JP3538549B2 - Wiring board and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring substrate having an insulating substrate made of ceramics mainly composed of aluminum oxide, and more particularly, to a surface wiring layer made of a low-resistance conductor and formed by co-firing with the insulating substrate. The present invention relates to a wiring board provided with a metal fitting such as a connection terminal and a heat sink and capable of being brazed, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, heat generated by a semiconductor device has been increasing along with high integration of semiconductor elements. In order to eliminate malfunction of the semiconductor device, a wiring board capable of releasing such heat to the outside of the device is required. On the other hand, as for the electrical characteristics, a delay in signal has become a problem due to an increase in operation speed, and it has been required to use a conductor having a small conductor loss, that is, a low-resistance conductor.

[0003] As a wiring board on which such a semiconductor element is mounted, from the viewpoint of reliability, an alumina ceramic is used as an insulating substrate, and a wiring layer made of a refractory metal such as tungsten or molybdenum is deposited on the surface or inside thereof. The formed ceramic wiring board is frequently used. However, in a wiring layer made of a high melting point metal that has been widely used, the resistance can be reduced only to about 10 mΩ / □ at most.

On the other hand, in recent years, a multilayer wiring board using so-called glass ceramics which can be co-fired with copper or silver which is a low-resistance conductor has been proposed. However, the thermal conductivity of glass ceramics is at most several W / m · K.
However, it has become difficult to solve the thermal problem.

In order to solve the thermal problem and the electrical problem at the same time, as a method for simultaneously solving the above problems, a wiring layer made of copper or a combination of copper and tungsten or molybdenum is simultaneously fired on an insulating substrate made of aluminum oxide ceramics. Have been proposed in Japanese Patent Application Laid-Open Nos. 8-8502, 7-15101, and 2666744.

[0006]

However, in contrast to a conventional insulating substrate made of aluminum oxide (alumina) ceramic, a wiring board having a wiring layer containing copper as a conductor component is different from a conventional insulating substrate made of aluminum oxide (alumina) ceramic. Due to the large difference in thermal expansion, the adhesion of the copper-containing wiring layer to the insulating substrate was small.

Therefore, for example, when various electronic components are mounted on the surface wiring layer formed on the surface of the insulating substrate, the surface wiring layer peels off from the insulating substrate, and the mounting reliability of the electronic component is impaired. In particular, there has been a problem that the metal fittings such as connection terminals are easily detached even if they are brazed to the surface wiring layer.

Accordingly, the present invention provides a low-resistance surface wiring formed by simultaneous sintering with an insulating substrate made of aluminum oxide ceramic, containing copper, and capable of imparting excellent adhesive strength even when brazing metal fittings or the like. It is an object of the present invention to provide a wiring board having a layer and a method for manufacturing the same.

[0009]

Means for Solving the Problems As a result of repeated studies on the above problems, the present inventors have found that copper, tungsten and / or copper as a component for forming a surface wiring layer in a wiring substrate using alumina ceramics as an insulating substrate. In addition to molybdenum, from the group of Ti, Cr, Mn, Fe, Co and Ni
By including at least one selected amount in an appropriate amount, the adhesion strength of the surface wiring layer to the insulating substrate can be increased, and as a result, wiring having excellent reliability not only in brazing metal fittings but also in mounting various electronic components. We found that we could provide a substrate.

That is, the wiring board of the present invention is formed by simultaneously firing an insulating substrate made of ceramics containing aluminum oxide as a main component and having a relative density of 95% or more and at least the surface of the insulating substrate. With respect to 100 parts by volume of the main conductor component composed of 10 to 70% by volume of copper (Cu) and 30 to 90% by volume of tungsten (W) and / or molybdenum (Mo), Ti, Cr, Mn, Fe, C
a surface containing at least one selected from the group consisting of o and Ni in a ratio of 0.01 to 5 parts by volume in terms of metal, and having at least tungsten and / or molybdenum particles dispersed and contained in a matrix made of copper; It is characterized by comprising a wiring layer.

Further, according to the method of manufacturing a wiring board of the present invention, copper (Cu) -containing powder is coated on the surface of a green sheet containing a ceramic component containing aluminum oxide as a main component in an amount of 10 to 70% by volume in terms of metal. , Tungsten (W) and / or molybdenum (Mo) containing powder in metal conversion
For 100 parts by volume of the main conductor component consisting of 0 to 90% by volume, from the group of Ti, Cr, Mn, Fe, Co and Ni
The selected at least one kind of contained powder is 0.0
After printing and applying a conductor paste containing 1 to 5 parts by volume in a circuit pattern, the green sheets are laminated and fired in a non-oxidizing atmosphere at 1200 to 1500 ° C. to obtain a relative density of 95%. A surface wiring layer is formed on the surface of the insulating substrate made of the above aluminum oxide ceramic.

The above-mentioned wiring board and its manufacturing method
When the sheet resistance of the surface wiring layer is 8 mΩ / □ or less,
A metal fitting is brazed to the surface wiring layer, and a manganese compound is added to the aluminum oxide ceramic in an amount of 2.0 to 6.0 in terms of MnO _2.
It is desirable to contain it in a proportion of weight%.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view showing an embodiment of a wiring board according to the present invention. The wiring board of FIG. 1 has a plurality of insulating layers 1a made of oxide ceramics.
A surface wiring layer 2a is provided on the surface of an insulating substrate 1 on which 1b and 1c are laminated, and an internal wiring layer 2b is provided between the insulating layers 1a, 1b and 1c.

According to the present invention, the surface wiring layer 2a and the internal wiring layer 2b are formed of a conductor mainly composed of a composite material containing at least copper and tungsten (W) and / or molybdenum (Mo). The internal wiring layer 2b and the surface wiring layer 2a are formed by simultaneous firing with the insulating substrate 1.

The wiring layers of each layer are electrically connected by a via-hole conductor 3 formed so as to penetrate the insulating layer. It is desirable that the via hole conductor 3 is also formed by simultaneous firing using the same conductive material as the surface wiring layer 2a and the internal wiring layer 2b.

(Insulating Substrate) In the present invention, the insulating substrate 1
Is mainly composed of aluminum oxide, but has a relative density of 95% or more, particularly 97%, and more preferably 98% in order to increase the thermal conductivity and strength of the insulating substrate and further enhance the adhesion of the surface wiring layer. It is desirable to be composed of the above high-density body, and the thermal conductivity is 10 W / m · K or more, especially 15 W
/ M · K or more, more preferably 17 W / m · K or more.

According to the present invention, in order to achieve shape retention by simultaneous sintering with the surface wiring layer 2a and the internal wiring layer 2b, 12
Although it is necessary to fire at a low temperature of 00 to 1500 ° C., according to the present invention, it is necessary to densify to a relative density of 95% or more even in firing at such a low temperature.

From this viewpoint, the insulating substrate 1 of the present invention contains aluminum oxide as a main component, specifically, contains aluminum oxide in a proportion of 90% by weight or more. , The Mn compound is MnO
It is desirable to contain it in a ratio of 2.0 to 6.0% by weight in terms of _two . That is, if the amount of the Mn compound is less than 2.0% by weight, it is difficult to achieve densification at 1200 to 1500 ° C., and if it is more than 6.0% by weight, the insulating property of the insulating substrate 1 decreases. Optimal range of the Mn compound is 3-5 wt% at MnO ₂ basis.

Further, in the insulating substrate 1, SiO ₂ and alkaline earth element oxides such as MgO, CaO, and SrO are added as a third component in order to enhance the simultaneous sintering property with the copper-containing conductor. At a ratio of 0.4 to 8% by weight.

Further, W, Mo or the like may be contained as a fourth component in a proportion of 2% by weight or less as a coloring component.

The above-mentioned components other than aluminum oxide exist as an amorphous phase or a crystal phase at the grain boundaries of the main crystal phase of aluminum oxide. However, in order to enhance the thermal conductivity, a crystal containing an auxiliary component in the grain boundaries is required. Desirably, a phase is formed.

The aluminum oxide main crystal phase forming the insulating substrate 1 exists as granular or columnar crystals, and the average crystal grain size of these main crystal phases is 1.5 to 5.0.
μm is desirable. When the main crystal phase is composed of columnar crystals, the average crystal grain size is based on the minor axis diameter. If the average crystal grain size of the main crystal phase is smaller than 1.5 μm, it is difficult to achieve high thermal conductivity, and the average grain size is 5.0 μm.
If it is larger than m, it is difficult to obtain sufficient strength required as a substrate material.

(Wiring Layer) On the other hand, the surface wiring layer 2a and the internal wiring layer 2b are made of T , in addition to copper, W and / or Mo.
selected from the group consisting of i, Cr, Mn, Fe, Co and Ni
Containing at least one as an essential component,
In addition to increasing the adhesion of at least the surface wiring layer 2a to the insulating substrate 1, reducing the resistance of the wiring layer and achieving simultaneous sinterability with the insulating substrate 1, the shape retention after the simultaneous firing of the surface wiring layer It is necessary to maintain sex.

The specific composition ratio is such that copper is 10 to 70% by volume, particularly 40 to 60% by volume, and W and / or Mo is 30% by volume.
Ti, Cr, Mn, Fe, C with respect to 100 parts by volume of the main conductor component consisting of 90 to 90% by volume, particularly 40 to 60% by volume.
It is necessary to contain at least one selected from the group consisting of o and Ni at a ratio of 0.01 to 5 parts by volume, particularly 0.1 to 3 parts by volume in terms of metal.

The reason why the ratio of each component is limited to the above is that copper is less than 10% by volume and W and M
When the amount of o is more than 90% by volume, the resistance of the wiring layer is 8 mΩ.
If it is higher than / □, the content of copper is more than 70% by volume, and the content of W or Mo is less than 30% by volume, the shape retention after the simultaneous firing of the surface wiring layer is reduced, and the surface wiring layer 2a is blurred. This is because, for example, the surface wiring layer is aggregated by the molten copper, and the wiring is disconnected due to the thermal expansion coefficient difference between the insulating substrate and the wiring layer.
Also, the group of Ti, Cr, Mn, Fe, Co and Ni
If at least one selected from the group is less than 0.01 part by volume, the adhesion strength of the surface wiring layer to the insulating substrate is not sufficient, and if it is more than 5 parts by volume, the resistance of the wiring layer increases,
This is because a sheet resistance of 8 mΩ / □ or less cannot be achieved.

In the present invention, it is desirable that the W and / or Mo are dispersed and contained in a matrix made of copper as spherical or sintered particles of several particles having an average particle diameter of 1 to 10 μm. . When the average particle size is smaller than 1.0 μm, the shape retention of the surface wiring layer 2a is deteriorated, the structure becomes porous and the resistance of the wiring layer increases, and when the average particle size exceeds 10 μm, the copper matrix becomes W This is because the resistance of the wiring layer is increased by being separated by the particles of Mo or Mo, and the copper component is separated to easily cause bleeding. Most preferably, W and / or Mo are dispersed with a mean particle size of 1.3 to 5 μm, particularly 1.3 to 3 μm.

The transition metals other than W and Mo include:
Specifically, Ti, Cr, Mn, Fe, Co and Ni
And at least one selected from the group consisting of Ti, Cr 2 , Co and Ni is particularly desirable. This transition metal is
In the wiring layer, it exists as a metal or a metal compound such as an oxide or a nitride, and exists as dispersed particles like W or Mo in a matrix made of copper, but has an average particle diameter of 10 μm or less, particularly 3 μm or less. Is desirably present as particles. When the average particle size is larger than 10 μm, the resistance of the wiring layer is increased by dividing the copper matrix together with the W and / or Mo particles, or the copper component is separated to easily cause bleeding. It is.

In order to improve the adhesion to the insulating substrate 1, aluminum oxide or an insulating substrate is added to the main conductor component 100 volume parts in the surface wiring layer 2 a and the internal wiring layer 2 b. It is also possible to contain ceramics of the same component in a ratio of 0.05 to 2 parts by volume, particularly 0.1 to 1 part by volume. If the amount of the ceramic component is more than 2 parts by volume, the resistance of the wiring layer increases extremely.

Further, in the wiring board according to the present invention, the insulating substrate 1 of the copper component in the surface wiring layer 2a and the internal wiring layer 2b is provided.
It is desirable that the diffusion distance x to the substrate be 20 μm or less, particularly 10 μm or less. This is because if the diffusion distance of copper into the ceramic exceeds 20 μm, the insulation between the wiring layers decreases, and the reliability as a wiring substrate decreases. By setting the copper diffusion distance to 20 μm or less, the minimum distance between wiring layers formed on the same plane can be reduced to 100 μm.
m, and when a plurality of via-hole conductors are formed in one insulating layer, the minimum distance between the via-hole conductors 3 is also reduced to 100 μm or less for the same reason as described above. Can be smaller.

(Mounting of metal fittings) In the present invention, as shown in FIG.
A connection terminal such as o, Cu, Cu-W or a metal fitting such as a heat sink can be attached. As a method of attaching the metal fitting, a thickness of 1.5 to 5 mm is formed on the surface of the surface wiring layer 2a.
After forming a plating layer 4 of Ni and Au having a thickness of μm, Ag-C
The metal fitting 6 is joined with a brazing material 5 such as u, Au-Sn, or Ag-Cu-Ti. When an Ag—Cu-based brazing material is used, it has a reactivity with the surface wiring layer 2a.
It is necessary to protect the surface wiring layer by increasing the plating thickness to 1 μm or more.

(Manufacturing Method) Next, a method of manufacturing a wiring board according to the present invention will be specifically described. First, in order to form an insulating substrate, an aluminum oxide raw material powder which is a main component of oxide ceramics has an average particle size of 0.5 to 2.
5 μm, especially 0.5-2.0 μm powder is used. If the average particle size is smaller than 0.5 μm, it is difficult to handle the powder, and the cost of the powder is increased.
If the temperature is higher than 1,500 ° C. or less, it is difficult to fire.

In order to improve the low-temperature sintering property of the aluminum oxide powder, MnO ₂ is added as a _second component in an amount of 2.0 to 6.0% by weight, particularly 3.0 to 3.0% by weight.
5.0% by weight, as the third component, SiO ₂ , MgO,
CaO powder or the like at a ratio of 0.4 to 8% by weight,
, A metal powder such as W or Mo or an oxide powder is added at a ratio of 2% by weight or less in terms of metal. In addition, in addition to the oxide powder, the above oxide may be added as a carbonate, nitrate, acetate, or the like capable of forming an oxide by firing.

Then, a sheet-like molded body for forming an insulating layer is prepared using the mixed powder. The sheet-shaped molded body can be produced by a well-known molding method.
For example, a slurry is prepared by adding an organic binder or a solvent to the mixed powder, and then formed by a doctor blade method, or an organic binder is added to the mixed powder, and press-formed, roll-formed, or the like to form a sheet having a predetermined thickness. Body can be made.

With respect to the sheet-like molded body thus produced, copper (Cu) -containing powder was used as a conductor component in an amount of 10 to 70% by volume, particularly 40 to 60% by volume, in terms of metal, and tungsten (W) and / or Alternatively, the content of molybdenum (Mo) -containing powder is 30 to 90% by volume, particularly 40 to 60% by volume in terms of metal.
Against main conductor component 100 parts by volume consisting of, Ti, C
r, Mn, Fe, Co and Ni
A conductor paste containing at least one kind of contained powder at a metal conversion rate of 0.01 to 5 parts by volume, particularly 0.1 to 3 parts by volume, is prepared, and this paste is screened on each sheet-like insulating layer. Printing and coating are performed by a method such as printing or gravure printing. In this conductor paste, aluminum oxide powder or the same composition powder as the oxide ceramic component forming the insulation layer was added to 100 parts by volume of the main conductor component in order to enhance the adhesion to the insulation layer. 0.05-2 volume parts,
In particular, it can be added at a ratio of 0.1 to 1 part by volume.

As the copper-containing powder to be mixed into the paste,
Examples of the Cu powder, copper oxide (CuO, Cu2O) powder, or a mixed powder thereof, and a powder containing W and / or Mo include W powder, Mo powder, a mixed powder thereof, and T powder.
selected from the group consisting of i, Cr, Mn, Fe, Co and Ni
Examples of the powder containing at least one kind include metal powders, oxide powders, nitride powders, and especially oxide powders.

In the case of forming a via-hole conductor, a via-hole having a diameter of 50 to 250 μm is formed in a sheet-like molded body by a microdrill, a laser, or the like, and then the copper-containing conductor paste is filled in the via-hole. Fill.

Thereafter, the sheet-like molded body on which the conductive paste was applied by printing was aligned and laminated and pressed, and the laminated body was fired in a non-oxidizing atmosphere at a maximum firing temperature of 1200 to 1500 ° C. The firing is performed under the following conditions.

If the firing temperature at this time is lower than 1200 ° C., the aluminum oxide insulating substrate cannot be densified to a relative density of 95% or more when ordinary raw materials are used, and the thermal conductivity and strength are reduced, and If the temperature is higher than ℃, sintering of W or Mo itself proceeds, and it is not possible to maintain a uniform structure with copper, and if it is difficult to maintain a low resistance, a sheet resistance of 8 mΩ / □ or less cannot be obtained. In addition, the grain size of the main crystal phase of the oxide ceramics increases, abnormal grain growth occurs, and the diffusion speed increases as the length of the grain boundary, which is the path when copper diffuses into the ceramics, decreases. This is because it is difficult to suppress the diffusion distance to 30 μm or less. Preferably, 1250-1400
The range of ° C is good.

As the non-oxidizing atmosphere at the time of this firing, it is preferable to use nitrogen or a mixed atmosphere of nitrogen and hydrogen. In particular, in order to suppress the diffusion of copper in the wiring layer, hydrogen and hydrogen are not used. Dew point + 10 ° C or less including nitrogen, especially-
It is desirable that the atmosphere be a non-oxidizing atmosphere of 10 ° C. or less. Note that an inert gas such as an argon gas may be mixed into this atmosphere, if desired. If the dew point during firing is higher than + 10 ° C., the oxide ceramic reacts with moisture in the atmosphere during firing to form an oxide film, and the oxide film reacts with copper of the copper-containing conductor, resulting in a low conductor. This not only hinders resistance but also promotes copper diffusion.

By controlling the sintering temperature and atmosphere to perform sintering, a surface having an average surface roughness Ra of 1 μm or less, particularly 0.7 μm or less, which is excellent in smoothness, can be formed.

Further, when a metal fitting is attached to this wiring board, a plating film of 1.5 to 5 μm of Ni, Au or the like is formed on the surface wiring layer by electrolytic plating or electroless plating. Desirably, a Ni plating film having a thickness of 1 to 3 μm and an Au plating film having a thickness of 0.5 to 2 μm are sequentially formed.
The metal fitting 6 made of Fe-Ni-Co, Cu, Cu-W or the like can be joined by a brazing material such as Cu, Au-Sn, or Ag-Cu-Ti.

[0042]

EXAMPLES Example 1 MnO ₂ was added to aluminum oxide powder (average particle size 1.8 μm) at the ratios shown in Tables 1 and ₂ , SiO ₂ was 3% by weight, and MgO was 0.1%. After adding and mixing at a ratio of 5% by weight, an acrylic binder as an organic resin for molding (binder) and toluene as a solvent were mixed to prepare a slurry, and then a 250 μm thick sheet was formed by a doctor blade method. Molded. Then, a via hole having a hole diameter of 120 μm was formed at a predetermined location.

Next, copper powder having an average particle size of 5 μm, W powder or Mo powder having an average particle size of 0.8 to 12 μm, NiO powder having an average particle size of 1 μm, and in some cases, having an average particle size of 0.1 μm. 5 μm Al ₂ O ₃ powder was mixed at the ratios shown in Tables 1 and 2, and a conductive paste was prepared using an acrylic binder and acetone as a solvent.

Then, the above-mentioned conductor paste was printed and applied on the sheet-like molded body, and the via-hole conductor of each sheet-like molded body was also filled with the above-mentioned conductor paste for wiring layer. Each sheet-like molded body produced as described above was aligned and laminated and pressed to produce a molded laminate. Thereafter, the molded body laminate is placed in an oxygen-containing atmosphere substantially free of moisture (N
₍₂ + O ₂ or in the air), and then fired at a firing temperature shown in Tables 1 and 2 in a nitrogen-hydrogen mixed atmosphere at a dew point of −10 ° C.

The relative density of the insulating substrate in the manufactured wiring substrate was measured by the Archimedes method, and the thermal conductivity (thickness: 3 mm) and the volume resistivity were measured by the laser flash method.

After measuring the conductor resistance, length, width and thickness of the wiring on the surface wiring layer of the wiring board,
The sheet resistance (mΩ / □) converted into a μm conductor was calculated. In addition, the structure was observed with a scanning electron microscope, and the particle size of W and / or Mo particles in the surface wiring layer was measured. Further, the appearance of the wiring board was inspected, and the occurrence of bleeding of the surface wiring layer and the presence or absence of peeling of the surface wiring layer were observed. The results are shown in Tables 3 and 4.

Further, after a 2 μm Ni plating layer and a 1 μm Au plating were applied to a 2 mm × 20 mm surface wiring layer, as shown in FIG.
After the character (lead) was brazed with a brazing material made of Au-Sn, the metal fitting was pulled vertically, and the strength (kgf) when the metal fitting was removed was measured.

[0048]

[Table 1]

[0049]

[Table 2]

[0050]

[Table 3]

[0051]

[Table 4]

As shown in Tables 1 to 4, Sample No. 1 in which the amount of transition metal in the surface wiring layer was less than 0.01 part by volume,
In Sample No. 3, sufficient bonding strength of the surface wiring layer was not obtained, and in Sample No. 2 in which 5 parts by volume of Al ₂ O ₃ was added, the bonding strength was improved, but the sheet resistance of the wiring layer was low. Increased. The sample No. having a transition metal content of more than 5% by volume.
In No. 13, the sheet resistance of the surface wiring layer was larger than 8 mΩ / □, and a low-resistance wiring layer could not be formed.

Further, the amount of MnO ₂ is small and the relative density is 95%.
%, The thermal conductivity of the sample No.
/ M · K, and the bonding strength of the surface wiring layer also decreased. Further, in Samples Nos. 20 and 21 in which the copper content in the surface wiring layer is less than 10% by volume, the conductor resistance is higher than 8 mΩ / □ and more than 70% by volume.
In the case of o.28, the structure was uneven and the sheet resistance was 8 mΩ /
As well as larger than □, the shape retention of the wiring was poor, and bleeding on the surface wiring layer and peeling were partially observed.

In contrast to these comparative examples, the wiring board of the present invention has a surface wiring layer having a low sheet resistance of 8 mΩ / □ or less and a high bonding strength of 3 kgf or more to the insulating substrate. I was able to.

Example 2 MnO ₂ was added to aluminum oxide powder (average particle size: 1.8 μm) at a ratio of 4% by weight and S
After adding and mixing 3% by weight of iO ₂ and 0.5% by weight of MgO, a slurry was prepared by further mixing an acrylic binder as an organic resin (binder) for molding with toluene as a solvent, It was formed into a sheet having a thickness of 250 μm by a doctor blade method. Then, a via hole having a hole diameter of 120 μm was formed at a predetermined location.

Next, with respect to 50 volume% of copper powder having an average particle size of 5 μm and 50 volume% of a main powder containing 50 volume% of W powder having an average particle size of 1 μm, a table having an average particle size of 1 μm was prepared. Various TiO ₂ , Cr ₂ O ₃ , Fe shown in 5 and 6
0.5 to 7 parts by volume of an oxide powder composed of ₂ O ₃ , NiO, and MnO _{2 in} terms of metal, and in some cases, an average particle size of 0.
5 μm Al ₂ O ₃ powder was mixed at the ratios shown in Tables 5 and 6, and an acrylic binder was used as a solvent in acetone to prepare a conductor paste.

Then, the above-mentioned conductor paste was printed and applied on the sheet-like molded body, and the via-hole conductor of each sheet-like molded body was also filled with the above-mentioned conductor paste for wiring layer. Each sheet-like molded body produced as described above was aligned and laminated and pressed to produce a molded laminate. Thereafter, the molded body laminate is placed in an oxygen-containing atmosphere substantially free of moisture (N
₂ + O ₂ or in the air) and then 1300 ° C
At a dew point of −10 ° C. in a mixed atmosphere of nitrogen and hydrogen.

The relative density of the insulating substrate in each of the prepared wiring boards is 99% or more, the thermal conductivity (thickness 3 mm) by the laser flash method is 18 W / m · K, and the volume resistivity is 10 ¹⁴ Ω · cm or more. Met.

After measuring the conductor resistance, length, width, and thickness of the wiring on the surface wiring layer of the wiring board,
The sheet resistance (mΩ / □) converted into a μm conductor was calculated. The structure was observed with a scanning electron microscope, and the particle size of W particles in the surface wiring layer was measured. Further, the joint strength of the metal fitting was measured in the same manner as in Example 1. The measurement results are shown in Tables 5 and 6.

[0060]

[Table 5]

[0061]

[Table 6]

As is clear from the results in Tables 5 and 6, Ti
O ₂ , Cr ₂ O ₃ , Co ₃ O ₄ , Fe ₂ O ₃ , MnO ₂
Even when an appropriate amount was added, the adhesion strength of the surface wiring layer to the insulating substrate was improved as compared with the case where no additive was added (Sample No. 1), but when the amount exceeded 5 parts by volume. And a decrease in sheet resistance was observed. Each of the surface wiring layers had a high bonding strength of 3 kgf or more, and no bleeding or peeling of the surface wiring layer was observed.

[0063]

As described above in detail, according to the present invention, a low-resistance surface wiring layer containing copper can be formed on the surface of an insulating substrate made of aluminum oxide by simultaneous firing with the insulating substrate. By including a specific transition metal in the surface wiring layer, the adhesion of the surface wiring layer to the insulating substrate can be improved. As a result, various metal fittings such as connection terminals are brazed to the surface wiring layer by brazing. Can be connected to

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of a multilayer wiring board of the present invention.

FIG. 2 is a diagram for explaining a method of measuring a bonding strength of a wiring layer in an example.

[Explanation of symbols]

1 insulating substrate 1a, 1b, 1c insulating layer 2a Surface wiring layer 2b Internal wiring layer 3 Via hole conductor 4 Plating layer 5 brazing material 6 Metal fittings

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H05K 3/46 H05K 3/46 ST H01L 23/12 C (56) References JP-A-7-15101 (JP, A) JP-A-6-223623 (JP, A) JP-A-5-144316 (JP, A) JP-A-9-142969 (JP, A) JP-A-60-113986 (JP, A) JP-A-8-81265 ( JP, A) JP-A-8-161931 (JP, A) JP-A-6-125153 (JP, A) JP-A-8-8503 (JP, A) JP-A-6-53354 (JP, A) Hei 8-186346 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H05K 1/09 H05K 3/46 H05K 3/12

Claims (9)

(57) [Claims] 1. An insulating substrate made of ceramics containing aluminum oxide as a main component and having a relative density of 95% or more, and formed on at least the surface of the insulating substrate by simultaneous firing with the insulating substrate. 70 to 70% by volume of tungsten (W) and / or molybdenum (Mo)
For 100 parts by volume of the main conductor component consisting of 0% by volume, T
selected from the group consisting of i, Cr, Mn, Fe, Co and Ni
And a surface wiring layer comprising at least one of the above tungsten and / or molybdenum particles dispersed in a matrix made of copper and containing at least one kind thereof in a metal conversion ratio of 0.01 to 5 parts by volume. A wiring board characterized by the above-mentioned. 2. The sheet resistance of the surface wiring layer is 8 mΩ / □.
The wiring board according to claim 1, wherein: 3. The wiring board according to claim 1, wherein a metal fitting is brazed to the surface wiring layer. 4. The wiring board according to claim 1, wherein said aluminum oxide ceramic contains a manganese compound at a ratio of 2.0 to 6.0% by weight in terms of MnO2. 5. The semiconductor device according to claim 1, wherein the surface wiring layer comprises the main conductor component (100).
2. The wiring board according to claim 1, wherein aluminum oxide or ceramics having the same composition as the insulating substrate is contained in a proportion of 0.05 to 2 parts by volume with respect to the volume. 6. The surface of a green sheet containing a ceramic component mainly composed of aluminum oxide is coated with copper (Cu).
With respect to 100 parts by volume of a main conductor component comprising 10 to 70% by volume of a metal-containing powder and 30 to 90% by volume of a tungsten (W) and / or molybdenum (Mo) -containing powder in terms of metal, Ti, Cr, Mn, Fe, Co and Ni
After printing and applying a conductor paste containing at least one kind of powder selected from the group of 0.01 to 5 parts by volume in terms of metal in the form of a circuit pattern, the green sheets were laminated, and A method for manufacturing a wiring board, comprising: sintering in a non-oxidizing atmosphere at 1500 ° C. to form a surface wiring layer on the surface of an insulating substrate made of aluminum oxide ceramic having a relative density of 95% or more. 7. The method according to claim 6, wherein a metal fitting is brazed to the surface wiring layer. 8. A ceramic component mainly containing aluminum oxide, a manganese compound with MnO ₂ in terms 2.
7. The method for producing a wiring board according to claim 6, wherein the content is 0 to 6.0% by weight. 9. The method according to claim 9, wherein the conductive paste is composed of the main conductive component (10).
7. The method for manufacturing a wiring board according to claim 6, wherein 0.05 to 2 parts by volume of aluminum oxide or a ceramic having the same component as that of the insulating substrate is contained with respect to 0 parts by weight.