JPH1134231A - Composite laminated dielectric ceramic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a small-sized composite laminated ceramic part capable of realizing a composite high frequency laminated device and having high capacity and high reliability by laminating two or more dielectric layers constituted of dielectric ceramic compsns. consisting of specific materials different in specific dielectric constant and a conductor layer based on silver or the like. SOLUTION: A composite laminated ceramic part is constituted by laminating two or more dielectric layers constituted of dielectric ceramic compsns. based on bismuth oxide and niobium oxide different in specific dielectric constant and a conductor layer based on silver or copper. As a starting raw material, Bi2 O3 , Nb2 O5 , CaCO3 , ZnO, V2 O5 and CuO being chemically pure are used. As a composite laminated type microwave device, a dielectric resonator having a structure wherein a strip line conductor 4 and a shield conductor 3 are built in two dielectric layers 1, 2 different in compsn. ratio is obtained. A shield conductor is provided not only to the upper and lower end parts of the resonator but also to the interface of two dielectric layers 1, 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite laminated dielectric ceramic component applied to various filters and resonators used in a high frequency range.

[0002]

2. Description of the Related Art In recent years, with the development of communication using electromagnetic waves in the microwave region such as mobile phones and satellite broadcasting, demands for miniaturization of terminal equipment have been increasing. In order to reduce the size of a terminal device, it is necessary to reduce the size of individual components constituting the device. In these devices, dielectric porcelain is incorporated as various filters and resonators. When using the same resonance mode, the size of these resonance devices is the relative dielectric constant (ε) of the dielectric material used.
Since it is inversely proportional to the square root of r), a material having a high relative dielectric constant is required to produce a small-sized resonant device. Further, other characteristics required for the dielectric material for the dielectric porcelain are a low loss in the microwave region, that is, a high Q value, and a small temperature coefficient (τf) of the resonance frequency. Here, the Q value refers to the reciprocal of the dielectric loss tan δ.

In addition, a conductor and a dielectric porcelain have a laminated structure,
Attempts have been made to make the resonance device smaller and more sophisticated. When the conductor is used in a high frequency region such as a microwave, the conductor needs to have high conductivity.
g or their alloys. Also,
When the dielectric porcelain has a laminated structure, it must be fired at the same time as the conductor metal, and therefore must be densely sintered under firing conditions in which the conductor metal does not melt and oxidize.

That is, at a low temperature below the melting point (1083 ° C. for Cu, 961 ° C. for Ag) of the conductive metal used,
Further, when Cu is used for the electrode, firing at a low oxygen partial pressure is required. The microwave dielectric ceramic that can be sintered at a low _{temperature, Bi 2 O 3 -Nb 2 O} 5 system Hei 5-74225
In _{JP, Bi 2 O 3 -CaO-Nb} 2 O 5 system Hei 5-
No. 242728 discloses Bi ₂ O ₃ —CaO—ZnO—C.
uO-Nb ₂ O ₅ system is proposed in JP-A-6-196020. At present, using these dielectric porcelains, a small laminated resonance device with a built-in strip line using silver as a conductor has been realized and used as a high-frequency resonance device for mobile phones.

[0005] By the way, there are various transmission / reception systems for portable telephones in Japan regardless of the world. In recent years, mobile phones capable of transmitting and receiving a plurality of systems with one terminal have been developed. In this case, since the transmission and reception frequencies used in each system are different, the number of high-frequency resonance heights inevitably increases, and the volume and weight of the mobile terminal increase. Therefore, there is a need for a small composite high-frequency resonance device that can handle a plurality of transmission and reception frequencies with one device.

[0006]

However, when a laminated resonance device corresponding to a plurality of frequencies is formed on a single dielectric, the resonance frequency is determined by the relative permittivity of the dielectric and the length and shape of the strip line. However, the available resonance frequencies are limited.

Therefore, by laminating a plurality of dielectric layers having different relative dielectric constants and forming a strip line on each layer, a small high-frequency resonance device having a plurality of resonance frequencies over a wide range can be manufactured by one device. Can be.

However, in general, when dielectric ceramics having different compositions are stacked and fired, the firing shrinkage behavior and the coefficient of thermal expansion are greatly different from each other, so that defects such as delamination, warpage, and cracks occur during the firing process. Likely to happen. Therefore, it is desirable that the dielectric ceramics forming the respective layers have the same composition series. That is, it is desirable to use a dielectric porcelain in which the relative permittivity can be largely changed by a difference in the composition ratio even though the composition series is the same.

Further, in order to realize a high-performance composite high-frequency resonance device, it is necessary that the dielectric ceramic of each layer has excellent electric characteristics, that is, a large Q value and a small τf. is there.

Further, in order to simultaneously sinter with a conductor layer having silver or copper as a main component having high conductivity, it is necessary to sinter densely under sintering conditions in which the conductor metal is not dissolved and oxidized. In particular, when silver having a purity of 100% is used for an electrode, the melting point of silver is 961 ° C., so that firing must be performed at a low temperature of 950 ° C. or less, and when copper is used for an electrode, firing must be performed at a low oxygen partial pressure.

An object of the present invention is to provide a compact, high-performance, high-reliability composite laminated porcelain component for high frequencies that can realize a composite high-frequency laminated device that handles a plurality of frequencies.

[0012]

According to the present invention, there is provided a dielectric ceramic composition comprising bismuth oxide and niobium oxide as main components and having at least two dielectric layers having different relative dielectric constants.
It is a composite laminated dielectric porcelain part in which conductor layers mainly composed of silver or copper are laminated. By changing the constituent elements and the composition ratio of the dielectric ceramic composition constituting the composite laminated dielectric ceramic part, the relative dielectric constant εr can be relatively easily changed without significantly impairing Q and τf. It is. Therefore, if a resonance circuit is formed in each of the dielectric layers having different relative dielectric constants, a composite high-frequency multilayer device that can handle a wide frequency band can be realized with one element. In addition, this dielectric ceramic composition has a small difference in shrinkage behavior and thermal expansion coefficient due to a difference in composition ratio, and can suppress generation of defects such as delamination, warpage, and cracks due to integral firing.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a dielectric ceramic composition composed of a dielectric ceramic composition containing bismuth oxide and niobium oxide as main components and having different dielectric constants. And a conductor layer mainly composed of silver or copper. With this configuration, a composite laminated dielectric porcelain component including two or more dielectric layers having different relative dielectric constants εr and a conductive layer containing silver having high conductivity as a main component is provided.
It can be obtained without delamination or defects such as cracks in each dielectric layer by integral firing.

According to a second aspect of the present invention, the dielectric ceramic composition constituting all the dielectric layers has a relative dielectric constant εr of 35 or more, a Qf product of 1000 GHz or more, and an absolute temperature coefficient of the resonance frequency. The value | τf | is limited to 50 ppm / ° C. or less, whereby a small-sized and high-performance composite laminated ceramic part can be obtained.

Hereinafter, a composite laminated ceramic component according to an embodiment of the present invention will be described in detail.

The starting material is Bi ₂ which is chemically high in purity.
O ₃ , Nb ₂ O ₅ , CaCO ₃ , ZnO, V ₂ O ₅ and Cu
O was used. After the purity of the raw material was corrected, the composition was weighed so as to have various values shown in the column of composition in (Table 1). The addition amounts of the additive V and Cu components are determined by the molar ratio V to the main component Bi, Nb, Ca and Zn components, respectively.
/ (Bi + Nb + Ca + Zn), Cu / (Bi + Nb +
Ca + Zn).

[0017]

[Table 1]

These powders are put into a polyethylene ball mill, and a ball of stabilized zirconia and pure water are added.
Mix for 7 hours. After mixing, the slurry was dried, placed in an alumina crucible, and calcined at 750 to 950 ° C for 2 to 5 hours. After the calcined body was crushed by a raikai machine, it was crushed by the above-mentioned ball mill for 17 hours and dried to obtain a raw material powder. 6% by weight of a 5% aqueous solution of polyvinyl alcohol as a binder was added to the powder, mixed, and then granulated through a 32 mesh sieve, and pressed at 100 MPa into a column having a diameter of 13 mm and a thickness of about 5 mm. The molded body was heated at 600 ° C. for 2 hours to incinerate the binder, placed in a magnesia container, covered, and fired at 850 to 1100 ° C. in air for 2 to 4 hours. The dielectric properties of the sintered body fired at the temperature at which the density was maximized were measured by microwave. The resonance frequency and the Q value were obtained by a dielectric resonator method. The relative permittivity εr was calculated from the dimensions of the sintered body and the resonance frequency. The resonance frequency is
It was 2-5 GHz. -25 ° C, 20 ° C and 85 ° C
Was measured, and its temperature coefficient τf was calculated by the least squares method. The coefficient of thermal expansion α of each sintered body was measured by TMA. The results are shown in (Table 2).

[0019]

[Table 2]

As shown in Table 2, each of the dielectric ceramic compositions is densely sintered at a low temperature of 925 ° C. or less, and the product of the measurement frequency f and the Q value is 1800 or more, and It shows excellent characteristics when the absolute value of τf is 30 ppm / ° C. or less, and the relative dielectric constant varies between 43 and 101 depending on the composition ratio. In addition, the coefficient of thermal expansion was small depending on the difference in composition, and in each case was 76 to 92 × 10 ⁻⁷ / ° C. It should be noted that there was almost no change in firing temperature and characteristics even in firing in nitrogen.

Next, several compositions are selected from (Table 1),
Composite laminates were prepared in the combinations shown in Table 3 and evaluated.

[0022]

[Table 3]

As a composite laminated microwave device,
A dielectric resonator having a structure in which a stripline conductor and a shield conductor were built in two dielectric layers 1 and 2 having different composition ratios was manufactured. The shield conductor was provided not only at the upper and lower ends of the resonator but also at the interface between the two dielectric layers 1 and 2. FIG. 1 shows a cross-sectional view thereof. Hereinafter, the manufacturing method will be described.

First, a slurry obtained by adding a polyvinyl butyral resin as an organic binder, dibutyl phthalate as a plasticizer, and butyl acetate as a solvent to the raw material powders of the respective compositions shown in (Table 2), and mixing the resulting mixture with a ball mill, was used as a doctor. Green sheets were formed by the blade method. The conductive metal was kneaded with the vehicle to form a paste. The conductor is Cu
In this case, a CuO paste was used. FIG. 2 shows a conductor printing pattern of the element. The length of the strip line 3 in FIG. 2A is 13 mm.

Next, the printing / lamination process will be described. First, a green sheet of composition A is laminated to a desired thickness, and FIG.
The shield conductor pattern 3 of FIG.
Printing is performed by a well-known screen printing method using an O paste and drying is performed. Further, a plurality of sheets of the composition A are laminated on the upper surface, and next, the strip line conductor pattern 4 shown in FIG.
Print.

In the same process, the sheet of composition A, the shield conductor 3, the sheet of composition B, the stripline conductor 4, the sheet of composition B, the shield conductor 3, and the sheet of composition B are laminated and printed in this order, and FIG. A laminated body as shown in the cross-sectional view of was prepared. After thermocompression bonding at 80 ° C. and cutting into individual elements, heat treatment was performed at 400 ° C. in the air to disperse organic substances. When a CuO paste was used, it was heat-treated in hydrogen, reduced to Cu metal, and fired in nitrogen. In the case of an Ag conductor, it was fired in air. Then, a commercially available Cu paste was baked at 600 ° C. in nitrogen as the external electrodes 5 and 6 to obtain a composite laminated resonator.

A chip-type multilayer capacitor is connected to the strip electrode conductor 4 formed on each dielectric layer by an external electrode 6.
After connecting them in series via a cable and matching them so that the impedance becomes 50Ω, the results of measuring the resonance frequency, the Q value, and the temperature coefficient τf of the resonators formed on the respective dielectric layers by a network analyzer are shown in Table 4. Shown in The length of the strip line was about 9.0 mm, and the length between the shields of each dielectric layer was about 1.0 mm.

[0028]

[Table 4]

As shown in (Table 4), the resonance frequency corresponds to the relative dielectric constant of each dielectric layer. For example, the resonance frequency of each layer of the sample number b-1 is the A layer (εr
= 43) and 0.8 in the B layer (εr = 43).
It became 4 GHz. These measured values are calculated values of the resonance frequency calculated from the strip line length and the relative permittivity (f = c
/ (4 × L × √εr), f: resonance frequency, L: strip line length, εr: relative permittivity, c: speed of light). The Q value was as high as 100 or more, which was excellent, regardless of whether silver or copper was used for the conductor layer. In each of the combinations, defects such as interfacial peeling, warpage, and cracks, which may occur due to differences in the thermal expansion coefficient and sintering shrinkage behavior of each dielectric layer, were not confirmed.

Therefore, the composite laminated dielectric porcelain component of the present invention can be used as a composite high-frequency resonance device that can handle a plurality of transmission / reception frequencies. It is needless to say that the composite laminated dielectric porcelain part can be applied for purposes other than the above.

[0031]

As is apparent from the above description, the present invention does not cause delamination, warpage, cracks or the like by integral firing, and has a large Q and a small τf in all the dielectric layers. It is a composite laminated dielectric porcelain part, and it is possible to manufacture a small, high-performance composite high-frequency resonance device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a composite laminated dielectric resonator according to an embodiment of the present invention.

FIG. 2 is a printed pattern diagram of an internal conductor of the resonator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dielectric layer A 2 Dielectric layer B 3 Shield conductor 4 Strip line conductor 5, 6 External electrode

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // H01P 7/08 H01P 7/08

Claims (2)

[Claims] 1. A dielectric ceramic composition comprising bismuth oxide and niobium oxide as main components, two or more dielectric layers having different relative dielectric constants, and a conductor layer mainly containing silver or copper. A composite laminated dielectric porcelain part characterized by being laminated. 2. The dielectric ceramic composition constituting all the dielectric layers has a relative dielectric constant εr of 35 or more and a Qf product of 1000 GHz.
As described above, the absolute value of the temperature coefficient of the resonance frequency | τf |
2. The composite laminated dielectric ceramic component according to claim 1, wherein the component is not more than pm / ° C.