Porcelain composition

Abstract

The present invention provides a porcelain composition that suppresses the generation and growth of Ag colloids and the increase in dielectric loss tangent caused by co-firing with Ag. The porcelain composition comprises, in oxide-converted mass percentages, 46-68 mass% SiO2, 20-49 mass% MgO, 0.3-5 mass% Li2O, 0.6-15 mass% Bi2O3, and 0.3-12 mass% B2O3, with the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) being 10 or less.

Description

Technical Field

[0001] The present invention relates to a porcelain composition, and more particularly to a porcelain composition which can be formed into a dielectric porcelain for high frequency use by low temperature firing. Background Art

[0002] Alumina and crystallized glass ceramics are known as dielectric materials useful at high frequencies (particularly frequencies above 10 GHz), and these materials can be used as circuit board materials. Furthermore, as circuit board materials, porcelain compositions are used that are sintered at temperatures of approximately 800 to 1000°C, close to the melting point of metal wiring materials such as Ag and Au, in order to co-fire them with these materials.

[0003] As a ceramic composition that exhibits low loss at high frequencies and is sintered at temperatures of approximately 800-1000°C, Patent Document 1 describes a ceramic composition containing crystallized glass powder and alumina powder, for example. Furthermore, Patent Document 2 describes a ceramic composition containing MgO, SiO2, and a sintering aid.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 4470392

[0007] Patent Document 2: Japanese Patent No. 4202117 Summary of the Invention

[0008] Technical Problems to be Solved by the Invention

[0009] The inventors of the present invention conducted intensive research and discovered that when a porcelain composition containing forsterite (Mg2SiO4) and / or enstatite (MgSiO3) as the primary crystalline phase after firing is simultaneously fired with Ag, a wiring material, the Ag element diffuses into the porcelain during firing and precipitates as Ag colloid after cooling, resulting in an increase in the dielectric loss tangent of the porcelain. Circuit boards using this porcelain composition suffer from a problem in which their characteristics significantly deviate from the designed circuit characteristics.

[0010] Therefore, there is a need for developing a porcelain composition in which the generation and growth of Ag colloid are suppressed and the increase in dielectric loss tangent due to co-firing with Ag as a wiring material is suppressed.

[0011] An object of the present invention is to provide a porcelain composition in which the generation and growth of Ag colloid are suppressed and the increase in dielectric loss tangent due to co-firing with Ag is suppressed.

[0012] Technical means to solve technical problems

[0013] The inventors of the present invention conducted further careful research and found that in the manufacture of porcelain with forsterite (Mg2SiO4) and / or enstatite (MgSiO3) as the main crystalline phase, a porcelain composition containing SiO2, MgO, Li2O, Bi2O3 and B2O3 as essential components and the oxide-converted content of each component being within a specific range can inhibit the generation and growth of Ag colloid and can inhibit the increase in dielectric loss tangent caused by simultaneous firing with Ag as a wiring material, thereby completing the present invention.

[0014] That is, the present invention relates to the following porcelain composition.

[0015] 1. A porcelain composition comprising, in terms of oxide-converted mass%, 46-68 mass% of SiO2, 20-49 mass% of MgO, 0.3-5 mass% of Li2O, 0.6-15 mass% of Bi2O3, and 0.3-12 mass% of B2O3, wherein the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is 10 or less.

[0016] 2. The porcelain composition according to claim 1, wherein the porcelain composition contains, in terms of mass % of oxides, 50 to 64 mass % of SiO2, 24 to 45 mass % of MgO, 0.5 to 3 mass % of Li2O, 0.8 to 8 mass % of Bi2O3, and 0.5 to 4 mass % of B2O3, and the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is 6 or less.

[0017] 3. The porcelain composition according to item 1 or 2, wherein the total content of SiO2, MgO, CaO, ZnO, MnO, NiO, and CoO is 80% by mass or more.

[0018] 4. The porcelain composition according to any one of items 1 to 3, wherein the porcelain composition is used for co-firing with Ag.

[0019] Effects of the Invention

[0020] The porcelain composition of the present invention suppresses the generation and growth of Ag colloid and suppresses the increase in dielectric loss tangent caused by co-firing with Ag. DETAILED DESCRIPTION

[0021] 1. Porcelain composition

[0022] The porcelain produced by firing the porcelain composition of the present invention has a crystalline phase of forsterite (Mg2SiO4) and / or enstatite (MgSiO3) as the main crystalline phase. Hereinafter, when expressing the composition of the porcelain composition, it is expressed as an elemental oxide of a single element for convenience. The porcelain composition of the present invention contains SiO2, MgO, Li2O, Bi2O3, and B2O3. Hereinafter, each component and its content are described. In addition, in this specification, the content of each component of the porcelain composition is expressed in mass % converted into oxides.

[0023] In terms of mass % converted into oxides, the porcelain composition of the present invention contains 46 to 68 mass % of SiO2, 20 to 49 mass % of MgO, 0.3 to 5 mass % of Li2O, 0.6 to 15 mass % of Bi2O3, and 0.3 to 12 mass % of B2O3, and the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is less than 10.

[0024] The porcelain composition of the present invention having the above-mentioned structure contains SiO2, MgO, Li2O, Bi2O3 and B2O3 in specific ranges of content, and the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is less than 10, which can suppress the formation of Ag colloid and the increase in dielectric loss tangent caused by simultaneous firing with Ag as a wiring material.

[0025] (SiO2)

[0026] In the porcelain composition of the present invention, SiO2 is the main component of the porcelain. The SiO2 content is 46-68% by mass, based on 100% by mass of the porcelain composition. If the SiO2 content is outside the above range, sintering at low temperatures becomes difficult. The SiO2 content is preferably 48-66% by mass, and more preferably 50-64% by mass.

[0027] (MgO)

[0028] In the porcelain composition of the present invention, MgO is a major component of the porcelain. The MgO content is 20 to 49% by mass, based on 100% by mass of the porcelain composition. If the MgO content is outside this range, sintering at low temperatures becomes difficult. The MgO content is preferably 22 to 47% by mass, and more preferably 24 to 45% by mass.

[0029] (Li2O)

[0030] In the porcelain composition of the present invention, Li2O is a secondary component that promotes sintering of the porcelain. The Li2O content is 0.3-5% by mass, based on 100% by mass of the porcelain composition. The Li2O content is preferably 0.4-4% by mass, and more preferably 0.5-3% by mass.

[0031] (Bi2O3)

[0032] In the porcelain composition of the present invention, Bi2O3 is a secondary component that promotes porcelain sintering. The Bi2O3 content is 0.6-15% by mass, based on 100% by mass of the porcelain composition. A Bi2O3 content exceeding 15% by mass promotes the formation and growth of Ag colloids, leading to an increase in the dielectric loss tangent due to co-firing with Ag. The Bi2O3 content is preferably 0.7-11% by mass, and more preferably 0.8-8% by mass.

[0033] (B2O3)

[0034] In the porcelain composition of the present invention, B2O3 is a secondary component that suppresses the generation and growth of Ag colloids in the porcelain when the porcelain is fired simultaneously with Ag. The B2O3 content is 0.3 to 12% by mass, based on 100% by mass of the porcelain composition. If the B2O3 content is outside the above range, the generation and growth of Ag colloids in the porcelain will not be sufficiently suppressed when the porcelain is fired simultaneously with Ag. Furthermore, if the B2O3 content exceeds 12%, the water resistance of the sintered porcelain may be reduced. The B2O3 content is preferably 0.4 to 6% by mass, and more preferably 0.5 to 4% by mass.

[0035] In the porcelain composition of the present invention, the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is 10 or less. If this mass ratio exceeds 10, the generation and growth of Ag colloids in the porcelain will not be sufficiently suppressed, and the increase in dielectric loss tangent caused by co-firing with Ag cannot be suppressed. This mass ratio is preferably 7 or less, and more preferably 6 or less.

[0036] (Optional ingredient)

[0037] The porcelain composition of the present invention may contain any component. As the optional component, at least one optional component selected from the group consisting of CaO, ZnO, MnO, NiO and CoO can be listed. The above optional component exhibits an effect similar to MgO, which is the main component of the porcelain, and can adjust various properties such as the temperature dependence of the dielectric constant of the porcelain. When the above optional component is at least one component selected from the group consisting of CaO, ZnO, MnO, NiO and CoO, the content of the above components, i.e., the total content of CaO, ZnO, MnO, NiO and CoO, is preferably 30% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on 100% by mass of the porcelain composition.

[0038] When the porcelain composition of the present invention contains any of the optional components, the total content of the components serving as the main components of the porcelain, namely, SiO2, MgO, CaO, ZnO, MnO, NiO, and CoO, is preferably 80% by mass or greater, more preferably 83% by mass or greater, and even more preferably 86% by mass or greater, based on 100% by mass of the porcelain composition. Furthermore, when the porcelain composition of the present invention contains only a portion of the optional components listed above, the total content of SiO2 and MgO and the content of the optional components only contained in a portion are preferably within the above-mentioned ranges. Furthermore, when the porcelain composition of the present invention does not contain any of the optional components listed above, the total content of SiO2 and MgO is preferably within the above-mentioned ranges.

[0039] Preferably, the porcelain composition of the present invention contains, in terms of oxide-converted mass %, 50-64 mass % SiO2, 24-45 mass % MgO, 0.5-3 mass % Li2O, 0.8-8 mass % Bi2O3, and 0.5-4 mass % B2O3, with the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) being 6 or less. By satisfying the above conditions in the porcelain composition of the present invention, the generation and growth of Ag colloid can be further suppressed, and the increase in dielectric loss tangent caused by co-firing with Ag as a wiring material can be further suppressed.

[0040] As long as the porcelain composition of the present invention can be configured as described above, the type of raw materials is not particularly limited. For example, a mixture of oxides of a single element, such as SiO2 and MgO, can be used. In addition, composite oxides such as MgSiO3 and Li2B4O7 can also be used. Furthermore, compounds that serve as oxide sources (various hydroxides, carbonates, etc.) can also be used.

[0041] The form of the porcelain composition of the present invention is not particularly limited, but is preferably a powder obtained by mixing and pre-firing powders of the above-mentioned oxides and the like to react in advance, and then pulverizing the mixture again.

[0042] The 50% particle size (median diameter) of the porcelain composition of the present invention is not particularly limited. For example, the 50% particle size (D 50 ) can be 0.01 to 10 μm. 50 ) is smaller, the more sufficient sintering properties can be exhibited at a lower firing temperature. 50 ) is preferably 0.1 to 5.0 μm, more preferably 0.2 to 1.0 μm.

[0043] The ceramic composition of the present invention can suppress the generation and growth of Ag colloids even when Ag ions diffuse, and can suppress the increase in dielectric loss tangent caused by co-firing with Ag. That is, the ceramic composition of the present invention is preferably used for co-firing with Ag.

[0044] The dielectric loss tangent of the porcelain densified by adding 1 mass % of Ag2O to the porcelain composition of the present invention and firing at a temperature of 800 to 1000°C is preferably 0.0015 or less, more preferably 0.0010 or less, and even more preferably 0.0008 or less at 10 GHz.

[0045] Because Ag colloid strongly absorbs light with wavelengths between 400 and 500 nm, in addition to measuring the dielectric loss tangent of porcelain produced by adding Ag2O to a porcelain composition and firing it, the production and growth of Ag colloid can also be easily evaluated by the porcelain's color tone. For example, the lower the diffuse reflectance at a wavelength of 450 nm, the greater the amount of Ag colloid. This metric can be helpful in designing the composition of porcelain compositions. However, when the porcelain composition contains a high concentration of coloring components such as MnO, CoO, and NiO, resulting in a darker color than that caused by Ag colloid, evaluation by color tone is not appropriate, and measurement of the dielectric loss tangent is required.

[0046] The ceramic composition of the present invention can be used to produce a laminated substrate by known methods. For example, a green sheet can be formed using a doctor blade method, a conductor paste is printed on the substrate surface, the sheets are stacked and crimped, and then fired at a temperature of 800 to 1000°C to obtain a laminated substrate.

[0047] 2. Preparation method of porcelain composition

[0048] The method for preparing the porcelain composition of the present invention is not particularly limited. For example, the powders of the raw materials such as oxides can be mixed and pre-fired to react in advance as described above, and then pulverized again to prepare the porcelain composition of the present invention in the form of powder.

[0049] The calcination temperature is not particularly limited as long as it is a temperature at which the oxides and the like serving as raw materials can react, but is preferably 700 to 1000°C, more preferably 750 to 900°C.

[0050] The calcination time is not particularly limited as long as the oxides and the like serving as raw materials can react, but is preferably 0.1 to 100 hours, more preferably 1 to 30 hours.

[0051] The method for pulverizing the calcined oxides is not particularly limited, and the pulverization can be performed, for example, by using a bead mill, a jet mill, etc. In addition, after pulverization, the powder can be classified by a method such as airflow classification to adjust the particle size distribution.

[0052] The porcelain composition of the present invention can be produced by the production method described above.

[0053] Example

[0054] Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the embodiments of the present invention.

[0055] (Preparation of Porcelain Composition)

[0056] As raw material powders, SiO2, Mg(OH)2, Li2CO3, Bi2O3, and Li2B4O7 were prepared. The raw material powders were mixed so that the oxide-converted composition was the value shown in Table 1, and pulverized to obtain a raw material mixed powder. The raw material mixed powder was calcined at 850°C for 24 hours, and the calcined product was pulverized again to produce a 50% particle size (D 50 )=0.5~0.6μm of the porcelain composition powder. In addition, the 50% particle size (D 50 ) was measured using a laser diffraction-scattering particle size distribution measuring instrument (model name "MT-3300", manufactured by Nikkiso Co., Ltd.).

[0057] [Evaluation method]

[0058] For the porcelain compositions prepared in Examples and Comparative Examples, samples were prepared and subjected to the following measurements.

[0059] (Sample Preparation)

[0060] The porcelain composition powder was compressed into pellets and then fired at 900°C or 950°C for 1 hour to produce a sintered body. Separately, a powder of the porcelain composition powder and Ag2O was mixed at a mass ratio of 99:1. This powder was also compressed into pellets and fired to produce an Ag2O-added sintered body.

[0061] Next, the surfaces of the sintered body and the Ag2O-added sintered body were polished to produce samples for measuring diffuse reflectance. Separately, the sintered body and the Ag2O-added sintered body were ground and polished to a diameter of 15.5 mm and a height of 7.8 mm to produce samples for measuring dielectric properties.

[0062] (Diffuse reflectivity)

[0063] Using a spectrophotometer (model "U-3010," manufactured by Hitachi High-Technologies Corporation) equipped with an integrating sphere, diffuse reflected light, including regular reflection, was measured at an incident light angle of 10 degrees. A standard white plate composed of Al2O3 was used as a standard sample. Table 1 shows the measured values ​​at 450 nm.

[0064] (Dielectric properties (relative permittivity, dielectric loss tangent))

[0065] As dielectric properties, the relative permittivity and dielectric loss tangent at 10 GHz were measured using a method in accordance with JIS R1627, "Microwave-Used Microwave Ceramics: Dielectric Properties Test Methods." Measurements were made using a PNA network analyzer N5227A manufactured by Keysight Technologies, Inc.

[0066] Table 1 shows the compositions and evaluation results of Examples and Comparative Examples.

[0067]

[0068] According to the results in Table 1, in Comparative Examples 1 and 2, the diffuse reflectivity of the sintered body with 1% Ag2O added is 22% or 34% (i.e., both are less than 50%), while in Examples 1 to 10, the diffuse reflectivity is 55 to 89% (i.e., both are above 50%), which inhibits the generation of Ag colloid.

[0069] Furthermore, the dielectric loss tangent of the sintered body of Comparative Example 1, which had 1% Ag2O added, was a high value of 0.0016. However, in Example 1, the dielectric loss tangent was a low value of 0.0006, indicating that Example 1 suppressed the generation and growth of Ag colloids and suppressed the increase in dielectric loss tangent.

[0070] Industrial Applicability

[0071] The porcelain composition of the present invention suppresses the generation and growth of Ag colloid and suppresses the increase in dielectric loss tangent due to co-firing with Ag, and can therefore be used as a wiring material for co-firing with Ag.

Claims

1. A porcelain composition, wherein: In terms of mass % converted into oxides, the porcelain composition contains 46-68 mass % of SiO2, 24-49 mass % of MgO, 0.3-5 mass % of Li2O, 0.6-15 mass % of Bi2O3, and 0.3-12 mass % of B2O3, and the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is less than 10. The main crystalline phase of the porcelain composition after firing is forsterite Mg2SiO4 and / or enstatite MgSiO3.

2. The porcelain composition according to claim 1, wherein In terms of mass % converted into oxides, the porcelain composition contains 50-64 mass % of SiO2, 24-45 mass % of MgO, 0.5-3 mass % of Li2O, 0.8-8 mass % of Bi2O3, and 0.5-4 mass % of B2O3, and the mass ratio of Bi2O3 to B2O3 (Bi2O3 / B2O3) is less than 6.

3. The porcelain composition according to claim 1 or 2, wherein The total content of SiO2, MgO, CaO, ZnO, MnO, NiO and CoO is 80% by mass or more.

4. The porcelain composition according to claim 1 or 2, wherein The porcelain composition is used for co-firing with Ag.

5. The porcelain composition according to claim 3, wherein The porcelain composition is used for co-firing with Ag.

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