JPH09198920A - Copper conductor paste and circuit board printed with copper conductor paste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make printing easily on a ceramic base board, retain the shape even after printing, fill through holes in the base board easily to enable fastening, and lower the resistance of the conductor. SOLUTION: Copper, copper oxides, and/or mixture thereof in the form of particulates are dispersed in a highpolymer substance without coagulation to form a highpolymer composite, and thereto copper, copper oxides, and/or mixture thereof having a mean particle size of 1-100nm, a mixture copper powder, and an organic solvent are added, wherein the mixture copper powder chiefly contains base copper powder having a mean particle size of 0.5-10μm to which one sort or more of aux. copper powder having a smaller mean particle size is added.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper conductor paste and a substrate on which the paste is printed. More specifically, it is easy to print on the substrate, can retain its shape after printing, and can be filled in through holes provided in a ceramic substrate. The present invention relates to a copper conductor paste that is easy to perform and a substrate on which the copper conductor paste is screen-printed.

[0002]

2. Description of the Related Art Today, a conductor paste is used for printing a circuit on a ceramic substrate and filling a conductor in a through hole which is a through hole formed in the substrate. Examples of the conductor paste include Ag-Pd-based pastes containing silver and palladium as main components, silver-based pastes,
There are gold-based pastes, Ag-Pt-based pastes containing silver and platinum as main components, and copper-based pastes.

Of these, the Ag-Pd type paste is typical for wiring, but it also has some problems. For example, when the paste is used for wiring on the substrate, silver ionizes via moisture in the air, and this ionized silver migrates to the adjacent conductor path, causing a phenomenon called migration that short-circuits the circuit. Was there. Therefore, the distance between the conductor paths cannot be reduced. Further, in the soldering portion for mounting or connecting other components on the conductor path, silver is easily eroded by the solder, and the solder resistance is poor.

Further, when the above paste is adhered to the substrate, since essentially micron-sized metal fine particles cannot react and adhere to the ceramic substrate, about 4 to 10% by weight of glass frit is mixed in the paste. However, the glass frit on the substrate after printing has a role of adhering the substrate and the metal film after firing. However, on the other hand, since a large amount of glass frit remains in the metal film after firing,
Since the electric resistance value of the metal film becomes high and the glass film adheres the metal film to the substrate, distortion due to the difference in thermal expansion easily occurs, and the thermal shock resistance becomes weak.

A copper-based paste is known as a paste that partially solves such problems. For example, as described in JP-A-60-70746, this paste has a composition in which a non-copper-based substance such as copper, glass firit, and tungsten, molybdenum, and rhenium is dispersed in an organic solvent. In addition, 3-50
As described in JP-A-365, it has a composition in which metallic copper particles coated with copper oxide, copper oxide particles, and glass powder such as glass are dispersed in an organic solvent.

Further, as a method of manufacturing a substrate having other through holes filled therein, there has been proposed a method of simultaneously firing alumina through holes having tungsten buried therein.

[0007]

The above copper-based paste also plays a role of adhesion between the substrate and the conductor by adding a large amount of glass frit, preferably 4 to 10% by weight, as glass powder. However, the above-mentioned paste has a low dynamic viscosity in order to improve printability, but since the static viscosity is also low, when the paste is screen-printed on the substrate, the paste sags and the conductor after printing is printed. The edges did not appear sharply and accurate printing could not be performed. Therefore, it leads to the problem that the conductor cross-sectional area is difficult to grasp due to the circuit design. On the other hand, if the viscosity is increased, the printability deteriorates, and the conductor path becomes uneven, and this unevenness causes noise in the electrical signal. There was an occasion.

Further, when the through holes are filled up and then fired to fill the inside, a large amount of glass frit remains in the conductors in the through holes after the firing, so that the electric resistance value of the conductor is reduced. In addition, the glass layer existing at the interface between the conductor and the substrate is liable to be distorted due to the difference in thermal expansion, resulting in weak heat resistance and thermal shock resistance, and there is a problem that the filled conductor does not adhere to the through hole. This thermal shock resistance is evaluated from the adhesive force between the conductor and the substrate after the substrate having the conductor is repeatedly moved from the low temperature atmosphere to the high temperature atmosphere and vice versa. Further, since lead borosilicate glass having a low softening point is also used for the glass frit, lead in the glass hinders the plating in the plating process performed for oxidation prevention and Au wire bonding.

The present invention solves such a problem, and it is easy to print on a substrate, the shape can be retained after printing, and it is easy to fill a through hole provided in a ceramic substrate and to fix it. It is an object of the present invention to provide a copper conductor paste in which the electric resistance of the conductor is reduced and a substrate on which the copper conductor paste is printed.

[0010]

Means for Solving the Problems That is, the present invention provides a polymer composite obtained by dispersing ultrafine-grained copper oxide, copper, or a mixture thereof in a polymer without aggregating, Copper, copper oxide, or a mixture thereof having a particle diameter of 1 to 100 nm, and an average particle diameter of 0.5 to 1
Printed using a mixed copper powder mainly containing a base copper powder in the range of 0 μm and at least one auxiliary copper powder having an average particle size smaller than that, and a copper conductor paste made of an organic solvent and the copper conductor paste. And then on the baked substrate.

In the present invention, when a binder resin is added, or when the mixed copper powder has the largest average particle size in the range of 2 to 5 μm, the base copper powder and the average particle size of 1 to 2 are used.
In the case where it is composed of the first auxiliary copper powder in the range of 0.5 μm and the second auxiliary copper powder in the range of 0.5 to 1 μm in average particle size, or the mixed copper powder has an average particle size of 0. 5-1
In the case where the base copper powder having the largest average particle diameter in the range of μm and the auxiliary copper powder having the average particle diameter in the range of 0.1 to 0.5 μm are used, or the glass powder is mixed with the mixed copper powder and the polymer composite. 0 per 100 parts by weight of the total amount of ultrafine-grained copper, copper oxide, or a mixture thereof, and copper, copper oxide, or a mixture thereof having an average particle diameter in the range of 1 to 100 nm. 1 to 2.0 parts by weight is added, or the organic content of the organic solvent and the polymer is 2-1.
Including the case of 6 wt%.

[0012]

In the copper conductor paste of the present invention and the substrate printed with the copper conductor paste, the ultrafine particles of copper, copper oxide, or a mixture thereof are dispersed in the polymer without being agglomerated and Molecular composite and average particle size 1-100
Copper, copper oxide, or a mixture thereof in the range of nm has a function of reacting and adhering to the substrate and baking the mixed copper powder. Further, the mixture of the mixture and the mixed copper powder in the polymer composite has a high static viscosity, the edges of the conductor after printing appear sharp and the shape retention is good, and the dynamic viscosity is high. Therefore, the printability is good.
Further, copper, copper oxide, or a mixture thereof having an average particle diameter in the range of 1 to 100 nm has a function of reacting and adhering to the substrate and hardening the mixed copper powder. Further, the auxiliary copper powder fills the gaps and voids generated by the arrangement of the base copper powders, so that it is possible to obtain a conductor having no internal defects and having a good compaction. Further, by making the base copper powder smaller, it can be applied to fine line printing. Moreover, by adjusting the viscosity of the conductor paste, it is easy to fill the through holes, and since the volume change of the paste filled in the through holes does not change after firing, the hole filling property is good and a high level of adhesive strength is maintained. it can.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A polymer composite, which is the first component of a copper conductor paste in the present invention, is a thermodynamically non-equilibrium polymer layer prepared and at least copper is provided on the surface of the polymer layer. After adhering the metal, the polymer layer is heated to stabilize the polymer layer, and thus Cu ₂ O is formed from copper metal into ultrafine particles having a particle size of 100 nm or less, preferably 1 to 50 nm.
Alternatively, copper oxide made of CuO, copper, or a mixture thereof is dispersed in the polymer without agglomeration. The content of ultrafine copper oxide particles is 90% by weight or less,
It is preferably 10 to 90% by weight. Ultra-fine particles of copper oxide, copper, or a mixture of these have high reactivity at low temperatures, accelerate the sintering of copper powders, and form a conductive film with strong adhesion by reaction and adhesion with the substrate. .

When obtaining the above polymer composite, it is necessary to form the polymer layer in a thermodynamically non-equilibrium state. Specifically, this is a vacuum deposition method in which a polymer is heated in a vacuum to melt and evaporate to solidify a polymer layer on a substrate, or a thermal decomposition method, the polymer is melted at a melting temperature or higher, In this state, there is a method such as a rapid quenching solidification method in which the polymer layer is immediately put into liquid nitrogen or the like to be rapidly cooled and a polymer layer is attached onto the substrate.

In the case of the vacuum vapor deposition method, a vacuum degree of 10 ⁻⁴ to 10 ⁻⁶ Torr and a vapor deposition rate of 0.1 to 100 μm / min, preferably 0.
At 5 to 5 μm / min, a polymer layer can be obtained on a substrate such as glass.

In the thermal decomposition method, a polymer as a raw material is thermally decomposed and vaporized in a closed space under reduced pressure, and the vaporized substance is solidified to a thermodynamically nonequilibrium state (metastable structure). A method for producing a recycled polymer, in which a predetermined amount of the charged polymer is thermally decomposed and vaporized, and then this vaporized substance is agglomerated into the regenerated polymer in the heat treatment region, and the vaporized substance is not agglomerated. Is a method of obtaining a regenerated polymer in which the oily low molecular weight substance is not mixed by aggregating with the oily low molecular weight substance in the cooling region.

In the melting rapid solidification method, the polymer is melted and cooled at a rate not lower than the critical cooling rate specific to the polymer to obtain a polymer layer. The polymer layer thus obtained is placed in a thermodynamically unstable non-equilibrium state, and shifts to an equilibrium state with the passage of time.

The polymer used in the present invention is, for example, nylon 6, nylon 66, nylon 11, nylon 12, nylon 69, polyethylene terephthalate (PET),
Polyvinyl alcohol, polyphenylene sulfide (P
PS), polystyrene (PS), polycarbonate, polymethylmethacrylate, etc., which have a molecular cohesive energy of 2000 cal / mol or more are preferable. This polymer includes a crystalline polymer and an amorphous polymer which are usually called. Regarding the molecular cohesive energy, the Chemical Handbook, edited by the Chemical Society of Japan (edited in 1974)
890, page 890.

Subsequently, the thermodynamically non-equilibrium polymer layer is transferred to the step of adhering a copper metal layer to the surface thereof. In this step, a copper metal layer is vapor-deposited on the polymer layer by a vacuum vapor deposition apparatus, or a metal foil or a metal plate is directly adhered to the polymer layer to laminate the copper metal layer to the polymer layer. .

The composite in which the metal layer of copper and the polymer layer are in close contact with each other is heated at a temperature not lower than the glass transition point of the polymer and not higher than the flow temperature to shift the polymer layer to a stable state. As a result, the copper metal layer becomes ultrafine particles of copper oxide, copper, or a mixture thereof having a maximum particle size distribution in the region of 1 to 50 nm at 100 nm or less, and diffuses and permeates into the polymer layer. This state continues until the polymer layer is completely stable, and the copper metal layer adhering to the polymer layer also decreases in thickness and finally disappears. The ultrafine particles are distributed in the polymer layer without being aggregated. When the polymer layer is heated in this step, the polymer layer exhibits unique coloring due to the interaction with the ultrafine particles of copper oxide, copper, or a mixture thereof, and the ultrafine particles penetrate into the polymer layer. You can see that Further, this color can change depending on the particle size of ultrafine particles made of copper oxide, copper, or a mixture thereof, and the type of polymer.

In the present invention, the method for producing the polymer composite is not limited to the above-mentioned method, and for example, the vapor phase method belonging to the melt vaporization method, the liquid phase method belonging to the precipitation method, the solid phase method, the copper oxide by the dispersion method,
A method of producing ultrafine particles of copper or a mixture thereof and mechanically mixing the ultrafine particles with a polymer consisting of a solution or a melt, or simultaneously evaporating the polymer and the ultrafine particles and mixing them in a gas phase There are ways to do it.

The fine particles of copper, copper oxide, or a mixture thereof, which are the second component of the copper conductor paste of the present invention, are prepared by, for example, a method called precipitation method, that is, a reducing agent is used from a metal salt solution. This is a method of directly depositing metal fine particles. The metal fine particles can be obtained by adding a reducing agent such as formalin, hydrazine, sodium hypophosphite, and borohydride under an appropriate condition to an aqueous solution containing metal ions. The fine particles are surface-treated with an organic fatty acid or a coupling agent in order to improve the oxidation resistance and dispersibility. The average particle size of the fine particles is in the range of 1 to 100 nm, preferably 40 to 6
It is 0 nm.

The mixed copper powder, which is the third component of the copper conductor paste of the present invention, is based on copper powder having an average particle diameter of 0.5 to 5 μm, and the average particle diameter is smaller than this. At least 1 to 3 or more kinds of auxiliary copper powder are added. The specific mixed copper powder has an average particle diameter of 2 to 5 μm.
In the range of the largest average particle size, the first auxiliary copper powder having the next largest average particle size in the range of average particle size 1-2 μm, and the range of 0.5-1 μm in average particle size. Of the second auxiliary copper powder having the smallest average particle diameter, the average particle diameter of 0.
A base copper powder in the range of 5 to 1 μm and an average particle diameter of 0.
It is composed of a two-step particle size range of the auxiliary copper powder in the range of 1 to 0.5 μm. In the case where the mixed copper powder is composed of three stages of particle diameter ranges, in the mixed copper powder, the base copper powder is 80 to 98 wt% and the first auxiliary copper powder is 1 to 19%.
%, And the second auxiliary copper powder is 1 to 19% by weight. In particular, the auxiliary copper powder is not limited to this, and a third auxiliary copper powder having an average particle diameter within the range may be used.

It is desirable that each of the auxiliary copper powders has a relatively spherical shape. This is because each copper powder is arranged with a small number of voids. When copper powders with different average particle diameters are used, auxiliary copper powders with a small average particle diameter fill the gaps and voids generated when the base copper powder with the largest average particle diameter is arranged, so the conductor after firing is There are few internal defects, and it has the effect of making baking tight.

When the average particle size of the base copper powder exceeds 5 μm, it is less susceptible to oxidation and the setting of firing conditions becomes wider, but at low temperatures it does not sinter sufficiently and insufficient tightening occurs, resulting in a failure of the conductor and the substrate. The adhesive strength is reduced. Further, in the ink roll process, the copper powder may be crushed to form a copper foil, which may cause mesh clogging during screen printing. On the other hand, if the average particle size of the base copper powder is less than 0.5 μm, the total particle area of the mixed copper powder becomes too large, the influence of oxidation becomes large, and the electric resistance value becomes high. Further, since the bulk density is high, the shrinkage tightness becomes poor.

If the amount of the base copper powder added exceeds 98% by weight, sintering will not be sufficiently performed at a low temperature and insufficient tightening will occur, resulting in a decrease in the adhesive force between the conductor and the substrate or through holes. If it is less than 10% by weight, the total particle area of the mixed copper powder becomes too large, and the same problem as described above occurs. The auxiliary copper powder is added to fill the gaps and voids generated when the base copper powder is arranged, and the average particle size and the addition amount are greatly influenced by those of the base copper powder.

Examples of the organic solvent include carbitol, carbitol acetate, metacresol, dimethylimidazolidinone, dimethylformamide, terpinol,
It is a high boiling organic solvent such as diacetone alcohol, triethylene glycol, paraxylene, ethyl lactate, and isophorone, and two or more kinds thereof may be mixed.

The fourth component, glass powder, added to the present invention may be added in order to improve the cracking of the conductor and to support the auxiliary role of improving the tightening. This glass powder does not contain lead, has a softening point of 200 to 700 ° C. in the range of average particle diameter of 1 to 10 μm, and its addition amount is all copper powder and ultrafine copper oxide. 0.1 to 2.0 parts by weight is preferable for 100 parts by weight of the total amount of the alloy, copper, or a mixture thereof. 2.0
If it exceeds the weight part, the glass powder remains in the conductor after firing, so that the electric resistance value of the conductor tends to increase, and a glass layer is formed at the interface between the conductor and the substrate to prevent distortion due to thermal expansion. It is easy to cause and the thermal shock resistance becomes weak. on the other hand,
If it is less than 0.1, the cracking of the conductor and the improvement of baking cannot be expected.

A polymer other than the polymer of the polymer composite may be added as a binder resin to the copper conductor paste of the present invention. Examples of the resin include celluloses such as nitrocellulose, ethyl cellulose, cellulose acetate and butyl cellulose, polyethers such as polyoxymethylene, polyvinyls such as polybutadiene and polyisoprene, and acrylates such as polybutyl acrylate and polymethyl acrylate. , Nylon 6, nylon 6.
6, polyamide such as nylon 11.

In the copper conductor paste of the present invention, the organic content composed of the organic solvent and the polymer (including the binder resin) is in the range of 2 to 16% by weight. When the organic content is less than 2% by weight, the viscosity of the conductor paste becomes high and it becomes difficult to fill the through holes. When the organic content exceeds 14% by weight, the paste filled in the through holes shrinks due to firing. Therefore, the hole filling property becomes poor.

Further, all the contained copper powder and fine copper oxide, copper, or a mixture thereof are in the range of 84 to 98% by weight. If it exceeds 98% by weight, the paste becomes highly viscous and insufficiently hardened to reduce the adhesive force between the conductor, the substrate and the through holes, while if less than 84% by weight, the paste filled in the through holes shrinks due to firing. Therefore, the same problem as described above occurs.

The conductor paste thus obtained is
It is applied to a ceramic substrate such as alumina, aluminum nitride, silicon carbide, silicon nitride, sialon, barium titanate, or PBZT by a method such as screen printing. In the screen printing procedure, a printed board is placed under a horizontally placed screen (for example, stainless steel plain weave, 300 mesh) with a space of several millimeters. After placing the conductive paste on this screen, spread it over the entire screen using a squeegee. At this time, there is a gap between the screen and the printed board. Then, the squeegee is pressed against the screen so that the screen comes into contact with the printed board, and the screen is moved to perform printing. After that, this is repeated.

This is placed in an oven set at 100 to 200 ° C. and dried. In the pre-baking step, the temperature is gradually raised from this set temperature to 300 ° C. at a heating rate of 2 to 20 ° C./minute, and then held at this temperature for a maximum of 60 minutes, during which the decomposition behavior of the organic component is adjusted. . When this is over,
Put the pre-baked substrate in a belt furnace, in nitrogen, 600-10
Baking is performed at a temperature of 00 ° C. for 5 to 20 minutes (peak holding time) to sinter the copper powder and react and adhere to the substrate.

[0034]

Next, the present invention will be described in more detail with reference to specific examples. Examples 1 to 5 and Comparative Example 1 (Preparation of Polymer Composite) Using a vacuum vapor deposition apparatus, 5 g of polymer pellets of nylon 11 were put into a tungsten board and the pressure was reduced to 10 ⁻⁶ Torr. Then, a voltage is applied to heat the tungsten board in a vacuum to melt the polymer, and a substrate (glass plate) installed on the upper part of the mounting table is vacuumed at a pressure of 10 ⁻⁴ to 10 ⁻⁶ Torr to a degree of about 1 μm.
A polymer layer of a vapor-deposited film having a thickness of about 5 μm was obtained at a rate of / min.
The molecular weight of this polymer layer is 1/2 that of the polymer pellets.
It is about 1/10.

Further, a copper chip was placed in a hearth, heated and melted by an electron beam, and vapor deposition was performed at a vacuum degree of 10 ⁻⁴ to 10 ⁻⁶ Torr to deposit a copper vapor deposition film on the polymer layer. This was taken out from the vacuum vapor deposition apparatus and left in a constant temperature bath kept at 120 ° C. for 10 minutes to obtain a composite. As a result, this polymer composite contained 40% by weight of Cu ₂ O and had a particle size of 1 to 15 nm.

(Preparation of Copper Conductor Paste) Polymer Composite,
Cu or Cu ₂ O having a particle diameter of 40 nm, mixed copper powder, an organic solvent, and glass powder were mixed as shown in Table 1. 3 consisting of base copper powder and two types of auxiliary copper powder as mixed copper powder
Seeds used. A brown conductor paste was prepared by mixing the above and further uniformly mixing with an ink roll.

(Production of Conductor) As a substrate for evaluating the adhesive strength, a conductive paste was used in 2 × using a polyester 200 screen.
It is printed on 2 mm and the electric resistance evaluation substrate is a conductor paste with a diameter of 1 using a polyester 200 screen.
Printed to 5 mm. Further, as the through-hole evaluation substrate, a conductor paste was screen-printed on an alumina substrate having a plurality of through-holes with a diameter of 0.3 mm using a polyester 200 screen, and at the same time, the conductor paste was pressed into the through-holes. These were placed in an oven set at 80 ° C., heated to 260 ° C. at a heating rate of 5 ° C./min, held for 10 minutes, and prebaked. Then, the pre-baked substrate is put into a belt furnace and the oxygen concentration is 0 to 10 in nitrogen.
A substrate was produced by firing at a firing temperature of 900 ° C. ppm for a peak holding time of 15 minutes.

(Evaluation method) Adhesive strength of the conductor after firing, electric resistance value of the conductor, and adhesiveness of the through hole filling portion,
The hole filling property and the printed edge were measured by the following methods.

1. Adhesive strength of conductor film after firing (L-shaped peel strength) 2 mm of L-shaped bent tin-plated copper wire with a diameter of 0.8 mm
The adhesive force of the copper wire, which was fixed by soldering to the surface of a conductor fired to a size of 2 mm and bent vertically, was measured by a spring measure to determine the adhesive force between the substrate and the conductor.

2. Electric resistance value of conductor The electric resistance value was measured by a four-point probe method using a conductor having a thickness of 10 μm and a diameter of 15 mm on an alumina substrate.

3. Adhesiveness of through-hole filling area 100 through-hole filling area with Taber abrasion tester
The state after zero wear was visually observed. The evaluation is on a three-point scale: ⊚ is excellent, ∘ is good, and Δ is bad.

4. Hole filling property The hole filling part of the through hole was observed with a microscope. The evaluation is on a three-point scale: ⊚ is excellent, ∘ is good, and Δ is bad.

5. Printing edge Horizontally laid screen (polyester plain weave, 20
(0 mesh) at a distance of a few millimeters, the printed board is placed, the conductive paste is placed on this screen, and then spread over the entire surface of the screen using a squeegee, and then the screen contacts the printed board. Press the screen with a squeegee and move it to print. The printed board was enlarged with a microscope to observe the edges of the conductor. The edges were sharp and angular, and the edges were round, and the central portion was flat, and the edges were round, and the central portion was dented.

6. Viscosity A viscometer (DVO-E type) manufactured by Tokyo Keiki Co., Ltd. was used, and No. The rotor of No. 9 was put in and rotated, and static viscosity (rotor rotation 1 rpm) and dynamic viscosity (rotor rotation 5 rpm) were measured. Measurement temperature is 25 ° C
It is. The results obtained by the above evaluation method are shown in Table 1.

[0045]

[Table 1]

According to these results, in the example, it is easy to fill the through holes, the filling property of the paste filled in the through holes after firing is good, and it is easy to print on the substrate, and the shape after printing is good. It turns out that it can be held.
However, in the comparative example, some print edges are bad.

[0047]

INDUSTRIAL APPLICABILITY As described above, in the copper conductor paste of the present invention and the substrate printed with the copper conductor paste, the edges of the conductor after printing appear sharply due to the improvement of the static viscosity, and the shape retention is good. Moreover, the printability is good because the dynamic viscosity is low. In addition, since the auxiliary copper powder fills the gaps and voids generated by the arrangement of the base copper powder, it is possible to obtain a conductor having no internal defects and good tightness.
Also, by making the base copper powder smaller, it can be applied to fine line printing. And it is easy to fill the through holes by adjusting the viscosity of the conductor paste,
Since there is little change in the volume of the paste filled in the through holes after firing, it has excellent hole filling properties and has an excellent effect of maintaining a high level of adhesive strength.

Claims (9)

[Claims] 1. An average particle diameter of 1 to 100 nm is added to a polymer composite obtained by dispersing ultrafine copper, copper oxide, or a mixture thereof in a polymer without agglomerating.
Of copper, copper oxide, or a mixture thereof in the range of 0.1 to 10%, and at least one or more auxiliary copper powders having an average particle size of 0.5 to 10 μm and mainly having a smaller average particle size than this A copper conductor paste comprising the above mixed copper powder and an organic solvent. 2. The copper conductor paste according to claim 1, wherein a binder resin is added. 3. A polymer layer in which a polymer composite is thermodynamically non-equilibrium is prepared, and a copper metal layer is adhered to the surface of the polymer layer, and then the polymer layer is heated to a high temperature. The method according to claim 1, which is obtained by dispersing ultrafine particles of copper, copper oxide, or a mixture thereof formed into ultrafine particles from the metal layer by stabilizing the molecular layer without agglomerating in the polymer. Copper conductor paste. 4. A base copper powder having the largest average particle diameter in the mixed copper powder having an average particle diameter of 2 to 5 μm, and an average particle diameter of 1
The copper conductor paste according to claim 1 or 2, which is composed of a first auxiliary copper powder having a particle size of ˜2 μm and a second auxiliary copper powder having an average particle size of 0.5 μm to 1 μm. 5. The mixed copper powder is composed of a base copper powder having the largest average particle diameter in the range of 0.5 to 1 μm and an auxiliary copper powder in the average particle diameter of 0.1 to 0.5 μm. The copper conductor paste according to claim 1 or 2. 6. A glass powder, copper mixed with copper powder, ultrafine-grained copper in a polymer composite, copper oxide, or a mixture thereof, and copper or copper oxide having an average particle diameter in the range of 1 to 100 nm. Or a total amount of these mixtures of 100
The copper conductor paste according to claim 1, 2, 3, 4, or 5, which is added in an amount of 0.1 to 2.0 parts by weight with respect to parts by weight. 7. The organic component composed of an organic solvent and a polymer is 2 to
The copper conductor paste according to claim 1 or 2, which is in the range of 16% by weight. 8. A polymer composite obtained by dispersing ultrafine-grained copper, copper oxide, or a mixture thereof in a polymer without agglomerating, has an average particle diameter of 1 to 100 nm.
Of copper, copper oxide, or a mixture thereof in the range of 0.1 to 10%, and at least one or more auxiliary copper powders having an average particle size of 0.5 to 10 μm and mainly having a smaller average particle size than this A substrate on which a copper conductor paste is printed, which is obtained by printing a copper conductor paste obtained by adding the mixed copper powder prepared above and an organic solvent, and baking the copper conductor paste. 9. A glass powder, copper mixed with copper powder, ultrafine-grained copper or copper oxide in a polymer composite, or a mixture thereof, and copper or copper oxide having an average particle diameter in the range of 1 to 100 nm. Or a total amount of these mixtures of 100
The substrate according to claim 8, which is added in an amount of 0.1 to 2.0 parts by weight with respect to parts by weight.