KR20160056861A - digitizer flexible printed circuits board using light sintering and method for manufacturing thereof - Google Patents

Abstract

The present invention relates to a digitizer flexible printed circuit board using light sintering and a method of fabricating the same. The digitizer flexible printed circuit can be produced by a printing process using conductive composite ink. Production costs can be reduced by the simplified process and improved work convenience, and the process is more environmentally-friendly in comparison with conventional photolithography. In addition, since surface tension and viscosity of the conductive composite ink can be effectively controlled with a solvent and a binder, various printing processes can be carried out and, especially, a high-speed roll-to-roll (R2R) process may be used in gravure or a flexography printing. Thus, a large-area digitizer flexible printed circuit board may be fabricated.

Description

TECHNICAL FIELD [0001] The present invention relates to a digitizer flexible printed circuit board using photo-sintering and a method of manufacturing the same,

The present invention relates to a digitizer flexible printed circuit board using photo-sintering and a method of manufacturing the same.

Recently, with the development of electronic engineering and information technology, the use of portable electronic devices has been steadily increasing. Thus, a touch screen panel capable of intuitive input, high durability, multi-touch, and thinness is widely popular as an input device. The touch screen panel is installed in the display device to sense the position on the screen that the user touches and controls the electronic device including the screen control of the display based on the input information. The touch screen panel facilitates interoperability with many electronic devices .

The touch screen panel has electrostatic capacity and electromagnetic induction. The capacitive method is a method of detecting capacitance by using capacitance coupling in the state that an AC voltage is applied. It has a high durability and is capable of multi-touch as well as being able to operate with fingertips without a simple tool , It is difficult to detect fine touches, and there is a disadvantage in that multi-touch is possible but it is not possible to select an accurate point.

On the other hand, the electromagnetic induction method is a method of sensing the electromagnetic force generated from the touch sensor and the exclusive pen (electronic pen), and it is possible to recognize the strength of the pressure of the exclusive pen and to perform operations such as right and left clicking . This is not possible with the multi-touch function, but since it is possible to perform fine manipulation considering the pressure like a brush, such an electromagnetic induction type digitizer is preferred.

The digitizer type touch screen panel digitally detects and coordinates the position of a pointing device such as a dedicated pen located on a specially manufactured panel, Convenient and precise input is possible.

Such an electromagnetic induction type digitizer is equipped with a plurality of coils on a digitizer substrate and detects the electromagnetic change caused by the approach of the pen to grasp the position of the pen. Therefore, unlike the resistance film type, As shown in FIG.

A flexible printed circuit board (FPCB) constituting the digitizer is generally manufactured by a photolithography process.

Since the photolithography process is composed of more than two stages, the process is complicated, the unit cost is high, the process is performed for a long time, and many toxic chemicals are used during the process, thereby causing environmental pollution. In addition, flexible polymer substrates such as polyethylene terephthalate (PET), polyimide (PI), and photopaper can not withstand the etching solution used in the photolithography process. In order to maintain the state of the inert gas, There is a problem that a chamber is required (Patent Document 1).

Patent Document 1: Korean Patent Laid-Open Publication No. 1997-0028972

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a conductive composite ink which can be produced by a direct printing method, light sintering to at least one selected from extreme ultraviolet light, near infrared light and far ultraviolet light, And a method of manufacturing the same.

In order to achieve the above object, the present invention provides a semiconductor device comprising: a substrate; And a pattern of an electrode shape formed on an upper surface or a back surface of the substrate, wherein the pattern includes at least one first metal particle or at least one second metal particle selected from metal microparticles, metal nanowires, The present invention provides a digitized flexible printed circuit board manufactured by printing a conductive composite ink containing metal particles on a substrate and photo-sintering the conductive composite ink into at least one selected from extreme ultraviolet light, near-infrared light and far ultraviolet light.

The substrate may be a photographic paper, a paper, a glass, a polybutylene terephthalate (PBT), a polyethylene terephthalate (PET), a polysulfone, a polyether, a polyetherimide (PEI), a polyethylene naphthalate (PEN) 1 selected from acrylic resin, heat resistant epoxy, BT epoxy / glass fiber, PVAC, butyl rubber resin, polyarylate (PAR), polyimide (PI), silicone, ferrite, It can be all day.

The printing can be carried out by a direct printing method, such as screen printing, inkjet printing, micro-contact printing, imprinting, gravure printing, gravure-offset printing gravure-offset printing, flexography printing, and spin coating.

The first metal particles and the second metal particles may be at least one selected from the group consisting of Cu, Au, Ag, Ni, Pt, Co, Fe, , Tungsten (W), molybdenum (Mo), manganese (Mn), chromium (Cr), zinc (Zn) and aluminum (Al).

The metal precursor may be a _{Cu (NO 3) 2 · 3H} 2 O.

The pattern may be a mesh pattern.

The first metal particles may have a diameter of 20-50 nm, the metal microparticles may have a diameter of 1-10 μm, and the metal nanowires may have a diameter of 10-500 nm and a length of 1-100 μm.

The conductive composite ink may further comprise a binder and a solvent, and the binder may be at least one selected from polyvinylpyrrolidone (PVP), azobis, sodium dodecylbenzene sulfate, and polyethylene glycol.

The first and second metal particles may be made of one kind selected from an electric wire explosion method, a plasma heating method, an electrolysis method, and a chemical synthetic method.

The sheet resistance of the digitizer flexible printed circuit board may be 0.01-0.5 Ohm / sq.

In order to achieve the above object,

I) preparing a substrate;

II) forming a pattern by printing with a conductive composite ink on an upper surface or a back surface of the substrate;

III) drying the pattern by one or more methods selected from infrared rays, hot plates and ovens;

(Iv) photo-sintering the dried pattern by at least one method selected from extreme ultraviolet light, near-infrared light and deep ultraviolet light.

The substrate may be a photographic paper, a paper, a glass, a polybutylene terephthalate (PBT), a polyethylene terephthalate (PET), a polysulfone, a polyether, a polyetherimide (PEI), a polyethylene naphthalate (PEN) 1 selected from acrylic resin, heat resistant epoxy, BT epoxy / glass fiber, PVAC, butyl rubber resin, polyarylate (PAR), polyimide (PI), silicone, ferrite, It can be all day.

In the step (II), dispersing the conductive composite ink into at least one selected from an ultrasonic dispersing machine, a stirrer, a ball mill, and a 3 roll mill; And a step of defoaming.

The conductive composite ink may include a first metal particle alone or a first metal particle and at least one second metal particle selected from a metal microparticle, a metal nanowire, and a metal precursor.

The first metal particles and the second metal particles may be at least one selected from the group consisting of Cu, Au, Ag, Ni, Pt, Co, Fe, , Tungsten (W), molybdenum (Mo), manganese (Mn), chromium (Cr), zinc (Zn) and aluminum (Al).

The first metal particles may have a diameter of 20-50 nm, the metal microparticles may have a diameter of 1-10 μm, and the metal nanowires may have a diameter of 10-200 nm and a length of 1-10 μm.

If the second metal particles are metal precursors, the weight ratio of the first metal particles to the second metal particles may be 1: 0.1 to 0.5,

If the second metal particles are metal microparticles, the weight ratio of the first metal particles to the second metal particles may be 1: 0.01 to 0.1,

If the second metal particles are metal nanowires, the weight ratio of the first metal particles to the second metal particles may be 1: 1 to 3: 1.

In the step (IV), the light sintering may be performed by simultaneously irradiating one or more light sources selected from extreme ultraviolet light, near-infrared light and far ultraviolet light, or by stepwise irradiation.

When the light sintering condition is the pulse number of the xenon flash lamp is 1 to 20, the pulse width may be 5-20 ms and the intensity may be 5-15 J / cm 2.

The intensity of the far ultraviolet ray may be 10-50 mW / cm 2, and the intensity of the near-infrared ray may be 10-100 mW / cm 2.

The step (III) may further include a preliminary light irradiation step for preheating or solvent drying.

The digitized flexible printed circuit board (FPCB) of the present invention uses a conductive composite ink and can be produced by a printing process, thereby simplifying the process and improving the convenience of operation, thereby reducing the cost of the process. In addition to the conventional photolithography process It is environmentally friendly.

Further, since the present invention can effectively control the surface tension and viscosity of the conductive composite ink using a solvent and a binder, various printing processes can be performed, and in particular, gravuring, flexography ), It is possible to apply a high-speed roll-to-roll (R2R) process, and thus it is possible to manufacture a large-area digitizer flexible printed circuit board.

Further, the present invention can reduce and sinter at a very short sintering time at room temperature / atmospheric conditions by using a conductive composite ink and a light sintering system using at least one light source selected from extreme ultraviolet light, near-infrared light and far ultraviolet light , The degree of damage of the substrate is low, and the electrical conductivity and the mechanical strength of the pattern are excellent. Therefore, the pattern formed on the flexible substrate has an advantage of preventing pattern breakage due to folding or shrinkage.

1 is a flowchart illustrating a method of manufacturing a digitizer flexible printed circuit board according to the present invention.
2 is an illustration of an example of a digitizer flexible printed circuit board according to the present invention.
FIG. 3 is an exemplary view showing a case where high-speed roll-to-roll (R2R) is applied in a method for manufacturing a digitizer flexible printed circuit board according to the present invention.
4 is an exemplary view showing an apparatus for photo-sintering a conductive composite ink according to the present invention into extreme ultraviolet and white light. Here, (1) shows the crystal structure of the conductive composite ink before sintering, and (2) shows the crystal structure of the conductive composite ink after sintering.
5 is an exemplary view showing a light sintering apparatus capable of irradiating extreme ultraviolet light, far ultraviolet light and near-infrared light simultaneously according to the present invention.
6 is a graph of a single pulse white light of a xenon lamp according to the present invention.
7 is a graph showing measured sheet resistances when printing and applying conductive composite inks of various compositions to produce a digitizer flexible printed circuit board according to the present invention. In this case, Examples 5, 13, 14, 11, 12, 9 and Comparative Examples 1, 2, 3 are shown in order from the left side of the graph.
Fig. 8 is a graph showing the results of the SEM (a) and the photo-sintering (b) of the conductive composite ink containing copper nanoparticles prepared by the plasma heating method according to the present invention (Example 15) before photo- It is a photograph.
FIG. 9 is a graph showing the results of a comparison between the SEM (a) and the photo-sintering (b) of the conductive composite ink containing copper nanoparticles prepared by the electric wire explosion method according to the present invention (Example 16) before photo- It is a photograph.
10 is a graph showing the sheet resistance of each of the digitizer flexible printed circuit boards manufactured by printing conductive composite inks of various compositions according to the present invention on a substrate and photo-sintering the same on various conditions.
11 is a photograph showing a printing method using a conductive composite ink on various flexible substrates and a method of a digitizer flexible printed circuit board according to the present invention (a) and (b) before photo-sintering.
12 shows X-ray diffraction analysis results of the conductive composite ink according to the present invention before and after photo-sintering.
Fig. 13 is a graph showing the results of measurement of the dielectric constant of the digitized flexible printed circuit board (manufactured by Fuji Photo Film Co., Ltd.) manufactured from Example 1 (), Example 17 (), Example 18 (The second copper particles are copper nanowires) after 1000 times of repeated outer bending tests.

Hereinafter, various aspects and various embodiments of the present invention will be described in more detail.

In the digitizer function of the present invention, a digitizer flexible printed circuit board is provided on the lower side of the touch screen / display panel, and a thin metal wiring is formed on the digitizer flexible printed circuit board. At the end of the digitizer pen, an ultra-small metal coil is built in which an alternating magnetic field is generated. Therefore, when the tip of the electronic pen approaches the touch screen, electromagnetic induction phenomenon occurs, and the electromagnetic field already formed on the digitizer flexible printed circuit board disposed on the lower side of the touch screen / display panel is deformed and sensed through the sensor disposed at one corner And the motion of the actual electronic pen is analyzed.

Such a digitizer printed circuit board has been manufactured through a photolithography process which has been made up to about 12 steps to date.

The digitizer can be used not only in a technical field such as a large-format tablet, a PC, and a TV, but also in a variety of industrial fields such as flexible electronic products, flexible electronic products (Wearable Electronics) (FPCB) to be applied to the field

However, since the photolithography process includes an etching process and a high-temperature firing process, the substrate may be a photographic paper, a paper, a polybutylene terephthalate (PBT), a polyethylene terephthalate (PET), a polyetherimide (PEI), polyimide (PI) and FR-4 are used, there is a problem that the substrate is damaged and the pattern is also easily broken by bending or shrinkage due to heat since the pattern has a weak mechanical strength .

Therefore, in order to solve the above problems, the present invention has completed an improved composite printed circuit board and a method of manufacturing the same, which is manufactured through a printing composite process and a light sintering process.

First, one aspect of the present invention relates to a semiconductor device comprising: a substrate; And a pattern of an electrode shape formed on an upper surface or a back surface of the substrate, wherein the pattern includes at least one first metal particle or at least one second metal particle selected from metal microparticles, metal nanowires, Wherein the conductive composite ink is printed on the substrate and photo-sintered to at least one selected from extreme ultraviolet light, near-infrared light and far ultraviolet light, to a digitizer flexible printed circuit board .

The pattern formed on the substrate is not particularly limited, but a mesh pattern is the most preferable form for performing the function of the digitizer.

The substrate may be a rigid or flexible substrate, but preferably a photo paper, paper, glass, polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polysulfone, (PE), polyethylene naphthalate (PEN), acrylic resin, heat resistant epoxy, BT epoxy / glass fiber, PVAC, butyl rubber resin, polyarylate (PAR), polyimide , Ferrite, ceramic, and FR-4, and more preferably, a flexible substrate capable of producing a digitizer having excellent flexibility can be used. For example, it may be one selected from the group consisting of polyimide (PI), photographic paper (Photo Paper), polyethylene terephthalate (PET), polyetherimide (PEI) and FR-4.

The printing can be carried out by a direct printing method, such as screen printing, inkjet printing, micro-contact printing, imprinting, gravure printing, gravure-offset printing gravure printing, gravure-offset printing, flexography printing and spin coating. In order to perform the high-speed roll-to-roll (R2R), gravure printing, gravure- gravure-offset printing, and flexography printing are most preferably used.

In the conductive composite ink, the first metal particles and the second metal particles may be at least one selected from the group consisting of Cu, Au, Ag, Ni, Pt, Co, At least one selected from cadmium (Cd), tungsten (W), molybdenum (Mo), manganese (Mn), chromium (Cr), zinc (Zn) and aluminum It is most preferable to use copper because it is excellent, is inexpensive, and has a low resistance and a decrease in conductivity due to bending when formed in a pattern on a flexible substrate.

Wherein it is preferable to use the metal precursor copper precursor from the second metal particles in the copper precursor is _{CuCl, CuCl 2, Cu (acac} ) 2, Cu (hfac) 2, Cu (tfac) 2, Cu (dpm) _{2, Cu (ppm) 2,} Cu (fod) 2, Cu (acim) 2, Cu (nona-F) 2, Cu (acen) 2, Cu (NO 3) 2 and _{3H 2 O, Cu (C 3} H ₄ F ₃ O ₂ ) ₂ and CuSO ₄ ㅇ 5H ₂ O, which may be appropriately selected depending on the solvent used. For example, when diethylene glycol (DEG) is used as a solvent in the conductive composite ink of the present invention, it is most preferable to use Cu (NO ₃ ) ₂ .3H ₂ O. This is because the sheet resistance is significantly superior to the other precursors, and the sheet resistance comparison of the metal precursor can be seen in FIG.

The diameter of the first metal particles may be 20-50 nm. If the diameter of the first metal particles is less than the above range, an ink having poor dispersibility is produced. If the first metal particles exceed the above- If the size of the pores generated between the first metal particles and the second metal particles during the sintering process is too large, the resistance is increased and the conductivity is lowered, so that it is not suitable for use as a conductive ink.

The second metal particles used in the present invention may be at least one selected from metal microparticles, metal nanowires, and metal precursors.

Especially. When the conductive composite ink including the first metal particles and the metal microparticles as the second metal particles is sintered, a necking is formed between the second metal particles having a large size and the first metal particles having a size of nano- Since the generated pores can be reduced, the sheet resistance is lowered, the conductivity is improved, and the durability is also improved.

When the second metal particles are metal microparticles, the diameter of the second metal particles is preferably 1-10 占 퐉. If the size of the metal microparticles is less than 1 占 퐉, the conductivity is not excellent, A plasmon (light resonance phenomenon) phenomenon is not generated and conductivity and sintering efficiency are deteriorated. In addition, when the size of the metal microparticles exceeds 10 탆, the energy required for sintering increases, so that the generated pattern may be damaged and the conductivity may be lowered.

When the second metal particles are metal nanowires, the first metal particles and the nanowires are formed by forming a linking ring together with each other, so that durability is improved and the rate of increase in resistance can be lowered.

Further, when the metal microparticles and the metal nanowires are mixed with the second metal particles, the pores may be degraded due to the use of the nanoparticles and the microparticles, and at the same time, It is most suitable for a flexible digitizer flexible printed circuit board because it has the advantage of maintaining the conductivity even if breakage occurs in the pattern due to shrinkage.

The diameter of the metal nanowire may be 10-500 nm and the length may be 1-100 mu m. If the diameter and length are less than the above range, the conductivity is not excellent. If the diameter and length exceed the above range, the energy required for sintering As a result, the substrate may be damaged and a pattern with reduced conductivity may be generated.

The conductive composite ink may further include a binder and a solvent. The binder is for improving the dispersibility and reducibility of the ink during the production of the conductive composite ink. Preferably, the binder is a polyvinyl pyrrolidone, a polyvinyl alcohol, a polyvinyl And polymeric binders such as butyral, polyethylene glycol, polymethyl methacrylate, dextran, azobis, sodium dodecylbenzenesulfate, and the like.

The binder may be included in an amount of 1 to 50 parts by weight based on 100 parts by weight of the conductive composite ink. If the content of the binder is less than 1, the dispersibility or reducing property is lowered, do. When the content of the binder is more than 50 parts by weight, aggregates are preferably formed.

The conductive composite ink further includes a dispersing agent, and the dispersing agent may include a copolymer containing ionic groups such as Disperbyk 180, Disperbyk 111, and styrene maleic anhydride copolymer (SMA 1440 flake); Propylene glycol monoethyl ether acetate, ethylene glycol butyl ether, cyclohexanone, cyclohexanol, 2-ethoxyethyl acetate, ethylene glycol diacetate, terpineol (terpineol), and isobutyl alcohol.

In addition, the viscosity and surface tension can be controlled by suitably adjusting the solvent. Examples of the solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, glycerin, isopropyl alcohol, butyl alcohol, octyl alcohol, formamide, methyl ethyl ketone, , Methyl alcohol, and acetone.

It is preferable that the first and second metal particles are made of one kind selected from an electric wire explosion method, a plasma heating method, an electrolysis method and a chemical synthetic method.

The pattern of the digitizer flexible printed circuit board may irradiate at least one light source selected from extreme ultraviolet light, near-infrared light (NIR), and deep ultraviolet light (Deep UV). By such local melting, The present invention can provide a digitizer flexible printed circuit board excellent in conductivity and durability because the first metal particles and the second metal particles and the metal particles and the substrate are optically bonded to each other to facilitate texture densification.

Therefore, a digitizer flexible printed circuit board having excellent conductivity and durability while minimizing damage to the substrate through the conductive composite ink and the light sintering step of the present invention, rather than the digitizer flexible printed circuit board manufactured by applying the printing method for improving the simple photolithography process, A circuit board can be provided.

At this time, it is possible to sinter the pattern having low resistance only when sufficient energy is irradiated according to the substrate on which the pattern is formed.

More specifically, it is preferable that the light sintering condition is such that the pulse width is 5-20 ms and the intensity is 1-50 J / cm 2 when the number of pulses of the xenon flash lamp is 1 to 20, The range may vary.

When the substrate is PET, the energy range is 5-20 J / cm 2. When the substrate is PI, the energy range is 5-50 J / cm 2. In the case of photographic paper, the energy range is 3-15 J / , It is preferable that the energy range is 10-20 J / cm < 2 >. When the energy range condition is exceeded, it can be confirmed that the sheet resistance is significantly increased.

If the energy range is exceeded, the substrate is damaged. Therefore, the function of the digitizer deteriorates and detailed touch becomes impossible. In particular, when the energy range is exceeded, the flexibility and bending characteristics of the flexible substrate are remarkably deteriorated due to the damage of the substrate, and if it is applied to a product, it is easily broken and errors occur.

The intensity of the far ultraviolet ray may be 1-5000 mW / cm 2 for 0-300 seconds, and the intensity of near infrared rays may be 0.1-3000 W / cm 2 for 0-1000 seconds.

When the infrared irradiation energy is irradiated below the above range, it takes a long time to improve the temperature of the substrate and the coating layer. If the infrared irradiation energy is over the above range, the temperature of the substrate may become too high in a short time, .

The digitizer flexible printed circuit board manufactured by printing a pattern with the conductive composite ink on the flexible substrate and photo-sintering the pattern with the conductive composite ink has a remarkably low sheet resistance of 0.01-0.5? / Sq, And a low resistance increase rate.

Still another aspect of the present invention relates to a method of manufacturing the digitizer flexible printed circuit board including the steps of:

(I) preparing a substrate,

(II) printing a conductive composite ink on an upper surface or a back surface of the substrate to form a pattern,

III) drying the pattern by at least one method selected from infrared rays, hot plates and ovens,

IV) Photo-sintering the dried pattern by at least one method selected from extreme ultraviolet light, near-infrared light and far ultraviolet light.

The substrate may be a photographic paper, a paper, a glass, a polybutylene terephthalate (PBT), a polyethylene terephthalate (PET), a polysulfone, a polyether, a polyetherimide (PEI), a polyethylene naphthalate (PEN) 1 selected from acrylic resin, heat resistant epoxy, BT epoxy / glass fiber, PVAC, butyl rubber resin, polyarylate (PAR), polyimide (PI), silicone, ferrite, It can be all day.

The printing can be carried out by a direct printing method, such as screen printing, inkjet printing, micro-contact printing, imprinting, gravure printing, gravure-offset printing gravure-offset printing, flexography printing, and spin coating.

Dispersing the conductive composite ink into at least one selected from an ultrasonic dispersing machine, a stirrer, a ball mill, and a 3 roll mill; And a defoaming step.

The conductive composite ink is preferably soaked in water at 70 to 100 ° C for 3 to 5 hours before being coated on the substrate. When the conductive composite ink is coated on the substrate without being hot-watered, a mixture of metal nanoparticles, metal microparticles, metal nanowires, and metal precursors contained in the conductive composite ink may be clustered in various places.

The conductive composite ink may further include a binder and a solvent. The binder is for improving the dispersibility and reducibility of the ink during the production of the conductive composite ink. Preferably, the binder is a polyvinyl pyrrolidone, a polyvinyl alcohol, a polyvinyl And polymeric binders such as butyral, polyethylene glycol, polymethyl methacrylate, dextran, azobis, sodium dodecylbenzenesulfate, and the like.

The binder may be included in an amount of 1 to 50 parts by weight based on 100 parts by weight of the conductive composite ink. If the content of the binder is less than 1, the dispersibility or reducing property is lowered, do. When the content of the binder is more than 50 parts by weight, aggregates are preferably formed.

The conductive composite ink further includes a dispersing agent, and the dispersing agent may include a copolymer containing ionic groups such as Disperbyk 180, Disperbyk 111, and styrene maleic anhydride copolymer (SMA 1440 flake); Propylene glycol monoethyl ether acetate, ethylene glycol butyl ether, cyclohexanone, cyclohexanol, 2-ethoxyethyl acetate, ethylene glycol diacetate, terpineol (terpineol), and isobutyl alcohol.

Further, the viscosity and the surface tension can be controlled by appropriately adjusting the solvent. Examples of the solvent include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, glycerin, isopropyl alcohol, butyl alcohol, octyl alcohol, formamide, methyl ethyl ketone, , Methyl alcohol, and acetone.

Also, the conductive composite ink may include at least one first metal particle or at least one second metal particle selected from the group consisting of metal microparticles, metal nanowires, and metal precursors.

It is preferable that the first and second metal particles are made of one kind selected from an electric wire explosion method, a plasma heating method, an electrolysis method and a chemical synthetic method.

In the conductive composite ink, the first metal particles and the second metal particles may be at least one selected from the group consisting of copper (Cu), gold (Au), silver (Ag), nickel (Ni), platinum (Pt), cobalt ), Cadmium (Cd), tungsten (W), molybdenum (Mo), manganese (Mn), chromium (Cr), zinc (Zn) and aluminum It is most preferable to use copper because the increase in resistance due to bending and the decrease in conductivity are the lowest when the copper foil is the most excellent and has a low cost and is formed into a pattern on a flexible substrate.

Wherein it is preferable to use the metal precursor copper precursor from the second metal particles in the copper precursor is _{CuCl, CuCl 2, Cu (acac} ) 2, Cu (hfac) 2, Cu (tfac) 2, Cu (dpm) _{2, Cu (ppm) 2,} Cu (fod) 2, Cu (acim) 2, Cu (nona-F) 2, Cu (acen) 2, Cu (NO 3) 2 and _{3H 2 O, Cu (C 3} H ₄ F ₃ O ₂ ) ₂ and CuSO ₄ ㅇ 5H ₂ O, which may be appropriately selected depending on the solvent used. For example, when diethylene glycol (DEG) is used as a solvent in the conductive composite ink of the present invention, it is most preferable to use Cu (NO ₃ ) ₂ .3H ₂ O. This is because the sheet resistance is remarkably superior to other precursors, and the sheet resistance comparison according to the metal precursor can be confirmed in FIG.

The diameter of the first metal particles may be 20-50 nm. If the diameter of the first metal particles is less than the above range, an ink having poor dispersibility is produced. If the first metal particles exceed the above- If the size of the pores generated between the first metal particles and the second metal particles during the sintering process is too large, the resistance is increased and the conductivity is lowered, so that it is not suitable for use as a conductive ink.

The second metal particles used in the present invention may be at least one selected from metal microparticles, metal nanowires, and metal precursors.

Especially. When the conductive composite ink including the first metal particles and the metal microparticles as the second metal particles is sintered, a necking is formed between the second metal particles having a large size and the first metal particles having a size of nano- Since the generated pores can be reduced, the sheet resistance is lowered, the conductivity is improved, and the durability is also improved.

When the second metal particles are metal microparticles, the diameter of the second metal particles is preferably 1-10 占 퐉. If the size of the metal microparticles is less than 1 占 퐉, the conductivity is not excellent, A plasmon (light resonance phenomenon) phenomenon is not generated and conductivity and sintering efficiency are deteriorated. In addition, when the size of the metal microparticles exceeds 10 탆, the energy required for sintering increases, so that the generated pattern may be damaged and the conductivity may be lowered.

When the second metal particles are metal nanowires, the first metal particles and the nanowires are formed by forming a linking ring together with each other, so that durability is improved and the rate of increase in resistance can be lowered.

Further, when the metal microparticles and the metal nanowires are mixed with the second metal particles, the pores may be degraded due to the use of the nanoparticles and the microparticles, and at the same time, It is most suitable for a flexible digitizer flexible printed circuit board because it has the advantage of maintaining the conductivity even if breakage occurs in the pattern due to shrinkage.

The diameter of the metal nanowire may be 10-500 nm and the length may be 1-100 mu m. If the diameter and length are less than the above range, the conductivity is not excellent. If the diameter and length exceed the above range, the energy required for sintering As a result, the substrate may be damaged and a pattern with reduced conductivity may be generated.

If the second metal particles are metal precursors, the weight ratio of the first metal particles to the second metal particles may be 1: 0.1 to 0.5,

If the second metal particles are metal microparticles, the weight ratio of the first metal particles to the second metal particles may be 1: 0.01 to 0.1,

If the second metal particles are metal nanowires, the weight ratio of the first metal particles to the second metal particles is preferably 1: 1 to 3: When the ratio is less than the above range, the conductive composite ink has a high resistivity, and the surface state after printing is uneven and the conductivity is lowered. If the ratio of the first metal particles to the second metal particles exceeds the above range, the sintering efficiency and durability are lowered, and the pattern is easily broken due to bending and contraction of the flexible substrate.

Next, (II) a conductive composite ink is printed on the upper or rear surface of the substrate to form a pattern.

At this time, the printing may be a direct printing method, such as screen printing, inkjet printing, micro-contact printing, imprinting, gravure printing, gravure offset printing, Gravure printing, gravure-offset printing, flexography printing and spin coating. In order to perform the high-speed roll-to-roll (R2R), gravure printing, gravure- It is most preferable to use one kind selected from gravure-offset printing and flexography printing.

Next, (III) the pattern is dried by at least one method selected from an infrared ray, a hot plate and an oven.

If the solvent contained in the pattern is not properly dried through this process, sintering may not be performed properly since the ink is consumed a lot of energy in the phase change from the liquid phase to the solid phase at the subsequent light sintering.

At this time, it is preferable to maintain the soft substrate at 60-150 占 폚 so as not to damage the flexible substrate.

In addition, the step (III) may further include a preliminary light irradiation step for preheating or solvent drying. This is a preheating or preliminary light irradiation step performed in order to further refine the crystal state and arrangement state of the pattern made of the conductive ink applied to the substrate in the light sintering step to be performed subsequently.

This process can be performed by adjusting the extreme ultraviolet ray irradiation conditions or by irradiating near infrared rays. When the preheating or preliminary light irradiation is performed, the near-infrared light may be irradiated for 5 to 300 seconds at an intensity of 100 to 5000 mW / cm 2.

If the conductive composite ink applied to the substrate is not properly dried, the first and second metal particles may not be easily joined because the energy is consumed to change the phase from the liquid phase to the solid phase in the subsequent light sintering step. In addition, since the arrangement and the structure between the first and second metal particles are densified by such bonding, the size of the pores is reduced, so that a digitizer flexible printed circuit board with improved conductivity and durability can be obtained.

Next, (IV) the dried pattern is photo-sintered by at least one method selected from extreme ultraviolet light, near-infrared light and far ultraviolet light.

The light sintering may be performed by simultaneously irradiating one or more light sources selected from extreme ultraviolet light, near-infrared light and far ultraviolet light, or by stepwise irradiation.

According to the present invention, complete sintering is possible for a very short time of about 1 to 20 ms. The general structure of the extreme ultraviolet light sintering apparatus using the xenon lamp used in the present invention is shown in Fig.

The conductive composite ink coated on the substrate is subjected to light sintering while being subjected to light energy by extreme ultraviolet white light emitted from the xenon lamp, and thus becomes conductive. At this time, the necking is formed between the first metal particles and the second metal particles to improve the conductivity. 4 shows the state before and after the sintering of the conductive composite ink in which metal microparticles were used as the first metal particles and the second metal particles, and confirmed that the necking was formed between the first and second metal particles .

When the number of pulses of the xenon flash lamp in the light sintering step is 1 to 20, the pulse width may be 5-20 ms and the intensity may be 1-50 J / cm 2. If the pulse width is larger than 15 ms, When the number of pulses exceeds 20, the conductive composite ink does not sinter properly due to too low energy to form a uniform pattern even if the intensity is less than 0.01 J / cm 2. If the intensity is greater than 50 J / cm 2, equipment and lamps are burdened, and the service life of equipment and lamps is rapidly reduced.

The light sintering conditions of the extreme ultraviolet light using the xenon flash lamp are such that the energy range to be irradiated is controlled according to the type of the substrate, the energy range is 5-20 J / cm 2 when the substrate is PET, It is preferable that the energy range is from 3 to 15 J / cm 2 in the case of photographic paper, and the energy range is from 10 to 20 J / cm 2 in case of BT. , It can be confirmed that the sheet resistance is significantly increased.

If the energy range is exceeded, the substrate is damaged. Therefore, the function of the digitizer deteriorates and detailed touch becomes impossible. In particular, when the energy range is exceeded, the flexibility and bending characteristics of the flexible substrate are remarkably deteriorated due to the damage of the substrate, and if it is applied to a product, it is easily broken and errors occur.

The intensity of the far ultraviolet ray may be 1-5000 mW / cm 2 for 0-300 seconds, and the intensity of near infrared rays may be 0.1-3000 W / cm 2 for 0-1000 seconds.

When the infrared irradiation energy is irradiated below the above range, it takes a long time to improve the temperature of the substrate and the coating layer. If the infrared irradiation energy is over the above range, the temperature of the substrate may become too high in a short time, .

Particularly, when a combined light source of near-infrared (NIR), deep ultraviolet (Deep UV) and extreme ultraviolet light is irradiated together, the first metal particles or the first metal particles and the second metal particles, The substrate is optically bonded to facilitate densification of the structure, so that a digitizer flexible printed circuit board having excellent conductivity and durability can be manufactured.

However, as the energy of extreme ultraviolet light, infrared light and ultraviolet light increases, the optical coupling efficiency does not occur unconditionally. If the above-mentioned irradiation conditions are exceeded, the temperature of the substrate may become too high in a short period of time and damage to the substrate may occur. Can be performed only under irradiation conditions.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the scope and content of the present invention can not be construed to be limited or limited by the following Examples. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as set forth in the following claims. It is natural that it belongs to the claims.

≪ Example 1 >

0.8 g of PVP (MW 40,000, Sigma Aldrich Co, Ltd.), 9.5 g of ethylene glycol (99%, Sigma Aldrich Co. Ltd) and 0.3 g of Disperbyk 180 are mixed and dispersed for 2 hours using a sonicator. 5.0 g of copper nanoparticles (20-50 nm in diameter, Quantum Spehere Inc Co. Ltd) was added thereto, followed by dispersion using a sonicator and a stirrer, followed by re-dispersion using a mixed deaerator to prepare a mixed solution do. Some copper agglomerates clinging to the mixed solution are removed using a filter (pore size: 0.45 탆) and dispersed again with a mixed deaerator to prepare a copper solution. 3 ml of a silane coupling agent (KBE-603, Shin-Etsu silicones) was added to 1 g of the copper solution, 1 ml of γ-butyrolactone (Wako Pure Chemical Ind., Ltd) was added thereto to have an appropriate viscosity, 1 ml of ethoxyethanol (Wako Pure Chemical Ind., Ltd) was added, mixed with a mixed deaerator and a 3-roll mill to finally complete the copper nanoink. The copper nano ink was applied onto a polyimide substrate using a screen printer And printed in a mesh pattern which is an electrode form of a digitizer printed circuit board (FPCB). The pattern was dried in an oven at 60 ° C for 60 minutes before photo-sintering, and the digitizer printed circuit board (FPCB) was manufactured by irradiating extreme ultraviolet light using a xenon flash lamp. At this time, the irradiation conditions of the extreme ultraviolet-white light are 10 ms width of pulse, 1 pulse number, and 6 J / cm 2 pulse energy.

≪ Example 2 >

The copper nano ink prepared in Example 1 was screen printed on a PET substrate to print a mesh pattern as an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared light at 100 ° C After drying for 30 minutes, the digitizer printed circuit board (FPCB) is produced by irradiating extreme ultraviolet light using a xenon flash lamp.

At this time, the irradiation conditions of the extreme ultraviolet-white light are 10 ms pulse width, 20 pulse number, and 12 J / cm 2 pulse energy.

≪ Example 3 >

The copper nano ink prepared in Example 1 was screen-printed on a photo paper for printing on a digitized printed circuit board (FPCB) as a mesh pattern, and the pattern was printed After drying at 100 ° C for 30 minutes using infrared rays, a digitizer printed circuit board is manufactured by irradiating extreme ultraviolet light using a xenon flash lamp.

At this time, the irradiation conditions of the extreme ultraviolet-white light are 5 ms width of pulse, 3 pulse number, 5 ms pulse interval and 8 J / cm 2 pulse energy.

In Examples 1 to 3, a stepwise optical sintering technique was used in which the preliminary heating step (first pulse) and the densification step (second pulse) were divided into two steps, A pulsed light sintering technique may be used.

<Example 4>

The copper nano ink prepared in Example 1 was screen-printed on a photo paper for printing on a digitized printed circuit board (FPCB) as a mesh pattern, and the pattern was printed Dried at 100 ° C for 40 minutes using a hot plate, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation conditions of the extreme ultraviolet-white light are such that the pulse width is 5 ms, the number of pulses is 5, and the pulse energy is 10 J / cm 2.

&Lt; Example 5 >

Using the copper nano ink prepared in Example 1, screen printing was performed on a polyimide substrate to print in a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared light After drying at 100 ° C for 60 minutes, a digitizer printed circuit board is manufactured by irradiating extreme ultraviolet light using a xenon flash lamp.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 6 >

Using the copper nano ink prepared in Example 1, screen printing was performed on a polyimide substrate to print in a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared light After drying at 100 ° C for 60 minutes, a digitizer printed circuit board is manufactured by simultaneously irradiating ultraviolet white light and deep UV light using a xenon flash lamp.

At this time, the irradiation condition of the extreme-wave white light is such that the pulse width is 10 ms, the number of pulses is one, the pulse energy is 12.5 J / cm 2, and the intensity of the deep ultraviolet rays is 30 mW / cm 2.

&Lt; Example 7 >

Using the copper nano ink prepared in Example 1, screen printing was performed on a polyimide substrate to print a mesh pattern, which is an electrode form of a digitizer printed circuit board (FPCB), and a hot plate was used , Dried at 80 ° C for 60 minutes, irradiated with near infrared rays (NIR), and preheated, a digitizer printed circuit board is manufactured by simultaneously irradiating extreme ultraviolet light and deep ultraviolet light using a xenon flash lamp.

At this time, the irradiation condition of the extreme ultraviolet ray is 10 ms, the pulse width is 1, the pulse energy is 10 J / cm 2, and the intensity of the far ultraviolet ray is 100 mW / cm 2.

&Lt; Example 8 >

0.6 g of PVP, 2 ml of 2-butoxyethyl acetate and 9 g of diethylene glycol (DEG) were dispersed for 30 minutes using a sonicator. To this mixed solution, 3.0 g of copper nanoparticles (20-50 nm, Quantum sphere Inc. Co. Ltd), and a copper solution is prepared using a stirrer for 2 hours. 1.0 g of copper precursor (Cu (NO ₃ ) ₂ .5H ₂ O, 99.9%) as a copper precursor was dissolved in 20 ml of an ethanol solvent to prepare a copper precursor solution, which was added to the copper solution, , And then dispersed using a mixed deaerator to prepare a copper particle / precursor mixed solution. The copper particles / precursor mixture was filtered to remove some of the copper aggregate present in the mixed solution through a filter (pore size: 0.45 탆) and dispersed using a mixed deaerator to prepare a filtered copper particle / 72 mg of a silane coupling agent (KBE-603, Shin-Etsu silicones) was added to 1 g of the solution, 2 ml of butyl butyl ether was added to have an appropriate viscosity, and 1 ml of 2-ethoxyethanol Wako Pure Chemical Ind., Ltd) was added and dispersed using a mixed deaerator and a 3-roll mill to prepare a copper nanoink. The copper nano ink is printed 10 times on a PET substrate with an inkjet printer to form a mesh pattern of an electrode of a digitizer printed circuit board (FPCB) having a thickness of 1 mu m. The pattern was dried in an oven at 100 ° C for 90 minutes before photo-sintering, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 9 >

Copper nanoinks prepared in the same manner as in Example 8 except that copper precursor was made of copper nitrate (Cu (NO ₃ ) ₂ .5H ₂ O, 99.9%) and 2.5 ml of ethylene glycol butyl ether were added Copper particles / copper precursor).

The copper nano ink was screen printed on a photo paper for printing on a photographic paper to print a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared rays at 100 ° C Dried for 50 minutes, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation conditions of the extreme ultraviolet-white light are 10 ms in pulse width, 1 pulse number, and 10 J / cm 2 pulse energy.

&Lt; Example 10 >

(Copper particle / copper precursor) prepared in the same manner as in Example 8 except that the copper precursor is copper nitrate (Cu (NO ₃ ) ₂ .5H ₂ O, 99.9%).

(Spin coating) on polyimide using the copper nano ink to print a mesh pattern that is an electrode form of a digitizer printed circuit board (FPCB). Before the photo-sintering of the pattern, Minute, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation conditions of the extreme ultraviolet-white light are 10 ms in pulse width, 1 pulse number, and 10 J / cm 2 pulse energy.

&Lt; Example 11 >

5 g of 0.9 g PVP (MW 55,000, Sigma Aldrich Co, Ltd.) and 0.1 g of sodium cyanobenzene sulfate, and 2 ml of terpineol were added to ethylene glycol (DEG) And mixed to prepare a mixed solution. Thereafter, copper nanoparticles (20-50 nm, Quantum Sphere Inc Co., Ltd.) and copper nanowires (diameter 150 nm, length 5 μm, Skyspring Nanomaterials Inc Co., Ltd.) To prepare a total of 10.8 g. The mixture was added to the mixed solution, followed by dispersion using a mixed deaerator. The aggregate was filtered and redispersed using a ball mill and a 3-roll mill to prepare a copper nanoink ink.

The copper nano ink was printed on a PET substrate with an ink jet printer in the form of a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was dried using a hot plate at 100 DEG C for 60 minutes And digitally printed circuit boards are manufactured by irradiating extreme ultraviolet light using a xenon flash lamp.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 12 >

Copper nano ink prepared in the same manner as in Example 11 was used except that copper nano-particles and copper nano-wires were mixed at a ratio (weight%) of 99: 1 to produce copper nano ink.

Printed on a FR-4 substrate using the copper nano ink to print a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared rays at 100 DEG C for 90 minutes Dried, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 13 >

0.8 g of azobis and 8 g of ethylene glycol (DEG) were added to 1 ml of butyl ether and mixed with a sonicator for 30 minutes to prepare a mixed solution. Next, 13 g of copper nanoparticles (20-50 nm, Quantum Sphere Inc Co., Ltd.) and copper microparticles (2-8 μm, JoinM) were mixed at a ratio (weight%) of 50:50, The resulting solution is added to the mixed solution, dispersed with a stirrer and a sonicator, and further dispersed with a mixed deaerator to prepare a copper nano / micro solution. In the copper nano / micro solution, the agglomerates are removed by using a filter, and dispersed with a ball mill and a 3-roll mill to prepare a copper ink.

The copper ink was printed on a FR-4 substrate with an inkjet printer as a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was heated at 100 DEG C for 60 minutes Dried, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 14 >

The copper ink prepared in the same manner as in Example 13 was used except that the copper nanoparticles and the copper microparticles were mixed at a ratio (weight%) of 25:75 to prepare a copper ink.

Printed on a FR-4 substrate using the copper ink in a mesh pattern as an electrode of a digitizer printed circuit board (FPCB), and dried by infrared rays at 100 DEG C for 90 minutes before photo-sintering And digitally printed circuit boards are manufactured by irradiating extreme ultraviolet light using a xenon flash lamp.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 15 >

Copper nano ink prepared in the same manner as in Example 1 is used except that copper nanoparticles produced by the plasma heating method are used.

Printed on a FR-4 substrate using the copper nano ink to print a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared rays at 100 DEG C for 30 minutes Dried, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 16 >

Copper nano ink prepared in the same manner as in Example 1 was used except that copper nanoparticles prepared by an electric explosion method were used.

Printed on a FR-4 substrate using the copper nano ink to form a mesh pattern as an electrode of a digitizer printed circuit board (FPCB), and the pattern was irradiated with infrared rays at 100 DEG C for 80 minutes Dried, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 17 >

Copper nano ink prepared in the same manner as in Example 11 was used except that copper nano-particles and copper nano-wires were mixed at a ratio (weight%) of 99: 1 to produce copper nano ink.

The copper nano ink was printed on a polyimide substrate with an inkjet printer as a mesh pattern in the form of an electrode of a digitizer printed circuit board (FPCB), and the pattern was heated at 100 ° C for 60 minutes Dried, and irradiated with extreme ultraviolet light using a xenon flash lamp to produce a digitizer printed circuit board.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Example 18 >

A digitizer printed circuit board was manufactured in the same manner as in Example 17 except that copper nano particles and copper nano wires were mixed at a ratio (weight%) of 99: 2 to produce copper nano ink.

&Lt; Example 19 >

A digitizer printed circuit board was manufactured in the same manner as in Example 17 except that copper nano particles and copper nano wires were mixed at a ratio (weight%) of 99: 3 to produce copper nano ink.

&Lt; Comparative Example 1 &

Copper nano ink (copper particle / copper precursor) prepared in the same manner as in Example 8 was used, except that the copper precursor was copper sulfate (CuSO ₄ .5H ₂ O).

The copper nano ink was screen printed on polyimide to print a mesh pattern as an electrode of a digitizer printed circuit board (FPCB), and the pattern was dried at 100 ° C for 20 minutes using infrared rays before photo-sintering , And a digitizer printed circuit board is manufactured by irradiating extreme white light using a xenon flash lamp.

At this time, the irradiation condition of the extreme-wave white light is such that the width of the pulse is 10 ms, the number of pulses is 1, and the pulse energy is 12.5 J / cm 2.

&Lt; Comparative Example 2 &

A digitizer printed circuit board manufactured in the same manner as in Comparative Example 1 except that Cu (C ₃ H ₄ F ₃ O ₂ ) ₂ was used as a copper precursor to produce copper nano ink (copper particle / copper precursor) .

&Lt; Comparative Example 3 &

A digitizer printed circuit board manufactured in the same manner as in Comparative Example 1 except that the copper precursor was CuCl (copper (I) chloride, 9.995%) for producing copper nano ink (copper particle / copper precursor) .

7 is a graph showing measured sheet resistances when printing and applying conductive composite inks of various compositions to produce a digitizer flexible printed circuit board according to the present invention. In this case, Example 5, Example 13, Example 14, Example 11, Example 12, Example 8, and Comparative Examples 1, 2 and 3 are shown in order from the left side of the graph.

As shown in FIG. 7, it can be confirmed that the light sintering effect can be varied depending on the combination of the copper nanoparticles and the conductive composite ink containing one kind of copper precursor, copper nanowire and copper microparticles.

Particularly, in the case of the conductive composite ink using the copper precursor as the second metal particle, the case where Cu (NO ₃ ) ₂ 3H ₂ O was used was found to have the lowest sheet resistance, and when the remaining copper precursor was used, As shown in Fig.

Fig. 8 is a graph showing the results of the SEM (a) and the photo-sintering (b) of the conductive composite ink containing copper nanoparticles prepared by the plasma heating method according to the present invention (Example 15) before photo- FIG. 9 is a graph showing the results of photolithography (a) and light sintering (b) before photo-sintering the conductive composite ink (Example 16) comprising copper nanoparticles prepared by the electric wire explosion method according to the present invention, Fig.

The copper nanoparticles can be produced by electrical wire explosion, plasma heating, electrolysis, chemical synthesis, etc., and the surface properties and sintering effect of the copper nanoparticles are different from those of FIGS. 8 and 9.

In the case of the copper nano ink before sintering, it can be seen that copper nanoparticles are separated from each other, while after the sintering, the copper nanoparticles existing in the copper nano ink aggregate to form a connection loop.

10 is a graph showing the sheet resistance of each of the digitizer flexible printed circuit boards manufactured by printing conductive composite inks of various compositions according to the present invention on a substrate and photo-sintering the same on various conditions.

As shown in FIG. 10, the light sintering effect varies depending on the type of the substrate.

Specifically, the types of flexible substrates used in the experiments were PET, photographic paper, PI, and FR-4, which are polymer substrates for flexible low temperatures. After the conductive composite ink prepared in Example 1 was sintered under different drying and light sintering conditions, the sheet resistances of the fabricated digitizer flexible printed circuit boards were measured.

The substrate, conductive composite ink, drying and light sintering conditions for the digitizer flexible printed circuit board samples 1 through 10 described in the graph of FIG. 10 are shown in Table 1 below.

Sample number Board Drying conditions Light sintering condition One Photographic paper 60, hot plate Xenon lamp
5 ms, 1 time, 8 J / 2 100, hot plate Xenon lamp
5 ms, 5 times, 10 J / 3 60, Infrared Xenon lamp
10 ms, 1 time, 8 J / 4 60, Infrared Xenon lamp
10 ms, 1 time, 8 J / Far-ultraviolet
30 / 5 60, hot plate Xenon lamp
20 ms, 1 time, 6 J / 6 PET 60, hot plate Xenon lamp
10 ms, 1, 6 J / 7 100, infrared Xenon lamp
10 ms, 20 times, 12 J / 8 100, infrared Xenon lamp
10 ms, 1, 6 J / 9 100, infrared Xenon lamp
10 ms, 1, 6 J / Far-ultraviolet
30 / 10 FR-4 100, infrared Xenon lamp
10 ms, 1 time, 12.5 J /

It was confirmed that the digitizer flexible printed circuit board on which a pattern is formed on various substrates has remarkably low sheet resistance according to the drying and light sintering conditions and thus can be used industrially sufficiently.

That is, it can be confirmed that the improved method of manufacturing the digitizer flexible printed circuit board according to the present invention is much cheaper and simpler than the conventional process such as photolithography, and has remarkably excellent conductivity.

FIG. 11 is a photograph of the digitized flexible printed circuit board fabricated from Samples 1, 6, and 10 (a) and (b) before being photo-sintered in FIG.

As shown in FIG. 11, it can be seen that the pattern formed on the substrate or substrate is uniformly formed without cracking or breakage.

12 is a graph showing the results of X-ray diffraction analysis of the conductive composite ink according to the present invention before and after photo-sintering. As a result, the copper nanoparticles as the first metal particles and the polymer coated on the surface of the substrate, The reduction reaction occurred, and it was confirmed that it was reduced to pure copper and sintered. From the above results, it can be seen that sintering of the copper ink with higher conductivity is possible according to the light irradiation condition of the Xenon lamp.

Fig. 13 is a graph showing the results of measurement of the dielectric constant of the digitized flexible printed circuit board (manufactured by Fuji Photo Film Co., Ltd.) manufactured from Example 1 (), Example 17 (), Example 18 (The second copper particles are copper nanowires) after 1000 times of repeated outer bending tests.

Using the digitizer flexible printed circuit board manufactured from Example 1 and Examples 17 to 19 of the present invention, a repetitive outer bending test was conducted 1000 times, and the rate of change in resistance was measured.

As shown in FIG. 13, when the conductive composite ink is a combination of copper nano-particles and copper nano-wires, the resistance increase rate after repeating outward bending test increases as the content of copper nanowires increases in the digitizer flexible printed circuit board Respectively. It is believed that this is because the copper nanowires prevent the cracks from progressing further between the nanoparticles.

Claims (7)

Ⅰ) Polystyrene terephthalate (PBT), polysulfone, polyether, polyetherimide (PEI), acrylic resin, vinyl acetate resin (PVAC), butyl rubber resin, polyarylate (PAR) And FR-4;
(II) a conductive composite ink comprising first metal particles and at least one second metal particle selected from the group consisting of metal microparticles and metal nanowires on the upper or rear surface of the substrate is subjected to micro-contact printing, Printing with a printing method selected from among imprinting, gravure-offset printing, flexography printing, and spin coating to form a mesh pattern;
III) drying the pattern by one or more methods selected from infrared rays, hot plates and ovens; And
IV) Two or more kinds of light sources selected from extreme ultraviolet white light, near-infrared light of 0.1-3000 W / cm 2 intensity and far ultraviolet light of 1-5000 mW / cm 2 intensity are simultaneously irradiated to the dried pattern, or photo- The method comprising the steps of: providing a digitizer flexible printed circuit board; The method according to claim 1,
In the step (II), dispersing the conductive composite ink into at least one selected from an ultrasonic dispersing machine, a stirrer, a ball mill, and a 3 roll mill; And defoaming the digitizer flexible printed circuit board. The method according to claim 1,
Wherein the conductive composite ink comprises a first metal particle and at least one second metal particle selected from metal microparticles, metal nanowires, and a metal precursor,
The first metal particles and the second metal particles may be at least one selected from the group consisting of Cu, Au, Ag, Ni, Pt, Co, Fe, , Tungsten (W), molybdenum (Mo), manganese (Mn), chromium (Cr), zinc (Zn) and aluminum (Al). The method of claim 3,
The diameter of the first metal particles is 20-50 nm,
The diameter of the metal microparticles is 1-10 占 퐉,
Wherein the metal nanowires have a diameter of 10-200 nm and a length of 1-10 mu m. The method of claim 3,
If the second metal particles are metal microparticles,
The weight ratio of the first metal particles to the second metal particles is mixed in a ratio of 1 to 0.01 to 0.1,
If the second metal particles are metal nanowires,
Wherein the weight ratio of the first metal particles to the second metal particles is 1: 1 to 3: 1. The method according to claim 1,
Wherein the light sintering condition is a pulse width of 5-20 ms and an intensity of 1-50 J / cm 2 when the number of pulses of the xenon flash lamp is 1 to 20. The method according to claim 1,
Wherein the step (III) further comprises a preliminary light irradiation step for preheating or solvent drying.

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