JP2005225719A - Dielectric ceramic composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric ceramic composition which exhibits high relative dielectric constant εr and high Qf in a high frequency band exceeding GHz, and has a good temperature coefficient τεr of the relative dielectric constant. <P>SOLUTION: The dielectric ceramic composition contains a main component including a dielectric oxide having a composition expressed by formula: (Sr<SB>1-x</SB>Ca<SB>x</SB>)<SB>m</SB>TiO<SB>3</SB>and an oxide of Cr as a first subcomponent. In the formula, x and m are each a molar ratio in the composition and satisfy 0.32<x<0.42 and 0.965<m<1.035, respectively. The first subcomponent is contained in an amount of >0 and <1 mol based on 100 mol of the main component. The dielectric ceramic composition exhibits the characteristics that the relative dielectric constant εr is ≥200, and the product Qf of the quality factor Q (=1/tanδ, tanδ: dielectric loss tangent) and f is ≥4,000 (GHz), in resonance frequency f derived from TE<SB>011</SB>mode in GHz band, and the absolute value ¾τεr¾ of the temperature coefficient τεr of the relative dielectric constant within a temperature range of -40 to 85°C is ≤1,000 (ppm/°C). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dielectric ceramic composition, and more particularly to a dielectric ceramic composition having a high relative dielectric constant and a high Qf in a high frequency band such as a GHz band and having a good temperature characteristic of the relative dielectric constant.

In recent years, miniaturization, weight reduction, and speeding up of communication devices have been strongly desired. Among them, the frequency band of radio waves used for portable mobile communications such as digital cellular phones and satellite communications is in the high frequency band of mega to giga Hz band (referred to as “GHz band”). Amid the rapid development of used communication equipment, the housing, board, and electronic elements have been miniaturized and densely mounted. However, the communication equipment that supports the high frequency band has been further reduced in size and weight. In order to achieve this, materials such as substrates used in communication equipment must be excellent in high-frequency transmission characteristics (low dielectric loss) in the GHz band. Here, the dielectric loss is proportional to the product of the frequency, the relative dielectric constant εr of the substrate, and the dielectric loss tangent (hereinafter referred to as tan δ). Therefore, in order to reduce the dielectric loss, tan δ of the substrate must be reduced. Further, since the wavelength of the electromagnetic wave in the substrate is shortened to 1 / (εr) ^0.5 , the substrate can be downsized as the relative dielectric constant εr increases. As described above, a circuit board used for a small communication device, electronic device, or information device used in a high frequency band has a high relative dielectric constant εr and Qf (quality factor Q = 1 / tan δ, f = resonance frequency). Is required to be large. In addition, it is important for exhibiting stable characteristics that the variation of the relative dielectric constant εr is small with respect to a change in temperature in an environment where the device is used.

  As a material for such a circuit board, a dielectric material (sintered body) as an inorganic material and a fluorine resin or the like as an organic material are used. However, a substrate made of a dielectric material has problems in dimensional accuracy and workability, and is fragile, so that there is a problem that chips and cracks are likely to occur. On the other hand, a substrate made of an organic material such as a resin has the advantage of being excellent in moldability and workability, but has a problem that the relative dielectric constant εr is small. Therefore, in recent years, in order to obtain a substrate having both advantages, for example, in Patent Document 1 (Japanese Patent No. 2617639), a powder made of a dielectric material is mixed in a resin material as a composite of an organic material and an inorganic material. A composite substrate is proposed.

  On the other hand, various compositions have been developed as dielectric material compositions, such as Patent Document 2 (Japanese Patent Laid-Open No. 2001-20229) and Patent Document 3 (Japanese Patent Laid-Open No. 2002-294938). . Patent Document 2 and Patent Document 3 are premised on constituting a multilayer ceramic capacitor. Therefore, Patent Documents 2 and 3 provide dielectric ceramic compositions that are excellent in reduction resistance during firing, have excellent capacity-temperature characteristics after firing, and can improve the accelerated life of insulation resistance. It is an issue. However, since the multilayer ceramic capacitor is premised on use in the MHz band, Patent Documents 2 and 3 do not discuss the relative permittivity εr and Qf in the GHz band and the temperature characteristic τεr of the relative permittivity.

Japanese Patent No. 2617639 JP 2001-220229 A Japanese Patent Laid-Open No. 2002-294938

  The present invention has been made on the basis of the above background. A dielectric ceramic composition having a high relative dielectric constant εr and a high Qf in a high frequency band such as a GHz band and a good temperature characteristic τεr of the relative dielectric constant. The purpose is to provide.

For this purpose, the dielectric ceramic composition of the present invention includes a main component containing a dielectric oxide having a composition represented by (Sr _1-x Ca _x ) _m TiO ₃ and oxidation of Cr as a first subcomponent. Symbols x and m indicating the composition molar ratio in the formula included in the main component are 0.32 <x <0.42, 0.965 <m <1.035, and the main component is 100 mol. On the other hand, the first subcomponent is characterized by containing less than 1 mol (not including 0) in terms of Cr in the oxide. Here, the first subcomponent has the effect of improving the relative dielectric constant εr and the specific resistance ρ in the high frequency band and lowering the firing temperature. In addition, a part of the Cr oxide as the first subcomponent can be replaced with the Mn oxide.

  The dielectric ceramic composition according to the present invention further includes an oxide of X (where X is one or more elements selected from V, Nb, W, Ta and Mo) as the second subcomponent. It is preferable to contain less than 2 mol (excluding 0) in terms of X in the oxide with respect to 100 mol of the main component. This second subcomponent has the effect of lowering the firing temperature and improving the relative permittivity εr and Qf in the high frequency band.

  The dielectric ceramic composition according to the present invention further includes, as a third subcomponent, R (where R is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Less than 2 mol (excluding 0) in terms of R in the oxide with respect to 100 mol of the main component of oxide of Er, Tm, Yb and Lu) It is preferable to contain. This third subcomponent has the effect of improving the temperature characteristic τεr of the relative dielectric constant in the high frequency band.

The dielectric ceramic composition according to the present invention further includes, as a fourth subcomponent, SiO ₂ , MO (where M is one or more elements selected from Ba, Ca, Sr and Mg), Li 1 type or 2 or more types of compounds selected from ₂ O, B ₂ O ₃ and MSiO ₃ are contained in less than 5 mol (excluding 0) in terms of the oxide with respect to 100 mol of the main component. Is preferred. This fourth subcomponent has the effect of lowering the firing temperature as a sintering aid and improving the relative dielectric constants εr and Qf in the high frequency band.

The above dielectric ceramic composition according to the present invention has a relative dielectric constant εr ≧ 200, a quality factor Q (= 1 / tan δ, tan δ: dielectric loss tangent) and f at a resonance frequency f derived from the TE ₀₁₁ mode in the GHz band. The characteristic of the absolute value | τεr | ≦ 1000 (ppm / ° C.) of the temperature characteristic τεr of the relative permittivity at −40 to 85 ° C. can be obtained.

  As described above, according to the present invention, by including the oxide of Cr as the first subcomponent and optimizing the composition, a high relative dielectric constant and a high Qf can be obtained in a high frequency band exceeding GHz. In addition, a dielectric ceramic composition having an excellent relative dielectric constant temperature characteristic τεr can be obtained.

Hereinafter, the dielectric ceramic composition of the present invention will be described in more detail.
The dielectric ceramic composition of the present invention includes a main component including a dielectric oxide having a composition represented by (Sr _1-x Ca _x ) _m TiO ₃ and an oxide of Cr as a first subcomponent. The symbols x and m indicating the composition molar ratio in the formula contained in the formula are 0.32 <x <0.42 and 0.965 <m <1.035, and the first subcomponent with respect to 100 mol of the main component is Containing less than 1 mol (excluding 0) in terms of Cr in the oxide.

  In the dielectric ceramic composition of the present invention, in the above composition formula, x is 0.32 <x <0.42. x represents the number of Ca atoms, and the phase transition point of the crystal can be arbitrarily shifted by changing x, that is, the Sr / Ca ratio. Therefore, it is possible to control the relative permittivity εr, Qf and the temperature characteristic τεr of the relative permittivity. When x is 0.32 or less, Qf cannot exceed 4000 GHz, and it becomes difficult to make the absolute value | τεr | of the temperature characteristic of relative dielectric constant at −40 ° C. to 85 ° C. to 1000 ppm / ° C. or less. Further, when x is 0.42 or more, the temperature characteristic τεr of the relative permittivity deteriorates, and the absolute value | τεr | cannot be made 1000 ppm / ° C. or less. The range of x is preferably 0.34 to 0.40, more preferably 0.36 to 0.38.

  In the dielectric ceramic composition of the present invention, m is 0.965 <m <1.035 in the above composition formula. When m is 0.965 or less, a Qf of 4000 GHz or more cannot be obtained, and the specific resistance ρ is greatly reduced. On the other hand, when m is 1.035 or more, sintering does not proceed sufficiently unless the firing temperature is increased, and Qf remains at a value of less than 3000 GHz. The range of m is preferably 0.970 to 1.020, more preferably 0.970 to 1.010.

  The dielectric ceramic composition of the present invention contains a Cr oxide as the first subcomponent. The ratio of the first subcomponent is less than 1 mol (excluding 0) in terms of Cr in the oxide with respect to 100 mol of the main component. This is because when the ratio of the first subcomponent is 1 mol or more, Qf and specific resistance ρ are reduced. The ratio of the first subcomponent is preferably 0.1 to 0.8 mol, more preferably 0.1 to 0.5 mol in terms of Cr in the oxide with respect to 100 mol of the main component.

  The dielectric ceramic composition according to the present invention further includes an oxide of X (where X is one or more elements selected from V, Nb, W, Ta and Mo) as the second subcomponent. It is preferable to have added. The amount of the second subcomponent added is preferably less than 2 mol (excluding 0) in terms of X in the oxide with respect to 100 mol of the main component. This is because when the amount of the second subcomponent added is 2 mol or more, Qf decreases and the specific resistance ρ also decreases. The addition amount of the second subcomponent is preferably 0.1 to 1.5 mol, more preferably 0.1 to 1 mol, in terms of X in the oxide, with respect to 100 mol of the main component.

  The dielectric ceramic composition according to the present invention further includes, as a third subcomponent, an oxide of R (where R is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy). , Ho, Er, Tm, Yb and Lu are preferably added). The amount of the third subcomponent added is less than 2 mol (excluding 0) in terms of R in the oxide with respect to 100 mol of the main component. This is because when the amount of the third subcomponent added is 2 mol or more, Qf and the specific resistance ρ are lowered, and the temperature characteristic τεr of the dielectric constant is deteriorated. The addition amount of the third subcomponent is preferably 0.01 to 1.5 mol, more preferably 0.1 to 1 mol, in terms of R in the oxide, with respect to 100 mol of the main component.

In the dielectric ceramic composition according to the present invention, SiO ₂ , MO (where M is one or more elements selected from Ba, Ca, Sr, and Mg), Li ₂ as a fourth subcomponent. It is preferable to include one or two or more compounds selected from O, B ₂ O ₃ and MSiO ₃ . This fourth subcomponent mainly acts as a sintering aid, but also has an effect of improving Qf.
The addition amount of the fourth subcomponent is preferably less than 5 mol (excluding 0) in terms of the oxide with respect to 100 mol of the main component. When the added amount of the fourth subcomponent exceeds 5 mol, Qf is lowered and the firing temperature needs to be increased. The amount of the fourth subcomponent added is preferably 0.4 to 3 mol, more preferably 1 to 3 mol, per 100 mol of the main component.

According to the composition of the dielectric ceramic composition according to the present invention described above, the raw material of the dielectric ceramic composition of the present invention includes a raw material that constitutes the main component and a raw material that constitutes the first to fourth subcomponents. Used. As raw materials constituting the main component, oxides of Sr, Ca, Ti and / or compounds that become oxides upon firing are used. As a raw material constituting the first subcomponent, a Cr oxide and / or a compound that becomes an oxide by firing is used. As a raw material constituting the second subcomponent, an oxide of X (where X is one or more elements selected from V, Nb, W, Ta and Mo) and / or an oxide by firing One or more single oxides or complex oxides selected from the following compounds are used. As the raw material constituting the third subcomponent, R (wherein R is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) 1 type or 2 or more types of elements selected from 1) and / or 1 type or more of single oxides or composite oxides selected from compounds that become oxides upon firing. As raw materials constituting the fourth subcomponent, SiO ₂ , MO (where M is one or more elements selected from Ba, Ca, Sr and Mg), Li ₂ O, B ₂ O ₃ and One or more compounds selected from MSiO ₃ are used.

  In addition, as a compound which becomes an oxide by baking, carbonate, nitrate, oxalate, an organometallic compound, etc. are mentioned, for example. These compounds and oxides may be used in combination. What is necessary is just to determine content of each compound in a dielectric material so that it may become the composition of the dielectric ceramic composition mentioned above after baking. What is necessary is just to select suitably the average particle diameter of these raw material powders in the range of about 0.01-5.0 micrometers.

These raw material powders of the main component and subcomponent are weighed according to the composition of the dielectric ceramic composition according to the present invention described above, and wet-mixed by, for example, a ball mill. After the slurry is dried, calcination is performed, for example, in the range of 900 to 1350 ° C. for a predetermined time. The atmosphere at this time may be in N ₂ or air. What is necessary is just to select suitably the holding time of calcination in the range of 0.5 to 5.0 hours. After the calcination, the calcined body is pulverized, for example, to an average particle size of about 0.5 to 2.0 μm. For example, a ball mill is used for the pulverization.

  In addition, the timing which adds the raw material powder of a 1st-4th subcomponent is not limited to what was mentioned above. For example, first, only the main component raw material powder is weighed, mixed, calcined and pulverized, and the main component powder obtained after this calcined pulverization is added a predetermined amount of the first to fourth subcomponent raw material powders, You may make it mix.

  The aforementioned pulverized powder is granulated in order to smoothly execute the subsequent molding process. At this time, it is desirable to add a small amount of an appropriate binder such as polyvinyl alcohol (PVA) to the pulverized powder. The particle size of the obtained granules is preferably about 80 to 200 μm. The granulated powder can be pressure-molded at a pressure of 200 to 300 MPa to obtain a molded body having a desired shape.

After removing the binder added during molding by heating and holding before firing, the molded body is heated and held for a predetermined time in a range of 1250 to 1500 ° C., for example, to obtain a sintered body. The atmosphere at this time may be in N ₂ or air. What is necessary is just to set a heating time suitably in the range of 2 to 6 hours. In order to sufficiently bring out the effects of the dielectric ceramic composition of the present invention, it is desirable to fire in the range of 1300 to 1400 ° C.

Through the above steps, the dielectric ceramic composition according to the present invention can be obtained. The dielectric ceramic composition of the present invention has a relative dielectric constant εr at a resonance frequency f derived from the TE ₀₁₁ mode in the GHz band of 200 or more, a Qf of 4000 GHz or more, and a temperature characteristic τεr of the relative dielectric constant at −40 to 85 ° C. Has an absolute value | τεr | of 1000 ppm / ° C. or less. The dielectric ceramic composition according to the present invention having such excellent characteristics is suitable as a material for high frequency, particularly microwave resonators, filters, multilayer capacitors and the like.

  The dielectric ceramic composition of the present invention can be applied to the dielectric powder contained in the composite substrate described above. This powder can be prepared by firing the raw material powder and then pulverizing it. For example, after calcining after mixing the raw material powders weighed to the final composition, adding the additive to the calcined composition and pulverizing it, further firing the pulverized powder, the resulting calcined product Can be obtained by grinding. The calcination and firing may be performed according to ordinary methods. The same applies to pulverization. In addition, as above-mentioned as raw material powder regarding a main component and a 1st-4th subcomponent, an oxide powder can also be used and the compound powder used as an oxide after baking can also be used.

  When obtaining a composite substrate, the content of the dielectric powder is preferably 30 to 70 vol% when the total of the dielectric powder and the resin is 100 vol%. When the amount of dielectric powder is less than 30 vol% (the amount of resin exceeds 70 vol%), the dimensional stability as a substrate is lacking and the relative dielectric constant εr is lowered. That is, the effect of containing dielectric powder is not so much seen. On the other hand, when the amount of the dielectric powder exceeds 70 vol% (the amount of the resin is less than 30 vol%), the fluidity becomes very poor during press molding, and a dense molded product cannot be obtained. As a result, the strength is reduced and water or the like can easily enter, leading to deterioration of electrical characteristics. Further, Qf may be greatly reduced as compared with the case where no dielectric ceramic powder is added. Therefore, the content of the dielectric powder is set to 30 to 70 vol%. The desirable dielectric powder content is 30-50 vol%, and the more desirable dielectric powder content is 35-50 vol%.

As starting materials for producing the dielectric material, SrCO ₃ , CaCO ₃ , TiO ₂ , and first to fourth subcomponent materials as main component materials each having an average particle diameter of 0.1 to 1 μm were prepared. As subcomponent materials, first subcomponent: Cr ₂ O ₃ , second subcomponent: V ₂ O ₅ , third subcomponent: Y ₂ O ₃ , and fourth subcomponent: CaSiO ₃ which are oxides were used. . The fourth subcomponent CaSiO ₃ was obtained by wet mixing SiO ₂ and CaCO ₃ with a ball mill for 16 hours, drying, firing in air at 1330 ° C., and further wet pulverizing with a ball mill for 100 hours. A thing was used.

These raw materials are represented by the composition formula (Sr _1-x Ca _x ) _m TiO ₃ (main component) + Cr ₂ O ₃ (first subcomponent) + V ₂ O ₅ (second subcomponent) + Y ₂ O ₃ (third subcomponent) ) + CaSiO ₃ (fourth subcomponent) were weighed so as to have the compositions shown in Tables 1 to 6 after firing, and then wet mixed by a ball mill for about 16 hours. The slurry was sufficiently dried and then calcined at 1230 ° C. in the air. The obtained calcined body was roughly pulverized in a mortar, then wet pulverized by a ball mill for about 16 hours, and dried to obtain a dielectric ceramic composition (dielectric material). In addition, the number-of-moles of the 1st-4th subcomponent of Table 1-Table 6 is a ratio with respect to 100 mol of main components.

  An appropriate amount of PVA (polyvinyl alcohol) as a binder is added to the dried dielectric material thus obtained and granulated, and a bulk molded body having a diameter of about 12 mm and a thickness of about 6 mm by press molding, and a diameter of about 12 mm. A disk-shaped molded body having a thickness of about 1 mm was produced. These molded bodies were fired in air at 1300 to 1400 ° C. to obtain a sample made of a dielectric ceramic composition. The bulk molded body was processed into a diameter of about 10 mm and a thickness of about 5 mm after firing to obtain a sample made of a dielectric ceramic composition.

Using the obtained dielectric ceramic composition, dielectric characteristics (relative permittivity εr, Qf, temperature characteristic τεr of relative permittivity) and specific resistance ρ were measured.
The measurement of dielectric properties was performed as follows based on the Hakki-Coleman method.
A bulk sample was sandwiched between two metal plates arranged in parallel, and a probe connected to a network analyzer (8510C manufactured by Hured Packard) was fixed to both sides of the sample. A high frequency was oscillated from one probe and frequency characteristics were measured, and a relative dielectric constant εr was obtained from the obtained TE ₀₁₁ mode resonance peak and sample size. Further, the surface resistivity of the metal plate is obtained using a standard sample, the dielectric loss of the metal plate is obtained from this value, and the dielectric loss of the metal plate is removed from the total dielectric loss value to obtain the Qf of the sample. It was. Further, the relative dielectric constant εr at −40 ° C. and 85 ° C. was obtained in the same manner as described above, and the temperature characteristic τεr of the relative dielectric constant between the temperatures was calculated. The evaluation results are shown in Tables 1 to 6.

The specific resistance ρ was measured as follows.
An electrode paste was applied to both sides of the disc-shaped sample after firing. The insulation resistance IR after applying DC100V for 60 seconds at 25 degreeC was measured for this sample using the insulation resistance meter (Advantest R8340A). The specific resistance ρ (Ωcm) was calculated from this measured value and the electrode area and thickness of the disk-shaped sample. The evaluation results are shown in Tables 1 to 6. In Tables 1 to 6, “aE + n” in the column of specific resistance ρ means “a × 10 ^{+ n} ”.

In addition, these samples may also be a method in which SrCO ₃ , CaCO ₃ , and TiO ₂ which are main component materials are first wet mixed, calcined, and then first to fourth subcomponents are added, wet mixed, and fired. Similar characteristics were obtained.

The sample obtained as described above contains ZrO ₂ , BaO, etc. in addition to the components shown in the composition formula from raw materials and pulverized mixing with a ball mill, etc., as long as it does not affect the characteristics of the present invention. It can be mixed.

  As shown in Table 1, when x indicating Ca content is 0.32, Qf is less than 4000, and the temperature characteristic τεr of relative dielectric constant is also about −1500 ppm / ° C. Further, when x is 0.42, the temperature characteristic τεr of the relative dielectric constant is less than −2000 ppm / ° C. From the above results, in the present invention, x is defined as 0.32 <x <0.42. Preferred x is 0.34 to 0.40, and more preferred x is 0.36 to 0.38.

  As shown in Table 2, when m representing the molar ratio (Sr + Ca) / Ti of the main component is 0.965, Qf and specific resistance ρ are low. On the other hand, when m is 1.035, sintering does not proceed sufficiently unless the firing temperature is increased to 1395 ° C. Moreover, even if the firing temperature is increased, Qf decreases to a value of less than 3000. Therefore, in the present invention, m is set to 0.965 <m <1.035. Preferred m is 0.970 to 1.020, and more preferred m is 0.970 to 1.010.

In Table 3, it can be seen that the addition of Cr ₂ O ₃ (first subcomponent) improves the relative permittivity εr and Qf and also improves the temperature characteristic τεr of the relative permittivity. However, when the amount added is 1.00 mol in terms of Cr in the oxide, the Qf is significantly reduced and the specific resistance ρ is not negligible. Therefore, in the present invention, the first subcomponent is less than 1 mol (not including 0) in terms of Cr in the oxide. The addition amount of the first subcomponent is preferably 0.1 to 0.8 mol, more preferably 0.1 to 0.5 mol in terms of Cr in the oxide with respect to 100 mol of the main component.

As shown in Table 4, by adding V ₂ O ₅ (second subcomponent), the firing temperature is lowered, Qf is improved, and the temperature characteristic τεr of the dielectric constant tends to be improved. However, when the addition amount is 2.00 mol in terms of V in the oxide, the Qf is significantly reduced and the specific resistance ρ is not negligible. Therefore, in this invention, the addition amount of a 2nd subcomponent shall be less than 2 mol (0 is not included) in conversion of V (X) in an oxide. The addition amount of the second subcomponent is preferably 0.1 to 1.5 mol, more preferably 0.1 to 1 mol, in terms of V (X) in the oxide, relative to 100 mol of the main component. .

As shown in Table 5, the temperature characteristic τεr of the dielectric constant is improved by adding Y ₂ O ₃ (third subcomponent). However, when the added amount is 2.00 mol in terms of Y in the oxide, the Qf is significantly lowered and the temperature characteristic τεr of the dielectric constant cannot be ignored. In addition, the firing temperature is increased. Therefore, in the present invention, the amount of the third subcomponent added is less than 2 mol (excluding 0) in terms of Y (R) in the oxide with respect to 100 mol of the main component. The addition amount of the third subcomponent is preferably 0.01 to 1.5 mol, more preferably 0.1 to 1 mol, in terms of Y (R) in the oxide, relative to 100 mol of the main component. .

As shown in Table 6, Qf can be improved by adding CaSiO ₃ (fourth subcomponent). Moreover, the addition of CaSiO ₃ (fourth subcomponent) is also effective in reducing the firing temperature. However, when the added amount is 5.00 mol, Qf is lowered and the firing temperature needs to be increased. Therefore, in the present invention, the amount of CaSiO ₃ (fourth subcomponent) is less than 5 mol (not including 0). The amount of the fourth subcomponent is preferably 0.4 to 3 mol, more preferably 1 to 3 mol, relative to 100 mol of the main component.

A dielectric ceramic composition was prepared in the same manner as in Example 1 except that the raw material powder was weighed so as to have the composition shown in Table 7 after firing, and the characteristics such as the dielectric constant εr were measured in the same manner as in Example 1. did. The results are shown in Table 7. Note that the raw material of the first auxiliary component, with MnCO ₃ powder and _Cr 2 _{O 3} powder as a raw material of MnO.

As shown in Table 7, it was confirmed that even when a part of Cr ₂ O ₃ as the first subcomponent was substituted with MnO, the same characteristics as when Cr ₂ O ₃ was added alone were obtained.

  A dielectric ceramic composition was prepared in the same manner as in Example 1 except that the raw material powder was weighed so as to have the composition shown in Table 8 after firing, and the characteristics such as the dielectric constant εr were measured in the same manner as in Example 1. did. The results are shown in Table 8. In addition, the oxide powder of each element was used for the raw material of the 2nd subcomponent.

  As shown in Table 8, it was confirmed that even when the second subcomponent other than V was used, the same characteristics as when V was used were obtained.

  A dielectric ceramic composition was prepared in the same manner as in Example 1 except that the raw material powder was weighed so as to have the composition shown in Table 9 after firing, and the characteristics such as dielectric constant εr were measured in the same manner as in Example 1. did. The results are shown in Table 8. In addition, the oxide powder of each element was used for the raw material of the 3rd subcomponent.

  As shown in Table 9, it was confirmed that the same effect as Y was obtained even when the third subcomponent other than Y was used.

A dielectric ceramic composition was prepared in the same manner as in Example 1 except that the raw material powder was weighed so as to have the composition shown in Table 10 after firing, and the characteristics such as the dielectric constant εr were measured in the same manner as in Example 1. did. The results are shown in Table 10. (Ba, Ca) SiO ₃ , (Sr, Ca) SiO ₃ and (Mg, Ca) SiO ₃ are wet-mixed for 16 hours with a ball mill using SiO ₂ and MCO ₃ (M = Ba, Sr, Ca, Mg). Then, after drying, the product obtained by firing in air at 1330 ° C. and wet pulverizing with a ball mill for 100 hours was used.

As shown in Table 10, it was confirmed that the same characteristics as CaSiO ₃ were obtained even when the fourth subcomponent other than CaSiO ₃ was used.

Claims (6)

A main component including a dielectric oxide having a composition represented by (Sr _1-x Ca _x ) _m TiO ₃ and an oxide of Cr as a first subcomponent;
The symbols x and m indicating the composition molar ratio in the formula contained in the main component are 0.32 <x <0.42, 0.965 <m <1.035,
The dielectric ceramic composition, wherein the first subcomponent is contained in an amount of less than 1 mol (excluding 0) in terms of Cr in the oxide with respect to 100 mol of the main component.   As a second subcomponent, an oxide of X (where X is one or more elements selected from V, Nb, W, Ta and Mo) is added to 100 mol of the main component. The dielectric ceramic composition according to claim 1, which is contained in an amount of less than 2 mol (excluding 0) in terms of X in the inside.   As the third subcomponent, R (where R is selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) The dielectric according to claim 1 or 2, comprising an oxide of a seed or two or more elements) in an amount of less than 2 mol (excluding 0) in terms of R in the oxide with respect to 100 mol of the main component. Porcelain composition. As the fourth subcomponent, selected from SiO ₂ , MO (where M is one or more elements selected from Ba, Ca, Sr and Mg), Li ₂ O, B ₂ O ₃ and MSiO _3. The dielectric ceramic according to any one of claims 1 to 3, wherein one or two or more compounds are contained in an amount of less than 5 mol (excluding 0) in terms of the oxide with respect to 100 mol of the main component. Composition.   5. The dielectric ceramic composition according to claim 1, wherein a part of the oxide of Cr as the first subcomponent is substituted with an oxide of Mn. At the resonance frequency f derived from the TE ₀₁₁ mode in the GHz band, the relative permittivity εr ≧ 200, the product of the quality factor Q (= 1 / tan δ, tan δ: dielectric loss tangent) and f, Qf ≧ 4000 (GHz), −40 to 40 6. The dielectric ceramic composition according to claim 1, wherein the absolute value of the temperature characteristic τεr of relative dielectric constant at 85 ° C. | τεr | ≦ 1000 (ppm / ° C.).