CN103187116A - Conductive paste, substrate with conductive film and manufacturing method thereof - Google Patents

Abstract

The invention aims to provide conductive paste, a substrate with a conductive film and a manufacturing method thereof. The conductive paste can form the conductive film with small size, low resistance and good thermo-cycling durability. The conductive paste includes copper particles (A), thermoset resin (B) and aromatic compounds (C) whose molecules provided with phenolic hydroxyl and at least one perssad containing ester bond. The conductive paste also can include carboxylate (D) of high-molecular compound whose molecules provided with amino. The conductive paste can be pasted on the substrate and heat under a temperature of 150 DEG C for solidifying, so that the conductive film is formed.

Description

Base material and the manufacture method thereof of conductive paste, band conducting film

Technical field

The present invention relates to conductive paste, use the manufacture method of the base material of the base material of band conducting film of conductive paste and band conducting film.

Background technology

All the time, the known method of in the formation of wiring conductors such as electronic unit, printed circuit board (PCB) (printed base plate), using conductive paste.Wherein, for example, the manufacturing of printed base plate is following to be carried out: after on the insulating properties base material that is formed by glass, pottery etc. conductive paste coating being the pattern form of expectation, be heated to 150 ℃ with the roasting that comes up, form wiring pattern, thereby carry out.

As conductive paste, from guaranteeing the viewpoint of high conductivity, mainly being suitable for silver (Ag) is the silver-colored paste of principal component.Yet, when silver-colored paste is switched under hot and humid environment, the silver atoms ionization takes place easily and by electric field attracts and mobile ion migration (electro-deposition of silver).When the ion migration takes place in wiring pattern, the worry that exists the reliability that produces unfavorable condition such as be short-circuited between the wiring, circuit board to reduce.

Therefore, the viewpoint from the reliability that improves electronic equipment, circuit board has proposed to use the copper paste to replace the technology of silver-colored paste as conductive paste.The connection reliability that the copper paste can improve circuit owing to be difficult for transport phenomena takes place.

Yet, the usually easy oxidation of copper, on the base material with the pattern form of conductive paste coating for expectation after, when in atmosphere, heating, easily by with atmosphere in the reaction of moisture, oxygen etc. produce cupric oxide.Therefore, the copper paste is heating and curing and problem that the conducting film that forms exists easily the influence specific insulation because of the oxidation overlay film to uprise.

In addition, in environmental reliability test (for example, thermal cycling test etc.), during by heating in atmosphere with atmosphere in the reaction of moisture, oxygen etc. cause the copper oxidation, existence can't obtain the problem as the sufficient durability of the conductor that connects up.

In order to address this is that, proposed to be compounded in by the manufacturing of wet type reducing process the technology of the copper powders may in the copper paste, but the wiring conductor is not improved fully with the rising of the specific insulation in the conductive paste.

The wiring conductor with the conducting mechanism in the copper paste based on: by the cure shrinkage as the thermosetting resin of binding agent, the crimping each other of copper particle, electric current flows by the contact of copper particle, therefore, because the state of oxidation of copper particle surface, the compressive state of resin glue, conductivity is subjected to very big influence.

Improvement about the state of oxidation of copper particle surface, compounding catechol, resorcinol, the such material with reduction (hereinafter referred to as reducing agent) of hydroquinones in the copper paste have been proposed at present, thereby prevent the technology (for example, with reference to patent documentation 1) of the oxidation of copper particle surface.

By the conducting mechanism in the aforementioned copper paste obviously as can be seen, can cause connecting resistance as the surface film oxide of insulant and increase, therefore need to use reducing agent to suppress the oxidation of copper particle surface.Yet, in the patent documentation 1 method of record have the durability be difficult to improve to cold cycling, the big problem of climbing of the specific insulation of conducting film after cold cycling that obtained by this copper paste.

The technology (for example, with reference to patent documentation 2) of the oxidation of the copper particle surface when handling fine copper powder with dibutyl hydroxy toluene and prevent in atmosphere heat drying has been proposed in addition.

Yet the paste of record is high temperature (480 ~ 600 ℃) roasting paste in the patent documentation 2, can not be as the printed circuit board (PCB) that solidifies under the low temperature below 150 ℃.In addition, be difficult to solve the problem to the raising of the durability of aforementioned cold cycling that when curing conductive paste below 150 ℃, produces.

The prior art document

Patent documentation

Patent documentation 1: Japanese kokai publication hei 8-73780 communique

Patent documentation 2: TOHKEMY 2009-146890 communique

Summary of the invention

The problem that invention will solve

The present invention finishes in order to address the above problem, and its purpose is, provides that can to form specific insulation low and have a conductive paste to the conducting film of the durability of the excellence of cold cycling.In addition, the present invention also aims to, the substrate of the band conducting film with the conducting film that uses above-mentioned conductive paste is provided.

For the scheme of dealing with problems

Conductive paste of the present invention is characterised in that, contains to have the phenol hydroxyl in the molecule shown in copper particle (A), thermosetting resin (B) and the following general formula (1) and at least one contains the aromatic compound (C) of ester bond group.

[Chemical formula 1]

Symbol in the formula (1) is as follows.

R ₁: aliphatic alkyl or hydrogen atom.

R ₂: contain the ester bond group shown in aliphatic alkyl, hydrogen atom or the following formula (2).

R ₃: contain the ester bond group shown in the following formula (2).

R ₄: contain the ester bond group shown in aliphatic alkyl, hydrogen atom or the following formula (2).

R ₅: aliphatic alkyl or hydrogen atom.

[Chemical formula 2]

(in the formula (2), R ₆Be aliphatic alkyl, n is 1 ~ 4 integer.)

In conductive paste of the present invention, preferred aforementioned aromatic compound (C) only has the described ester bond group that contains at 4 of phenyl ring.In addition, with respect to the aforementioned copper particles of 100 mass parts (A), the content of aforementioned aromatic compound (C) is preferably 0.005 ~ 0.5 mass parts.

In addition, preferred conductive paste of the present invention also contains the carboxylate (D) of the macromolecular compound that has primary amino radical in the molecule.In addition, aforementioned macromolecular compound with primary amino radical is preferably polymine or polyallylamine.In addition, the carboxylate of aforementioned (D) composition is preferably formates.

In addition, preferred conductive paste of the present invention also comprises by being the stability constant logK of the copper ion of 0.1mol/L with ionic strength down at 25 ℃ _CuIt is the chelating agent (E) that 5 ~ 15 compound forms.Aforementioned chelating agent (E) is preferably and disposes the functional group (a) that comprises nitrogen-atoms and the aromatic compound of the functional group (b) that comprises the atom with lone electron pair except nitrogen-atoms at the ortho position of aromatic rings.In addition, the atom with lone electron pair except nitrogen-atoms of the nitrogen-atoms of the aforementioned functional groups (a) of preferred aforementioned chelating agent (E) and aforementioned functional groups (b) clips two or three atoms and is connected.Aforementioned chelating agent (E) is preferably at least a compound that is selected from the group of being made up of bigcatkin willow hydroximic acid, salicylaldoxime and o-aminophenol.

In addition, it is 1 ~ 4 organic acid, ester or acid amides (F) that preferred conductive paste of the present invention also comprises pKa, and aforementioned organic acid ester or acid amides (F) are preferably and are selected from least a in the group of being made up of formamide, gaultherolin, dimethyl oxalate, dimethyl malenate and dimethyl maleate.In addition, with respect to the aforementioned hot thermosetting resin (B) of 100 mass parts, the content of aforementioned organic acid ester or acid amides (F) is preferably 0.5 ~ 15 mass parts.

And then in conductive paste of the present invention, aforementioned hot thermosetting resin (B) is preferably and is selected from least a in phenolic resins, melamine resin and the Lauxite.In addition, with respect to the aforementioned copper particle (A) of 100 mass parts, the content of aforementioned hot curable resin (B) is preferably 5 ~ 50 mass parts.

The base material of preferred band conducting film of the present invention has the conducting film that aforementioned conductive paste is solidified to form at base material.In addition, the specific insulation of aforementioned conducting film is preferably 1.0 * 10 ^-4Below the Ω cm.

The manufacture method of the base material of band conducting film of the present invention is characterised in that, be coated on aforementioned conductive paste of the present invention on the base material after, this conductive paste of heating makes its curing under the temperature of 150 ℃ of less thaies, forms conducting film.

The effect of invention

According to conductive paste of the present invention, can access the conducting film that specific insulation is low and the thermal shock that is caused by cold cycling etc. is had excellent durability.In addition, by using this conductive paste, can access as the reliability height of circuit board etc. and can suppress because forming the base material of the band conducting film that specific insulation that the oxidation overlay film causes rises.

Description of drawings

Fig. 1 is the key diagram that the summary formation of the device of handling for the wet type reduction of implementing the copper particle is shown.

Fig. 2 is the generalized section of an example that the base material of band conducting film of the present invention is shown.

Description of reference numerals

1 ... reactive tank, 2 ... upper electrode, 3 ... lower electrode, 4 ... object being treated, 5 ... AC power, 6 ... solid dielectric, 7 ... gas introduction port, 8 ... gas discharge outlet, 9 ... insulant, 10 ... the base material, 11 of band conducting film ... base material, 12 ... conducting film.

Embodiment

Below, embodiments of the present invention are elaborated.

[conductive paste]

The conductive paste of embodiments of the present invention contains and has the phenol hydroxyl in the molecule shown in copper particle (A), thermosetting resin (B), the specific structural formula and at least one contains the aromatic compound (C) of ester bond group.The conductive paste of embodiments of the present invention can also contain the carboxylate (D) of the macromolecular compound that has primary amino radical in the molecule.In addition, can contain by descending with ionic strength at 25 ℃ is the stability constant logK of the copper ion of 0.1mol/L _CuIt is the chelating agent (E) that 5 ~ 15 compound forms.And then, can also contain pKa and be 1 ~ 4 organic acid, ester or acid amides (F).

Conductive paste according to the embodiment of the present invention, contain the aromatic compound (C) of ester bond group owing in copper particle (A) and thermosetting resin (B) compounding molecule, have phenol hydroxyl and at least one, therefore can form the conductive paste of formation of oxidation, the inhibition cupric oxide of the copper particle (A) in the time of suppressing curing.

In addition, the conducting film that is formed by this conductive paste also can prevent with the cupric oxide being the forming of oxidation overlay film of principal component, thereby, can access the base material that also can suppress the band conducting film that specific insulation rises to the thermal shock that is caused by cold cycling.

Below, each composition that contains in the conductive paste to execution mode describes.

＜copper particle (A)＞

Copper particle (A) is the conductive compositions of conductive paste, and the surface oxygen concentration of obtaining by X-ray photoelectron spectroscopy is below 0.5 than O/Cu.Below will be expressed as " surface oxygen concentration is than O/Cu " simply than O/Cu by the surface oxygen concentration that X-ray photoelectron spectroscopy is obtained.

Surface oxygen concentration is to use recently representing by X-ray photoelectron spectroscopic analysis surface oxygen concentration (atom %) that measure, the copper particle and surperficial copper concentration (atom %) than O/Cu.In this specification, " surperficial copper concentration (atom %) " and " surface oxygen concentration (atom %) " is respectively the measured value that obtains carrying out X-ray photoelectron spectroscopic analysis from copper particle surface to the zone, particle top layer of the scope of about 3nm degree of depth to the center.Extremely the scope of about 3nm degree of depth is to grasp the scope of the surface state of copper particle fully by the concentration determination of each composition is carried out in the particle zone of this scope to the center from the copper particle surface.

The surface oxygen concentration of copper particle (A) surpasses at 0.5 o'clock than O/Cu, and the amount of the cupric oxide on copper particle (A) surface is too much, and when forming conducting film, intergranular contact resistance is big, the worry that exists specific insulation to uprise.Be copper particle (A) 0.5 below by using surface oxygen concentration than O/Cu, can reduce the intergranular contact resistance of copper, the conductivity in the time of can improving the formation conducting film.The surface oxygen concentration of copper particle (A) is preferably below 0.3 than O/Cu.

In addition, for copper particle (A), the whole contained oxygen concentration of particle is preferably below the 700ppm.Contained oxygen concentration for example can use oxymeter to measure in the copper particle.

As copper particle (A), as long as surface oxygen concentration is to use various copper particles below 0.5 than O/Cu.Copper particle (A) can be metallic copper particle, also can be hydrogenation copper particulate or metallic copper particulate that hydrogenation copper particulate heating is formed (below be also referred to as the copper particulate).In addition, as copper particle (A), also can be the composite particles of the form that is composited of these metallic copper particles and copper particulate.As composite particles, for example can enumerate the particle that the copper particulate adheres to or be combined in the form that forms on the surface of metallic copper particle.In the back composite particles is described in detail.

The average grain diameter of copper particle (A) is preferably 0.01 ~ 20 μ m.The average grain diameter of copper particle (A) can be adjusted in the scope of 0.01 ~ 20 μ m aptly according to the shape of copper particle (A).The average grain diameter of copper particle (A) is 0.01 μ m when above, and the flow behavior that comprises the conductive paste of this copper particle becomes good.In addition, the average grain diameter of copper particle (A) is 20 μ m when following, becomes and utilizes the conductive paste that comprises this copper particle to make fine wiring easily.

Copper particle (A) is when comprising metallic copper particle, and its average grain diameter (average primary particle diameter) is preferably 0.3 ~ 20 μ m.In addition, when copper particle (A) was only formed by the copper particulate, the average grain diameter of its agglomerated particle was preferably 0.01 ~ 1 μ m, more preferably 0.02 ~ 0.4 μ m.

Copper particle (A) comprises under the situation of metallic copper particle, and its average grain diameter (average primary particle diameter) is 0.3 μ m when above, and the flow behavior that comprises the conductive paste of this copper particle becomes good.In addition, under the situation that copper particle (A) is only formed by the copper particulate, the average grain diameter of its agglomerated particle is 0.01 μ m when above, and the flow behavior that comprises the conductive paste of this copper particle becomes good.

In addition, copper particle (A) comprises under the situation of metallic copper particle, and its average grain diameter (average primary particle diameter) is 20 μ m when following, utilizes the conductive paste that comprises this copper particle to make fine wiring easily.In addition, under the situation that copper particle (A) is only formed by the copper particulate, the average grain diameter of its agglomerated particle is 1 μ m when following, utilizes the conductive paste that comprises this copper particle to make fine wiring easily.

Be copper particle (A) below 0.5 as surface oxygen concentration than O/Cu, for example can use following copper particle (A1) ~ (A5) aptly.

(A1) metallic copper particle, its average primary particle diameter are 0.3 ~ 20 μ m.

(A2) has the copper composite particles of metallic copper particle and hydrogenation copper particulate, the average primary particle diameter of described metallic copper particle is the metallic copper particle of 0.3 ~ 20 μ m, described hydrogenation copper particulate is for being attached to the lip-deep hydrogenation copper of above-mentioned metallic copper particle particulate, and the average grain diameter of its agglomerated particle is 20 ~ 400nm.

(A3) hydrogenation copper particulate, the average grain diameter of its agglomerated particle are 10nm ~ 1 μ m.

(A4) has the copper metal complex particle of metallic copper particle and metallic copper particulate, described metallic copper particle is that average primary particle diameter is the metallic copper particle of 0.3 ~ 20 μ m, described metallic copper particulate will be for being attached to the metallic copper particulate that the heating of the lip-deep hydrogenation copper of above-mentioned metallic copper particle particulate forms, and the average grain diameter of its agglomerated particle is 20 ~ 400nm.

(A5) metallic copper particulate, the average grain diameter of its agglomerated particle are 10nm ~ 1 μ m.

Wherein, copper metal complex particle (A4) is that the hydrogenation copper particulate of copper composite particles (A2) changes the particle that the metallic copper particulate forms into by heat treated.In addition, metallic copper particulate (A5) is that hydrogenation copper particulate (A3) changes the particle that forms by heat treated.

In this manual, average grain diameter is following obtaining.That is, the average primary particle diameter of metallic copper particle is following calculating: measure the Feret footpath of 100 particles from scanning electron microscope (below be designated as " SEM ") image, selecting at random, and these particle diameters are average and calculate.

In addition, the average grain diameter of the agglomerated particle that is formed by the copper particulate is following calculating: measure the Feret footpath of 100 particles from transmission electron microscope (below be designated as " TEM ") image, selecting at random, and these particle diameters are average and calculate.

In addition, for example as copper composite particles (A2), comprise as the copper particle of metallic copper particle and be attached under the situation of composite particles of the hydrogenation copper particulate on this copper particle surface, observe this composite particles integral body by SEM, mensuration comprises the copper particulate in the Feret footpath of all interior particles, and the particle diameter that obtains is on average calculated.

As this copper particle (A), for example can list " the copper metal complex particle " that " the surface modification copper particle " that form or at least a portion on the metallic copper particle surface are attached with the metallic copper particulate handled in copper particle surface reduction.

" surface modification copper particle " among the present invention reduces the copper particle surface to handle and obtains in the pH value is decentralized medium below 3." surface modification copper particle " for example can be made by following wet type reducing process, and described wet type reducing process has (1) the copper particle is dispersed in the decentralized medium, forms the operation of " copper dispersion liquid "; (2) the pH value of copper dispersion liquid is adjusted to operation below the setting; (3) in the copper dispersion liquid, add the operation of so following (1) ~ (3) of the operation of reducing agent.

The surface modification copper particle that operation by above-mentioned (1) ~ (3) obtains mainly is made of metallic copper particle.The average primary particle diameter of surface modification copper particle is preferably 0.3 ~ 20 μ m (metallic copper particle (A1)).For surface modification copper particle, its average primary particle diameter is 0.3 μ m when above, and the flow behavior that comprises the conductive paste of this copper particle becomes good.In addition, the average primary particle diameter of surface modification copper particle is 20 μ m when following, utilizes the conductive paste that comprises this copper particle to make fine wiring easily.

Below, operation (1) ~ (3) of making surface modification copper particle are described.

(1) making of copper dispersion liquid

The copper particle that is dispersed in the copper dispersion liquid can use the copper particle that is typically used as conductive paste.The grain shape that is dispersed in the copper particle in the copper dispersion liquid can be spherical, also can be sheet.

The average grain diameter that is dispersed in the copper particle in the copper dispersion liquid is preferably 0.3 ~ 20 μ m, more preferably 1 ~ 10 μ m.During the average grain diameter less than 0.3 μ m of copper particle, the worry that exists the flowability that makes conductive paste to reduce.On the other hand, when the average grain diameter of copper particle surpasses 20 μ m, be difficult to utilize the conductive paste that obtains to make fine wiring.Be made as 0.3 ~ 20 μ m by the average grain diameter with the copper particle, can form good fluidity and be suitable for the conductive paste of the making of fine wiring.

Need to prove that the average grain diameter of copper particle is to measure the Feret footpath of 100 metallic copper particles selecting at random from the SEM image, calculates its mean value and obtains.

The copper dispersion liquid can by make above-mentioned copper particle form Powdered after, Powdered thing dropped in the decentralized medium and obtain.The concentration of the copper particle of copper dispersion liquid is preferably 0.1 ~ 50 quality %.During the concentration less than 0.1 quality % of copper particle, decentralized medium quantitative change contained in the copper dispersion liquid gets too much, and existence can't maintain production efficiency the worry of sufficient level.On the other hand, when the concentration of copper particle surpassed 50 quality %, the influence of particle reunion each other became excessive, had the worry of the productive rate minimizing of surface modification copper particle.Be made as the scope of 0.1 ~ 50 quality % by the concentration with the copper particle of copper dispersion liquid, can obtain surface modification copper particle with high yield.

As the decentralized medium of copper particle dispersion, as long as can make the copper particle disperse just to be not particularly limited, but can preferably use the decentralized medium with high polarity.As the decentralized medium of high polarity, for example can make alcohols such as water, methyl alcohol, ethanol, 2-propyl alcohol; Glycols such as ethylene glycol; And the blending agent that they are mixed etc.

As the decentralized medium of high polarity, especially preferably make water.

For the copper particle that is dispersed in the decentralized medium, in order to prevent the oxidation of particle surface, can carry out surface treatment to particle surface with surface conditioning agent.As surface conditioning agent, can use long-chain carboxylic acids such as stearic acid, palmitic acid, myristic acid.

When using the long-chain carboxylic acid as surface conditioning agent, preferably after removing long-chain carboxylic acid's (surface conditioning agent), the copper particle surface is dispersed in the decentralized medium again.By remove long-chain carboxylic acid's (surface conditioning agent) from the copper particle surface after, be dispersed in again the decentralized medium, reduction reaction described later is carried out smoothly.

Need to prove, when using the long-chain carboxylic acid as surface conditioning agent, also can directly copper pellet supply to reduction be handled.Removing of long-chain carboxylic acid can be undertaken by for example using methods such as acid cleaning.

In addition, in order to improve the dispersiveness of copper particle in decentralized medium, preferably the copper particle is carried out preliminary treatment.By carrying out preliminary treatment, the copper particle surface is by hydrophiling.Therefore, can improve the dispersiveness of copper particle in the contour polarity decentralized medium of water.

As pretreating agent, for example can use aliphat monocarboxylic acid classes such as the aliphat monocarboxylic acid of carbon number below 6, aliphatic hydroxyl monocarboxylic acid, aliphatic amino acid aptly; And aliphat polybasic carboxylic acid class.As aliphat polybasic carboxylic acid class, for example can list aliphat polybasic carboxylic acid, the aliphatic hydroxyl polybasic carboxylic acid of carbon number below 10.The more preferably aliphat polybasic carboxylic acid class of carbon number below 8.As pretreating agent, particularly, can use glycine, alanine, citric acid, malic acid, maleic acid, malonic acid etc. aptly.

Preferably add dispersant in the copper dispersion liquid that obtains as above operating.As dispersant, can use the water miscible all cpds that the copper particle is had adsorptivity.As dispersant, particularly, for example can use chelates such as water-soluble high-molecular compounds such as polyvinyl alcohol, polyacrylic acid, polyvinylpyrrolidone, hydroxypropyl cellulose, propyl cellulose, ethyl cellulose, EDTA, imino-diacetic acetic acid etc.

The relative copper particle of amount that load is present in through the surface conditioning agent on the copper particle surface after above-mentioned each processing, pretreating agent, dispersant is preferably 0.1 ~ 10 quality %.

Utilize the processing of the copper particle of pretreating agent, dispersant followingly to carry out: to add the copper particle in the solution that obtains pretreating agent etc. being added in the water equal solvent and stir, then, in this solution, to carry out in the mode of copper particle surface load pretreating agent etc.

In order to improve processing speed, when carrying out preliminary treatment, carry out on preferred limit heating copper dispersion liquid limit.As heating-up temperature, preferably carrying out more than 50 ℃ and under the temperature below the boiling point of decentralized medium such as water.In addition, when in decentralized medium, adding surface conditioning agent, dispersant such as carboxylic acid, preferably heating-up temperature is made as below the boiling point of these compounds.

The time of heat treated is preferably more than 5 minutes and below 3 hours.Heating time, less than was in the time of 5 minutes, can't fully the be improved worry of effect of processing speed of existence.On the other hand, when surpassing 3 hours heat treated, the worry that exists cost to become too high is not preferred from the aspect of economy.

In addition, when carrying out preliminary treatment etc., in order to prevent the oxidation of copper particle surface, preferably after in the non-active gas replacement Treatment containers such as nitrogen, argon gas, carry out again.After the preliminary treatment, desolventizing, cleaning such as water as required, thus obtain being dispersed in copper particle in the dispersion liquid.

(2) adjustment of the pH value of copper dispersion liquid

Adjust the pH value of the copper dispersion liquid that obtains in above-mentioned (1).The adjustment of pH value can be undertaken by add the pH conditioning agent in the copper dispersion liquid.

PH conditioning agent as the copper dispersion liquid can use acid.As the pH conditioning agent of copper dispersion liquid, for example can use carboxylic acids such as formic acid, citric acid, maleic acid, malonic acid, acetic acid, propionic acid aptly; Inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid.As carboxylic acid, can use with above-mentioned as the same compound of the carboxylic acid of pretreating agent.

Wherein, as the pH conditioning agent, preferably use carboxylic acid.By using carboxylic acid as the pH conditioning agent, carboxylic acid is adsorbed on the copper particle surface, remains on the surface of the surface modification copper particle after reduction is handled, and protects particle surface, can suppress the oxidation reaction of copper.

Especially, formic acid is owing to contain aldehyde radical with reproducibility and (CHO), remain on the copper particle surface after the surface modification, can suppress the particle surface oxidation.By using this compounding that the conductive paste of copper particle is arranged, can form the conducting film that is difficult for generation oxidation overlay film, can suppresses the specific insulation rising.Need to prove, as the pH conditioning agent, not necessarily be defined in sour composition.When for example the pH value of dispersion liquid is low, also can use alkali as the pH conditioning agent.

Preferably the pH value with the copper dispersion liquid is made as below 3.Be made as below 3 by the pH value with the copper dispersion liquid, can in follow-up reduction treatment process, successfully carry out particle surface oxide-film remove the surface oxygen concentration of the surface modification copper particle that can reduce to obtain.The pH value of dispersion liquid surpasses at 3 o'clock, and existence can't fully be removed and be formed at the effect of the oxide-film on the copper particle surface, can't fully reduce the worry of the oxygen concentration of copper particle surface.On the other hand, preferably the pH value of dispersion liquid is made as more than 0.5.During the pH value less than 0.5 of dispersion liquid, there is the surface modification of copper particle to become to be difficult to the worry of carrying out smoothly in the excessive stripping of copper ion.More preferably be made as the pH value of dispersion liquid more than 0.5 and below 2.Need to prove that the pH value of dispersion liquid is 3 when following, also can be directly this dispersion liquid be reduced processing.

(3) reduction of copper dispersion liquid is handled

In adjusting the copper dispersion liquid of pH value, add reducing agent, reduced processing.

As the reducing agent that is added in the copper dispersion liquid, can use at least a in amine borines such as hypophosphites, dimethylamine boranes such as being selected from metal hydride, hydro-reduction agent, hypophosphorous acid, sodium hypophosphite and the formic acid.As metal hydride, can list lithium hydride, hydrofining and calcium hydride.As the hydro-reduction agent, can list lithium aluminium hydride, lithium borohydride and sodium borohydride.Wherein, can use hypophosphorous acid, sodium hypophosphite aptly.

In addition, as mentioned above, formic acid also can be used as the pH conditioning agent.Therefore, when in decentralized medium, adding formic acid, also work as the pH conditioning agent when working as reducing agent.

For the reducing agent that is added in the copper dispersion liquid, preferably with respect to the copper atom amount of particle surface far away excessive mode add.Particularly, with respect to the total mole number of copper particle contained in the dispersion liquid, preferably add with 1 times of reducing agent more than the amount of molar ratio computing, the molal quantity with respect to whole copper atoms of copper particle can use the reducing agent with 1.2 ~ 10 times of amounts of molar ratio computing.

With respect to the total mole number of copper, when adding the reducing agent of the amount more than 10 times, from the cost aspect, become unfavorable, the worry that exists production cost to become too high.In addition, have that quantitative change from the catabolite of reducing agent gets too much, it removes the worry that becomes complicated.

Reduction reaction preferably is made as 5 ~ 60 ℃ with the temperature of decentralized medium carries out, and more preferably is made as 35 ~ 50 ℃ and carries out.Be made as below 60 ℃ by the temperature with dispersion liquid, can reduce the influence of change in concentration when decentralized medium is removed in evaporation from the copper dispersion liquid, dispersion liquid integral body.

The reduction of copper particle can be added reducing agent as mentioned above and carry out in the copper dispersion liquid, perhaps the copper particle is dispersed in the decentralized medium that is added with reducing agent and carries out.

In addition, the pH value of preferably adding the copper dispersion liquid behind the reducing agent keeps state below 3 from the reaction beginning when reaction finishes.Thus, the removing smoothly of oxide-film of copper particle surface carried out.

The oxidation-reduction potential of copper dispersion liquid can wait aptly and adjust according to addition, the kind of reducing agent.The oxidation-reduction potential of copper dispersion liquid is preferably 100 ~ 300mV with respect to the current potential of standard hydrogen electrode (SHE), more preferably 100 ~ 220mV.By with respect to the current potential of standard hydrogen electrode (SHE) oxidation-reduction potential of copper dispersion liquid being made as 100 ~ 300mV, the reduction reaction of copper ion is carried out smoothly.

In addition, oxidation-reduction potential can be to obtain with the form of the potential difference of normal electrode.In this specification, oxidation-reduction potential is represented as the potential difference that normal electrode records by using standard hydrogen electrode.

After the decomposition of reducing agent finishes substantially, with surface modification the copper particle from dispersion liquid, separate.Then, cleaning, drying such as water as required, can access surface oxygen concentration than O/Cu be below 0.5 surface modification copper particle, be copper particle (A) powder.Than O/Cu, in the operation of above-mentioned (1) ~ (3), the adjustment of the adjustment of pH value that can be by for example copper dispersion liquid, the oxidation-reduction potential of copper dispersion liquid is adjusted to the scope of expectation for the surface oxygen concentration of copper particle (A).

By carrying out the surface treatment of above-mentioned operation (1) ~ (3), can will be present in as the cupric oxide (Cu on the copper particle surface of initiation material ₂O, CuO) be reduced into copper atom, can reduce the amount as the cupric oxide of the main cause that hinders conductivity.

In addition, accessory substance such as reducing agent analyte is generally the composition that dissolves in decentralized medium.Therefore, by filtration, centrifugation, can be with copper particle and these component separation.

In addition, for the copper particle surface after the surface treatment of above-mentioned operation (1) ~ (3), by reducing agent, a part of copper atom is reduced, and generates hydrogenation copper.Therefore, the copper particle after the surface treatment can change hydrogenation copper into copper by carry out heat treated under 40 ~ 120 ℃ after separating from dispersion liquid sometimes.

" copper metal complex particle " among the present invention is the metallic copper particulate to be attached at least a portion on metallic copper particle surface form." copper metal complex particle " is attached to hydrogenation copper particulate and forms " copper composite particles " on the metallic copper particle surface and heat, and makes hydrogenation copper particulate change the metallic copper particulate into and obtains.Need to prove that the metallic copper particle surface has or not adhering to of particulate can observe the SEM image to confirm.In addition, the detection that is attached to the lip-deep hydrogenation copper particulate of metallic copper particle can be used X-ray diffractometer (Rigaku company makes, and TTR-III) carries out.

The metallic copper particle of copper composite particles can use the known copper particle that is generally used for conductive paste.The grain shape of metallic copper particle can be spherical, also can be sheet.

The average grain diameter of the metallic copper particle of copper composite particles is preferably 0.3 ~ 20 μ m, more preferably 1 ~ 10 μ m.

During the average grain diameter less than 0.3 μ m of metallic copper particle, can't obtain sufficient flow behavior when forming conductive paste.On the other hand, when the average grain diameter of metallic copper particle surpasses 20 μ m, exist to be difficult to utilize the conductive paste that obtains to make the worry of fine wiring.The average grain diameter of metallic copper particle is 1 ~ 10 μ m more preferably.Need to prove that the average grain diameter of metallic copper particle is to measure the Feret footpath of 100 metallic copper particles selecting at random from the SEM image, and this measured value is on average calculated.

The hydrogenation copper particulate of copper composite particles mainly exists with the reunite form of the second particle form of the primary particle about 1 ~ 20nm.The grain shape of hydrogenation copper particulate can be spherical, also can be sheet.The average grain diameter of the agglomerated particle of hydrogenation copper particulate is preferably 20 ~ 400nm, more preferably 30 ~ 300nm, more preferably 50 ~ 200nm.Be preferably 80 ~ 150nm especially.During the average grain diameter of the agglomerated particle of hydrogenation copper particulate is not enough 20nm, the welding growth of hydrogenation copper particulate taking place easily, when forming conducting film, has the worry that is accompanied by unfavorable conditions such as volume contraction cracks.On the other hand, when the average grain diameter of the agglomerated particle of hydrogenation copper particulate surpassed 400nm, granule surface area was insufficient, is difficult to take place the surface melting phenomenon, was difficult to form fine and close conducting film.The average grain diameter of hydrogenation copper particulate is to measure the Feret footpath of 100 hydrogenation copper particulates selecting at random from the TEM image, and this measured value is on average calculated.

As the copper composite particles, the composite particles (copper composite particles (A2)) that preferably has metallic copper particle and hydrogenation copper particulate, the average primary particle diameter of described metallic copper particle is 0.3 ~ 20 μ m, described hydrogenation copper particulate is for being attached to the lip-deep hydrogenation copper of this metallic copper particle particulate, and the average grain diameter of its agglomerated particle is 20 ~ 400nm.

The amount that is attached to the lip-deep hydrogenation copper of metallic copper particle particulate is preferably 5 ~ 50 quality % of the amount of metallic copper particle, more preferably 10 ~ 35 quality %.

The amount of hydrogenation copper particulate can't form conductive path between metallic copper particle during with respect to the quantity not sufficient 5 quality % of metallic copper particle fully, and existence can't fully obtain reducing the worry of effect of the specific insulation of conducting film.On the other hand, when the amount of hydrogenation copper particulate surpasses 50 quality % with respect to the amount of metallic copper particle, be difficult to guarantee the sufficient flowability as conductive paste.

Need to prove, for the amount of the lip-deep hydrogenation copper particulate that is attached to metallic copper particle, the difference of residual copper ion concentration calculates in the reactant liquor after for example can finishing by the copper ion concentration in the water-soluble copper compound solution before the adding reducing agent, with the generation of hydrogenation copper particulate.

The copper composite particles can be made by for example following wet type reducing process, and described wet type reducing process has (i) forms hydrogenation copper particulate by reaction system (R) operation; (ii) in reaction system (R), drop into metallic copper particle, hydrogenation copper particulate is attached on the metallic copper particle surface and forms the operation of " copper composite particles "; The (iii) operation of such following (i) ~ (iii) of the operation that " copper composite particles " separated from reaction system (R).By heating this copper composite particles, making hydrogenation copper particle conversion is the metallic copper particulate, can access " copper metal complex particle ".

Need to prove that in this manual, " reaction system (R) " refers to generate the system of hydrogenation copper particulate.Reaction system (R) comprises that not only (α) adds the system of the unreacted state of reducing agent in water-soluble copper compound solution, also comprise (β) by the reaction of water-soluble copper compound and reducing agent, the system that is generated as ongoing state of hydrogenation copper particulate; (γ) reaction of formation of hydrogenation copper particulate finishes, the system of the state that the hydrogenation copper particle after the generation disperses.

That is, " reaction system (R) " refers to remain in after hydrogenation copper particulate generates various ions in the solvent, other residue, reducing agent, its analyte etc. and is present in the system in the water equal solvent with water-soluble copper compound, copper ion, various anion.Therefore, the hydrogenation copper particulate after generating is separated from solution, is dispersed in the decentralized medium and the dispersion liquid that obtains does not belong to the reaction system (R) in this specification.

Below, describe to the operation (i) ~ (iii) of manufactured copper composite particles and by the method that this copper composite particles is made the copper metal complex particle.

(i) formation of hydrogenation copper particulate

At least add reducing agent in the water-soluble copper compound solution that reaction system (R) can form water-soluble copper compound being added in the solvent and form.

Water miscible copper compound as forming reaction system (R) is preferably mantoquita.As mantoquita, more preferably use the salt of copper (II) ion and inorganic acid or carboxylic acid.As the carboxylic acid that forms mantoquita, the carbon atom that preferably comprises carboxyl is 1 ~ 4 carboxylic acid at interior carbon number, special preferable formic acid, acetic acid or propionic acid.As water miscible copper compound, especially preferably use copper sulphate, copper nitrate, copper formate, Schweinfurt green, copper chloride, copper bromide, cupric iodide etc.

Need to prove, as the solvent of above-mentioned water-soluble copper compound solution, just can be not particularly limited to use as long as can dissolve water-soluble copper compound.As the solvent of water-soluble copper compound solution, can especially preferably make water.

The concentration of contained water-soluble copper compound is preferably 0.1 ~ 30 quality % with respect to solution 100 quality % in the water-soluble copper compound solution.During the concentration less than 0.1 quality % of water-soluble copper compound, the amount of moisture in the solution becomes too much, and the formation efficiency of hydrogenation copper particulate reduces.On the other hand, when the concentration of water-soluble copper compound surpasses 30 quality %, the worry that exists the productive rate of hydrogenation copper particulate to reduce on the contrary.

Water-soluble copper compound solution for adding reducing agent preferably is adjusted to the pH value below the setting.As the pH conditioning agent of water-soluble copper compound solution, can use the material same with the sour composition of in the explanation of the manufacturing process of surface modification copper particle, enumerating as the pH conditioning agent of copper dispersion liquid.Particularly, for example can use formic acid, citric acid, maleic acid, malonic acid, acetic acid, propionic acid, sulfuric acid, nitric acid, hydrochloric acid etc.

Wherein, as the pH conditioning agent of water-soluble copper compound solution, can use formic acid especially aptly.Formic acid (CHO), remains in particle surface, can suppress the oxidation of copper particulate owing to containing the aldehyde radical with reproducibility.

Preferably the pH value with water-soluble copper compound solution is set at below 3.Be set at below 3 by the pH value with water-soluble copper compound solution, can improve the formation efficiency of hydrogenation copper particulate.Infer that this is to reduce processing under the state that exists in solution because can mix with hydrogen ion at copper ion.The pH value of water-soluble copper compound solution surpasses at 3 o'clock, generates the metallic copper particulate sometimes easily, and the production rate of hydrogenation copper particulate reduces.From the viewpoint of the production rate that improves hydrogenation copper particulate, more preferably the pH value with water-soluble copper compound solution is made as 0.5 ~ 2.

As reducing agent, can use at least a in amine borines such as hypophosphites, dimethyamine borane such as being selected from metal hydride, hydro-reduction agent, hypophosphorous acid, sodium hypophosphite and the formic acid.As metal hydride, can list lithium hydride, hydrofining and calcium hydride.As the hydro-reduction agent, can list lithium aluminium hydride, lithium borohydride and sodium borohydride.Wherein, can use hypophosphorous acid, sodium hypophosphite aptly.Need to prove that as mentioned above, formic acid also can be used as the pH conditioning agent, when therefore in decentralized medium, adding formic acid, also work as the pH conditioning agent when working as reducing agent.

Preferably with respect to the copper ion in the solution to be the reducing agent that 1.2 ~ 10 times equivalents adds water-soluble copper compound solution.The amount of the reducing agent that adds in the water-soluble copper compound solution is difficult to obtain sufficient reduction during with respect to the equivalents of 1.2 times of the quantity not sufficients of copper ion.On the other hand, when the addition of reducing agent surpasses 10 times equivalents with respect to the amount of copper ion, increase the content of the impurity such as sodium, boron, phosphorus of hydrogenation copper particulate sometimes.

The reductant solution that reaction system (R) for example can mix above-mentioned reducing agent and water equal solvent, mix to form with water-soluble copper compound solution.In addition, reaction system (R) also can be added on the reducing agent of solid state in the water-soluble copper compound solution and form.For the reaction system (R) of formation like this, under acid condition, copper ion is reduced the agent reduction, generates hydrogenation copper particulate, germination.

The (ii) formation of copper composite particles

Drop into metallic copper particle in the reaction system (R) that in above-mentioned (i), forms, hydrogenation copper particulate is attached on this metallic copper particle surface, form " copper composite particles ".

At first, in reaction system (R), drop into metallic copper particle.Need to prove that the shape of metallic copper particle, particle diameter are as mentioned above.

Preferably metallic copper particle is added in the reaction system (R) or water-soluble copper compound solution in the stage that has copper ion.

By in having the reaction system of copper ion (R), adding metallic copper particle, can under the environment of metallic copper particle and the coexistence of hydrogenation copper particulate, carry out the reduction reaction of copper ion.Therefore, can between metallic copper particle and hydrogenation copper particulate, form firm bonding state.Need to prove, have or not the concentration determination of the copper ion that copper ion can be by using cupric ion electrode, visible absorption spectrum to confirm in the reaction system (R).In addition, have or not copper ion to exist also the mensuration of oxidation-reduction potential that can be by the aqueous solution to confirm.

That is, preferably metallic copper particle is added in the reaction system (R) in the generation way of hydrogenation copper particulate.In addition, preferably add metallic copper particle in the water-soluble copper compound solution before adding reducing agent, add reducing agent then, form reaction system (R).Preferably, can add metallic copper particle in the reaction system (R) in the generation way of hydrogenation copper particulate.

In addition, the reaction system (R) of interpolation metallic copper particle is not limited to the reaction system of above-mentioned state.For example, also metallic copper particle can be added on because of the copper ion amount in the carrying out reaction system (R) of reduction reaction, reduction dosage reduce and the reaction system (R) of the state that the generation of hydrogenation copper particulate, the growth of hydrogenation copper particulate after generating have stopped in.That is, metallic copper particle can drop in the reaction system (R) that generates before the hydrogenation copper particulate, also can drop into hydrogenation copper particulate and generate in the reaction system (R) in the way, can also drop in addition in the reaction system (R) that generates behind the hydrogenation copper particulate.

By drop into metallic copper particle in reaction system (R), hydrogenation copper particulate is attached on this metallic copper particle surface, can form in reaction system (R) " copper composite particles ".

The amount of the copper ion of the water-soluble copper compound solution preceding with respect to the reducing agent interpolation, the amount that adds copper ion contained in the reaction system (R) of metallic copper particle is preferably 1 ~ 100 quality %, more preferably 5 ~ 100 quality %.Need to prove, set the whole ionizations of copper in the water-soluble copper compound solution.

The temperature of reaction system (R) is preferably below 60 ℃.Be made as below 60 ℃ the decomposition of the hydrogenation copper particulate in can inhibitory reaction system (R) by the temperature with reaction system (R).

For metallic copper particle, be the scope of 100 ~ 300mVSHE, the state of the scope of the 100 ~ 220mVSHE interpolation of getting off more preferably in the oxidation-reduction potential of reaction system (R) preferably.

Need to prove that " SHE " refers to standard hydrogen electrode.In addition, " mVSHE " expression is that benchmark is measured the oxidation-reduction potential that obtains with the standard hydrogen electrode.In this manual, the measured value of oxidation-reduction potential is that benchmark is measured and obtained with the standard hydrogen electrode.

The (iii) separation of copper composite particles

The copper composite particles that forms in the reaction system (R) is separated from this reaction system (R).

Method as the copper composite particles is separated from reaction system (R) is not particularly limited.As the method that the copper composite particles is separated from reaction system (R), for example, can be by the copper composite particles of methods such as centrifugation, filtration separated powder shape from reaction system (R).

From reaction system behind the separating copper composite particles, utilize cleaning fluids such as water to carry out cleaning such as removing with being attached to dissolubility impurity on the particle surface.By so the copper composite particles after separating being carried out refinement treatment, can access the pulverous copper composite particles that is attached with hydrogenation copper particulate on the metallic copper particle surface.In addition, also can before the separation of carrying out the copper composite particles, replace the solvent of reaction system (R), the impurity such as analyte of reducing agent are removed with solvent.

The copper composite particles that obtains separating from reaction system (R) carries out heat treated, and making hydrogenation copper particle conversion is the metallic copper particulate.Thus, obtaining surface oxygen concentration is copper metal complex particle below 0.5 than O/Cu.

The metallic copper particulate of copper metal complex particle by existing between metallic copper particle can form conductive path, the specific insulation in the time of can reducing to form conducting film reliably.In addition, be the metallic copper particulate by making hydrogenation copper particle conversion as mentioned above, can be difficult for taking place the situation that the metallic copper particulate is peeled off from metallic copper particle.Therefore, can form the conductive paste that can suppress to be free in owing to the metallic copper particulate conductive paste viscosity rising that causes in the conductive paste.

The heat treated of copper composite particles is preferably carried out under 60 ~ 120 ℃ temperature.When heating-up temperature surpasses 120 ℃, the welding each other of metallic copper particulate takes place easily, the worry that exists the specific insulation when forming conducting film to uprise.On the other hand, during 60 ℃ of heating-up temperature less thaies, required time of heat treated is elongated, from the aspect of manufacturing cost, is not preferred.

The heat treated of copper composite particles is more preferably carried out under 60 ~ 100 ℃, further preferably carries out under 60 ~ 90 ℃.In addition, the remnant of moisture content of the copper metal complex particle that obtains after the heat treated is preferably below the 3 quality %, more preferably below the 1.5 quality %.

The heat treated of copper composite particles preferably counting-101 with relative pressure ~-carry out under the decompression of 50kPa.When carrying out heat treated under the pressure greater than-50kPa, the dry required time is elongated, from the aspect of manufacturing cost, is not preferred.On the other hand, when the pressure during with heat treated is made as deficiency-101kPa, need to use large-scale device in the removing of unnecessary solvent such as for example water, drying, manufacturing cost uprises on the contrary.

Surface oxygen concentration for " copper metal complex particle " compares O/Cu, can be by in the operation of above-mentioned (i) ~ (iii), adjust pH value, the oxidation-reduction potential of reaction system (R) or the temperature of reaction system (R) etc. of water-soluble copper compound solution, partial pressure of oxygen when perhaps adjusting the heat treated of copper composite particles etc., thus be adjusted to the scope of expectation.

The average primary particle diameter of the metallic copper particle of the copper metal complex particle that obtains through above-mentioned each operation is preferably 0.3 ~ 20 μ m.In addition, the average grain diameter that is attached to the agglomerated particle of the lip-deep metallic copper particulate of metallic copper particle is preferably 20 ~ 400nm (copper metal complex particle (A4)).

During the average grain diameter less than 0.3 μ m of the metallic copper particle of " copper metal complex particle ", when forming conductive paste, can't obtain sufficient flow behavior.On the other hand, when the average grain diameter of metallic copper particle surpasses 20 μ m, be difficult to utilize the conductive paste that obtains to make fine wiring.The average grain diameter of the metallic copper particle in " copper metal complex particle " is 1 ~ 10 μ m more preferably.

The copper particulate of " copper metal complex particle " and the hydrogenation copper particulate in the copper composite particles are equally, mainly exist with the reunite form of the second particle form of the primary particle about 1 ~ 20nm.The grain shape of copper particulate can be spherical, also can be sheet.During the average grain diameter of the agglomerated particle of copper particulate is not enough 20nm, the welding growth of copper particulate taking place easily, when forming conducting film, has the worry of following unfavorable conditions such as volume contraction cracks.On the other hand, when the average grain diameter of the agglomerated particle of copper particulate surpassed 400nm, granule surface area was insufficient, is difficult to take place the surface melting phenomenon, was difficult to form fine and close conducting film.The average grain diameter of the agglomerated particle of copper particulate is 30 ~ 300nm more preferably, further preferred 50 ~ 200nm.Be preferably 80 ~ 150nm especially.

Need to prove that the average grain diameter of metallic copper particle is to measure the Feret footpath of 100 metallic copper particles selecting at random from the SEM image, and this measured value is on average calculated.In addition, the average grain diameter of copper particulate is to measure the Feret footpath of 100 hydrogenation copper particulates selecting at random from the TEM image, and this measured value is on average calculated.

As other copper particle (A), also can preferably use the average grain diameter of agglomerated particle to be the hydrogenation copper particulate (A3) of 10nm ~ 1 μ m.Hydrogenation copper particulate (A3) for example can use the solution of the water-soluble copper compound that uses in the manufacturing processes such as " copper composite particles " to form.Particularly, for example, can be by in the solution of this water-soluble copper compound, being below 3 and oxidation-reduction potential is 100 ~ 300mVSHE, is preferably under the condition of 100 ~ 220mVSHE and adds reducing agent in the pH value, thus obtain.As reducing agent, can use the same reducing agent of reducing agent that uses in the manufacturing process with " copper composite particles ".

Need to prove, reaction temperature, reaction time when the average grain diameter of the agglomerated particle of hydrogenation copper particulate can be passed through the control reduction reaction, perhaps add dispersant adjustment.

As copper particle (A), also can use aptly this hydrogenation copper particulate (A3) is carried out heat treated and the metallic copper particulate (A5) that obtains.That is, as copper particle (A), also can use metallic copper particulate (A5) aptly, the average grain diameter of the agglomerated particle of this metallic copper particulate is 10nm ~ 1 μ m.

In addition, be the method for the copper particle (A) below 0.5 as obtaining surface oxygen concentration than O/Cu, be not limited to the method for utilizing aforesaid wet type reduction.Be the method for the copper particle (A) below 0.5 as obtaining surface oxygen concentration than O/Cu, for example also can clean the lip-deep oxide-film that is formed at copper powders may by using acid such as hydrochloric acid, sulfuric acid, nitric acid, oxide-film is dissolved remove to carry out.

In addition, be the method for the copper particle (A) below 0.5 as being used for obtaining surface oxygen concentration than O/Cu, except said method, can also in this gas, the copper particle be carried out heat treated and wait to carry out by for example in reduction furnace, importing reducibility gas.

Particularly, for example, at first, by importing reducibility gas such as hydrogen, carbon monoxide, natural gas, decomposed ammonia, perhaps make the inner vacuum that is, make to be reducing atmosphere in the reduction furnace.Then, in this reduction furnace, put into the copper particle, under 120 ~ 400 ℃ temperature range, the copper particle is reduced processing, thereby can remove the oxide of particle surface.

In addition, as other method of using reducibility gas, also can be by in the mist of non-active gas and reducibility gas, producing plasma, the method for the copper particle surface being carried out plasma treatment is reduced processing to the copper particle surface.

For example, as shown in Figure 1, supply with the mist of non-active gas and reducibility gas from the electric wire that has gas exhaust port 8 and guarantee to supply with in the chamber electricity and the gas introduction port 7 of the reactive tank 1 of the insulant 9 of the insulation of chamber, turning round is connected AC power 5 on the flat upper electrode 2.Then, between upper electrode 2 and lower electrode 3, produce plasma by glow discharge, and the zone between upper electrode 2 and lower electrode 3, particularly for the solid dielectric 6 configuration object being treateds 4 of mounting on lower electrode 3, be the copper particle, thus, can reduce processing to this copper particle surface.

In addition, as other method of the surface oxygen concentration of adjusting the copper particle, also can followingly carry out: when copper particle and following thermosetting resin (B) etc. are mixed, use triple-roller mill, ball mill (paste) integral body that stirs the mixture.

＜thermosetting resin (B)＞

The thermosetting resin that contains in the conductive paste as embodiments of the present invention (B) can use the known thermosetting resin of the resinoid bond that is typically used as conductive paste.

As thermosetting resin (B), for example, can use phenolic resins, melamine resin, Lauxite etc. aptly.Wherein, the suitable especially phenolic resins that uses.As phenolic resins, can use phenolic varnish type phenolic resins, resol type phenol resin, wherein the suitable especially resol type phenol resin that uses.

In addition, for the glass transition temperature (Tg) of regulating resin, also can in above-mentioned thermosetting resin, contain aptly and be selected from least a in diallyl phthalate resin, unsaturated alkyd resin, epoxy resin, isocyanate resin, bismaleimide-triazine resin, organic siliconresin and the acrylic resin.

For thermosetting resin (B), can the resinous principle after curing do not hinder in the scope of conductivity and add.The content of the thermosetting resin in the conductive paste (B) can according to the volume of copper particle, and the copper particle between the ratio of volume in the space that exists select aptly.Copper particle (A) with respect to 100 mass parts is preferably 5 ~ 50 mass parts, more preferably 5 ~ 20 mass parts.Thermosetting resin (B) contain quantity not sufficient 5 mass parts the time, be difficult to obtain the sufficient flow behavior as conductive paste.On the other hand, when the content of thermosetting resin (B) surpasses 50 mass parts, exist the resinous principle after solidifying to hinder the intergranular contact of copper, the worry that the specific insulation of electric conductor rises.

＜aromatic compound (C)＞

The aromatic compound that contains in the conductive paste of embodiments of the present invention (C) be shown in the following general formula (1), have the phenol hydroxyl in the molecule and at least one contains the compound of ester bond group.

[chemical formula 3]

In the formula (1), R ₁And R ₅Expression aliphatic alkyl or hydrogen atom.As aliphatic alkyl, so long as having the aliphatic alkyl of the monovalencies such as alkyl of unsaturated bond, the such cyclic hydrocarbon group of chain alkyl, the cyclohexyl of short chain, long-chain, vinyl, pi-allyl etc. just can use with being not particularly limited.As aliphatic alkyl, preferred especially carbon number 1 ~ 6 just-, secondary-, uncle-chain alkyl.

R ₂And R ₄Expression contains the ester bond group shown in aliphatic alkyl, hydrogen atom or the aftermentioned formula (2).As aliphatic alkyl, so long as having the aliphatic alkyl of the monovalencies such as alkyl of unsaturated bond, the such cyclic hydrocarbon group of chain alkyl, the cyclohexyl of short chain, long-chain, vinyl, pi-allyl etc. just can use with being not particularly limited.As aliphatic alkyl, preferred especially carbon number 1 ~ 6 just-, secondary-, uncle-chain alkyl.

R ₃Represent to contain the ester bond group shown in the following formula (2).

[chemical formula 4]

In the formula (2), R ₆The expression aliphatic alkyl.As aliphatic alkyl, so long as having the aliphatic alkyl of the monovalencies such as alkyl of unsaturated bond, the such cyclic hydrocarbon group of chain alkyl, the cyclohexyl of short chain, long-chain, vinyl, pi-allyl etc. just can use with being not particularly limited.N is 1 ~ 4 integer, is preferably 2 ~ 3 integer especially.

Reason as using the aromatic compound (C) shown in the aforementioned formula (1) aptly can list following reason.

(i) contain ester bond group (formula (2)) owing to have at least one in the molecule of aromatic compound (C), thereby the phenol OH base of this esteratic site and thermosetting resin (for example, phenolic resins, melamine resin, Lauxite) or methylol OH base generation ester exchange reaction.Its result, aromatic compound (C) can be when conducting film forms and resin-bonded as matrix, thereby can show antioxidant effect for a long time.

What (ii) exist in the molecule of aromatic compound (C) (for example contains ester bond group (formula (2)) and thermosetting resin, phenolic resins, melamine resin, Lauxite) phenol OH base or methylol OH base ester exchange reaction takes place, its result, aromatic compound (C) can be when conducting film forms and resin-bonded as matrix.Therefore, in thermal cycling test, the aromatic compound (C) of the sufficient amount of antioxidant effect can be compounding can shown, sufficient antioxidant effect can be shown.

From the big viewpoint of effect of the oxidation of and copper particle (A) when preventing initial stage and applying cold cycling etc. good with the compatibility of aforementioned hot thermosetting resin (B), as the aromatic compound (C) shown in the aforementioned formula (1), preferred especially R ₁And R ₅For carbon number 1 ~ 6 just-, secondary-, uncle-chain alkyl or hydrogen atom and R ₂And R ₄For hydrogen atom, only have the aforementioned compound that contains the ester bond group 4 of phenyl ring.

The object lesson of the aromatic compound that contains in the conductive paste as execution mode (C) can list following compound, but is not limited to these compounds.

Be 1 the compound that contains the ester bond group as having n in the aforementioned formula (2), can list (4-hydroxyphenyl) methyl acetate, (4-hydroxyphenyl) ethyl acetate, (3,5 ?, two uncle Ding Ji ?, 4 ?hydroxyphenyl) acetic acid stearyl, (3,5 ?, two first base ?, 4 ?hydroxyphenyl) methyl acetate etc.

Be 2 the compound that contains the ester bond group as having n in the aforementioned formula (2), can list 3-(4-hydroxyphenyl) methyl propionate, 3-(4-hydroxyphenyl) ethyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) methyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) ethyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid-6-meptyl ester, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid stearyl, 3-(3 uncle ?Ding Ji ?, 4 ?hydroxyl base ?, 5 ?aminomethyl phenyls) methyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid myristyl ester, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid pentadecyl ester, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) hexyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid dodecyl ester, 3-(3,5-di-t-butyl-4-hydroxyphenyl) the different monooctyl ester of propionic acid, 3,5 ?, two uncle Ding Ji ?, 4 ?hydroxy phenylpropionic acid monooctyl esters, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid cetyl ester, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid-2-Jia Ji ?3 ?oxygen base Shi Jiu Wan ?1 ?the base ester, 3-(3,5-di-t-butyl-4-hydroxyphenyl) butyl propionate, 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid-2-Octyl Nitrite etc.

Be 3 the compound that contains the ester bond group as having n in the aforementioned formula (2), can list 4-(4-hydroxyphenyl) methyl butyrate, 4-(3,5-di-t-butyl-4-hydroxyphenyl) butyric acid stearyl etc.

Be 4 the compound that contains the ester bond group as having n in the aforementioned formula (2), can list 5-(4-hydroxyphenyl) methyl caproate, 5-(4-hydroxyphenyl) caproic acid-2-Octyl Nitrite, 5-[4-hydroxyl-3, the 5-3,5-dimethylphenyl] ethyl hexanoate etc.

Commercially available product as this aromatic compound (C), have: IRGANOX1076 (BASF AG's manufacturing with following chemical formula (3), 3-(3,5-di-t-butyl-4-hydroxyphenyl) IRGANO1135 (BASF AG's manufacturing that propionic acid stearyl), has chemical formula (4), 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid isooctyl acrylate) etc.

[chemical formula 5]

[chemical formula 6]

With respect to the aforementioned copper particle (A) of 100 mass parts, the content of the aforementioned aromatic compound (C) in the conductive paste is preferably the ratio of 0.005 ~ 0.5 mass parts.Aforementioned aromatic compound (C) contain quantity not sufficient 0.005 mass parts the time, prevent that the effect of the oxidation of copper particle (A) from becoming insufficient, when forming conducting film, have the worry of the effect that the specific insulation after the cold cycling that is difficult to fully to be inhibited rises.On the other hand, when the content of aforementioned aromatic compound (C) surpasses 0.5 mass parts, there is to hinder the contact each other of copper particle the worry that conductivity is reduced.

＜contain the carboxylate (D) of amino macromolecular compound＞

The conductive paste of embodiments of the present invention can also further contain the carboxylate (D) of the macromolecular compound that has primary amino radical in the molecule (below, be expressed as contain amino macromolecular compound) on the basis of each composition of aforementioned (A) ~ (C).Contain amino macromolecular compound and be contain at least one in the molecule, preferred a plurality of primary amino radicals, mean molecule quantity (matter average molecular weight Mw) are the amine of 300 ~ 20000 HMW.The mean molecule quantity (Mw) that contains amino macromolecular compound is 600 ~ 10000 scope more preferably.

Preferably, this contains amino macromolecular compound and is containing at least one, containing secondary amino group and/or uncle's amino simultaneously on the basis of preferred a plurality of primary amino radicals, its amine value (according to the regulation of JIS K7237) is preferably 700 ~ 1500mgKOH/g, is preferably 850 ~ 1200mgKOH/g especially.Containing amino macromolecular compound can be the compound with main chain of straight chain shape, also can be the compound with branched structure.The macromolecule amine that wherein especially preferably has branched structure.As containing amino macromolecular compound, particularly, can list polymine, the polyallylamine of the mean molecule quantity (Mw) with aforementioned range.Special preferably polyethylene imines.

In (D) composition, thisly contain amino macromolecular compound and contain with the amino (primary amino radical and secondary amino group and/or uncle's amino) that contained and the form that carboxylic acid reaction forms salt.As forming the acid of salt with the amino that contains amino macromolecular compound, can list hydrochloric acid, sulfuric acid, nitric acid, carboxylic acid, sulfonic acid etc., from the aspect of the intensity appropriateness of the associativity of amino, optimization acid.In the carboxylic acid, the carbon atom that preferably comprises carbonyl is carboxylic acid below 10 at interior carbon number, and preferred especially carbon number is the carboxylic acid below 4.Particularly, special preferable formic acid.

With respect to the aforementioned copper particle (A) of 100 mass parts, (D) the compounding amount that contains the carboxylate of amino macromolecular compound is preferably 0.05 ~ 5 mass parts, is preferably 0.1 ~ 2 mass parts especially.That is, (D) contain amino macromolecular compound carboxylate and be preferably 0.05 ~ 5 quality % with respect to the compounding ratio of copper particle (A), be preferably the scope of 0.1 ~ 2 quality % especially.With respect to the aforementioned copper particle (A) of 100 mass parts, (D) the compounding amount that contains amino macromolecular compound carboxylate is 0.05 mass parts when above, and the adaptation on the conducting film that obtains and ITO film surface becomes good.Be 5 mass parts when following, hinder conductivity and make the situation of specific insulation variation of conducting film few, can form the conducting film with satisfactory electrical conductivity.

＜chelating agent (E)＞

It is the stability constant logK of the copper ion of 0.1mol/L that the conductive paste of embodiments of the present invention can contain by descending with ionic strength at 25 ℃ _CuIt is the chelating agent (E) that 5 ~ 15 compound forms.This chelating agent (E) be by with the copper ion coordination, and can form with the compound that copper ion forms complex compound by the reaction shown in the following reaction equation (5).

[numerical expression 1]

Wherein, the following meaning of the symbolic representation in the formula.

M: copper ion

Z: chelating agent (B)

MZ: complex salt

X: the quantity of the chelating agent (B) of being combined with a copper

Chelating agent (E) is during by the x=1 of above-mentioned reaction equation under 25 ℃, the condition of ionic strength 0.1mol/L and stability constant logK copper ion _CuBe that 5 ~ 15 compound forms.Stability constant logK _CuBe the index in conjunction with intensity of force of expression chelating agent and metal, can be with the balance fixed number K of above-mentioned formula (5) _CuThe form of logarithm value obtain.For K _Cu, particularly, can obtain by following formula (6).

[numerical expression 2]

$K_{\mathrm{Cu}}=\frac{\left[M{Z}_x\right]}{\left[M\right]\·{\left[Z\right]}^x}......\left(6\right)$

(in the above-mentioned formula (6), the concentration of each composition in [] expression parantheses.)

About " the stability constant logKCu " among the present invention, as the concrete numerical value of all cpds, be recorded in for example chemical brief guide (ball is kind), Stability Constants of Metal-Ion Complexes (PERGAMON PRESS), the Journal of Chemical Engineering Data documents such as (ACS Publications).

Think aforementioned stability constant logK by compounding and copper ion _CuBe compound more than 5 as chelating agent (E), at least a portion of the copper ion that produces in the paste and chelating agent (E) formation complex compound.Therefore, can reduce with atmosphere in (O for example such as moisture, oxygen ₂, H ₂O etc.) amount of Fan Ying copper ion can suppress the formation of the cupric oxide in the paste.In addition, chelating agent (E) is owing to be difficult to dissociate with copper ion, even thereby place the state that also can keep complex compound for a long time under the environment of high humility.Therefore, following conductive paste can be accessed, that is, the conductive paste of the conducting film that the rising that be difficult for to generate oxidation overlay film and specific insulation is suppressed can be formed.

The aforementioned stability constant logK of chelating agent (E) _CuDuring less than 5, insufficient to the adhesion of copper ion, thereby can't fully reduce with atmosphere in the amount of copper ion of reactions such as moisture, oxygen, be difficult to suppress the generation of cupric oxide.In addition, the aforementioned stability constant logK of chelating agent (E) _CuSurpass at 15 o'clock, exist chelating agent (E) strong excessively to the adhesion of copper ion, hinder the contact each other of copper particle, the worry that conductivity is reduced.Infer that this is because chelating agent (E) not only works to the copper ion that is present on the copper particle surface, and copper (metallic copper) is worked.Stability constant logK _CuMore preferably 7 ~ 14.

As chelating agent (E), can use following aromatic compound aptly: comprise nitrogen-atoms functional group (a), be disposed at the ortho position of aromatic rings with the functional group (b) that comprises the atom with lone electron pair except nitrogen-atoms, " nitrogen-atoms " of functional group (a) clips two or three atoms with " atom with lone electron pair " of functional group (b) and is connected.

Have the compound of above-mentioned molecular structure by compounding as chelating agent (E), can form stable complex compound with copper ion.

The atom that clips between " atom with lone electron pair " as " nitrogen-atoms " of functional group (a) and functional group (b) can list carbon atom.That is, as chelating agent (E), in aforementioned aromatic compound, can use the nitrogen-atoms of functional group (a) to clip the compound that two or three carbon atoms are connected with the atom with lone electron pair of functional group (b) aptly.

As the group that comprises the functional group (b) with atom lone electron pair, except nitrogen-atoms, for example can list hydroxyl, carboxyl etc. about suitable.

As chelating agent (E), particularly, can use to be selected from least a in bigcatkin willow hydroximic acid, salicylaldoxime, the o-aminophenol.When using salicylaldoxime as chelating agent (E), by the reaction shown in the following reaction equation (I), form the complex compound with copper ion.

[chemical formula 7]

With respect to the aforementioned copper particle (A) of 100 mass parts, the content of the chelating agent in the conductive paste (E) is preferably the ratio of 0.01 ~ 1 mass parts.

Chelating agent (E) contain quantity not sufficient 0.01 mass parts the time, when forming conducting film, can't be inhibited the fully worry of the effect that specific insulation rises of existence.On the other hand, when the content of chelating agent (E) surpasses 1 mass parts, there is to hinder the contact each other of copper particle the worry that conductivity is reduced.

＜organic acid ester or organic acid acid amides (F)＞

It is 1 ~ 4 organic acid, ester or acid amides (F) that the conductive paste of embodiments of the present invention can contain pKa.Organic acid ester or organic acid acid amides as (F) composition are that pKa is 1 ~ 4 organic acid, ester or acid amides, have the function of the curing that promotes aforementioned hot thermosetting resin (B).When compounding has this ester or acid amides (F), by under 120 ~ 140 ℃ low temperature, heating, conductive paste is fully solidified.Therefore, can reduce with atmosphere in the amount of copper ion of contained oxygen reaction, can form the conductive paste that the formation of cupric oxide is suppressed.

Constituting as the ester of (F) composition or the organic acid pKa of acid amides is 1 ~ 4.During organic acid pKa less than 1, exist the keeping quality to conductive paste to cause dysgenic worry.In addition, organic acid pKa surpasses at 4 o'clock, and the generation of the intermediate of the curing of existence promotion aforementioned hot thermosetting resin (C) is slack-off, and the result can't obtain the worry of the curing facilitation effect of resin.Organic acid pKa more preferably 1 ~ 3.

Be 1 ~ 4 organic acid as pKa, can list oxalic acid (1.27), maleic acid (1.92), malonic acid (2.86), salicylic acid (2.97), fumaric acid (3.02), tartaric acid (3.06), citric acid (3.16), formic acid (3.76) etc.

Be 1 ~ 4 organic acid ester or the reason of acid amides as using these pKa aptly, can list following reason.

When (1) using pKa to be 1 ~ 4 organic acid, ester or acid amides, make the effect of intermediate stable existence of thermosetting resin (for example, phenolic resins, melamine resin, Lauxite) big.This be because, above-mentioned ester or acid amides and as the intermediate coordination of the dimethylene ether type of the intermediate of aforementioned hot thermosetting resin.By this coordination, the electron density on the oxygen of a side's of reactive site methylol increases, and the electron density on the carbon of relative methylol reduces, therefore, and the intermediate stable existence of dimethylene ether type.Therefore, the reaction probability of intermediate rises, and solidifies to be promoted, its result can improve conducting film after the curing to the durability of cold cycling.

(2) be the coordination of 1 ~ 4 organic acid, ester or acid amides by pKa, can significantly improve the reactivity of the methylene carbonium ion of above-mentioned intermediate.Therefore, big to the contribution that solidify to promote, can improve conducting film after the curing to the durability of cold cycling.

(3) aforementioned organic acid ester, acid amides are compared with organic acid, and be littler with the reactivity of metal, so the effect of corroding metal is little, the rising of the specific insulation of the conducting film after can suppressing to solidify.The worry that when to use pKa be 1 ~ 4 organic acid monomer, has metal in the corrosion conductive paste, the specific insulation of the conducting film after the curing is risen.

(4) aforementioned organic acid ester, acid amides promote that when paste is preserved the effect of curing of the thermosetting resin in the paste is little, and be therefore, little to the harmful effect that the keeping quality (pot life) of conductive paste causes.

Be 1 ~ 4 organic acid, ester or acid amides as aforesaid pKa, for example can list formamide, gaultherolin, methyl formate, Ethyl formate, dimethyl oxalate, dimethyl maleate, dimethyl malenate etc.Be not limited to them, be selected from least a in them but be preferably.

In these pKa are 1 ~ 4 organic acid, ester or acid amides, can use not organic acid, ester or the acid amides of sulfur-bearing (S) aptly.As its reason, have the reaction of S and copper and generate the worry of sulfide, even thereby existence organic acid ester, acid amides also can cause dysgenic worry to the paste keeping quality.Particularly, can use formamide, gaultherolin, dimethyl oxalate, dimethyl malenate, dimethyl maleate aptly.

With respect to the aforementioned hot thermosetting resin (B) of 100 mass parts, the aforementioned organic acid ester that uses in the conductive paste or the content of acid amides (F) are preferably the ratio of 0.5 ~ 15 mass parts.Aforementioned organic acid ester or acid amides (F) contain quantity not sufficient 0.5 mass parts the time, existence can't obtain promoting the worry of the effect of resin solidification fully.On the other hand, when the content of aforementioned organic acid ester or acid amides (F) surpasses 15 mass parts, there is to hinder the contact each other of copper particle the worry that conductivity is reduced.

＜other composition＞

Conductive paste of the present invention can also comprise solvent as required on the basis of aforementioned each composition in the scope that does not hinder effect of the present invention, various additive (levelling agent, coupling agent, viscosity modifier, antioxidant, driving fit agent etc.) waits other compositions.Especially in order to obtain having the paste body of appropriate flowability, preferably contain the solvent that can make the thermosetting resin dissolving.

As the solvent that contains in the conductive paste, for example can use cyclohexanone, cyclohexanol, terpineol, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monoethylether acetate, ethylene glycol monomethyl ether acetate, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether acetic acid esters, butyl carbitol acetate etc. aptly.

From obtaining to use as printing the viewpoint of the range of viscosities of paste body appropriateness, the amount of the solvent that contains in the conductive paste is preferably 1 ~ 10 quality % with respect to copper particle (A).

The conductive paste of embodiments of the present invention can mix aforementioned each composition and obtain with other compositions such as solvents.The mixing of each composition is preferably carried out in the following order: add aforementioned aromatic compound (C) and mixing in the solution of aforementioned hot thermosetting resin (B) after, add aforementioned copper particle (A) and also mix in mixture.During each composition of compounding aforementioned (D) ~ (F), preferably join in the thermosetting resin (B) with aforementioned aromatic compound (C) and mix.

During the mixing of each composition of aforementioned (A) ~ (F), can carry out in the following heating edge of temperature of the level of the volatilization of the curing that thermosetting resin does not take place, solvent.Mixing, the temperature when stirring preferably are made as 10 ~ 40 ℃.More preferably be made as 20 ~ 30 ℃.When forming conductive paste, be made as the temperature more than 10 ℃, thereby can reduce the viscosity of paste fully, can stir smoothly and fully.In addition, can make the hydrogenation copper that generates at the copper particle surface be converted into copper atom.On the other hand, when the temperature when forming conductive paste surpasses 120 ℃, exist in the curing that thermosetting resin (B) takes place in the paste or the worry that particle welding each other takes place.

In addition, the copper particle is oxidized in order to prevent from mixing, and preferably mixes in the container of replacing with non-active gas.

According to the conductive paste of the present invention of above explanation, in air, also be difficult for oxidizedly even can form, and compare with existing conductive paste because generating the conducting film that specific insulation that cupric oxide causes rises and further is suppressed.

[base material of band conducting film]

The base material 10 of the band conducting film of embodiments of the present invention has the conducting film 12 that above-mentioned conductive paste is solidified to form for example as shown in Figure 2 at base material 11.The base material 10 of this band conducting film can followingly be made: aforementioned conductive paste is coated on the surface of base material 11, forms the conductive paste film, behind the volatile ingredients such as desolventizing, make thermosetting resin cured in the conductive paste, form conducting film 12, thereby make.

As base material 11, (for example can use glass substrate, plastic basis material, the film shape base material, the flat substrates (substrate) that are formed by polyimides, polyester etc.), substrate (for example, glass fiber-reinforced resin substrate) of being formed by fiber reinforced composite material, ceramic substrate etc.When using conductive paste of the present invention, also can be as described later by 150 ℃ of less thaies (for example, 120 ~ 140 ℃) temperature under heating make thermosetting resin (B) be solidified to form conducting film 12, therefore, can use plastic basis materials such as polyester as PETG (PET), PEN (PEN), Merlon aptly.

As the coating process of conductive paste, can list silk screen print method, rolling method, airblade coating method, scraper rubbing method, rod and be coated with known methods such as method, intaglio plate rubbing method, mould are coated with method, coating (slide coat) method of sliding.

Wherein, because can be at the concavo-convex level and smooth wiring shape that is suppressed that forms efficiently on the base material 11 on surface and the side, thereby preferably use silk screen print method.

The curing of thermosetting resin (B) can keep under 120 ~ 200 ℃ temperature by the base material that will be formed with the conductive paste film carrying out.During 120 ℃ of curing temperature less thaies, existing becomes is difficult to worry that thermosetting resin is solidified fully.On the other hand, when curing temperature surpasses 200 ℃, exist and cause the thermosetting resin deterioration, can't obtain the worry as the sufficient durability of cured film.

When especially using base materials such as plastic film as base material, in order to prevent the distortion of base material, preferably under 120 ~ 140 ℃ temperature, keep.Thus, can form the variation conducting film still less of the specific insulation behind the thermal cycling test.

As heating means, can list methods such as warm braw heating, thermal radiation, IR heating.In addition, the formation of conducting film can be carried out in air, perhaps also can carry out in that the few blanket of nitrogen of amount of oxygen is inferior.

For the thickness of the conducting film 12 on the base material 11, from guaranteeing stable conductivity and being easy to keep the viewpoint of wiring shape, be preferably 1 ~ 200 μ m, more preferably 5 ~ 100 μ m.In addition, the specific insulation of conducting film 12 is preferably 1.0 * 10 ^-4Below the Ω cm.The specific insulation of conducting film 12 surpasses 1.0 * 10 ^-4During Ω cm, existence can't obtain the worry of the sufficient conductivity of the electric conductor used as electronic equipment.

Base material 10 for band conducting film of the present invention, owing to use the conductive paste of the invention described above to form conducting film 12, therefore can form the base material of following band conducting film: be difficult for generating the oxidation overlay film that is formed by cupric oxide, compare with the base material of existing band conducting film, specific insulation is lower, even and use the rising also can suppress specific insulation under the environment of the thermal shock as cold cycling.

More than, list an example base material of band conducting film of the present invention be illustrated, but in the scope of main idea of the present invention as required appropriate change constitute.In addition, in the manufacture method of the base material of band conducting film of the present invention, the formation sequential scheduling of each several part also can be in the scope of base material that can make the band conducting film appropriate change.

Embodiment

Below, the present invention will be described by embodiment, but the present invention is not limited to these embodiment.Example 1 ~ 15 is embodiments of the invention, and example 16 ~ 20 is comparative example.

The manufacturing of＜copper particle＞

The copper particle is implemented reduction handle, obtain copper particle (A-1) (surface modification copper particle).At first, in glass beaker processed, drop into the 50 quality % hypophosphorous acid aqueous solution of 3.0g formic acid and 9.0g, this beaker is put into water-bath, remain on 40 ℃.

Then, in this beaker, slowly add 5.0g copper particle (mining company of Mitsui Metal Co., Ltd. makes, trade name: 1400YP, average primary particle diameter 7 μ m), stirred 30 minutes, obtain the copper dispersion liquid.Use centrifugal separator with rotating speed 3000rpm with the copper dispersion liquid centrifugation that obtains 10 minutes, reclaim sediment.This sediment is scattered in the 30g distilled water, by centrifugation diplomatic corps's polymers precipitation again, sediment separate out.The sediment that obtains under the decompression of-35kPa, 80 ℃ of heating 60 minutes down, is made the residual moisture volatilization and slowly removes, obtain particle surface modification copper particle (A-1).

(ULVAC-PHI, Inc. makes, device name: the mensuration of ESCA5500), under the following conditions the copper particle (A-1) that obtains being carried out surface oxygen concentration (atom %) and surperficial copper concentration (atom %) by the X-ray photoelectron spectroscopic analysis device.

Analyze area: 800mm ²Φ

Logical energy (Pass Energy): 93.9eV

Can rank (Energy Step): 0.8eV/step

The surface oxygen concentration that obtains divided by surperficial copper concentration, is calculated surface oxygen concentration than O/Cu, and the surface oxygen concentration of copper particle (A-1) is 0.16 than O/Cu.

In addition, (LECO company makes, the device name: ROH-600) measure the oxygen amount in the copper particle (A-1), be 460ppm to make the oxygen consuming amount meter.

(example 1)

(the flourish chemical company of group makes making 0.74g phenolic resins, trade name: RE SITOP PL6220, resin solid composition 58 quality %) in the resin solution that mixes with the 0.43g ethylene glycol monobutyl ether, (BASF AG makes to add the IRGANOX1076 that is equivalent to aromatic compound of the present invention (C), the trade name of 3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid stearyl) 0.005g.Then, the aforementioned copper particle of compounding 5.0g (A-1) mixes in mortar in the resin solution that obtains thus, obtains conductive paste 1.Wherein, the addition of IRGANOX1076 is the ratio of 0.1 quality % with respect to copper particle (A-1).

(example 2)

Except the addition with IRGANOX1076 is made as the 0.0025g, operate equally with example 1, obtain conductive paste 2.

(example 3)

Except the addition with IRGANOX1076 is made as the 0.025g, operate equally with example 1, obtain conductive paste 3.

(example 4)

Add IRGANOX1135 (BASF AG's manufacturing) 0.005g that is equivalent to aromatic compound of the present invention (C) and replace adding the IRGANOX1076 of 0.005g.In addition operate equally with example 1, obtain conductive paste 4.

(example 5)

Add 0.005g3-(4-hydroxyphenyl) propionic acid methyl ester and replace adding the IRGANOX1076 of 0.005g.In addition operate equally with example 1, obtain conductive paste 5.Wherein, 3-(4-hydroxyphenyl) propionic acid methyl ester is for being equivalent to compound aromatic compound of the present invention (C), shown in the following chemical formula.

[chemical formula 8]

(example 6)

Glass beaker processed is arranged in the water-bath that water temperature is set at 50 ℃, puts into 50g polymine (Japanese catalyst company make trade name: SP012, Mw1200, amine value 1064mmol/g) in beaker, the limit is carried out the vigorous stirring limit and is slowly dripped 43g formic acid.Become lurid aforementioned polymine while smoldering vigorous reaction, become umbrinaceous liquid.After dripping end, former state ground stirred after 30 minutes, reclaimed product in glass container.(Nicolet company makes, the device name: Avatar370) observe product, the result is at 1700cm by FT-IR ^-1Near the peak of the carbonyl that is derived from carboxylic acid that occurs disappears.Thus, can confirm to have generated the salt of polymine and formic acid.

Compounding is as formates (following table the is shown PEI salt) 0.07g of the aforementioned polymine of (D) composition in the resin solution of example 1.In addition, operate equally with example 1, obtain conductive paste 6.Wherein, the compounding amount of PEI salt is the ratio of 1.4 quality % with respect to copper particle (A-1).

(example 7)

Compounding is as the salicylaldoxime 0.005g of chelating agent (E) in the resin solution of example 1.In addition operate equally with example 1, obtain conductive paste 7.Wherein, the compounding amount of salicylaldoxime is the ratio of 0.1 quality % with respect to copper particle (A-1).

(example 8)

Compounding is as the dimethyl oxalate 0.0215g of (F) composition in the resin solution of example 1.In addition operate equally with example 1, obtain conductive paste 8.The compounding amount of dimethyl oxalate is the ratio of 5 quality % with respect to the phenolic resins as (B) composition.

(example 9)

Except compounding 0.0215g formamide replaces the 0.0215g dimethyl oxalate, implement equally with example 8, obtain conductive paste 9.

(example 10)

The PEI salt of compounding 0.005g salicylaldoxime, 0.0215g dimethyl oxalate, 0.07g in the resin solution of example 1.In addition operate equally with example 1, obtain conductive paste 10.

(example 11)

The PEI salt of compounding 0.005g salicylaldoxime, 0.0215g dimethyl oxalate, 0.07g in the resin solution of example 2.In addition operate equally with example 2, obtain conductive paste 11.

(example 12)

The PEI salt of compounding 0.005g salicylaldoxime, 0.0215g dimethyl oxalate, 0.07g in the resin solution of example 3.In addition operate equally with example 3, obtain conductive paste 12.

(example 13)

The PEI salt of compounding 0.005g salicylaldoxime, 0.0215g dimethyl oxalate, 0.07g in the resin solution of example 4.In addition operate equally with example 4, obtain conductive paste 13.

(example 14)

The IRGANOX1076 of 0.0025g in the example 11 is replaced with the IRGANOX1135 of 0.0025g.In addition operate equally with example 11, obtain conductive paste 14.

(example 15)

The addition of IRGANOX1135 in the example 14 is made as 0.025g.In addition operate equally with example 14, obtain conductive paste 15.

(example 16)

In the resin solution of example 1, do not add IRGANOX1076.In addition operate equally with example 1, obtain conductive paste 16.

(example 17)

The IRGANOX1076 of 0.005g is replaced with the BHT (2,6-di-t-butyl-paracresol) of 0.005g.In addition operate equally with example 1, obtain conductive paste 17.Wherein, 2,6-di-t-butyl-paracresol is the compound shown in the following chemical formula.Can be found out obviously that by chemical formula this compound does not have the ester bond of containing group on 4 of phenyl ring, not belong to the aromatic compound (C) shown in the aforementioned formula (1).

[chemical formula 9]

(example 18)

The IRGANOX1076 of 0.005g is replaced with the IRGANOX1010 (BASF AG makes, four [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester) of 0.005g.In addition operate equally with example 1, obtain conductive paste 18.Wherein, the chemical formula of four [3-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester is as follows.Can be found out obviously that by chemical formula this compound does not have and contains the ester bond group shown in the aforementioned formula (2), does not belong to the aromatic compound (C) shown in the formula (1) on 4 of phenyl ring.

[Chemical formula 1 0]

(example 19)

The IRGANOX1076 of 0.005g is replaced with IRGANOX1098 (BASF AG's manufacturing, N, the N '-hexa-methylene two (3,5-di-t-butyl-4-hydroxyl-hydrocinnamamide) of 0.005g.In addition operate equally with example 1, obtain conductive paste 19.Wherein, N, the chemical formula of N '-hexa-methylene two (3,5-di-t-butyl-4-hydroxyl-hydrocinnamamide) is as follows.Can be found out obviously that by chemical formula this compound does not have the ester bond of containing group on 4 of phenyl ring, not belong to the aromatic compound (C) shown in the formula (1).

[Chemical formula 1 1]

(example 20)

The IRGANOX1076 of 0.005g is replaced with the IRGANOX1330 (BASF AG makes, 1,3,5-trimethyl-2,4,6-three (3,5-di-tert-butyl-4-hydroxyl benzyl) benzene) of 0.005g.In addition operate equally with example 1, obtain conductive paste 20.1,3,5-trimethyl-2,4, the chemical formula of 6-three (3,5-di-tert-butyl-4-hydroxyl benzyl) benzene is as follows.

[Chemical formula 1 2]

Wherein, R is 3 shown in the following chemical formula, the 5-di-tert-butyl-4-hydroxyl benzyl.

[Chemical formula 1 3]

Can be found out obviously that by aforementioned chemical formula this compound does not have the ester bond of containing group on 4 of phenyl ring, not belong to the aromatic compound (C) shown in the formula (1).

Then, by silk screen print method the conductive paste 1 ~ 20 that obtains in the example 1 ~ 20 is coated with into the wiring shape (band shape) of wide 1mm, thickness 20 μ m respectively at glass substrate, 130 ℃ of heating 10 minutes down, makes phenolic resin curing.Thus, form the substrate 1 ~ 20 of the band conducting film with conducting film 1 ~ 20 respectively.

Then, (Keithley company makes, the device name: Milli-Ohm HiTESTER) measure the resistance value of the conducting film 1 ~ 20 that obtains, obtain initial specific insulation (μ Ω cm) to use the resistance value meter.

In addition, the substrate 1 ~ 20 of the band conducting film that obtains in the example 1 ~ 20 is carried out the endurance test of thermal cycle.That is, the substrate 1 ~ 20 of band conducting film is being made as in-40 ℃ the groove of low temperature with being made as in 85 ℃ the groove of high temperature and keeping respectively 30 minutes, applying the thermal cycle that alternately applies thermal shock of 100 circulations.Then, after this endurance test, measure the resistance value of conducting film 1 ~ 20, obtain specific insulation.

With thus to initial specific insulation and the rate of change (climbing) of the specific insulation after the endurance test be shown in table 1.

[table 1]

As shown in Table 1, utilization at copper particle (A) with as the basis of the phenolic resins of heat reactive resin (B) on compounding the substrate 1 ~ 15 (example 1 ~ 15) that has the phenol hydroxyl and be formed with the band conducting film of conducting film 1 ~ 15 at the conductive paste 1 ~ 15 that 4 of phenyl ring have an aromatic compound that contains the ester bond group (C) shown in the aforementioned formula (2) at glass substrate in molecule is arranged, initial specific insulation is enough low, and the climbing of the specific insulation behind the thermal cycling test is suppressed in low-level.

Especially utilize on the basis of aforementioned aromatic compound (C) compounding to have as the PEI salt that contains the carboxylate (D) of amino macromolecular compound, chelating agent (E) with as pKa to be the whole conductive paste 10 ~ 15 of dimethyl oxalate of 1 ~ 4 organic acid ester (F) to be formed with the base material 10 ~ 15 (example 10 ~ 15) of the band conducting film of conducting film 10 ~ 15 at glass substrate, the climbing of the specific insulation behind the thermal cycling test is suppressed in extremely low-level, is below 6%.

With it relatively, utilize compounding to have to have the phenol hydroxyl in the molecule but on 4 of phenyl ring, do not have the base material 17 ~ 20 (example 17 ~ 20) of the band conducting film that the conductive paste 17 ~ 20 of the aromatic compound that contains the ester bond group shown in the aforementioned formula (2) obtains, the climbing of the specific insulation behind the thermal cycling test is high, be more than 100 ~ 500%, poor durability.

In addition, the base material 16 (example 16) of the band conducting film that the conductive paste 16 that utilizing does not have the aforementioned aromatic compound of compounding (C) obtains, the climbing height of the specific insulation behind the thermal cycling test is about 200%, poor durability.

Describe the present invention in detail or with reference to specific execution mode, but can not exceed the in addition various changes of the spirit and scope of the invention ground, correction, this is apparent for a person skilled in the art.

The application quotes its content herein as reference based on the Japanese patent application 2011-289692 of application on December 28th, 2011.

Utilizability on the industry

According to the present invention, can form the conducting film that specific insulation is low and the thermal shock that cold cycling etc. causes is had excellent durability.In addition, by using this conductive paste, can access the reliability height and the base material of the band conducting film that is suppressed because of the rising that forms the specific insulation that the oxidation overlay film causes.The base material of the band conducting film that obtains among the present invention can be used as electronic unit, printed circuit board (PCB) (printed circuit board (PCB)) etc. aptly.

Claims (18)

1. a conductive paste is characterized in that, it contains and has phenol hydroxyl and at least one in the molecule shown in copper particle (A), thermosetting resin (B) and the following general formula (1) and contain the aromatic compound (C) of ester bond group,

Symbol in the formula (1) is as follows,

R ₁: aliphatic alkyl or hydrogen atom,

R ₂: contain the ester bond group shown in aliphatic alkyl, hydrogen atom or the following formula (2),

R ₃: contain the ester bond group shown in the following formula (2),

R ₄: contain the ester bond group shown in aliphatic alkyl, hydrogen atom or the following formula (2),

R ₅: aliphatic alkyl or hydrogen atom,

In the formula (2), R ₆Be aliphatic alkyl, n is 1 ~ 4 integer.

2. conductive paste according to claim 1 is characterized in that, described aromatic compound (C) only has the described ester bond group that contains at 4 of phenyl ring.

3. conductive paste according to claim 1 and 2, wherein, with respect to the described copper particles of 100 mass parts (A), the content of described aromatic compound (C) is 0.005 ~ 0.5 mass parts.

4. according to each the described conductive paste in the claim 1 ~ 3, wherein, also contain the carboxylate (D) of the macromolecular compound that has primary amino radical in the molecule.

5. conductive paste according to claim 4, wherein, described macromolecular compound with primary amino radical is polymine or polyallylamine.

6. according to claim 4 or 5 described conductive pastes, wherein, the carboxylate of described (D) composition is formates.

7. according to each the described conductive paste in the claim 1 ~ 6, wherein, also contain chelating agent (E), described chelating agent (E) is by being the stability constant logK of the copper ion of 0.1mol/L with ionic strength down at 25 ℃ _CuBe that 5 ~ 15 compound forms.

8. conductive paste according to claim 7, wherein, described chelating agent (E) is for disposing the functional group (a) that comprises nitrogen-atoms and the aromatic compound of the functional group (b) that comprises the atom with lone electron pair except nitrogen-atoms at the ortho position of aromatic rings.

9. conductive paste according to claim 8, wherein, the nitrogen-atoms of the described functional group (a) of described chelating agent (E) clips two or three atoms with the atom with lone electron pair except nitrogen-atoms of described functional group (b) and is connected.

10. according to each the described conductive paste in the claim 7 ~ 9, wherein, described chelating agent (E) is for being selected from least a compound in the group of being made up of bigcatkin willow hydroximic acid, salicylaldoxime and o-aminophenol.

11. according to each the described conductive paste in the claim 1 ~ 10, wherein, also contain pKa and be 1 ~ 4 organic acid, ester or acid amides (F).

12. conductive paste according to claim 11, wherein, described organic acid ester or acid amides (F) are for being selected from least a in the group of being made up of formamide, gaultherolin, dimethyl oxalate, dimethyl malenate and dimethyl maleate.

13. according to claim 11 or 12 described conductive pastes, wherein, with respect to the described thermosetting resin (B) of 100 mass parts, the content of described organic acid ester or acid amides (F) is 0.5 ~ 15 mass parts.

14. according to each the described conductive paste in the claim 1 ~ 13, wherein, described thermosetting resin (B) is for being selected from least a in phenolic resins, melamine resin and the Lauxite.

15. according to each the described conductive paste in the claim 1 ~ 14, wherein, with respect to the described copper particle (A) of 100 mass parts, the content of described thermosetting resin (B) is 5 ~ 50 mass parts.

16. the base material with conducting film, it has conducting film at base material and forms, and described conducting film is that each the described conductive paste in the claim 1 ~ 15 is solidified to form.

17. the base material of band conducting film according to claim 16, wherein, the specific insulation of described conducting film is 1.0 * 10 ^-4Below the Ω cm.

18. the manufacture method with the base material of conducting film is characterized in that, be coated on each the described conductive paste in the claim 1 ~ 15 on the base material after, this conductive paste of heating makes its curing under the temperature of 150 ℃ of less thaies, forms conducting film.

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