JP2006008484A - Low-temperature firing dielectric porcelain composition and dielectric article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a low-temperature firing dielectric porcelain composition consisting of Bi-Zn-Nb system oxides which is capable of being fired at a low temperature and of gaining a high, unloading Q value while holding a sufficient specific inductive capacity, and to provide a dielectric article using the same. <P>SOLUTION: This low-temperature firing dielectric porcelain composition contains Bi, an M as a divalent metal element (for example, Zn), at least Nb selected between Nb and Ta, and O, and furthermore has the expression of the formula: xBiO<SB>3/2</SB>-yMO-z(Nb<SB>a</SB>Ta<SB>b</SB>)O<SB>5/2</SB>satisfying the followings: 0.455≤x≤0.545; 0.155≤y<0.19; 0.305≤z≤0.362; 0<a≤1 and 0≤b<1. The dielectric article 1 is provided with dielectric porcelain parts of 111,112 and 113 comprising this low-temperature firing dielectric porcelain composition and with conductor parts 121, 122 and 123 which are fired simultaneously on the surface and/or the mass of this dielectric porcelain part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a low-temperature fired dielectric ceramic composition and a dielectric component. More specifically, the present invention relates to a low-temperature fired dielectric ceramic composition and a dielectric component that are particularly excellent in a no-load quality factor.

  In recent years, with the increase in the amount of communication information, various communication systems using microwave bands and millimeter wave bands such as automobile communication, satellite communication, satellite broadcasting, etc. are rapidly developing. It is increasingly demanded. In recent years, there has been a demand for such a dielectric ceramic material that is a low-temperature fired dielectric ceramic material that can be fired simultaneously with a low melting point conductor and that can exhibit excellent dielectric properties.

So far, BaO—RE ₂ O ₃ —TiO ₂ (RE: rare earth element) -based material (dielectric constant of about 70) is known as a material having a high dielectric constant in the microwave band. However, this material needs to be fired at a high temperature of 1300 ° C. or higher, and cannot be fired simultaneously with a conductor layer made of a low melting point metal such as copper and silver. On the other hand, Bi—Zn—Nb-based oxides and Bi—Ca—Nb-based oxides are known as materials that can obtain the same dielectric constant and can be fired at a low temperature of 1000 ° C. or lower.
Among these, the former Bi—Ca—Nb-based oxide is disclosed in, for example, the following Patent Documents 1, 2, and 3. Further, as a development type of the composition system, a composition in which a part of Ca is substituted with Zn (the following Patent Documents 4 and 5), a composition in which a part of Ca is replaced with Ba (the following Patent Document 6), and a part of Ca A composition in which is replaced with Sr (the following Patent Document 7), a composition in which a part of Ca is replaced with Mg (the following Patent Document 8), a composition in which a part of Nb is replaced with Ta (the following Patent Document 9), etc. are known. ing.
On the other hand, a Bi—Zn—Nb-based oxide is disclosed in Patent Document 10 below.

JP-A-5-225826 JP-A-7-37425 JP 7-201224 A JP-A-5-242728 JP-A-6-196020 JP 7-57538 A JP-A-7-57539 JP-A-7-57540 JP 7-296638 A JP-A-4-285046

However, as shown in Patent Document 10 above, although a range showing an excellent relative dielectric constant of 83 to 133 is recognized, the maximum no-load quality factor (hereinafter also simply referred to as “no-load Q value”) The value is as low as 310. For this reason, the use as a material for electronic components is difficult.
The present invention solves the above-mentioned problems, and is a low-temperature fired dielectric ceramic made of a Bi-Zn-Nb-based oxide that can be fired at a low temperature and can obtain a high unloaded Q value while maintaining a sufficient dielectric constant. An object is to provide a composition and a dielectric component using the composition.

The present inventors have found that in the Bi—Zn—Nb-based oxide, there is a region where a high unloaded Q value can be obtained while maintaining a relative dielectric constant at a conventional level in an extremely narrow composition range. The present invention has been completed.
That is, the present invention is as follows.
(1) contains Bi, M which is a divalent metal element, at least Nb of Nb and Ta, and O, and
When expressed as _{xBiO 3/2 -yMO-z (Nb a} Ta b) O 5/2, said x, said y, the z, cold said a and the b is to satisfy the respective following relationship Firing dielectric ceramic composition.
0.455 ≦ x ≦ 0.545
0.155 ≦ y <0.19
0.305 ≦ z ≦ 0.362
0 <a ≦ 1
0 ≦ b <1
(2) The low-temperature fired dielectric ceramic composition according to (1), wherein M is Zn.
(3) The x, y, and z are 0.495 ≦ x ≦ 0.505, 0.166 ≦ y ≦ 0.168, and 0.332 ≦ z ≦ 0.334. Low-temperature fired dielectric ceramic composition.
(4) The low-temperature fired dielectric ceramic composition according to any one of (1) to (3), wherein the relative dielectric constant is 60 or more and the no-load quality factor is 350 or more.
(5) The low-temperature fired dielectric ceramic composition according to any one of the above (1) to (4), which has an orthorhombic pyrochlore structure.
(6) A dielectric ceramic part made of the low-temperature fired dielectric ceramic composition according to any one of the above (1) to (5), and co-fired on the surface and / or inside of the dielectric ceramic part A dielectric component comprising a conductor portion.
(7) The dielectric component according to (6), wherein the conductor portion is made of a conductor metal containing at least one of Cu, Ag, and Au as a main component.

According to the low-temperature fired dielectric ceramic composition of the present invention, an unloaded Q value of 350 or more can be obtained while maintaining a relative dielectric constant of 60 or more at a conventional level.
When M is Zn, an unloaded Q value of 350 or more can be obtained while maintaining a relative dielectric constant of 60 or more at a conventional level.
When each of x, y, and z is within a predetermined range, the relative dielectric constant is 70, and a high no-load Q value of 900 or more can be obtained.
When the relative dielectric constant is 60 or more and the no-load quality factor is 350 or more, an electronic component having excellent dielectric characteristics can be obtained.
In the case of having an orthorhombic pyrochlore structure, the relative dielectric constant is 70, and a high unloaded Q value of 900 or more can be obtained.
According to the dielectric component of the present invention, it is possible to obtain an electronic component having excellent dielectric characteristics while being provided with a co-fired conductor portion.

Hereinafter, the present invention will be described in detail.
[1] Low-temperature fired dielectric ceramic composition The low-temperature fired dielectric ceramic composition of the present invention contains Bi, a divalent metal element M, at least Nb and Nb of Nb and Ta, and O. _and, when expressed as _{xBiO 3/2 -yMO-z (Nb a} Ta b) O 5/2, x, y, z, each of a and b, characterized in that a predetermined relationship.

  The “M” is a divalent metal element. That is, examples of M include Zn, Cr, Co, Ni, Cu, Mg, Ca, Sr, and Ba, which are metal elements that can take a divalent oxidation number. Among these, Zn, Ni, Ca and Sr are preferable, and Zn is particularly preferable. These M may use only 1 type and may use 2 or more types together.

The “x” represents a molar ratio of Bi (that is, BiO _3/2 ) and satisfies x + y + z = 1. Furthermore, x satisfies 0.455 ≦ x ≦ 0.545, preferably 0.485 ≦ x ≦ 0.530, more preferably 0.485 ≦ x ≦ 0.505, and still more preferably 0.495 ≦ x ≦ 0.545. 0.505. When x is less than 0.455, the no-load Q value tends to decrease. On the other hand, when it exceeds 0.54, the no-load Q value tends to decrease.

  The “y” represents a molar ratio of M (that is, MO) and satisfies x + y + z = 1. Furthermore, y satisfies 0.155 ≦ y ≦ 0.19, preferably 0.155 ≦ y ≦ 0.185, more preferably 0.155 ≦ y ≦ 0.180, and further preferably 0.166 ≦ y ≦ 0.1. 0.168. If y is less than 0.155, the no-load Q value tends to decrease. On the other hand, when it exceeds 0.19, the no-load Q value tends to decrease.

The “z” represents the total {ie, (Nb _a Ta _b ) O _5/2 } molar ratio of Nb and Ta, and satisfies x + y + z = 1. Furthermore, z satisfies 0.305 ≦ z ≦ 0.362, preferably 0.310 ≦ z ≦ 0.355, more preferably 0.325 ≦ z ≦ 0.345, still more preferably 0.332 ≦ z ≦ 0.3. 0.334. If z is less than 0.305, the unloaded Q value tends to decrease. On the other hand, when it exceeds 0.362, the no-load Q value tends to decrease.

Each preferable range of said x, y, and z can be set as each combination. That is, for example, 0.485 ≦ x ≦ 0.530, 0.155 ≦ y ≦ 0.185, and 0.310 ≦ z ≦ 0.355. If it is this range, a no-load Q value can be 350-1100, keeping a dielectric constant in the range of 65-85.
Furthermore, these x, y, and z can be set to 0.485 ≦ x ≦ 0.505, 0.155 ≦ y ≦ 0.180, and 0.325 ≦ z ≦ 0.345. If it is this range, a no-load Q value can be 700-1100, keeping a dielectric constant in the range of 65-80.
In particular, by setting 0.495 ≦ x ≦ 0.505, 0.166 ≦ y ≦ 0.168, and 0.332 ≦ z ≦ 0.334, the relative dielectric constant is maintained in the range of 70 to 80. However, the unloaded Q value can be set to 1000 to 1100.

Among these combinations of x, y and z, the ranges of 0.495 ≦ x ≦ 0.505, 0.166 ≦ y ≦ 0.168, and 0.332 ≦ z ≦ 0.334 are particularly unique. Therefore, it is an extremely narrow composition range where the unloaded Q value increases. The cause of the specific increase in the unloaded Q value is not clear, but since the composition is a composition close to A ₂ B ₂ O ₇ , an orthorhombic pyrochlore structure is formed in this range. It is possible. However, the entirety of the low-temperature fired dielectric ceramic composition may have an orthorhombic pyrochlore structure, or only a part may have an orthorhombic pyrochlore structure. The case where only a part has an orthorhombic pyrochlore structure is, for example, a case where a subphase is recognized in addition to the pyrochlore structure.

The above “a” represents the molar ratio of Nb to the total amount of Nb and Ta, and satisfies a + b = 1. Furthermore, a satisfies 0 <a ≦ 1, preferably 0.40 ≦ a ≦ 1.00, and more preferably 0.43 ≦ x ≦ 1. When a is 0, the relative permittivity tends to decrease.
The “b” represents the molar ratio of Ta to the total amount of Nb and Ta, and satisfies a + b = 1. Furthermore, b satisfies 0 ≦ a <1, preferably 0 ≦ b ≦ 0.60, and more preferably 0 ≦ b ≦ 0.57. When b is 1, the relative permittivity tends to decrease.

Moreover, each preferable range of these a and b can be made into each combination in addition to each preferable range of said x, y, and z. That is, for example, 0.485 ≦ x ≦ 0.530, 0.155 ≦ y ≦ 0.185, 0.310 ≦ z ≦ 0.355, 0.40 ≦ a ≦ 1.00, and 0 ≦ b ≦ It can be 0.60. If it is this range, a no-load Q value can be 350-1100, keeping a dielectric constant in the range of 65-85.
Furthermore, 0.485 ≦ x ≦ 0.505, 0.155 ≦ y ≦ 0.180, 0.325 ≦ z ≦ 0.345, 0.43 ≦ x ≦ 1, and 0 ≦ b ≦ 0.57 can do. If it is this range, a no-load Q value can be 700-1100, keeping a dielectric constant in the range of 65-80.
In particular, 0.495 ≦ x ≦ 0.505, 0.166 ≦ y ≦ 0.168, 0.332 ≦ z ≦ 0.334, 0.43 ≦ x ≦ 1, and 0 ≦ b ≦ 0.57. Thus, the no-load Q value can be set to 1000 to 1100 while keeping the relative dielectric constant in the range of 70 to 80.

The firing temperature (baked temperature) of the low-temperature dielectric ceramic composition of the present invention is not particularly limited, but is usually 850 to 1000 ° C. Furthermore, this baking temperature can be 850-980 degreeC, and can also be 850-960 degreeC especially.
The firing atmosphere is not particularly limited, and can be appropriately selected depending on the characteristics of the conductor metal constituting the conductor portion described later. That is, for example, when a conductive metal having high oxidation resistance is used, it can be fired in an oxidizing atmosphere such as an air atmosphere. On the other hand, when a conductor metal having low oxidation resistance such as copper is used, it can be fired in an inert atmosphere and / or a reducing atmosphere.

[2] Dielectric Part The dielectric part of the present invention includes a dielectric ceramic part made of the low-temperature fired dielectric ceramic composition of the present invention, and a conductor part disposed on the surface of the dielectric ceramic part by simultaneous firing. It is characterized by providing.
The dielectric ceramic part is not particularly limited except that it is made of the low-temperature fired dielectric ceramic composition of the present invention. That is, for example, in the case of an LC filter, the shape is a rectangular parallelepiped shape in which dielectric ceramic parts (for example, 111, 112 and 113 in FIG. 1) formed into a plate shape are integrally fired. It can be. Moreover, when aiming at a board | substrate, it can be set as various plate-shaped shapes. Furthermore, when the antenna is used, various shapes such as a plate shape and a rectangular parallelepiped shape can be used.

The “conductor portion” is a conductor that is simultaneously fired on the surface and / or inside the dielectric ceramic portion of the present dielectric component. The conductor metal constituting the conductor portion is not particularly limited, and a metal that can exhibit conductivity in a dielectric component, an alloy thereof, and the like can be used. Examples of such conductive metals include Ag, Cu, Au, and the like, and alloys thereof. That is, for example, the conductor part can contain 80% by mass or more (more preferably 90% by mass or more and 100% by mass) of Ag when the entire conductor part is 100% by mass.
When these metals are fired at a high temperature exceeding 1000 ° C., it may be difficult to obtain a desired wiring shape, but the low-temperature dielectric ceramic composition of the present invention can be fired at a low temperature of 1000 ° C. or less. Therefore, simultaneous firing can be performed using these metals as conductor metals.

The application of the dielectric component of the present invention is not particularly limited, and can be used as various electronic components used in the microwave band and the millimeter wave band. Examples of the various electronic parts include individual parts such as filters, duplexers, resonators, LC devices, couplers, diplexers, diodes, dielectric antennas, and ceramic capacitors. Furthermore, it includes at least one of a general-purpose board, a board such as a functional board in which various functional parts are embedded (LTCC multilayer device, etc.), a package such as MPU and SAW, and these individual parts, boards, and packages. Examples include modules. In addition, these electronic components include mobile communication devices, mobile communication base station devices, satellite communication devices, satellite communication base station devices, satellite broadcast devices that use various microwave band and / or millimeter wave band radio waves, It can be used for a wireless LAN device, a Bluetooth (registered trademark) device, and the like.
Since this dielectric component can be fired at a low temperature, has a high dielectric constant, and has a high unloaded Q value, among these, it is particularly suitable as an LC filter and an antenna.

Hereinafter, the present invention will be described specifically by way of examples.
(1) Production of low-temperature fired dielectric ceramic composition Commercially available Bi ₂ O ₃ powder (purity; 98.5%), ZnO powder (purity; 99.8%), Nb ₂ O ₅ powder (purity; 99. 5%) and Ta ₂ O ₅ powder (purity; 99.5%), and each of the above “x”, “y”, “z”, “a” and “b” has the values shown in Table 1. Weighed as follows.
Thereafter, each powder was wet-mixed using ethanol as a medium. Next, the obtained mixed powder was calcined at 800 ° C. for 2 hours in an air atmosphere. Thereafter, a dispersant, a binder and ethanol were added to the calcined product, and pulverized using a ball mill to form a slurry. Next, the obtained slurry was dried and granulated. Thereafter, it was molded into a cylindrical shape by uniaxial pressing at 20 MPa using a φ19 mm mold. Next, CIP (cold isostatic isostatic pressing) treatment was performed at a pressure of 150 MPa, and the obtained molded body was fired at 900 to 1000 ° C. shown in Table 1 for 2 hours in an air atmosphere. Porcelain of -18 (Experimental Examples 1-7 and 12-18, Comparative Examples 8-11) was obtained.

表１中の「＊」は本発明の範囲外であることを表す。

“*” In Table 1 indicates that it is outside the scope of the present invention.

(2) Evaluation of dielectric characteristics Both end faces of each cylindrical porcelain obtained in (1) above were polished. Then, the dielectric constant, the no-load Q value, and the temperature change rate (τ _f ) at a measurement frequency of 2 to 5 GHz were measured for each polished porcelain by a parallel conductor plate type dielectric resonator method. The temperature change rate was calculated by measuring the resonance frequency at 25 ° C. and 80 ° C. and using the value at 25 ° C. as a reference. The results are also shown in Table 1.

(3) X-ray diffraction measurement of the low-temperature fired dielectric ceramic composition of Experimental Example 1 X-ray diffraction measurement of the calcined powder used in the manufacture of Experimental Example 1 was performed. A graph of the obtained X-ray diffraction measurement is shown in FIG.

(4) Effect of Example According to the results of Table 1, from Comparative Examples 8 to 11, which cannot be fired at 1000 ° C. (Experimental Example 11), the resonance is weak and almost no dielectric properties can be obtained. It can be seen that there is a case where a thing (experimental example 8) and a dielectric characteristic can be obtained, but an unloaded Q value is 250 or less and it is difficult to use as an electronic component.

  On the other hand, in Experimental Examples 1 to 7 which are products of the present invention, it can be seen that all can be fired at a low temperature of 1000 ° C. or lower. Further, even when firing at this low temperature, it can be seen that a high value of 370 or more is obtained for the unloaded Q value while obtaining an excellent relative dielectric constant of 75 or more. In particular, in Experimental Example 5, the dielectric constant is 77 and the unloaded Q value is 770, and in Experimental Example 7, the dielectric constant is 78 and the unloaded Q value is 740. Furthermore, in Experimental Example 1, while maintaining a high value of the relative dielectric constant of 77, the unloaded Q value is 1020 that is specifically higher than the other experimental examples. It is considered that the particularly excellent dielectric characteristics are obtained in Experimental Example 1 because an orthorhombic pyrochlore structure is formed.

  Experimental Examples 12 to 18 are examples of compositions containing both Nb and Ta. Also in these experimental examples, it can be seen that a high value of 370 or more is obtained for the no-load Q value while ensuring a relative dielectric constant of 70 or more except for Experimental Example 14. In particular, the dielectric constant is 72 and the unloaded Q value is 780 in Experimental Example 16, and the dielectric constant is 70 and the unloaded Q value is 780 in Experimental Example 18. Furthermore, in Experimental Example 12, while the relative dielectric constant is as high as 71, the unloaded Q value is 1040 that is specifically higher than the other experimental examples. Also in this experimental example 12, it is considered that the particularly excellent dielectric characteristics are obtained because the orthorhombic pyrochlore structure is formed.

(5) Manufacture of dielectric parts (LC filter) The case where this low-temperature firing dielectric ceramic composition is used as an LC filter will be described below.
The same slurry as that used in the granulation of Experimental Example 1 in Table 1 in (1) above was defoamed and then formed into a green sheet (thickness 250 μm) using the doctor blade method. Next, an unsintered conductor part was printed on each surface of three of the obtained green sheets using a conductor part forming silver paste.
Thereafter, the obtained green sheet on which the three unfired conductor portions were formed was laminated under pressure and heating under conditions of a temperature of 100 ° C. and a pressure of 100 kgf / cm 2. Next, the obtained laminate was cut and then fired at 925 ° C. for 2 hours in the atmosphere to obtain a dielectric component 1 (LC filter) shown as an exploded perspective view in FIG.
The dielectric component 1 includes dielectric ceramic parts 111, 112, and 113 and conductor parts 121, 122, and 123. These are integrally fired integrally. That is, although FIG. 1 is shown as an exploded perspective view, in practice, the dielectric ceramic parts 111, 112 and 113 and the conductor parts 121, 122 and 123 in FIG. It has become.

  The present invention can be used as various electronic components used in the microwave band and the millimeter wave band. These various electronic components can be used as various electronic components used in the microwave band and the millimeter wave band. Examples of the various electronic components include individual components such as filters (LC filters, etc.), duplexers, resonators, LC devices, couplers, diplexers, diodes, dielectric antennas, and ceramic capacitors. Furthermore, it includes at least one of a general-purpose board, a board such as a functional board in which various functional parts are embedded (LTCC multilayer device, etc.), a package such as MPU and SAW, and these individual parts, boards, and packages. Examples include modules. In addition, these electronic components include mobile communication devices, mobile communication base station devices, satellite communication devices, satellite communication base station devices, satellite broadcast devices that use various microwave band and / or millimeter wave band radio waves, It can be used for a wireless LAN device, a Bluetooth (registered trademark) device, and the like.

It is a disassembled perspective view of LC filter which is an example of the dielectric component of this invention. 6 is a graph showing the results of X diffraction measurement of the low-temperature fired dielectric ceramic composition of Experimental Example 1.

Explanation of symbols

  1; Dielectric parts (LC filters), 111, 112 and 113; Dielectric ceramic parts, 121, 122 and 123; Conductor parts.

Claims (7)

Bi, M which is a divalent metal element, and at least Nb of Nb and Ta, and
When expressed as _{xBiO 3/2 -yMO-z (Nb a} Ta b) O 5/2, said x, said y, the z, cold said a and the b is to satisfy the respective following relationship Firing dielectric ceramic composition.
0.455 ≦ x ≦ 0.545
0.155 ≦ y <0.19
0.305 ≦ z ≦ 0.362
0 <a ≦ 1
0 ≦ b <1   The low-temperature fired dielectric ceramic composition according to claim 1, wherein M is Zn.   3. The low-temperature firing according to claim 2, wherein each of x, y, and z is 0.495 ≦ x ≦ 0.505, 0.166 ≦ y ≦ 0.168, and 0.332 ≦ z ≦ 0.334. Dielectric ceramic composition.   The low-temperature fired dielectric ceramic composition according to any one of claims 1 to 3, wherein the relative dielectric constant is 60 or more and the no-load quality factor is 350 or more.   The low-temperature-fired dielectric ceramic composition according to any one of claims 1 to 4, having an orthorhombic pyrochlore structure.   A dielectric ceramic part comprising the low-temperature fired dielectric ceramic composition according to any one of claims 1 to 5, and a conductor part simultaneously fired on the surface and / or inside of the dielectric ceramic part. Characteristic dielectric parts.   The dielectric component according to claim 6, wherein the conductor portion is made of a conductor metal containing at least one of Cu, Ag, and Au as a main component.

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