JPH04345701A - Solderable copper group conductive paste - Google Patents

Abstract

PURPOSE:To provide solderable conductive paste by copper group PTF. CONSTITUTION:Solderable conductive paste consisting of copper alloy powder, in which silver is condensed at high concentration on the grain surface obtained in an atomizing method, an additive capable of removing copper oxide from the grain surface, elusion and a titanium coupling agent, a phenol group organic binder is obtained. The composite is solderble conductive paste excellent in oxidation resistance, solder corrosion resistance and migration resistance while being applicable to a conductive circuit, an electrode material, an electromagnetic wave shield and a conductive adhesive agent. Thereby, paste excellent in conductivity, oxidation resistance, and migration resistance is obtained.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a copper-based conductive paste that has excellent conductivity, oxidation resistance, migration resistance, and is solderable, and a conductor using the paste. It can be used as shields, conductive adhesives, pastes for conductive circuits, pastes for electrodes, pastes for screen printing, pastes for printed resistors, pastes for through holes, pastes for capacitor electrodes, and contact materials.

0002

BACKGROUND OF THE INVENTION Known conductive pastes used have the following drawbacks. Copper is inexpensive, but its conductivity tends to decrease due to oxidation. In addition, attempts have been made to add antioxidants to pastes using copper powder, but initially conductivity is obtained by removing the copper oxide on the powder surface, but after the coating is formed, At high temperatures or high humidity, the particle surfaces are oxidized, gradually increasing contact resistance and impairing conductivity. Therefore, soldering was poor, and it was difficult to solder to conductive paste using copper.

[0003]Although conductive pastes using silver powder are known, they tend to migrate easily and suffer from solder erosion, and cannot provide sufficient adhesion strength of the coating film. Conductive pastes using copper powder plated with silver are also known (for example, JP-A-3-21659), but these pastes have problems such as peeling during kneading and poor silver migration resistance.

0004

SUMMARY OF THE INVENTION The present invention provides a copper-based conductive paste that has good conductivity, oxidation resistance, migration resistance, and is solderable, and products using the same.

[0005]

[Means for Solving the Problems] The present invention for solving the above problems includes: 1. General formula AgxCuy (where 0
．． 001≦x≦0.999, 0.001≦y≦0.99
9, x+y=1, atomic ratio) copper alloy powder 10
0 parts by weight, 5 to 100 parts by weight of a phenolic organic binder, 0.001 to 3 parts by weight of a titanium coupling agent, and 0.01 to 100 parts by weight of an additive capable of removing copper oxides. conductive paste. 2. Copper alloy powder represented by the general formula AgxCuy is 0
．． In the range of 001≦x≦0.4, 0.6≦y≦0.999 (atomic ratio), the silver concentration on the surface of the copper alloy powder particle is higher than the average silver concentration, and near the surface, the silver concentration is higher than the inside than the inside. 2. The solderable copper-based conductive paste according to claim 1, wherein the solderable copper-based conductive paste has a region in which the silver concentration increases.

The present invention will be explained in detail below. The copper alloy powder used in the present invention is produced by an atomization method. The gas atomization method and the water atomization method are preferred, and the inert gas atomization method is particularly preferred. Regarding the inert gas atomization method used in the present invention, the method described in JP-A-2-282401, which was invented by the present inventors, is preferred. For example, copper, silver mixtures, or alloys of such composition are melted in a crucible in an inert atmosphere or in vacuum using high frequency induction heating. At this time, the inert atmosphere means an atmosphere that does not react with the melt at all or reacts only very slowly. For example, nitrogen,
An atmosphere containing helium, hydrogen, and argon as main components is preferable. Furthermore, the melt is spouted from the tip of the crucible into an inert gas atmosphere. At the same time as the ejection, a high-speed airflow generated by adiabatically expanding compressed inert gas is ejected toward the melt to atomize it. Inert gas, as used herein, means a gas that does not react at all or reacts only very slowly with a melt of such composition. For example, nitrogen, helium, argon, hydrogen, and mixtures thereof are preferred. At this time, the oxygen contained in the gas is preferably 2% or less, more preferably 0.1% or less.

The pressure of the gas (just before expansion) is 5 kg/cm
2 G or more is preferable, and 15 kg/cm2 G or more is more preferable. The speed of the high-speed airflow is preferably 50 m/sec or more at the collision position with the melt, more preferably 100 m/sec or more, and most preferably 300 m/sec or more. The mass velocity ratio between gas and melt (gas mass velocity/melt mass velocity) is 0.
．． One or more is preferable, and one or more is more preferable. Also,
The cooling rate at this time is preferably 102°C/second to 109°C/second, more preferably 103°C/second to 107°C/second.

AgxCuy used in the present invention (however, 0
．． 001≦x≦0.999, 0.001≦y≦0.99
9, x+y=1, atomic ratio), but x is 0.001
If it is less than that, sufficient oxidation resistance and solderability cannot be obtained.
Further, when x exceeds 0.999, migration resistance and solder erosion resistance are insufficient. When the copper alloy powder used in the present invention satisfies 0.001≦x≦0.4, the silver concentration on the powder surface is higher than the average silver concentration, and the silver concentration near the surface decreases from the inside toward the surface. The surface silver concentration is 2.1 times or more higher than the average silver concentration. Preferably, it is 3 times to 40 times, and more preferably 4 times to 15 times. The silver amount x is preferably 0.0
05≦x≦0.3, more preferably 0.01≦x≦0.25.

[0009] The copper alloy powder of 0.001≦x≦0.4 used in the present invention has a surface silver concentration higher than the average silver concentration, but the mechanism by which low melting point silver is concentrated on the surface is as follows.
As already disclosed by the present inventors (Japanese Unexamined Patent Publication No.
-282401), and can be considered as follows. For example, fine metal droplets generated by collision with high-speed airflow gas are accompanied by the high-speed airflow and rapidly solidify while traveling at high speed. It is thought that during this solidification process, a liquid phase rich in silver with a low melting point is discharged to the surface and solidifies with a delay, forming a powder with concentrated silver on the surface.

When using the water atomization method, a molten copper alloy is jetted out from the tip of a crucible. At the same time as the ejection, pressurized water is ejected from the nozzle toward the melt ejected from the nozzle tip, collides with the melt, becomes fine particles, and rapidly solidifies. At this time, the ratio of mass velocity of water to mass velocity of melt is preferably 10 or more, more preferably 40 or more. Further, the speed of the water at the collision position of the water and the melt is preferably 80 m/sec or more, and more preferably 100 m/sec or more. The pressure when pressurized water is ejected from the nozzle tip is preferably 50 kg/cm2 G or more, and further 1
00 kg/cm2 G or more is preferable.

[0011] When the silver amount x exceeds 0.4, (0.4
≦x≦0.999), it can be used especially when oxidation resistance at high temperatures is required. In this case, the migration resistance is high because the silver in the powder is alloyed with copper, and the concentration of silver on the surface is high, and since silver is present even inside the particles, copper It is effective in preventing oxidation.

The rapidly solidified powder produced by the water atomization method is often irregularly shaped, but it falls within the category of spherical particles of the present invention. Here, the silver concentration is A
g/(Ag+Cu) (atomic ratio). The copper alloy powder used in the present invention has an average particle size of 0.1 to 100 μm, but if it is less than 0.1 μm, contact resistance increases and conductivity is impaired. Moreover, when it exceeds 100 μm, suitability for screen printing is poor. Preferably 0.1 to 50 μm
, more preferably 0.5 to 30 μm.

[0013] The particle shape is preferably spherical, scaly, or a mixture thereof. When using scaly powder, a known method of mechanically flattening it can be used. Examples include methods such as stamp mill and pole mill. The copper alloy powder used in the present invention may contain Al, Zn, Sn, Pb, Si,
Mn, Bi, Mo, Cr, Ir, Nb, Sb, B, P,
Mg, Li, C, Na, Ba, Ti, In, Au, Pd
, Pt, Rh, Ru, Zr, Hf, Y, La and other metals, semimetals, and compounds thereof may be added,
In addition, at the same time as the powder used in the present invention, Al, Zn, Sn
, Pb, Si, Mn, Bi, Mo, Cr, Ir, Nb,
Sb, B, P, Mg, Li, C, Na, Ba, Ti, I
n, Au, Ag, Cu, Pd, Pt, Rh, Ru, Zr
, Hf, Y, La, metalloids, and powders of compounds thereof may be mixed.

The copper-based conductive paste of the present invention contains 5 to 100 parts by weight of the phenolic organic binder per 100 parts by weight of the copper alloy powder, but if the content is less than 5, the conductivity in the coating film will be reduced. There is not enough resin to keep the copper alloy powder bound, reducing conductivity and adhesion strength. Also, 1
If it exceeds 0.00 parts by weight, the amount of conductive copper alloy powder is insufficient and conductivity cannot be obtained. In addition, solderability is poor. Preferably it is 5 to 50 parts by weight. Furthermore, 5
~30 parts by weight is preferred.

Examples of the phenolic organic binder used in the present invention include novolac type phenolic resins, resol type phenolic resins, xylene resin-modified resol type resins, and rosin-modified phenolic resins. Among these, resol type and modified resol type resins are preferred. Also,
If necessary, known epoxy resin, phenolic OH
A mixture of modified epoxy resin, acrylic resin, urethane resin, polyester resin, amino resin, polyimide resin, and melamine resin can be used.

The copper-based conductive paste of the present invention contains 0.00 parts of titanium coupling agent per 100 parts by weight of copper alloy powder.
001 to 3 parts by weight, and 0.01 to 50 parts by weight of an additive capable of removing copper oxide. It has the function of reducing or eluting and removing copper oxide from the particle surface. That is, the conductive mechanism of the copper-based conductive paste of the present invention is that it has conductivity through the contact points between powders, and therefore the characteristics of the surface of each particle are important. The copper alloy powder used in the present invention has silver concentrated on the particle surface, but by removing or reducing the copper oxide present on the particle surface, sufficient silver contact is ensured, and it can be used at high temperatures or high humidity. This shows long-term stability regarding the oxidation resistance of the particle surface.

[0017] If the amount of the additive is less than 0.01 part by weight, sufficient conductivity cannot be obtained, and if it exceeds 50 parts by weight, the additive may be adsorbed onto the particle surface. conductivity. Therefore, it is preferable to add the necessary amount to the amount of copper oxide present on the particle surface, and 0.1 to 30
Parts by weight are preferred, and more preferably 1 to 15 parts by weight.

The additive capable of removing the copper oxide is selected from fatty acids, dicarboxylic acids, oxycarboxylic acids and their metal salts, phenolic compounds, metal chelate forming agents, higher aliphatic amines, rosin, anthracene and derivatives thereof. One or more types are mentioned. Fatty acids include saturated fatty acids (e.g. acetic acid, propionic acid, butyric acid, valeric acid,
caproic acid, enanthic acid, caprylic acid, capric acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, etc.) and unsaturated fatty acids (e.g.
Acrylic acid, oleic acid, elaidic acid, cetoleic acid, erucic acid, brassic acid, sorbic acid, linoleic acid,
arachidonic acid, stearolic acid, etc.), and metal salts thereof. At this time, in order to produce a coating film with high adhesion, metal salts of higher fatty acids or fatty acids having 13 or less carbon atoms and metal salts thereof are preferable.

Examples of dicarboxylic acids include aliphatic saturated dicarboxylic acids (for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, etc.) and aliphatic unsaturated dicarboxylic acids. acids (e.g. maleic acid, fumaric acid, etc.), aromatic dicarboxylic acids (e.g. phthalic acid, isophthalic acid, terephthalic acid, etc.) and their metal salts (e.g. copper, iron, magnesium,
(manganese, silver, etc.) and anhydrides.

[0020] The oxycarboxylic acids include aliphatic oxycarboxylic acids (for example, glycolic acid, lactic acid, hydroacrylic acid, α-oxybutyric acid, glyceric acid, tartronic acid, tartaric acid, citric acid, etc.) and aromatic oxycarboxylic acids. (For example, salicylic acid, p-, m-oxybenzoic acid, mandelic acid, tropic acid, oxyphenylacetic acid, resorcinic acid, orceric acid, gentisic acid, protocatechuic acid, caffeic acid, umbelic acid, etc.) and their metal salts. . Examples of metals include copper, manganese, silver, iron, magnesium, and cobalt. Preferably mandelic acid, citric acid, salicylic acid, resorcinic acid, p-,
m-oxybenzoic acid.

[0021] As the phenolic compound, monovalent, divalent,
Examples include trihydric phenols and their derivatives (e.g.
Phenol, cresol, 3,5-xylenol, carvacrol, thymol, naphthol, catechol, resorcinol, hydroquinone, methylhydroquinone, tert-
butylhydroquinone, chlorohydroquinone, phenylhydroquinone, 1, 2, 4 benzenetriol, pyrogallol, phloroglucin, etc.).

Examples of metal chelate forming agents include amino alcohols (such as ethanolamine, diethanolamine, triethanolamine and derivatives thereof), amine compounds such as ethylenediamine, triethylenediamine and toluethylenetetramine, acetylacetone and its derivatives (such as trifluoroacetylacetone, hexafluoroacetylacetone, benzoylacetone, etc.).

The higher fatty acid amine is preferably one having 8 to 22 carbon atoms and is soluble in a solvent. For example, the saturated monoamine includes stearylamine, palmitylamine, behenylamine, cetylamine, octylamine, decylamine, Examples of unsaturated monoamines such as laurylamine include oleylamine, and examples of diamines include stearylamine propylene diamine and oleylpropylene diamine. Examples of anthracene and its derivatives include anthracenecarboxylic acid. Examples of the rosin include modified rosins such as partially hydrogenated rosin, fully hydrogenated rosin, esterified rosin, maleated rosin, disproportionated rosin, and polymerized rosin.

Among them, dicarboxylic acids, metal chelate forming agents, and phenol compounds are preferred. Regarding the solderability, which is a feature of the copper-based conductive paste of the present invention, the use of a titanium coupling agent improves the dispersibility of the particles in the coating film, and the surface of the cured film is coated with a conductive copper alloy. The powder becomes easier to disperse. Furthermore, since the conductive copper alloy powder particles used in the present invention have a high concentration of silver on the surface, solderability can be improved.

The titanium coupling agent that can be used in the present invention has a hydrophilic group or a lipophilic group,
Monoalkoxy type (isopropoxy group), chelate type (
Examples include those having oxyacetic acid residues and those having ethylene glycol residues), and coordinated types (those having a phosphite ester added to a tetraalkyl titanate). For example, isopropyltriisostearoyltitanate, isopropyltri(dioctylpyrophosphate)titanate, isopropyltri(N-aminoethyl-aminoethyl)titanate, tetraoctylbis(ditridecylphosphite)titanate, tetra(2,2-diallyloxymethyl -1-butyl)bis(
ditridecyl) phosphite titanate, bis(dioctyl pyrophosphate) oxyacetate titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyltrioctanoyl titanate, isopropyl dimethacrylic isostearoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl isostearolyl titanate diacrylic titanate, isopropyl tri(dioctyl phosphate) titanate, isopropyl tricumylphenyl titanate, tetroisopropylbis(dioctyl phosphate)
There's titanate. Among them, those having a monoalkoxy group,
Carboxylic acid ester type titanium coupling agents are preferred. For example, isopropyl triisostearoyl titanate and isopropyl trioctanyl titanate are preferred.

The amount used is 0.001 to 3 parts by weight, but if it exceeds 3 parts by weight, the conductivity will be impaired. Moreover, if it is less than 0.001, sufficient solderability cannot be obtained. Preferably 0.01 to 1 part by weight, further
0.01 to 0.5 parts by weight is preferred. On the other hand, as explained in the conventional technology, in the paste using known copper powder, even if the surface is treated with an oxide remover, the new contact is a copper-copper contact. If exposed to high temperature or high humidity for a long period of time, the surface will be oxidized and the conductivity will gradually deteriorate, resulting in a decrease in solderability.

Furthermore, when the additive of the present invention is added to a known paste using silver, the additive is instead adsorbed onto the silver surface, causing an increase in contact resistance and impairing conductivity. The copper-based conductive paste of the present invention provides a conductive paste that has excellent conductivity and migration resistance, and is solderable. Needless to say, additives such as a chemical agent, a leveling agent, an antifoaming agent, a silane coupling agent, an aluminum coupling agent, a zirconium coupling agent, etc. may be added.

The method for curing the copper-based conductive paste of the present invention includes a box-type hot air convection oven, a continuous hot-air oven, a muffle-type heating furnace, a near-infrared oven, a far-infrared oven, a vapor phase heating oven, or an EB curing method. A known method such as the following is used. In addition, the temperature for drying or thermosetting is preferably a temperature that does not adversely affect the characteristics of the substrate. For example,
Preferably from room temperature to 300°C, and more preferably from room temperature to 250°C.
°C is preferred. The curing atmosphere may be in air (oxygen concentration of about 20%), but an atmosphere with low or no oxygen concentration is preferred.

When using the copper-based conductive paste of the present invention, a solvent can be used if necessary. The amount of solvent is preferably 0 to 100 parts by weight based on a total of 100 parts by weight of the copper alloy powder and the phenolic organic binder. The solvent that can be used in the present invention varies depending on the resin used for the organic binder, but any known solvent may be used. For example, aromatics such as toluene and xylene, ketones such as methyl ethyl ketone and methyl isobutyl ketone, esters such as butyl acetate and ethyl acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and ethylene glycol. Dimethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monoallyl ether, ethylene glycol decyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monoisopropyl ether and its acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, diethylene glycol decyl ether, diethylene glycol monohexyl ether and its acetate, diethylene glycol methyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether,
Triethylene glycol monomethyl ether, triethylene glycol decyl ether, triethylene glycol mono-n-butyl ether and its acetate, alcohols such as triethylene glycol dimethyl ether, α-tenopenol, β-terpenol, isopropanol, butanol, phenol, chlorophenol, etc. Phenols dioxane, dimethylacetamide,
Those containing one or more selected from dimethylformamide, N-methylpyrrolidone, and γ-lactone are preferred.

When using the solderable copper-based conductive paste of the present invention, screen printing, spray method, brush method, bar coating method, doctor blade method, flexure printing, microdispenser method, gravure printing method, offset printing method, etc. Known printing and coating methods such as a printing method, a pen writing method, and a dipping method can be used. Among these, screen printing is preferred. When using the screen printing method, it depends on the pattern, but for example, 5
0 to 400 mesh is preferred, and 150 to 400 mesh is more preferred. Among them, 200 mesh or more is preferable for printing fine lines.

[0031] As the substrate on which the copper-based conductive paste of the present invention is printed, any known substrate can be used, but for example,
Glass epoxy resin substrate, paper phenolic resin substrate, paper epoxy resin substrate, polyimide substrate, polyester resin substrate, BT resin resin substrate, polysulfone resin substrate, polyethersulfone resin substrate, polyetherimide resin substrate, resin, polybutadiene resin substrate , hard plates and flexible glass polyimide resin substrates, or ceramic substrates such as alumina substrates and aluminum nitride substrates,
Can be applied to metal substrates such as aluminum and stainless steel. For example, when used for flexible substrates such as polyimide and polyester, copper-based conductive pastes that use a binder mainly composed of vinyl resin (e.g., vinyl chloride-vinyl acetate copolymer), saturated polyester, or polyurethane resin are used. is preferred.

When the copper-based conductive paste of the present invention is used as an electromagnetic shielding paste, it is preferable to print it on the surface of a printed circuit board for shielding. It can also be used by coating plastic bodies for word processors, computer equipment housings, card readers, measuring instruments, car phones, keyboards, medical instruments, musical instruments, CRTs, and the like.

When the copper-based conductive paste of the present invention is used as a conductive adhesive, for example, an adhesive for taking out lead wires from the electrodes of a crystal resonator, an adhesive between molded carbon and metal, and a liquid crystal adhesive. (LCD) Conductive adhesive between glass inside glass, adhesive to lead frames and substrates (especially IC
It can be applied to materials such as die bonding), CdS parts of photoconductive elements, potentiometer lead wire adhesives, circuit repair adhesives, and materials that cannot be exposed to high temperatures.

[0034] When used as a through-hole, the above-described copper-based conductive paste is embedded in the through-hole made by punching or the like in a printed wiring board. In this case, it is preferable to use screen printing or flexure printing, for example, and at this time, it is preferable to reduce the pressure to some extent from the back side of the hole so that the paste can be sufficiently filled in the hole.

Further, as an electrode, it can be used by coating (for example, by dipping the electrode portion into a paste) as an electrode for a capacitor. The silver concentration on the surface and near the surface was measured using XPS (X-ray electron spectroscopy analyzer: trade name: XSAM800, manufactured by KRATOS). First, a conductive carbon double-sided adhesive tape was attached to the sample stand, and the sample powder was gently attached to completely cover the double-sided tape without deforming the sample powder. Measurement of silver concentration is based on magnesium Kα
A wire (voltage 12kv, current 10mA) is incident, the photoelectron extraction angle is 90 degrees with respect to the sample surface, and the room pressure is 10-8.
I went with torr. Etching was performed using an argon ion gun at an acceleration voltage of 3 keV, an incident angle of the argon ion beam on the sample surface of 45 degrees, and a room pressure of 10-7 torr.
I did it in minutes.

To measure the silver concentration, the measurement and etching were repeated five times, and the average value of the first two measurements was taken as the silver concentration on the surface. The average silver concentration was measured by dissolving the sample in concentrated nitric acid and using an ICP (high frequency inductively coupled plasma emission spectrometer manufactured by Seiko Electronics Co., Ltd.). The average particle size was measured using a laser diffraction particle size analyzer (Shimadzu Corporation).
Co., Ltd., trade name SALD1100) was used. As a measurement method, the powder was sufficiently dispersed in an ethylene glycol solution (powder concentration 1 to 20 x 10-3 g/cc) and measured five times. The average value of the volume cumulative average value measured five times was taken as the average particle diameter.

The conductivity of the coating film made of the copper-based conductive paste was measured using a four-terminal method. In addition, in the migration test, a 10V DC voltage was applied between two films coated at 1 mm intervals, and a 0.2 ml water drop was dropped between the films to measure the leakage current, and the current value was 100 μA. The migration time was defined as the time exceeding . As a durability test, changes in conductivity after being left at 60° C. and 90% humidity (humidity resistance test) were measured.

[0038] The adhesion of the film was determined using a grid test. (1c
100 squares were made at 1 mm intervals on a m x 1 cm pad, and the number of squares remaining after peeling off with tape was measured. ) Solderability is determined by applying flux (product name #36 manufactured by Multicore Co., Ltd.) onto the coating film (2cm x 2cm pad).
6) was applied in the required amount and immersed in a solder bath (230° C., eutectic solder) for 3 seconds to measure the wetted area. The wetted area was rated as good by 90% or more.

[0039] Also, the adhesion strength of soldering is 2mm x 2
Solder a 0.8mm diameter wire to the mm pad,
The strength at the time of peeling when pulled at a speed of 2 cm/sec was measured, and a value of 500 g/4 mm 2 or more was considered good. The electromagnetic shielding characteristics were measured at 100kHz using a waveguide, a spectroanalyzer, and a tracking generator.
The shielding effect was measured from z to 2 GHz.

[0040] The conductivity properties for through holes are 1.5,
Screen printing (320
Printing was carried out using a mesh) under reduced pressure so that the holes were completely filled. After printing, each composition was cured using a method appropriate to its composition. Further, if necessary, the cured product made of the composition of the present invention can be trimmed by a laser or other methods.

The present invention will be specifically explained below using Examples and Comparative Examples.

[0042]

[Example] An example of producing copper alloy powder will be shown as a reference example.

[0043]

[Reference example 1] 315.595g of copper particles and 3.23g of silver particles
7 g was melted in a graphite crucible using high frequency induction heating. The atmosphere was 99.9% or more nitrogen. 1720
After heating to .degree. C., the melt falling from the tip of the crucible was mattomized with 99.9% or more nitrogen gas at a pressure of 15 k/G at a gas/liquid mass velocity ratio of 1.5. The linear velocity of the gas at the impact location was 100 m/sec. The obtained powder had an average particle size of 18 μm. When measured by XPS, the silver concentration on the surface was 0.06, 0.04, 0.03, 0.0 lower than that on the surface.
2, 0.01, the surface silver concentration is 0.05, and
The average silver concentration was x=0.006 (y=0.994), and the surface silver concentration was 7.5 times the average silver concentration.

[0044]

[Reference example 2] 314.325g of copper particles and 5.39g of silver particles
5 g was melted under high frequency induction heating in the same manner as in Reference Example 1. After melting to 1700° C., nitrogen gas (99.7% or more) at a gas pressure of 20 k/G was atomized to the melt jetted from the nozzle tip at a gas/liquid mass velocity ratio of 1.5. At this time, the linear velocity of the gas at the gas nozzle outlet is 120 m
/second. The obtained powder had an average particle size of 17 μm. The silver concentration on the surface is 0.07, 0.06, 0.0.
05, 0.04, and 0.03, and the silver concentration on the surface is 0.05, 0.04, and 0.03.
065, and the average silver concentration is x=0.01 (y=0.
99), and the surface silver concentration was 6.5 times the average silver concentration.

[0045]

[Reference Example 3] 285.75g of copper particles and 53.95g of silver particles
g was similarly melted in a graphite crucible. After melting to 1570℃, the melt is jetted out from the tip of the crucible, and at the same time the pressure is 1
5k/G nitrogen gas (>99.9%) was atomized at a gas/liquid mass velocity ratio of 1.7. The linear velocity of the gas at the exit of the gas nozzle at this time was 100 m/sec, and the average particle size of the obtained powder was 18 μm. Also, the silver concentration on the surface is 0.74, 0.65, 0.55, 0.5, 0.
48, the surface silver concentration is 0.695, and the average silver concentration is x = 0.1 (y = 0.9), and the surface silver concentration is 6.85 times the average silver concentration. there were.

[0046]

[Reference Example 4] 254 g of copper particles and 107.9 g of silver particles were similarly melted by high-frequency induction heating. After heating to 1850°C, nitrogen gas (pressure 17k/G, 99°C
．． 9% or more) was atomized at a gas/liquid mass velocity ratio of 2. At this time, the linear velocity of the gas at the gas nozzle outlet is 80 m/
It was seconds. The obtained powder had an average particle size of 20 μm. The silver concentration on the surface is 0.8, 0.75, 0.7,
0.65, 0.6, the surface silver concentration is 0.775, and the average silver concentration is x = 0.2 (y = 0.8)
The surface silver concentration was 3.85 times the average silver concentration.

[0047]

[Reference Example 5] 206.375g of copper particles and 188g of silver particles.
825 g was similarly melted to 1500° C. by high frequency induction heating. Furthermore, the melt was spouted from the tip of the crucible into an inert atmosphere (nitrogen). At the same time as blowing out, gas pressure 15k/G
of nitrogen gas (99.9% or more) was atomized to the melt at a gas/liquid mass velocity ratio of 1.8. The gas linear velocity at this time was 90 m/sec. The average particle size of the obtained powder is
It was 17 μm. The silver concentration on the surface is 0.88, 0.8
, 0.75, 0.7, and 0.65, and the surface silver concentration was 0.84. Also, the average silver concentration is x=0.35
(y=0.65), which was 2.4 times the average silver concentration.

[0048]

[Reference Example 6] 127 g of copper particles and 323.7 g of silver particles were similarly melted to 1600°C. The melt was ejected from the tip of the crucible into an inert gas atmosphere (nitrogen). Simultaneously with the ejection, nitrogen gas (99.9% or more) at a gas pressure of 30 k/G was atomized to the melt at a gas/liquid mass velocity ratio of 0.8. The linear velocity of the gas at this time is 150 at the gas nozzle exit.
m/sec, and the obtained powder had an average particle size of 16 μm. The average silver concentration of the obtained powder was x=0.6 (y=0
．． 4).

[0049]

[Reference Example 7] 63.5 g of copper particles and 431.6 g of silver particles were similarly melted to 1720° C. by high-frequency induction heating. The melt was injected into the inert atmosphere from the tip of the crucible. Simultaneously with the ejection, the melt was atomized with nitrogen gas (99.9% or more) at a gas pressure of 40 k/G at a gas/liquid mass velocity ratio of 2.1. The gas linear velocity at this time was 160 m/sec. The average particle size of the obtained powder was 14 μm. Also,
The average silver concentration was x=0.8 (y=0.2).

[0050]

[Reference Example 8] 9.525g of copper particles and 523.31g of silver particles
5 g was similarly heated and melted to 1800°C using high frequency induction heating. The melt was ejected from the tip of the crucible, and at the same time, nitrogen gas (99.9% or more) at a gas pressure of 50 k/G was atomized to the melt at a gas/liquid mass velocity ratio of 2.3. The linear velocity of the gas at this time was 180 m/sec at the gas nozzle exit. The average particle size of the obtained powder was 13 μm.
Met. The average silver concentration is x=0.97 (y=0.03
)Met.

[0051]

[Example 1] x=0.006, y=0.99 obtained in Reference Example 1
Particles of 15 μm or less among the powders in No. 4 (average particle size 7 μm)

10g alkylated phenolic resin

0.2g linoleic acid copper salt

0.1g isopropyl tri(N
-amino aminoethyl) titanate 0.01g
Butyl carbitol
3g
were thoroughly mixed and applied onto a glass epoxy resin substrate using screen printing (250 mesh). 1 coating film
It was cured by heating at 70°C for 30 minutes. The volume resistivity of the resulting coating film was 1×10 −4 Ω·cm, and the migration time was 295 seconds, which was comparable to that of copper. Furthermore, when we did a humidity resistance test, (60℃, 90% humidity)
The rate of change after standing for 1000 hours was 20%. Also,
I did a grid test and it was 100/100. In the solderability test, a 20 mm x 20 mm square pattern was screen printed, and flux (product name #36 manufactured by Multicore Co., Ltd., product name
After coating 6), the coated area was measured by immersing the sample in a eutectic solder bath maintained at 230° C. for 3 seconds. The painted area is 95
% or more. In addition, the soldering adhesion strength is 1kg/
It was 4mm2.

[0052]

[Example 2] Among the powders with x = 0.1 and y = 0.9 obtained in Reference Example 3, powder with a diameter of 15 μm or less

10g resol type phenolic resin
0.8g Isopropyl triisostearoyl titanate
0.015g triethanolamine
0.3g Butyl Cellosolve
4 g were thoroughly mixed and applied onto a glass epoxy resin substrate using screen printing. The coating film was heat cured in air at 150°C for 30 minutes. The volume resistivity of the obtained coating film was 8×10-5Ω・
cm, and as a result of the migration test, 290 seconds,
Further, as a result of a humidity resistance test, the rate of change was 10% even after being left for 1000 hours. The result of the grid test was 100/100. A solderability test was conducted in the same manner as in Example 1, and the wetted area was 95% or more. The solder adhesion was 1.3 kg/4 mm2.

[0053]

[Example 3] Among the powders with X = 0.2 and y = 0.8 obtained in Reference Example 4, powder with a diameter of 15 μm or less

10g Novolac type phenolic resin
1.7g mandelic acid
0.
01g pyrocatechol

0.05g Bis(dioctylpyrophosphate)oxyacetate titanate


0.005g ethyl acetate

2g ethyl cellosolve

3 g were mixed thoroughly and applied onto a glass epoxy resin substrate. The coating film was heat cured in air at 155°C for 20 minutes. The volume resistivity of the cured coating film was 6×10 −5 Ω·cm, and the migration time was 285 seconds. Further, as a result of a humidity resistance test, the rate of change after standing for 1000 hours was within 1%. Moreover, the result of the grid test was 100/100. As a result of the solderability test, the wetted area was 92%. In addition, the soldering adhesion strength is 1.6kg/4mm2
Met.

[0054]

[Example 4] Among the powders with x = 0.35 and y = 0.65 obtained in Reference Example 5, the powder is 10 μm or less

10g resol type xylene resin
0.7g OH terminal modified epoxy resin
0.3g Butylated melamine resin
0.2g diisopropylbis(dioctylpyrophosphate) titanate

0.017g ethanolamine
0.1g Butyl carbitol acetate
3 g were thoroughly mixed and screen printed onto an alumina substrate. Paint film 180
C. for 30 minutes. The volume resistivity of the obtained cured film was 2×10 −4 Ω·cm, and the migration time was 260 seconds. Furthermore, the rate of change in the humidity resistance test is 1
It was within %. The result of the grid test was 100/100. When the solderability was measured in the same way, it was 9.
A wetted area of 5% or more was observed. Further, the soldering adhesion strength was 1.3 kg/4 mm2.

[0055]

[Example 5] Among the powders with x=0.6 and y=0.4 obtained in Reference Example 6, the powder is 10 μm or less

10g resol type xylene modified phenolic resin
0.8g epoxy acrylate
0.4g pyrocatechol
0.1g Bis(dioctylpyrophosphate) ethylene titanate 0.02g MEK

1 g was thoroughly mixed, applied onto a polysulfone resin substrate, and cured by heating at 180° C. for 30 minutes. The volume resistivity of the obtained coating film was 8×10−
The resistance was 5Ω·cm, and the migration time was 230 seconds. Further, as a result of a humidity resistance test, the rate of change after being left for 1000 hours was within 1%. Moreover, the result of the grid test was 100/100. When the solderability was measured in the same manner, the wetted area was 90%. Also,
The soldering adhesion was 800 g/4 mm2.

[0056]

[Example 6] Among the powders with x = 0.8 and y = 0.2 obtained in Reference Example 7, the powder is 10 μm or less

10g resol type phenolic resin
1.5g sebacic acid
0
．． 1g Tetra(2,2-diallyloxymethyl-1
-butyl)bis(ditridecyl)phosphite titanate
0.005g ethyl cellosolve
4 g were thoroughly mixed and applied onto a polyimide resin flexible substrate. The coating film was cured by heating at 190° C. for 4 minutes in a far-infrared oven. The volume resistivity of the cured film was 6×10 −5 Ω·cm. The migration test result was 180 seconds. Furthermore, as a result of the humidity resistance test, the rate of change after 1000 hours was within 1%. Also, the result of the grid test is 100/100.
Met. When the solderability test was conducted in the same manner and evaluated, the wetted area was 95% or more. Further, the soldering adhesion strength was 0.7 kg/4 mm2.

[0057]

[Example 7] Among the powders with x = 0.97 and y = 0.03 obtained in Reference Example 8, powder with a diameter of 15 μm or less

10g resol type phenolic resin
1.8g Isopropyl triisostearoyl titanate
0.0003g L-ascorbic acid
0.1g stearylamine
0.1g Butyl carbitol
3g were thoroughly mixed. Tantalum capacitor 3mm x 3mm x 2
Only one side of the sample was immersed into the paste having the above composition. The paste was similarly dipped onto the opposite side of the capacitor. Further, the electrode was cured by heating at 180° C. for 30 minutes in nitrogen.

An electrode with a film thickness of 0.8 mm was obtained. The volume resistivity was 5×10 −4 Ω·cm. As a result of the humidity resistance test, the rate of change after standing for 1000 hours was within 2%. Furthermore, when the solderability was evaluated, the wetted area was 95% or more. Solder adhesion strength is 1.4kg/4mm2
Met.

[0059]

[Example 8] Among the powders with x = 0.01 and y = 0.99 obtained in Reference Example 2, the powder is 10 μm or less

10g resol type phenolic resin
2g triethanolamine
0.3g Butyl carbitol
2g diisopropyl bis(joctylpyrohaphate) titanate

Thoroughly mix 0.1 g, screen print onto a polyimide resin base as electrodes on both ends of a carbon resistor that has already been printed and cured, and then apply 2 g in nitrogen.
It was heated and cured at 00°C for 10 minutes. When the cured film was measured, no change was observed in the resistance value of the resistor, confirming that sufficient ohmic contact was obtained. Furthermore, when the solderability was measured in the same manner, a wetted area of 95% or more was confirmed. Soldering adhesion strength is 0.9k
g/4mm2.

[0060]

[Reference Example 9] Copper particles 317.46825g, silver particles 0.
05395g was heated to 170g by high frequency induction heating in a graphite crucible.
The mixture was heated and melted to 0°C. The melt was spouted into an inert atmosphere (nitrogen) through a nozzle attached to the tip of the crucible. Simultaneously with the ejection, the melt was atomized with nitrogen (99.9% or more) at a gas pressure of 20 k/G at a gas/liquid mass velocity ratio of 1.7. The gas linear velocity at this time was 100 m/sec. The average particle size of the obtained powder was 19 μm. The average silver concentration at this time is x=0.0001 (y=0.999
9).

[0061]

[Reference Example 10] Copper particles 0.03175g, silver particles 539
．． 446 g was similarly melted to 1780° C. by high frequency induction heating. While spouting the melt, the gas pressure is 20k/G.
of nitrogen gas (99.9% or more) was atomized to the melt at a gas/liquid mass velocity ratio of 2. The gas linear velocity at this time was 100 m/sec. The average particle size of the obtained powder was 18 μm. The average silver concentration is x=0.999
9 (y=0.0001).

[0062]

[Reference Example 11] Copper particles 285.75g, silver particles 53.9g
5 g was similarly heated and melted to 1600°C. At the same time as blowing out the melt, the gas pressure is 20k/G (oxygen 10% nitrogen 90%
gas/liquid mass velocity ratio 2
It was atomized. The gas linear velocity at this time is 100 m/
It was seconds. When the surface silver concentration of the obtained powder was measured, it was 0.08, 0.09, 0.1, 0.11,
The silver concentration on the surface is lower at 0.13, the silver concentration on the surface is 0.085, and the average silver concentration is x=0.1, y=0.
9, and the surface silver concentration was 0.85 times the average silver concentration.

[0063]

[Comparative Example 1] x=0.0001, y=0.9 produced in Reference Example 9
Powder of 10μm or less among 999 powders

10g resol type phenolic resin
3g linoleic acid copper salt

0.01g MEK

3
g Isopropyl triisostearoyl titanate
0.001 g was thoroughly mixed and spray coated onto a paper phenolic resin substrate. The coating film was cured by heating at 150° C. for 15 minutes. The volume resistivity of the coating film after curing was as high as 2×10 −2 Ω·cm. Further, the result of the grid test was 100/100, but the result of the humidity resistance test showed that the rate of change after being left for 1000 hours was as large as 300%. Furthermore, when the solderability was measured, the solder wetted area was as small as 5%.

[0064]

[Comparative Example 2] x=0.9999, y=0. produced in Reference Example 10.
Powder of 10μm or less among 0001 powders

10g resol type xylene resin
1.2g Isopropyl triisostearoyl titanate
0.005g triethanolamine

0.005g Butyl carbitol

2g were thoroughly mixed and applied onto a glass epoxy resin substrate. The volume resistivity of the coating film is 5
×10-5Ω・cm, humidity resistance test result: 1000
Even if you leave it for a long time, the rate of change is 10%, and the grid test is also 100.
/100, but the migration time was as short as 15 seconds, making it easy to migrate. Further, as a result of the solderability test, there was significant solder erosion. The solder adhesion was 0.2 kg/4 mm2.

[0065]

[Comparative Example 3] x=0.01, y=0.99 produced in Reference Example 10
Powder of 10μm or less among the powders of

10g resol type phenolic resin
20g isopropyl isostearoyl titanate
0.001g triethanolamine

0.05g ethyl cellosolve

20g were thoroughly mixed and applied onto a glass epoxy resin substrate. Paint film for 30 minutes, 15
It was cured by heating at 0°C. The volume resistivity of the obtained cured film is
It was as high as 1×10Ω・cm. Further, as a result of the humidity resistance test, the rate of change after being left for 1000 hours was as large as 200%. The result of the grid test was 100/100. Also,
As a result of the soldering test, the wetted area was 1%. The solder adhesion was 0.01 kg/4 mm2.

[0066]

[Comparative Example 4] Powder obtained in Reference Example 11 x=0.1, y=0.9
Powder of 10μm or less

10g resol type phenolic resin
0.1g pyrocatechol
0.2
g Bis(dioctylpyrophosphate)oxyacetate titanate

0.0005g
Butyl carbitol
4g
were mixed and screen printed onto a glass epoxy resin substrate. The coating film was cured by heating at 140° C. for 30 minutes. The volume resistivity of the cured film was as high as 2×10 −2 Ω·cm. In addition, as a result of the humidity resistance test, the rate of change after being left for 1000 hours was as follows:
It was as large as 250%. Moreover, the film was easy to peel off. The grid test result was 3/100, which was very poor.

[0067]

[Comparative Example 5] Among the powders with x=0.01 and y=0.99 produced in Reference Example 2, the powder is 15 μm or less

10g resol type phenolic resin
1g pyrocatechol

0.1g Isopropylisostearoyl titanate
0.00001g ethyl cellosolve

2 g were mixed and screen printed onto a glass epoxy resin substrate. Paint film at 150℃, 30
Cured by heating in air for minutes. The volume resistivity of the cured film is 5×
Although the solderability was 10 −4 Ω·cm, the wetted area was only 50%.

[0068]

[Comparative Example 6] x=0.01g, y=0.99 produced in Reference Example 2
Powder of 15μm or less among the powders of

10g resol type phenolic resin
2g triethanolamine
10g isopropyl isostearoyl titanate
0.001g Butyl carbitol acetate
2 g of the dispersed composition was similarly screen printed onto a glass epoxy resin substrate. Paint film 160
C. for 20 minutes. The volume resistivity of the obtained cured film was as high as 2×10 −2 Ω·cm. In addition, as a result of the humidity resistance test, the rate of change after being left for 1000 hours was 200%.
It was big. Also, the result of the grid test was 30/100, which was poor. Further, as a result of a soldering test, the wetted area was 10% or less.

[0069]

[Comparative Example 7] 10 g of copper powder plated with 90% silver and having an average particle size of 10 μm Resol type phenolic resin

2g triethanolamine

0.8g Isopropylbis(octylpyrophosphate) titanate

0.
001g Butyl Cellosolve

2 g were mixed and screen printed onto a glass epoxy resin substrate. It was cured by heating at 150°C for 20 minutes. The volume resistivity of the cured film was 3×10 −3 Ω·cm, and the migration test results showed that it was as fast as 15 seconds. Further, as a result of the soldering test, there was significant solder erosion. The soldering adhesion was 0.4 kg/4 mm2.

[0070]

[Comparative Example 8] Among the powders with x=0.01 and y=0.99 produced in Reference Example 2, the powder is 15 μm or less

10g resol type phenolic resin
2g triethanolamine
0.1g Isopropylbis(octylpyrophosphate) titanate


10g butyl carbitol acetate

The resulting composition was similarly screen printed onto a glass epoxy resin substrate. The coating film was cured by heating at 180° C. for 30 minutes. The volume resistivity of the obtained coating film was as high as 2×10 −2 Ω·cm. Further, as a result of a soldering test, the rate of change after being left for 1000 hours was as large as 200%. Further, as a result of the soldering test, the solder was hardly attached at 3%.

[0071]

[Effects of the Invention] The present invention is a copper-based conductive paste that has excellent conductivity, oxidation resistance, and migration resistance, and can be soldered. It exhibits excellent properties as a conductive paste, an electrode paste for capacitors, and a paste for through holes.

Claims (2)

[Claims] Claim 1: General formula AgxCuy (where 0.0
01≦x≦0.999, 0.001≦y≦0.999,
x + y = 1, atomic ratio) 100 parts by weight of copper alloy powder and 5 to 100 parts by weight of phenolic organic binder,
A solderable copper-based conductive paste comprising 0.001 to 3 parts by weight of a titanium coupling agent and 0.01 to 100 parts by weight of an additive capable of removing copper oxides. Claim 2: Copper alloy powder represented by the general formula AgxCuy is 0.001≦x≦0.4, 0.6≦y≦0.99
9 (atomic ratio), the silver concentration on the surface of the copper alloy powder particle is higher than the average silver concentration, and there is a region near the surface where the silver concentration increases from the inside toward the surface. Item 1. Solderable copper-based conductive paste according to Item 1.