JP2001261432A - Porcelain composition for high-frequency and porcelain for high-frequency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtains porcelain which is used as an insulating layer of a wiring board for high-frequency and capable of being fired at 800-1,000 deg.C and showing reduced dielectric loss in a high-frequency region, also to provide a production process of the porcelain and further to provide a porcelain composition for producing the porcelain. SOLUTION: The production process of this porcelain comprises: mixing 40-99 wt.% of glass which contains SiO2, Al2O3, MgO and CaO and from which a diopside-type crystalline phase (DI) can be crystallized out, with 1-60 wt.% of at least γ-alumina (Al2O3) to obtain a mixture; forming the mixture into a green body; and thereafter firing the green body at 800-1,000 deg.C to produce the objective porcelain which contains the diopside-type crystalline phase (DI) and at least a γ-alumina crystalline phase (Al) and also has a <=30×10-4 dielectric loss in the region of 60-77 GHz, a dielectric constant of <=10, >=250 MPa porcelain strength and a >=5×10-6/ deg.C thermal expansion coefficient in the range of room temperature to 400 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is applied to a package for housing a semiconductor element, a multilayer wiring board, and the like, and in particular, a high-frequency ceramic used as an insulating substrate in a wiring board used in a high-frequency band such as a microwave or a millimeter wave. The present invention relates to a composition, a high frequency porcelain, a method of manufacturing the high frequency porcelain, and a wiring substrate using the high frequency porcelain as an insulating substrate.

[0002]

2. Description of the Related Art Conventionally, as a ceramic multilayer wiring board,
An insulating substrate made of an alumina-based sintered body having a wiring layer made of a refractory metal such as tungsten or molybdenum formed on the surface or inside thereof is most widely used.

Further, recently, with the era of advanced information, the frequency band to be used is shifting to higher and higher frequencies. In such a high-frequency wiring board that requires transmission of a high-frequency signal, in order to transmit a high-frequency signal without loss, the resistance of the conductor forming the wiring layer is small, and the dielectric of the insulating substrate in the high-frequency region is low. Low loss is required.

However, conventional tungsten (W),
Refractory metals such as molybdenum (Mo) have high conductor resistance, have low signal propagation speeds, and have difficulty in signal propagation in the high-frequency region of 1 GHz or higher. It is necessary to use low resistance metals such as silver and gold.

A wiring layer made of such a low-resistance metal is
Since the melting point is low and it is impossible to co-fire with alumina, recently, a wiring board using glass or a composite material of glass and ceramic, that is, a so-called glass ceramic as an insulating substrate is being developed.
For example, as disclosed in Japanese Patent Application Laid-Open No. 60-240135, a multilayer wiring board is proposed 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. I have.

Accordingly, for example, Japanese Patent Application Laid-Open No. 10-12043 discloses
No. 6, JP-A-11-49531, 0 to 30% by weight of ceramic powder such as alumina or mullite is added and mixed with 70 to 100% by weight of glass powder capable of precipitating a diopside crystal phase. A sintered porcelain has been proposed and discloses that the dielectric loss at a frequency of 2 GHz can be reduced to 3 to 7 × 10 ⁻⁴ .

[0007]

SUMMARY OF THE INVENTION However, MgC
The diopside type crystal phase of aSi ₂ O ₆ and Ca (Mg, Al) (Si, Al) ₂ O ₆ is a crystal having a low dielectric loss in a high frequency band, but is easily crystallized on the surface, and the glass inside the glass raw material particles is glassy. It is known that it is difficult to increase the ratio of the diopside crystal phase in the porcelain due to the remaining, and the dielectric loss at 2 GHz can be 3 to 7 × 10 ⁻⁴ , but the millimeter wave The dielectric loss in the band is high. In particular, when SrO is contained in a glass capable of precipitating a diopside type crystal phase, the porcelain can be densified by firing at a low temperature, but the dio in the porcelain can be reduced. As a result, the crystallinity of the puside crystal phase decreases and the proportion of the glass phase having a large dielectric loss in the porcelain increases, resulting in a problem that the dielectric loss decreases.

Accordingly, an object of the present invention is to provide a porcelain capable of further reducing dielectric loss in a high-frequency region, a method for producing the same, a high-frequency porcelain composition capable of producing the same, and a wiring board using the same. I do.

[0009]

Means for Solving the Problems As a result of diligent study of the above-mentioned problems, the present inventors have found that SiO ₂ , Al ₂ O ₃ , MgO, Sr
For a glass containing O and CaO and capable of precipitating a diopside crystal phase, at least γ-
By blending Al ₂ O ₃ at a predetermined ratio, the precipitation ratio of the diopside crystal phase in the porcelain can be increased, and the residual amount of glass that causes an increase in dielectric loss can be reduced. As a result, it was found that the dielectric loss in the high frequency region can be significantly reduced.

That is, the high frequency porcelain composition of the present invention has
Glass 40 containing iO ₂ , Al ₂ O ₃ , MgO, SrO and CaO and capable of precipitating a diopside crystal phase
99% by weight and at least γ-Al ₂ O ₃
Is contained in a ratio of 1 to 60% by weight.

Here, the glass is made of SiO ₂ 30 to 5
5% by weight, 4 to 15% by weight of Al ₂ O ₃ ,
30% by weight, 5-20% by weight of CaO, 10% by weight of SrO10
It is desirably 25% by weight.

Further, the high frequency porcelain of the present invention contains at least a diopside type crystal phase containing Mg, Ca, Si, Sr, and Al, and at least a γ-Al ₂ O ₃ crystal phase, and Dielectric loss at 77 GHz is 30 × 10 ^-4
It is characterized by the following.

It is desirable that the glass phase contains 30% by weight or less of the glass phase, and that the glass phase contains at least 50% by weight or more of Si in terms of oxide (SiO ₂ ).

The thermal expansion coefficient from room temperature to 400 ° C. is 5 × 10 ⁻⁶ / ° C. or more, the dielectric constant is 10 or less, the porcelain strength is 250 MPa or more, and the thermal conductivity is 3 W / m · K.
It is desirable that this is the case.

The method for producing a high-frequency porcelain according to the present invention is characterized in that it comprises SiO ₂ , Al ₂ O ₃ , MgO, SrO and CaO.
Containing a diopside crystal phase
0-99% by weight and at least γ-Al as a filler
After forming a mixture comprising 1 to 60% by weight of ₂ O ₃ , 80%
Firing at a temperature of 0 to 1000 ° C. to at least Mg, C
The present invention is characterized by producing a porcelain containing a diopside type crystal phase containing a, Si, Sr, and Al and at least a γ-Al ₂ O ₃ crystal phase.

Further, the wiring board of the present invention is provided on the surface and / or inside of the insulating substrate made of the high frequency porcelain.
Particularly, a metallized wiring layer mainly composed of Cu or Ag is provided.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The high frequency porcelain composition of the present invention comprises:
Glass containing SiO ₂ , Al ₂ O ₃ , MgO, SrO and CaO and capable of precipitating a diopside crystal phase is 40
And at least γ-Al ₂ as a filler.
O ₃ and those containing at a ratio of 1 to 60 wt%.

The reason for limiting each component composition to the above range is as follows.
If the amount of the glass is less than 40% by weight, it is difficult to densify the porcelain by firing at a temperature of 1000 ° C. or less. If the amount is more than 99% by weight, the crystallinity in the porcelain decreases, and This is because the dielectric loss increases. A particularly desirable range of glass is 65-97% by weight, especially 80-97% by weight.
95% by weight.

Here, the glass preferably has a softening point of 500 to 800 ° C., and the composition of the glass is 30 to 55% by weight of SiO ₂ , 4 to 15% by weight of Al ₂ O ₃ , and 14 to 15% by weight of MgO. 30% by weight, 5-20% by weight of CaO,
Desirably, the ratio of SrO is 10 to 25% by weight.

Among the above glass components, SrO has a function of accelerating the densification of porcelain, and can reduce the amount of expensive glass by increasing the amount of filler that can be contained in the porcelain. In addition to improving the thermal expansion coefficient of the porcelain, adjusting the dielectric constant of the porcelain, improving the strength of the porcelain, improving the thermal conductivity, and the like.

In the glass capable of precipitating the diopside type crystal phase, only the surface of the glass material particles is crystallized in the sintered body, and a glass phase having a large dielectric loss tends to remain in the center. According to the present invention, by mixing at least γ-Al ₂ O ₃ as a filler at a predetermined ratio with respect to the glass, it is possible to increase the precipitation ratio of a diopside crystal phase in the porcelain, 1 GHz or more, further 20 GHz or more, furthermore 50 GHz or more,
Furthermore, dielectric loss in a high frequency region of 70 GHz or more can be significantly reduced.

Further, in order to increase the precipitation ratio of the diopside type crystal phase from the glass, it is desirable that the total amount of CaO and MgO in the glass is 35 to 50% by weight.

On the other hand, it is important that the content of γ-Al ₂ O ₃ incorporated as a filler in the composition is 1 to 60% by weight. That is, when the content of γ-Al ₂ O ₃ is less than 1% by weight, the crystallization ratio in the porcelain decreases, the proportion of the glass phase increases, and the dielectric loss of the porcelain increases. If the content of γ-Al ₂ O ₃ exceeds 60% by weight, sintering becomes difficult, and densification cannot be performed at a firing temperature of 1000 ° C. or lower. γ-Al ₂ O ₃
Is preferably from 3 to 35% by weight in terms of low-temperature calcination,
In particular, it is 5 to 20% by weight.

In the above composition, as a filler,
γ-Al_TwoO_ThreeOther than α-Al_TwoO_Three(Corundum), β-
Al_TwoO_Three, MgAl_TwoO_Four, ZnAl_TwoO_Four, 3Al_TwoO_Three・
2SiO_Two, Mg_TwoAl_FourSi_FiveO₁₈, SiO_Two, TiO_Two,
MgTiO_Three, SrTiO_Three, BaTiO_Three, CaTi
O_Three, Zn_TwoTiO_Four, CuO, Cu_TwoO, especially low dielectric loss
In terms of loss, MgAl_TwoO_Four, ZnAl_TwoO_Four, MgTiO
_Three, SrTiO_Three, SiO _TwoEspecially SiO_Two, MgTiO
_ThreeΑ-Al for improving porcelain strength and thermal conductivity_Two
O_Three(Corundum), β-Al_TwoO_ThreeEspecially α-Al_TwoO_Three
Other crystal phases such as
The filler component is γ-Al_TwoO_Three60% by weight or less
It is desirable to be below.

The porcelain composition of the above embodiment has a composition of 800 to 10
By firing in a temperature range of 00 ° C., the relative density can be reduced to 97% or more, particularly to 99% or more.

Further, the high frequency porcelain of the present invention has a diopside type crystal phase containing at least γ-Al ₂ O ₃ (γ-Al) and at least Mg, Ca, Si, Sr and Al as crystal phases. Certain Ca (Mg, Al) (Si, Sr, A
l) ₂ O ₆ (DI).

Further, the porcelain comprises the diopside type crystal phase Ca (Mg, Al) (Si, Al) ₂ O ₆ (DI)
Is desirably high in the rate of precipitation from the glass. In addition, Ca ₂ MgSi ₂ O ₇ (aker
manite), CaMgSiO ₄ (monticel)
lite), Ca ₃ MgSi ₂ O ₈ (merwinit
A similar phase such as e) may be precipitated, and (Ca, Sr) SiO ₃ , SrSiO _3, etc. may be precipitated from SrO.

Further, γ-Al ₂ O ₃ is, for example, spherical,
It is desirable that the particles have a shape of a needle, an irregular shape, or the like and are dispersed in the porcelain, and that α-Al ₂ O _{3 in} which a part of γ-Al ₂ O ₃ is transformed by firing is present. Is also good.

The amorphous glass (G) remains in the porcelain at the grain boundaries of the above-mentioned crystal phase. However, the amorphous glass (G) reduces the dielectric loss, and also has the problem of improving the strength of the porcelain. To reduce the proportion of glass in the porcelain to 30% by weight or less, preferably 1%.
From the viewpoint of reducing the content to 0% by weight or less, particularly 5% by weight or less, and further 2% by weight or less, and reducing the dielectric loss, the content of the Si component in the glass is 50% by weight or more, particularly 60% by weight, in terms of SiO _2. %, More preferably at least 65% by weight.

The porcelain of the above embodiment has a dielectric loss of 30 × 10 ⁻⁴ or less at 60 to 77 GHz, preferably 15 × 1 ^−4.
The dielectric loss is small in a high frequency band of 0 ^-4 or less, particularly 10 × 10 ^-4 or less, and 1 GHz or more, particularly 20 GHz or more, furthermore 50 GHz or more, and even 70 GHz.
This is a porcelain suitable for forming the insulating layer of the high-frequency wiring board described above.

In addition to increasing the crystallinity of the glass in the porcelain, the thermal conductivity of the porcelain can be increased to 3 W / m · K or more by adding a filler component.

Further, the diopside type crystal phase is
Since it has a high thermal expansion characteristic of about 8 to 9 × 10 ⁻⁶ / ° C., a diopside crystal phase is precipitated from glass having the above composition, and at least γ-Al ₂ O ₃ is added in a specific amount, and at least γ is added. by precipitating -Al ₂ O _3, the thermal expansion coefficient of 5 × 10 ^-6 / ℃ or higher, 7 × 10 ^-6 / ℃
In addition to the above, the dielectric constant of the porcelain is as low as 10 or less, especially 8 or less, and the porcelain strength is 250 MPa or more, particularly 30
It can be increased to 0 MPa or more.

That is, the coefficient of thermal expansion of the porcelain is desirably adjusted appropriately so as to approximate the coefficient of thermal expansion of a chip component or a printed circuit board to be mounted.
The coefficient of thermal expansion at 0 ° C. is 5 × 10 ⁻⁶ / ° C. or more, especially 7
× 10 ^-6 / ° C. or higher, it is desirable that further 8 × 10 ^-6 / ℃ above. This is because if the coefficient of thermal expansion of the porcelain is different from that of the mounted chip component or printed circuit board, the temperature of the chip component, printed circuit board and package may be increased by repeated temperature cycles during solder mounting or by stopping the operation of the semiconductor element. This is because stress due to the difference in thermal expansion is generated in the mounting portion, and cracks and the like are generated in the mounting portion, which impairs the reliability of the mounting structure.

More specifically, in order to match with the GaAs-based chip component, the difference in thermal expansion coefficient from the GaAs-based chip component is 2 × 10 ⁻⁶ / ° C. or less. In order to achieve matching, it is desirable that the difference in the coefficient of thermal expansion from the printed circuit board be 2 × 10 ⁻⁶ / ° C. or less. The mounting of the wiring board and the printed board is particularly effective when the printed circuit board is directly mounted via solder, such as a ball grid array (BGA) or a land grid array (LGA).

Further, when the porcelain of the present invention is used as an insulating substrate of a wiring board, the dielectric constant is as low as 10 or less, particularly 8 or less, so that the transmission loss of a high-frequency transmission line or an antenna can be reduced.

Further, by increasing the strength of the porcelain to 250 MPa or more, particularly 300 MPa or more, it is possible to prevent breakage or the like due to stress applied to the porcelain at the time of mounting electronic components such as semiconductor elements or connecting leads to input / output terminals. Can be.

Next, a method for producing a porcelain using the high frequency porcelain composition of the present invention will be described.

First, as starting materials, SiO ₂ , Al ₂ O
₃ , 40 to 99% by weight of crystallized glass powder containing MgO, CaO and SrO and capable of precipitating a diopside crystal phase
And γ-Al ₂ O ₃ are weighed and mixed at a ratio of 1 to 60% by weight.

The γ-Al ₂ O ₃ is spherical,
It is desirable to be in the form of powder such as needles or irregular shapes, and the average particle size is 0.5 μm or more, particularly 1 to 30 μm, and more preferably 1 to 10 μm. For example, unavoidable impurities such as Si, Mg, Ca, and Sr may be contained in an amount of 8% by weight or less, particularly 1% by weight or less.

Then, a molded article having a predetermined shape is prepared using the mixed powder by a known molding method such as a doctor blade method, a calender roll method, a rolling method, or a press molding method. By baking in an oxidizing atmosphere or an inert atmosphere.

The reason for limiting the firing temperature to the above range is that if the firing temperature is lower than 800 ° C., the porcelain cannot be densified, the crystallinity of the glass is low, and the dielectric loss in the high frequency region increases. Conversely, if the temperature exceeds 1000 ° C., simultaneous firing with a low-resistance metal such as Cu or Ag cannot be performed. Note that a part of γ-Al ₂ O ₃ may be transformed into α-Al ₂ O ₃ during firing.

In order to produce a wiring board having a metallized wiring layer, a suitable organic solvent,
A slurry is prepared by mixing with a solvent, and the slurry is formed into a sheet by a well-known doctor blade method, calender roll method, rolling method, or press molding method. Then, after a through-hole is formed in this sheet-like molded body as desired, the through-hole is filled with a metal paste containing at least one of copper, gold, and silver. And
On the surface of the sheet-like molded body, the thickness of the wiring layer is reduced to 5 by a screen printing method, a gravure printing method, a transfer method, or the like using the above-mentioned metal paste or a metal foil made of the above-mentioned metal in a high-frequency line pattern capable of transmitting a high-frequency signal. Print or transfer to a thickness of と 30 μm.

Thereafter, a plurality of sheet-shaped molded bodies are aligned, laminated and pressed, and fired in an atmosphere of nitrogen gas or a mixed gas of nitrogen and oxygen at 800 to 1000 ° C. to produce a high-frequency wiring substrate. Can be.

A chip component such as a semiconductor element is appropriately mounted on the surface of the wiring board, and is connected to the wiring layer so that signals can be transmitted. As a connection method, a connection is made by directly mounting on the wiring layer, or resin, Ag, or the like.
-The chip component is fixed to the surface of the insulating substrate with an adhesive such as epoxy, Ag-glass, resin such as Au-Si, metal, ceramics, etc. having a thickness of about 50 μm, and the wiring layer and the semiconductor element are bonded by wire bonding, TAB tape or the like. Or connect.

As the semiconductor element, Si-based or Ga
Although As-based chip components can be used, they are particularly effective for mounting GaAs-based chip components in terms of approximation of the coefficient of thermal expansion.

Further, a cap made of the same kind of insulating material as the insulating substrate, another insulating material, or a metal having a good heat radiation property and having an electromagnetic wave shielding property is provided on the surface of the wiring board on which the semiconductor element is mounted, with glass, The semiconductor element may be hermetically sealed by bonding with an adhesive such as a resin or a brazing material.

(Structure of Wiring Board) A specific structure of a package for housing a semiconductor element, which is an example of a high-frequency wiring board in which the porcelain composition of the present invention can be suitably used, and a mounting structure thereof will be described with reference to FIG. explain. FIG. 1 is a schematic cross-sectional view of a package A for housing a semiconductor element, in particular, a ball grid array (BGA) type package in which connection terminals are ball-shaped terminals. According to FIG. 1, a package A has a cavity 3 formed by an insulating substrate 1 made of an insulating material and a lid 2, and a chip component 4 such as GaAs is formed in the cavity 3 by the above-mentioned adhesive or the like. Has been implemented.

Also, on the surface and inside of the insulating substrate 1,
A wiring layer 5 electrically connected to the chip component 4 is formed. The wiring layer 5 preferably contains a low-resistance metal such as copper, silver, or gold as a main component in order to minimize conductor loss during transmission of a high-frequency signal. When transmitting a high-frequency signal of 1 GHz or more to the wiring layer 5,
Since it is necessary to transmit a high-frequency signal without loss, the wiring layer 5 is formed of at least one of a known strip line, microstrip line, coplanar line, and dielectric waveguide line.

Further, in the package A of FIG. 1, a connection electrode layer 6 is formed on the bottom surface of the insulating substrate 1 and is connected to the wiring layer 5 in the package A. A ball-shaped terminal 8 is formed on the connection electrode layer 6 with a brazing material 7 such as solder.

In order to mount the package A on an external circuit board, as shown in FIG. 1, wiring is formed on the surface of an insulating substrate 9 made of an insulating material containing an organic resin such as a polyimide resin, an epoxy resin, and a phenol resin. The external circuit board B on which the conductor 10 is formed is mounted via a brazing material. Specifically, the ball-shaped terminal 8 attached to the bottom surface of the insulating substrate 1 in the package A and the wiring conductor 10 of the external circuit board B are brought into contact with each other and soldered with solder 11 such as Pb-Sn. Implemented. Further, the ball-shaped terminal 8 itself may be melted and connected to the wiring conductor 10.

Further, according to FIG. 1, a ball-shaped terminal is used. However, the present invention is not limited to this, and a conductor formed directly on the bottom surface of the package A by soldering without using the ball-shaped terminal is used. It can also be connected to the wiring conductor 10 of the external circuit board B.

According to the present invention, the chip component 4 such as GaAs is mounted by brazing or an adhesive, or is mounted on an external circuit board such as a printed board by brazing with such ball-shaped terminals 8 interposed therebetween. In such a surface mount type package, the difference in thermal expansion between a chip component such as GaAs and an insulating substrate of an external circuit board can be made smaller than that of a conventional ceramic material.
Even when a thermal cycle is applied, the generation of stress in the mounting portion can be suppressed, and as a result, the long-term reliability of the mounting structure can be improved.

[0053]

EXAMPLES Glass the following composition A: SiO ₂ 50.2 wt% -Al ₂ O ₃ 5.0 wt% -MgO16.1 wt% -CaO15.1 wt% -SrO13.6 wt% Glass B: SiO ₂ 47.5 wt% -Al ₂ O ₃ 4.8 wt% -MgO16.8 wt% -CaO14.2 wt% -SrO16.7 wt% glass C: SiO ₂ 52.0 wt% -Al ₂ O ₃ 5. 0 wt% -MgO18.0 wt% -CaO25.0 wt% glass D: SiO ₂ 10.4 wt% -Al ₂ O ₃ 2.5 wt% -B ₂ O ₃ 45.3 wt% -CaO35.2 weight % -Na ₂ O 6.6 wt% containing SrO having an average particle size of 2 μm and capable of precipitating a diopside crystal phase (glasses A and B);
Glass powder C containing no SrO and capable of precipitating a diopside crystal phase and glass powder D not precipitating a diopside crystal phase were prepared.

Then, the fillers (purity: 99%) shown in Tables 1 and 2 were added to the above glass. The average particle size of each filler was 1 μm for the γ-Al ₂ O ₃ powder, and 2 μm for the others.

Further, an organic binder, a plasticizer, and toluene were added to the mixture 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 was subjected to a binder removal treatment in a steam-containing / nitrogen atmosphere at 700 ° C., and then fired in dry nitrogen at the firing temperatures shown in Tables 1 and 2 for 2 hours to obtain a porcelain for an insulating substrate.

The porosity of the obtained porcelain was measured by the Archimedes method, and then the dielectric constant and the dielectric loss were evaluated by the following methods. Measurements were taken for shape, diameter 2-7 mm, thickness 1.
The sample was cut into a shape of 5 to 2.5 mm, and the shape was measured at 60 GHz by a dielectric cylinder resonator method using a network analyzer and a synthesized sweeper. In the measurement, NR
The dielectric resonator was excited by the D guide (non-radiative dielectric line), and the dielectric constant and the dielectric loss were calculated from the resonance characteristics of the TE ₀₂₁ and TE ₀₃₁ modes.

Further, a thermal expansion curve from room temperature to 400 ° C. was taken to calculate a thermal expansion coefficient. Further, the crystal phase in the sintered body was identified from the X-ray diffraction chart.

The ratio of the glass phase in the porcelain was evaluated by the Rietveld method. Specifically, after the porcelain to be evaluated was pulverized, ZnO was added at a predetermined ratio as an internal standard sample, and ethanol was added thereto, followed by wet mixing. After drying, X-ray diffraction measurement was performed, and the ratio of the glass phase present in the porcelain was calculated from the addition ratio of ZnO and the ratio of ZnO and the crystal phase in the porcelain obtained by the Rietveld method.
The ratio of Si in the glass phase was measured by TEM to calculate the ratio in terms of SiO ₂ .

Further, the four-point bending strength of the porcelain was measured based on JISR1601, and the thermal conductivity of a 1 mm thick sample was measured by a laser flash method. Also,
The Young's modulus was measured by an ultrasonic pulse method according to SR1602-1995. The results are shown in Tables 1 and 2.

[0060]

[Table 1]

[0061]

[Table 2]

As is clear from the results in Tables 1 and 2, Si
Sample No. 3 in which the amount of glasses A and B containing O ₂ , Al ₂ O ₃ , MgO, CaO and SrO is less than 40% by weight. One, two
0, it is difficult to sinter at a low temperature, and the relative density 9
It did not densify to more than 7%.

The sample No. 1 in which the amount of γ-Al ₂ O ₃ added was less than 1% by weight. In Nos. 10 and 24, the ratio of the glass phase in the porcelain was high, the dielectric loss was high, and the porcelain strength was low. Further, instead of γ-Al ₂ O ₃ , α-Al ₂ O ₃
Or sample No. to which only mullite was added. In Examples 11 and 12, the ratio of the glass phase in the porcelain was high, and the dielectric loss was low.

A sample N using glass C containing no SrO and capable of precipitating a diopside crystal phase was used as the glass.
o. In Sample No. 29, the porcelain could not be densified at a low temperature of 1000 ° C. or less, and Sample No. 29 using glass D containing a large amount of B ₂ O ₃ was used. Sample No. 30 was melted. Three
In No. 1, a large amount of glass containing boron remained, and the dielectric loss tended to increase.

On the other hand, according to the present invention, a specific amount of γ
-Al ₂ O ₃ -added sample, γ-Al ₂ O ₃
And a dielectric loss at 60 GHz of 30 × 10 ⁻⁴ or less and a coefficient of thermal expansion of 5 × 10 ⁻⁶ /
℃, dielectric constant of 8 or more, and porcelain strength of 250 MPa or more. As a wiring board for transmitting high-frequency signals, it also has high mounting reliability on chip parts such as GaAs and printed circuit boards. It turns out that it can be enhanced.

[0066]

As described in detail above, according to the porcelain composition for high frequency wave of the present invention, since it can be fired at a low temperature of 1000 ° C. or less, a wiring layer made of a low-resistance metal such as copper can be formed. Dielectric loss at 77 GHz is 30 × 10
^{Since the} dielectric loss is as low as ⁻⁴ or less, a high-frequency signal can be transmitted very well without loss in a high-frequency region of 1 GHz or more.

Further, the porcelain obtained using this composition has a high porcelain strength of 250 MPa or more and a dielectric constant of 10 MPa.
Since it can be controlled to a thermal expansion characteristic similar to that of a GaAs chip or a printed circuit board, it has excellent characteristics especially as an insulating substrate of a wiring board,
Provides a highly reliable mounting structure with excellent heat cycle resistance when mounted with s chips or when mounted on a motherboard such as a printed circuit board having an insulating substrate containing organic resin with a brazing material. it can.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining an example of a mounting structure of a package for housing a semiconductor element, which is an example of a high-frequency wiring substrate using a porcelain obtained by firing a composition of the present invention.

[Explanation of symbols]

 Reference Signs List A semiconductor device storage package B external circuit board 1 insulating substrate 2 lid 3 cavity 4 chip component 5 wiring layer 6 connection electrode layer 7 brazing material 8 ball-shaped terminal 9 insulating substrate 10 wiring conductor 11 brazing material

Claims (11)

[Claims] 1. A glass containing SiO ₂ , Al ₂ O ₃ , MgO, SrO and CaO, capable of precipitating a diopside type crystal phase, in an amount of 40 to 99% by weight, and at least γ-Al ₂ O ₃ as a filler. A high-frequency porcelain composition, characterized in that it is contained in an amount of up to 60% by weight. 2. The method according to claim 1, wherein said glass is 30 to 55% by weight of SiO _2.
When, Al ₂ and O ₃ 4 to 15 wt%, and MgO14~30 wt%, and CaO5~20 wt%, high-frequency ceramic composition of claim 1, wherein the consisting of SrO10~25 wt% . 3. At least Mg, Ca, Si, Sr, Al
A diopside-type crystal phase containing at least γ-Al
A high frequency porcelain comprising a ₂ O ₃ crystal phase and having a dielectric loss of 30 × 10 ⁻⁴ or less at 60 to 77 GHz. 4. The high frequency porcelain according to claim 3, wherein the glass phase is contained in a proportion of 30% by weight or less. 5. The high frequency porcelain according to claim 4, wherein said glass phase contains at least 50% by weight of Si in terms of oxide (SiO ₂ ). 6. The thermal expansion coefficient from room temperature to 400 ° C. is 5
× 10 ^-6 / ° C or higher, dielectric constant of 10 or lower, porcelain strength 250
The high frequency porcelain according to any one of claims 3 to 5, wherein the porcelain is at least MPa. 7. The high frequency porcelain according to claim 3, wherein the thermal conductivity is 3 W / m · K or more. 8. A glass containing SiO ₂ , Al ₂ O ₃ , MgO, SrO and CaO and capable of precipitating a diopside-type crystal phase in an amount of 40 to 99% by weight, and at least γ-Al ₂ O ₃ as a filler. After shaping a mixture consisting of at least 60% by weight, the mixture is fired at a temperature of 800 to 1000 ° C., and a diopside type crystal phase containing at least Mg, Ca, Si, Sr and Al, and at least γ-Al ₂ O ₃ A method for producing a high-frequency porcelain, comprising producing a porcelain containing a crystal phase. 9. The glass according to claim 1, wherein said glass is 30 to 55% by weight of SiO _2.
When the Al ₂ O ₃ 4 to 15 wt%, and MgO14~30 wt%, and CaO5~20 wt%, the method of manufacturing the high-frequency ceramics of claim 8, wherein the consist SrO10~25 wt% . 10. The method according to claim 10, wherein:
8. A wiring board provided with a metallized wiring layer, wherein the insulating substrate is made of the high-frequency ceramic according to claim 3. 11. The method according to claim 11, wherein said metallized wiring layer is made of Cu or A.
The wiring board according to claim 10, wherein g is a main component.