JP2012188339A - Ceramic composition, ceramic sintered compact, and electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic composition capable of being sintered at a low temperature, having low dielectric loss in a high frequency range, and from which a ceramic sintered compact having excellent plating corrosion resistance can be obtained, a ceramic sintered compact obtained from the composition, and an electronic component made using the sintered compact.SOLUTION: A ceramic composition includes 6 to 19 pts.mass SrTiOpowder, 1.4 to 6 pts.mass Al component in terms of oxide, 0.3 to 0.9 pts.mass Li component in terms of oxide, 1.6 to 3.2 pts.mass B component in terms of oxide, 3.2 to 5.1 pts.mass Zn component in terms of oxide, 0.5 to 0.9 pts.mass Cu component in terms of oxide, 0 to 3 pts.mass Ag component in terms of oxide, and 0 to 4.5 pts.mass Co component in terms of oxide, and 100 pts.mass diopside crystal powder synthesized by a solid phase reaction method. A ceramic sintered compact and an electronic component are obtained using the composition.

Description

  The present invention is a ceramic composition capable of low temperature sintering, low dielectric loss in a high frequency region, and capable of obtaining a ceramic sintered body excellent in plating corrosion resistance, a ceramic sintered body obtained from the composition, And an electronic component using the sintered body.

  With the recent increase in information capacity and the speed of information communication, it is required to transmit high-frequency signals without loss. For this reason, electronic components such as circuit boards mounted on these devices are required to have low dielectric loss in the high frequency region. In order to transmit high-frequency signals without loss, it is required to form a conductor layer using a low-resistance metal such as copper or silver. In ceramic compositions used for these electronic components, a low-resistance metal is required. Therefore, it is necessary to be able to sinter at a low temperature.

  Diopside is currently attracting attention as one of the materials used in such ceramic compositions. Diopside has a large dielectric constant ε and Q × f value, and is excellent in high frequency characteristics. However, since the temperature coefficient τf of the resonance frequency is large in the diopside, the temperature coefficient of the capacitance becomes large, and a desired dielectric property cannot be obtained depending on the use environment, and particularly when used for an antenna or a filter. Had the problem of narrowing the design tolerance. Thus, various attempts to improve the temperature characteristics of the resonance frequency have been studied.

Patent Document 1 discloses that 30 to 90% by mass of crystallized glass powder for precipitating diopside crystals, 1 to 40% by mass in total of calcium titanate powder and / or strontium titanate powder, Al ₂ O ₃ , TiO ₂ , ZrO ₂ , MgTiO ₃ , BaTi ₄ O ₉ , La ₂ Ti ₂ O ₇ , Nd ₂ Ti ₂ O ₇ , Ca ₂ Nb ₂ O ₇ , SrZrO ₃ , CaZrO ₃ Fe ₂ O ₃ , Cr ₂ O ₃ , ZnO, CuO, Ag ₂ O, Co ₃ O ₄ , MnO ₂ , CeO ₂ , R ₂ O with respect to 100 parts by mass of the mixed powder containing 0 to 60% by mass ₃ (C is a ceramic composition obtained by adding 0.1 to 2.0 parts by mass of at least one powder from R (rare earth element)).

  Further, in Patent Document 2, (a) with respect to 100 parts by mass of the diopside crystal powder synthesized by the solid phase reaction method, (b) 6.0 to 19.0 parts by mass of strontium titanate powder, or 13.0 to 43.0 parts by mass of calcium titanate powder, or 6.5 to 42.0 parts by mass in total of strontium titanate powder and calcium titanate powder, and (c) an alkali compound and an alkaline earth A total of 6.0 to 11.0 masses of powders of two or more compounds selected from a compound, a boron compound, a transition metal compound, a phosphorus compound, and a zinc compound, including a lithium compound and a boron compound, in terms of oxides. A ceramic composition containing a part is disclosed.

JP 2003-286074 A JP 2010-37126 A

  The ceramic composition of Patent Document 1 uses crystallized glass as a raw material. However, crystallized glass is prepared by heating and melting a glass raw material to a melting point or higher, and thus requires heat energy. Moreover, since crystallized glass is produced as a block-like lump, it takes time and effort to powderize it. For this reason, when crystallized glass is used as a raw material, there was a problem that material cost increased. Crystallized glass needs to use a relatively large amount of an auxiliary component in order to enable low-temperature sintering. However, by adding a large amount of an auxiliary component, the characteristics of diopside crystals can be increased. The dielectric loss tends to increase, particularly in the high frequency region.

  On the other hand, the diopside crystal powder synthesized by the solid phase reaction method can be sintered at a low temperature even if the amount of the auxiliary component used is small, and the characteristics of the diopside crystal are hardly impaired. In addition, since each raw material can be synthesized at a temperature below the melting point, it can be synthesized at a lower temperature than crystallized glass, and furthermore, since it is synthesized in powder form, the powdering process is simplified. That's it. For this reason, manufacturing cost can be held down and there is an advantage that it is excellent economically.

  However, the ceramic sintered body obtained by firing the ceramic composition of Patent Document 2 has poor plating resistance, and when an electronic component such as a substrate is manufactured using this ceramic composition, the surface of the conductor layer is plated. During processing, the ceramic layer may be eroded by the plating solution. Plating residue remained at the site eroded by the plating solution, and when moisture in the atmosphere was absorbed, it became an electrolyte solution and migration was easily promoted. Furthermore, there is a problem that the adhesion force between the conductor layer and the ceramic layer is reduced, and the conductor layer is easily peeled off from the ceramic layer.

  Accordingly, an object of the present invention is to provide a ceramic composition capable of obtaining a ceramic sintered body that can be sintered at low temperature, has a low dielectric loss in a high frequency region, and is excellent in plating corrosion resistance, and a ceramic obtained from the composition. An object of the present invention is to provide a sintered body and an electronic component using the sintered body, having a low dielectric loss in a high-frequency region, excellent corrosion resistance against plating, and improved migration.

In order to achieve the above object, the first ceramic composition of the present invention is based on 100 parts by mass of diopside crystal powder synthesized by a solid phase reaction method, 6 to 19 parts by mass of SrTiO ₃ powder, and Al component. 1.4 to 6 parts by mass in terms of oxide, 0.3 to 0.9 parts by mass in terms of oxide of Li component, 1.6 to 3.2 parts by mass in terms of oxide of B component, and oxidation of Zn component 3.2 to 5.1 parts by mass in terms of product, 0.5 to 0.9 parts by mass in terms of oxide of Cu component, 0 to 3 parts by mass in terms of oxide of Ag component, and Co in terms of oxide It contains 0 to 4.5 parts by mass.

The second ceramic composition of the present invention is 13 to 43 parts by mass of CaTiO ₃ powder and 1 component of oxide in terms of oxide with respect to 100 parts by mass of diopside crystal powder synthesized by a solid phase reaction method. 0.4 to 6 parts by mass, Li component in terms of oxide 0.3 to 0.9 parts by mass, B component in terms of oxide 1.6 to 3.2 parts by mass, and Zn component in terms of oxide 3. 2 to 5.1 parts by mass, Cu component to 0.5 to 0.9 parts by mass in terms of oxide, Ag component to 0 to 3 parts by mass in terms of oxide, and Co component to 0 to 4.5 in terms of oxide It is characterized by containing a mass part.

The third ceramic composition of the present invention is a total of 6.5 to 42 parts by mass of SrTiO ₃ powder and CaTiO ₃ powder with respect to 100 parts by mass of diopside crystal powder synthesized by the solid phase reaction method. The Al component is 1.4 to 6 parts by mass in terms of oxide, the Li component is 0.3 to 0.9 parts by mass in terms of oxide, the B component is 1.6 to 3.2 parts by mass in terms of oxide, The Zn component is 3.2 to 5.1 parts by mass in terms of oxide, the Cu component is 0.5 to 0.9 parts by mass in terms of oxide, the Ag component is 0 to 3 parts by mass in terms of oxide, and the Co component is It is characterized by containing 0 to 4.5 parts by mass in terms of oxide.

  It is preferable that 1st-3rd of the ceramic composition of this invention contains 0.5-3 mass parts of said Ag component in conversion of an oxide with respect to 100 mass parts of diopside crystal powder.

  In the first to third ceramic compositions of the present invention, the Co component is preferably contained in an amount of 1.5 to 4.5 parts by mass in terms of oxide with respect to 100 parts by mass of the diopside crystal powder.

  The ceramic sintered body of the present invention is obtained by firing the ceramic composition.

In the ceramic sintered body of the present invention, it is preferable that a SrTiO ₃ crystal and / or a CaTiO ₃ crystal is present alone in any one selected from the interior of the diopsite crystal grain, the grain boundary, and the triple point. In this embodiment, the SrTiO ₃ crystal and / or CaTiO ₃ crystal preferably has an average particle size of 0.5 to 3 μm.

In the ceramic sintered body of the present invention, the absolute value of the temperature coefficient τf of the resonance frequency is preferably 30 × 10 ⁻⁶ / ° C. or less, and the Q × f value is preferably 5000 GHz or more.

  Further, an electronic component of the present invention includes a ceramic layer obtained by firing the ceramic composition, a conductor layer that is on the surface and / or inside the ceramic layer, and is obtained by simultaneous firing with the ceramic composition, It is characterized by having.

  In the electronic component of the present invention, the conductor layer is preferably formed of Ag, Cu, or an alloy containing at least one of them.

  In the electronic component of the present invention, the surface of the conductor layer is preferably subjected to wet plating.

  The electronic component of the present invention is preferably a substrate.

The ceramic composition of the present invention uses a diopside crystal powder synthesized by a solid phase reaction method, so that low temperature sintering is possible even if the amount of auxiliary components other than the diopside crystal powder is small. Is possible. For this reason, the characteristic of a diopside crystal is hard to be impaired. In addition, the diopside crystal powder synthesized by the solid phase reaction method synthesizes each raw material at a temperature below the melting point and is synthesized in a powder form, so that the heat energy required for heating can be reduced, and The manufacturing cost can be reduced by simplifying the labor required for powdering, which is economically superior. Further, by containing a predetermined amount of SrTiO ₃ powder and / or CaTiO ₃ powder, respectively, the temperature coefficient τf of the resonance frequency is controlled while increasing the dielectric constant ε and the Q × f value of the obtained ceramic sintered body. Thus, it can be close to zero. In addition, low-temperature sintering is possible by including a predetermined amount of each of the Li component, B component, Zn component, Cu component, Ag component, and Co component, and in particular, sintering can be performed at a low temperature of 930 ° C. or lower. . And by containing predetermined amount of Al component, the grain boundary structure after sintering becomes strong, the chemical durability of a grain boundary improves, and the sintered compact excellent in plating resistance can be obtained.

  Further, since the ceramic sintered body of the present invention can be sintered at a low temperature, it can be simultaneously sintered with a low-resistance metal such as Cu or Ag, and an electron including these low-resistance metals as a conductor layer. It can be used for ceramic layers of parts. Moreover, since it is excellent in plating resistance, even if the surface of the conductor layer is plated, the ceramic layer can be hardly eroded by the plating solution, and an electronic component in which migration or delamination is unlikely to occur can be obtained.

It is drawing which shows the conductive layer pattern of the sintered compact of an Example. Sample No. It is a graph which shows the moisture-proof test result of 1 and 3 sintered compact.

[Ceramic composition]
The ceramic composition of the present invention contains diopside crystal powder obtained by a solid phase reaction method as a main component. The diopside crystal powder is a ceramic powder made of a non-glass material such as Si, Mg, Ca oxide, carbonate or the like, and a diopside stoichiometric ratio (Ca: Mg: Si = 1: 1: 2). ), Heated below the melting point, sintered by a solid phase reaction method, and pulverized to a predetermined particle size.

The above-mentioned ceramic powder preferably contains Si, Mg, Ca in their oxides, that is, SiO ₂ , MgO, CaO, preferably 53.5 to 62% by mass of SiO ₂ , 12 to 22% by mass of MgO, adjusted to CaO 21-32 wt%, more _preferably, SiO 2 56-59.5 wt%, MgO 15 to 19 wt%, adjusted to a CaO 23.5-29.5 wt% . By adjusting SiO ₂ , MgO, and CaO within the above ranges, it becomes easy to precipitate diopside crystals.

When the content of SiO ₂ exceeds 62% by mass, wollastonite crystals are likely to be generated, the dielectric loss increases, and the strength may decrease. On the other hand, when the content of SiO ₂ is less than 53.5% by mass, an akermanite crystal is likely to be generated, and the dielectric loss may be increased.

  When the content of MgO exceeds 22% by mass, forsterite crystals are likely to be generated, and the strength tends to be reduced. On the other hand, when the content of MgO is less than 12% by mass, wollastonite crystals are likely to be generated, and the dielectric loss tends to increase.

  When the content of CaO exceeds 32% by mass, wollastonite crystals and orkelmanite crystals are likely to be formed, dielectric loss increases, and strength tends to decrease. On the other hand, if the content of CaO is less than 21% by mass, forsterite crystals are likely to be generated, and the strength is likely to be reduced.

  In the present invention, the average particle size of the diopside crystal powder is preferably 0.8 to 2 μm. When the average particle size is less than 0.8 μm, the specific surface area (BET value) increases, and the density tends to decrease when the ceramic composition is made into a green sheet. For this reason, the amount of shrinkage of the sheet tends to increase before and after firing, and when the conductor layer is formed on the ceramic layer by simultaneous firing with the conductor material, the conductor layer is easily peeled off from the ceramic layer. On the other hand, when the average particle size exceeds 2 μm, it is difficult to reduce the thickness of the green sheet when the ceramic composition is formed into a green sheet. In the present invention, the average particle size of the diopside crystal powder means a value measured by a particle size distribution measurement method by a laser diffraction / scattering method.

The ceramic composition of the present invention contains SrTiO ₃ powder and / or CaTiO ₃ powder.

The diopside crystal alone exhibits a characteristic in which the temperature coefficient τf of the resonance frequency is negative (approximately −65 × 10 ⁻⁶ / ° C.). On the other hand, SrTiO ₃ crystal, the temperature coefficient τf of the resonance frequency is the ^{1670 × 10 -6 / ℃, CaTiO} 3 crystals, the temperature coefficient τf of the resonance frequency is the 840 × ^{10 -6} / ℃, respectively resonance alone The temperature coefficient τf of the frequency shows a positive characteristic. For this reason, by containing SrTiO ₃ powder or CaTiO ₃ powder, the temperature coefficient τf of the resonance frequency can be adjusted to approach zero.

The SrTiO ₃ powder was sintered with diopside crystals, and as a crystal phase after sintering, SrTiO ₃ alone or (xCa, 1-xSr) TiO ₃ type perovskite in which calcium was dissolved in SrTiO _3. A compound is produced. Since this perovskite compound has a positive temperature coefficient τf of the resonance frequency, SrTiO ₃ powder increases the temperature coefficient τf of the resonance frequency of the ceramic sintered body containing the diopside crystal with a small addition amount. Let it be close to zero.

Further, the CaTiO ₃ powder easily reacts with SiO ₂ in the diopside crystal by sintering with the diopside crystal to easily generate titanite (or sphene, CaTiSiO ₅ ). Since titanite has a negative frequency characteristic that the temperature coefficient τf of the resonance frequency is −756 × 10 ⁻⁶ / ° C., when titanite is generated, it becomes an obstructive factor in compensating the temperature coefficient τf of the resonance frequency, It is necessary to further add an amount that cancels the temperature coefficient τf of the resonance frequency of titanite.

Here, it is known that the following equation (1) is established empirically for the resonance frequency of a composition in which different kinds of materials are combined.
{Temperature coefficient τf of resonance frequency of composite = Σ (volume fraction of each component (vol%) × temperature coefficient τf of resonance frequency of each component)} (1)

Further, it is known from experience that the following formula (2) holds for the dielectric constant of a composition in which different materials are combined.
{Log (dielectric constant ε of composite) = Σ (volume fraction of each component (vol%) × log (dielectric constant ε of each component)} (2)

The temperature coefficient τf and dielectric constant ε of the resonance frequency of SrTiO ₃ are τf = 1670 × 10 ⁻⁶ and ε = 255, and the temperature coefficient τf and dielectric constant ε of the resonance frequency of CaTiO ₃ are τf = 840 × 10 ⁻⁶ / ° C. and ε = 177.

That is, when it is desired to increase the temperature coefficient τf of the resonance frequency without increasing the dielectric constant ε as much as possible, it is preferable to use SrTiO ₃ powder. Further, when it is desired to increase both the dielectric constant ε and the temperature coefficient τf of the resonance frequency, it is preferable to use CaTiO ₃ powder. Also, when adjusting optionally depending on the application and the temperature coefficient τf of the resonance frequency and the dielectric constant ε, it is preferable to use the SrTiO ₃ powder and CaTiO ₃ powder.

Accordingly, a first aspect of the ceramic composition of the present invention, compared diopside crystal powder 100 parts by weight of the SrTiO ₃ powder containing 6 to 19 parts by weight. If the content of the SrTiO ₃ powder is within the above range, the temperature coefficient τf of the resonance frequency can be brought close to zero while reducing the dielectric loss in the high frequency region.

A second aspect of the ceramic composition of the present invention, compared diopside crystal powder 100 parts by weight, containing 13 to 43 parts by weight of CaTiO ₃ powder. If the content of the CaTiO ₃ powder is within the above range, the temperature coefficient τf of the resonance frequency can be brought close to zero while reducing the dielectric loss in the high frequency region.

A third aspect of the ceramic composition of the present invention, compared diopside crystal powder 100 parts by weight, contains from 6.5 to 42 parts by weight of a SrTiO ₃ powder and CaTiO ₃ powder in total. If the total content of the SrTiO ₃ powder and the CaTiO ₃ powder is within the above range, the temperature coefficient τf of the resonance frequency can be brought close to zero while reducing the dielectric loss in the high frequency region.

In the ceramic composition of the present invention, the SrTiO ₃ powder and the CaTiO ₃ powder have an average particle size of 0 from the viewpoint of controlling the sinterability, increasing the strength of the ceramic sintered body, and controlling the temperature coefficient τf of the resonance frequency. It is preferable to use a powdery material of 5 to 2 μm, and in particular, it is more preferable to use a powdery material of 0.8 to 1.5 μm because the dispersibility is improved with respect to the diopside crystal powder. . In the present invention, the average particle size of the SrTiO ₃ powder and CaTiO ₃ powder means a value measured by the method of particle size distribution measurement by laser diffraction scattering method.

The ceramic composition of the present invention contains an Al component. Examples of the Al component include Al oxides and carbonates. By containing the Al component, the grain boundary structure of the ceramic sintered body obtained is strengthened, and the chemical durability of the grain boundary is improved. For this reason, the ceramic sintered compact excellent in plating resistance is obtained. Al component to diopside crystal powder 100 parts by weight, contains from 1.4 to 6 parts by weight in oxide _(Al 2 _{O 3)} in terms. When the content of the Al component is less than 1.4 parts by mass in terms of oxide, the effect of addition is poor and the plating resistance is poor. Moreover, when it exceeds 6 mass parts, the sinterability of a ceramic composition will fall and it will not sinter at 930 degrees C or less.

The ceramic composition of the present invention contains a Li component. Examples of the Li component include Li oxide and carbonate. By containing the Li component, a liquid phase can be formed during sintering and the sintering temperature of the ceramic composition can be lowered. Li component contains 0.3 to 0.9 parts by mass oxide _(Li 2 O) in terms of relative diopside crystal powder 100 parts by weight. When the content of the Li component is less than 0.3 parts by mass in terms of oxide, the sinterability of the ceramic composition is lowered, and sintering is not performed at 930 ° C or lower. On the other hand, when the amount exceeds 0.9 parts by mass, fusion occurs during sintering, and the shape of the sintered body becomes difficult to stabilize, and the insulating property is easily impaired.

The ceramic composition of the present invention contains a component B. Examples of the B component include B oxides and carbonates. By containing B component, a liquid phase can be formed at the time of sintering and the sintering temperature of the ceramic composition can be lowered. B component, to diopside crystal powder 100 parts by weight, contains from 1.6 to 3.2 parts by weight of an oxide _(B 2 _{O 3)} in terms. When the content of the B component is less than 1.6 parts by mass in terms of oxide, the sinterability of the ceramic composition is lowered and the sintering is not performed at 930 ° C or lower. On the other hand, if it exceeds 3.2 parts by mass, the Q × f value decreases and the dielectric loss increases.

  The ceramic composition of the present invention contains a Zn component. Examples of the Zn component include Zn oxide and carbonate. By containing the Zn component, a liquid phase can be formed during sintering, and the sintering temperature of the ceramic composition can be lowered. Furthermore, water resistance can be improved. The Zn component is contained in an amount of 3.2 to 5.1 parts by mass in terms of oxide (ZnO) with respect to 100 parts by mass of the diopside crystal powder. When the content of the Zn component is less than 3.2 parts by mass in terms of oxide, the sinterability of the ceramic composition is deteriorated and does not sinter at 930 ° C. or lower. On the other hand, if it exceeds 5.1 parts by mass, the Q × f value decreases and the dielectric loss increases.

  The ceramic composition of the present invention contains a Cu component. Examples of the Cu component include Cu oxide and carbonate. By containing a Cu component, a liquid phase can be formed during sintering, and the sintering temperature of the ceramic composition can be lowered. Cu component contains 0.5-0.9 mass part in conversion of an oxide (CuO) with respect to 100 mass parts of diopside crystal powder. When the content of the Cu component is less than 0.5 parts by mass in terms of oxide, the sinterability of the ceramic composition is deteriorated and does not sinter at 930 ° C. or lower. On the other hand, when the amount exceeds 0.9 parts by mass, fusion occurs during sintering, and the shape of the sintered body becomes difficult to stabilize, and the insulating property is easily impaired.

The ceramic composition of the present invention can contain an Ag component as an optional component. Examples of the Ag component include Ag oxide and carbonate. By containing the Ag component, it is possible to prevent the conductor metal from eluting into the liquid phase of the ceramic composition when Ag or an Ag alloy is used as the conductor metal and the ceramic composition and the conductor metal are simultaneously fired. The Ag component can be contained in an amount of 0 to 3 parts by mass, preferably 0.5 to 3 parts by mass, in terms of oxide (Ag ₂ O) with respect to 100 parts by mass of the diopside crystal powder. When the content of the Ag component is less than 0.5 parts by mass in terms of oxide, it is not possible to prevent elution of the conductive metal into the liquid phase of the ceramic composition when the ceramic composition and the conductive metal are fired simultaneously. is there. Moreover, when it exceeds 3 mass parts, it exists in the tendency for plating resistance to fall.

  The ceramic composition of the present invention can contain a Co component as an optional component. Examples of the Co component include Co oxides and carbonates. By containing the Co component, the sinterability can be improved. The Co component can be contained in an amount of 0 to 4.5 parts by mass, preferably 0.5 to 4.5 parts by mass, in terms of oxide (CoO) with respect to 100 parts by mass of the diopside crystal powder. When the content of the Co component is less than 0.5 parts by mass in terms of oxide, the effect of addition is hardly obtained, and when it exceeds 4.5 parts by mass, fusion tends to occur during sintering.

  The ceramic composition of the present invention can further optionally contain a Na component, a K component, a Ca component, a Mg component, a Ba component, a P component, and the like.

By containing the Na component and the K component, water resistance and acid resistance can be improved without significantly impairing the sinterability. The Na component and the K component can be contained in a total amount of 0 to 2 parts by mass in terms of oxide (Na ₂ O, K ₂ O) with respect to 100 parts by mass of the diopside crystal powder.

  Moreover, by containing Ca component, Mg component, and Ba component, a liquid phase can be formed at the time of sintering and sintering temperature can be lowered. The Ca component, Mg component, and Ba component can be contained in a total amount of 0 to 5 parts by mass in terms of oxide (CaO, MgO, BaO) with respect to 100 parts by mass of the diopside crystal powder.

Moreover, by containing P component, a liquid phase can be formed at the time of sintering and the sintering temperature can be lowered. The P component can be contained in an amount of 0 to 2 parts by mass in terms of oxide (P ₂ O ₅ ) with respect to 100 parts by mass of the diopside crystal powder.

[Ceramic sintered body]
The ceramic sintered body of the present invention is prepared by mixing a ceramic composition blended so as to have the above composition under a wet condition such as water using a ZrO ₂ ball or the like, and if necessary, a binder, It is obtained by adding a plasticizer, a solvent, etc., forming into a predetermined shape, and firing.

  Examples of the binder include polyvinyl butyral resin and methacrylic acid resin. Examples of the plasticizer include dibutyl phthalate and dioctyl phthalate. Examples of the solvent include toluene and methyl ethyl ketone. be able to.

  The molding is performed in an arbitrary shape by various known molding methods such as a press method, a doctor blade method, an injection molding method, and tape molding. Among these methods, the doctor blade method and tape molding are particularly preferable for forming a laminate.

  Firing is preferably performed at 850 to 1000 ° C. for 0.5 to 3 hours in a non-oxidizing atmosphere such as air, oxygen atmosphere, or nitrogen atmosphere.

The ceramic sintered body of the present invention thus obtained has SrTiO ₃ crystal and / or CaTiO ₃ crystal alone in any one selected from the interior of the diopsite crystal grain, the grain boundary and the triple point. ing. The average particle size of the SrTiO ₃ crystal and the CaTiO ₃ crystal is preferably 0.5 to 3 μm. If it is less than 0.5 μm, the temperature coefficient τf of the resonance frequency tends to be −30 × 10 ⁻⁶ / ° C. or less. If it exceeds 3 μm, dispersion during wet mixing after calcination becomes poor, and as a result, uneven distribution of SrTiO ₃ crystals and CaTiO ₃ crystals in the sintered body tends to become remarkable. Confirmation of the SrTiO ₃ crystal and the CaTiO ₃ crystal can be confirmed by microscopic observation. In the present invention, the average particle size of SrTiO ₃ crystal and CaTiO ₃ crystal means a value measured by a particle size distribution measurement method by a laser diffraction / scattering method.

  In addition, the ceramic sintered body of the present invention has a high dielectric constant ε and Q × f value, a temperature coefficient τf of resonance frequency is close to zero, excellent plating resistance, and extremely low substrate erosion due to the plating process. is there. Furthermore, it is excellent in water resistance, chemical resistance and mechanical strength.

The ceramic sintered body of the present invention preferably has a dielectric constant ε of 8 to 20. Moreover, it is preferable that Q * f value is 5000 GHz or more. The absolute value of the temperature coefficient τf of the resonance frequency is preferably 30 × 10 ⁻⁶ / ° C. or less.

Since the ceramic sintered body of the present invention can have an absolute value of the temperature coefficient τf of the resonance frequency of 30 × 10 ⁻⁶ / ° C. or less and a Q × f value of 5000 or more, for example, high-frequency components such as circuit boards, filters, and antennas It can be suitably used for electronic components.

[Electronic parts]
Next, the electronic component of the present invention will be described.

  The electronic component of the present invention has a ceramic layer obtained by firing the ceramic composition, and a conductor layer which is on the surface and / or inside of the ceramic layer and obtained by simultaneous firing with the ceramic composition.

  As a material which comprises a conductor layer, a low resistance material is preferable and Ag, Ag alloy, Cu, and Cu alloy are more preferable. Examples of the Ag alloy include an Ag—Pd alloy and an Ag—Pt alloy. Examples of the Cu alloy include a Cu—Ca alloy, a Cu—Mg—Ca alloy, and a Cu—Ni—Fe alloy.

  Examples of the electronic component of the present invention include a single layer substrate, a multilayer substrate, a capacitor, and a filter.

  Hereinafter, a manufacturing example in the case where the electronic component of the present invention is used as a laminated substrate will be described.

  A binder, a solvent, a plasticizer, and the like are added to the ceramic composition of the present invention to prepare a slurry, which is then formed into a thin film by a method such as a doctor blade method to produce a green sheet.

  Next, a conductive paste containing a conductive metal such as Ag, an Ag alloy, Cu, or Cu alloy is printed on the obtained green sheet by a screen printing method or the like to form an unfired internal conductor layer having a predetermined pattern.

  Next, a plurality of green sheets on which the unfired internal conductor layer is formed are stacked and pressure-bonded to produce an unfired laminate.

  Next, the unfired laminate is subjected to binder removal treatment and cut into a predetermined shape to expose the unfired inner conductor layer at the end of the unfired laminate. Then, a conductor paste containing a conductor metal is printed on the end face of the unfired laminate by a method such as a screen printing method to form an unfired base metal.

  Next, the unfired laminated body on which the unfired base metal is formed is fired at 870 ° C. to 930 ° C. for 0.5 to 3 hours in an oxygen atmosphere or a non-oxidizing atmosphere. And co-firing.

  Then, the surface of the base metal obtained by firing the unfired base metal is subjected to a wet plating process such as electrolytic plating to form a plating layer to form an external electrode. By doing so, it is possible to obtain a multilayer substrate in which a conductor layer is formed between the ceramic layers and outside the ceramic layers.

In the electronic component of the present invention, the ceramic layer has a dielectric constant ε of 8 to 20, a Q × f value of 5000 or more, and an absolute value of the temperature coefficient τf of the resonance frequency in the range of −25 to 85 ° C. is 30 × 10 ⁻⁶ / It is below ℃, and has excellent dielectric properties in the high frequency region. Further, since the ceramic layer can be sintered at a temperature at which simultaneous firing with a low-resistance metal such as Ag, Ag alloy, Cu, or Cu alloy is possible, these low-resistance metals can be used as the conductor metal.

SiO ₂ , CaO and MgO powders are weighed at the ratio of each sample composition shown in Tables 1 to 4, wet mixed for 15 hours, dried at 120 ° C., and the dried powder is calcined at 1200 ° C. in the atmosphere for 2 hours. The obtained calcined product was pulverized to produce a diopside crystal powder having an average particle size of 1.1 μm. In this diopside crystal powder, SrTiO ₃ powder, CaTiO ₃ powder, B ₂ O ₃ powder, Li ₂ O powder, CoO powder, ZnO powder, and CuO powder so as to have the oxide ratios shown in Tables 1 and _2. , Ag ₂ O powder and Al ₂ O ₃ powder were respectively weighed and added, wet-mixed for 15 hours, and dried at 150 ° C. An appropriate amount of PVA binder was added to the dried product, and after granulation and press molding, it was heated to 500 ° C. in the atmosphere to remove the binder to obtain a molded body. This molded body was fired at 930 ° C. for 2 hours in the atmosphere, and sample No. 1-80 sintered bodies were obtained.

The crystal phase, sinterability, water absorption, dielectric constant ε, Q × f value, and temperature coefficient τf of each sintered body were evaluated. The results are shown in Tables 5-8. In the crystal phases shown in Tables 5 to 8, Di means diopside crystal, Fo means forsterite crystal, Ak means ochermanite crystal, Wo means wollastonite crystal, ST means It means SrTiO ₃ crystal, CT means CaTiO ₃ crystal, CST means (xCa, 1-xSr) TiO ₃ type perovskite crystal, and Ti means titanite (or sphene) crystal.

  The crystal phase was evaluated by a powder X-ray diffraction (diffractometer method) method using Cu-Kα rays. In addition, the sinterability was evaluated as “◯” when sintered at 930 ° C. and “X” when not sintered. The water absorption was measured based on the underwater Archimedes method. Further, the dielectric constant ε, Q × f value, and temperature coefficient τf were measured at a resonance frequency of 3 GHz to 5 GHz in accordance with JIS R1627. The temperature coefficient τf at the resonance frequency was measured by measuring the temperature change rate between −25 to 85 ° C. of the resonance frequency of 3 GHz to 5 GHz.

  Further, a test body in which an Ag paste was printed on the surface of the ceramic layer made of the sintered body as shown in FIG. 1 and fired at 930 ° C. for 2 hours in the atmosphere to form an Ag conductive layer on the ceramic layer. Got. The obtained test specimen was electrolytically plated with Ni, Cu, and Sn for normal electronic parts, and the Ag conductive layer was covered with a plating layer. The plating erosion distance of the ceramic layer of this sintered body was evaluated. The results are summarized in Tables 5-8.

  The plating erosion distance refers to the depth of the portion exhibiting the grain boundary fracture mode from the surface seen on the fractured surface to the interior of the sintered compact, by breaking the sintered body or chip and observing the fractured surface with an electron microscope. This was measured as the plating erosion distance.

  Sample No. A moisture resistance test was performed using 1 and 3 sintered bodies. The results are shown in FIG. In the humidity resistance test, a voltage of 5 V DC was applied in an environment of a temperature of 85 ° C. and a humidity of 85% using the test body shown in FIG.

  Sample No. From the results of Nos. 1 to 8, sample No. 1 in which the content of the Al component is 1.4 to 6 parts by mass in terms of oxide with respect to 100 parts by mass of the diopside crystal (main component). Nos. 3 to 7 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, Sample No. in which the content of the Al component is less than 1.4 parts by mass with respect to 100 parts by mass of the diopside crystal. 1 and 2 were inferior in plating resistance. And sample No. shown in FIG. As is clear from the results of the moisture resistance tests of Nos. 1 and 3, Sample No. No. 3 was inferior in moisture resistance due to a decrease in resistance over time. Further, Sample No. in which the content of the Al component exceeds 6 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 8 had poor sinterability and was not sintered at 930 ° C.

  Sample No. From the result of 9-15, sample No. whose content of B component is 1.6-3.2 mass parts in conversion of an oxide with respect to 100 mass parts of diopside crystals. Nos. 10 to 14 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, Sample No. whose B component content is less than 1.6 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 9 had poor sinterability and was not sintered at 930 ° C. Further, Sample No. in which the content of Component B exceeds 3.2 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 15 had a small Q × f value and a large dielectric loss.

  Sample No. From the result of 16-21, content of Li component is 0.3-0.9 mass part in conversion of oxide with respect to 100 mass parts of diopside crystals. Nos. 17 to 20 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, Sample No. in which the content of the Li component is less than 0.3 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 16 had poor sinterability and was not sintered at 930 ° C. In addition, Sample No. in which the content of the Li component exceeds 0.9 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 21 was fused during sintering.

  Sample No. From the result of 22-28, content of Co component is 0-4.5 mass parts in conversion of oxide with respect to 100 mass parts of diopside crystals. Nos. 22 to 27 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. In particular, Sample No. in which the content of the Co component is 1.5 to 4.5 parts by mass with respect to 100 parts by mass of the diopside crystal. Nos. 23 to 27 were particularly excellent in sinterability at low temperatures. On the other hand, Sample No. in which the content of the Co component exceeds 4.5 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 28 was fused during sintering.

  Sample No. From the result of 29-34, content of Zn component is 3.2-5.1 mass parts in conversion of oxide with respect to 100 mass parts of diopside crystals. Nos. 30 to 33 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, Sample No. whose Zn component content is less than 3.2 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 29 had poor sinterability and was not sintered at 930 ° C. In addition, Sample No. in which the content of the Zn component exceeds 5.1 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 34 had a small Q × f value and a large dielectric loss.

  Sample No. From the result of 35-39, sample No. whose content of Cu component is 0.5-0.9 mass part in conversion of an oxide with respect to 100 mass parts of diopside crystals. Nos. 36 to 38 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, Sample No. in which the content of the Cu component is less than 0.5 parts by mass in the above ratio. 35 was inferior in sinterability and did not sinter at 930 ° C. Further, Sample No. in which the content of the Cu component exceeds 0.9 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 39 was fused during sintering.

  Sample No. From the results of 40 to 45, Sample No. in which the content of the Ag component is 0 to 3 parts by mass in terms of oxide with respect to 100 parts by mass of the diopside crystal. Nos. 40 to 44 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, Sample No. in which the content of the Ag component exceeds 3 parts by mass with respect to 100 parts by mass of the diopside crystal. No. 45 had poor plating resistance.

Sample No. The results of 46-68, to diopside crystal 100 parts by weight, the sample content of the SrTiO ₃ powder is 6-19 parts by weight No. 47-50, the sample content of CaTiO ₃ powder is 13 to 43 parts by weight No. 53-57, the total content of SrTiO ₃ powder and CaTiO ₃ powder is 6.5 to 42 parts by weight Sample No. All of Nos. 60 to 67 were sintered at 930 ° C. and were excellent in electrical characteristics and plating resistance. On the other hand, the sample No. 2 in which the content of SrTiO ₃ powder and CaTiO ₃ powder is out of the scope of the present invention. 46, 51, 52, 58, 59, and 68 all had large absolute values of the temperature coefficient τf.

  Sample No. From the results of 69 to 80, sample No. In 69, 72, 73, 76, 77, and 80, the composition ratio of the diopside crystal that is the main component greatly deviated from the stoichiometric ratio of diopside (Ca: Mg: Si = 1: 1: 2). In addition, a secondary phase having a larger dielectric loss than that of the diopside was precipitated, the Q × f value was small, and the dielectric loss was large.

Claims (13)

6 to 19 parts by mass of SrTiO ₃ powder, 1.4 to 6 parts by mass in terms of oxide, and Li in terms of oxide for 100 parts by mass of diopside crystal powder synthesized by the solid phase reaction method 0.3 to 0.9 parts by mass, B component is 1.6 to 3.2 parts by mass in terms of oxide, Zn component is 3.2 to 5.1 parts by mass in terms of oxide, and Cu component is an oxide. A ceramic composition comprising 0.5 to 0.9 parts by mass in terms of conversion, 0 to 3 parts by mass of an Ag component in terms of oxide, and 0 to 4.5 parts by mass of a Co component in terms of oxide. 13 to 43 parts by mass of CaTiO ₃ powder, 1.4 to 6 parts by mass of Al component in terms of oxide, and Li component to oxide in terms of 100 parts by mass of diopside crystal powder synthesized by the solid phase reaction method 0.3 to 0.9 parts by mass, B component is 1.6 to 3.2 parts by mass in terms of oxide, Zn component is 3.2 to 5.1 parts by mass in terms of oxide, and Cu component is an oxide. A ceramic composition comprising 0.5 to 0.9 parts by mass in terms of conversion, 0 to 3 parts by mass of an Ag component in terms of oxide, and 0 to 4.5 parts by mass of a Co component in terms of oxide. The total amount of SrTiO ₃ powder and CaTiO ₃ powder is 6.5 to 42 parts by mass with respect to 100 parts by mass of the diopside crystal powder synthesized by the solid phase reaction method, and the Al component is 1.4 to 6 in terms of oxide. Part by mass is 0.3 to 0.9 parts by mass in terms of oxide, Li component is in the range of 1.6 to 3.2 parts by mass in terms of oxide, and Zn is 3.2 to 5 in terms of oxide. 1 part by mass, 0.5 to 0.9 parts by mass of Cu component in terms of oxide, 0 to 3 parts by mass of Ag component in terms of oxide, and 0 to 4.5 parts by mass of Co component in terms of oxide The ceramic composition characterized by the above-mentioned.   The ceramic composition according to any one of claims 1 to 3, wherein the Ag component is contained in an amount of 0.5 to 3 parts by mass in terms of oxide with respect to 100 parts by mass of the diopside crystal powder.   The ceramic composition according to any one of claims 1 to 4, wherein the Co component is contained in an amount of 1.5 to 4.5 parts by mass in terms of an oxide with respect to 100 parts by mass of the diopside crystal powder.   The ceramic sintered compact obtained by baking the ceramic composition of any one of Claims 1-5. The ceramic sintered body according to claim 6, wherein a SrTiO ₃ crystal and / or a CaTiO ₃ crystal is present alone in any one selected from the interior of the diopsite crystal grain, the grain boundary, and the triple point. The ceramic sintered body according to claim 7, wherein an average particle diameter of the SrTiO ₃ crystal and / or the CaTiO ₃ crystal is 0.5 to 3 µm. The ceramic sintered body according to any one of claims 6 to 8, wherein the absolute value of the temperature coefficient τf of the resonance frequency is 30 x 10 ^-6 / ° C or less, and the Q x f value is 5000 GHz or more.   A ceramic layer obtained by firing the ceramic composition according to any one of claims 1 to 5, and a ceramic layer that is on the surface and / or inside of the ceramic layer and is obtained by co-firing with the ceramic composition. An electronic component comprising a conductor layer.   The electronic component according to claim 10, wherein the conductor layer is made of Ag, Cu, or an alloy containing at least one of them.   The electronic component according to claim 10 or 11, wherein a surface of the conductor layer is wet-plated.   The electronic component according to claim 10, wherein the electronic component is a substrate.