JP2001313469A - Capacitor including wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor including wiring board which uses low temperature baked porcelain composition which can be made dense at a low temperature equal to or lower than 1000 deg.C and has both stable low permittivity and low dielectric loss, as an insulator layer, and uses dielectrics porcelain composition whose main component is barium titanate which can be baked at a temperature equal to or lower than 1000 deg.C in the atmosphere and has excellent dielectric characteristic, as a dielectric layer. SOLUTION: This capacitor including wiring board 1 has a capacitor part 3 constituted of dielectrics layers 6 whose main component is barium titanate (BaTiO3) and which is composed of dielectrics porcelain composition having the following factors or the like. (a) Main crystal of the dielectrics porcelain composition has a perovskite type. (b) Permittivity ε of the composition is at least 1000. (c) At least one kind out of Si component, B component, alkaline metal component, alkaline earth metal component, Bi component, Zn component, Cu component and Pb component is included as subcomponent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board with a built-in capacitor using a dielectric ceramic composition for a dielectric layer, which has a high dielectric constant .epsilon. In a high frequency range and can be fired at a low temperature of 1000.degree. About. Since it can be fired at 1000 ° C or less in the atmosphere, Ag can be used as an electrode material and fired at the same time.
A multilayer electronic component with a built-in capacitor such as a capacitor, a coupler, a low-pass filter, and a power amplifier substrate can be formed.
It is suitable for laminating and integrating with other low dielectric constant insulator porcelain compositions to form a ceramic package or an electronic component having a built-in capacitor.

[0002]

2. Description of the Related Art In order to cope with recent increases in signal processing speed and wiring density, it is necessary to incorporate passive circuit elements such as capacitors inside a wiring board. In addition, in order to reduce the transmission loss of electric signals as a wiring board, it is required that the wiring can be simultaneously fired at a firing temperature of 1000 ° C. or lower with a wiring made of a low-resistance metal such as Ag or Cu having a lower resistance. You. Further, the insulating layer itself needs to have a lower dielectric constant in order to suppress dielectric loss. On the other hand, a dielectric layer having a high dielectric constant is required.
In order to respond to such market demands, various studies have been made on low-temperature fired wiring boards that use a low-dielectric-loss glass-ceramic composition containing a specific crystal phase for the insulator layer and incorporate a capacitor with a laminated high-dielectric layer. Have been.

[0003] Japanese Patent Application Laid-Open No. 2-305490 discloses a capacitor-containing wiring board in which an insulator layer contains a crystal phase such as forsterite, monticelite, akermanite, and enstatite, and a dielectric layer contains barium titanate as a main component. JP-A-3-241724, JP-A-4-167
412 and JP-A-5-55079. Such a substrate with a built-in capacitor is obtained by firing at a high temperature of 1200 ° C. or more (exceeding the melting point of Cu or Ag). Therefore, the low-resistance metal C
The transmission loss of an electric signal cannot be reduced by using u or Ag.

On the other hand, a dielectric material containing barium titanate as a main component is fired at a high temperature of 1300 to 1500 ° C. However, a dielectric material that can be fired at a temperature (1000 ° C. or lower) at which inexpensive noble metal Ag can be used is more preferable. Accordingly, various studies have been made on the development of dielectric materials aiming at achieving both low-temperature firing and high dielectric constant.

[0005] Various dielectric materials have been studied in which barium titanate is added with an auxiliary component for facilitating sintering or improving dielectric properties. A dielectric material to which a Cu-based eutectic mixture is added is disclosed in JP-A-54-53300.
A dielectric material to which MgO and MnO are added is disclosed in JP-A-57-7.
No. 1866. ZnO, CdO, C
A dielectric material to which uO is added is disclosed in JP-A-61-255161.
No. 6,086,045. A dielectric material to which ZnO, Mn ₂ O ₃ , and CuO are added is disclosed in JP-A-1-192762. JP-A-5-6710 and JP-A-5-6711 disclose a dielectric material to which a predetermined Ba-B-Li-Si-based glass is added. SiO ₂ ,
A dielectric material to which Li ₂ O, B ₂ O ₃ or the like is added is disclosed in
218207, JP-A-4-264305,
It is disclosed in Japanese Patent Application Laid-Open No. 4-264306. By reducing the relative addition amount of barium titanate, ZnO, SiO
_2. Dielectric materials which can be fired at about 1000 to 1050 ° C. by adding a rare earth element or the like are disclosed in JP-A-57-170405, JP-A-60-124306, and JP-A-2-4.
No. 4,609, and JP-A-5-120915.

However, these firing temperatures are 1350-1.
Since the temperature is relatively high at about 000 ° C., the melting point is 1000
Ag, which is an inexpensive noble metal having a temperature of not more than ℃, cannot be used. Therefore, various studies have been made on the development of a dielectric material aiming at further low-temperature firing. Japanese Patent Application Laid-Open No. 57-160963 discloses a dielectric material which can be sintered by adding lithium fluoride to barium titanate at 1000 ° C. or lower. However, since they contain halogen, they may induce ion migration of Ag which is an electrode material.

As described above, it is difficult to obtain a dielectric material that can be fired at 1000 ° C. or lower using barium titanate. However, in view of industrially stable supply of raw materials, it is preferable to use commercially available barium titanate for 10
It is preferable that a dielectric material that can be fired at a temperature of 00 ° C. or lower can be obtained. If this becomes possible, it is possible to achieve both improvement in performance and reduction in price of the wiring board with a built-in capacitor.

[0008]

SUMMARY OF THE INVENTION
A low-temperature fired porcelain composition which can be densified at a low temperature and has both stable low dielectric constant and low dielectric loss is used for an insulator layer, and titanic acid which can be fired at 1,000 ° C or less in the atmosphere and has excellent dielectric properties An object of the present invention is to provide a wiring board with a built-in capacitor in which a dielectric ceramic composition containing barium as a main component is used for a dielectric layer. In particular, the present invention relates to a package with a built-in capacitor and a wiring board with a built-in capacitor suitable for an electronic component with a built-in capacitor that can be co-fired using Ag as an electrode material.

[0009]

According to a first aspect of the present invention, there is provided a dielectric ceramic composition comprising a dielectric layer containing barium titanate (BaTiO ₃ ) as a main component and firing at 1000 ° C. or lower in an air atmosphere. The gist is a wiring board with a built-in capacitor made of a dielectric ceramic composition satisfying predetermined requirements. Hereinafter, each constituent feature and the effects achieved by the entire invention will be described.

First, it is necessary that the wiring board has a built-in capacitor using a dielectric ceramic composition that can be fired at 1000 ° C. or lower in an air atmosphere. The firing in the air atmosphere is performed so as not to lower the dielectric properties of barium titanate. Firing at 1000 ° C. or less is performed using Au, Au / P
This is for enabling simultaneous firing with a low-resistance electrode material such as t, Au / Pd, Ag, Ag / Pt, and Ag / Pd.
When Ag is used, the temperature is preferably 960 ° C. or lower. Preferably it is 950 ° C or lower, particularly 900 ° C or lower.

The wiring resistance of the electrode material used for the wiring board with a built-in capacitor of the present invention is desirably 5 mΩ / □ or less in order to reduce the transmission loss of electric signals. Therefore, the amount of Ag, Au, and Pt added is 5% by mass or less.
It is preferable to use Ag / Pd in which the added amount of / Pt and Pd is 10% by mass or less. In particular, Ag and Au are preferably used. For the wiring board with a built-in capacitor,
g, and Ag / Pt, Ag / P
d and Au are preferably used. This is because transmission loss of an electric signal can be reduced while ensuring the solder resistance of the surface layer.

It is important that the dielectric ceramic composition constituting the dielectric layer of the wiring board with a built-in capacitor of the present invention does not substantially contain a halogen element. Examples of the halogen element include F, Cl, Br, and I, but none of these is preferable. When a halogen element (for example, F) is present,
Ag used for electrode material when humidity or applied voltage was applied
This is because ion migration (migration) is easily performed as ions, and insulation reliability is easily reduced. Here, "substantially not contained" means that the content of the halogen element contained in 100% by mass of the dielectric ceramic composition is 1% by mass or less. Preferably it is 0.5% by mass or less, more preferably 0.2% by mass or less. The halogen element may be contained within the range of “substantially not containing” as used herein.

It is important that the main component of the dielectric ceramic composition constituting the dielectric layer of the wiring board with a built-in capacitor of the present invention is perovskite-type barium titanate. Here, the “perovskite-type barium titanate” refers to a material in which the molar ratio of Ba, Ti, and O is approximately 1: 1: 3. The reason why “approximately 1: 1: 3” is used is that this is not necessarily the case of the stoichiometric composition (1: 1: 3). For example, the case where the molar ratio of Ba / Ti is not exactly 1 (eg, 0.95 to 1.05). Further, by adding the third component, part of the Ba site is Mg,
Substitution with Sr, Ca, etc., or partial Ti site with Nb,
In some cases, Zr, Sn or the like is substituted.

The perovskite-type barium titanate used as a raw material preferably contains Nb ₂ O ₅ at 2% by mass or less. 0.15% by mass of CoO or NiO
It is preferable to use the following. In addition, ZnO is 0.5
It is preferable to use one containing less than 10% by mass. It is preferable to use a perovskite-type barium titanate raw material powder containing at least one of these components. The dielectric characteristics can be improved.

In order to avoid the problem that the dielectric properties and the simultaneous sinterability become unstable due to the effect of the metal diffused during the simultaneous firing with the electrode material, barium titanate whose main component is perovskite is used from the raw material stage. Good to use. This is because stable dielectric properties and simultaneous sinterability can be obtained even when firing is performed simultaneously with an electrode material such as Ag.

Conventionally, in the case of a dielectric ceramic composition containing at least 80% by mass of barium titanate substantially containing no halogen element, a dielectric constant of ε1000 or more can be obtained by firing at 1000 ° C or less (especially 960 ° C or less). Is not known. However, the dielectric ceramic composition constituting the dielectric layer of the wiring board with a built-in capacitor of the present invention has a dielectric constant of 1000 or more even when baked at 1000 ° C. or less despite substantially not containing a halogen element. ε can be obtained. Therefore, the wiring board with a built-in capacitor of the present invention can use Ag-based or Au-based low melting point and low resistance metal as a wiring material, and can reduce transmission loss of an electric signal.

The low-temperature fired porcelain composition constituting the insulator layer of the wiring board with a built-in capacitor of the present invention is not particularly limited as long as it can be fired at 1000 ° C. or less, but has a dielectric constant ε of 15 or less, preferably 10 or less. And more preferably 7 or less. In particular, anorthite, garnite, forsterite, cordierite, diopsite, Sr
₂ MgSi ₂ O ₇ , Celsian, mullite, spinel, S
r- anorthite, enstatite, quartz, willemite (Zr ₂ SiO _4), labradorite, petalite, wollastonite, it is preferable to use a low-temperature fired ceramic composition to precipitate a specific crystalline phase such Jirukonoraito. In particular, 1
The inclusion of the specific crystal which can be stably present at a temperature of 000 ° C. or less is good in terms of the stability of the dielectric properties. By containing the specific crystal as the main crystal, it is possible to exhibit excellent dielectric properties in a high frequency region, suppress the diffusion of the surplus glass component to the capacitor part, and form a capacitor part having stable performance.

The insulating layer of the wiring board with a built-in capacitor according to the present invention is characterized in that a specific crystal is contained in an amount of 30 to 100% by mass of the insulating layer.
It is good to contain 99.7 mass% (preferably 40-80 weight%, more preferably 50-70 weight%). This is because the dielectric properties of the insulator layer can be improved. In particular, Sr ₂ M
The gSi ₂ O ₇ crystal may be contained as a main crystal phase in an amount of 20 to 100% by weight of all the specific crystal phases. In particular, 30-7
The content is preferably 0% by weight. The Sr ₂ MgSi ₂ O ₇ crystal has excellent dielectric properties in a high frequency range, a large coefficient of thermal expansion, and a high melting point of 1560 ° C.
It can be stably present in the following firing.

Further, the ceramic component is reduced to 0.1 in terms of oxide.
1 to 10% by weight (preferably 0.1 to 5% by weight, more preferably 0.1 to 3% by weight), and 0.1 to 10% by weight (preferably 0.1 to 5%) weight%,
The alkali metal component is more preferably 0.1 to 10% by weight (preferably 0.1 to 3% by weight),
-5% by weight, more preferably 0.1-3% by weight). This is because low-temperature firing can be performed without impairing the structure of the crystal phase of the specific crystal. In addition, other components may be contained in an amount of 40% by weight or less.

Here, it is preferable to use a calcined powder containing a specific crystal instead of using a glass powder as a starting material. By adding a small amount of sintering aid to the calcined powder containing specific crystals or coating by sol-gel method,
It is possible to solve problems such as crystallization variations that occur when using crystallized glass powder. It is preferable to use B ₂ O ₃ or an alkali metal oxide (particularly Li ₂ O) as the sintering aid. The addition amount is 20% by mass or less, preferably 10% by mass or less. The term “calcined product” refers to a raw material powder containing a predetermined component at 1000 to 1200 ° C. (preferably 1000 to 1150 ° C., more preferably 1000 to 11 ° C.).
(00 ° C.) and cooled to room temperature without quenching (decreasing the temperature by 20 ° C. or more per minute). 80% by weight or more (more preferably 90% by weight or more, especially 95% by weight)
(To 100% by weight) is preferably crystalline in terms of dielectric properties.

In the insulating layer of the wiring board with a built-in capacitor of the present invention, particles of a specific crystal having a long diameter of 20 μm or less are preferably dispersed. Preferred major axis is 15 μm or less,
A more preferred major axis is 10 μm or less, and still more preferably 5 μm.
m or less. The lower limit is 0.1 μm or more. Also,
The content of the crystal having the predetermined particle size is 30 to 99.
It is preferably 7% by weight, more preferably 30 to 70% by weight. When the particle size and the content are in the above ranges, a low-temperature fired porcelain composition having a low dielectric constant, a small dielectric loss, and a high thermal expansion is obtained.

In measuring the major axis, it is preferable to observe the structure of the lap section (so-called mirror-polished surface) of the sintered body. For example, it is convenient and easy to confirm using a photograph of a SEM image of 2000 times magnification. It is preferable that the major axis be a straight line connecting the two most distant points of one specific crystal particle and take the length.
Ten specific crystal grains are arbitrarily extracted from each photograph of the SEM image, and the average value is taken. For one sample, the same operation is performed at least at three or more locations, and the overall average value is taken as the major axis of the specific crystal grain.

The melting point exceeds 1000 ° C. (1100 to 1
(500 ° C., especially 1500 ° C. to 1800 ° C.) The wiring board with a built-in capacitor of the present invention having an insulator layer using a calcined powder containing a specific crystal can effectively and stably have dielectric characteristics when fired at 1000 ° C. or less. Can be manufactured. Also,
By reducing the content of the glass component in the insulator layer (20% by mass or less, preferably 10% by mass or less), the capacitor characteristics do not deteriorate due to the diffusion of the glass component into the dielectric layer during firing. .

The insulator layer of the wiring board with a built-in capacitor of the present invention has a dielectric constant ε of 7 or less, preferably 6.5 or less.
In particular, it is preferred that the transmission loss is adjusted to be 6.0 or less (usually 4 or more), because transmission loss of an electric signal due to dielectric loss can be reduced. Preferably, the Q × f value (the product of the no-load quality factor and the resonance frequency) is adjusted so as to be 3000 GHz or more, preferably 5000 GHz or more (usually 20,000 GHz or less). Specifically, it can be realized by appropriately optimizing the firing conditions and powder state according to the composition ratio. Usually, when glass powder is used as a starting material,
The dielectric constant ε exceeds 7. In the present invention, by using a calcined powder containing a specific crystal as a main crystal as a starting material, the dielectric constant ε is reduced to 7 or less, and
An excellent Q × f value of 000 GHz or more can be realized. The dielectric constant, the no-load quality factor and the resonance frequency are based on JIS R
1627, and Qu × f can be calculated from the no-load quality factor and the resonance frequency.

The insulating layer and the dielectric layer of the wiring board with a built-in capacitor of the present invention are preferably prepared so that the water absorption is 0.1% by mass or less. Further, the content is preferably set to 0.05% or less. This is because, even when a low-resistance metal material such as Ag or Cu is used for the wiring, the occurrence of problems such as ion migration can be effectively suppressed. This water absorption can be measured according to JIS C 2141. The “thermal expansion coefficient” is preferably set to 8 to 15 ppm / ° C. Furthermore, it is good to be 10-15 ppm / degreeC. This is because the reliability of mounting connection between the wiring board with a built-in capacitor and the printed wiring board can be improved. This coefficient of thermal expansion can be measured by a differential expansion type thermomechanical analyzer or the like.

The insulating layer has a flexural strength of 150 MPa.
It is better to prepare it as described above. In order to ensure the adhesion strength of the wiring and the strength of the substrate itself in mounting and the like, the pressure is preferably 180 MPa or more. By appropriately optimizing the sintering conditions and the state of the powder in accordance with the composition ratio and also adjusting the water absorption and the bending strength, it is possible to effectively increase the reliability of the wiring board. This flexural strength is measured according to JIS R
1601 can be measured.

The insulator layer of the wiring board with a built-in capacitor according to the present invention may contain a crystal other than a specific crystal such as a Sr ₂ MgSi ₂ O ₇ crystal as an auxiliary crystal. As the sub-crystal, SiO
_{A 2-} system crystal (especially α-quartz, cristobalite) is preferred. Further, it is preferable that Li ₂ Si ₂ O ₅ crystal is included.

The insulator layer of the wiring board with a built-in capacitor according to the present invention preferably contains a ceramic component, a boron component, and an alkali metal component as subcomponents. As the ceramic component, alumina, zirconia, spinel, garnite, anorthite, and forsterite are preferable. It is possible to improve the strength of the wiring board and stabilize the dielectric characteristics. In particular, alumina is preferably used. The boron component contributes to lowering the firing temperature and increasing the density.
Any material can be used as long as it becomes an oxide during the firing process.
₂ O ₃ is preferred. B or a metal boride that decomposes at 1000 ° C. or lower to release B ₂ O ₃ can be used.

The alkali metal component has the effect of promoting the densification of the sintered body during low-temperature firing. In particular, the Li component is effective. This is effective when the composition ratio of the calcined powder is SiO ₂ rich. Any material may be used as long as it becomes an oxide during the firing process, and particularly, Li ₂ O is preferable. Alternatively, lithium organic acid can be used. The alkali metal component is preferably contained as a crystal phase, but is more preferably contained as a glass phase at a grain boundary or the like.

Other than Li, it is preferable to use a Na component and a K component. Any material that can be converted into an oxide during the firing process may be used.
Particularly, Na ₂ O and K ₂ O are preferable. Alternatively, an organic acid salt can be used. In particular, it is most effective to use these together with the Li component. Since the sintered body can be densified with a smaller addition amount, migration of metal ions such as Ag as a wiring material can be further reduced, and dielectric loss can be reduced.

The content of specific crystals such as Sr ₂ MgSi ₂ O ₇ crystals is 30 to 99.7% by mass (preferably 40 to 80% by mass).
%, More preferably 50 to 70% by mass). It is possible to obtain a wiring board with a built-in capacitor excellent in dielectric characteristics, capacitor characteristics, strength, and simultaneous sinterability. When the content of the specific crystal is less than 30% by mass, the dielectric properties decrease. On the other hand, if the content exceeds 99.7% by mass, baking at 1000 ° C. or lower becomes difficult, so that simultaneous baking with low-resistance wiring such as Ag, which is a wiring material, becomes difficult.

The content of the subcrystal is 69.7% by mass or less (preferably 20 to 60% by mass, more preferably 30% by mass).
To 50% by mass). The content of sub-crystals is 0.1% by mass
If it is less than 7, the dielectric constant tends to be as high as around 7. On the other hand, if the content exceeds 69.7% by mass, it is difficult to bake at 1000 ° C. or lower, so that simultaneous baking with a low-resistance wiring such as Ag, which is a wiring material, becomes difficult.

The content of the ceramic component in terms of oxide is preferably 0.1 to 10% by mass. Stabilization of the dielectric properties of the wiring board can be promoted. As the ceramic component, alumina, zirconia, spinel and the like are preferable. In particular, alumina is preferred. When the content is less than 0.1% by mass, the stabilization of the dielectric properties cannot be effectively promoted. On the other hand, if the content exceeds 10% by mass, another crystal phase tends to precipitate, and the dielectric loss increases. A more preferred range is from 0.1 to 5% by mass. More preferably 0.1
３3% by mass.

The content of the boron component in terms of oxide is preferably 0.1 to 10% by mass. The firing temperature can be lowered and densification can be effectively achieved. Particularly, B ₂ O ₃ is preferable. If this content is less than 0.1% by mass, the densification of the insulator layer cannot be effectively promoted. If the content exceeds 10% by mass, the dielectric properties (particularly, dielectric loss)
And the capacitor characteristics deteriorate.
A more preferred range is from 0.1 to 4% by mass. More preferably, the content is 0.1 to 3% by mass.

The content of the alkali metal component in terms of oxide is preferably 0.1 to 10% by mass. The firing temperature can be lowered and densification can be effectively achieved. In particular, Li
_It is better to make 2O mandatory. This content is 0.1% by mass
If it is less than 1, the densification of the insulator layer cannot be effectively promoted. On the other hand, when the content exceeds 10% by mass, ion migration is likely to occur when a wiring board is manufactured, and the capacitor characteristics are deteriorated. A more preferred range is from 0.1 to 5% by mass. More preferably, the content is 0.1 to 3% by mass.

The insulator layer of the wiring board with a built-in capacitor according to the present invention comprises 70 to 99.7% by weight of a calcined powder containing a specific crystal.
0.1 to 10% by weight (calculated as oxide) of the ceramic component, 0.1 to 10% by mass (calculated as oxide) of the boron component, and 0.1 to 10% by mass (calculated as oxide) of the alkali metal component. ) May be fired in the range of 850 to 1000 ° C. By specifying the amount of the calcined powder in the insulator layer and the amount of each additive in terms of oxide, the dielectric constant of the insulator layer can be reduced and the capacitor characteristics of the dielectric layer can be further improved, and Ag and the like can be improved. The ion migration of the wiring material can be suppressed more effectively. As this calcined powder,
Sr ₂ MgSi ₂ O ₇ crystal, SrSiO ₃ crystal and MgSi
It is preferable to use a calcined powder containing at least one of O ₃ crystals as a main component.

Unlike the conventional case using crystallized glass, a specific crystal (for example, Sr ₂ MgSi ₂ O as a main crystal)
_Since the insulator layer is formed using a method of sintering the calcined powder containing ( ₇ crystals) with a sintering aid, variation in crystallization due to the diffusion metal can be suppressed. As a result, there is no difference in the degree of sintering between the metallized surface and the other portions, and there is an advantage that there is no problem of substrate warpage. In addition, since the content of the glass component in the insulator layer is small, the capacitor characteristics do not deteriorate due to the diffusion of the glass component into the dielectric layer during firing.

The invention according to claim 2 is characterized in that, in particular, Si
The gist is a wiring board with a built-in capacitor having a dielectric layer using a dielectric porcelain composition containing at least one of the component, the B component, and the alkali metal component. A wiring board with a built-in capacitor having a dielectric layer made of a dielectric ceramic composition containing a perovskite-type barium titanate as a main component substantially free of a halogen element is exposed to air at 1000
℃ or less and the dielectric constant ε is 1000
To achieve the above, the addition of these subcomponents is effective.

These subcomponents are added in the form of oxides, carbonates, organic metals, organic acid salts, borides, silicides and the like. Preference is given to adding oxides, carbonates and organic acid salts. Particularly, they are oxides and carbonates. Basically, it may be added in the form of an oxide by firing in an air atmosphere. However, if the effect as a sintering aid is obtained,
It need not necessarily be an oxide. In addition, B
Vitrification may be carried out together with the components and the Si component and added as a part of the glass component, or the subcomponent may be coated on the barium titanate surface by a sol-gel method.

As a preferred combination of the subcomponents, a composition system mainly composed of the B component (a system in which the B component occupies 40% or more in terms of oxide) is preferable. Specifically, B component system, (B component +
Alkali metal component), (B component + alkali metal component +
Si component) system. Alkali metals are Li, K, Na
Is good. Particularly, it is Li. K mainly with Li component,
Na may be added in combination.

It is most preferable that the component B is an essential component of the component. That is, it is particularly preferable that the B component contains a subcomponent that is essential and the subcomponent further contains at least one of a Si component and an alkali metal component. Firing at a lower temperature becomes possible. Regarding the insulator layer to be used and other constitutions, claim 1
Since it is the same as the invention of the above, the description is omitted here.

A third aspect of the present invention further includes a dielectric layer made of a dielectric ceramic composition containing at least one of an alkaline earth metal component, a Bi component, a Zn component, a Cu component, and a Pb component as subcomponents. The gist is a wiring board with a built-in capacitor. That is, with respect to the invention of claim 1, the alkaline earth metal component, Bi component, Zn component, Cu
And at least one of the Pb component. According to the invention of claim 2, at least one of the Si component, the B component, and the alkali metal component as a sub-component, and further, an alkaline earth component It contains at least one of a metal component, a Bi component, a Zn component, a Cu component, and a Pb component.

By including these subcomponents,
Low-temperature baking of the dielectric ceramic composition constituting the dielectric layer and further improvement of the dielectric characteristics can be achieved. As the alkaline earth metal component, a Mg component, a Ca component, and a Sr component are preferable. It is presumed that these components promote a property improvement of the dielectric ceramic composition by substituting a part of the Ba site of barium titanate. Bi component, Zn component,
The addition of the Cu component and the Pb component can also improve the dielectric properties.

These subcomponents are added in the form of oxides, carbonates, organic metals, organic acid salts, borides, silicides and the like. Preference is given to adding oxides, carbonates and organic acid salts. Particularly, they are oxides and carbonates. Basically, it may be added in the form of an oxide by firing in an air atmosphere. However, if the effect as a sintering aid is obtained,
It need not necessarily be an oxide. In addition, B
Vitrification may be carried out together with the components and the Si component and added as a part of the glass component, or the subcomponent may be coated on the barium titanate surface by a sol-gel method.

According to a fourth aspect of the present invention, there is provided a wiring board with a built-in capacitor, wherein the content of the subcomponent contained in the dielectric ceramic composition constituting the dielectric layer is specified. With respect to the content of barium titanate contained in the dielectric porcelain composition being 100% by mass, the subcomponent is contained in an amount of 20% by mass or less in terms of oxide. In terms of oxide conversion, the Si component is SiO ₂ , the B component is B ₂ O ₃ , and the alkali metal component is M ₂ O.
(Where M is an alkali metal element), the alkaline earth metal component is RO (where R is an alkaline earth metal element), the Bi component is Bi ₂ O ₃ , the Zn component is ZnO, the Cu component is CuO,
The Pb component is converted as PbO.

The content of the subcomponents in terms of oxide indicates the total amount of each component contained. The reason why the upper limit of the content of the subcomponent in terms of oxide is specified to be 20% by mass or less is that when the content of the subcomponent exceeds 20% by mass, the dielectric constant ε drops to less than 1000. The smaller the content, the more the decrease in the dielectric constant ε can be suppressed. It is preferably at most 15% by mass, more preferably at most 10% by mass.

Regarding the sub-component which makes the Si component essential,
The preferable range of the content of the Si component is 5% by mass or less. It is more preferably at most 3% by mass, still more preferably at most 1% by mass. When the content of the Si component exceeds 5% by mass, tan δ which is one of the desired characteristics is deteriorated,
It is not preferable because the firing temperature becomes high.

As for the sub-component which makes the B component essential,
A preferable range of the content of the component is 10% by mass or less. More preferably, it is 6.5% by mass or less, still more preferably 4% by mass or less. The content of the component B is 10% by mass.
Exceeding the range is not preferable because sintering becomes unstable due to foaming of the sintering aid component.

[0049] As for the auxiliary component which essentially contains an alkali metal component, the preferable range of the content of the alkali metal component is 10% by mass or less. More preferably 5% by mass
Or less, more preferably 3% by mass or less. If the content of the alkali metal component exceeds 10% by mass, the dielectric constant ε decreases, which is not preferable.

The mode of addition of the subcomponent is the same as that already described, and therefore will not be described here.

According to a fifth aspect of the present invention, there is provided a wiring board with a built-in capacitor having a dielectric layer comprising a dielectric ceramic composition containing specific amounts of a Si component, a B component and an alkali metal component as essential components. By defining the content of each essential component, low-temperature sintering at 950 ° C. or lower and dielectric properties can be achieved in a well-balanced manner. Since the conversion is in terms of oxide, the Si component is converted as SiO ₂ , the B component as B ₂ O ₃ , and the alkali metal component as M ₂ O (where M is an alkali metal element).

The upper limit of the content of the subcomponent in terms of oxide is 20% by mass or less. This is because, as described above, when the content of the subcomponent exceeds 20% by mass,
This is because the dielectric constant ε drops to less than 1000.
Preferably 15% by mass or less, more preferably 10% by mass
It is as follows.

The preferred range of the content of the Si component is 5% by mass or less. It is more preferably at most 3% by mass, still more preferably at most 1% by mass. If the content of the Si component exceeds 5% by mass, tan δ, which is one of the desired characteristics, is degraded and the firing temperature is undesirably increased.

The preferred range of the content of the component B is as follows:
It is preferably 10% by mass or less. More preferably, it is 6.5% by mass or less, still more preferably 4% by mass or less. If the content of the component B exceeds 10% by mass, sintering becomes unstable, such as foaming of the sintering aid component, which is not preferable.

The preferred range of the content of the alkali metal component is preferably 10% by mass or less. It is more preferably at most 5% by mass, further preferably at most 3% by mass. When the content of the alkali metal component exceeds 10% by mass, the dielectric constant ε
Is undesirably reduced.

The mode of addition of the subcomponent is the same as that described above, and will not be described here.

[0057]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a wiring board with a built-in capacitor of the present invention will be described.
A description will be given using the substrate for characteristic evaluation (Example 1) and the example (Example 2) shown in FIG. FIG. 1 is a sectional view showing an embodiment of a wiring board (1) with a built-in capacitor according to the present invention.
2 is an insulator layer, 3 is a capacitor part, 4 is a wiring layer, 5 is a via hole conductor, 6 is a dielectric layer, and 7 is a capacitor electrode.

Example 1 (1) Production and Evaluation of Dielectric A characteristic evaluation of the dielectric layer alone of the present invention is performed. Commercial Ba
TiO ₃ powder, B ₂ O ₃ powder, Li ₂ CO ₃ powder (however,
(In terms of Li ₂ O). A resin binder and ethanol are added to the mixed powder and mixed using a pot mill to obtain a slurry. The slurry is spray-dried to obtain a granulated powder.

This granulated powder was subjected to 80MP using a pressing machine.
Form into a plate at the pressure of a. This molded plate is 150 MPa
A molded product is obtained by a CIP method (cold isostatic pressing method) at a pressure of. This molded body was fired under the firing conditions (1000
(° C. or lower) to obtain a target sintered body.

This sintered body is evaluated as follows. First, the sintered body is made into a 58 mm square plate-shaped sample. A disc-shaped electrode having a diameter of 38 mm and a ring-shaped guard electrode having a diameter of 40 mm are formed on the surface of the electrode, and the electrode is also formed on the entire back surface. Impedance analyzer (HP4194A manufactured by Hewlett-Packard) and test jig (HP16451 manufactured by Hewlett-Packard)
Is used to measure the capacitance at a frequency of 1 MHz and a reference temperature of 25 ° C. The dielectric constant ε is calculated from the obtained capacitance and the sample size. Table 2 shows the results.

[0061]

[Table 1]

[0062]

[Table 2]

Each sample had a capacitance of 5000 pF.
As described above, the dielectric constant ε is a good result of 1000 or more. The water absorption was measured according to JIS C 2141, and all were less than 0.1%. Sample No. 13 containing 20% by mass of the subcomponent has a capacitance of 5071 pF and a dielectric constant ε of 1010. Therefore, it is understood that the content of the subcomponent is preferably 20% by mass or less. Examples in which the content of the Si component was 5% by mass in terms of SiO ₂ (sample number 7), and examples in which the B component was 10% by mass in terms of B ₂ O ₃ (sample numbers 4, 12) According to the results of Examples (Sample No. 21) in which the content of the alkali metal component is 10% by mass in terms of M ₂ O, all the samples have a capacitance of about 5000 to 6000 pF and a dielectric constant ε of about 5000 to 6000 pF. 1000
About 1300. Therefore, the content of the Si component is 5% by mass or less in terms of SiO ₂ , and the content of the B component is B ₂
It is understood that the content is preferably 10% by mass or less in terms of O _{3 and} the content of the alkali metal component is preferably 10% by mass or less in terms of M ₂ O.

(2) Investigation of Influence of Insulator on Dielectric First, calcined powder used for the insulator layer is prepared. The silica powder, magnesia powder, and strontium oxide powder are mixed at the ratios shown in Table 3. This powder is calcined at the calcining temperature shown in Table 4 for 2 hours.

The calcined product obtained was in the form of a powder and contained CuKα.
X-ray diffraction measurement using X-rays revealed that calcined products A, B and D
Was found to contain Sr ₂ MgSi ₂ O ₇ crystal, SrSiO ₃ crystal and α-quartz crystal. Further, the calcined products C and E are made of Sr ₂ MgSi ₂ O ₇ crystal, MgSiO ₃ crystal, Mg
It was found to contain ₃ SiO ₄ crystal and α-quartz crystal.

The alumina powder (Al ₂ O ₃ ), boron oxide powder (B ₂ O ₃ ), lithium oxide powder (Li ₂ O), sodium oxide powder (Na ₂
O) and potassium oxide powder (K ₂ O).
After adding the binder and ethanol, granulate and 80MPa
Press to form. Thereafter, isotropic isostatic pressing (CIP) treatment is performed at 150 MPa, and then firing is performed at a firing temperature shown in Table 4 in an air atmosphere.

Sample Nos. 37 to 41 obtained
Water absorption, thermal expansion coefficient, flexural strength, dielectric constant,
The five characteristics of the product of the load quality factor and the resonance frequency are as follows.
And measure. Table 5 shows the results. Water absorption: Measured according to JIS C 2141. Thermal expansion coefficient: The obtained sintered body has a diameter of 4 mm and a length of 20 m
m, and at 30-400 ° C., a differential expansion type thermal machine
Analytical equipment (Model “TMA8140” manufactured by Rigaku Corporation)
C "). Flexural strength: The obtained sintered body is 40 mm long and 3 m thick
m, grinding to 4 mm width, according to JIS R 1601
Measured by three-point bending strength. Dielectric properties: Parallel conductor plate type according to JIS R 1627
TE of dielectric resonator method ₀₁₁Resonant frequency 8 ~ depending on the mode
Measured at 9 GHz.

The surface of each sintered body was mirror-polished, and the surface was observed with a scanning electron microscope.
m Sr ₂ MgSi ₂ O ₇ crystal particles were observed.

Next, it is evaluated whether or not the dielectric layer has any effect on the capacitor characteristics when firing is performed with the dielectric layer sandwiched between the insulator layers. Combinations of the insulator layer and the dielectric layer are as shown in Table 6. Sample No. 42 to Sample No. 4 in Table 6
A slurry is prepared by adding an acrylic binder, a plasticizer, a dispersant, toluene, and methyl ethyl ketone to the mixed powders having the respective composition ratios, which is a combination of No. 6. This slurry is formed into a green sheet having a thickness of 300 μm using a known doctor blade method.

The green sheets of the dielectric layer are laminated so as to have a thickness of 3.4 to 4 mm after firing to form a laminate. A green sheet of an insulator layer having a thickness of 3.4 to 4 mm after firing is also laminated on both surfaces of the laminate. A binder removal treatment is performed at 250 ° C. in an air atmosphere. Then 900-950 ° C under nitrogen atmosphere
(Hold for 2 hours). Thereafter, the insulator layer is polished and removed while leaving the dielectric layer, to obtain a target substrate for property evaluation.

The substrate for characteristic evaluation is evaluated as follows. First, the sintered body is made into a 58 mm square plate-shaped sample. Φ38mm disk-shaped electrode on its surface and φ40m around it
An m-shaped guard electrode is formed, and an electrode is also formed on the entire back surface. Impedance analyzer (HP4194A, Hewlett-Packard) and test jig (HP164, Hewlett-Packard)
51), the capacitance is measured at a frequency of 1 MHz and a reference temperature of 25 ° C. The dielectric constant ε is calculated from the obtained capacitance and the sample size. Table 6 shows the results. From the results in Table 6, it can be seen that even when the insulating layer was sandwiched and fired, the capacitor characteristics of the dielectric layer were hardly affected.

[0072]

[Table 3]

[0073]

[Table 4]

[0074]

[Table 5]

[0075]

[Table 6]

(Example 2) An acrylic binder, a plasticizer, a dispersant, toluene, and methyl ethyl ketone are added to a mixed powder having a composition ratio of a combination of Sample Nos. 42 to 46 in Table 6 to prepare a slurry. This slurry is formed into a green sheet using a known doctor blade method. The thickness of the insulator layer is 120 μm and the thickness of the dielectric layer is 60 μm
And

A via hole having a diameter of 250 μm is formed at a predetermined position of these green sheets using a mold. An Ag paste is filled in the via hole and printed to form a via hole conductor. Thereafter, an Ag paste is printed in a predetermined pattern on the green sheet using a known screen printing method to form a wiring layer and a capacitor electrode. The printing thickness is 20 μm. The printed green sheets are pressure-bonded and laminated according to the combinations shown in Table 6 so as to have the configuration shown in FIG. 1 to form a laminate. A binder removal treatment is performed at 250 ° C. in an air atmosphere. Then under the air atmosphere 9
Baking at 00 to 950 ° C. (holding for 2 hours) to obtain a target substrate.

The amount of warpage of each of the obtained substrates (the maximum value of the amount of protrusion from the reference surface of the substrate; see FIG. 2) is measured using a surface roughness meter. Each of the warpage amounts was 50 μm or less, which was a good result.

[0079]

According to the present invention, there is provided a dielectric layer comprising a dielectric porcelain composition which can be fired at 1000 ° C. or less in the atmosphere using perovskite-type barium titanate and has excellent dielectric properties. A wiring board with a built-in capacitor can be provided. 1000 ° C or less, especially 950 ° C
Since firing is possible below, simultaneous firing is possible using Ag having a melting point of 961 ° C. as an electrode material. Therefore, it can be incorporated as a capacitor layer in another wiring board having an insulator layer made of a low-temperature fired ceramic composition that can be fired at 1000 ° C. or lower in the atmosphere. Further, an electronic component such as a multilayer capacitor can be formed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a wiring board with a built-in capacitor used in an embodiment of the present invention.

FIG. 2 is an explanatory diagram of a method for measuring the amount of warpage of a wiring board with a built-in capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Built-in capacitor wiring board 2 Insulator layer 3 Capacitor part 4 Wiring layer 5 Via hole conductor 6 Dielectric layer 7 Electrode for capacitor

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 23/12 N (72) Inventor Hidetoshi Mizutani 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan (72) Inventor Tsutomu Sakai 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan Inside (72) Inventor Shinji Suzumura 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Japan (72) Inventor Satoshi Iio 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi F-term (reference) 5E001 AB03 AE02 AE03 AE04 5E346 AA02 AA05 AA12 AA15 AA22 AA32 BB20 CC16 CC21 CC39 DD07 DD13 DD34 EE24 EE27 EE29 FF45 GG04 GG06 GG08 GG09 HH06 HH31

Claims (5)

[Claims] 1. A capacitor section comprising a dielectric layer, capacitor electrodes formed on the upper and lower surfaces of the dielectric layer to form a capacitor, and an insulation formed to sandwich the dielectric layer and the capacitor section. A wiring board with a built-in capacitor including a body layer, wherein the dielectric layer is a dielectric porcelain composition containing barium titanate (BaTiO ₃ ) as a main component and fired at 1000 ° C. or lower in an air atmosphere. A wiring board with a built-in capacitor, comprising a dielectric ceramic composition satisfying the requirements (a) and (b). (A) The main crystal of the dielectric ceramic composition is a perovskite type. (B) The dielectric constant ε is 1000 or more. 2. A capacitor portion comprising a dielectric layer, capacitor electrodes formed on the upper and lower surfaces of the dielectric layer to form a capacitor, and an insulation formed so as to sandwich the dielectric layer and the capacitor portion. A wiring board with a built-in capacitor including a body layer, wherein the dielectric layer is a dielectric porcelain composition containing barium titanate (BaTiO ₃ ) as a main component and fired at 1000 ° C. or lower in an air atmosphere. A wiring board with a built-in capacitor, comprising a dielectric ceramic composition satisfying the requirements (a) to (c). (A) The main crystal of the dielectric ceramic composition is a perovskite type. (B) The dielectric constant ε is 1000 or more. (C) As a sub component, at least one of a Si component, a B component, and an alkali metal component is contained. 3. The dielectric layer further comprises an alkaline earth metal component, a Bi component, a Zn component, a Cu component as subcomponents,
The wiring board with a built-in capacitor according to claim 1 or 2, wherein the wiring board contains at least one of Pb components. 4. The dielectric layer according to claim 2, wherein said subcomponent is 2% in terms of oxide with respect to 100% by mass of said barium titanate.
4. The wiring board with a built-in capacitor according to claim 2, wherein the wiring board contains 0% by mass or less. 5. 5. The content of the subcomponent contained in the dielectric layer in terms of oxide, which satisfies the following requirements (d) to (f).
The wiring board with a built-in capacitor according to any one of the above. However,
The case where (d) to (f) all become 0 is excluded. (D) The content of the Si component is 5% by mass or less in terms of SiO ₂ . (E) The content of the component B is 10% by mass in terms of B ₂ O _3.
Less than. (F) The content of the alkali metal component is 10% by mass or less in terms of M ₂ O. Here, M represents an alkali metal element.