KR20110112560A - Electro-conducitve copper powder coated with anti-oxidizng material and method for preparing the same - Google Patents

Abstract

The present invention provides a conductive copper powder coated on the surface with an oxidation resistant material, wherein the oxidation resistant material has a higher oxidation resistance than the copper powder and a lower firing temperature, a method for producing the conductive copper powder, and the conductive copper powder It provides a conductive paste comprising a.
According to the present invention, by coating the surface of the conductive copper powder with an oxidation resistant material such as glass or silver (Ag), the oxidation of the copper powder can be prevented, and when used in an electrode paste, excellent electrical conduction characteristics can be exhibited. The firing temperature of the can be lowered to facilitate the formation of the electrode.

Description

ELECTRO-CONDUCITVE COPPER POWDER COATED WITH ANTI-OXIDIZNG MATERIAL AND METHOD FOR PREPARING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper powder used as a conductive material for electrode pastes and the like, and more particularly, to a conductive copper powder having a superior conductive property without being oxidized by being coated with an oxidation resistant material and a method of manufacturing the same.

Electroconductive pastes for forming electrodes used in electronic parts such as printed circuit boards are generally manufactured by mixing conductive metal powders, organic binders, glass frits, and other additives, and using screen printing, offset printing, photolithography, and the like. After printing in the form of a pattern, it is formed into an electrode through a firing process. At this time, silver (Ag) powder, which has excellent electrical conductivity and good oxidation characteristics, was mainly used as the conductive metal powder. However, due to the high unit cost, it is a cause of increase in cost, and short circuit due to migration of electrons occurs even after electrode formation. Problems have been pointed out. Therefore, there have been attempts to replace the conductive metal powder of the electrode paste with aluminum, copper, nickel, or the like instead of silver (Ag) powder.

In the case of copper (Cu) powder, the unit price is lower than that of silver (Ag) powder and exhibits a similar level of electrical conductivity as silver powder, which has advantages as an electrode forming material. have.

Metal powders, which are mainly used as electrode materials, are synthesized by a gas phase method or a liquid phase method, and thus most have a spherical shape. Currently, glass frit powder synthesis techniques use traditional melting methods. Under the basic process, the molten raw material was quenched in the form of a flake and then subjected to various milling and classification processes to synthesize glass frit powder having a desired particle size. In the above technique, several steps of milling and classification processes are essential, which has disadvantages such as poor performance of the glass frit powder, a large number of unit processes, and a yield reduction for obtaining a powder having a desired particle size. Although many disadvantages have been overcome at present, there are still disadvantages and they have to be taken care of, and in order to overcome the problem of dispersibility, much efforts have been made in paste manufacturing technology.

Copper powders are available in electrode sizes ranging from tens of nanometers to several microns. On the other hand, the conventional method is difficult to nano-size the glass powder. Therefore, different size and shape characteristics of silver and glass powders make it difficult to prepare a stable paste.

The inventors of the present invention can prevent oxidation of the copper powder when the surface of the copper powder is coated with an oxidation resistant material such as glass or silver (Ag), and thus, when used as a conductive powder for electrode paste, it is possible to exhibit excellent electrical conductivity. Of course, it has been found that the oxidation temperature of glass, silver, and the like coated on the surface may lower the firing temperature of the electrode to facilitate the formation of the electrode. In particular, when using a glass material as the oxidation-resistant material to coat the surface of the copper powder, it was found that the non-uniformity and paste instability that may occur in the process of pasting and mixing the conventional copper powder and glass frit has been found.

The present invention is based on the above.

The present invention comprises the steps of: a) preparing a precursor solution by dissolving a precursor of copper and a precursor of an oxidation resistant material in a solvent; b) dropleting the precursor solution through a spray device; c) introducing the droplets into a heating device; d) providing a method for producing a conductive copper powder coated with an oxidizing material, the surface comprising the step of obtaining the powder passed through the heating apparatus.

In addition, the present invention provides a conductive copper powder, the surface of which is coated with an oxidation resistant material, the oxidation resistant material is characterized by greater oxidation resistance than copper powder.

And this invention provides the electrically conductive paste containing the electroconductive copper powder as described above.

In addition, the present invention comprises the steps of applying the conductive paste described above to all or part of the substrate; And it provides a method for producing an electrode comprising the step of forming the electrode by firing the applied substrate in the range 500 ~ 1000 ℃.

And this invention provides the electrode manufactured by the manufacturing method of the electrode as described above.

According to the present invention, by coating the surface of the conductive copper powder with an oxidation resistant material such as glass or silver (Ag), the oxidation of the copper powder can be prevented, and when used in an electrode paste, excellent electrical conduction characteristics can be exhibited. The firing temperature of the can be lowered to facilitate the formation of the electrode. In particular, when the electrode is manufactured using the conductive copper powder paste of the present invention, since the conductive copper powder and other components are very uniformly mixed, a very dense electrode can be obtained, and the adhesion property with the substrate is also very excellent.

1 is a schematic diagram of a copper powder production apparatus using spray pyrolysis.
2 is a flowchart of a manufacturing process of Example 1;
3 is a schematic diagram showing a process of synthesizing a copper powder by spray pyrolysis.
FIG. 4 is a schematic diagram showing a process of synthesizing a copper powder whose surface is coated with an oxidation resistant material by spray pyrolysis.
5 is a TGA (Thermal Gravimetry Analysis) graph of the conductive copper powder prepared in Example 1 and Comparative Example 1.
6 is a differential scanning calorimetry (DSC) graph of the conductive copper powders prepared in Example 1 and Comparative Example 1. FIG.
7 is a TGA and DSC graph of conductive copper powder coated with 3 parts by weight of silver (Ag) prepared in Example 2. FIG.
8 is a transmission electron microscope (TEM) photograph of the conductive copper powder prepared in Example 1. FIG.
9 is a TEM photograph of a conductive copper powder coated with 10 parts by weight of glass prepared in Example 1. FIG.
FIG. 10 is a TEM photograph and a cross-sectional component profile graph by EDS of a conductive copper powder coated with 15 parts by weight of silver (Ag) prepared in Example 2. FIG.
FIG. 11 is a SEM (Scanning Electron Microscope) photograph and sheet resistance measurement of a conductive film according to firing temperature when the conductive film is manufactured as in Example 3 using the conductive copper powder prepared in Example 1 The result graph.
12 is an XRD (X-Ray Diffraction) analysis result according to the glass content of the conductive copper powder prepared in Example 1. FIG.
FIG. 13 is a SEM (Scanning Electron Microscope) photograph and sheet resistance measurement of a conductive film according to firing temperature when the conductive film is prepared as in Example 3 using the conductive copper powder prepared in Example 2 The result graph.
14 is an XRD (X-Ray Diffraction) analysis result according to the content of silver (Ag) for the conductive copper powder prepared in Example 2. FIG.
15 is a SEM photograph according to the content of glass for the conductive copper powder prepared in Example 1. FIG.
16 is a SEM photograph according to the content of silver (Ag) for the conductive copper powder prepared in Example 2. FIG.

In the present specification, the oxidation resistance means a property that oxidation does not occur when contacted with oxygen, and the high oxidation resistance means that the temperature at which oxidation occurs is high even when oxidation occurs by heating to a high temperature.

In the present specification, the firing means applying the conductive paste to a substrate or the like, then burning and removing the binder and heat-treating the fusion between the conductive particles, and the firing temperature means the temperature at which the fusion occurs between the conductive particles, Although it may differ according to the composition of a conductive paste and the kind of electroconductive particle, it generally means the temperature below 1000 degreeC. For example, when copper is used as the conductive particles, the firing temperature may be in the range of 900 to 1000 ° C. (for MLCC), and the firing temperature when silver is used as the conductive particles is 500 to 1000 ° C. (solar cell, MLCC, PDP use). However, the firing temperature is not particularly limited and may be variously controlled according to the characteristics of the oxide material, and thus the conductive copper powder of the present invention may be applied to various electronic devices.

The present invention is characterized by improving the oxidation resistance of the copper powder by coating the surface of the conductive copper powder used for the conductive paste with an oxidation resistant material such as glass or silver (Ag). According to the present invention, the conductive copper powder coated on the surface with an oxidation resistant material may be referred to as a conductive powder having a core-shell structure in which the oxidation resistant material is a shell and the copper is a core. .

In addition, when manufacturing the conductive copper powder coated with the oxidation-resistant material, by using the spray pyrolysis method, it is characterized in that the oxidation-resistant copper powder is relatively easily prepared without undergoing a multi-step process.

According to one embodiment of the present invention, when the surface of the conductive copper powder is coated with glass, it is possible to prevent the contact of copper and oxygen, and to suppress the oxidation of the copper powder at room temperature. When the surface of the copper powder is oxidized, the electrical conductivity drops sharply, and thus may not play a role as an electrode. However, the conductive copper powder coated with the oxidation resistant material according to the present invention has no electrical conductivity of copper itself. Since the electrode can be formed in a non-inhibited state, there is an advantage of forming an electrode having excellent electrical conductivity.

In addition, the glass coated on the surface of the conductive copper powder is composed of the same or similar composition to the glass frit contained in the general conductive paste composition, and thus not only serves as an oxidation resistant material, but also serves as an inorganic binder in the conductive paste. In addition, the inter-particle contact characteristics and the particle-substrate contact characteristics may be improved, and at the same time, the firing temperature of the conductive paste may be lowered. In addition, since the phase separation of the copper powder and the glass frit does not occur in the paste, stable paste production is possible, and since the copper and glass components are uniformly mixed, the formed electrode is very dense and has excellent adhesion property with the substrate.

Therefore, when the conductive copper powder coated with a glass according to the present invention is used for the conductive paste, an electrode having excellent properties can be formed by adding no glass frit or adding only a small amount of glass frit. There is this.

Another embodiment of the present invention may be to coat the surface of the conductive copper powder with silver (Ag).

In the case of silver (Ag), since the oxidation resistance is superior to copper, when the conductive copper powder surface is coated with silver (Ag), contact between copper and oxygen can be prevented, and the oxidation of the copper powder can be suppressed.

In addition, since the melting point of silver (Ag) is lower than that of copper, there is an advantage that the firing temperature can be lowered than when the conductive powder made of copper is used for the conductive paste.

The conductive copper powder of the present invention may have an average particle diameter in the range of 0.1 to 10 μm, but is not limited thereto.

The oxidation resistant material coated on the surface of the conductive copper powder of the present invention is preferably a material having a higher oxidation resistance and a lower firing temperature than the copper powder.

One example of such an oxidation resistant material is oxide glass. The oxide glass may be a glass having a composition generally used for flat glass, display glass, and the like, but may be glass having a composition of glass frit added to the conductive paste, and non-limiting examples thereof include PbO-SiO _2. -P ₂ O ₅ -based glass, PbO-B ₂ O ₃ -based glass, P ₂ O ₅ -ZnO-based glass and SiO ₂ -B ₂ O ₃ -based glass, and more preferably ZnO-B ₂ O _3- SiO ₂ based glass or BaO—B ₂ O ₃ —SiO ₂ based glass.

For example, when BaO-B ₂ O ₃ -SiO ₂ -based glass is used, the composition ratio thereof is 10 to 50% by weight, preferably 20 to 40% by weight, B ₂ O ₃ 30 to 80, based on the total glass weight. Weight percent, preferably 50 to 70 weight percent, SiO ₂ is 3 to 20 weight percent, preferably in the range of 5 to 15 weight percent.

In addition, in addition to the glass former, Al ₂ O ₃ and Na ₂ O may be used in an amount of 0.1 to 10% by weight, preferably 0.1 to 5% by weight, based on the total glass weight.

When the glass having the composition is coated on the surface of the conductive copper powder, the oxidation of the copper powder can be prevented, as well as the firing temperature of the conductive paste can be lowered, and the contact characteristics between the conductive particles or between the conductive particles and the substrate can be improved. have.

It is preferable that the oxide glass is not reduced in a reducing atmosphere of 1000 ° C or less, and preferably, it is not reduced in a reducing atmosphere of 800 ° C or less. Since the conductive paste is generally calcined in a reducing atmosphere of 1000 ° C. or less, when the metal element contained in the oxide glass is reduced and precipitated at such a temperature and atmosphere, there is a possibility that the conductive paste may adversely affect the electrical conductivity and other properties of the electrode. Because.

Meanwhile, another example of the oxidation resistant material may be silver (Ag). Silver (Ag) has a higher oxidation resistance than copper powder and a lower firing temperature, so that silver (Ag) may be coated on the surface of the conductive copper powder to act as a passivation layer.

As can be seen in the examples and comparative examples to be described later, the reaction between the oxidation-resistant material (ex. Oxide glass) and the conductive copper powder does not occur when in the above range, the oxidation-resistant material and the conductive copper powder smoothly in the manufacturing process This is because phase separation can form a surface passivation layer. In addition, sheet resistance characteristics of the formed electrodes are superior to those in the above ranges.

The conductive copper powder coated on the surface of the present invention with an oxidation resistant material is as follows.

A) preparing a precursor solution by dissolving a precursor of copper and a precursor of an oxidation resistant material in a solvent;

B) dropletizing the precursor solution through a spray device;

C) introducing the droplets into a heating device;

D) can be prepared by a method comprising the step of obtaining the powder passed through the heating apparatus.

Hereinafter, the method for preparing the conductive copper powder coated with the oxidation resistant material will be described in detail for each step.

A) preparing a precursor solution by dissolving a precursor of copper and a precursor of an oxidation resistant material in a solvent

The precursors of copper and the precursors of oxidizing materials are not particularly limited as long as they are easily dissolved in a solvent such as water or alcohol. Non-limiting examples include nitrate, acetate, chloride, hydrate ( hydroxide) or an oxide, or the like, may be used in the same manner as described above (for example, a nitrate containing a metal element of copper nitrate and an oxidation resistant material), or a mixture of two or more kinds of precursors May be used (eg, hydrates including metal nitrates of copper nitrate and oxidation resistant materials).

The solvent for dissolving the precursor is also not particularly limited, and non-limiting examples thereof include water, alcohols, acids, other organic solvents, and the like.

When dissolving the precursor of copper and the precursor of the oxidation resistant material in a solvent, the concentration of the solution is not particularly limited, but may preferably be in the range of 0.02 to 3 M.

When the concentration of the solution is less than 0.02M has the effect of reducing the average particle diameter of the powder produced, there is a problem that the productivity of the powder is lowered because the concentration of the solution is low, when the concentration of the solution is larger than 3M There is a problem that grows beyond this need.

When glass is used as the oxidation resistant material, the mixing ratio of the precursor of copper and the precursor of glass is 0.5 to 10 parts by weight based on 100 parts by weight of the copper powder based on the finally synthesized conductive powder. It is preferably in the range, and more preferably in the range of 0.5 parts by weight to 3 parts by weight.

If it is in the said range, a glass component may improve the sintering characteristic of a copper powder, and adhesiveness with a board | substrate may also improve. In addition, it is possible to prevent the deterioration of the conductive property due to the excessive amount of the glass component.

When silver (Ag) is used as the oxidation resistant material, the mixing ratio of the precursor of copper and the precursor of silver (Ag) is based on 100 parts by weight of silver (Ag) based on 100 parts by weight of the copper powder. The weight is preferably in the range of 0.5 to 50 parts by weight, more preferably in the range of 5 to 30 parts by weight, more preferably in the range of 10 to 20 parts by weight.

B) dropletizing the precursor solution through a spray device

A spray device for spraying the precursor solution into the droplets may be used as a spray device commonly used in the art, non-limiting examples of the ultrasonic spray device, air nozzle spray device, ultrasonic nozzle spray device, filter expansion droplet generator ( filter expansion aerosol generator (FEAG), and disk type droplet generator. Preferably an ultrasonic atomizer can be used.

The size of the droplets generated by the spraying device is not particularly limited, but may preferably be in the range of 0.1 to 100 μm.

C) injecting the droplets into a heating device and D) obtaining powder that has passed through the heating device.

When the sprayed droplets are introduced into a heating apparatus, evaporation of the solvent, formation of the porous body of the precursor material, melting of the precursor material, decomposition of the precursor material, formation of a core-shell structure through phase separation of copper and oxidizing materials, densification of particles, etc. Through the process, conductive copper powder particles having a surface coated with an oxidation resistant material are formed.

A schematic diagram of this process is shown in FIGS. 3 and 4.

The conductive copper powder whose surface is coated with an oxidation resistant material by spray pyrolysis can be produced through, for example, the manufacturing apparatus shown in FIG. 1. In particular, in order to synthesize a core-shell structured conductive copper powder having an oxidation resistant material as a shell and a copper as a core by an in situ process, a precursor solution is applied through a spray apparatus. The following principles and conditions are required in the process of the accumulation and the synthesis of the droplets into powder in the heating apparatus.

a) The solubility of the shell material (oxidation resistant material) in copper is very low, resulting in phase separation.

b) has a diffusion rate sufficient to allow the shell material (oxidation resistant material) to diffuse to the surface.

c) no reactants such as M _x Cu _y or M _x Cu _y O _z are produced. (M is the component constituting the shell material)

d) a process temperature sufficient to cause sufficient firing of the shell material.

As a heating apparatus, a conventional heating apparatus used for synthesizing inorganic powder may be used, and non-limiting examples thereof include a box type electric furnace, a tube type electric furnace, and the like, and preferably a continuous type tube furnace. Can be used.

The heating temperature may vary depending on the type of the material in order to cause drying, decomposition and densification of the precursor material, but may range from 600 to 1500 ° C. The composite powder of copper and oxidizing materials obtained through the spray pyrolysis process melts the constituents almost simultaneously with drying and decomposition of the precursor materials when the reactor temperature and the flow rate of the carrier gas are appropriate. In order to lower the spherical shape, one powder is formed in one droplet, so that a composite powder having a passivation layer of submicron units can be synthesized without the need for additional milling and classification.

According to the present invention, the conductive paste may be composed of a composition including an organic binder, a solvent, and other additives, in addition to including the conductive copper powder coated with an oxidation resistant material on the surface as the conductive material, and further adding a glass frit. It may also include.

The organic binder is added to mix the conductive material, glass frit, or other additives, and to have a constant viscosity to maintain the patterned electrode prior to the firing process, an organic binder known to those skilled in the art can be used. . Non-limiting examples of organic binders include acrylic polymers, cellulose polymers, and mixtures thereof.

The solvent is used to prepare a paste that is easy to apply by dissolving the organic binder and adjusting the viscosity of the composition to be prepared, and a solvent known to those skilled in the art can be used. Non-limiting examples of solvents include methyl cellosolve, ethyl cellosolve, butyl cellosolve, aliphatic alcohol, α-terpineol, β-terpine All, Dihydro-terpineol, Ethylene Grycol, Ethylene glycol mono butyl ether, Butyl Cellosolve Acetate, Texanol and Mixtures thereof.

The glass frit serves as an inorganic binder added to improve adhesion with the substrate, and components such as PbO, Bi ₂ O ₃ , SiO ₂ , B ₂ O ₃ , P ₂ O ₅ , ZnO, Al ₂ O _3, and the like. It may be a metal oxide-based glass containing at least one of.

In addition, other additives such as an ultraviolet stabilizer, viscosity stabilizer, antifoaming agent, dispersant, leveling agent, antioxidant, and thermal polymerization inhibitor may be further added as necessary to improve the flow characteristics, process characteristics and stability of the conductive paste. .

Formation of the electrode pattern using the conductive paste may be performed by a method known to those skilled in the art, and non-limiting examples thereof include screen printing, offset printing, coater, photolithography, and DFR (Dry Film Resistor). have.

After the conductive paste is applied to all or part of the substrate as described above, the applied substrate may be baked in a range of 500 to 1000 ° C. to form an electrode. In the electrode manufacturing method of the present invention, the firing temperature of the conductive copper powder may be lower than that of the general copper powder. When silver (Ag) is used as the oxidation-resistant material coated on the surface of the conductive copper powder, since the melting starts from a low temperature, the increase in the resistance of the copper powder may be increased even if it is baked at a low temperature of about 500 ° C. By offsetting, the resistance of the entire conductive powder can be kept low, and when the glass material is used as the oxidation resistant material, the melting temperature of the entire conductive powder can be adjusted according to the composition of the glass. In particular, when glass having the same or similar composition as the glass frit is used, the glass transition temperature is about 600 ° C., so melting occurs at a temperature of 650 ° C. or higher. It can be sintered at a lower temperature than usual to obtain a low resistance value.

On the other hand, the electrode manufactured by the above method can exhibit excellent electrical conduction properties, of course, by lowering the firing temperature of the electrode due to the oxidation-resistant material such as glass, silver coated on the surface to facilitate the formation of the electrode and oxidation resistance When using a glass material as a material, it is possible to simultaneously solve the unevenness and paste instability that may occur in the process of mixing and pasting copper powder and glass frit.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited thereto.

Example 1 Preparation of Conductive Copper Powder Coated with Glass

The conductive copper powder whose surface was coated with glass was prepared by ultrasonic spray pyrolysis.

First, the spray solution is a 0.5 M solution in which Cu (NO ₃ ) ₃ , a precursor of copper, is dissolved in distilled water, and H ₃ BO ₃ , Ba (NO ₃ ) _2, and tetraethylorthosilicate (TEOS), which are precursors of glass, are added to distilled water. The dissolved 0.5 M solution was mixed and prepared by adding a small amount of nitric acid. At this time, the composition of the glass is _{30wt% BaO - 60wt% B 2} O 3 - was controlling the amount of the precursor such that 10wt% SiO _2, the glass weight is in the copper powder 100 parts by weight based on the range of 0.5 to 10 parts by weight of the precursor solution A series of spray solutions with controlled mixing ratios were prepared as experimental sets.

The spray solution was introduced into a spray pyrolysis apparatus to obtain a conductive copper powder having a surface coated with glass.

The spray pyrolysis unit consisted of six ultrasonic spray generators operating at 1.7 MHz, a tubular alumina reactor with an inner diameter of 1000 mm length and 50 mm, and a bag filter, with a pyrolysis temperature of 900 ° C. The flow rate of the air which is a carrier gas was 10 L / min-40 L / min. 5% H ₂ / Ar mixed gas was used as a reducing gas to reduce the oxide form formed after decomposition of copper nitrate to metal during copper powder synthesis.

Example 2 Preparation of Conductive Copper Powder with Surface Coated with Silver (Ag)

The conductive copper powder whose surface was coated with silver (Ag) was prepared by ultrasonic spray pyrolysis.

First, the spray solution is a mixture of 0.5 M solution in which Cu (NO ₃ ) ₃ , a precursor of copper, is dissolved in distilled water, and 0.5 M solution in which Ag (NO ₃ ), a precursor of silver (Ag), is dissolved in distilled water. Prepared by addition. At this time, a series of spraying solutions in which the mixing ratio of the precursor solution was adjusted so that the weight of silver (Ag) was 0.5 to 50 parts by weight based on 100 parts by weight of the copper powder was prepared as an experimental set.

The spray solution was introduced into a spray pyrolysis apparatus to obtain a conductive copper powder coated with silver (Ag).

The spray pyrolysis unit consisted of six ultrasonic spray generators operating at 1.7 MHz, a tubular alumina reactor with an inner diameter of 1000 mm length and 50 mm, and a bag filter, with a pyrolysis temperature of 900 ° C. The flow rate of the air which is a carrier gas was 10 L / min-40 L / min.

5% H ₂ / Ar mixed gas was used as a reducing gas to reduce the oxide form formed after decomposition of copper nitrate to metal during copper powder synthesis.

Comparative Example 1 Preparation of Conductive Copper Powder Without Surface Coating

The conductive copper powder which was not surface coated was prepared in the same manner as in Example 1 except that the precursors of the glass were not mixed.

Example 3 Preparation of Conductive Paste and Conductive Film

The conductive copper powders prepared in Examples 1, 2 and Comparative Example 1 were mixed with ethyl cellulose, α-terpineol, and butyl carbitol acetate (BCA) to conduct conductivity. Paste was prepared. The conductive paste prepared above was screen printed onto an alumina substrate and then dried at 120 ° C. for 30 minutes to remove the solvent. The dried alumina substrate was calcined for 10 minutes at a temperature of 700 ~ 900 ℃. At this time, the temperature increase rate was 5 ℃ / min, and N ₂ was used as the working gas.

5 and 6 show TGA (Thermal Gravimetry Analysis) graphs and Differential Scanning Calorimetry (DSC) graphs of the conductive copper powders prepared in Example 1 and Comparative Example 1, respectively.

In Comparative Example 1, the surface of which is pure copper powder without coating, it can be seen that oxidation occurs at a temperature of 200 ° C. or lower, but in Example 1, where the surface is coated with glass, oxidation of the surface occurs at 300 ° C. or higher. It turns out that the oxidation resistance of electroconductive copper powder improved by doing so. As the oxidation occurs, the copper powder changes from Cu to CuO through Cu ₂ O, and the theoretical mass increase is 25.1%, which is in good agreement with the result shown in FIG. 5.

On the other hand, in the DSC graph of Figure 6, in the case of pure copper powder without a surface coating, T1 temperature is the peak temperature corresponding to the reaction of 4Cu + O ₂ => 2Cu ₂ O, T2 temperature is 2Cu ₂ O + O ₂ => The peak temperature corresponding to the reaction of 4CuO is shown. In the case of the copper powder coated on the surface, the T temperature represents the peak temperature corresponding to the reaction of 2Cu + O ₂ => 2CuO.

Figure 7 shows the TGA and DSC graphs of the conductive copper powder surface-coated with silver (Ag) prepared in Example 2, it can be seen that the oxidation resistance of the conductive copper powder is also improved as in the case of Example 1 .

As can be seen in the TEM photographs of FIGS. 8 and 9, it can be seen that the glass is evenly coated on the surface of the copper powder. As the content of the glass is controlled, the thickness of the coating layer can also be adjusted.

10 shows a TEM photograph and a line profile analysis result of the conductive copper powder prepared in Example 2, and it can be seen that silver (Ag) is coated on the surface of the copper powder.

According to the sheet resistance measurement results of FIG. 11, it can be seen that the sheet resistance value is best when the content of the glass coated on the surface is 0.5 parts by weight to 3 parts by weight based on 100 parts by weight of copper powder. This can also be seen in the XRD results of FIG. That is, when the glass content is 0.5 to 3 parts by weight, no side reaction occurs between the glass and the copper, and the glass component may be moved to the surface of the conductive copper powder to form a uniform coating layer, but the content of the glass is increased. In this case, it is thought that the synthesis of the glass easily occurs to form a shell structure, so that the copper oxide inside is not reduced to the copper metal by the reducing gas and remains in the oxide form.

According to FIG. 13, when the surface of the conductive copper powder is coated with silver (Ag), the surface of the conductive copper powder is melted at a lower temperature than the uncoated surface, and thus the sheet resistance value is lower. In particular, it can be seen that as the content of silver (Ag) increases, the sintering characteristics are improved, so that voids in the conductive film are reduced, and electrical characteristics are further improved.

Claims (15)

a) preparing a precursor solution by dissolving a precursor of copper and a precursor of an oxidation resistant material in a solvent;
b) dropleting the precursor solution through a spray device;
c) introducing the droplets into a heating device;
d) obtaining a powder that has passed through the heating apparatus,
Method for producing a conductive copper powder coated on the surface with an oxidation resistant material. The method of claim 1, wherein the oxidation resistant material is oxide glass or silver (Ag). The method of claim 2, wherein the oxide glass is ZnO-B ₂ O ₃ -SiO ₂ -based glass or BaO-B ₂ O ₃ -SiO ₂ -based glass. The method of claim 2, wherein the content of the oxide glass is in the range of 0.5 parts by weight to 10 parts by weight based on 100 parts by weight of the copper powder. The method of claim 2, wherein the content of silver (Ag) is in the range of 0.5 parts by weight to 50 parts by weight based on 100 parts by weight of the copper powder. The method of claim 1, wherein the precursor of copper and the precursor of the oxidation resistant material are each independently selected from the group consisting of nitrate, acetate, chloride, hydrate, and oxide. The manufacturing method of the electroconductive copper powder characterized by the above-mentioned. A conductive copper powder coated on the surface with an oxidation resistant material, wherein the oxidation resistant material has a higher oxidation resistance than the copper powder. 8. The conductive copper powder of claim 7, wherein the oxidation resistant material is oxide glass or silver (Ag). The conductive copper powder of claim 8, wherein the oxide glass is ZnO-B ₂ O ₃ -SiO ₂ -based glass or BaO-B ₂ O ₃ -SiO ₂ -based glass. The conductive copper powder according to claim 8, wherein the content of the oxide glass ranges from 0.5 part by weight to 10 parts by weight based on 100 parts by weight of the copper powder. The conductive copper powder of claim 8, wherein the silver (Ag) is in a range of 0.5 part by weight to 50 parts by weight based on 100 parts by weight of the copper powder. The electroconductive copper powder of Claim 7 whose average particle diameter is the range of 0.1-10 micrometers. The electroconductive paste containing the electroconductive copper powder in any one of Claims 7-12. Applying the conductive paste of claim 13 to all or part of the substrate; And
The method of manufacturing an electrode comprising the step of forming the electrode by firing the applied substrate in the range 500 ~ 1000 ℃. The electrode manufactured by the method of Claim 14.

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