JP3081605B1 - Dielectric porcelain composition, porcelain capacitor using the same, and method of manufacturing the same - Google Patents

Abstract

Kind Code: A1 A dielectric ceramic composition having a small size, a large capacity, stable characteristics even in a high-frequency range, and realizing firing at a low temperature, can significantly reduce the manufacturing cost. Provided are a ceramic capacitor using the same and a method for manufacturing the same. The A TiO ₂ comprises 25~85mol%, the remainder to the main composition to ZnO and unavoidable impurities, CuO
0.5 to 15 wt%, the MnO ₂ 0.1 to 10 wt%, characterized by comprising the addition of glass composition 0.5 to 10 wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric porcelain composition, a porcelain capacitor using the same, and a method for producing the same, and more particularly, to a small and large-capacity capacitor having stable characteristics even in a high-frequency range, TECHNICAL FIELD The present invention relates to a dielectric porcelain composition, a porcelain capacitor using the same, and a method for producing the same, which is capable of significantly reducing the production cost by realizing the sintering of the composition.

[0002]

BACKGROUND OF THE INVENTION ceramic capacitor, in devices utilizing dielectric properties of the ceramic, and TiO ₂ of rutile,
Of perovskite-type BaTiO _3, MgTiO _3, CaT
A capacitor having desired characteristics can be obtained by using a dielectric material such as iO ₃ or SrTiO ₃ alone or by combining them.

[0003] Ceramic capacitors are classified into single-layer capacitors and multilayer capacitors. The single-layer ceramic capacitor is formed by press-molding the above-described material into a predetermined shape, for example, a pellet (disc-like), rod (cylindrical), or chip (square-shaped) molded body. It can be obtained by firing at a temperature of 1400 ° C. to form a sintered body, and forming electrodes on both front and back surfaces of the sintered body.

[0004] In addition, the multilayer ceramic capacitor is prepared by kneading the above-mentioned material, an organic binder and an organic solvent to form a slurry, forming the slurry into a sheet shape by a doctor blade method, degreased to form a green sheet, and forming a green sheet on the green sheet. After printing an electrode made of a noble metal such as Pt or Pd, these green sheets are stacked in the thickness direction and pressed to form a laminate.
It can be obtained by firing at a temperature of 400 ° C.

[0005]

However, in the above-mentioned conventional ceramic capacitors, it is necessary to extend the application range in a high frequency region such as a microwave, and characteristics such as relative permittivity, dielectric loss, and insulation resistance are required. However, there is a demand for one having higher characteristics and higher reliability. However, current dielectric materials have not yet sufficiently met these requirements. In particular, in the case of a multilayer ceramic capacitor, 120
It is necessary to bake at a temperature of 0 to 1400 ° C. Also, it is necessary to use a noble metal such as Pt or Pd which is stable even at a high temperature for the internal electrode material, and there is a problem that it is difficult to reduce the cost.

The present invention has been made in view of the above circumstances, and has a small size, a large capacity, stable characteristics even in a high frequency range, and realizes firing at a low temperature, thereby reducing the manufacturing cost. It is an object of the present invention to provide a dielectric porcelain composition which can greatly reduce the porosity, a porcelain capacitor using the same, and a method for producing the same.

[0007]

In order to solve the above-mentioned problems, the present invention provides the following dielectric ceramic composition, a ceramic capacitor using the same, and a method of manufacturing the same. That is, the dielectric ceramic composition according to claim 1 is a TiO ₂ 2
The main composition containing 5 to 85 mol% and the balance being ZnO and unavoidable impurities contains 0.5 to 15% by weight of CuO,
0.1 to 10% by weight of O ₂ , 0 to 10% by weight of Al ₂ O ₃
%, Bi ₂ O ₃ and 0.001 to 10 wt%, is characterized by comprising the addition of glass composition 0.5 to 10 wt%.

[0008] The dielectric porcelain composition according to a second aspect is the dielectric porcelain composition according to the first aspect, wherein the glass composition
Materials include borate glass, borosilicate glass, zinc borate glass, and borate
It must be either zinc silicate glass or lead borate glass.
It is characterized by.

[0009] The porcelain capacitor according to claim 3 is characterized in that:
3. Both surfaces of an element comprising the dielectric ceramic composition according to 1 or 2
Characterized in that electrodes are formed on the substrate.

[0010] The porcelain capacitor according to claim 4 is characterized in that :
3. A sheet-like material comprising the dielectric ceramic composition according to 1 or 2.
Characterized by alternately laminating dielectric layers and electrode layers
And

A method for producing the dielectric porcelain composition according to claim 5.
The method contains 25 to 85 mol% of TiO ₂ and the remainder is Zn.
O and 0.5% CuO in the main composition as unavoidable impurities
-15% by weight, 0.1-10% by weight of MnO ₂ , Al ₂ O
₃ 0-10 wt%, the Bi ₂ O ₃ 0.001 to 10 weight
%, A powder containing 0.5 to 10% by weight of a glass composition
Into a bulk or sheet-like molded body,
Firing this molded body at a temperature of 830 to 950 ° C.
Features.

The method for producing a dielectric porcelain composition according to claim 6 is the same as the method for producing a dielectric porcelain composition according to claim 5.
Forming an electrode on one main surface of the sheet-shaped molded body,
Next, a plurality of the compacts are stacked in the thickness direction and pressed.
And sintering the laminate at the above temperature.
It is characterized by.

[0013]

[0014]

The dielectric ceramic composition according to the first aspect of the present invention contains 25 to 85 mol% of TiO ₂ , and the balance is Zn.
O and 0.5% CuO in the main composition as unavoidable impurities
-15% by weight, 0.1-10% by weight of MnO ₂ , Al ₂ O
₃ 0-10 wt%, the Bi ₂ O ₃ 0.001 to 10 weight
%, By the addition of glass composition 0.5 to 10 wt%, a high dielectric constant, low dielectric loss, it is possible to realize high insulation resistance, the high frequency region such as microwave <br/> Characteristics are stabilized. This improves the reliability in the high frequency range .

Here, the content of TiO ₂ is 25 to 85 m
The reason for setting to ol% is that if it is less than 25 mol%, the dielectric loss increases, and if it exceeds 85 mol%, the sinterability decreases and a dense sintered body cannot be obtained. Also, the reason for setting the content of ZnO to the balance other than TiO ₂ , that is, 15 to 75 mol%, is that if it is less than 15 mol%, the sinterability is reduced and a dense sintered body cannot be obtained. Is increased.

CuO is added to improve the dielectric loss, and its amount is preferably 0.5 to 15% by weight. If the amount is less than 0.5% by weight, the effect of improving the dielectric loss cannot be obtained, and if it exceeds 15% by weight, the dielectric loss increases. MnO ₂ is added to improve dielectric loss, and its addition amount is preferably 0.1 to 10% by weight. If the amount is less than 0.1% by weight, the effect of improving the dielectric loss cannot be obtained, and if it exceeds 10% by weight, the dielectric loss increases.

The glass composition is added as a sintering aid in order to improve the wettability in the grain boundary layer during low-temperature firing and to enhance the sinterability.
Is preferred. If the content is less than 0.5% by weight, a dense sintered body cannot be obtained because the effect as a sintering aid does not appear,
If the content exceeds 10% by weight, the dielectric loss increases. The glass composition has good wettability with TiO ₂ and ZnO, which are components of the main composition, even when added, and softens and / or melts at a temperature of 850 to 950 ° C. Glass is preferable, and for example, borate glass, borosilicate glass, zinc borate glass, zinc borosilicate glass, and lead borate glass are preferable.

Al ₂ O ₃ is added to improve dielectric loss, and the amount of Al ₂ O ₃ is preferably 0 to 10% by weight. If the amount exceeds 10% by weight, the dielectric loss increases. Bi ₂ O ₃ is added to improve the dielectric loss, and its amount is preferably 0.001 to 10% by weight. If the amount is less than 0.001% by weight, the effect of improving the dielectric loss cannot be obtained, and if it exceeds 10% by weight, the dielectric loss increases. Note that the above-described effect of improving the dielectric loss can be confirmed by measuring tan δ (loss coefficient).

According to a fifth aspect of the present invention, there is provided a method for producing a dielectric porcelain composition, wherein TiO ₂ is contained in an amount of 25 to 85 mol%, and the balance is Z.
CuO is added to the main composition of nO and unavoidable impurities in an amount of 0.1%.
5 to 15% by weight, MnO ₂ 0.1 to 10% by weight, Al ₂
O ₃ 0-10 weight%, the Bi ₂ O ₃ 0.001 to 10 fold
%, A glass composition added with 0.5 to 10% by weight of a powder is formed into a bulk or sheet-like molded body,
By firing this molded body at a temperature of 830 to 950 ° C., the glass composition as a sintering aid improves the wettability of the grain boundary layer in the firing process, and bonds the powder particles in the molded body together. In addition, the sintering proceeds by reducing the voids between the powder particles. This makes it possible to obtain a dense and high-strength sintered body by firing at a low temperature of 830 to 950 ° C.

According to a sixth aspect of the present invention, there is provided a method for producing a dielectric ceramic composition, wherein an electrode is formed on one main surface of a sheet-like molded body, and then a plurality of such molded bodies are laminated in the thickness direction and pressurized. By firing this laminate at the above-mentioned temperature, a metal such as Ag, which is inexpensive compared to a noble metal such as Pt or Pd, can be used as an internal electrode material, and a noble metal such as Pt or Pd can be used. There is no need to use it as an electrode material. Thereby, cost reduction can be achieved without deteriorating characteristics.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the dielectric ceramic composition of the present invention, a ceramic capacitor using the same, and a method of manufacturing the same will be described with reference to the drawings. FIG. 1 is a sectional view showing a ceramic capacitor (porcelain capacitor) according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes a bulk dielectric, 2 denotes a terminal electrode, Is a lead wire, and 4 is an epoxy resin.

The dielectric 1 is composed of 25 to 85 mol of TiO ₂ .
% Of the main composition containing ZnO and unavoidable impurities in the balance, and 0.5 to 15% by weight of CuO and 0.1 to 0.1% of MnO ₂ .
10 wt%, the Al ₂ O ₃ 0 wt%, the Bi ₂ O ₃
0.001 to 10 % by weight , the glass composition is 0.5 to 10 %
It is a dielectric ceramic composed of a material composition added by weight%.

The terminal electrode 2 is made of Ag or an Ag alloy. As an Ag alloy, for example, 90A
g-10Pd or the like is preferably used. This ceramic capacitor has a relative dielectric constant (ε) of 15 to 70 and a tan δ (loss coefficient) of 1.7 to 7.2 × 10 ⁻³ , and has stable characteristics even in a high frequency region.

Next, a method of manufacturing the ceramic capacitor will be described. First, TiO ₂ , ZnO, CuO, and Mn in powder form are used so as to have the material composition of the present embodiment.
O ₂ , Al ₂ O ₃ , glass composition, and Bi ₂ O ₃ are each weighed in a predetermined amount, and these powders are placed in a ball mill together with a predetermined amount of a dispersion medium such as water (or ethanol or acetone) and mixed for a predetermined time. -Pulverization, followed by dehydration (or de-ethanol, de-acetone) and drying. Next, the dried powder is heated at a temperature of 550 to 750 ° C. for 0.5 to 5.0.
The mixture was calcined for a period of time, and ground for 1 to 24 hours using a raikai machine (or an automatic mortar) to obtain a calcined powder having a predetermined particle size.

Next, after adding a predetermined amount of an organic binder to the calcined powder, the mixture was uniformly mixed and granulated using a raikai machine or the like to obtain a granulated powder (agglomerated) having a predetermined particle size. As the organic binder, an aqueous solution of ethyl cellulose or the like was used in addition to an aqueous solution of polyvinyl alcohol (PVA). Next, using a molding machine, the granulated powder is formed into pellets having a diameter of 20 mm and a thickness of 2 mm.
At a temperature of 0.5 to 10.0 hours to obtain a disk-shaped dielectric 1 of the present embodiment.

Table 1 shows the electrical characteristics at each composition ratio.

[Table 1]

Here, the sample No. 1 to No. 9
And the composition ratio of TiO ₂ and ZnO is variously changed within the range of the composition ratio of the present invention.
Regarding the composition ratio of CuO and Al ₂ O ₃ ,
The composition ratio of nO ₂ , Bi ₂ O ₃ and the glass composition was set to one point. The relative permittivity and tan δ were measured at 25 ° C. under the conditions of 1 MHz and 1 V _rms .

As is apparent from Table 1, these samples (No. 1 to No. 9) have a high relative dielectric constant,
It can be seen that tan δ is also improved. In addition, it is understood that the insulation resistance is high and the insulating properties are good. Furthermore, these samples (No. 1 to N
o. When the surface state of 9) was observed, no voids or the like were observed at the grain boundaries, and it was confirmed that the sintered body was dense.

As described above, according to the ceramic capacitor of this embodiment, the dielectric 1 is made of TiO ₂ and
８５85 mol%, the balance being ZnO and unavoidable impurities, the main composition containing 0.5 to 15% by weight of CuO and MnO
₂ 0.1 to 10 wt%, the Al ₂ O ₃ 0 wt%,
Since the material composition contains 0.001 to 10% by weight of Bi ₂ O ₃ and 0.5 to 10% by weight of the glass composition, a high relative dielectric constant, a low dielectric loss, and a high insulation resistance can be realized. In addition, characteristics in a high frequency region such as microwaves can be stabilized. Therefore, the reliability in the high frequency region can be improved.

According to the method for manufacturing a ceramic capacitor of the present embodiment, 0.5 to 15% by weight of CuO and MnO ₂ are contained in a powder containing 25 to 85 mol% of TiO ₂ and the balance being ZnO and unavoidable impurities. 0.1 to 10% by weight,
The Al ₂ O ₃ 0~10 wt%, the Bi ₂ O ₃ 0.001 to 1
0% by weight, and 0.5 to 10% by weight of a glass composition were added to form a mixed powder, and the mixed powder was molded into a bulk molded body, which was fired at a temperature of 830 to 950 ° C. A dense and high-strength sintered body can be produced by low-temperature firing.

[Second Embodiment] FIG. 2 is a cross-sectional view showing a multilayer ceramic capacitor according to a second embodiment of the present invention. In the drawing, reference numeral 11 denotes a sheet-like dielectric layer;
Is a thin internal electrode, 13 and 14 are terminal electrodes, which are formed by alternately stacking eight dielectric layers 11 and seven internal electrodes 12.

The dielectric layer 11 is made of TiO ₂ of 25 to 85 m.
% of CuO and 0.5 to 15% by weight of CuO and 0.1% of MnO ₂ in the main composition containing ZnO and unavoidable impurities in the balance.
1 to 10% by weight, 0 to 10% by weight of Al ₂ O ₃ , Bi ₂ O ₃
From 0.001 to 10% by weight, and the glass composition from 0.5 to 1%.
It is a sheet-like ceramic having a material composition added with 0% by weight.

The internal electrode 12 and the terminal electrodes 13 and 14 are
It is made of Ag or an Ag alloy. As the Ag alloy, for example, 90Ag-10Pd is preferably used. The relative dielectric constant (ε) of this multilayer ceramic capacitor is 15 to 70, and tan δ (loss coefficient) is 1.7 to
It is 7.2 × 10 ⁻³ , and has stable characteristics even in a high frequency range.

Next, a method of manufacturing the multilayer ceramic capacitor will be described. First, powdered TiO ₂ , ZnO, CuO, M
A predetermined amount of each of nO ₂ , Al ₂ O ₃ , glass composition, and Bi ₂ O ₃ is weighed, and these powders are placed in a ball mill together with a predetermined amount of a dispersion medium such as water (or ethanol or acetone) for a predetermined time. After mixing and pulverization, dehydration (or de-ethanol and de-acetone) and drying were performed.

Next, a predetermined amount of an organic binder and an organic solvent were added to the dried powder, and the resulting mixture was kneaded using a raikai machine, a kneader or the like to obtain a slurry having a predetermined viscosity. As an organic binder, PVA (polyvinyl alcohol)
In addition to the aqueous solution, an ethyl cellulose aqueous solution or the like was used.

Next, the slurry is formed into a sheet by a doctor blade method and degreased to form a green sheet. After the internal electrode 12 made of Ag or an Ag alloy is printed on the green sheet in a predetermined pattern, the green sheet is formed. The green sheets were stacked in the thickness direction, and then pressed in the thickness direction to form a laminate. Next, this laminated body was fired at a temperature of 830 to 950 ° C. to form terminal electrodes 13 and 14 on both side surfaces. As described above, a multilayer ceramic capacitor in which the dielectric layers 11 and the internal electrodes 12 were alternately stacked was able to be manufactured.

As described above, according to the multilayer ceramic capacitor of this embodiment, the dielectric layer 11 is made of TiO.
₂ to 25 to 85 mol%, with the balance being ZnO and unavoidable impurities, the main composition containing 0.5 to 15% by weight of CuO, 0.1 to 10% by weight of MnO ₂ , and 0 to 1 of Al ₂ O ₃ .
0% by weight , 0.001 to 10% by weight of Bi ₂ O ₃ , and 0.5 to 10% by weight of a glass composition are added. ,
High insulation resistance can be realized, and high
Characteristics in the frequency domain can be stabilized. Therefore, reliability in a high frequency region can be improved.

According to the method for manufacturing a multilayer ceramic capacitor of the present embodiment, the main composition containing 25 to 85 mol% of TiO ₂ and the balance of ZnO and unavoidable impurities includes:
CuO 0.5 to 15 wt%, the MnO ₂ 0.1 to 10
Wt%, the Al ₂ O ₃ 0 wt%, the Bi ₂ O ₃ 0.0
01 to 10% by weight, the glass composition is 0.5 to 10% by weight
A green sheet formed by molding the added powder is laminated in the thickness direction to form a laminate.
Since it is fired at a temperature of 0 ° C., the material of the internal electrode 12 is Pt
A relatively inexpensive metal such as Ag can be used as compared with a noble metal such as Pd or Pd, and there is no need to use a noble metal such as Pt or Pd as an electrode material. Therefore, cost reduction can be achieved without deteriorating characteristics.

As described above, the embodiments of the dielectric ceramic composition of the present invention, the ceramic capacitor using the same, and the method of manufacturing the same have been described with reference to the drawings. However, the specific structure is limited to the above embodiments. However, the design can be changed without departing from the scope of the present invention. For example, in the multilayer ceramic capacitor according to the second embodiment, eight dielectric layers 11 and seven internal electrodes 12 are alternately stacked.
The size and the number of layers can be appropriately changed depending on the required capacity and characteristics.

[0041]

As it has been described above, according to the dielectric ceramic composition according to the first aspect of the present invention, the TiO ₂ 25 to 85
wherein mol%, the main composition of the balance between ZnO and unavoidable impurities, 0.5 to 15 wt% of CuO, the MnO ₂ 0.1 to 10 wt%, the Al ₂ O ₃ 0 wt%, Bi
0.001 to 10% by weight of ₂ O ₃ and 0.5 % of the glass composition
Addition of 10 to 10% by weight makes it possible to realize a high relative dielectric constant, a low dielectric loss, a high insulation resistance, and to stabilize characteristics in a high frequency region such as a microwave. Therefore, reliability in a high frequency region can be improved.

[0042] According to the manufacturing method of claim 5 dielectric ceramic composition as set forth, the TiO ₂ comprises 25～85Mol%, the main composition of the balance between ZnO and unavoidable impurities, 0.5 to 15 weight CuO %, MnO ₂ is 0.1 to 10% by weight,
The Al ₂ O ₃ 0~10 wt%, the Bi ₂ O ₃ 0.001 to 1
A powder to which 0% by weight and a glass composition of 0.5 to 10% by weight are added is molded into a bulk or sheet-like compact, and the compact is fired at a temperature of 830 to 950 ° C. By firing, a dense and high-strength sintered body can be produced.

According to the method for producing a dielectric ceramic composition of the sixth aspect , an electrode is formed on one principal surface of a sheet-shaped molded body, and then a plurality of molded bodies are stacked in the thickness direction and pressed. Since the laminate is fired at the above temperature, a less expensive metal such as Ag can be used for the internal electrode material as compared with a noble metal such as Pt or Pd.
It is not necessary to use a noble metal such as d as an electrode material.
Therefore, cost reduction can be achieved without deteriorating product characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a single-layer ceramic capacitor according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a multilayer ceramic capacitor according to a second embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 bulk dielectric 2 terminal electrode 3 lead wire 4 epoxy resin 11 dielectric layer 12 internal electrode 13, 14 terminal electrode

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 9-20555 (JP, A) JP 10-212163 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C04B 35/46 CA (STN) REGISTRY (STN) WPI (DIALOG)

Claims (6)

(57) [Claims] 1. A main composition containing 25 to 85 mol% of TiO ₂ and the balance being ZnO and unavoidable impurities,
0.5 to 15 wt%, the MnO ₂ 0.1 to 10 wt%, the Al ₂ O ₃ 0 wt%, the Bi ₂ O ₃ 0.001
A dielectric porcelain composition characterized in that a glass composition is added in an amount of 0.5 to 10% by weight and a glass composition in an amount of 0.5 to 10% by weight. 2. The glass composition according to claim 1, wherein the glass composition is borate glass, borosilicate
Acid glass, zinc borate glass, zinc borosilicate glass, lead borate
2. The method according to claim 1, wherein the material is one of glass.
A dielectric porcelain composition as described in the above. 3. The dielectric ceramic composition according to claim 1, wherein
It is characterized by forming electrodes on both sides of a device made of
And porcelain capacitors. 4. The dielectric ceramic composition according to claim 1, wherein
The dielectric layer and the electrode layer are alternately stacked.
A porcelain capacitor characterized by being layered. 5. A composition containing 25 to 85 mol% of TiO ₂ ,
Part is ZnO and unavoidable impurities, the main composition is CuO
0.5 to 15% by weight, MnO ₂ 0.1 to 10 % by weight
%, The Al ₂ O ₃ 0 wt%, the Bi ₂ O ₃ 0.001
10 to 10% by weight, glass composition 0.5 to 10% by weight
Molded powder into a bulk or sheet
The molded body is fired at a temperature of 830 to 950 ° C.
A method for producing a dielectric porcelain composition. 6. An electrode is provided on one main surface of said sheet-like molded body.
Then, a plurality of the compacts are laminated in the thickness direction.
And pressurized to form a laminate, and the laminate is fired at the above temperature.
The dielectric ceramic composition according to claim 5, wherein
Manufacturing method.