KR20170107625A

KR20170107625A - Conductive Cu ink mixed with two different sizes Cu nanoparticles and preparation of Cu electrode using the same

Info

Publication number: KR20170107625A
Application number: KR1020160030991A
Authority: KR
Inventors: 김학성; 주성준; 유명현
Original assignee: 한양대학교 산학협력단
Priority date: 2016-03-15
Filing date: 2016-03-15
Publication date: 2017-09-26
Also published as: KR101911136B1

Abstract

A conductive copper ink mixed with copper nanoparticles of different sizes, and a method of manufacturing a copper electrode using the same. The method for producing a copper electrode according to the present invention includes the steps of preparing a conductive copper ink containing copper nanoparticles having different average particle sizes, a solvent and a polymeric binder resin, printing a conductive copper ink on a substrate to form a pattern And photo-sintering the pattern. According to the present invention, by providing a conductive copper ink composition in which copper nanoparticles of different sizes are mixed, a copper electrode having high electrical conductivity and adhesive strength can be produced. According to the present invention, by using a sintering method capable of sintering in a short time at room temperature and atmospheric pressure, a copper electrode can be mass-produced with a simpler process.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive copper ink containing copper nanoparticles of different sizes and a method of manufacturing the copper electrode using the copper nanoparticles.

The present invention relates to a conductive metal ink, and more particularly to a conductive copper ink composition.

Printed electronics is a technology for producing devices activated by sintering after printing on substrates using conductive metal nano ink. Compared with the complex processes using photolithography, these printing electronics have advantages such as simple process, low process and facility investment cost, environment friendly and mass production in large area. Therefore, they can be applied to flexible display, solar a variety of electronic devices requiring a printed circuit such as a radio frequency identification (RFID), wearable electronics, an organic light emitting device (OLED), and a digitizer sensor It is a promising technology that can be applied to products.

Gold, silver, and copper particles are used in the metal ink used in the printing electron. Various techniques are being studied in the sintering process, which is a heat treatment method in which printed metal ink is made conductive.

Conventionally, a heat sintering process is mainly used for sintering the conductive metal ink. The heat sintering process refers to a method of heating the printed metal ink in an inert gas atmosphere at a temperature of about 200 캜 to 350 캜 for several tens of minutes. Such a thermal sintering method takes a long time, which not only increases the overall process time but also damages the substrate due to a high temperature, so that it is difficult to produce an electronic pattern on a recent low-temperature polymer substrate or paper.

In addition, laser sintering method and microwave sintering method have been proposed as a new sintering method, but laser sintering method has a disadvantage that a narrow sintering range and sophisticated equipment are required. In addition, the microwave sintering method is disadvantageous in that it is unsuitable for practical application because of the disadvantage that the sintering thickness is thin and the size of the substrate is limited.

Therefore, in the electrode production, it is required to develop a sintering method capable of mass production in a simple and efficient manner, and a technique having high electrical conductivity and high adhesive strength, which are characteristics required before commercialization of the electrode is commercialized.

A problem to be solved by the present invention is to provide a conductive copper ink having high electrical conductivity and adhesive strength.

Another object of the present invention is to provide a sintering method capable of sintering in a short time at room temperature and normal pressure in the production of an electrode using metal ink, thereby enabling mass production.

According to an aspect of the present invention, there is provided a method of manufacturing a copper electrode using conductive copper ink mixed with copper nanoparticles of different sizes. The copper electrode manufacturing method includes the steps of: preparing a conductive copper ink containing copper nanoparticles having different average particle sizes, a solvent and a polymeric binder resin; printing the conductive copper ink on a substrate to form a pattern; And photo-sintering the pattern.

Wherein the copper nanoparticles include first copper nanoparticles, one or both of second copper nanoparticles and third copper nanoparticles are selectively mixed, and the first copper nanoparticles have an average particle size of 50 nm to 150 nm Wherein the second copper nanoparticles are copper nanoparticles having an average particle size of 1 nm to less than 50 nm and the third copper nanoparticles may be copper nanoparticles having an average particle size of more than 150 nm and 500 nm.

The first copper nanoparticles and the second copper nanoparticles may be mixed at a ratio of 1: 1 to 9: 1.

The first copper nanoparticles and the third copper nanoparticles may be mixed at a ratio of 1: 1 to 9: 1.

Wherein the first copper nanoparticles are copper nanoparticles having an average particle size of 80 nm to 120 nm, the second copper nanoparticles are copper nanoparticles having an average particle size of 30 nm to 50 nm, and the third copper nanoparticles have an average particle size of 200 nm- 300 nm. &Lt; / RTI >

In the copper nanoparticles, the first copper nanoparticles, the second copper nanoparticles, and the third copper nanoparticles may be mixed in a ratio of 1: 1: 1 to 5: 1: 1.

The conductive copper ink includes copper nanoparticles having a proportion of 30 to 89.9 parts by weight based on 100 parts by weight of the conductive copper ink, a solvent having a proportion of 10 to 60 parts by weight and a polymer binder resin having a proportion of 0.1 to 10 parts by weight can do.

The substrate may be subjected to plasma treatment, ozone gas treatment, or silane treatment before the printing is performed.

The drying may be carried out at a temperature of 80 ° C to below the boiling point of the solvent.

The light sintering may include a white light sintering method, and the light sintering may include a preliminary light irradiation step in which pre-heating or solvent drying is performed and a particle light sintering step in which particles are sintered.

The white light sintering method may be one in which near ultraviolet light, far ultraviolet light, or a combination thereof is irradiated.

In the white light sintering method, a xenon flash lamp is used, and the light intensity may be 3 to 60 J / cm ² when irradiated with light.

The number of pulses of the xenon flash lamp may be 2 to 40 times.

The light irradiation time of the xenon flash lamp may be 0.1 ms to 20 ms, and the pulse interval may be 0.1 ms to 30 ms.

According to another aspect of the present invention, there is provided a conductive copper ink comprising copper nanoparticles of different sizes. The conductive copper ink may include a first copper nanoparticle having an average particle size of 50 nm to 150 nm; At least one copper nanoparticle selected from the group consisting of second copper nanoparticles having an average particle size of less than 1 nm to less than 50 nm and third copper nanoparticles having an average particle size of more than 150 nm and less than 500 nm; menstruum; And a polymeric binder resin.

The first copper nanoparticles and the second copper nanoparticles may be mixed in a ratio of 1: 1 to 9: 1.

The first copper nanoparticles and the third copper nanoparticles may be mixed in a ratio of 1: 1 to 9: 1.

Copper nanoparticles having a proportion of 30 to 89.9 parts by weight based on 100 parts by weight of the conductive copper ink, a solvent having a proportion of 10 to 60 parts by weight and a polymer binder resin having a proportion of 0.1 to 10 parts by weight.

According to the present invention, by providing a conductive copper ink composition in which copper nanoparticles of different sizes are mixed, a copper electrode having high electrical conductivity and adhesive strength can be produced.

According to the present invention, by using a sintering method capable of sintering in a short time at room temperature and atmospheric pressure, a copper electrode can be mass-produced with a simpler process.

The technical effects of the present invention are not limited to those mentioned above, and other technical effects not mentioned can be clearly understood by those skilled in the art from the following description.

1 is a flowchart illustrating a method of manufacturing a copper electrode according to a first embodiment of the present invention.
2 is a schematic view showing a light sintering method according to a first embodiment of the present invention.
3A to 3C are photographs showing copper nanoparticles before and after performing the light sintering according to Production Example 1 of the present invention.
4A to 4D are SEM photographs showing the surface of the copper electrode according to Production Examples 1, 2, 3 and Comparative Example of the present invention.
5A and 5B are SEM images of a surface of a copper electrode according to Experimental Example 3 of the present invention.

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

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

In the present specification, the diameters of the copper nanoparticles mean the average diameter of the copper nanoparticles. As a measurement method, dynamic light scattering (DLS) can be used.

FIG. 1 is a flowchart showing a method of manufacturing a copper electrode according to a first embodiment of the present invention, and FIG. 2 is a schematic view showing a photo-sintering method of a first embodiment of the present invention.

Referring to FIG. 1, a conductive copper ink containing copper nanoparticles having different average particle sizes may be prepared. The copper nanoparticles may include the first copper nanoparticles, and may be selected from among the second copper nanoparticles and the third copper nanoparticles.

Specifically, the first copper nanoparticles may have an average particle size of 50 nm to 150 nm or less. The second copper nanoparticles may have an average particle size of less than 1 nm and less than 50 nm. The third copper nanoparticles may have an average particle size of more than 150 nm to 500 nm.

More specifically, the first copper nanoparticles may be copper nanoparticles having an average particle size of 80 nm to 120 nm. The second copper nanoparticles may be copper nanoparticles having an average particle size of 30 nm to 50 nm. The third copper nanoparticles may be copper nanoparticles having an average particle size of 200 nm to 300 nm.

For example, in the case of the copper nano ink mixed with the first copper nanoparticles and the second copper nanoparticles, they may be mixed at a ratio of 1: 1 to 9: 1. In addition, in the case of the copper nano ink mixed with the first copper nanoparticles and the third copper nano particles, they may be mixed at a ratio of 1: 1 to 9: 1. The copper nano ink mixed with the first copper nanoparticles, the second copper nanoparticles and the third copper nanoparticles may be mixed at a ratio of 1: 1: 1 to 5: 1: 1.

The copper nanoparticles may be contained in an amount of 30 to 89.9 parts by weight based on 100 parts by weight of the conductive copper ink. If the weight of the copper nanoparticles is less than 30 parts by weight, the viscosity of the ink becomes so low that it becomes difficult to maintain the patterned body after printing, and the ink may flow to the periphery. If the weight percentage of the copper nanoparticles is 89.9 or more, the viscosity of the ink becomes excessively high, so that the ink can not be discharged smoothly from the nozzles and smooth printing may not be performed.

Meanwhile, the conductive copper ink may include a solvent. The solvent may be an alcohol or a ketone-based material. For example, the solvent may be selected from the group consisting of ethylene glycol, diethylene glycol, triethylene glycol, poly-ethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, glycerine, iso-propyl alcohol, 2-methoxy ethanol, pentyl alcohol, butyl acrylate butyl acrylate (BA), athylacetate (EA), glycerol, cresol, methylethylketone (MEK), butyl carbitol acetate (BCA), butyl carbitol But are not limited to, texanol, terpineol, hexyl alcohol, butyl alcohol, octyl alcohol, form amide, methyl ethyl ketone, ethyl Alcohol (ethyl alcohol), methyl alcohol (me thyl alcohol, and acetone, may be used alone or in admixture of two or more.

The solvent may be contained in a proportion of 10 to 60 parts by weight based on 100 parts by weight of the conductive copper ink.

In addition, the conductive copper ink may include a polymeric binder resin. The polymeric binder resin may have a weight average molecular weight of 10,000 to 500,000. For example, the polymeric binder resin may be selected from the group consisting of polyvinylpyrrolidone, polyvinyl alcohol, polyvinyl chloride, cellulose resin, polyvinyl chloride resin, epoxy resin, phenol resin, rosin ester resin, polyester resin, , A polyvinyl alcohol-based resin, an acrylic resin, a vinyl acetate-acrylate copolymer resin, a butyral resin, an alkyd resin, and azobis.

The polymeric binder resin may be contained in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the conductive copper ink. If the weight ratio of the polymeric binder resin is less than 0.1, the oxide film on the surface of the copper nanoparticles formed in the air does not smoothly occur when the conductive copper ink is printed, and sintering may not be performed well. When the weight ratio of the polymeric binder resin is 10 or more, the polymeric binder resin may interfere with the sintering of the copper nanoparticles.

Thereby, the conductive copper ink can be produced (S100). On the other hand, in order to smoothly disperse the copper nanoparticles, the solvent and the polymer binder resin in the conductive copper ink, the dispersion may be performed by one or a combination of two or more materials selected from an ultrasonic disperser, a stirrer, a ball mill and a 3 ball mill .

The conductive copper ink may then be printed on the substrate. The substrate may be paper, glass, polymer, or ceramic.

For example, the polymer may be selected from the group consisting of polybutylene terephthalate, polyethylene terephthalate, polysulfone, polyether, polyetherimide, polyethylene naphthalate, acrylic resin, heat resistant epoxy, BT epoxy / glass fiber, , Butyl rubber resin, polyarylate, polyimide, silicone, ferrite or FR-4.

Before printing the conductive copper ink, the surface of the substrate may be treated with oxygen plasma or ozone gas. The surface treatment method of the substrate may be a method in which the substrate is placed in a chamber having an oxygen plasma or ozone gas or a surface treatment is performed for a predetermined time by placing the substrate in the lower part of the apparatus capable of generating the oxygen plasma or ozone gas. At this time, if the surface of the substrate is treated with plasma, a hydroxyl group may be generated on the surface. The hydroxyl group thus formed is bonded to a functional group such as methoxy, ethoxy or acetoxy contained in a solvent in the conductive copper ink, for example, 2-methoxyethanol, ethyl acetate, terpineol, The adhesion between the conductive copper ink can be increased.

Examples of the method of printing the conductive copper ink on the substrate include a screen printing method, an inkjet printing method, a micro-contact printing method, an imprinting method, a gravure printing method, Gravure-offset printing, flexography printing, and spin coating. [0043] The present invention can be carried out in a variety of ways. At this time, the printing speed may be 30 to 200 mm / s. If the printing speed is slower or faster than the above range, the ink pattern may not be printed clearly.

The printed conductive ink may then undergo a drying process. The drying process necessarily includes infrared rays, and may be performed by selecting at least one of a hot air fan, a heat chamber, and a hot plate. At this time, it is preferable that the drying temperature is maintained at 80 ° C to less than the boiling point of the solvent within 1 hour in order not to damage the polymer substrate. If the drying temperature is lower than 80 캜, the solvent may remain in the dried ink during the drying process, thereby damaging the pattern during sintering. If the drying temperature is higher than the boiling point of the solvent or higher than the boiling point of the solvent, the solvent may be boiled during drying.

That is, by performing the drying process at the temperature within the above range, formation of micropores after sintering is prevented, so that a copper electrode having high electrical conductivity and high adhesion after sintering can be obtained (S200).

Next, photo-sintering may be performed using the light energy on the printed circuit board formed (S300)

Referring to FIG. 2, the light energy used in the light sintering may be white light. The light sintering using the white light may be performed by near infrared, deep ultraviolet, or a combination thereof. For example, the white light may be an IPL (Intense Pulsed Light) emitted from a xenon lamp. The pulse width of the extreme ultraviolet light may be 500 nm to 950 nm.

At this time, when the xenon lamp is irradiated with light, the intensity of light may be 3 to 60 J / cm ² . The light irradiation time of the xenon lamp may be 0.1 ms to 20 ms. The pulse interval of the xenon lamp may be 0.1 ms to 30 ms.

The pulse number may be 2 to 40 times. If a single pulse is used to irradiate all the light energy in a single pulse at the time of light irradiation, suddenly a large amount of energy is suddenly applied, and a large amount of pores are generated due to the evaporation of the polymer binder, resulting in a high resistance. Accordingly, in order to prevent such a problem, the conductive copper ink can be sintered using a multi-purse method in which light energy is divided into several pulses.

That is, when the white light is irradiated, the multi-pulse method prevents sudden rise in temperature, thereby preventing evaporation and reduction of the binder. In addition, the multi-pulse method prevents the copper particles of small size from melting first, Lt; / RTI > can be achieved. Thereby, the effect of improving the electrical conductivity and the bonding strength of the copper electrode after sintering can be exhibited.

The details of the multi-pulse in the above-described conditions for performing the light sintering will be further described through Experimental Example 3 to be described later.

Meanwhile, preliminary light irradiation for preheating or solvent drying for increasing the sintering efficiency may be performed before the light sintering is performed. As a result, the structure of the copper electrode formed after the photo-sintering can be made more compact.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms.

Hereinafter, comparative examples are copper ink using one kind of copper nanoparticles and copper electrode manufacturing method including the same. Production Examples 1 to 4 are copper ink using two or three types of copper nanoparticles and copper electrode manufacturing method .

Manufacture of Copper Electrode using Class 1 Particulate Copper Ink

A solvent in which diethylene glycol (DEG) and diethylene glycol butyl ether (DGBE) were mixed at a ratio of 1: 1 was prepared in an amount of 17 parts by weight based on 100 parts by weight of the total ink.

Next, 3 parts by weight of a polymeric binder resin polyvinylpyrrolidone (PVP) (MW 55,000) was added to the solvent in an amount of 3 parts by weight based on 100 parts by weight of the total ink, and the mixture was dispersed using a sonicator.

Subsequently, copper nanoparticles having an average particle size of 100 nm (Tekna) were added in an amount of 80 parts by weight based on 100 parts by weight of the total ink, followed by dispersion using a 3-roll mill to prepare a conductive copper ink.

The above-prepared conductive copper ink was printed on a polyimide substrate (PI, thickness: 50 mu m) in the form of an electrode at a speed of 50 mm / s using a screen printer. The pattern was dried using infrared rays at a temperature of 100 占 폚 to complete an electrode pattern, and then white light was irradiated onto the dried pattern. In this case, the number of pulses is 5, the irradiation time per unit is 1 ms, the pulse gap is 4 ms, and the irradiated light energy is 6 J / cm ² .

&Lt; Preparation Example 1 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

Except that copper nanoparticles each having an average particle size of 100 nm (Tekna) and 40 nm (XuZhou Corp.) were mixed in a ratio of 3: 1 were used to prepare a conductive copper ink Respectively.

The method of pattern printing the conductive copper ink was also performed in the same manner as the comparative example.

&Lt; Preparation Example 2 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

Except that copper nanoparticles each having an average particle size of 100 nm (Tekna) and 40 nm (XuZhou Corp.) were mixed in a ratio of 1: 1, respectively, to prepare a conductive copper ink Respectively.

&Lt; Preparation Example 3 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

Except that copper nanoparticles each having an average particle size of 100 nm (Tekna) and 40 nm (XuZhou Corp.) were mixed in a ratio of 1: 3, respectively, to prepare a conductive copper ink Respectively.

&Lt; Preparation Example 4 &

Manufacture of Copper Electrode Using Three-Particle Mixed Copper Ink

Conductive copper ink was prepared in the same manner as in Comparative Example except that copper nanoparticles were used in which copper nanoparticles having an average particle size of 100 nm, 40 nm, and 250 nm, respectively, were mixed in a ratio of 3: 1: 1.

FIGS. 3A to 3C are photographs showing copper nanoparticles before and after performing light sintering according to Production Example 1 of the present invention. FIG.

Specifically, FIG. 3A is a photograph showing copper nanoparticles each having a size of 40 nm and 100 nm before the photo-sintering of the conductive copper ink of Production Example 1 described above was performed. FIGS. 3B and 3C show the copper nanoparticles after multistage sintering is performed on the conductive copper ink. FIG. 3B shows a case where 40 nm of copper nanoparticles are sintered firstly, and FIG. 3C shows that 100 nm of copper nanoparticles are sintered .

That is, the multi-step sintering of the conductive copper ink in which the copper particles of a small size are first melted and the large copper particles are sequentially melted and sintered is performed, thereby preventing sudden rise in temperature when the conductive copper ink is irradiated with white light, Can be prevented.

In addition, it is possible to improve the electrical conductivity of the copper film and the adhesion strength between the copper film after sintering through the multistage sintering. In addition, in the case of glass and silicon wafer, since the thermal conductivity of the substrate is high, high energy is required in sintering and it is difficult to realize a single pulse, so that multi-pulse is applied Lt; / RTI >

Comparison of resistance change of conductive copper ink according to average particle size and mixing ratio of copper nanoparticles

Conductive copper ink (Preparation Examples 1, 2, 3 and 4) prepared by mixing copper nanoparticles with two kinds of particles and three kinds of particles, respectively, and one kind of particle copper ink (Comparative Example) as a control group were sintered The resistance change was measured.

The results of the experiment are shown in Table 1 below.

Ink type Nano particle mixing ratio Light irradiation condition Board Resistance after sintering Class 1 copper ink
(Comparative Example) 100 nm 100 wt% 5 pulse
1ms On-time
4ms Off-time
Energy: 6 J / cm ² PI film 0.176 Ohm / sq Binary particle mixed copper ink
(Production Examples 1, 2, 3) 100 nm 75 wt%
40 nm 25 wt% 5 pulse
1ms On-time
4ms Off-time
Energy: 6 J / cm ² PI film 0.025 Ohm / sq 100 nm 50 wt%
40 nm 50 wt% 5 pulse,
1ms On-time
4ms Off-time
Energy: 6 J / cm ² PI film 0.027 Ohm / sq 100 nm 25 wt%
40 nm 75 wt% 5 pulse,
1ms On-time
4ms Off-time
Energy: 6 J / cm ² PI film 0.053 Ohm / sq Tri-particle mixed copper ink
(Production Example 4) 100 nm 60 wt%
40 nm 20 wt%
250 nm 20 wt% 5 pulse,
1ms On-time
4ms Off-time
Energy: 6 J / cm ² PI film 0.023 Ohm / sq

Referring to Table 1 above, it can be seen that, when a copper ink mixed with two or three kinds of copper nanoparticles is used rather than a copper ink containing one kind of copper nanoparticles, an electrode having high electrical conductivity is produced after sintering .

As a result of comparing copper inks (Preparation Examples 1, 2 and 3) in which two types of copper nanoparticles were mixed, copper nanoparticles of 100 nm and 40 nm were 75 wt% and 25 wt%, that is, 3: 1 (Production Example 3) is higher than that of Production Examples 1 and 2.

Further, even in the case of the copper ink (Preparation Example 4) in which copper ink mixed with 3 types of copper nanoparticles and copper nanoparticles of 100 nm, 40 nm and 250 nm were mixed at a ratio of 3: 1: 1, respectively, Able to know.

4A to 4D are scanning electron micrographs showing the morphology of the surface of the copper electrode according to Production Examples 1, 2, 3 and Comparative Example of the present invention.

4A to 4D, it can be seen that, in comparison with the comparative example, in the case of the copper electrodes using the copper ink in Production Examples 1, 2 and 3, that is, the copper nanoparticles mixed with two kinds of copper nanoparticles, . That is, in the case of the copper ink mixed with two kinds of copper nanoparticles, small nanoparticles are inserted between the large-sized nanoparticles, so that the pores are reduced during printing, and the necking is improved even when sintering is performed, High-quality copper electrodes can be manufactured. This densification of the copper electrode can exert the effect of increasing the electrical conductivity, oxidation resistance and adhesion when the copper electrode is actually used.

Production Examples 5 to 12 below describe a conductive copper ink composition prepared by varying the composition ratios of copper nanoparticles, a solvent and a binder resin, which are copper ink compositions, and a method of manufacturing a copper electrode containing the same.

&Lt; Production Example 5 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A solvent in which diethylene glycol (DEG) and diethylene glycol butyl ether (DGBE) were mixed at a ratio of 1: 1 was prepared in an amount of 17 parts by weight based on 100 parts by weight of the total ink. Then, 3 parts by weight of a polymeric binder resin polyvinylpyrrolidone (PVP) (MW 55,000) was dissolved in the solvent in an amount of 3 parts by weight based on 100 parts by weight of the total ink, and the mixture was dispersed using a sonicator.

Subsequently, copper nanoparticles in which copper nanoparticles having an average particle size of 100 nm and 40 nm respectively were mixed in a ratio of 3: 1 were added in an amount of 80 parts by weight based on 100 parts by weight of the total ink, and the mixture was dispersed using a 3 roll mill, Ink.

The above-prepared conductive copper ink was printed on a polyimide substrate (PI, thickness: 50 mu m) in the form of an electrode at a speed of 50 mm / s using a screen printer. The pattern was dried using infrared rays at a temperature of 100 占 폚 to complete an electrode pattern, and then white light was irradiated onto the dried pattern. In this case, the number of pulses is 5, the irradiation time per unit is 2 ms, the pulse gap is 5 ms, and the irradiated light energy is 10 J / cm ² .

&Lt; Production Example 6 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5, except that 6 wt% of the polymeric binder resin, 80 wt% of the copper nanoparticles, and 14 wt% of the solvent were added to 100 wt% of the total ink.

Then, pattern printing was performed in the same manner as in Production Example 5 using the conductive copper ink prepared above.

&Lt; Production Example 7 >

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5, except that 3 wt% of the polymeric binder resin, 50 wt% of the copper nanoparticles and 47 wt% of the solvent were mixed with 100 wt% of the total ink.

&Lt; Production Example 8 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5, except that 3 wt% of the polymeric binder resin, 70 wt% of the copper nanoparticles, and 27 wt% of the solvent were mixed with 100 wt% of the total ink.

&Lt; Production Example 9 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5, except that 0 wt% of the polymeric binder resin, 80 wt% of the copper nanoparticles, and 20 wt% of the solvent were added to 100 wt% of the total ink.

&Lt; Production Example 10 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5, except that 12 wt% of the polymeric binder resin, 80 wt% of the copper nanoparticles, and 14 wt% of the solvent were added to 100 wt% of the total ink.

&Lt; Production Example 11 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5, except that 6 wt% of the polymeric binder resin, 25 wt% of the copper nanoparticles and 69 wt% of the solvent were added to 100 wt% of the total ink.

&Lt; Production Example 12 &

Manufacture of Copper Electrode Using 2-Particle Mixed Copper Ink

A copper ink was prepared in the same manner as in Production Example 5 except that 1 wt% of the polymeric binder resin, 95 wt% of the copper nanoparticles, and 4 wt% of the solvent were added to 100 wt% of the total ink.

Mixing of conductive copper ink compositions Comparison of resistance change to ratio

Resistance change was measured after sintering the conductive copper ink (Production Examples 5 to 12) prepared by varying the composition ratio of polymer binder resin, solvent, and copper nanoparticles in conductive copper ink mixed with two kinds of copper nanoparticles. The results of the experiment are shown in Table 2 below.

Ink type Ink composition Light irradiation condition Board Resistance after sintering Production Example 5 Polymeric binder 3 wt%
Copper nanoparticles 80 wt%
Solvent 17 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film
0.0252 Ohm / sq

Production Example 6 Polymeric binder 6 wt%
Copper nanoparticles 80 wt%
Solvent 14 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm2 PI film
0.0354 Ohm / sq

Production Example 7 Polymeric binder 3 wt%
Copper nanoparticles 50 wt%
Solvent 47 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film 0.0443 Ohm / sq
Production Example 8 Polymeric binder 3 wt%
Copper nanoparticles 70 wt%
Solvent 27 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film 0.0283 Ohm / sq
Production Example 9 Polymeric binder 0 wt%
Copper nanoparticles 80 wt%
Solvent 50 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film X
(Peeling in sintering)
Production Example 10 Polymer binder 12 wt%
Copper nanoparticles 80 wt%
Solvent 14 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film 1.1512 Ohm / sq
(Sintering does not occur smoothly)
Production Example 11 Polymeric binder 6 wt%
Copper nanoparticles 25 wt%
Solvent 69 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film 1.3154 Ohm / sq
(Blurring of pattern)
Production Example 12 Polymeric binder 1 wt%
Copper nanoparticles 95 wt%
Solvent 4 wt% 5 pulse
On-time 2 ms
Off-time 5 ms
Energy: 10 J / cm ² PI film X
(Poor discharge during printing)

Referring to Table 2, it can be seen that the print quality and sintering characteristics of the copper ink are established as the composition ratios of the copper nanoparticles, the solvent and the polymer binder are changed. That is, in the conductive copper ink, the conductive copper nanoparticles are contained in an amount of 30 to 89.9 parts by weight based on 100 parts by weight of the conductive copper ink, 10 to 60 parts by weight of the solvent, and 0.1 to 10 parts by weight of the polymeric binder resin It can be seen that printing and sintering are carried out.

For example, the print quality and electrical conductivity of the copper ink mixed at a ratio of 3 wt% of the polymer binder, 80 wt% of the copper nanoparticles and 17 wt% of the solvent are high. If any one of the compositions of the conductive copper ink is not included in the above-mentioned range, it can be confirmed that printing and sintering are not properly performed.

The type of substrate and Light irradiation Comparison of the resistance change of conductive copper ink according to the condition

Conductive copper ink was prepared according to the preparation method of Preparation Example 3, except that copper nanoparticles having a size of 100 nm and a size of 40 nm were mixed at a ratio of 50 wt% and 50 wt%, respectively.

Next, the conductive copper ink was printed on a polyethylene terephthalate ( PET ) substrate, a polyimide (PI film) substrate, a glass substrate, and a silicon substrate, respectively, in an electrode form at a speed of 50 mm / s using a screen printer Respectively. The pattern was dried using infrared rays at a temperature of 100 占 폚 to complete an electrode pattern, and then white light was irradiated onto the dried pattern.

The conditions of light irradiation at this time were set differently according to the type of the substrate as shown in Table 3 below. The results of the comparison of the resistance variation of the conductive copper ink according to the type of substrate and the light irradiation conditions are shown in Table 3 below.

Ink type Type of substrate Light irradiation condition Resistance after sintering Heterogeneous mixed copper ink
100 nm 50 wt%
40 nm 50 wt% PET film 1 pulse, 12 ms On-time, 6 J / cm ² 0.135 Ohm / sq 2 pulse, 2 ms On-time
10 ms Off-time, 4 J / cm ² 0.032 Ohm / sq 4 pulse, 2 ms On-time
10 ms Off-time, 5 J / cm ² 0.030 Ohm / sq 6 pulse, 2 ms On-time
10 ms Off-time, 6 J / cm ² 0.028 Ohm / sq PI film 4 pulse, 1 ms On-time
5 ms Off-time, 7 J / cm ² 0.029 Ohm / sq 5 pulse, 1 ms On-time
5 ms Off-time, 9 J / cm ² 0.030 Ohm / sq 10 pulse, 1 ms On-time
10 ms Off-time, 11 J / cm ² 0.026 Ohm / sq Glass film 5 pulse, 3 ms On-time
4 ms Off-time, 15 J / cm ² 0.035 Ohm / sq 15 pulse, 1 ms On-time
10 ms Off-time, 25 J / cm ² 0.043 Ohm / sq 20 pulse, 1 ms On-time
15 ms Off-time, 30 J / cm ² 0.041 Ohm / sq Silicon wafer 30 pulse, 2 ms On-time
30 ms Off-time, 40 J / cm ² 0.020 Ohm / sq 30 pulse, 1 ms On-time
30 ms Off-time, 50 J / cm ² 0.022 Ohm / sq 40 pulse, 1 ms On-time
30 ms Off-time, 55 J / cm ² 0.021 Ohm / sq

Referring to Table 3, the optimal conditions for the light sintering conditions described above may vary depending on the type of the conductive copper ink and the type of the substrate. For example, it can be seen that when a single pulse is applied to irradiate all the light energy with a pulse, a high resistance is measured as shown in the case of the polyethylene terephthalate ( PET ) substrate of Table 3 have. That is, when the conductive copper ink is sintered with a single pulse, a large amount of energy is suddenly applied, and the pores are formed due to the rapid evaporation of the polymer binder, resulting in a high resistance.

5A and 5B are SEM images of a surface of a copper electrode according to Experimental Example 3 of the present invention.

Referring to FIG. 5A, when the conductive copper ink is sintered in a single pulse, a lot of voids are generated due to the abrupt evaporation of the polymeric binder due to a sudden application of a large amount of energy.

On the other hand, referring to FIG. 5B, when the conductive copper ink is sintered with a multi pulse in which light energy is divided into a plurality of pulses, the conductive copper ink is sintered in a single pulse, It can be confirmed that the pores of the electrode are smaller.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

Claims

Preparing a conductive copper ink containing copper nanoparticles, a solvent and a polymeric binder resin having different average particle sizes;
Printing the conductive copper ink on a substrate to form a pattern; And
And photo-sintering the pattern.

The method according to claim 1,
The copper nanoparticles include first copper nanoparticles, and one or two of the second copper nanoparticles and the third copper nanoparticles are selectively mixed,
Wherein the first copper nanoparticles are copper nanoparticles having an average particle size of 50 nm to 150 nm and the second copper nanoparticles are copper nanoparticles having an average particle size of 1 nm to less than 50 nm and the third copper nanoparticles have an average particle size of more than 150 nm To 500 nm. &Lt; / RTI >

3. The method of claim 2,
Wherein the first copper nanoparticles and the second copper nanoparticles are mixed at a ratio of 1: 1 to 9: 1.

3. The method of claim 2,
Wherein the first copper nanoparticles and the third copper nanoparticles are mixed at a ratio of 1: 1 to 9: 1.

3. The method of claim 2,
Wherein the first copper nanoparticles are copper nanoparticles having an average particle size of 80 nm to 120 nm, the second copper nanoparticles are copper nanoparticles having an average particle size of 30 nm to 50 nm, and the third copper nanoparticles have an average particle size of 200 nm- Wherein the copper nanoparticles are copper nanoparticles having a thickness of 300 nm.

3. The method of claim 2,
Wherein the first copper nanoparticles, the second copper nanoparticles and the third copper nanoparticles are mixed in a ratio of 1: 1: 1 to 5: 1: 1 in the copper nanoparticles. .

The method according to claim 1,
The conductive copper ink includes copper nanoparticles having a proportion of 30 to 89.9 parts by weight based on 100 parts by weight of the conductive copper ink, a solvent having a proportion of 10 to 60 parts by weight and a polymer binder resin having a proportion of 0.1 to 10 parts by weight Gt; copper electrode < / RTI >

The method according to claim 1,
Wherein the substrate is subjected to plasma treatment, ozone gas treatment, or silane treatment before the printing is performed.

The method according to claim 1,
Wherein the drying is performed at a temperature of from 80 캜 to less than the boiling point of the solvent.

The method according to claim 1,
Wherein the light sintering includes a white light sintering method,
Wherein the light sintering step comprises a preliminary light irradiation step in which pre-heating or solvent drying is performed, and a particle light sintering step in which particles are sintered.

11. The method of claim 10,
Wherein the white light sintering method is conducted together with near infrared rays, deep ultraviolet rays, or a combination thereof.

12. The method of claim 11,
Wherein the white light sintering method uses a xenon flash lamp and the intensity of light is 3 to 60 J / cm ² when irradiated with light.

13. The method of claim 12,
Wherein the number of pulses of the xenon flash lamp is 2 to 40 times.

14. The method of claim 13,
Wherein the light irradiation time of the xenon flash lamp is 0.1 ms to 20 ms and the pulse interval is 0.1 ms to 30 ms.

Primary copper nanoparticles having an average particle size of 50 nm to 150 nm; At least one copper nanoparticle selected from the group consisting of second copper nanoparticles having an average particle size of less than 1 nm to less than 50 nm and third copper nanoparticles having an average particle size of more than 150 nm and less than 500 nm; menstruum; And a polymeric binder resin.

16. The method of claim 15,
Wherein the first copper nanoparticles and the second copper nanoparticles are mixed in a ratio of 1: 1 to 9: 1.

16. The method of claim 15,
Wherein the first copper nanoparticles and the third copper nanoparticles are mixed in a ratio of 1: 1 to 9: 1.

16. The method of claim 15,
Wherein the first copper nanoparticles are copper nanoparticles having an average particle size of 80 nm to 120 nm, the second copper nanoparticles are copper nanoparticles having an average particle size of 30 nm to 50 nm, and the third copper nanoparticles have an average particle size of 200 nm- Conductive copper ink, which is copper nanoparticles having a diameter of 300 nm.

16. The method of claim 15,
Wherein the copper nanoparticles, the second copper nanoparticles, and the third copper nanoparticles are mixed in a ratio of 1: 1: 1 to 5: 1: 1 in the copper nanoparticles.

16. The method of claim 15,
Wherein the conductive copper ink contains copper nanoparticles having a proportion of 30 to 89.9 parts by weight based on 100 parts by weight of the conductive copper ink, a solvent having a ratio of 10 to 60 parts by weight, and a polymeric binder resin having a proportion of 0.1 to 10 parts by weight, .