during light sintering according to Examples and Comparative Examples. Novacentrics Pulse forge 1300 was used as the light sintering equipment used for light irradiation, and resistivity measurement was performed using 4-prob of LORESTA-GP.

Example 1

A silver oxide and a copper oxide film having a thickness of about 30 nm and a D ₅₀ of 100 nm are prepared for an ink composition for photo sintering in which the content of the metal particles in which the nanocopper oxide particles are hybridized is 80% by weight. At this time, the composition ratio of silver oxide and nano copper oxide particles is 2: 8.

A square pattern of 2 × 2 cm 2 was printed through a screen print (Sus 400 mesh, an emulsion thickness of 8 μm, a strap angle of 45 degrees), dried at 100 ° C. for 30 minutes, and optically sintered under the conditions shown in Table 1.

The print electrode was weighed and the density of the printed electrode after drying was measured by measuring the thickness of the electrode using a confocal microscope.

The result was a density of about 4.1 g / cm 3. After light sintering, the density increased to 8.9 g / cm 3, and the specific resistance was 2.7 × 10 ⁻⁶ dBm.

Example 2

A silver oxide and a copper oxide film having a thickness of about 30 nm and a D ₅₀ of 100 nm are prepared for an ink composition for photo sintering in which the content of the metal particles in which the nanocopper oxide particles are hybridized is 80% by weight. At this time, the composition ratio of silver oxide and nano copper oxide particles is 3: 7.

A square pattern of 2 × 2 cm 2 was printed through a screen print (Sus 400 mesh, emulsion thickness of 8 μm, strap angle of 45 degrees), dried at 100 ° C. for 30 minutes, and optically sintered under the conditions shown in Table 1.

The density of the printed electrode was measured after drying by weighing the printed electrode and measuring the thickness of the electrode using a confocal microscope.

The result was a density of about 3.8 g / cm 3. After light sintering, the density increased to 9.1 g / cm 3, and the specific resistance was 2.5 × 10 ⁻⁶ dBm.

Comparative Example 1

An ink composition is prepared in which the copper oxide film has a thickness of about 30 nm and a D ₅₀ of 100 nm, wherein the content of metal particles composed only of nano copper oxide particles is 80% by weight.

A square pattern of 2 × 2 cm 2 was printed through a screen print (Sus 400 mesh, an emulsion thickness of 8 μm, a strap angle of 45 degrees), dried at 100 ° C. for 30 minutes, and optically sintered under the conditions shown in Table 1. At this time, the light irradiation conditions are the same as in Example 1.

The print electrode was weighed and the density of the printed electrode after drying was measured by measuring the thickness of the electrode using a confocal microscope.

The result was a density of about 4.2 g / cm 3. After light sintering, the density increased to 8.2 g / cm 3, and the specific resistance was 4.7 × 10 ⁻⁶ dBm.

Comparative Example 2

An ink composition is prepared in which the copper oxide film has a thickness of about 30 nm and a D ₅₀ of 100 nm, wherein the content of metal particles composed only of nano copper oxide particles is 80% by weight.

A square pattern of 2 × 2 cm 2 was printed through a screen print (Sus 400 mesh, an emulsion thickness of 8 μm, a strap angle of 45 degrees), dried at 100 ° C. for 30 minutes, and optically sintered under the conditions shown in Table 1. At this time, the light irradiation conditions are the same as in Example 2.

The print electrode was weighed and the density of the printed electrode after drying was measured by measuring the thickness of the electrode using a confocal microscope.

The result was a density of about 4.2 g / cm 3. After light sintering, the density increased to 8.0 g / cm 3, and the specific resistance was 5.3 × 10 ⁻⁶ dBm.

As described above, it was confirmed that the pattern formed using the ink compositions for photo sintering according to Examples 1 and 2 had a lower specific resistance and higher density after photo sintering than the ink compositions of Comparative Examples 1 and 2.

On the other hand, the embodiments disclosed in the specification and drawings are merely presented specific examples to aid understanding, and are not intended to limit the scope of the invention. It is apparent to those skilled in the art that other modifications based on the technical idea of the present invention can be carried out in addition to the embodiments disclosed herein.

10: wiring board supply unit
20: screen printing unit
21: Screen
23: pattern hole
25: squeeze
27: ink composition for light sintering
30: printing inspection unit
40: drying unit
50: light sintered part
60: wiring board recovery unit
70: wiring board
71: substrate body
73: preliminary wiring pattern
75: wiring pattern
100: apparatus for manufacturing wiring board

Claims (6)

Silver oxide includes nano copper oxide particles having a copper oxide film on the outside, a reducing agent, a dispersant, a binder and a solvent for reducing the nano copper oxide particles to nano copper particles upon light irradiation,
The composition ratio of the silver oxide and the nano copper oxide particles is 0.1: 9.9 to 4: 6,
The silver oxide powder has a size of 2 μm or less, and the nano copper oxide particles have a D ₅₀ of 900 nm or less and a Dmax of 2 μm or less. delete The method of claim 1,
Silver oxide and nano copper oxide particles other than the solvent is 70 to 94% by weight of the ink composition for light sintering. delete The method of claim 1,
The reducing agent includes an aldehyde compound, an acid containing ascorbic acid, a phosphorus compound, a metal reducing agent, p-benzoquinone, hydroquinone or anthraquinone,
The dispersant includes a cationic dispersant, an anionic dispersant or a zwitterionic dispersant,
The binder is PVP, PVA and PVC, cellulose resin, polyvinyl chloride resin, copolymer resin, polyvinyl alcohol resin, polyvinylpyrrolidone resin, acrylic resin, vinyl acetate-acrylic acid ester copolymer resin, butyral resin, alkyd Resin, epoxy resin, phenol resin, rosin ester resin, polyester resin or silicone,
The solvent is ethylene glycol (EG), diethylene glycol (DEG), dibasic ester (DBE), carbitol acetate (CA), dipropylene glycol methyl ether (Dipropylene glycol methyl ether; DPM or DPGME), butyl carbitol acetate (BCA), butyl carbitol (BC), texanol, terpineol or butyl acrylate; Ink composition for optical sintering containing BA). Screen printing ink sintering ink composition comprising silver oxide on the flexible substrate body, nano copper oxide particles having a copper oxide film on the outside, a reducing agent, a dispersant, a binder, and a solvent for reducing the nano copper oxide particles to nano copper particles upon light irradiation. Screen printing to form a preliminary wiring pattern;
A drying step of drying the screen printed preliminary wiring pattern;
And a light sintering step of irradiating light on the dried preliminary wiring pattern to reduce and sinter the oxidized copper of the nanocopper oxide particles included in the preliminary wiring pattern to form a wiring pattern on the substrate body.
The composition ratio of the silver oxide and the nano copper oxide particles in the ink composition for optical sintering is 0.1: 9.9 to 4: 6,
The silver oxide powder has a size of 2㎛ or less, the nano-copper oxide particles D ₅₀ is 900nm or less Dmax is 2㎛ or less method for producing a wiring board using an ink composition for optical sintering.

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