JP2003054946A - Copper oxide powder, production method therefor, electrically conductive paste, ceramic wiring board and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems that, when electrically conductive paste containing CuO or Cu2 O powder to be reduced into Cu by burning in a reducing atmosphere is used, rapid deoxidization occurs on the burning in the reducing atmosphere, and therefore, cracks or peeling occur in an electrically conductive film and a via hole conductor formed thereby and ceramic material around them. SOLUTION: On copper oxide powder particles 7 contained in the electrically conductive paste and essentially consisting of CuO or Cu2 O, a surface layer part 9 containing at least one species selected from Si, Al2 O3 , Nb2 O5 , Ta2 O5 , ZrO2 , NiO, MgO, ZnO, SnO2 , Bi2 O3 , TiO2 and SiO2 is formed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a copper oxide powder suitably used for inclusion in a conductive paste, a method for producing the same, a conductive paste containing the copper oxide powder, and the conductive paste. The present invention relates to a ceramic wiring board configured by using the above and a manufacturing method thereof.

[0002]

2. Description of the Related Art Ceramic wiring boards are used for mounting various electronic components and for wiring these electronic components.
More specifically, it is used in package components that house semiconductor elements such as ICs and LSIs, and in hybrid integrated circuit devices that mount a plurality of types of electronic components. Further, the ceramic wiring board includes a single-layer structure and a multi-layer structure.

In a ceramic wiring board, a wiring conductor is usually formed by baking conductive paste containing conductive metal powder as a conductive component and kneading an organic vehicle composed of an organic binder and an organic solvent. To be done. In the wiring conductor provided inside the multilayered ceramic wiring board, the wiring conductor is formed by simultaneously firing the conductive paste in the firing step for obtaining the ceramic wiring board. Even the wiring conductor provided on the outer surface of the ceramic wiring board may be formed by firing the conductive paste at the same time as the firing step for obtaining the ceramic wiring board.

In such a ceramic wiring board,
As the size of the wiring, the density of wiring, and the speed and frequency of signals increase, wiring conductors are required to have lower electric resistance.

Therefore, copper (Cu) is advantageously used as a conductive component contained in the wiring conductor. Note that as the conductive metal having a low electric resistance, there are gold, silver, and the like in addition to copper, but it is particularly preferable to use copper from the viewpoint of cost.

[0006] As described above, copper is inexpensive and has low resistance, and since it is excellent in migration resistance, the interval between wiring conductors can be narrowed, and the small size of the ceramic wiring board as described above. It is a material suitable for high density and high density wiring, and is preferably used as a conductive component for a wiring conductor in a ceramic wiring board.

A ceramic wiring board having a multilayer structure in which copper is used as a wiring conductor is prepared from a conductive paste containing copper and a plurality of ceramic materials containing a ceramic material which can be sintered at a temperature lower than the melting point (1083 ° C.) of copper. Prepare a ceramic green sheet, provide a through hole for a via-hole conductor in the ceramic green sheet, if necessary, fill the through hole with a conductive paste, or have a predetermined pattern using the conductive paste. After forming a conductor film by applying a thick film forming method such as screen printing, stacking multiple ceramic green sheets, pressing and heating the resulting green laminate to remove the binder. Can be manufactured by firing and then firing.

In the above manufacturing method, the copper contained in the conductive paste undergoes volume expansion when oxidized,
Therefore, the wiring conductor formed by the conductive paste may peel off from the ceramic base side of the ceramic wiring board. To prevent this, a non-oxidizing atmosphere such as a reducing atmosphere is usually applied in the firing process. Has been done.

However, it was difficult to completely remove the organic components contained in the conductive paste and the ceramic green sheet by thermal decomposition by firing in a non-oxidizing atmosphere, and it was obtained. The density or strength of the ceramic wiring board may decrease.

To solve this problem, Japanese Patent Laid-Open No. 61-26293 proposes to use copper oxide as a conductive component contained in the conductive paste. According to this, in the firing process, first, the organic components are completely removed by firing in an oxidizing atmosphere, and then the firing is performed in a reducing atmosphere to reduce copper oxide to metallic copper (Cu). At the same time, the ceramic material is sintered.

However, in the above-mentioned method, since volume contraction occurs when copper oxide is reduced to metallic copper, the wiring conductor becomes undesirably thin and may be peeled from the ceramic substrate side or cracked. is there.

In order to solve this problem, Japanese Patent Laid-Open No. 11-6
In 6952, by adding a small amount of zirconium oxide to a conductive paste using copper oxide,
A technique for suppressing volume contraction when copper oxide is reduced to metallic copper has been proposed.

Further, in Japanese Laid-10-95686, JP-conductive component contained in the conductive paste is not limited to the case of copper oxide, but may also be a metallic copper, Al ₂
A technique for delaying the shrinkage start temperature in the temperature rising process in the firing process of the conductive paste by adding a metal oxide such as O ₃ , ZrO ₂ , NiO, MgO, ZnO, and SiO ₂ is described.

[0014]

However, the above-mentioned JP-A-11-66952 and JP-A-10-9 are mentioned above.
In the technique described in Japanese Patent No. 5686, when the conductive component contained in the conductive paste is copper oxide, in the low temperature region in the oxidizing atmosphere in the temperature increasing process in the firing process, the conductivity is reduced. Although it is possible to suppress the volume expansion of the conductive paste, deoxidation occurs when the copper oxide is reduced in the high temperature region in the reducing atmosphere before the sintering is achieved. Since it occurs suddenly from the inside, it may lead to a sudden increase in volume of the wiring conductor.

The above-mentioned phenomenon of volume increase when deoxidation occurs is caused by the inside of the copper oxide particles contained in the conductive paste. Appears.

On the other hand, in the high temperature region before sintering in the reducing atmosphere, the solvent in the organic vehicle contained in the ceramic green sheet and the conductive paste is in a state after being removed. The adhesive strength with the ceramic substrate is low, and the increase in volume of the wiring conductor as described above causes a serious problem that the wiring conductor is easily peeled off from the ceramic substrate. In particular, with respect to the wiring conductor formed on the outer surface of the ceramic wiring board, only one surface of the wiring conductor is adhered to the ceramic substrate, and therefore, it is extremely easy to peel off.

Further, in the firing method described in Japanese Patent Application Laid-Open No. 11-66952, it is necessary to control the firing atmosphere so that an oxidizing atmosphere is used in the low temperature region and a reducing atmosphere is used in the high temperature region. There is also a problem that the firing furnace used for firing needs to have a special function capable of such control, and the firing furnace becomes expensive.

Therefore, an object of the present invention is to provide a conductive paste which can solve the above problems.

Another object of the present invention is to provide a copper oxide powder used in the above-mentioned conductive paste and a method for producing the same.

Still another object of the present invention is to provide a method for manufacturing a ceramic wiring board which is carried out by using the above-mentioned conductive paste, and a ceramic wiring board obtained by this manufacturing method.

[0021]

First, the guide according to the present invention will be described.
The copper oxide powder contained in the electroconductive paste is CuO or
Cu₂O as a main component, Si, Al₂O₃, Nb
₂O_Five, Ta₂O_Five, ZrO ₂, NiO, MgO, Zn
O, SnO₂, Bi₂O₃, TiO₂And SiO₂Or
Particles having a surface layer portion containing at least one selected from
It is characterized by being composed of.

The present invention is also directed to a method for producing a copper oxide powder as described above.

The method for producing a copper oxide powder according to the present invention is, in the first embodiment, a step of producing a slurry in which CuO or Cu ₂ O is dispersed, and a step of adding S to the slurry.
i, Al, Nb, Ta, Zr, Ni, Mg, Zn, S
adding a monomer containing at least one of n, Bi and Ti and a polymerization initiator, obtaining a polymer by polymerizing a monomer in a slurry, and removing a dispersion medium from the slurry. Obtaining a polymer-coated CuO or Cu ₂ O powder,
And heat-treating the CuO or Cu ₂ O powder covered with the polymer.

The second embodiment of the method for producing a copper oxide powder according to the present invention is CuO or Cu ₂ O powder and Si, Al, Nb, Ta, Zr, Ni, Mg, Z.
A step of preparing a slurry in which a compound containing at least one of n, Sn, Bi and Ti is dispersed, and a dispersion medium is removed from the slurry to obtain CuO or Cu ₂ O powder covered with the above compound. It is characterized by comprising a step and a step of heat-treating CuO or Cu ₂ O powder covered with this compound.

In the third embodiment of the method for producing a copper oxide powder according to the present invention, with respect to CuO or Cu ₂ O powder, Si, Al, Nb, Ta, Zr, Ni, Mg,
It is characterized by including a step of spraying a solution containing at least one of Zn, Sn, Bi and Ti, and a step of drying CuO or Cu ₂ O powder to which this solution is applied.

The conductive paste according to the present invention is produced by using such a copper oxide powder. That is, the conductive paste according to the present invention contains a copper oxide powder containing CuO or Cu ₂ O as a main component and an organic vehicle, and at least a part of particles constituting the copper oxide powder is Si,
Al ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , ZrO ₂ , Ni
O, MgO, ZnO, SnO ₂ , Bi ₂ O ₃ , TiO ₂
And a surface layer portion containing at least one selected from SiO ₂ .

The copper oxide powder is 0.1 to 15.0 μm.
It is preferable to have an average particle size in the range of m.

The maximum layer thickness of the surface layer portion is 0.01 to
It is preferably in the range of 10.0 μm.

Further, the conductive paste according to the present invention is
You may further contain the copper powder which has Cu as a main component.

The present invention is also directed to a method for manufacturing a ceramic wiring board, which is carried out using the above-mentioned conductive paste, and a ceramic wiring board obtained by this manufacturing method.

In the first embodiment, the method for manufacturing a ceramic wiring board according to the present invention includes a step of preparing the above-mentioned conductive paste and a ceramic material which can be sintered at a temperature lower than the melting point of copper. A step of preparing a raw ceramic compact, a step of applying a conductive paste onto the raw ceramic compact, and a reduction of the raw ceramic compact together with the conductive paste at a temperature in the range of 800 to 1000 ° C. And a step of firing in a natural atmosphere.

In the second embodiment, the method for manufacturing a ceramic wiring board according to the present invention includes the step of preparing the above-mentioned conductive paste and a ceramic material which can be sintered at a temperature lower than the melting point of copper. A step of preparing a plurality of ceramic green sheets, a step of forming a conductive film made of a conductive paste on a specific ceramic green sheet, a through hole is formed in the specific ceramic green sheet, and the conductive paste is filled in the through hole. The step of forming a via-hole conductor, the step of producing a green laminate by laminating a plurality of ceramic green sheets, and the green laminate at a temperature in the range of 800 to 1000 ° C. And a step of firing in a reducing atmosphere.

[0033]

1 is a sectional view schematically showing a ceramic wiring substrate 1 having a multilayer structure obtained by applying a manufacturing method according to an embodiment of the present invention.

The ceramic wiring board 1 has a laminated structure composed of a plurality of laminated ceramic layers 2.

Inside the ceramic wiring board 1, some internal conductor films 3 extending along a specific interface between the ceramic layers 2 and some internal conductor films 3 extending so as to penetrate the specific ceramic layer 2 in the thickness direction. A via hole conductor 4 is provided.

On the outer surface of the ceramic wiring board 1, several external conductor films 5 are provided.

Wiring conductors such as the inner conductor film 3, the via-hole conductors 4 and the outer conductor film 5 interconnect circuit elements formed on the ceramic wiring board 1, and particularly, the inner conductor film 3 and the via-hole conductors. 4, a passive element such as a capacitor or an inductor is formed inside the ceramic wiring board 1, and another external conductor film 5 is mounted on the outer surface of the ceramic wiring board 1. It serves as a terminal electrode for an electronic component or as a terminal electrode for connection to a mother board on which the ceramic wiring board 1 is mounted.

The ceramic wiring board 1 having such a multilayer structure can be manufactured as follows.

First, a conductive paste for forming wiring conductors such as the inner conductor film 3, the via-hole conductor 4 and the outer conductor film 5 is prepared. This conductive paste is C
It contains copper oxide powder containing uO or Cu ₂ O as a main component, and an organic vehicle composed of an organic binder and an organic solvent. At least some of the particles constituting the above-mentioned copper oxide powder have a cross-sectional structure as shown in FIG.

That is, the particles 7 constituting the copper oxide powder
Is CuO or Cu₂Copper oxide centered mainly on O
In addition to having the part 8, Si, Al₂O₃, Nb
₂O_Five, Ta₂O_Five, ZrO₂, NiO, MgO, Zn
O, SnO₂, Bi₂O₃, TiO ₂And SiO₂Or
Equipped with a surface layer portion 9 containing at least one selected from
It

The particles 7 of the copper oxide powder having the surface layer portion 9 as shown in FIG. 2 described above can be manufactured, for example, by the following method.

In the first manufacturing method, CuO or Cu _{2 is used.}
A step of producing a slurry in which O powder is dispersed, and Si, Al, Nb, Ta, Zr, Ni, M
a step of adding a monomer containing at least one of g, Zn, Sn, Bi and Ti and a polymerization initiator, a step of obtaining a polymer by polymerizing a monomer in a slurry, and a step of removing a dispersion medium from the slurry. A step of obtaining CuO or Cu ₂ O powder covered with the polymer, and CuO or Cu ₂ O covered with the polymer.
And heat treating the powder.

In the second manufacturing method, CuO or Cu _{2 is used.}
O powder and Si, Al, Nb, Ta, Zr, Ni,
A step of preparing a slurry in which a compound containing at least one of Mg, Zn, Sn, Bi and Ti is dispersed, and CuO or Cu ₂ O covered with the above compound by removing the dispersion medium from the slurry. A step of obtaining a powder and a step of heat-treating CuO or Cu ₂ O powder covered with this compound are carried out.

In the third manufacturing method, CuO or Cu _{2 is used.}
For O powder, Si, Al, Nb, Ta, Zr, N
at least one of i, Mg, Zn, Sn, Bi and Ti
The step of spraying the solution containing the seed and the step of drying the CuO or Cu ₂ O powder provided with this solution are carried out.

On the other hand, a plurality of ceramic green sheets containing a ceramic material that can be sintered at a temperature lower than the melting point of copper are prepared. These ceramic green sheets are shown in Figure 1.
Which should be the ceramic layer 2 shown in
A slurry obtained by mixing a ceramic material powder sinterable at a temperature lower than the melting point of copper, an organic binder, a plasticizer, and an organic solvent is formed into a sheet on a carrier film by a doctor blade method, and this is formed. It can be obtained by drying.

Next, on a specific one of the plurality of ceramic green sheets obtained as described above,
The inner conductor film 3 or the outer conductor film 5 is formed by applying the above-described conductive paste by a method such as a printing method.

Further, a specific one of the plurality of ceramic green sheets is provided with a through hole, and the through hole is filled with a conductive paste by applying a printing method or the like, whereby the via hole conductor 4 is formed. Is formed.

Next, a plurality of ceramic green sheets are laminated and then pressed in the laminating direction to produce a raw laminate in a raw state. In addition, the outer conductor film 5 may be formed by applying a conductive paste by printing, for example, after the raw laminate is prepared in this way.

Next, the green laminate is 800 to 1000 ° C.
And firing in a reducing atmosphere at a temperature in the range.
As a result, the ceramic green sheet and the conductive paste are sintered, and as a result, the ceramic wiring board 1 as shown in FIG. 1 is obtained.

Although it is not essential to control the oxidizing atmosphere in the low temperature region in the firing step, for example, when the amount of the organic binder contained in the ceramic green sheet is relatively large, the low temperature in the firing step is used. An oxidizing atmosphere may be used in the region.

In the firing process as described above, the conductive paste is
CuO or Cu contained in the host ₂O is the main component
As shown in FIG. 2, the copper oxide powder particles 7 are made of Si or the like.
Since the surface layer portion 9 containing the inorganic substance is formed, the reducing atmosphere is reduced.
CuO or Cu depending on the atmosphere ₂Brought along with reduction of O
The deoxidation that is performed can be caused gently. Well
In addition, the inorganic substance such as Si contained in the surface layer portion 9 is
Green sheet or ceramic contained in ceramic layer 2
Internal conductor film because it easily gets wet with the glass component in the mix
3, the via-hole conductor 4 and the outer conductor film 5 and the ceramic
Mick layer 2 adheres well, and the internal conductor film during firing
3, via hole conductor 4 and outer conductor film 5
It is possible to prevent peeling from the Mick layer 2
It

The particles 7 of the copper oxide powder contained in the conductive paste preferably have an average particle diameter in the range of 0.1 to 15.0 μm.

The average particle size of the copper oxide powder particles 7 is 0.1.
If it is less than μm, aggregation of the inorganic substances contained in the surface layer portion 9 progresses, and the particles 7 of the copper oxide powder are separated in the conductive paste, and as a result, it becomes difficult to wet the glass component in the ceramic. Therefore, the adhesive strength of each of the inner conductor film 3, the via-hole conductor 4, and the outer conductor film 5 provided by the conductive paste to the ceramic layer 2 may be reduced.

On the contrary, when the average particle size of the copper oxide powder particles 7 becomes larger than 15.0 μm, deoxidation at the time of reduction rapidly occurs, so that the inner conductor film 3, the via-hole conductor 4 and the outer conductor film 5 are not removed. Each has a risk of coming off the ceramic layer 2. Empirically, the upper limit of the amount of expansion due to deoxidation is 5.0 times or less the original volume, and each of the inner conductor film 3, the via-hole conductor 4 and the outer conductor film 5 and the ceramic layer 2 It is said that there is no peeling due to the adhesive force between the two. As described above, by setting the average particle diameter of the copper oxide powder particles 7 to 15.0 μm or less, the expansion amount due to deoxidation can The volume can be 5.0 times or less.

The maximum layer thickness of the surface layer portion 9 formed on the copper oxide powder particles 7 is preferably selected in the range of 0.01 to 10.0 μm.

If the maximum layer thickness of the surface layer portion 9 is less than 0.01 μm, it becomes difficult to gently cause deoxidation due to the reduction of the copper oxide central portion 8 containing CuO or Cu ₂ O as a main component. , Deoxidation may occur rapidly with the start of the reduction reaction.

On the other hand, the maximum layer thickness of the surface layer portion 9 is 10.0 μm.
If larger than m, CuO or Cu ₂O is the main component
The reduction reaction in the copper oxide central portion 8 is less likely to occur, and the firing
Later, CuO or Cu₂O is fully reduced to Cu
Therefore, the inner conductor film 3 and the via hole conductor are not formed.
The electric resistance of the body 4 and the outer conductor film 5 may increase.
It Further, particularly in the outer conductor film 5, the surface layer portion 9 is
Inorganic substances contained in the product became exposed on the surface.
Therefore, the solder wettability of the outer conductor film 5 may be extremely deteriorated.
is there.

The maximum layer thickness of the surface layer portion 9 as described above is more preferably selected in the range of 0.1 to 3.0 μm.

When the maximum layer thickness of the surface layer portion 9 is selected within the above-mentioned more preferable range, the inorganic substance contained in the surface layer portion 9 reacts with the glass component in the ceramic during firing to increase the fluidity and the degree of diffusion. Due to the difference, the inorganic substances diffuse into the glass component, and at the same time, an appropriate amount of the glass component permeates between the particles 7 of the copper oxide powder. As a result, each of the inner conductor film 3, the via-hole conductor 4 and the outer conductor film 5 has a ceramic layer 2 with a slight amount of glass interposed.
And the effect of firmly adhering is enhanced.

In the conductive paste, copper powder containing Cu as a main component may be further added for the purpose of controlling shrinkage temperature characteristics and improving printability or bonding strength, and a suitable resin or glass may be added. Further, other inorganic substances may be further added, or the surface treatment of the copper oxide powder may be performed with these.

Although the embodiment of the present invention has been described with respect to the multilayered ceramic wiring board 1, the present invention can be applied to a single-layered ceramic wiring board.

[0062]

EXAMPLES A method for manufacturing a ceramic wiring board according to the present invention will be described below based on more specific examples.

1. Preparation of Conductive Paste To CuO or Cu ₂ O powder, anionic surfactant such as polymer carboxylic acid type surfactant and xylene-toluene mixed solvent having a weight ratio of 1: 1 were added and mixed and crushed. By performing the treatment, a slurry in which CuO or Cu ₂ O powder is suspended is obtained.

Next, titanium methacrylate, titanium isoproxide, niobium acrylate or niobium hydroxide, etc. are added to this slurry, and benzoyl peroxide is added as a polymerization initiator, and the mixture is stirred at a temperature of 65 ° C. While carrying out a polymerization reaction, a polymer is obtained.

Next, the polymer and CuO contained therein
Alternatively, the Cu ₂ O powder is transferred to a rotary evaporator or the like, and the temperature is reduced to 70 ° C. and the pressure is reduced to 6.7 × 10 ³ Pa.
Drying is performed while removing the xylene-toluene mixed solvent, and the obtained dry powder is heat-treated at 500 ° C.

As a result, TiO ₂ or Nb ₂ O ₅
It is possible to obtain CuO or Cu ₂ O powder in which the surface layer portion including the above is formed.

Instead of the method described above, the following method may be applied.

An anionic surfactant such as a polymeric carboxylic acid type surfactant and pure water are added to CuO or Cu ₂ O powder, and mixed and crushed to obtain Cu.
A slurry in which O or Cu ₂ O powder is suspended is obtained.

To this slurry, titanyl nitrate, niobium citrate or the like is added and mixed / dispersed.

Next, the above-mentioned mixed and dispersed slurry is transferred to a rotary evaporator or the like and heated to a temperature of 55.
Water was removed under reduced pressure at 6.7 × 10 ³ Pa at
After obtaining the dry powder, the dry powder is heat-treated at 500 ° C. to obtain CuO or Cu ₂ O powder having a surface layer portion containing TiO ₂ or Nb ₂ O ₅ .

Further, the following method may be adopted.

A slurry is obtained by adding titanium nonadecanoate or niobium octylate to CuO or Cu ₂ O powder and subjecting it to dispersion treatment.

Next, this slurry is dried by a well-known spray drying method to obtain a dry powder.

Next, the dry powder is heat-treated at 500 ° C. to obtain CuO or Cu ₂ O powder having a surface layer portion containing TiO ₂ or Nb ₂ O ₅ .

Further, the following method may be adopted.

By adding and mixing water and aluminum sulfate to CuO or Cu ₂ O powder,
Obtain a slurry.

Next, the slurry is sprayed in a spray dryer to perform surface treatment and drying, whereby CuO or Cu ₂ O powder having a surface layer portion containing Al ₂ O ₃ can be obtained.

Further, the following method may be adopted.

15 kg / cm ² at a temperature of 150 ° C.
Cu in a high temperature air mill (impact crusher) that maintains the air flow of
Inject O or Cu ₂ O powder, spray 50% concentration ethyl silicate aqueous solution from the nozzle, and
By performing surface treatment and pulverization of ₂ O powder, S
It is possible to obtain CuO or Cu ₂ O powder in which the surface layer portion containing i is formed. In this case, by spraying aluminum sulfate, the surface layer portion containing Si and Al ₂ O ₃ can be formed into CuO or Cu ₂ O powder.

Obtained by any of the above methods
Si, Al₂O₃, Nb₂O _Five, Ta₂O_Five, Z
rO₂, NiO, MgO, ZnO, SnO₂, Bi₂O
₃, TiO₂And SiO₂At least one selected from
An average particle size of 0.1 to 15.0 having a surface layer portion containing seeds
μm, CuO powder, Cu₂O powder or CuO-
Cu₂O mixed powder and organic binder
Add a predetermined amount of organic vehicle consisting of agent, and mix with a stirring and crushing machine.
By mixing and kneading with 3 rolls and 3 rolls,
Obtain an electrically conductive paste.

At this time, it is preferable that the CuO powder or the Cu ₂ O powder has no coarse powder or extremely agglomerated powder, and the maximum coarse particles after forming into a paste is 50 μm or less.

The organic binder that constitutes the organic vehicle is not particularly limited, but, for example, ethyl cellulose, acrylic resin, polyvinyl butyral, methacrylic resin or the like can be used. Further, the solvent constituting the organic vehicle is not particularly limited, but for example, terpineol, butyl carbitol, butyl carbitol acetate, alcohols and the like can be used. In addition, various dispersants and activators may be added if necessary.

The viscosity of the conductive paste is selected, for example, from 50 to 700 Pa · s ⁻¹ in consideration of printability.

2. Preparation of Ceramic Green Sheet For example, a mixture of powders of barium oxide, silicon oxide, alumina, calcium oxide and boron oxide, an organic binder made of polyvinyl butyral, a plasticizer made of di-n-butyl phthalate, and toluene. And an organic solvent consisting of isopropylene alcohol are mixed to obtain a slurry.

Next, this slurry was formed into a sheet on a carrier film by the doctor blade method,
Dry to obtain a ceramic green sheet.

As the above-mentioned organic binder, plasticizer and organic solvent, those other than the specific examples may be used.

Further, promotion of sintering, control of shrinkage behavior,
For the purpose of improving strength and controlling electrical characteristics,
Other inorganic compound or glass may be added to the slurry, or a metal may be added within a range that does not impair the electrical insulation property, and an antistatic agent, a tackifier, or the like may be added.

3. Formation of Conductor Film and Via-Hole Conductor On a specific one of the ceramic green sheets obtained as described above, the conductive paste prepared as described above is applied to form a conductor film. In applying the conductor film, a printing method such as screen printing is applied, and the conductor film is applied in a desired pattern.

The conductor film may be an inner conductor film located inside the obtained multilayered ceramic wiring board or an outer conductor film formed on the outer surface of the ceramic wiring board.

Further, a through hole having a diameter of 0.03 to 0.5 mm is formed in a specific one of the ceramic green sheets by laser processing or punch processing.
This through hole is not limited to a circular shape and may be any polygonal shape.

Next, a printing method such as screen printing is applied to the above-mentioned through holes to fill the above-mentioned conductive paste.

4. Lamination and Firing Next, a plurality of ceramic green sheets having conductor films and via-hole conductors formed thereon are laminated as described above, and the temperature is 25 to 80 ° C. and the pressure is 200 to 1800 kg / cm ^2.
The raw laminate is prepared by pressing under the conditions of.

Next, this raw laminate is used for 0.1 to 30 p.
Firing is performed in a reducing atmosphere controlled to have an oxygen concentration of pm, for example, at a temperature of 980 ° C. and a holding time of 1 hour.

In this way, a multilayer ceramic wiring board is obtained.

[0095]

[Experimental Example] Next, the following experiment was conducted to evaluate the conductive paste containing the copper oxide powder according to the present invention.

With respect to 100.0 g of CuO powder and / or Cu ₂ O powder, 0.2 g of anionic surfactant (polymeric carboxylic acid type surfactant) in terms of active ingredient,
200 g xylene-toluene mixed solvent (weight ratio 1:
1) and partially stabilized zirconia with a diameter of 5 mm (PS
Z) Add 300 g of boulders, put them in a polyethylene pot, and mix and crush for 16 hours to obtain CuO.
A slurry in which the powder and / or Cu ₂ O powder was suspended was obtained.

Next, this slurry was mixed with 1000
The mixture was transferred to a cc separable flask, and 1.50 g of titanium methacrylate as a fatty acid metal salt having an unsaturated bond in terms of titanium oxide was added. Furthermore, methacrylate 10
After adding 0.1 part by weight of benzoyl peroxide as a polymerization initiator to 0 part by weight, a separable flask was set in a mantle heater, a condenser was attached, cooling water was flowed, and a temperature of 65 ° C was set. Polymerization reaction was carried out for 16 hours while stirring with to obtain a polymer of titanium methacrylate.

After the completion of the polymerization reaction, the mixture was cooled to room temperature, the obtained slurry was transferred to a rotary evaporator, and the temperature was adjusted to 7
Under a reduced pressure condition of 0 ° C. and 6.7 × 10 ³ Pa, xylene-
The toluene mixed solvent was removed and drying was performed to obtain a dry powder.

Next, the obtained dry powder is heat-treated at 500 ° C. to form CuO having a surface layer portion containing TiO _2.
A powder and / or a Cu ₂ O powder was obtained.

The CuO powder and / or Cu ₂ O powder obtained through the above operations correspond to samples 87 to 89 in Table 4.

In order to obtain the samples shown in each of Tables 1 to 3 and the remaining samples of Table 4, the same operation was carried out, and Si, Al ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , Zr
O ₂ , NiO, MgO, ZnO, SnO ₂ , Bi ₂ O ₃
And Cu having a surface portion containing SiO ₂ and SiO ₂ respectively.
O powder and / or Cu ₂ O powder was obtained.

In Tables 1 to 4, the C used was
The average particle size of each of the uO powder and the Cu ₂ O powder is shown, and the maximum layer thickness of the surface layer portion is also shown.

In addition, in Tables 1 to 4, for the samples containing both CuO powder and Cu ₂ O powder, the mixing ratio of CuO powder / Cu ₂ O powder was 1/1.

[0104]

[Table 1]

[0105]

[Table 2]

[0106]

[Table 3]

[0107]

[Table 4]

Next, an acrylic resin as an organic binder and butyl carbitol as an organic solvent were added to the CuO powder and / or Cu ₂ O powder according to each sample shown in Tables 1 to 4 and kneaded. By doing so, a conductive paste was prepared. The amount of the organic binder in this conductive paste was 18% by weight with respect to the CuO powder and / or the Cu ₂ O powder.

On the other hand, a mixture of powders of barium oxide, silicon oxide, alumina, calcium oxide and boron oxide, an organic binder made of polyvinyl butyral, a plasticizer made of di-n-butyl phthalate, and toluene and isobutane. A slurry was prepared by mixing with an organic solvent composed of propylene alcohol.

Next, this slurry was formed into a sheet on a carrier film by a doctor blade method and dried to prepare a ceramic green sheet having a thickness of 125 μm.

Next, laser processing was applied to predetermined positions of the above-mentioned ceramic green sheets to form through holes for via-hole conductors.

Next, using the above-mentioned conductive paste,
This was filled into a through hole to form a via hole conductor, and a conductor film having a dimension of 2 mm in length and width and a thickness of about 15 μm after firing was formed on the ceramic green sheet. Then, seven such ceramic green sheets are laminated under pressure and then at a temperature of 80 ° C.
A green laminate was produced by pressing under a pressure of 200 kg / cm ² .

Next, the raw laminate was heated at a temperature of 98 in a reducing atmosphere set to an oxygen concentration of 10 ppm.
Firing was performed under firing conditions of holding at 0 ° C. for 1 hour to obtain a ceramic wiring board for evaluation related to each sample.

The following evaluation was performed on the obtained ceramic wiring board for evaluation.

First, the surface of the conductor film in the ceramic wiring board according to each sample is visually observed with a binocular microscope with a magnification of 20 to 40, and defects such as peeling or cracks in the conductor film, the via-hole conductor or the periphery thereof are observed. The presence or absence was evaluated.

Next, with respect to the sample in which the above-mentioned defects such as peeling and cracks did not occur, the
Immerse in a 25 ° C. eutectic solder (63Sn-37Pb) bath for 5 minutes while rocking, and then observe the surface of a 2 mm square conductor film with a binocular microscope with a magnification of 20 to 40 times.
The ratio of the solder wetted area to the surface area of the conductor film was obtained, and it was evaluated whether the solder wettability was good (◯) or bad (×).

The above evaluation results are also shown in Tables 1 to 4.

In Tables 1 to 4, sample numbers marked with * are outside the scope of the present invention.
Further, a symbol with a symbol Δ is within the scope of the present invention, but indicates that some inconvenience occurred because the preferred specific conditions in the present invention were not satisfied.

As can be seen from the above experimental results, the CuO powder and / or C contained in the conductive paste was
The maximum layer thickness of the surface layer portion formed on the u ₂ O powder is 0.01
In the samples having a maximum layer thickness of 0.00 μm, that is, in the samples in which the surface layer portion was not formed, such as the samples 11 and 59 in this experimental example, the conductor film was peeled from the ceramic surface and was not present in the via-hole conductor. As a result, cracks occurred in the ceramic around it.

The maximum layer thickness of the surface layer is 10.0 μm.
In the larger samples 17 and 65, CuO was not sufficiently reduced in the conductor film and the via-hole conductor, so that the solder wettability was extremely deteriorated. Although not included in the samples shown in Tables 1 to 4, even in the sample containing Cu ₂ O powder, when the maximum layer thickness exceeds 10.0 μm, Cu ₂ O is not sufficiently reduced and the solder wettability is reduced. Has been confirmed to be extremely bad.

In the conductive paste, CuO
When only the powder is contained, Sample 1 in which the average particle diameter of the CuO powder is less than 0.1 μm, or when both the CuO powder and the Cu ₂ O powder are both contained, In Sample 28 having an average particle size of less than 0.1 μm, Si contained in the surface layer agglomerates, Si is exposed on the surface of the conductor film, cracks are generated, and solder wettability is also poor. Cracks also occurred in the via-hole conductor.

In the conductive paste, CuO
Powders and Cu ₂ O powders only, samples 10 and 27 having an average particle size of such CuO powder or Cu ₂ O powder larger than 15.0 μm, and CuO powder and Cu ₂ O powder If both are included, the average particle size of both is 15.0 μm.
In the larger sample 52, peeling occurred in the conductor film, and cracks occurred in the ceramic around the via-hole conductor.

In the conductive paste, CuO
In the case where both the powder and the Cu ₂ O powder were included, and the average particle size of one was larger than 15.0 μm and the average particle size of the other was smaller than 0.1 μm, the conductor film was cracked. Occurred, and cracks occurred in the via-hole conductor.

On the other hand, the conductive paste contains only one of CuO powder and Cu ₂ O powder and has an average particle diameter in the range of 0.1 to 15.0 μm. When both Cu ₂ O powders are included, at least one of them has an average particle size of 0.1 to 0.1
Samples 2 to 9, 12 to 1 having a maximum layer thickness of 0.01 to 10.0 μm in the range of 15.0 μm
6, 18-26, 29-31, 33-47, 49-5
In Nos. 1, 53 to 58, 60 to 64, and 65 to 92, the conductor film and the via-hole conductor did not peel or crack, and the solder wettability was good.

[0125]

As described above, according to the present invention, Cu
O and Cu ₂ O as main components, Si, Al ₂ O ₃ , N
b ₂ O ₅ , Ta ₂ O ₅ , ZrO ₂ , NiO, MgO, Z
nO, SnO ₂ , Bi ₂ O ₃ , TiO ₂ and SiO ₂
Provided is a copper oxide powder composed of particles having a surface layer portion containing at least one selected from the following. According to a conductive paste containing this copper oxide powder and an organic vehicle, in a reducing atmosphere, CuO or C
It is possible to gently generate deoxidation when u ₂ O is reduced.

Therefore, it is possible to suppress the volume expansion of the conductor film or the via-hole conductor constituted by the above-mentioned conductive paste, and at the same time, the inorganic substance such as Si contained in the surface layer portion as described above is the glass in the ceramic. Since it is easy to get wet with the components, it is possible to prevent cracks from occurring in the conductor film or the via-hole conductor during firing, and to prevent peeling between the conductor film or the via-hole conductor and the ceramic.

Therefore, by using such a conductive paste, a ceramic wiring board can be manufactured with stable quality and at a low cost.

In the conductive paste according to the present invention,
When the copper oxide powder has an average particle size in the range of 0.1 to 15.0 μm, it is possible to more reliably prevent cracks and peeling as described above from occurring, and it is possible to form the formed conductor film. It is possible to maintain good solder wettability.

When the maximum layer thickness of the surface layer portion of the copper oxide powder is in the range of 0.01 to 10.0 μm, it is possible to more reliably prevent the above-mentioned cracks and peeling from occurring and to reduce the reduction. In firing in a sexual atmosphere,
CuO or Cu ₂ O can be sufficiently reduced.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a ceramic wiring board 1 having a multilayer structure obtained by applying a manufacturing method according to an embodiment of the present invention.

FIG. 2 is a sectional view schematically showing particles 7 of oxide powder contained in the conductive paste according to the present invention.

[Explanation of symbols]

1 Ceramic wiring board 2 ceramic layers 3 Internal conductor film 4 Via hole conductor 5 External conductor film 7 Copper oxide powder particles 8 Copper oxide center 9 Surface layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/46 H05K 3/46 HS (72) Inventor Mitsuyoshi Nishide 2 26- Tenjin, Nagaokakyo, Kyoto Prefecture No. 10 F-term in Murata Manufacturing Co., Ltd. (reference) 4E351 AA07 BB01 BB31 CC12 CC31 CC35 DD04 DD52 DD55 EE11 GG09 GG15 5E343 AA02 AA23 BB24 BB72 BB75 DD03 ER38 GG39 GG02 GG18 GG24 GG18 GG24 GG18 GG18 GG04 EE18 GG08 GG09 HH11 HH32 5G301 DA23 DD01

Claims (12)

[Claims] 1. An alloy containing CuO or Cu ₂ O as a main component and S
i, Al ₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , ZrO ₂ ,
NiO, MgO, ZnO, SnO ₂ , Bi ₂ O ₃ , Ti
A copper oxide powder contained in a conductive paste, which is composed of particles having a surface layer portion containing at least one selected from O ₂ and SiO ₂ . 2. The method for producing a copper oxide powder according to claim 1, wherein a step of preparing a slurry in which CuO or Cu ₂ O powder is dispersed, and Si, Al, Nb, Ta are added to the slurry. , Zr, N
at least one of i, Mg, Zn, Sn, Bi and Ti
A step of adding a monomer containing a seed and a polymerization initiator, a step of polymerizing the monomer in the slurry to obtain a polymer, and a step of removing a dispersion medium from the slurry to cover the polymer with the polymer. a step of obtaining the CuO or Cu ₂ O powder was cracking, and a step of heat treating the CuO or Cu ₂ O powder covered with the polymer, the production method of the copper oxide powder. 3. The method for producing a copper oxide powder according to claim 1, wherein CuO or Cu ₂ O powder and Si, Al, Nb,
Ta, Zr, Ni, Mg, Zn, Sn, Bi and Ti
A step of preparing a slurry in which a compound containing at least one of the above is dispersed; a step of removing the dispersion medium from the slurry to obtain the CuO or Cu ₂ O powder covered with the compound; And a step of heat-treating the covered CuO or Cu ₂ O powder. 4. The method for producing a copper oxide powder according to claim 1, wherein Si, Al, N is added to CuO or Cu ₂ O powder.
b) spraying a solution containing at least one of Ta, Zr, Ni, Mg, Zn, Sn, Bi and Ti, and drying the CuO or Cu ₂ O powder to which the solution is applied , A method for producing a copper oxide powder. 5. A copper oxide powder containing CuO or Cu ₂ O as a main component and an organic vehicle, wherein at least some of the particles constituting the copper oxide powder are Si, Al.
₂ O ₃ , Nb ₂ O ₅ , Ta ₂ O ₅ , ZrO ₂ , NiO,
A conductive paste having a surface layer portion containing at least one selected from MgO, ZnO, SnO ₂ , Bi ₂ O ₃ , TiO ₂ and SiO ₂ . 6. The copper oxide powder is 0.1 to 15.0.
The conductive paste according to claim 5, having an average particle size in the range of μm. 7. The maximum layer thickness of the surface layer portion is 0.01 to 1.
The conductive paste according to claim 5, which is in the range of 0.0 μm. 8. The conductive paste according to claim 5, further comprising copper powder containing Cu as a main component. 9. A step of preparing the conductive paste according to claim 5, and a step of preparing a green ceramic compact containing a ceramic material that can be sintered at a temperature lower than the melting point of copper. Applying the conductive paste onto the green ceramic compact, and firing the raw ceramic compact together with the conductive paste in a reducing atmosphere at a temperature in the range of 800 to 1000 ° C. A method of manufacturing a ceramic wiring board, comprising: 10. A ceramic wiring board obtained by the manufacturing method according to claim 9. 11. A step of preparing the conductive paste according to claim 5, and a step of preparing a plurality of ceramic green sheets containing a ceramic material that can be sintered at a temperature lower than the melting point of copper. A via hole conductor is formed by forming a conductor film made of the conductive paste on the specific ceramic green sheet, and forming a through hole in the specific ceramic green sheet and filling the through hole with the conductive paste. And a step of forming a raw laminate by laminating a plurality of the ceramic green sheets, and the raw laminate in a reducing atmosphere at a temperature in the range of 800 to 1000 ° C. A method of manufacturing a ceramic wiring board, comprising: 12. A ceramic wiring board obtained by the manufacturing method according to claim 11.