JPH09235160A - Ceramics composition and production of ceramics ware - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain ceramics composition bakable at 800-1000 deg.C, having high relative dielectric constant and low dielectric loss tangent even in a high-frequency region of >=1GHz and exhibiting high strength and provide a process for the production of the ceramics composition. SOLUTION: This ceramics composition is composed of 10-40wt.% of a crystallized glass containing at least B2 O3 , SiO2 , Al2 O3 and ZnO, 5-70wt.% of SrTiO3 and 1-70wt.% of Al2 O3 . A powdery mixture of the above composition is formed and baked in a non-oxidizing atmosphere at 800-1000 deg.C to obtain ceramics containing a perovskite-type crystal phase containing at least Sr and Ti, a spinel-type crystal phase containing at least Zn and Al, a rutile-type crystal phase and an Al2 O3 crystal phase as the constituent crystal phases and having a dielectric constant of >=10 and a transverse rupture strength of >=20kg/mm<2> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porcelain composition which can be fired at a low temperature and is particularly suitable for a multi-layer substrate having copper as a wiring. The present invention relates to a wiring board, a dielectric resonator used in a microwave or millimeter wave region, a dielectric waveguide, and a porcelain used for a dielectric antenna.

[0002]

2. Description of the Related Art In recent years, with the era of advanced information technology, information transmission tends to be faster and higher in frequency. Mobile media such as mobile phones and personal radios, satellite broadcasting, satellite communications, and new media such as CATV have been working to reduce the size of their devices. As a result, microwave circuit elements such as dielectric resonators have been required. In addition, miniaturization is strongly desired.

[0003] The size of such a microwave circuit element is based on the wavelength of the electromagnetic wave used. The wavelength λ of an electromagnetic wave propagating in a dielectric having a relative permittivity εr is λ = λ ₀ / (εr) ^1/2 , where λ ₀ is the propagation wavelength in vacuum. Therefore, the circuit element becomes smaller as the permittivity of the circuit board used increases.

Further, in order to prevent the substrate from being broken or chipped due to the stress applied to the substrate in the process of connecting various electronic parts, input / output terminals, etc. to the multilayer circuit board, a mechanical material is used. High strength is also required.

Therefore, in order to satisfy the above-mentioned requirements for higher dielectric constant and higher strength, for example, Japanese Patent Laid-Open No. 06-13
Japanese Patent No. 2621 proposes a circuit board in which inorganic dielectric particles are dispersed in a resin and which is reinforced with a high dielectric constant glass fiber. Since this circuit board has a high relative dielectric constant, it can promote miniaturization of equipment, and has high strength because it is reinforced with a high dielectric constant glass fiber.

As an insulating material suitable for a circuit board having copper as a wiring layer, a glass ceramic material which can be fired at 800 to 1000 ° C. is known. This glass-ceramic material is used for glass powder such as borosilicate glass and Al ₂
This is fired by adding a filler powder such as ceramics such as O ₃ and quartz, and is advantageous in that a multilayer can be formed by simultaneous firing with copper wiring.

[0007]

However, in the circuit board disclosed in Japanese Unexamined Patent Publication No. 06-132621, the firing temperature is about 400 ° C., and copper or the like is used as the wiring conductor to form a multilayered wiring and fine wiring. There was a problem that I could not do it.

Further, most of the conventional glass ceramic materials have a low dielectric constant lower than the dielectric constant of 10. Therefore, in terms of increasing the dielectric constant for downsizing high frequency equipment. It has not been sufficiently studied, and the strength is at most about 20 kg / mm ² , and further improvement in strength is desired.

Therefore, according to the present invention, a porcelain composition which can be fired at 800 to 1000 ° C. and has a high relative dielectric constant and a low dielectric loss tangent and a high strength even in a high frequency region of 1 GHz or more, and It is intended to provide a manufacturing method.

[0010]

DISCLOSURE OF THE INVENTION As a result of earnest studies on the above-mentioned problems, the present inventor made use of the softening flow of glass to obtain 80
By firing at 0 to 1000 ° C., it is possible to use gold, silver, and copper as wiring conductors for multilayering and fine wiring, and high-dielectric constant SrTiO ₃ , Al ₂ O ₃ , and As a crystal phase, a perovskite type oxide crystal phase such as SrTiO ₃ or Ti
By precipitating an O ₂ (rutile type) crystal phase and an Al ₂ O ₃ crystal phase, it is possible to obtain a high relative dielectric constant, and as a crystal phase, a spinel type crystal phase (ZnO.
_{Al 2 O 3, MgO · Al} 2 O 3) was allowed to precipitate by finding that it is possible to achieve a high strength by completely crystallized glass phase, leading to the present invention.

That is, the porcelain composition of the present invention comprises 10 to 40% by weight of glass containing at least B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ and ZnO, 5 to 70% by weight of SrTiO ₃ , and Al. ₂ O ₃ is composed of 1 to 70% by weight, and a constituent crystal is obtained by molding a mixed powder of such a composition and then firing the mixture at 800 ° C. to 1000 ° C. in a non-oxidizing atmosphere. As a phase, at least Sr
And a perovskite-type crystal phase containing Ti, and at least Z
A porcelain containing a spinel type crystal phase containing n and Al, a rutile type crystal phase and an Al ₂ O ₃ crystal phase and having a dielectric constant of 10 or more and a bending strength of 20 kg / mm ² or more is obtained. It is a thing.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The porcelain composition of the present invention comprises 10 to 40% by weight of a glass component containing at least B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ and ZnO, and 5% SrTiO ₃ as a filler component. ~ 70 wt% and 1 Al ₂ O ₃
It is contained in a proportion of ˜70% by weight.

Here, the composition is limited to the above range because the glass component containing at least B ₂ O ₃ , SiO ₂ , Al ₂ O ₃ and ZnO is less than 10% by weight,
In other words, when the amount of the filler component composed of SrTiO ₃ and Al ₂ O ₃ is more than 90% by weight, it is 800 to 1000.
At a temperature of ℃, the porcelain cannot be sufficiently densified, and conversely, if the glass amount is more than 40% by weight, in other words, the filler amount is less than 60% by weight, 700 ° C.
This is because it becomes dense at the following low temperature and cannot be fired at the same time as the wiring conductor such as copper. The desirable range of the glass is 10 to 30% by weight.

On the other hand, in the filler component, SrTiO 3
The amount of ₃ is less than 5% by weight, or the amount of Al ₂ O ₃ is 7
When it is more than 0% by weight, the dielectric constant becomes lower than 10, and Sr
When the content of TiO ₃ is more than 70% by weight or the amount of Al ₂ O ₃ is less than 1% by weight, the dielectric constant is more than 50, and the conductor loss becomes 50 dB / m or more in the high frequency region of 10 to 20 GHz or more, Is difficult to propagate. Particularly, it is desirable that SrTiO ₃ is 10 to 50% by weight and Al ₂ O ₃ is 20 to 50% by weight.

The specific composition of the above glass component is as follows: B ₂ O ₃ 42-50% by weight, SiO ₂ 8-15% by weight, Al ₂ O ₃ 1.5-3% by weight, ZnO 32-40.
It is contained in a weight percentage, and other components such as Na ₂ O and Li _{2 are included.}
O, K ₂ O and other alkali metal oxides of 5.5 to 7.5
You may contain in the ratio of weight%.

This porcelain composition can be densified to a relative density of 95% or more by firing in a temperature range of 800 to 1000 ° C. As a specific method for producing a porcelain, the above composition is molded into an arbitrary shape by a desired molding means, for example, a mold press, a cold isostatic press, an extrusion molding, a doctor blade method, a rolling method, or the like, Atmosphere and N ₂
Firing is performed at a temperature of 800 to 1000 ° C., particularly 900 to 1000 ° C. in a non-oxidizing atmosphere such as Ar or Ar.

The porcelain obtained by this firing contains Sr and Ti as constituent crystal phases, for example, SrTiO 3.
Perovskite type oxide crystal phase such as ₃ and Zn and A
a spinel type crystal phase such as ZnAl ₂ O ₄ (gurnite) and a TiO ₂ (rutile type) crystal phase containing 1
It contains an Al ₂ O ₃ crystal phase.

Therefore, FIG. 1 shows a schematic view of the structure of the porcelain obtained by firing. As shown in FIG. 1, the porcelain according to the present invention is a perovskite type oxide (SrTiO ₃ ).
Crystal phase 1, spinel type (Gurnite: ZnAl ₂ O ₄ )
Crystal phase 2, TiO ₂ (rutile type) crystal phase 3, Al ₂
It is composed of an O ₃ crystal phase 4 and a glass phase 5.

Perovskite type oxide (SrTiO ₃ ).
Crystal phase 1 exists as the main crystal phase in the porcelain. The spinel type crystal phase is ZnO.Al ₂ O ₃ or MgO.
It is a crystal phase of Al ₂ O ₃ . Further, the glass is almost crystallized, and the remaining glass phase 5 exists at the triple point, but it is rarely confirmed.

In this structure, perovskite type oxide crystals, spinel type crystals, Al ₂ O ₃ crystals, TiO ₂
It is desirable that the abundance ratio of the (rutile) crystals decreases in the order. Note that perovskite oxide crystal phase 1, as particles with an average particle diameter of 0.1 to 1 [mu] m, the spinel-type crystalline phase 2, as particles having an average particle size of 0.1 to 1 [mu] m, TiO ₂
The (rutile type) crystal phase 3 has a mean particle size of 0.1 to 1 μm, and the Al ₂ O ₃ crystal phase 4 has a mean particle size of 0.1.
It is desirable to exist as particles of ˜1 μm. In addition,
The above average particle diameters are all average values in the major axis.

As described above, according to the present invention, the relative dielectric constant is improved by allowing the perovskite type oxide (SrTiO ₃ ) crystal phase to exist in the sintered body and the TiO ₂ (rutile type) crystal phase at the same time. can do. Further, the firing temperature is adjusted to cause most of the glass to react, and a spinel type crystal phase is precipitated in the sintered body. Since these crystal phases exist in a form that reinforces the network of each crystal phase, a sintered body having high mechanical strength can be obtained.

The porcelain composition according to the present invention is preferably gold,
It can be used as an insulating substrate for wiring silver, copper, etc. Specifically, as a starting material, B ₂ O ₃ —SiO ₂ is used.
₂ -Al ₂ O ₃ -ZnO glass powder, SrTiO ₃ powder as a filler component, and Al ₂ O ₃ powder are mixed so as to satisfy the above-mentioned composition.

In addition to the oxide powder of each metal, the filler component may be added in the form of carbonate, acetate, nitrate or the like which can form an oxide during the sintering process. In the composition, the SrTiO ₃ powder is preferably a fine powder having a particle size of 1.5 μm or less, particularly 1.0 μm or less in order to enhance the dispersibility and obtain a high dielectric constant and a low dielectric loss tangent. Al ₂ O ₃ powder also has high dispersibility and high dielectric constant SrT.
It is desirable that the fine powder has a particle size of 1.5 μm or less, particularly 1.0 μm or less so that the desired dielectric constant can be stably obtained by combination with iO ₃ .

After appropriately adding a binder to the mixed powder mixed and mixed in the above proportions, the mixture is molded into a predetermined shape and N
₂ , 80 in a non-oxidizing atmosphere such as Ar or in the air
It is obtained by firing at 0 ° C to 1000 ° C for 0.1 to 5 hours. If the firing temperature at this time is lower than 800 ° C, the porcelain will not be sufficiently densified, and if it exceeds 1000 ° C, the copper conductor cannot be used.

When a wiring board is manufactured using such a porcelain composition, for example, the mixed powder prepared as described above is insulated by a known tape molding method such as a doctor blade method or a rolling method. After producing a green sheet for forming a layer, a metal paste containing silver, gold, copper powder, particularly preferably copper powder is used as a metallization for a wiring layer on the surface of the sheet, and a wiring pattern is formed on the surface of the green sheet. Screen printing is performed on the sheet, and in some cases, a through hole is formed in the sheet, and the paste is filled in the hole. Then, after laminating and pressing multiple sheets,
800 to 1000 ° C in a non-oxidizing atmosphere such as N ₂ or Ar
By firing at the temperature of, the wiring layer and the insulating layer can be fired at the same time.

The present invention will be described below with reference to the following examples.

[0027]

【Example】

 Example 1 As the glass, glass having five compositions shown in Table 1 was prepared.

[0028]

[Table 1]

As the filler component, the average particle size is 1
SrTiO _{3 of} less than μm, average particle size is 0.3 μm, 1 μm
And 2 μm Al ₂ O ₃ powder were mixed according to the composition of Table 2. Then, an organic binder, a plasticizer,
Toluene is added and the thickness is 30 by the doctor blade method.
A 0 μm green sheet was prepared. Then, five green sheets are laminated, and at a temperature of 50 ° C., 100 kg /
Thermocompression bonding was performed by applying a pressure of ² cm ² . The obtained laminate was debindered at 700 ° C. in a water vapor-containing / nitrogen atmosphere, and then fired in dry nitrogen under the conditions shown in Table 2 to obtain a sintered body of the ceramic composition for a multilayer substrate.

The dielectric constant and flexural strength of the obtained sintered body were evaluated by the following methods. Dielectric constant is 5 for sample shape
A sample with a thickness of 0 mm and a thickness of 1 mm was cut out and measured at 10 GHz by a dielectric cylinder resonator method using a network analyzer and a synthesized sweeper. In the measurement, a dielectric substrate of a sample was sandwiched between φ50 Cu plate jigs. From the resonance characteristics of the TE011 mode of the resonator,
The dielectric constant was calculated. The bending strength is 70m for the sample shape.
m, thickness 3 mm, width 4 mm, JIS-C-2141
A three-point bending test was carried out in accordance with the regulations of. The measurement results are shown in Table 2.

As a comparative example, TiO ₂ was used as a filler component instead of SrTiO ₃ , and a sintered body was similarly prepared and evaluated (Samples Nos. 23 and 24). Also,
Samples Nos. 19 to 22 were evaluated in the same manner by using glasses C and D using SrTiO ₃ powder having an average particle size of 1.0 μm and Al ₂ O ₃ powder having an average particle size of 0.3 μm as fillers. .

[0032]

[Table 2]

As is clear from the results shown in Table 2, the perovskite type oxide (SrTiO ₃ ) crystal phase as the crystal phase,
A spinel type (Gurnite: ZnAl ₂ O ₄ ) crystal phase,
In the present invention in which a TiO ₂ (rutile type) crystal phase and an Al ₂ O ₃ phase are precipitated, the dielectric constant is 10 or more, the dielectric loss tangent at 10 GHz is 15 × 10 ⁻⁴ or less, and the strength is 20 kg / mm.
A high value of ² or more was shown.

On the other hand, in sample No. 1 containing less than 10% by weight of glass, densification cannot be achieved unless the firing temperature is raised to 1400 ° C., and the relative dielectric constant is higher than 50 and the dielectric loss tangent is It was expensive.

As a comparative example, Ti is used as a filler.
In samples No. 23 and No. 24 using O ₂ , the dielectric loss tangents were 100 and 120, respectively, which were considerably high. Also,
In Samples Nos. 19 to 22 using the crystallized glasses C and D, the glass had a high softening point, so that it could not be sufficiently densified at 800 ° C. to 1000 ° C.
It was not possible to obtain a high-strength sintered body.

[0036]

As described above in detail, the low temperature fired porcelain composition of the present invention exhibits a high dielectric constant and a low dielectric loss tangent in a high frequency band of 1.0 GHz or higher, and has a high strength. The circuit element for use can be downsized, and the strength of the board material can be increased, and the reliability of the board in the bonding of leads to the input / output terminal and the mounting can be improved. Moreover, since the firing can be performed at 800 to 1000 ° C., the wiring made of Au, Ag, Cu or the like can be formed by the simultaneous firing.

[Brief description of drawings]

FIG. 1 is a schematic view of the structure of the porcelain composition of the present invention.

[Explanation of symbols]

1 Perovskite type oxide crystal phase 2 Spinel type crystal phase 3 TiO ₂ (rutile type) crystal phase 4 Al ₂ O ₃ crystal phase 5 glass phase

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical indication // H01L 23/15 H01L 23/14 C

Claims (3)

[Claims] 1. At least B ₂ O ₃ , SiO ₂ , Al ₂ O
10-40% by weight of glass containing ₃ and ZnO, and Sr
₅ to 70% by weight of TiO _{3 and 1} to 70% by weight of Al ₂ O ₃
A porcelain composition comprising: 2. At least Sr and Ti as constituent crystal phases.
A perovskite-type crystal phase, a spinel-type crystal phase containing at least Zn and Al, and a rutile-type crystal phase,
A porcelain composition containing an Al ₂ O ₃ crystal phase, having a dielectric constant of 10 or more and a bending strength of 20 kg / mm ² or more. 3. At least B ₂ O ₃ , SiO ₂ , Al ₂ O
10-40% by weight of glass containing ₃ and ZnO, S
5 to 70 wt% of rTiO ₃ and 1 to 70 of Al ₂ O ₃
A method for manufacturing a porcelain, which comprises firing a mixed powder containing the powder in a weight percentage of 800% to 1000 ° C in a non-oxidizing atmosphere after molding.