JP2002176236A - Composition for via hole conductor and multilayer ceramic substrate and its producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a via hole conductor in which protrusion at a part of a via hole conductor or cracking of a ceramic layer or the via hole conductor can be prevented at the time of producing a multilayer ceramic substrate comprising a plurality of ceramic layers containing BaO-Al2O3-SiO2 mixture ceramic and the via hole conductors penetrating specified ceramic layers. SOLUTION: The composition of a via hole conductor principally comprises at least one kind selected from Cu, CuO, Cu2O, Cu-CuO compound, Cu-Cu2O compound and CuO-CuO compound, and is added with 0.5-30.0 wt.% of an inorganic bore forming agent composed of tungsten and/or inorganic boron compound having a mean particle size of 0.1-30.0 μm for the total weight of the principal component and the inorganic bore forming agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for a via-hole conductor, a multilayer ceramic substrate using the same, and a method of manufacturing the same, and more particularly, to shrinkage of a via-hole conductor and a ceramic layer in a multilayer ceramic substrate during firing. The present invention relates to an improvement for suppressing occurrence of a structural defect such as a crack due to a difference in behavior.

[0002]

2. Description of the Related Art A multilayer ceramic substrate is used for wiring these electronic components while mounting various electronic components thereon and incorporating passive elements therein. Are used in package parts for housing semiconductor elements such as ICs and LSIs, and in hybrid integrated circuit devices on which a plurality of types of electronic parts are mounted. As a material for a ceramic layer provided in a multilayer ceramic substrate, alumina ceramics are often used because of their excellent properties such as electrical insulation and chemical stability.

However, as the frequency and density of the multilayer ceramic substrate increase, the dielectric constant of the ceramic layer is required to be lower, and the above-mentioned alumina ceramic sufficiently satisfies such a requirement. The situation is getting worse. In addition, lower wiring resistance has been required for wiring conductors.

[0004] Under such circumstances, in order to achieve a lower dielectric constant, as the material of the ceramic layer, in place of the alumina _{ceramics, BaO-Al 2 O 3 -SiO} 2 mixed ceramic has attracted attention. Further, in order to realize low wiring resistance, it is preferable to use, for example, copper (Cu), gold (Au) or silver (Ag) as a material for the wiring conductor, and in particular, use copper in terms of cost. Is more preferred.

As a material for the ceramic layer, BaO-Al
_When manufacturing a multilayer ceramic substrate using a ₂ O ₃ —SiO ₂ mixed ceramic and using copper as a wiring conductor, BaO—Al ₂ O ₃ —SiO
₍₂ ) The slurry obtained by mixing the mixed ceramic raw material powder, the organic binder and the solvent is formed into a sheet by applying a sheet forming method such as a doctor blade method, and the obtained ceramic green sheet is optionally used. Then, a through-hole for a via-hole conductor is provided, and the through-hole is filled with a conductive paste containing copper, or a conductive film having a predetermined pattern is formed using a conductive paste containing copper by a screen printing method or the like. After forming by applying a film forming method, a plurality of ceramic green sheets are laminated, pressed, and a binder is removed by heating the obtained green laminate, and then firing is performed. Have been.

In the above-described method for manufacturing a multilayer ceramic substrate, the conductive paste containing copper for forming a via-hole conductor or a conductive film is made of BaO—Al ₂ O ₃ —SiO _2.
Fired simultaneously with the mixed ceramic.

However, due to the difference in shrinkage behavior in the firing step between the conductive paste containing copper and the BaO—Al ₂ O ₃ —SiO ₂ mixed ceramic, after firing, the via-hole conductor rises from other portions, or the ceramic layer becomes uneven. In some cases, a crack may occur in the portion or a crack may occur in the via-hole conductor.

In order to solve this problem, it is conceivable to add a trace amount of the same material as that contained in the ceramic layer to the conductive paste for forming the via-hole conductor, in addition to a conductive material such as copper. As described above, by adding the same material as the material contained in the ceramic layer to the conductive paste, the shrinkage behavior of the via-hole conductor during firing can be approximated to that of the ceramic layer side. The bondability with the layer can be improved.

Further, in order to prevent a crack during cooling after firing due to a difference in thermal expansion coefficient between the via hole conductor and the ceramic layer, a conductive paste for forming the via hole conductor is added to a glass having a small thermal expansion coefficient. It is also conceivable to add components.

[0010]

However, in the method of adding a trace amount of the same material as the material contained in the ceramic layer to the conductive paste for forming the via hole conductor, particularly in the case of a via hole conductor having a relatively large volume, ,
It is difficult to approximate the shrinkage behavior during firing to the shrinkage behavior on the ceramic layer side, and cracks and the like often occur during cooling after firing.

Particularly, in the ceramic layer, BaO-A
l ₂ O ₃ -SiO ₂ mixed ceramic or glass - in the case of using a material having a low thermal expansion coefficient, such as ceramics, the difference between the thermal expansion coefficient of the metal material included in the via-hole conductor becomes larger, the method Then, it is almost impossible to completely prevent cracks.

On the other hand, when a glass component having a small coefficient of thermal expansion is added to a conductive paste for forming a via-hole conductor, a material having a small coefficient of thermal expansion generally has high crystallinity and a high softening point. Due to the difference in shrinkage behavior during simultaneous firing with the ceramic constituting the ceramic layer, the bonding state between the via-hole conductor and the ceramic layer deteriorates,
Cracks and voids occur. In particular, such a phenomenon is likely to occur when the sintering start temperature of the ceramic constituting the ceramic layer is high.

It is an object of the present invention to provide a composition for a via-hole conductor, a multilayer ceramic substrate, and a method for manufacturing the same, which can solve the above-mentioned problems.

[0014]

SUMMARY OF THE INVENTION The present invention is first directed to a composition for a via-hole conductor.

The composition for a via-hole conductor according to the present invention comprises Cu, CuO, Cu ₂ O, a Cu—CuO mixture, C
u-Cu ₂ O mixture, and as a main component at least one selected from CuO-Cu ₂ O mixtures, in order to solve the technical problems described above, an average particle diameter of 0.1 to 3
It is characterized in that an inorganic pore-forming agent of 0.0 μm is added in an amount of 0.5 to 30.0% by weight based on the total of the main component and the inorganic pore-forming agent.

As the above-mentioned inorganic pore-forming agent, at least one of tungsten and an inorganic boron compound is preferably used.

The present invention is also directed to a multilayer ceramic substrate.

The multilayer ceramic substrate according to the present invention has a plurality of laminated ceramic layers having a via-hole conductor and including a low-temperature fired ceramic material sinterable at a temperature of 1050 ° C. or less, and a via-hole conductor is provided in the via-hole conductor. Is characterized in that a plurality of holes are formed, the porosity of the entire via-hole conductor is 0.3 to 40.0% by volume, the maximum hole diameter of the holes is 0.1 to 30.0 μm, And the porosity of the via-hole conductor is 0.5 to 1 in the range of 15% of the radius of the via-hole conductor measured in the radial direction from the interface between the via-hole conductor and the ceramic layer.
It is characterized by being 0.0% by volume.

In the multilayer ceramic substrate according to the present invention, the low-temperature fired ceramic material contained in the ceramic layer preferably contains a BaO—Al ₂ O ₃ —SiO ₂ mixed ceramic.

The present invention is further directed to a method for manufacturing a multilayer ceramic substrate.

According to a first aspect of the method for manufacturing a multilayer ceramic substrate according to the present invention, there is provided a method for manufacturing a substrate comprising Cu, CuO, Cu ₂ O, C
u-CuO mixtures, Cu-Cu ₂ O mixture, and Cu
At least one O-Cu selected from ₂ O mixture as a main component, tungsten having an average particle size of 0.1～30.0Myuemu, the total of the main component and the tungsten 0.5
A step of preparing a composition for a via-hole conductor to which a ceramic green layer containing BaO—Al ₂ O ₃ —SiO _{2 has been} added, and a plurality of laminated ceramic green layers including a low-temperature fired ceramic material including a BaO—Al ₂ O ₃ —SiO ₂ mixed ceramic; A through hole was formed in a specific one of the ceramic green layers, and the through hole was filled with the composition for via-hole conductors described above.The step of producing a green laminate, and the raw laminate contained water vapor. Firing in a nitrogen atmosphere at a temperature in the range of 300 to 599 ° C .;
Baking at a temperature in the range of 050 ° C.

In a second aspect of the method for manufacturing a multilayer ceramic substrate according to the present invention, the method comprises the steps of: adding Cu, CuO, Cu ₂ O,
u-CuO mixtures, Cu-Cu ₂ O mixture, and Cu
An inorganic boron compound having at least one selected from an O—Cu ₂ O mixture as a main component and having an average particle size of 0.1 to 30.0 μm is added in an amount of 0.5 to the total of the main component and the inorganic boron compound. Preparing a composition for a via-hole conductor, to which BaO—Al ₂ O ₃ —SiO ₂ is added;
Comprising a plurality of laminated ceramic green layers, including a low-temperature fired ceramic material including ₂ mixed ceramics, a through hole is formed in a specific one of the ceramic green layers,
The step of producing a raw laminate, in which the through-hole is filled with the composition for via-hole conductor, and the step of preparing the raw laminate in a nitrogen atmosphere at a temperature at which the composition for via-hole conductor and the low-temperature fired ceramic material are sintered. Baking step.

[0023]

FIG. 1 is a sectional view schematically showing a multilayer ceramic substrate 1 according to an embodiment of the present invention.

The multilayer ceramic substrate 1 has a plurality of stacked ceramic layers 2. As a wiring conductor provided in connection with such a multilayer ceramic substrate 1, several conductor films 3 are formed along a main surface of a specific ceramic layer 2. Several via-hole conductors 4 are provided therethrough.

In the multilayer ceramic substrate 1, the ceramic layer 2 is made of, for example, BaO--Al ₂ O ₃ --SiO ₂
Like the low-temperature fired ceramic material including the mixed ceramic, it is made to have a composition including the low-temperature fired ceramic material that can be sintered at a temperature of 1050 ° C. or less.

FIG. 2 is an enlarged sectional view showing a via-hole conductor 4 provided so as to penetrate the specific ceramic layer 2 shown in FIG.

Referring to FIG. 2, a plurality of holes 5 are formed in via-hole conductor 4. This porosity is 0.3 to 40.0% by volume in the entire via-hole conductor 4.
The maximum pore diameter of the pores 5 is 0.1 to 30.
0 μm. Further, the outer peripheral portion 6 of the via hole conductor 4
Where the radius of the via-hole conductor 4 measured in the radial direction from the interface between the via-hole conductor 4 and the ceramic layer 2 is 15
%, The porosity of the via-hole conductor 4 is 0.1%.
It is adjusted to be 5 to 10.0% by volume. That is, more holes 5 exist near the center of via-hole conductor 4.

In order to manufacture such a multilayer ceramic substrate 1, the following steps are performed.

First, a via-hole conductor composition for forming the via-hole conductor 4 is prepared. Via-hole conductor _{compositions, Cu, CuO, Cu 2 O} , Cu-CuO mixture, Cu-Cu ₂ O mixture, and CuO-Cu ₂ O
An inorganic pore-forming agent such as tungsten or an inorganic boron compound having at least one selected from a mixture as a main component and an average particle size of 0.1 to 30.0 μm; 0.5 to 30.0% by weight based on the total
It has been added. As for the above-mentioned main component, powder having an average particle size of 2.0 to 4.0 μm is preferably used.

The composition for via-hole conductors described above is usually used in the form of a paste. In order to form the paste, a predetermined amount of an organic vehicle is added to the above-described main component powder and inorganic pore-forming agent powder, and the mixture is stirred and kneaded by a stirring grinder or a three-roll mill. At this time, it is preferable that the powder of the main component has no coarse powder or extremely agglomerated powder, and the particle size of the largest coarse particle after the paste is formed is 50 μm or less.

The organic vehicle is a mixture of a binder and a solvent. Examples of the binder include ethyl cellulose, acrylic resin, polyvinyl butyral, and the like.
A methacrylic resin or the like can be used. As the solvent, for example, terpineol, butyl carbitol, butyl carbitol acetate, alcohols, or the like can be used. If necessary, a dispersant, a plasticizer, an activator, and the like may be added to the via-hole conductor composition paste. Further, the viscosity of the paste is preferably selected from 100 to 1000 Pa · s ⁻¹ in consideration of printability.

Further, a conductive paste for forming the conductive film 3 is prepared. As this conductive paste, for example, a paste mainly containing copper powder having an average particle size of 2.0 to 4.0 μm is used. In this conductive paste, in addition to copper, aluminum,
Nickel, silver, gold or palladium, or an alloy containing at least one of these may be used. Also,
For the purpose of controlling the shrinkage behavior during firing and improving printability and bonding strength, a resin, glass or other inorganic substance may be added, or the conductive component may be surface-treated with such a resin.

In order to form the ceramic layer 2, B
The slurry containing the low-temperature fired ceramic material including aO-Al ₂ O ₃ -SiO ₂ mixed ceramic is prepared. For example, a mixture of barium oxide, silicon oxide, alumina, calcium oxide and boron oxide powder, polyvinyl butyral as a binder, di-n-butyl phthalate as a plasticizer, and toluene and isopropylene as solvents A slurry is prepared by adding an alcohol and mixing them.

In such a slurry, an appropriate inorganic compound or glass may be added for the purpose of accelerating sintering, controlling shrinkage behavior, improving strength, and controlling electric characteristics.
Metals may be added within a range that does not impair the electrical insulation of the obtained ceramic layer 2. As the above-mentioned binder, plasticizer and solvent, those other than those exemplified above may be used. If necessary, an antistatic agent or a tackifier may be added.

The above-mentioned slurry is formed into a sheet on a suitable carrier film by applying, for example, a doctor blade method, and dried to form a sheet.
A ceramic green sheet to be the ceramic layer 2 is produced.

Next, a through-hole for providing a via-hole conductor 4 in a specific one of the plurality of ceramic green sheets obtained in this manner by, for example, drilling, punching, laser processing, or the like. Is formed. These through holes are filled with the via-hole conductor composition paste described above by applying a method such as printing.

On the main surface of a specific one of the plurality of ceramic green sheets, the above-mentioned conductive paste is provided.
For example, the conductive paste film is applied by a screen printing method, thereby forming a conductive paste film to be the conductive film 3.

Next, a plurality of ceramic green sheets are laminated, for example, at a temperature of 80 ° C. and a pressure of 200 kg.
By pressing under the condition of / cm ² , a green laminate is obtained. The green laminate comprises a plurality of laminated ceramic green layers provided by ceramic green sheets, through holes are formed in specific ones of the ceramic green layers, and the through holes are filled with a composition for via-hole conductors. ing.

In producing a green laminate having the above-described structure, the via hole conductor composition is filled in advance in the through-holes, and a conductive paste and a film to be the conductor film 3 are formed in advance. Instead of laminating a plurality of ceramic green sheets, while laminating a plurality of ceramic green sheets, the filling of the via-hole conductor composition into the through-hole and the formation of the conductive paste film may be performed, or In order to form a plurality of stacked ceramic green layers, the above-mentioned slurry is repeatedly applied by printing or the like, and during this repeated application, the through-hole is filled with the via-hole conductor composition and the conductive paste film is formed. May be formed.

Next, the green laminate is fired, whereby a multilayer ceramic substrate 1 is obtained. The details of the firing step will be described separately for the case where the inorganic pore forming agent contained in the via-hole conductor composition is tungsten and the case where the inorganic boron compound is an inorganic boron compound.

When the inorganic pore-forming agent is tungsten, the green laminate is heated in a nitrogen atmosphere containing water vapor to a temperature in the range of 300 to 599 ° C., for example, 450 ° C.
At a temperature of 2 hours with a holding time of 2 hours. At this time, the organic binder contained in each of the ceramic green layer, the via-hole conductor composition paste, and the conductive paste film is scattered, and the reaction represented by W + 3 / 2O ₂ → WO ₃ is caused in the via-hole conductor composition. Occurs.

WO ₃ produced by this reaction is in the form of a powder. The WO ₃ in the form of a powder scatters from the composition for via-hole conductors and forms holes 5 after the scatter. This hole 5
Reduces stress caused by a difference in expansion between the via-hole conductor composition and the ceramic green layer. Further, even if a trace amount of WO ₃ remains inside the via-hole conductor composition,
Since O ₃ is in a powder form, it acts sufficiently to relieve stress, and does not increase the resistance value of the via-hole conductor 4 after firing.

Next, after the above-mentioned firing, dry nitrogen atmosphere
In the temperature in the range of 600 to 1050 ° C.,
At a temperature of 980 ° C. for 1 hour.
Is done. By this firing step, the composition for via-hole conductor
In the material, CuO → Cu + 1 / 2O_Two Cu_TwoO → 2Cu + 1 / 2O_Two A reaction such as the following occurs, and the volume of the via-hole conductor composition decreases.
Decrease. At this time, the via-hole conductor composition and the ceramic
BaO-Al contained in the black green layer_TwoO _Three-S
iO_TwoThe difference in shrinkage onset temperature between
Although the stress is generated due to the difference in the amount of
Works to alleviate stress.
A bulge occurs in the part of the body 4 and cracks in the ceramic layer 2
Or cracks in the beehole conductor 4
Is suppressed.

On the other hand, as an inorganic pore-forming agent contained in the via-hole conductor composition, an inorganic boron compound such as H
_{When 3} BO ₃ is used, the raw laminate is placed in a nitrogen atmosphere in a composition for a via-hole conductor and BaO.
It is fired at a temperature at which a low-temperature fired ceramic material containing -Al ₂ O ₃ -SiO ₂ mixed ceramic is sintered, for example, at a temperature of 980 ° C., with a holding time of 1 hour. The nitrogen atmosphere at the time of firing may be a nitrogen atmosphere containing water vapor or a dry nitrogen atmosphere.

In this firing step, H ₃ BO ₃ is decomposed and scattered, so that holes 5 are formed after the scatter.
Since the holes 5 act to relieve stress as in the case of using the above-described tungsten, after firing, a bulge occurs in the portion of the via-hole conductor 4, a crack occurs in the ceramic layer 2, or the via-hole conductor 4 The occurrence of cracks can be suppressed.

As the inorganic pore-forming agent, both tungsten and an inorganic boron compound may be used in combination.

As described above, the average particle diameter of the tungsten or inorganic boron compound contained in the via-hole conductor composition is 0.1 to 30.0 μm, and 0.5 to 30.
It is added in an amount of 0% by weight.

If the average particle size of the inorganic pore-forming agent is less than 0.1 μm or the addition amount is less than 0.5% by weight, sufficient pores 5 in the via-hole conductor 4 after firing are formed. Since it is not formed, the stress due to the difference in thermal expansion between the ceramic layer 2 and the via-hole conductor 4 cannot be sufficiently reduced, and therefore, the separation easily occurs at the interface between the ceramic layer 2 and the via-hole conductor 4.

On the other hand, when the average particle size of the inorganic pore-forming agent is 30.
When the inorganic pore-forming agent is tungsten when the thickness is larger than 0 μm or when the added amount exceeds 30% by weight, when the tungsten is oxidized at the time of firing and changes to WO ₃ , When the agent is an inorganic boron compound, when the inorganic boron compound is decomposed at the time of firing, the volume expansion of the via-hole conductor 4 becomes too large, so that cracks are formed in the ceramic layer 2 around the via-hole conductor 4. Is more likely to occur.

In the multilayer ceramic substrate 1 obtained, the maximum diameter of the holes 5 in the via-hole conductors 4 is set to 0.1 to 30.0 μm as described above.

When the maximum hole diameter is smaller than 0.1 μm, the stress is not sufficiently relaxed due to the difference in shrinkage between the via hole conductor 4 and the ceramic layer 2, and the via hole conductor 4 and the ceramic layer 2 Separation easily occurs at the interface with the substrate. On the other hand, if the maximum pore diameter is larger than 30.0 μm, sufficient adhesion strength between the side wall of the via-hole conductor 4 and the ceramic layer 2 cannot be obtained, resulting in poor thermal reliability.

As described above, the via-hole conductor 4
The total porosity is set to be 0.3 to 40.0% by volume.

Even if the maximum pore diameter is set to be 0.1 to 30.0 μm, the porosity of the via-hole conductor 4 is 0.3
When the volume percentage is lower than the volume percentage, the relaxation of the stress due to the difference in the amount of shrinkage between the via-hole conductor 4 and the ceramic layer 2 becomes insufficient, and peeling is likely to occur at the interface between the via-hole conductor 4 and the ceramic layer 2.

On the other hand, if the porosity exceeds 40.0% by volume, sufficient adhesion strength between the side wall of the via hole conductor 4 and the ceramic layer 2 cannot be obtained, resulting in poor thermal reliability. .

As described above, the via-hole conductor 4
Of the via-hole conductor 4 measured in the radial direction from the interface between the via-hole conductor 4 and the ceramic layer 2.
Is set so that the porosity of the via-hole conductor 4 is 0.5 to 10.0% by volume in the range of 15% of the radius of

Outside of such a range, sufficient adhesion strength between the side wall of the via-hole conductor 4 and the ceramic layer 2 cannot be obtained. In order to obtain a higher adhesion strength, it is more preferable that the porosity of the via-hole conductor 4 is 0.5 to 1.0% by volume within a range of 5% of the radius of the via-hole conductor 4.

Next, a description will be given of an experimental example carried out to evaluate the composition for a via-hole conductor according to the present invention.

[0058]

[Experimental example] A mixture of barium oxide, silicon oxide, alumina, calcium oxide and boron oxide, polyvinyl butyral as a binder, di-n-butyl phthalate as a plasticizer, and toluene and isopropylene alcohol as solvents And a slurry is prepared by mixing them. The slurry is formed into a sheet on a carrier film by a doctor blade method, and then dried to a thickness of 125 μm.
m of ceramic green sheets.

Next, a carbon dioxide laser was applied to the ceramic green sheets to form through holes having a diameter of 200 μm.

On the other hand, Cu powder having an average particle size of 3 μm, CuO
As shown in Table 1, W powder having various average particle diameters was added so as to have various contents with respect to the main component obtained by mixing powder and Cu ₂ O powder in appropriate amounts. As shown, H ₃ BO ₃ powders having various average particle sizes are added so as to have various contents, and further, an acrylic resin as a binder and terpineol as a solvent are added, and these are kneaded. Then, a composition paste for via-hole conductor was prepared. The amount of the binder in this paste was 10% by weight based on the main component.

Next, the above-mentioned via-hole conductor composition paste was filled in the through-holes provided in the above-mentioned ceramic green sheet by applying a printing method via a carrier film.

Next, seven ceramic green sheets to which the via-hole conductor composition paste was applied as described above were laminated, and the temperature was 80 ° C. and the pressure was 200 kg / cm ^2.
By pressing under the conditions described above, a raw laminate was obtained.

Next, in order to decompose and remove organic components such as a binder contained in the green laminate, the green laminate is fired at 450 ° C. for 2 hours in a nitrogen atmosphere containing steam, and then fired in a furnace. The internal atmosphere was switched to a dry nitrogen atmosphere and 9
The temperature was raised to a temperature of 80 ° C., and the firing step was continued while maintaining the temperature for 1 hour. As a result, a multilayer ceramic substrate as a sample in which the via-hole conductor and the ceramic layer were simultaneously fired was obtained.

With respect to the obtained multilayer ceramic substrate of each sample, the appearance of the via-hole conductor was visually inspected.
The presence or absence of cracks or cracks in the ceramic layer and via-hole conductor was evaluated.

In the multilayer ceramic substrate of each sample, the maximum hole diameter was measured by observing the cross section of the via-hole conductor using a scanning microscope, and the hole diameter of the hole hole was 0.1 μm or more per unit area. The porosity was calculated by determining the number of holes and the diameter of each hole. As for the porosity, the porosity in the range of 15% of the radius of the via hole conductor, which is the outer peripheral portion of the via hole conductor, was also determined.

The above evaluation results are shown in Tables 1 and 2.

[0067]

[Table 1]

[0068]

[Table 2]

In Tables 1 and 2, the samples numbered with “*” are out of the scope of the present invention, and all of them have cracks or cracks.

More specifically, in Sample 1, the W content was
0.3% by weight of less than 0.5% by weight, and the total porosity of the via-hole conductor is 0.1% by weight of less than 0.3% by weight.
% By volume, and the porosity in the range of 15% is 0.5%.
It is less than 0.3% by volume.

In sample 6, the total porosity of the via-hole conductor was 48.0% by volume exceeding 40.0% by volume, and the porosity in the range of 15% was 10.0% by volume.
15.5% by volume.

In sample 7, the maximum hole diameter in the via-hole conductor was 0.05 μm, which was less than 0.1 μm, and
% Porosity in the range of less than 0.5 vol.
% By volume.

In sample 14, the average particle size of the W powder was 3
35.0 μm exceeding 0.0 μm, and the maximum pore diameter in the via-hole conductor exceeds 30.0 μm.
0 μm, and the porosity in the range of 15% is 10.
It is 12.5% by volume exceeding 0% by volume.

In Sample 15, the content of H ₃ BO ₃ was
0.3% by weight of less than 0.5% by weight, and the total porosity of the via-hole conductor is 0.1% by weight of less than 0.3% by volume.
% By volume, and the porosity in the range of 15% is 0.5%.
It is less than 0.3% by volume.

In sample 20, the total porosity of the via-hole conductor was more than 40.0% by volume and 50.5% by volume.
The porosity in the range of 15% is 16.0% by volume exceeding 10.0% by volume.

In sample 21, the maximum hole diameter in the via-hole conductor was 0.05 μm, which was less than 0.1 μm, and
The porosity in the range of 5% is less than 0.5% by volume.
It is 1% by volume.

In sample 28, the average particle diameter of the H ₃ BO ₃ powder was 35.0 μm exceeding 30.0 μm, the maximum pore diameter in the via hole conductor was 38.0 μm exceeding 30.0 μm, and 15% Porosity in the range of
It is 12.5% by volume, which exceeds 10.0% by volume.

On the other hand, Samples 2 to 5, 8 to 13, 16 to 19, and 22 to 2 within the scope of the present invention
According to No. 7, no crack or crack occurred.

[0079]

As described above, according to the composition for via-hole conductor according to the present invention, Cu, CuO, Cu ₂ O, C
u-CuO mixtures, Cu-Cu ₂ O mixture, and Cu
At least one member selected from O-Cu ₂ O mixture as a main component, the average particle size 0.1~30.0μm example an inorganic pore-forming agent comprising at least one of tungsten and inorganic boron compounds, and the main component Since 0.5 to 30.0% by weight based on the total amount of the inorganic pore-forming agent is added, if this is used to produce a multilayer ceramic substrate provided with via-hole conductors, the firing step will result in an inorganic The hole-forming agent is scattered, and holes are formed in the via-hole conductor,
Due to the holes, the stress due to the difference in the amount of shrinkage between the via-hole conductor and the ceramic layer is reduced, and therefore,
After the firing, it is possible to suppress the occurrence of a bump in the via-hole conductor, the occurrence of cracks and cracks in the ceramic layer, and the occurrence of cracks in the via-hole conductor.

According to the multilayer ceramic substrate of the present invention, a plurality of holes are formed in the via-hole conductor, and the porosity of the entire via-hole conductor is 0.3 to 40.0% by volume.
Wherein the maximum pore diameter of the pores is 0.1 to 30.0 μm, which is 15% of the radius of the via-hole conductor measured in the radial direction from the interface between the via-hole conductor and the ceramic layer at the outer peripheral portion of the via-hole conductor In the range, the porosity of the via-hole conductor is 0.5 to 10.0% by volume, so that the protrusion in the via-hole conductor, cracks or cracks in the ceramic layer, and cracks in the via-hole conductor are less likely to occur.
Further, the adhesion strength between the via-hole conductor and the ceramic layer can be increased, and the thermal reliability of the multilayer ceramic substrate can be increased.

According to the method for manufacturing a multilayer ceramic substrate according to the present invention, since the via-hole conductor composition as described above is used, a multilayer ceramic having a ceramic layer containing a BaO—Al ₂ O ₃ —SiO ₂ mixed ceramic is used. The substrate can be manufactured in good condition. Therefore,
A multilayer ceramic substrate having a low dielectric constant in a ceramic layer and a low wiring resistance in a wiring conductor can be manufactured in a favorable state, and can advantageously cope with higher frequency and higher density of the multilayer ceramic substrate. .

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a multilayer ceramic substrate 1 according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view schematically showing a via-hole conductor 4 provided so as to penetrate a specific ceramic layer 2 shown in FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 multilayer ceramic substrate 2 ceramic layer 4 via-hole conductor 5 void 6 outer periphery

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // H01B 1/20 H01B 1/20 A F term (Reference) 4E351 AA07 BB01 BB26 BB31 BB44 BB49 CC12 CC23 CC31 CC33 DD04 DD17 DD28 DD33 GG03 5E346 AA15 AA41 CC19 CC32 DD13 EE21 GG04 GG09 HH06 HH11 HH25 5G301 DA06 DA14 DA23 DA32 DD01

Claims (6)

[Claims] 1. Cu, CuO, Cu_TwoO, Cu-CuO
Mixture, Cu-Cu _TwoO mixture, and CuO-Cu_Two
O as a main component, at least one selected from O mixtures.
An inorganic pore-forming agent having an average particle size of 0.1 to 30.0 μm is
0.5 to the total of the main component and the inorganic pore-forming agent
A composition for a via-hole conductor added at 30.0% by weight. 2. The composition for a via-hole conductor according to claim 1, wherein the inorganic pore-forming agent is at least one of tungsten and an inorganic boron compound. 3. It has a via-hole conductor and 1050 ° C.
A plurality of laminated ceramic layers including a low-temperature fired ceramic material sinterable at the following temperature, wherein a plurality of holes are formed in the via-hole conductor, and the porosity of the entire via-hole conductor is 0; 0.3 to 40.0% by volume,
The maximum pore diameter of the pores is 0.1 to 30.0 μm,
The porosity of the via-hole conductor is in the range of 0.5% to 15% of the radius of the via-hole conductor measured in the radial direction from the interface between the via-hole conductor and the ceramic layer in the outer peripheral portion of the via-hole conductor. A multilayer ceramic substrate having a volume ratio of 10.0%. 4. The low-temperature fired ceramic material is BaO
-Al including ₂ O ₃ -SiO ₂ mixed ceramic, multilayer ceramic substrate according to claim 3. 5. Cu, CuO, Cu_TwoO, Cu-CuO
Mixture, Cu-Cu _TwoO mixture, and CuO-Cu_Two
O as a main component, at least one selected from O mixtures.
Tungsten having an average particle size of 0.1 to 30.0 μm is
0.5 to 3 with respect to the sum of the components and the tungsten
Preparation of via-hole conductor composition with 0.0% by weight added
And BaO-Al_TwoO_Three-SiO_TwoMixed ceramic containing low
Multiple stacked ceramics containing warm fired ceramic material
A ceramic green layer.
A through-hole is formed in a fixed object, and the via hole is formed in the through-hole.
To produce a green laminate filled with a conductor composition
And placing the green laminate in a nitrogen atmosphere containing water vapor.
And firing at a temperature in the range of 300-599 ° C.,
In a dry nitrogen atmosphere, in the range of 600 to 1050 ° C
Firing at a temperature of
Manufacturing method. 6. Cu, CuO, Cu_TwoO, Cu-CuO
Mixture, Cu-Cu _TwoO mixture, and CuO-Cu_Two
O as a main component, at least one selected from O mixtures.
An inorganic boron compound having an average particle size of 0.1 to 30.0 μm
The amount of 0.1 to the total of the main component and the inorganic boron compound.
Composition for via-hole conductor added with 5 to 30.0% by weight
And a step of preparing BaO-Al_TwoO_Three-SiO_TwoMixed ceramic containing low
Multiple stacked ceramics containing warm fired ceramic material
A ceramic green layer.
A through-hole is formed in a fixed object, and the via hole is formed in the through-hole.
To produce a green laminate filled with a conductor composition
The raw laminate is placed in a nitrogen atmosphere,
The conductor composition and the low-temperature fired ceramic material
Baking at a sintering temperature.
Manufacturing method of the substrate.