JP2003163425A - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board which can deal with miniaturization and a thin shape, whose mechanical and electrical reliability is high an in which a conductor layer of high adhesion can be formed by a simultaneous firing operation, and to provide a method of manufacturing the wiring board. <P>SOLUTION: In the wiring board, conductor layers are formed on the inside and/or the surface of an insulating board composed of an alumina sintered compact in a minimum thickness of 0.6 mm or less. The sintered compact contains an auxiliary component of 4 to 15% by mass expressed in terms of an oxide. The auxiliary component exists in the grain boundary of an alumina main crystalline phase mainly as an insulating crystal, the mean particle diameter of the alumina main crystalline phase in the sintered compact is 0.5 to 4 μm, its mean porosity is 5% or less, its maximum pore diameter is 20 μm or less, and its mean pore diameter is 10 μm or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board having excellent electrical reliability, and in particular, for accommodating semiconductor elements, which is mainly composed of alumina excellent in low-temperature sinterability and can be made compact and thin. The present invention relates to a wiring board suitable for use in packages, multilayer wiring boards, and the like.

[0002]

2. Description of the Related Art In recent years, with the high integration of semiconductor elements and the miniaturization of electronic components, various electronic devices have been miniaturized and highly functionalized. Along with this, there has been a demand for downsizing and thinning of a ceramic package that houses a semiconductor element or mounts a passive component simultaneously with the semiconductor element.

With the downsizing or thinning of such ceramic packages, the substrate thickness is reduced to 0.6 mm.
In some cases, the following thickness is required. Therefore, in order to obtain high material strength, the thickness of the sintered body is 0.25 to 0.
3-point bending strength at 35 μm is 539 MPa (55 k
A high-strength alumina substrate having a gf / mm ² ) or more is disclosed
No. 0-7425 is proposed.

[0004]

[Patent Document 1] Japanese Unexamined Patent Application Publication No.
The high-strength alumina substrate described in Japanese Patent Application Laid-Open No. 000-7425 needs to be fired at a high temperature of 1550 ° C. or higher, and therefore cannot be fired at the same time as the conductor layer containing a low resistance metal.
As a result of requiring an extra step of baking only the substrate once and then forming the conductor layer, there is a problem that the cost becomes high.

Even when a conductor layer made of a refractory metal such as W or Mo is deposited, the strength of the conductor layer is deteriorated due to the progress of grain growth of W or Mo itself, and the conductor layer adheres to the insulating substrate. There is a problem that the property is low, and peeling and cracks occur to cause defects.

Since the substrate is as thin as 0.25 to 0.35 mm, the three-point bending strength is measured using this substrate.
Even if there are relatively large voids inside, the elastic deformation is large, so it shows a relatively high strength, but with regard to the electrical characteristics, even with a small amount of large voids, the effect is significant with thin samples, and the insulation properties deteriorate. However, there is a problem in that the electric breakdown is easy and electrical reliability is low.

Therefore, the present invention provides a wiring board which can be made compact and thin, has high mechanical and electrical reliability, and can form a conductor layer having high adhesion by simultaneous firing. With the goal.

[0008]

The present invention has excellent mechanical and electrical reliability by crystallizing the grain boundaries of a sintered body and controlling the structure and microstructure of the sintered body. It is based on the finding that a wiring board can be obtained, and as a result, deterioration of insulation and dielectric breakdown can be prevented even if miniaturization is performed, and a conductor layer with low resistance can be formed by simultaneous firing, which reduces reliability. A high wiring board can be provided.

That is, the wiring board of the present invention is a wiring board in which a conductor layer is formed inside and / or on the surface of an insulating board made of an alumina sintered body having a minimum thickness of 0.6 mm or less. Sintered body is 4-1 in terms of oxide
5% by mass of the auxiliary component is present, and the auxiliary component mainly exists as an insulating crystal in the grain boundary of the alumina main crystal phase, and
The alumina main crystal phase in the alumina sintered body has an average particle diameter of 0.5 to 4 μm, and an average porosity of 5% or less,
It is characterized in that the maximum pore diameter is 20 μm or less and the average pore diameter is 10 μm or less.

Further, the alumina-based sintered body contains alumina as a main component, and Mn is 1 to 10% by mass in terms of oxide, and S
i in an amount of 1 to 10% by mass in terms of oxide, and Mn ₃ Al ₂ Si ₃ O ₁₂ and / or M at the grain boundaries of the alumina main crystal phase.
It is preferable to include nAl ₂ O ₄ crystals. Thereby, stable structure control is possible, and the average particle size and pores can be stably kept within the above range.

Further, the content of the Group 4a metal element is preferably 0.1% by mass or less in terms of oxide. Thereby, the strength can be further improved.

It is also preferable that the conductor layer contains W and / or Mo as a main component and contains alumina. As a result, the alumina-based sintered body and the conductor layer can be fired at the same time, and it becomes possible to form a conductor layer having high adhesion strength with respect to the insulating substrate, and to seal the lid or connect various metal terminals. it can.

Further, the conductor layer is made of Au, Ag and C.
It is preferable to include at least one of u. Thereby, the electric resistance of the conductor layer can be reduced.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The wiring board of the present invention is a wiring board in which a conductor layer is formed inside and / or on the surface of an insulating substrate made of an alumina-based sintered body including a portion having a minimum thickness of 0.6 mm or less. It is important that the auxiliary component is contained in an amount of 4 to 15% by mass in terms of oxide.

When the amount of the auxiliary component is less than 4% by mass in terms of oxide, the content of alumina exceeds 96% by mass, the amount of liquid phase at the time of firing is small, and high temperature is required for producing an alumina sintered body. Firing is required, and as a result, conductor components such as W and M
It becomes impossible to co-fire the conductor layer containing o. On the other hand, if it exceeds 15% by mass, the content of alumina is less than 85% by mass, and it becomes difficult to sufficiently exhibit the excellent material properties as alumina. Particularly, electrical properties, dielectric properties, mechanical properties, thermal properties And so on.
In order to carry out more stable crystal structure control, the amount of the auxiliary component is preferably 5 to 13% by mass, more preferably 6 to 10% by mass in terms of oxide.

It is important that the above-mentioned auxiliary component exists mainly as an insulating crystal in the grain boundary of the alumina crystal of the main crystal phase. When the grain boundary phase has a small amount of an auxiliary component, lattice defects occur at the interface between the alumina main crystal phases, and as a result of the occurrence of cracks at the interface due to the anisotropy of the main crystals, these interfaces act as a conductive path, When the substrate is as thin as 0.6 mm or less, the insulating property of the substrate decreases and the risk of dielectric breakdown increases.

Further, when the grain boundary phase is amorphous, the heat dissipation property is deteriorated and the metal element is easily diffused, so that the deterioration of the characteristics due to the change of the insulating property with time and the long-term reliability becomes low. There is. Note that it is not necessary that all of the auxiliary components be insulating crystals, and the proportion thereof depends on the main crystal grain size and the thickness of the grain boundary phase, but at least a crystal that cuts off the conductive path is the main crystal grain. It only has to exist in the world.

Specific auxiliary components include Mn ₂ O ₃ and S.
Examples thereof include iO ₂ , ZrO ₂ , TiO ₂ , MgO, and CaO, and it is particularly preferable to contain Mn ₂ O ₃ and SiO ₂ .

According to the present invention, in order to improve the electrical reliability, the average particle size of the alumina main crystal phase is 0.5 to 4 μm.
Is important, and it is particularly preferable to control in the range of 0.8 to 3 μm, more preferably 1 to 2 μm. If the average particle size is less than 0.5 μm, the thermal conductivity decreases, and the thermal stress due to the difference in thermal expansion is repeatedly applied in the temperature cycle test, and the adhesion between the insulating substrate and the conductor layer deteriorates. If it exceeds the range, the defects and pores formed between the alumina main crystal grains become large, which causes electrical short-circuiting and characteristic deterioration in the portion where the substrate thickness is thin, and the strength of the alumina-based sintered body decreases.

The average porosity of the alumina-based sintered body is 5
% Or less, maximum pore diameter is 20 μm or less, average pore diameter is 10
It is important to make the thickness below μm. By obtaining the above relationship regarding the pores, the breaking strength of the miniaturized and thinned package is kept high, and even if the substrate becomes thin, the number of pores is small and the pores themselves are small. As a result, it is possible to suppress the reduction of the conductive path substantially, and as a result, it is possible to increase the dielectric strength voltage and prevent the deterioration of the electrical reliability due to the deterioration of the electrical characteristics and the change over time.

That is, when the average porosity exceeds 5%, the dielectric strength is lowered, and the strength and thermal conductivity of the alumina sintered body are lowered, and the maximum pore diameter exceeds 20 μm or the average pore diameter is 10 μm. If it exceeds, in addition to the decrease in withstand voltage and the decrease in strength, the electrical insulation deteriorates when a temperature cycle load is applied.

In order to further improve the electrical and mechanical reliability, the average porosity is particularly 3% or less, further 1% or less, and the maximum pore diameter is particularly 15 μm or less, further 10 μm or less, and The average pore diameter is 8 μm or less,
Further, it is preferably 6 μm or less.

Next, the present invention will be specifically described by taking a sintered body containing alumina as a main component and containing a Mn compound and a Si compound as a sintering aid as an example. When this composition is adopted, the lower limit value of alumina is preferably 85% by mass, particularly 87% by mass, and further preferably 90% by mass in order to facilitate the structure control and enhance the characteristics of the sintered body. Also, the upper limit is
In order to improve electrical reliability, it is preferably 96% by mass, particularly 95% by mass, and further 94% by mass. Therefore, the composition may be determined within the range of the above lower limit and upper limit.

As a sintering aid, first, as a first sintering aid, a Mn compound in terms of Mn ₂ O ₃ is 1 to 10% by mass, particularly 2 to 9% by mass, and further 3 to 8% by mass. Preferably 4 to
It is preferable that the content be 7% by mass. This is because the Mn component effectively acts as a sintering aid that enables firing at a low temperature, and if the amount of Mn ₂ O ₃ is less than 1% by mass, the denseness at 1350 to 1500 ° C. If Mn ₃ Al ₂ Si ₃ O ₁₂ and / or MnAl ₂ O ₄ is not easily precipitated at the grain boundaries of the main crystal, the sufficient electrical reliability is not achieved. Tends to not be able to get.

Si is used as a second sintering aid.
The content is preferably 1 to 10% by mass, particularly 2 to 9% by mass, further 3 to 8% by mass, and more preferably 4 to 7% by mass in terms of O ₂ . When the amount of SiO ₂ is less than 1% by mass, a liquid phase that contributes to sinterability is less likely to be generated.
Densification tends to be difficult to proceed, and when it is more than 10% by mass, Mn ₃ Al ₂ Si ₃ O ₁₂ and / or MnA
Since l ₂ O ₄ is less likely to be crystallized and the amorphous phase is increased, electrical properties, thermal properties, mechanical properties, etc. tend to be deteriorated.

These sintering aids are present as Mn ₃ Al ₂ Si ₃ O ₁₂ crystals and / or MnAl ₂ O ₄ crystals, which are insulating crystals, at the grain boundaries of the alumina main crystal grains, and the sintering aid The electrical reliability can be improved. Also, by crystallizing the above-mentioned sintering aid, the dielectric loss can be significantly reduced, and excellent electrical characteristics can be provided.

Further, as a third sintering aid, Mg, C
At least one of a, Sr and Ba may be contained in a proportion of 3% by mass or less in terms of oxide. By including these components, the simultaneous sinterability with the conductor layer can be improved. The auxiliary component in the present invention means M
It consists of n, Si, and a third sintering aid, and does not include the coloring components and Group 4a metal elements described below.

Further, if desired, a metal such as W or Mo may be contained in a proportion of 2% by mass or less as a coloring component for blackening the sintered body. Since this does not affect the sinterability, it is not considered as an auxiliary component in the present invention.

Further, since the Group 4a metal element is likely to exist as a compound that lowers the electrical insulation property, it tends to lower the withstand voltage or diffuse by electromigration to deteriorate the insulation property. The amount is preferably 0.1% by mass or less, particularly 0.05% by mass or less, and further preferably 0.01% by mass or less in terms of oxide. Since this does not affect the sinterability, it is not considered as an auxiliary component in the present invention.

As the group 4a metal element, TiO ₂ , Z
There are rO ₂ , HfO _2, etc., but especially TiO ₂ , ZrO
₂ is preferable in terms of increasing strength.

The wiring board of the present invention having such a structure has high strength, that is, 50 in order to improve mechanical reliability even when an impact or a stress is applied or a thermal stress is applied.
It is preferably 0 MPa or more, and particularly preferably 550 MPa or more. When the strength is set to 500 MPa or more, when the package is miniaturized, it is prevented from being damaged by thermal stress applied at the time of hermetically sealing or secondary mounting, and by the impact at the time of handling or use, thereby improving the mechanical reliability. It is possible to raise it. The strength in the present invention was evaluated by three-point bending strength at room temperature based on JIS 1601.

Further, according to the present invention, since the conductor layer is formed by simultaneously firing the alumina sintered body and the conductor layer having a strong adhesive force, a conductor containing W and / or Mo as a main component and containing alumina. It is preferable to form the layer on the surface and / or inside the insulating layer. This main component develops conductivity,
Alumina serves as a propagation path for electrical signals, and alumina reduces the difference in coefficient of thermal expansion, and can facilitate the sealing of the lid or the connection with various metal terminals.

Further, it is preferable to contain at least one of Au, Ag and Cu from the viewpoint of forming a conductor layer having a low electric resistance capable of reducing the conductor loss of a signal. Of these, Cu is most desirable in terms of high thermal conductivity and low cost.

In particular, in the conductor layer, the low resistance metal and the high melting point metal are 3:97 to 40:60, and particularly 10: 9.
It is preferable that they are compounded at a ratio of 0 to 35:65, further 20:80 to 30:70. By combining the low-resistance metal and the high-melting point metal, the high-melting point metal becomes the skeleton component of the conductor layer, so that the low-resistance metal does not volatilize even at the sintering temperature above the melting point of the low-resistance metal, and the electric resistance There is an advantage that a low conductor layer can be formed.

The wiring board having such a structure is excellent in electrical reliability and mechanical reliability, and has a feature that high adhesion can be obtained by simultaneous firing, and a ceramic package, an optical component and a power module are provided. It can be preferably used as a substrate for a substrate.

Next, a method for manufacturing the wiring board of the present invention will be specifically described.

First, as the raw material powder, the average particle diameter was 0.
Alumina powder of 5 to 2.5 μm, especially 1.0 to 2.0 μm is prepared. This is the lower limit of the average particle size is 0.5μ
By setting m, the sheet moldability can be facilitated and the cost increase of the powder can be prevented. Also, the upper limit is set to 2.
By setting the thickness to 5 μm, sintering can be facilitated at 1500 ° C. or lower.

Further, Mn ₂ O ₃ powder having an average particle size of 0.5 to 5 μm was prepared as the first sintering aid, and SiO ₂ powder having an average particle size of 0.5 to 3 μm was prepared as the second sintering aid. To do.
These raw material powders have a purity of 99 because of controlling impurities.
% Or more is preferable. In addition, Mn and Si are
In addition to the above oxide powders, carbonates, nitrates, acetates and the like that can form oxides by firing may be added.

These auxiliary components are 1 to 1 of Mn ₂ O ₃ powder and SiO ₂ powder with respect to alumina powder.
It is important to add it in an amount of 0% by mass, particularly 2 to 9% by mass, and further 3 to 8% by mass. It is preferable to add Mn ₂ O ₃ powder in order to enhance sinterability, and SiO ₂ powder in order to promote densification.

If desired, at least one of Mg, Ca, Sr, and Ba is used as a third sintering aid in an amount of 3% by mass or less in terms of oxide, and a coloring component is selected from transition metals such as W and Mo. 2 mass% of metal powder and oxide powder in terms of metal
You may add in the following ratios.

After appropriately adding an organic binder to the above-mentioned mixed powder, this is subjected to a pressing method, a doctor blade method,
A sheet-shaped molded body for forming an insulating layer is manufactured by a known molding method such as a rolling method or an injection method. For example, an organic binder or a solvent is added to the mixed powder to prepare a slurry, and then a green sheet is formed by a doctor blade method. Alternatively, an organic binder is added to the mixed powder, and a green sheet, which is a sheet-shaped molded body, is manufactured to have a predetermined thickness by press molding, roll molding or the like.

If desired, via holes having a diameter of 50 to 250 μm can be formed in the green sheet thus produced by a microdrill, a laser or the like.

Next, a conductor paste is prepared. It is preferable that the conductor paste uses W and / or Mo as a conductor component, and alumina powder is added to this. this is,
This is to improve the adhesion between the alumina sintered body and the conductor layer.
In order to improve the adhesion, powder of the same composition as the oxide ceramics component forming the insulating layer may be added in place of alumina powder, and oxide powder of Ni or the like may be added in an amount of 0.
It is also possible to add it in the ratio of 05 to 2 volume%. A binder and a solvent are added to these powders and mixed to prepare a conductor paste.

At least one of Au, Ag and Cu
A low resistance metal powder of seeds may be added to the above composition. That is, a conductor paste containing these low resistance metal powders and high melting point metal powders such as W and Mo can be prepared.

The conductor paste thus obtained is applied by printing onto each green sheet by a method such as screen printing or gravure printing to form a wiring pattern, and the conductor paste is filled in via holes if desired.

The firing atmosphere is preferably a non-oxidizing atmosphere so that the metal is not oxidized. Specifically, it is desirable to use nitrogen or a mixed gas of nitrogen and hydrogen. In particular, in order to suppress the diffusion of copper in the conductor layer, it contains hydrogen and nitrogen and has a dew point of + 30 ° C. or less, particularly +2.
A non-oxidizing atmosphere at 5 ° C. or lower is desirable. If desired, an inert gas such as argon may be mixed in the atmosphere.

If the dew point during firing is higher than + 30 ° C., the alumina sintered body 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. Since the resistance of the conductor is increased and the diffusion of copper is promoted, a dew point of + 30 ° C. or lower is desirable.

The wiring board manufactured by such a method has high electrical reliability and mechanical reliability and can obtain a strength of 500 MPa or more. Therefore, it is suitable for a small ceramic package, an optical component, a substrate for a power module and the like. Can be used for.

[0049]

EXAMPLES With respect to alumina powder having a purity of 99% and an average particle diameter of 1.8 μm, Mn ₂ O ₃ powder having a purity of 99% and an average particle diameter of 4.5 μm, S having a purity of 99% and an average particle diameter of 1.0 μm.
iO ₂ powder, purity 99.9%, W powder with average particle size 1.2 μm, purity 99.9%, Mo with average particle size 1.2 μm
Powder, purity 99.9%, average particle size 0.7 μm MgC
O ₃ powder, purity 99%, CaC with average particle size 1.3 μm
O ₃ powder, purity 99%, SrC with average particle size 1.0 μm
O ₃ powder, purity 99%, BaO with average particle size 1.0 μm
After mixing powder, Cr ₂ O ₃ powder having a purity of 90% and an average particle diameter of 1.2 μm and Co ₃ O ₄ powder having a purity of 90% and an average particle diameter of 0.5 μm in a ratio as shown in Table 1, An acrylic binder as a molding organic resin (binder),
After preparing a slurry by mixing toluene as a solvent,
A doctor blade method was used to form a sheet having a thickness of 200 μm to obtain a green sheet.

The green sheets obtained above were laminated to a predetermined thickness and degreased in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C., and subsequently, at a temperature rising rate shown in Table 2, 10
The temperature was raised from 00 ° C. to the maximum firing temperature, fired at the maximum firing temperature in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C. for 1 hour, and then cooled to 1000 ° C. at the rate shown in Table 2.

The grain boundary crystal phase of the obtained sintered body was identified by X-ray diffraction after crushing the sintered body. Further, the bulk density was measured by the Archimedes method, the same sample was crushed to measure the true density, and the average porosity was calculated from the ratio with the bulk density. Furthermore, the surface of the sintered body was mirror-polished with a diamond paste, and an image analyzer (LUZEX-F manufactured by Nireco) was used.
The maximum pore diameter and average pore diameter of the pores were measured using S). That is, the microscope magnification is 100 times and the measurement area is 9.0 ×.
10 ⁴ μm ² was measured at 10 points, and the average values of the maximum pore diameter and the average pore diameter were calculated.

As for the strength, a beam-shaped sample having a thickness of 3 mm, a width of 4 mm and a length of 40 mm was prepared and measured at room temperature by three-point bending strength based on JIS R1601, and the average value of 30 pieces was taken as the strength. did.

Further, the average particle diameter of the alumina main crystal phase is 100 from a 1000 times photograph by a scanning electron microscope.
The average particle size was determined by the intercept method using individual particles.

After measuring the insulation resistance of each sample by the three-terminal method based on JIS C2141,
The insulation resistance was measured again after 100 cycles of a temperature cycle test at 150 ° C., and the insulation resistance of 10 ¹⁰ Ω or more was evaluated as ◯ and less than 10 ¹⁰ Ω was evaluated as x.

The length is 60 mm, the width is 60 mm, and the thickness is 0.
A 32 mm substrate was placed in silicone oil, a voltage of 5 kV was applied in the thickness direction of the substrate, and the presence or absence of dielectric breakdown was confirmed. And, those which are not destroyed are indicated by ◯, and those which are destroyed are indicated by x, and shown in Table 2.

On the other hand, the green sheet produced in the same manner as above was punched to have a diameter of 200 μm.
A via hole was formed. Then, W powder and Mo powder having a purity of 99.9% and an average particle diameter of 1.2 μm, a purity of 99.
9%, Au powder with an average particle size of 0.8 μm, purity 99.9
%, Ag powder having an average particle diameter of 1.2 μm, purity 99%, Cu powder having an average particle diameter of 1.2 μm, purity 99%, alumina powder having an average particle diameter of 1.8 μm, and NiO powder having an average particle diameter of 1.0 μm. After preparing the composition shown in Table 1, an acrylic binder and acetone were mixed as a solvent to prepare a conductor paste, and the conductor paste was filled into the via holes of the green sheet by a screen printing method, and at the same time, the wiring pattern was formed. It was applied by printing. The wiring pattern was prepared to have a line width of 150 μm.

Each of the sheet-shaped compacts produced as described above was aligned and pressure-laminated to produce a laminate. Then, this laminated compact was degreased in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C. and then degreased in a nitrogen-hydrogen mixed atmosphere with a dew point of + 25 ° C., and subsequently at the temperature rising rate shown in Table 2. The temperature rises from 1000 ° C to the maximum firing temperature,
After firing for 1 hour in a nitrogen-hydrogen mixed atmosphere having a dew point of + 25 ° C. at the firing maximum temperature, the sample was cooled to 1000 ° C. at the rate shown in Table 2.

The conductor layer of the produced wiring board was observed with a scanning electron microscope, and the appearance of the conductor layer was evaluated as ◯ when there was no peeling or crack, and as x when there was some. The results are shown in Tables 1 and 2.
It was shown to.

[0059]

[Table 1]

[0060]

[Table 2]

Sample No. of the present invention. Each of Nos. 2, 5, 8, 10 and 13 to 29 had a strength of 520 MPa or more and an insulating property of 10 ¹⁰ Ω or more, which caused little deterioration, did not cause dielectric breakdown, and had a good conductor layer appearance.

On the other hand, in the case of Sample No. 3 having an amorphous grain boundary crystal phase, large average porosity, maximum pore diameter, and large average pore diameter, which are outside the range of the present invention. In No. 1, the strength was 320 MPa, the insulating property was deteriorated, the resistance was lowered, and the dielectric breakdown occurred.

Further, the sample No. outside the scope of the present invention in which the grain boundary crystal phase is amorphous was used. 6 and 12 have a strength of 430 MPa
Hereinafter, the deterioration of the insulating property was observed.

Further, sample No. 3 having a large average porosity, maximum pore diameter and average pore diameter, which are out of the range of the present invention. In Nos. 3, 7 and 9, the strength was low at 480 MPa or less, the insulation resistance was not deteriorated, and dielectric breakdown occurred. In addition, similar sample No. No. 4 had a small strength of 390 MPa, and the insulating property was deteriorated.

Furthermore, after being fired at 1550 ° C., the sample No. 1 having a large average crystal grain size of 5 μm, which is outside the range of the present invention, was used.
No. 11 had a low strength of 460 MPa, the conductor layer was easily peeled off, and the appearance was poor.

[0066]

EFFECT OF THE INVENTION The wiring board of the present invention can be formed by controlling the additive amount and the sintered body structure such as the average particle size of the alumina main crystal, the average porosity, the maximum pore size and the average pore size. It is possible to perform simultaneous firing of the high quality sintered body and the conductor layer at a firing temperature of 1500 ° C. or lower, and it is possible to improve electrical reliability and mechanical reliability, and as a result, mechanical and electrical reliability are obtained. It is possible to realize a high-performance compact ceramic package.

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/46 H05K 3/46 TC 04B 35/10 D (72) Inventor Masanobu Ishida 1-4 Yamashita-cho, Kokubun-shi, Kagoshima No. KYOCERA Co., Ltd. Research Institute F-term (reference) 4E351 AA07 BB01 BB24 BB26 BB31 CC12 CC22 CC31 CC33 DD04 DD05 DD06 DD17 DD31 GG02 GG06 4G030 AA07 AA08 AA09 AA10 AA17 AA22 CAA GA CA04 GA17 CA04 GA14 CA12 CA14 GA20 GA24 GA27 5E346 AA12 AA15 AA32 AA38 BB01 CC17 CC32 CC35 CC36 CC38 CC39 DD02 DD34 EE24 EE27 EE28 EE29 GG02 GG04 GG06 GG09 HH01 HH11 HH22 HH24

Claims (5)

[Claims] 1. A wiring board having a conductor layer formed inside and / or on the surface of an insulating substrate made of an alumina sintered body having a minimum thickness of 0.6 mm or less, wherein the alumina sintered body is converted into oxide. And 4 to 15% by mass of the auxiliary component, the auxiliary component mainly exists as an insulating crystal in a grain boundary of the alumina main crystal phase, and the average of the alumina main crystal phase in the alumina sintered body is Particle size is 0.5 to 4 μm,
A wiring board having an average porosity of 5% or less, a maximum pore diameter of 20 μm or less, and an average pore diameter of 10 μm or less. 2. The alumina-based sintered body contains alumina as a main component, contains Mn in an amount of 1 to 10% by mass in terms of oxide and Si in an amount of 1 to 10% by weight in terms of oxide, and comprises an alumina main crystal. Mn ₃ Al ₂ Si ₃ O ₁₂ and / or MnAl _{2 at} the grain boundary of the phase
The wiring board according to claim 1, comprising an O ₄ crystal. 3. A metal element of Group 4a of 0.1 in terms of oxide.
The wiring board according to claim 1, wherein the wiring board is contained in a proportion of not more than mass%. 4. The conductor layer according to claim 1, wherein the conductor layer contains W and / or Mo as a main component and contains alumina.
The wiring board according to any one of 1. 5. The wiring board according to claim 1, wherein the conductor layer contains at least one of Au, Ag and Cu.