JP2002053368A - Porcelain excellent in high frequency characteristics and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: To produce by firing at 1000 ° C or less.
And co-firing with low-resistance conductors of gold, silver and copper.
And high porcelain strength, even in the high frequency range
To provide high frequency porcelain with low dielectric loss. SOLUTION: The constituent component is SiO₂, Al
₂O₃, MgO, ZnO and B ₂O₃Containing porcelain smell
And ZnO and Al₂O₃30-50 weight of crystalline phase containing
%, SiO₂And a crystal phase containing MgO in an amount of 5 to 15% by weight,
Substantially SiO₂Or SiO₂And B₂O₃Non consisting of
40 to 60% by weight of a crystalline phase and SiO₂Crystal phase
Is suppressed to 6% by weight or less, and 60 GHz
Dielectric loss of 15 × 10^-4It is characterized by the following
I do.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of co-firing with porcelain having excellent high-frequency characteristics (hereinafter sometimes referred to as high-frequency porcelain), particularly low-resistance conductors such as copper and silver. Various devices that transmit high-frequency signals such as waves and millimeter waves,
For example, semiconductor element storage package, dielectric resonator, LC
The present invention relates to a high-frequency porcelain suitable as a high-frequency wiring substrate or an insulating substrate used for a filter, a capacitor, a dielectric waveguide, a dielectric antenna, and the like.

[0002]

2. Description of the Related Art Conventionally, as a ceramic multilayer wiring board, a ceramic wiring board in which a wiring layer made of a refractory metal such as tungsten or molybdenum is formed on the surface or inside of an insulating substrate made of an alumina sintered body has been most widely used. ing. Also, recently, in the advanced information age, the frequency band used is shifting to higher frequency. In such a high-frequency wiring board, in order to transmit a high-frequency signal without loss, it is required that the resistance of the conductor forming the wiring layer is small and the dielectric loss of the insulating substrate in the high-frequency region is small. However, conventional refractory metals such as tungsten (W) and molybdenum (Mo) have large conductor resistance,
The signal propagation speed is low, and signal propagation in a high frequency region is also difficult. For example, in a high-frequency wiring board to which a high-frequency signal in a millimeter-wave region of 30 GHz or more is applied, the above-mentioned high-melting-point metal cannot be used, and instead of these high-melting-point metals, low-melting metals such as copper, silver, and gold are used. It is necessary to use resistive metal. However, since these low-resistance metals have low melting points and cannot be co-fired with ceramics such as alumina, wiring boards using glass ceramics, which is a composite material of glass and ceramics, as an insulating substrate are being developed. is there.

For example, Japanese Patent Application Laid-Open No. Sho 60-240135 discloses a method in which a zinc borosilicate glass to which a filler such as Al ₂ O ₃ , zirconia, or mullite is added is co-fired with a low-resistance metal. A multilayer wiring board has been proposed, and JP-A-5-298919 proposes a glass ceramic material in which mullite or cordierite is precipitated as a crystal phase.

[0004] On the other hand, depending on the use of the wiring board,
Various electronic components and input / output terminals are connected.
Cracks are generated on the wiring board due to the stress applied in the subsequent process.
Or the wiring board may be damaged. This
In order to prevent inconveniences such as
Plates are required to have high mechanical strength. There
The present applicant has previously disclosed in Japanese Patent Application Laid-Open No. 10-275963.
Porcelain with excellent mechanical strength and high frequency characteristics
Suggested. This porcelain consists of ZnO and Al₂O₃Including
Spinel type crystal phase and SiO₂Crystal phase and enstaty
And a crystalline phase, and substantially₂Or SiO
₂And B₂O₃Containing an amorphous phase consisting of
High mechanical strength and high dielectric loss
Small and extremely useful as an insulating substrate for high-frequency wiring boards
It is for. Such porcelain is made of SiO₂, Al₂O₃,
MgO, ZnO and B ₂O₃Contains in a specific ratio
Glass powder, ZnO powder and amorphous silica powder
Add the organic binder to the raw material mixture
And use this slurry to form a green sheet
And the obtained green sheet was heated at 825 to 975 ° C.
It is obtained by firing.

[0005]

However, Japanese Unexamined Patent Publication No.
The glass ceramics disclosed in JP-A-240135 and JP-A-5-298919 generally have a dielectric loss in a high frequency band even if they can be co-fired with a low-resistance metal such as copper, silver, or gold. It has the drawback of high mechanical strength and low mechanical strength. For example, the strength of the above-mentioned glass ceramic sintered body is about 15 kg / mm ^2, which is lower in each stage than that of the alumina-based sintered body.

On the other hand, the porcelain disclosed in Japanese Patent Application Laid-Open No. 10-275963 has a high mechanical strength, but has a problem of high thermal expansion (for example, its thermal expansion coefficient is 8 ppm / ° C). That is, there is a large difference in thermal expansion from a high-frequency device such as a GaAs chip or a SiGe chip used in a high-frequency band such as a microwave or a millimeter wave (the coefficient of thermal expansion is 5 to 8 ppm / ° C.).
For this reason, the wiring board provided with the insulating substrate formed by the porcelain has a thermal stress at the interface between the high-frequency element and the insulating substrate due to heat generated by the operation of the high-frequency element and heat generated when the high-frequency element is mounted. And as a result, there is a problem that cracks and the like occur. Also, this porcelain
In terms of dielectric loss in a high-frequency region, it was not sufficiently satisfactory.

Therefore, an object of the present invention is to provide a method of manufacturing by firing at a temperature of 1000 ° C. or less, enabling simultaneous firing with low-resistance conductors of gold, silver, and copper, a high porcelain strength, and a high frequency range. Another object of the present invention is to provide a high-frequency ceramic having a low dielectric loss and a method for manufacturing the same. Another object of the present invention is to provide a high-frequency wiring board provided as an insulating substrate formed by the high-frequency porcelain.

[0008]

The present inventors have studied in detail the porcelain disclosed in Japanese Patent Application Laid-Open No. Hei 10-275963 proposed by the present applicant.
Since SiO ₂ crystals such as quartz are precipitated in a large amount (for example, 10% by weight or more), they show a high coefficient of thermal expansion and high dielectric loss in a high frequency region (for example, 60 GHz), and the amount of precipitated SiO ₂ crystals Have found a new finding that they depend on the amount of impurity metal contained in the raw material of amorphous silica used as the raw material, and have completed the present invention.

According to the present invention, SiO 2
₂ , in a porcelain containing Al ₂ O ₃ , MgO, ZnO and B ₂ O ₃ , the crystal phase containing ZnO and Al ₂ O ₃ is 30 to
5 to 15% by weight of a crystalline phase containing SiO ₂ and MgO
% By weight, substantially 40 to 60% by weight of an amorphous phase composed of SiO ₂ or SiO ₂ and B ₂ O ₃ ,
The content of the _two crystal phases is suppressed to 6% by weight or less.
A porcelain excellent in high-frequency characteristics characterized in that a dielectric loss at 0 GHz is 15 × 10 ⁻⁴ or less. According to the invention, it is also possible to use SiO ₂ , Al ₂ O ₃ , MgO,
Raw material for crystallization and glass 65-85 wt%, and 5 to 20 wt% of ZnO powder, and 1 to 20% by weight content of impurities less amorphous silica powder 500ppm by metal basis containing ZnO and _B 2 _{O 3} Preparing a mixture, adding a organic binder to the mixture to prepare a slurry,
A method for producing porcelain having excellent high-frequency characteristics, comprising molding the slurry, subjecting the obtained molded body to a binder removal treatment, and then firing at 800 to 1000 ° C. According to the present invention, there is further provided a high-frequency wiring board comprising: an insulating substrate formed from the above-described porcelain; and a wiring layer formed on the surface and / or inside of the insulating substrate and capable of transmitting a high-frequency signal having a frequency of 1 GHz or more. Is provided.

The present invention relates to an improvement of the porcelain disclosed in Japanese Patent Application Laid-Open No. 10-275963, and the high-frequency porcelain of the present invention has a SiO ₂ crystal content of 6% by weight or less. In this respect, the porcelain is greatly different from the above-mentioned prior art porcelain. Since the content of the SiO ₂ crystal is suppressed, the dielectric loss at 60 GHz is 15 × 10 5 as shown in an experimental example described later. ⁻⁴ or less, and the coefficient of thermal expansion from room temperature to 400 ° C. is 5
８8ppm / ℃, GaAs chip or SiG
It is similar to that of a high-frequency element such as an e-chip. As a result, the high frequency porcelain of the present invention can be used very effectively as an insulating substrate of a high frequency wiring board. That is, the high-frequency porcelain of the present invention is made of SiO ₂ ,
Manufactured using a mixed powder of a crystallized glass containing Al ₂ O ₃ , MgO, ZnO and B ₂ O ₃ , a ZnO powder, and an amorphous silica powder, aluminum, iron, and iron contained in the amorphous silica powder are used. Metals such as antimony and antimony and other impurity metal oxides have a great effect on the precipitation of SiO ₂ crystals such as quartz. Specifically, when the amount of these impurities contained in the amorphous silica powder is large, the crystallization of the amorphous silica is promoted during firing, a large amount of SiO ₂ crystals are precipitated, and the coefficient of thermal expansion of the obtained porcelain becomes high. In addition, the dielectric loss in the high frequency region also increases. However, according to the present invention, by using high-purity amorphous silica in which the amount of impurities is suppressed to 500 ppm or less in terms of metal, crystallization of amorphous silica during firing is suppressed, and the SiO ₂ crystal content is reduced to 6%. It is possible to obtain a porcelain whose weight is suppressed to not more than% by weight.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to specific examples shown in the accompanying drawings. FIG. 1 is a schematic diagram for explaining the structure of the high-frequency porcelain of the present invention. FIG.
1 is a schematic cross-sectional perspective view of a high-frequency wiring board including a dielectric antenna, which is an example of a high-frequency wiring board using the high-frequency ceramic of the present invention. FIG. 3 is a schematic cross-sectional perspective view of a high-frequency wiring board including a dielectric antenna having a structure different from that of FIG. 2 which is an example of a high-frequency wiring board using the high-frequency ceramic of the present invention. FIG. 4 is a schematic side sectional view of a package for housing a semiconductor element as another example of a high-frequency wiring board using the high-frequency ceramic of the present invention.

(High frequency porcelain) The high frequency porcelain of the present invention comprises:
As essential components, SiO ₂ , Al ₂ O ₃ , Mg
It contains O, ZnO and B ₂ O ₃ , and usually contains these oxides in the following proportions. SiO _2: 30 to 60 wt%, in particular 40 to 50 wt% _Al 2 _O 3: 18~25 wt%, in particular 20 to 25 wt% MgO: 5 to 10 wt.%, Particularly 8-9 wt% ZnO:. 5 to 35 wt%, in particular 10 to 20 wt% _B 2 _O 3: 5~10 wt%, in particular 5.5 to 7% by weight according RF porcelain composition, as shown in FIG. 1, various crystalline phase and amorphous 1 (G in FIG. 1), and the crystal phase includes ZnO and Al ₂ O ₃ (indicated by SP in FIG. 1), and a crystal phase including SiO ₂ and MgO (FIG. 1). (Indicated by E in FIG. 1) is essential.

The crystal phase containing ZnO and Al ₂ O ₃ (S
As P), for example, a garnite crystal phase (ZnAl ₂ O)
₄ ), and a spinel-type crystal phase such as a (Zn, Mg) Al ₂ O ₄ crystal phase, and a garnite crystal phase is particularly preferable. In the present invention, such a crystal phase (S
P) is contained in an amount of 30 to 50% by weight. If this amount is less than 30% by weight, it is not possible to achieve both high strength and low dielectric loss of the porcelain, and if it is more than 50% by weight, the coefficient of thermal expansion of the porcelain will increase. Si
Examples of the crystal phase (E) containing O ₂ and MgO include an enstatite-type crystal phase such as an enstatite crystal phase (MgSiO ₃ ), a clinoenstatite crystal phase, a protoenstatite crystal phase, and a forsterite crystal phase. In particular, an enstatite type crystal phase is desirable in terms of reducing dielectric loss in a high frequency band and increasing strength of porcelain. In the present invention, the content of the crystal phase (E) is set in the range of 5 to 15% by weight. 5% by weight
If it is less than the above, the effect of reducing the dielectric loss of the porcelain will be insufficient, and if it is more than 15% by weight, the coefficient of thermal expansion of the porcelain will increase.

In the present invention, as shown in FIG. 1, an SiO ₂ crystal phase (indicated by Si in FIG. 1) such as quartz or cristobalite may be precipitated.
It is extremely important that the content of such a crystal phase (Si) is suppressed to 6% by weight or less. That is, when the deposition amount of the SiO ₂ crystal phase (Si) is more than 6% by weight, the dielectric loss in the high frequency region increases, and the thermal expansion coefficient of the porcelain increases, and the mounting reliability of the high frequency element decreases. Would. In order to set the precipitation amount of the SiO ₂ crystal phase (Si) within the above range, it is only necessary to use, as an amorphous silica powder to be described later, a high-purity amorphous silica powder in which the amount of impurity metal is suppressed to a certain value or less. In addition, a trace amount of impurity metals (Al, Fe, Sb) contained in the high-purity amorphous silica powder
Etc.) usually forms a solid solution in any of the above crystal phases, for example, a spinel type crystal phase (SP).

In the present invention, a willemite crystal phase represented by Zn ₂ SiO ₄ (not shown) is deposited in accordance with the composition of the crystallized glass used for precipitating the above-mentioned crystal phase. However, it is preferable that the amount of the precipitated willemite crystal phase is suppressed to 6% by weight or less from the viewpoint of reducing the dielectric loss and the coefficient of thermal expansion in the high frequency region. Further, in addition to the various crystal phases described above, other crystal phases such as a crystal phase represented by Mg ₂ B ₂ O ₅ (not shown) and a cordierite crystal phase (not shown) can be precipitated. The precipitation amount of such another crystal phase is 3 in total.
It is desirable that the content be not more than weight%.

The amorphous phase (G) is substantially composed of SiO 2
₂Or SiO₂And B₂O₃It consists of
This amorphous phase (G) is 40 to 60% by weight, especially 45 to 60% by weight.
It is present in a proportion of 55% by weight. Such an amorphous phase
Due to the presence of (G), dielectric loss of porcelain in high frequency band
Can reduce the dielectric constant of porcelain.
You. For example, in the amorphous phase (G), the various types
Included in crystallized glass used to precipitate crystal phase
Al₂O₃, ZnO, MgO, etc. (SiO 2 ₂Passing
And B₂O₃Component), the amorphous phase (G)
Dielectric loss in the high frequency band of the porcelain
The dielectric loss in the frequency band also increases. Therefore, amorphous
These components (SiO) in phase (G)₂And B₂O₃Other than
Component) is 50 ppm or less, respectively, and the total amount
At 100 ppm or less, such as
The components should precipitate in substantially all as a crystalline phase.

In the amorphous phase (G), the content of B ₂ O ₃ is 10 from the viewpoint of reducing the dielectric loss of the porcelain.
The content is preferably 0 ppm or less, particularly preferably 50 ppm or less, and most preferably the amorphous phase (G) is substantially formed of only SiO ₂ . That is, B ₂ O ₃ is
It is contained in the crystallized glass used as a raw material, and is crystallized as Mg ₂ B ₂ O ₅ upon firing, or is dissolved in the above-mentioned various crystal phases, particularly in the enstatite crystal phase (E). It is desirable to do.

The high-frequency porcelain of the present invention containing each of the main crystal phase and the amorphous phase as described above has not only high strength but also a dielectric constant of 6 or less and a dielectric loss (tan δ) at 15 GHz. Is as low as 10 × 10 ⁻⁴ or less.
The dielectric loss (tan δ) at GHz is not more than 15 × 10 ⁻⁴ , particularly not more than 10 × 10 ⁻⁴ ,
The coefficient of thermal expansion at 0 ° C. is in the range of 5-8 ppm / ° C.,
It is very close to the coefficient of thermal expansion of a semiconductor element such as a GaAs chip. Therefore, the high-frequency porcelain of the present invention is extremely useful as an insulating substrate of a high-frequency wiring board.

Further, in the high frequency porcelain of the present invention, the Co component as a component other than the above is 0.05 to 0.05 in terms of CoO.
It may contain 5% by weight, especially 0.1 to 2.0% by weight. Such a Co-containing porcelain is extremely useful for a wiring substrate provided with a Cu wiring layer.

That is, Cu, Ag, and Au are typical examples of the low-resistance conductor forming the wiring layer, but Cu and Ag are generally used in terms of cost. Among them, the Ag wiring layer can be formed by baking in the air, and it is not necessary to form a plating layer on the surface, which is particularly advantageous in terms of cost. There is a problem in solder wettability. For this reason, a Cu wiring layer that does not have such a problem is most commonly used. However, the Cu wiring layer has a Ni—
It is necessary to form a plating layer such as Au or Cu-Au.
By the way, when the insulating substrate in the wiring substrate is formed by a conventionally known porcelain, when the above-mentioned plating layer is formed on the surface of the Cu wiring layer, Au adheres to the surface of the insulating substrate, and discoloration and the space between the wiring layers are caused. There is a possibility that insulation may be deteriorated. The above-described porcelain containing a Co component has an advantage that Au adhesion during the formation of the plating layer as described above can be effectively prevented. In this case, when the Co content increases, the dielectric loss may increase, and when the Co content is low, the Au adhesion preventing effect may not be sufficiently exhibited. Therefore, the Co content is preferably set in the range described above.

The above-mentioned Co component is present in various crystal phases and amorphous phases in porcelain, especially in the form of CoO.
In particular, the distribution of Zn in the porcelain and the distribution of Co are in good agreement with each other, which indicates that Au is effectively prevented from being deposited due to the fact that part of Zn in the crystal phase is replaced by Co. The present inventors presume that this may be the case. From this, the Co component contains at least ZnO and Al ₂ O ₃
Is preferably contained in a crystal phase (SP) containing the following and an amorphous phase (G). Further, it is preferable that the Co component is uniformly dispersed in the porcelain. If a part of the Co component aggregates in the porcelain and the dispersion is non-uniform,
Aggregation of the Co component may cause an increase in dielectric loss, and baking may cause protrusion-like defects. The porcelain in which the Co component is uniformly dispersed exhibits a vivid color. For example, when evaluated by the L * a * b color system, lightness L *> 80 saturation C * = ｛(a *) ² + (B *) ² ｝ ^1/2 > 20.

(Production of high frequency porcelain) Raw material powder The raw material powder used for producing the high frequency porcelain of the present invention is a mixed powder of crystallized glass powder, ZnO powder and amorphous silica powder (fused silica). Is used.

The crystallized glass powder is made of SiO ₂ , Al ₂ O ₃ , MgO,
It contains ZnO and B ₂ O ₃ as components,
The amorphous phase in the porcelain is substantially SiO ₂ or SiO ₂
And B ₂ O _3, and preferably has the following composition in order to crystallize the remainder. SiO _2: 40 to 52 wt%, in particular 45 to 50 wt% _Al 2 _O 3: 14~32 wt%, in particular 25 to 30 wt% MgO: 4 to 15% by weight, in particular 9-13 wt% ZnO:. 6 to 16 wt%, in particular 6-10 wt% _B 2 _O 3: 5~15 wt%, such crystallized glass powder, especially 7 to 11 wt%, 1 to 10 [mu] m, especially an average particle diameter of 1.5~4μm It is preferable that the average particle size of the ZnO powder is in the range of 0.5 to 5 μm, particularly 0.8 to 2.5 μm.

Also, amorphous silica (fused silica)
As the powder, an extremely high-purity powder in which the total amount of impurity metals such as aluminum, iron, and antimony contained in the raw material sodium silicate or the like or mixed in the production process of amorphous silica is controlled to 500 ppm or less in terms of metal. Is used. That is, by using such high-purity amorphous silica (fused silica) powder, crystallization of amorphous silica during firing is effectively suppressed,
The precipitation amount of the SiO ₂ crystal phase is suppressed to the above-described range, and the dielectric loss in a high frequency region can be reduced. In addition, since the amount of the precipitated SiO ₂ crystal phase is suppressed, the coefficient of thermal expansion of the obtained porcelain from room temperature to 400 ° C. is in the range of 5 to 8 ppm / ° C., and the thermal expansion of semiconductor elements such as GaAs chips. Very close to the coefficient. The high-purity amorphous silica powder has an average particle diameter of 1.2 to 6 μm, particularly 1.5 to 3.5 μm, and a content of particles having a particle diameter of 2 μm or more is 15% by weight. %, Preferably in the range of 15 to 30% by weight. The use of amorphous silica powder having such a particle size distribution, the amorphous phase content ratio was used as a predetermined ratio and in porcelain of each crystal phase in the porcelain from only SiO _2, or SiO ₂ and B ₂ O ₃ This is the most preferable in that it is composed of only these.

In the present invention, the mixing ratio of the crystallized glass powder, the ZnO powder, and the amorphous silica powder is such that the amount of the crystallized glass powder in the mixed powder is 65 to 85% by weight, and the amount of the ZnO powder is 5%. -20% by weight, especially 7-15% by weight, and the amount of amorphous silica powder is set to 3-20% by weight, especially 10-20% by weight. The amount of each crystal phase to be precipitated can be set in the range described above.

Further, in the present invention, when the above-mentioned Co-containing porcelain is manufactured, CoO is further added to the above mixed powder.
Powder or Co ₃ O ₄ powder, from 0.05 to 0.05 in terms of CoO
It is added in a proportion of 5% by weight, especially 0.1 to 2.0% by weight. In this case, in order to uniformly disperse Co in the porcelain, Co ₃ O having a specific surface area (BET) of 10 m ² / g or more is used.
Preferably, _four powders are used. In addition, Co ₃ O
₄ releases oxygen by heating and is converted to CoO,
The released oxygen has the effect of promoting binder removal. Accordingly, Co ₃ O is used in that the binder is effectively removed and the amount of residual carbon in the porcelain is reduced.
It is advantageous to use ₄ powders.

Preparation of Molding Slurry and Molding To the mixed powder obtained above, an organic binder such as polyvinyl alcohol and methacrylate resin is added, and if necessary, a plasticizer such as dibutyl phthalate and dioctyl phthalate, and toluene, An appropriate amount of an organic solvent such as ethyl acetate or isopropanol is mixed to prepare a molding slurry.
Using the above molding slurry, a molding method known per se, for example, a doctor blade method, a calendar roll method,
A compact having a shape suitable for the intended use is prepared by a rolling method or a press molding method, and the binder is removed and baked.

In this case, when producing a high-frequency wiring board, a sheet-like molded product (green sheet) having a predetermined thickness is used.
Then, if necessary, through holes are formed in the green sheet, and the through holes are filled with a metal paste containing at least one of copper, silver, and gold. Also,
On the surface of the green sheet, a high-frequency line pattern capable of transmitting a high-frequency signal using the metal paste is printed by a known printing method such as a screen printing method or a gravure printing method so that the thickness of the wiring layer is 5 to 30 μm. , Apply.
Next, the plurality of green sheets are laminated and pressed by aligning the through holes and the line patterns, and the laminated sheet is subjected to binder removal and firing.

Debinding The binder is removed by heat treatment in a steam-containing atmosphere. When heat treatment is performed in such an atmosphere, carbon remaining after the binder is thermally decomposed reacts with water vapor, so that the binder can be effectively removed. Further, as described above, when Co ₃ O ₄ powder is used, debinding is promoted by oxygen released when Co ₃ O ₄ is converted to CoO.
When the Cu wiring layer is formed by simultaneous firing, Cu
The binder is removed in a non-oxidizing atmosphere containing water vapor (for example, a nitrogen atmosphere) to prevent oxidation of the binder.

It is preferable that the above-described debinding is performed so that the amount of residual carbon is 100 ppm or less, particularly 80 ppm or less. If the amount of residual carbon is large, not only may the density of the porcelain decrease, the dielectric loss increases, the insulation may decrease, but also by firing,
There is a possibility that a protruding defect is generated on the surface of the porcelain. In particular,
When a wiring board having an insulating substrate made of the above-described porcelain is manufactured by simultaneous firing with the wiring layer of the low-resistance conductor, if a protruding defect occurs on the surface of the wiring layer of the low-resistance conductor, the wiring board may be damaged. The reliability of the connection between the device and the external element is significantly impaired. In the present invention, these disadvantages can be effectively avoided by adjusting the amount of residual carbon to the above range.

In the present invention, in order to suppress the amount of residual carbon within the above range, it is desirable to remove the binder by a two-stage heat treatment. For example, 650-710 ° C and 7
It is preferable to remove the binder by performing heat treatment in two stages at 20 to 770 ° C, and particularly to perform heat treatment at 650 to 710 ° C for 1 hour or more, and then perform heat treatment at 720 to 770 ° C for 1 hour or more. Is most suitable for suppressing the amount of residual carbon within the above range.

The calcination calcination carried out after the debinding is carried out in a non-oxidizing atmosphere such as nitrogen atmosphere or in an oxidizing atmosphere such as air, when formed by co-firing the Cu wiring layer, Cu
Is fired in a non-oxidizing atmosphere in order to prevent oxidation. The firing in the above atmosphere is 800 to 1000
C., especially at 875-1000 ° C., for at least 0.5 hour, thereby densifying and containing the above-described various crystalline and amorphous phases of the high-frequency porcelain of the present invention, or such a high-frequency porcelain A high-frequency wiring board using porcelain as an insulating substrate can be obtained. In addition, a wiring board having a Cu wiring layer (a Cu paste is used as the metal paste)
Then, after firing, electroless Ni-Au plating, electroless Cu
-Au plating is applied to the Cu wiring layer on the substrate surface to form a plating layer. At this time, when the insulating substrate is formed of high-frequency porcelain containing a Co component, Au adhesion to the surface of the insulating substrate is effectively suppressed. If desired, the surface of the wiring board formed as described above may be
A high-frequency element such as i, GaAs, SiGe or the like is mounted, and is connected to a wiring layer provided on a wiring board so that high-frequency signals can be transmitted. For example, a high-frequency element can be directly mounted on the surface of the wiring layer via solder, or the high-frequency element can be connected using wire bonding, a TAB tape, or the like. Further, on the surface of the wiring board on which the high-frequency element is mounted, if necessary, a cap made of the same kind of insulating material as the insulating substrate, another insulating material, or a metal having good heat dissipation properties, such as glass, resin, brazing material, etc. By bonding with an adhesive, the high-frequency element can be hermetically sealed, and thus a high-frequency semiconductor module can be manufactured.

(Structure of High Frequency Wiring Board) The high frequency wiring board provided with the insulating substrate formed by the above-described high frequency porcelain can have various structures. In the schematic cross-sectional perspective view of FIG. 2 showing one example, an insulating substrate 1 having a predetermined thickness A is composed of three layers of insulating layers 1a, 1b, and 1c. Further, a pair of conductor layers 2 and 3 are formed so as to sandwich the insulating substrate 1. Insulating substrate 1
Inside, a large number of via holes 4 extending in the thickness direction of the insulating substrate 1 are provided, and the conductor layers 2 and 3 are electrically connected to each other by these via holes 4.

As is apparent from FIG. 2, the via hole 4
Two rows of via holes 4 are arranged at a predetermined interval B, and the via holes 4 of each row are arranged at a predetermined interval C, and each row of the via holes 4 extends in the signal transmission direction (line forming direction). That is, the space surrounded by the via holes 4 and the conductor layers 2 and 3 becomes the dielectric waveguide line 6. There is no particular limitation on the thickness A of the insulating substrate 1, but when a single-mode high-frequency signal is used, the size is preferably about B / 2 or about 2B based on the interval B between the rows of the via holes 4. .

The distance C between the via holes 4 forming each column
Are set at an interval smaller than the signal wavelength λc (cutoff wavelength) to be transmitted, thereby forming an electrical wall, whereby the signal is confined between the two rows of via holes 4. Since a TEM wave can propagate between the pair of conductor layers 2 and 3 placed in parallel, for example, if the distance C between the via holes 4 is equal to or longer than the cutoff wavelength λc, even if an electromagnetic wave is supplied to the line 6, the TEM wave propagates. If the distance C between the via holes is smaller than the cutoff wavelength λc, the electromagnetic wave is shielded in a direction perpendicular to the line 6, and the electromagnetic wave in the dielectric waveguide line 6 surrounded by the conductor layers 2 and 3 and the via hole 4. Propagates while reflecting light.

In FIG. 2, the insulating layers 1a, 1a
A conductor layer 5 is formed in the via hole formation row region between b and 1c, and the conductor layer 5 enhances the electromagnetic wave shielding effect. Further, in FIG. 2, a slot 7 is formed in the conductor layer 2 formed on one surface of the dielectric waveguide line 6, and a high-frequency signal transmitted through the dielectric waveguide line 6 is a slot. Radiated from 7. Therefore,
This dielectric waveguide line 6 functions as a waveguide antenna.

Further, as shown in another example of FIG. 3, another dielectric waveguide line 8 may be connected so as to surround a slot (not shown) formed on the surface of the conductor layer 2. it can. In addition, in the examples of FIGS. 2 and 3, by providing a via hole conductor (not shown) penetrating the slot, the slot 7 can be extended outside the dielectric waveguide line 6 to extract a high-frequency signal. Further, it is also possible to mount a high-frequency element (not shown) on the front surface of the insulating substrate 1, particularly on the back surface of the slot 7 forming surface.

As described above, the high frequency porcelain of the present invention has a dielectric loss at 15 GHz of 10 × 10 ⁻⁴ or less,
The dielectric loss at 0 GHz is 15 × 10 ⁻⁴ or less, and the dielectric loss in a high frequency band is very small. Therefore, in the above-described wiring board, by forming the insulating substrate 1 from the above-described high-frequency ceramic, the high-frequency signal can be transmitted through the dielectric waveguide line 6 without being attenuated. The dielectric constant of the high frequency porcelain of the present invention is 6 or less, and in this respect, the wiring board including the insulating substrate 1 formed of such high frequency porcelain has excellent transmission characteristics of high frequency signals. I have. The coefficient of thermal expansion of the high frequency porcelain of the present invention from room temperature to 400 ° C. is 5 to 8 ppm / ° C.
Which is close to the coefficient of thermal expansion of the semiconductor element. Therefore, the insulating substrate 1 formed by such a high-frequency porcelain
Is extremely useful for applications in which high-frequency elements are mounted.

FIG. 4 is a schematic sectional side view of a high-frequency package which is one of preferred examples of the high-frequency wiring board of the present invention. In FIG. 4, this package, which is generally designated by 20, includes an insulating substrate 21 made of the high-frequency ceramic of the present invention, and a cavity 23 closed by a lid 22 is formed on the upper surface of the insulating substrate 21. ing. In this cavity 23, a high-frequency element 24 such as Si, SiGe, or GaAs is mounted. The lid 22 is desirably made of a material that can prevent leakage of electromagnetic waves between the high-frequency element 24 and the outside. On the surface of the insulating substrate 21, a wiring layer 25 electrically connected to the high-frequency element 24 is formed.

In the present invention, 1 GHz or more, especially 15 GHz
GHz or more, furthermore 50 GHz or more, furthermore 70 GH
In order to transmit a high frequency signal of z or more by the wiring layer 25, the wiring layer 25 may be formed of at least one of a strip line, a microstrip line, a coplanar line, and a dielectric waveguide line. desirable. Thereby, transmission loss of a high-frequency signal can be reduced. Further, in order to reduce transmission loss of a high-frequency signal, the wiring layer 25 contains any one of low-resistance metals such as copper, silver and gold, and it is particularly preferable that these metals are the main components.

In the package 20 of FIG. 4, the wiring layer 25 and the ground layer 26 are connected to the microstrip line 2.
7 are formed. A wiring layer 28 connected to an external circuit board is formed on the back surface of the insulating substrate 21, and forms a microstrip line 29 together with the ground layer 26. The wiring layer 25 and the wiring layer 28 are electromagnetically coupled by forming their ends through slot holes 30 formed in the ground layer 26 so that the ends of the wiring layers face each other, thereby forming a microstrip line. Signals with low loss are transmitted between the microstrip line 27 and the microstrip line 29.

In the present invention, the structure of the wiring layer is not limited to the above-described electromagnetic coupling structure. For example, the dielectric waveguide as described above may be provided at the end of the microstrip line 27 in FIG. It is also possible to stack and arrange the lines, and connect the dielectric waveguide line and the microstrip line 27 by a via-hole conductor passing through a slot 30 provided in a part of the earth layer 26. In the package 20 of FIG. 4, the high-frequency element 24 is hermetically sealed by the insulating substrate 21 and the lid 22. However, the present invention is not limited to this. The element 24 may be sealed with a resin mold or the like.

[0043]

EXPERIMENTAL EXAMPLE 1 Four kinds of crystallized glasses having the following compositions were prepared. Glass A: 44% by weight of SiO ₂ -29% by weight of Al ₂ O ₃ -11% by weight of MgO-7% by weight of ZnO-9% by weight of B ₂ O ₃ Glass B: 50% by weight of SiO ₂ -15% by weight of Al ₂ O ₃ -MgO 9 wt% -ZnO18 wt% _-B 2 _{O 3} 8 wt% glass _C: SiO 2 10.4 _wt% -Al ₂ O 3 2.5 wt% _-B 2 _O 3 45.3 wt% -ZnO35.2 wt% -Na ₂ O6.6 wt% glass _D: SiO 2 14.2 _wt% -Al ₂ O 3 24.5 wt% _-B 2 _O 3 22.6 wt% -CaO14.2 wt% _-Li 2 O12.8 _weight% -Na 2 O11.7% by weight

An average particle diameter of 1 μm was added to the above crystallized glass powder.
m ZnO powder and amorphous silica powder having the particle size distribution shown in Table 1 were mixed so that the porcelain after firing had the composition shown in Table 1. The particle size of each raw material was measured by determining the area ratio from a SEM photograph of the raw material powder using Luzex analysis. The amorphous silica raw material powder was subjected to ICP analysis, infrared absorption spectrum analysis, and Raman spectroscopy to measure the amount of impurity metals, and the results are shown in Table 1.

An organic binder, a plasticizer, and toluene were added to the obtained mixed powder to prepare a slurry.
m green sheets were produced. Then, 10 to 15 green sheets are laminated, and a temperature of 50 ° C. and a pressure of 10MP
A thermocompression bonding was performed by applying the pressure of a.

The obtained laminate is placed in a steam-containing / nitrogen atmosphere (dew point: 60 ° C.) at 700 ° C. for 1 hour, and further at 750 ° C.
For 1 hour, and then fired in dry nitrogen under the conditions shown in Table 1 to obtain a high frequency porcelain.

For some of the samples, instead of ZnO and amorphous silica, quartz powder of crystalline SiO ₂ , Al ₂ O ₃ powder, Ca ₂
Porcelain was similarly prepared using the O powder (Sample Nos. 9 to 9).
11, 18). Also, heat treatment for debinding
Sample No. 1 was performed in one step at 750 ° C. for 1 hour. Porcelain was obtained in the same manner as in Sample No. 3 (Sample No. 25). The obtained porcelain was evaluated for permittivity, dielectric loss, transverse rupture strength, and coefficient of thermal expansion by the following methods. Further, component analysis in the porcelain and evaluation of signal transmission performance were performed, and the results are shown in Table 2. .

Dielectric constant and dielectric loss: A porcelain sample was cut into a disk having a predetermined size, and 15 GHz or 60 GHz.
At z, the measurement was performed by a dielectric cylinder resonator method using a network analyzer and a synthesized sweeper. At the time of measurement, the dielectric resonator is excited by an NRD guide (non-radiative dielectric line), and TE ₀₁₁ or T
The dielectric constant and the dielectric loss were calculated from the resonance characteristics of the _E021 mode. When measuring the dielectric loss at 15 GHz, the disk shape of the sample is 10 mm in diameter and 5 mm in thickness, and when measuring the dielectric loss at 60 GHz,
The disk shape of the sample is 2-7 mm in diameter and 2.0-2.
The size was 5 mm.

Flexural strength: A sample was 4 mm wide × 3 mm thick ×
The sheet was cut into a shape having a length of 70 mm, and the bending strength was measured by a three-point bending test based on the provisions of JISC-2141. Thermal expansion coefficient: A thermal expansion curve was calculated from room temperature to 400 ° C. to calculate a thermal expansion coefficient.

Component analysis: The crystalline phase and the amorphous phase in the porcelain were identified from the X-ray diffraction chart and quantified by the Rietveld method. Furthermore, EDX (Energy
Dispersive X-ray Spectroscopy), EELS (Electr
On Energy Loss Spectroscopy) analysis, the ratio of each element in the amorphous phase was measured, and the element whose ratio was 50 ppm or more was confirmed. Further, the amount of residual carbon in the porcelain was measured by an infrared absorption method.

Transmission performance: Regarding the transmission performance,
A strip line and the strip are placed on an insulating substrate made of porcelain.
The end of the line consists of a converted coplanar line
High-frequency signal transmission line is formed by simultaneous firing with insulating substrate
Done. The strip line is formed on the surface of the insulating substrate.
1cm, 2cm, 3cm in length, 260μm in width,
A center conductor (Cu) with a thickness of 10 μm and the entire inside of the insulating substrate
Ground layer (center conductor and ground layer)
(Interval with 150 μm). This
From one end of the high-frequency signal transmission line thus formed.
GHz signal, and the other end
The signal transmission performance S ₂₁Measure
Was.

[0052]

[Table 1]

[0053]

[Table 2]

As is clear from Tables 1 and 2, SiO 2₂,
Al₂O₃, MgO, ZnO and B ₂O₃Containing glass
Sample No. whose amount exceeds 85% by weight. 1 and 14, Zn
O and Al₂O₃30% by weight of the crystal phase containing
Less and also SiO₂Of crystalline phase containing MgO and MgO
The ratio is less than 5% by weight and the dielectric loss is high.
And the porcelain strength was low. Conversely, the amount of glass
Is less than 65% by weight. In 8, the porcelain is 100
Densification could not be performed at a temperature of 0 ° C. or less. Ma
Instead of ZnO powder and amorphous silica powder,
Sample No. to which another ceramic filler powder was added. 9 ~
11 and 18, other than Si or B in the amorphous phase of the porcelain
Other metal components remained, and the dielectric loss of the porcelain increased.

Further, in the amorphous silica raw material, A
Sample No. 1 containing a total of more than 500 ppm of impurity metals of l, Fe and Sb. In 12, 13, 19, and 20, crystallization of amorphous silica was promoted, the amount of quartz deposited in the porcelain exceeded 6% by weight, and the dielectric loss at 60 GHz (high frequency band) tended to increase. . Also, S
Sample Nos. using glasses C and D not containing all of iO ₂ , Al ₂ O ₃ , MgO, ZnO and B ₂ O ₃ . 21
２４24 had a high dielectric loss. On the contrary,
Sample No. 1 was obtained by mixing glasses A and B containing all of SiO ₂ , Al ₂ O ₃ , MgO, ZnO and B ₂ O ₃ and mixing a specific amount of ZnO powder and high-purity amorphous silica powder. Each of the porcelains 2 to 7 and 15 to 17 has a dielectric constant of 5.7 or less and a dielectric loss of 10 × 1 at 15 GHz.
0 ⁻⁴ or less, dielectric loss at 60 GHz is 15 × 10 ⁻⁴
Below, strength 200MPa or more, thermal expansion coefficient 5-6ppm
/ ° C or less. Further, in Sample No. in which the binder was removed by a one-step heat treatment. In 25,
The residual carbon amount was more than 100 ppm, and the dielectric loss increased.

Experimental Example 2: In this experimental example, evaluation was performed on a porcelain containing a Co component. First, glasses A and B used in Experimental Example 1 were used as crystallized glass. This glass powder was mixed with amorphous silica powder and cobalt oxide (Co ₃ O ₄ ) powder at the ratios shown in Table 3,
A mixed powder was prepared. (In Table 3, the amount of cobalt oxide was shown as a value in terms of CoO.) As the amorphous silica powder, the sample No. of Experimental Example 1 was used. The one used in 4 was used. The following three types of a, b, and c were used as the cobalt oxide powder. Cobalt oxide powder (a): BET specific surface area 40 g / m
² cobalt oxide powder (b): BET specific surface area of 10 g / m
² cobalt oxide powder (c): BET specific surface area of 1 g / m
²

Based on 100% by weight of the above mixed powder, 12% by weight of solid content of isobutyl methacrylate resin (organic binder), 6% by weight of dibutyl phthalate (plasticizer), and a mixed solvent of toluene / ethyl acetate Was added and mixed by a ball mill for 40 hours to prepare a slurry.
Using the obtained slurry, a green sheet having a thickness of 0.25 mm was formed by a doctor blade method.
The eight green sheets obtained as described above were laminated under pressure in the same manner as in Experimental Example 1, and were cut into a square shape with one side of 60 mm to produce a molded body for an insulating substrate. Further, a glass paste, a ceramic powder, an organic binder, a plasticizer and a solvent are added to the Cu powder to prepare a Cu paste.
The u paste was printed on the surface of the green sheet obtained above in a square shape having a side of 12 mm. A green sheet (C
u sheet) and two green sheets on which the Cu paste is not printed are overlapped so that the Cu sheet is the uppermost layer, and pressure-laminated in the same manner as in Experimental Example 1. It was cut into a square shape to produce a molded product for a wiring board.

The molded body for an insulating substrate and the molded body for a wiring substrate obtained above were subjected to a two-stage heat treatment to remove the binder in the same manner as in Experimental Example 1, and then fired at the temperature shown in Table 3. Thus, a wiring board having an insulating substrate and a Cu conductor layer was obtained. About this insulating substrate, as in Experimental Example 1, 6
The dielectric constant and the dielectric loss (tan δ) at 0 GHz were measured. Further, the number of protrusion-like defects on the insulating substrate was visually measured, and the bending strength and the amount of residual carbon were measured in the same manner as in Experimental Example 1. Further, the lightness in the L * a * b color system was measured. L * and chroma C * were measured. For the wiring substrate, after etching the surface of the Cu conductor layer, an electroless Ni plating layer is formed with a thickness of 3 μm, and an electroless Au plating layer is formed with a thickness of 1 μm. The surface was observed with a stereo microscope of 40 times, and the presence or absence of discoloration due to Au adhesion was observed. Table 4 shows the results.

[0059]

[Table 3]

[0060]

[Table 4]

From the results shown in Tables 3 and 4, the porcelain containing less than 0.05% by weight of the Co component (samples Nos. 1, 2 and 2).
In 11), discoloration due to Au adhesion occurred, but Co
In other porcelain containing more than 0.05% by weight of components,
It can be seen that discoloration due to Au adhesion is effectively prevented. In the case of porcelain having a Co content of more than 5% by weight (samples Nos. 10 and 15), the dielectric loss increased. Further, in the porcelain using the cobalt oxide powder having a specific surface area smaller than 10 m ² / g (Sample No. 19), the Co component was not uniformly dispersed, and as a result, a large number of projection defects were generated.

[0062]

According to the present invention, impurities in terms of metal are
Amorphous silica powder with a content of 500 ppm or less
Use this high purity amorphous silica powder and the specified composition
Containing a predetermined amount of crystallized glass and ZnO powder
Preparation, molding, and de-built of molding slurry using powder
Baking at a temperature of 1000 ° C or less
As a result, SiO₂, Al₂O₃, M
gO, ZnO and B₂O ₃And, as a crystal phase, Zn
O and Al₂O₃Crystalline phase containing and SiO₂And MgO
Containing a certain proportion of crystalline phase₂Or SiO₂
And B₂O₃And an amorphous phase consisting of
O₂High frequency with crystal phase content suppressed to 6% by weight or less
Porcelain can be obtained. This porcelain is
The crystallization of Rufus silica is effectively suppressed,₂Conclusion
Whether the crystal phase content is controlled to 6% by weight or less
That the dielectric loss at 60 GHz is 15 × 10^-4Below
Very similar to high frequency devices such as GaAs chips
Thermal expansion coefficient. Therefore, for such high frequency
Porcelain is insulated on the wiring board to which high-frequency signals are applied.
When used as a substrate, it can be used simultaneously with gold, silver, and copper low-resistance conductors.
Substrate that can be manufactured by firing and that can be obtained
Is not only high in porcelain strength but also in the high frequency range
Low dielectric loss, capable of transmitting high-frequency signals without loss
In addition, thermal stress can be reduced when mounting high frequency devices.
Generation can be effectively prevented and a reliable
Structure can be secured. In addition, the Co component is
The high frequency porcelain according to the present invention includes a Cu wiring layer.
It is extremely useful for wiring board applications.
Insulation when forming a plating layer such as i-Au or Cu-Au
Au on the substrate surface can be effectively prevented, and Au
Effectively avoids discoloration due to adhesion and deterioration of insulation between wiring layers
can do.

[Brief description of the drawings]

FIG. 1 is a schematic diagram for explaining the structure of a high-frequency porcelain according to the present invention.

FIG. 2 is a schematic cross-sectional perspective view of a high-frequency wiring board including a dielectric antenna, which is an example of a high-frequency wiring board using the high-frequency ceramic of the present invention.

FIG. 3 is a schematic cross-sectional perspective view of a high-frequency wiring board including a dielectric antenna having a structure different from that of FIG. 2 as an example of a high-frequency wiring board using the high-frequency ceramic of the present invention.

FIG. 4 is a schematic cross-sectional side view of a semiconductor element storage package as another example of a high-frequency wiring board using the high-frequency ceramic of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01Q 13/10 H05K 3/46 H H05K 1/03 610 T 3/46 Z C04B 35/18 Z H01L 23 / 14 C (72) Inventor Satoshi Hamano 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Prefecture Inside the Kyocera Research Institute (72) Inventor Kazun 1-4-4 Yamashita-cho, Kokubu-shi, Kagoshima Inside the Kyocera Research Institute (72) Inventor Katsuhiko Onizuka 1-4, Yamashita-cho, Kokubu-shi, Kagoshima F-term in Kyocera Research Institute (reference) 4G030 AA07 AA28 AA32 AA35 AA36 AA37 AA60 BA09 CA01 GA11 GA14 GA15 GA17 GA20 GA24 5E346 AA12 AA13 AA15 BB02 BB03 BB04 BB07 BB11 CC18 CC32 CC38 CC39 DD02 DD34 EE24 EE27 FF01 GG03 HH06 5J006 HC07 5J014 HA00 5J045 AB06 DA04 EA03 LA01

Claims (16)

[Claims] 1. A composition comprising SiO ₂ , Al
₂ O _3, MgO, in porcelain containing ZnO and _B 2 _{O 3,} a crystal phase containing ZnO and _Al 2 _{O 3} 30 to 50 wt%,
The crystalline phase containing SiO ₂ and MgO 5 to 15 wt%, substantially, an amorphous phase of SiO ₂ or SiO _{2, B} 2 _{O 3} Metropolitan containing 40 to 60 wt%, and the SiO ₂ crystal phase A porcelain having excellent high frequency characteristics, wherein the content is suppressed to 6% by weight or less and the dielectric loss at 60 GHz is 15 × 10 ⁻⁴ or less. 2. The B ₂ O ₃ content of the amorphous phase is 100.
The porcelain according to claim 1, wherein the porcelain is at most ppm. 3. The porcelain according to claim 1, wherein the content of the willemite crystal phase containing SiO ₂ and ZnO is suppressed to 6% by weight or less. 4. The porcelain according to claim 1, wherein the porcelain has a carbon content of 100 ppm or less. 5. The porcelain according to claim 1, wherein Co is contained in an amount of 0.05 to 5% by weight in terms of CoO. 6. The Co comprises at least ZnO and Al
The porcelain according to claim 5, wherein the porcelain is contained in a crystalline phase containing ₂ O ₃ and an amorphous phase. 7. The porcelain according to claim 5, wherein the lightness L * in the L * a * b color system is at a color position where the lightness L * is smaller than 80 and the saturation C * is larger than 20. 8. SiO ₂ , Al ₂ O ₃ , MgO, ZnO
And crystallized glass 65-85 wt% containing _B 2 _{O 3}
And a raw material mixture of 5 to 20% by weight of ZnO powder and 1 to 20% by weight of an amorphous silica powder having an impurity content of 500 ppm or less in terms of metal, and an organic binder is added to the mixture to form a slurry. The slurry is prepared, and the slurry is formed.
A method for producing porcelain excellent in high frequency characteristics, characterized by firing at 1000 ° C. 9. The amorphous silica powder according to claim 1, wherein
The method according to claim 8, wherein the content of particles having an average particle size of from 6 to 6 µm and having a particle size of 2 µm or more is 15% by weight or less. 10. The method according to claim 8, wherein the binder removal treatment is performed by a two-stage heat treatment at 650 to 710 ° C. and 720 to 770 ° C. 11. The method according to claim 10, wherein the heat treatment at 650 to 710 ° C. is performed for one hour or more, and the heat treatment at 720 to 770 ° C. is performed for one hour or more. 12. The raw material mixture has a specific surface area of 10 m.
²/ G or more of Co₃O ₄The powder was converted to 0.05 in terms of CoO.
The production method according to claim 8, wherein the content is from 5 to 5% by weight. 13. A high-frequency device comprising: an insulating substrate formed from the porcelain according to claim 1; and a wiring layer formed on the surface and / or inside of the insulating substrate and capable of transmitting a high-frequency signal having a frequency of 1 GHz or more. Wiring board. 14. The wiring layer is formed of at least one of a strip line, a microstrip line, a coplanar line, and a dielectric waveguide line, and is formed by co-firing with the insulating substrate. Item 1
4. The high-frequency wiring board according to 3. 15. The high-frequency wiring board according to claim 14, wherein the wiring layer contains at least one selected from copper, silver, and gold. 16. The high frequency according to claim 13, wherein the wiring layer formed on the surface of the insulating substrate contains copper, and an Au plating layer having a thickness of 1 μm or more is formed on the copper-containing wiring layer. Wiring board.