JP2002338344A - Reduction resistant dielectric composition and ceramic electronic parts using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reduction resistant dielectric composition in which change rate of electrostatic capacity with temperature satisfies JIS standard B characteristic or EIA standard X7R characteristic, dielectric constant is high and commodity development to high capacity region can be made, sintering assistant composition is uniformly dispersed in a main component without segregation and excellent electric characteristics for middle and high voltage can be revealed and to provide a ceramic electronic parts using the same. SOLUTION: The reduction resistant dielectric composition has BET specific surface area of within a range of 2.0 to 3.0 m<2> /g, consists essentially of BaTiO3 in which mole ratio of Ba/Ti is within a range of 0.993 to 1.007, contains metal oxide or a compound becoming the metal oxide by firing as an additive and further contains SiO2 based compound as a sintering assistant with respect to the BaTiO3 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a medium-to-high voltage switching power supply circuit, DC-DC converter circuit, lighting inverter circuit, etc., in which the internal electrodes are made of a base metal and satisfy JIS B characteristics or EIA X7R characteristics. TECHNICAL FIELD The present invention relates to a reduction-resistant dielectric composition used for electronic components typified by multilayer ceramic capacitors widely used as ceramic components and ceramic electronic components using the same.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become lighter and thinner, as represented by notebook type personal computers and the like, ceramic capacitors, which are one of the important passive components used in electronic devices, have been changed from the conventional disk type to the multilayer type. Is rapidly progressing, which contributes to downsizing of switching power supply circuits and DC-DC converter circuits and resin molding. According to the data of credit bureaus, it is certain that the lamination rate of ceramic capacitors will exceed 90% in the year 2005, not only for low-rated voltage products but also for medium- and high-voltage products and also for safety standard products. It is only a matter of time before the lamination spreads.

For example, for a primary side snubber of a switching power supply circuit, the rated voltage is 630 VDC and JIS standard B
Many multi-layer ceramic capacitors for medium and high pressures satisfying the characteristics or the EIA standard X7R characteristics are used, and are forming a large market. In a normal multilayer ceramic capacitor, an effective layer for obtaining capacitance is formed by alternately laminating a plurality of ceramic dielectric layers and internal electrode layers, and overall dimension adjustment and internal hermetic sealing are formed above and below the effective layer. For this purpose, an ineffective layer consisting of only a ceramic dielectric layer is formed. Then, the electrical connection of the internal electrode layers is performed by providing external electrodes on both end surfaces where their terminal portions are exposed,
On the surfaces of these external electrodes, Sn plating or Sn-P is applied on Ni plating so that solder mounting can be performed easily and without any trouble.
It has a structure in which b-type solder plating is applied in a layered manner.

Conventionally, a dielectric composition used for such a multilayer ceramic capacitor has been made of BaT which is a main component.
The mainstream is one in which several types of additives are added to iO _3. For example, Japanese Patent Publication No. 3-23504 discloses BaTiO ₃ with N.
A composition in which b ₂ O ₅ and CoO are added is disclosed. According to this composition, Nb ₂ O ₅ and CoO act as components for flattening the rate of change in capacitance with temperature, and satisfy EIA standard X7R characteristics. It is described. Also 3-610
No. 87 discloses BaTiO ₃ containing Nb ₂ O ₅ , CoO, Ce.
O ₂ and compositions plus ZnO is disclosed, Nb ₂
O ₅ and CoO flatten the rate of change of capacitance with temperature,
It is described that O ₂ lowers the firing temperature and ZnO improves the electrical properties.

[0005] However, the above-mentioned dielectric composition has an internal electrode.
It is based on the premise that a Pd-based precious metal is used as the pole,
In particular, the cost of raw materials is
There was a problem in terms. To solve this, Pd-based
Low cost Ni or Ni instead of precious metals
It is known to use alloys that
Ratio of base metal internal electrode products in backpack capacitors is rapidly increasing
are doing. Since Ni is a base metal, the product of conventional noble metals
Fired in an oxygen atmosphere like a multilayer ceramic capacitor
Is impossible, Ni is oxidized in low oxygen partial pressure atmosphere
It must be fired so as not to be. Ceramic co
BaTiO known for capacitors _ThreeRepresented by
Perovskite oxide has a high temperature of 1000 ° C or higher.
Exposed to atmosphere below the oxidation-reduction equilibrium oxygen partial pressure of Ni
To reduce the insulation resistance or apply an electric field.
Reliability test in the condition, so-called failure rate in load life increases
It functions as a ceramic dielectric for capacitors.
It will not work.

[0006] In order to solve this problem, these perovskite oxides can change the stoichiometric ratio of ions existing at the A site and the B site, or can form a solid solution as a donor in the crystal lattice. Many reduction-resistant dielectric compositions composed of perovskite oxide and a small amount of additives by utilizing the property of being hardly reduced even by performing the above-described heat treatment by adding ions or the like. Have been devised and disclosed. In the past, reduction-resistant dielectric compositions mainly used JIS F characteristics with a large temperature change rate of capacitance, but in recent years active material development has led to JIS B characteristics with a small temperature change rate. Or EIA
Standard X7R characteristics are applied to thin-layer, large-capacity multilayer ceramic capacitors. For example, JP-A-8-124784 discloses that BaTiO ₃ is used as a main component and Mg is used as a sub-component.
A reduction-resistant dielectric composition that can use a base metal such as Ni and a Ni-based alloy containing SiO ₂ and at least one selected from O, Y ₂ O ₃ , BaO, and CaO is disclosed. Japanese Patent Application Laid-Open No. 9-171938 discloses BaTi
MgO as an auxiliary component and Li ₂ O—B ₂ O ₃ — (Si, Ti) O ₂ as a sintering aid component with respect to the main component of the O ₃ system.
A reduction-resistant dielectric composition containing a system oxide is disclosed. Thereby, the temperature change rate of the capacitance is small,
Moreover, large-capacity monolithic ceramic capacitors using inexpensive Ni-based internal electrodes have been commercialized mainly for low rated voltage products of 16 to 50 VDC.

[0007]

However, many of the conventional reduction-resistant dielectric compositions have been developed for multilayer ceramic capacitors having a low rated voltage and a large capacity.
It is not suitable for medium and high voltage applications with a rated voltage of 630 VDC or higher in terms of electrical characteristics. In addition, it is difficult to say that the conventional reduction-resistant dielectric composition was designed in consideration of the uniform dispersibility and reactivity of a small amount of additives to the perovskite oxide as a main component, and it was difficult to control the process. The characteristics and quality of products fluctuate due to unpredictable factors, leading to a decrease in yield and poor reliability. For example, a reduction-resistant dielectric composition manufactured by a calcining mixing method, which is a conventional process, is particularly Li ₂ O—B ₂ O ₃ — (Si, T
i) It was difficult to uniformly disperse a sintering aid component such as an O ₂ -based or BaO-SiO ₂ -based composition, and the sintering aid component was a non-uniformly dispersed composition. As a result, a local abnormal reaction occurs in the reaction process during sintering, the crystal grain size varies greatly, and a heterogeneous microstructure with many pores is formed,
There has been a problem that variations in capacitance and dielectric loss occur, the dielectric breakdown voltage is low, the distribution of failure times in the ultra-accelerated life test (HALT) is wide, and the average failure time is short. Also, even if the sintering aid components are uniformly dispersed,
Since the crystal grain size and the microstructure of the multilayer ceramic capacitor manufactured differ greatly depending on the BET specific surface area value of the BaTiO ₃ powder as the main component and the magnitude of the Ba / Ti molar ratio, the dielectric constant and the capacitance among the electric characteristics are particularly large. Had a large change in the temperature change rate.

Therefore, the present invention solves the above problems,
By limiting the BET specific surface area value and the Ba / Ti molar ratio of the main component BaTiO ₃ powder, the temperature change rate of the capacitance satisfies the JIS standard B characteristic or the EIA standard X7R characteristic and the dielectric constant is high. A high-capacity product that can be deployed in a high capacity region, and the sintering aid component is uniformly dispersed in the main component without segregation, and exhibits excellent electrical characteristics for medium and high pressure applications. An object of the present invention is to provide a composition, and to provide a ceramic electronic component represented by a base metal internal electrode multilayer ceramic capacitor having a high capacity and excellent in durability and reliability using the reduction-resistant dielectric composition.

[0009]

In order to solve this problem, a reduction-resistant dielectric composition according to the present invention has a BET specific surface area value in the range of 2.0 to 3.0 m ² / g, And Ba
With respect to BaTiO ₃ which is a main component having a molar ratio of / Ti within the range of 0.993 to 1.007, at least an oxide of Dy or a compound which becomes an oxide of Dy by firing, an oxidation of Mg Or a compound that becomes an oxide of Mg by firing, an oxide of Mn or a compound that becomes an oxide of Mn by firing, and is represented by a general formula of Ba _{1- X} Ca _X SiO ₃ as at least a sintering aid. , X is 0 ≦ X
≦ 1. As a result, it has excellent reduction resistance, has a very controlled crystal grain size, has a dense and uniform microstructure, has a high dielectric constant, and has electrical characteristics and durability comparable to those for medium and high pressures A reduction-resistant dielectric composition for producing a reliable multilayer ceramic capacitor is obtained.

The BET has a specific surface area of 2.0-3.
B, which is a main component having a molar ratio of Ba / Ti within a range of 0.993 to 1.007, within a range of 0 m ² / g.
By defining the amount of the additive and the sintering aid with respect to 100 mol of aTiO _{3, a} reduction-resistant dielectric composition having better electric characteristics and durability reliability can be obtained.

Further, the reduction-resistant dielectric composition of the present invention comprises:
It is represented by a general formula of Ba _1-X Ca _X SiO ₃ , wherein X is 0 ≦ X ≦
The sintering aid component in the range of 1 is adjusted by adding ammonia water dropwise while stirring a mixed solution of an aqueous solution of Ca and Ba acetate and an ethanol solution of metal alkoxide of Si. As a result, the sintering aid component containing Ca, Ba, and Si is changed in terms of BET specific surface area and Ba / T
Because the i is uniformly coated around BaTiO ₃ particles, which is a main component having a limited molar ratio of i, there is no local abnormal reaction during firing, and the sintering aid components are uniformly dispersed. A reduction-resistant dielectric composition capable of forming a crystal grain size and a dense structure can be obtained.

A ceramic electronic component according to the present invention is a chip-type, mold-type or lead-type multilayer ceramic in which a ceramic dielectric layer forming an effective layer and an ineffective layer is formed of the above-mentioned reduction-resistant dielectric composition. This capacitor is mainly used for medium and high pressures in a high-capacity region, and can be properly used according to the needs of the user by making use of its characteristics.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first aspect of the present invention, the specific surface area of BET is in the range of 2.0 to 3.0 m ² / g, and the molar ratio of Ba / Ti is 0. .993 ~
It contains, as an additive, a metal oxide or a compound which becomes a metal oxide by firing with respect to BaTiO ₃ which is a main component within the range of 1.007, and Si as a sintering aid.
A reduction-resistant dielectric composition characterized by containing an O ₂ -based compound, which is capable of forming a base metal internal electrode multilayer ceramic capacitor having excellent electrical characteristics and durability reliability. It has the effect of realizing a dielectric composition.

According to a second aspect of the present invention, a BET
Is in the range of 2.0 to 3.0 m ² / g, and the molar ratio of Ba / Ti is 0.993 to 1.007.
To BaTiO ₃ , which is a main component in the range of, by adding an oxide of Dy as an additive or firing
a compound that becomes an oxide of y, an oxide of Mg or a compound that becomes an oxide of Mg when fired, an oxide of Mn or a compound that becomes an oxide of Mn when fired, and contains at least Ba ₁₋ as a sintering aid. A reduction-resistant dielectric composition represented by the general formula of _X Ca _X SiO ₃ , wherein X contains a component in the range of 0 ≦ X ≦ 1, and has excellent reduction resistance. However, it has the effect of realizing a reduction-resistant dielectric composition capable of forming a base metal internal electrode multilayer ceramic capacitor having electrical characteristics comparable to those for medium and high pressures.

According to a third aspect of the present invention, a BET
Is in the range of 2.0 to 3.0 m ² / g, and the molar ratio of Ba / Ti is 0.993 to 1.007.
Is an oxide of Dy or a compound which becomes an oxide by firing with respect to 100 moles of BaTiO _{3 as} a main component in the range of 0.2 to 1 in terms of oxide Dy ₂ O ₃ .
3 mol, an oxide of Mg or a compound that becomes an oxide by firing 0.1 to 1.2 moles in terms of oxide MgO;
It contains 0.02 to 0.12 mol in terms of n ₃ O ₄ , and is represented by a general formula of Ba ₁ -x Ca _x SiO ₃ as a sintering aid, wherein X is 0
A reduction-resistant dielectric composition containing 0.5 to 3.5 mol of a component consisting of ≦ X ≦ 1;
Excellent reduction resistance is obtained in an atmosphere at or below the oxidation-reduction equilibrium oxygen partial pressure of Ni at the firing temperature, and it is possible to form a Ni internal electrode multilayer ceramic capacitor having a high dielectric constant and a high durability reliability. This has the effect of realizing a reduction-resistant dielectric composition.

[0016] The invention described in claim 4 of the present invention is defined by the claims.
In the invention described in 2, 3, Ba, _1-XCa_XSiO_Threeof
A component represented by the general formula, wherein X is in the range of 0 ≦ X ≦ 1
Is an aqueous solution of acetate of Ca and Ba and a metal alkoxide of Si.
While stirring the mixed solution with the sidoethanol solution,
The solution is adjusted by adding ammonia water dropwise to the solution.
a, Ba and Si-containing sintering aid components are uniformly dispersed
At the same time, the BET specific surface area value and the Ba / Ti
BaTiO, the main component with a limited metal ratio_ThreeAround particles
Local abnormalities during firing due to uniform coating
Extremely controlled with no sintering aid components dispersed without reaction
Capable of forming a dense structure with a refined crystal particle diameter
Has the effect of realizing a reduction-resistant dielectric composition
You.

According to a fifth aspect of the present invention, there is provided an effective layer having an internal electrode layer made of Ni or an alloy containing Ni as a main component between the first plurality of ceramic dielectric layers and the second layer. A base having an ineffective layer composed of a plurality of ceramic dielectric layers, and provided from both ends of the base to side portions;
A chip-type ceramic electronic component comprising a pair of external electrodes electrically connected to an internal electrode layer, wherein the ceramic dielectric layer is a reduction-resistant dielectric composition according to any one of claims 1 to 4. It has a very controlled crystal grain size and a fine microstructure, has a high capacitance, and has excellent durability reliability. This has the function of realizing a ceramic electronic component represented by a multilayer ceramic capacitor.

According to a sixth aspect of the present invention, there is provided an effective layer in which an internal electrode layer made of Ni or an alloy containing Ni as a main component is provided between a first plurality of ceramic dielectric layers and a second layer. A base having an ineffective layer composed of a plurality of ceramic dielectric layers, and provided from both ends of the base to side portions;
A mold-type ceramic electronic component comprising a pair of external electrodes electrically connected to an internal electrode layer and terminals respectively connected to the external electrodes, wherein a base and the external electrodes are embedded with a resin, Claim 1 to body layer
4, which comprises the reduction-resistant dielectric composition according to any one of the above, has a very controlled crystal grain size and a fine microstructure, has a high capacitance and is excellent in durability reliability,
This has the effect of realizing a ceramic electronic component typified by a surface-mount type medium- and high-voltage multilayer ceramic capacitor having no creeping discharge due to an abnormal voltage and having excellent durability against mechanical stress such as bending, etc.

According to a seventh aspect of the present invention, there is provided an effective layer having an internal electrode layer made of Ni or an alloy containing Ni as a main component between a first plurality of ceramic dielectric layers and a second dielectric layer. A base having an ineffective layer consisting of a plurality of ceramic dielectric layers, and provided from both ends of the base to side portions;
A lead-type ceramic electronic component comprising a pair of external electrodes electrically connected to an internal electrode layer, and lead wires respectively connected to the external electrodes, wherein a base and the external electrodes are covered with a resin, Claim 1 to dielectric layer
4, which comprises the reduction-resistant dielectric composition according to any one of the above, has a very controlled crystal grain size and a fine microstructure, has a high capacitance and is excellent in durability reliability,
Since there is no creeping discharge due to abnormal voltage and the lead wires are soldered to the circuit board, it is possible to realize ceramic electronic components typified by medium- and high-voltage multilayer ceramic capacitors to which no mechanical stress such as bending is applied. Has an action.

The invention according to claim 8 of the present invention is the invention according to claims 5 to 7, wherein the external electrode has a two-layer structure of an upper layer and a lower layer, and the lower layer is provided only on the end face of the base. In addition, since the external electrode has a two-layer structure, the electrical connection with the base metal internal electrode layer is perfect, so that a ceramic electronic component having high reliability can be realized.

BaTiO used in the practice of the invention_Three
The specific surface area value of BET and the molar ratio of Ba / Ti
Of Multilayer Ceramic Capacitor and Firing in Reducing Atmosphere
In terms of reduction resistance. BET ratio table
Area value is 3.0m^Two/ G over BaTiO_ThreeConsisting of
Multilayer ceramic capacitor using reducing dielectric composition
Lowers the capacitance value, making it difficult to deploy products in the high-capacity region
And 2.0m ^Two/ G less than BaTiO_ThreeConsisting of
Multilayer ceramic capacitor using reducing dielectric composition
Has a low breakdown voltage and guarantees the designed rated voltage.
Are difficult to perform.

The principle of measuring the specific surface area by the BET method is as follows. N ₂ molecules of a known size are attached to BaTiO ₃ powder of a fixed mass, and the surface area of the powder is known from the number of N ₂ molecules attached. Although those actual measurement method of BET shown below in data obtained by measuring the volume of the N ₂ gas is adsorbed on the powder by changing the pressure of the N ₂ gas at -195 ° C. to the boiling point of N ₂ gas Apply the formula (isothermal adsorption).

[0023]

(Equation 1)

The Ba / Ti molar ratio of BaTiO ₃ is 1.
If it exceeds 007, the capacitance becomes small, and 0.99
If it is less than 3, the temperature change rate of the capacitance becomes large, and neither is preferable. Further, as for the reactivity of BaTiO ₃ , it is preferable to use a powder having a high crystallinity because the smaller the reactivity of BaTiO _3, the easier it is to develop the B characteristics or X7R characteristics. As impurities mixed in the step of manufacturing such BaTiO ₃ powder, there are alkaline earth metals other than barium, iron, silicon, aluminum and the like. Even if these impurities are contained on the order of several thousand ppm, No problem.

Represented by the general formula of Ba ₁ -x Ca _x SiO ₃ ,
As the starting materials of the sintering aid component in which X is in the range of 0 ≦ X ≦ 1, Ca and Ba acetates and Si alkoxides can be used in general commercial products, and impurities contained in these are similar chemicals. Ba, which is a metal having
As with TiO ₃ , there is no particular problem even if it is contained in the order of several thousand ppm. In addition, general commercial products can also be used as ethanol for dissolving the alkoxide.

These acetates and alkoxides exist as hydrated ions in a water-ethanol solution, and the subsequent dropwise addition of aqueous ammonia produces fine hydroxides in the form of a colloidal suspension. ₍₃ ) When mixed with the powder, it is desirable to disperse it in a uniform state, so the concentration of ammonia water should be 1 mol / l or less, and if there is room in the equipment and time of the process, the concentration should be lower. desirable. When the concentration of the ammonia water exceeds 1 mol / liter and becomes concentrated, the above-mentioned hydroxide is generated unevenly and mixed with the BaTiO ₃ powder in a compositionally non-uniform state. This results in a reduction-resistant dielectric composition, which has completely different results from what is intended by the present invention.

The amount of each additive added to the BaTiO ₃ powder depends on the dielectric constant and dielectric loss of the multilayer ceramic capacitor to be manufactured, the temperature change rate of the capacitance, the insulation resistance, the breakdown voltage, and the high temperature load life. And from the viewpoint of reduction resistance at the firing temperature. If Dy ₂ O ₃ exceeds 1.3 moles per 100 moles of BaTiO _3, densification due to sintering will be incomplete and the dielectric constant will decrease. If it is less than 0.2 moles, the temperature change rate of the capacitance will decrease. And the high temperature load life is shortened. If MgO exceeds 1.2 moles with respect to 100 moles of BaTiO _3, a decrease in dielectric constant and an increase in dielectric loss are caused, and if less than 0.1 moles, reduction resistance at a sintering temperature is impaired, and electrical characteristics and Degrades over the life of the product. Mn ₃ O _{4 with} respect to 100 moles of BaTiO ₃
Exceeds 0.12 mol, the dielectric loss increases, and if it is less than 0.02 mol, the insulation resistance and the breakdown voltage decrease, and the high-temperature load life is shortened.

Furthermore, B is added to 100 moles of BaTiO _3.
a is represented by a general formula of _1-X Ca _X SiO ₃ , wherein X is 0 ≦ X ≦ 1
If the sintering aid component in the range of more than 3.5 mol is used, the dielectric constant is lowered and the high-temperature load life is deteriorated, and if it is less than 0.5 mol, the effect as a sintering aid cannot be obtained. In addition, densification due to sintering is incomplete, and the electrical characteristics and the life are degraded throughout.

[0029]

Next, a specific example of the present invention will be described with reference to a multilayer ceramic capacitor which is one of ceramic electronic components.

(Example 1) The outline of the experiment was as follows. According to the composition table shown in (Table 1), BaTiO ₃ powder (BT-04, manufactured by Sakai Chemical) and additives Dy ₂ O ₃ , Mg
A mixture of O and Mn ₃ O ₄ and a colloidal suspension of a sintering aid component consisting of Ca, Ba and Si are mixed in a ball mill to produce respective starting material powders. In this example, BaTiO ₃ has a BET specific surface area of 2.5 m ^2.
/ G, a powder having a Ba / Ti molar ratio of 1.000 and a sintering aid component of Ba _0.5 Ca _0.5 SiO ₃ .

[0031]

[Table 1]

The manufacturers and grades of the raw materials used are summarized in (Table 2).

[0033]

[Table 2]

Next, using the produced powder,
This is a prototype of a 216 size multilayer ceramic capacitor, which is comprehensively evaluated.

Hereinafter, a detailed trial manufacturing procedure and an evaluation method of the multilayer ceramic capacitor will be described.

BaTiO ₃ powder as the main component (specific surface area value of BET is 2.5 m ² / g, molar ratio of Ba / Ti is 1.000) and additives such as Dy ₂ O ₃ , MgO and M
A predetermined amount of each powder of n ₃ O ₄ was weighed by an electronic balance based on the composition table in (Table 1), and 35 mmφ ZrO ₂ material balls were weighed.
It is put into a polyethylene pot mill having an internal volume of 600 CC containing 0 g.

Next, based on the composition table of (Table 1), Ba,
After weighing a predetermined amount of Ca acetate and TEOS (tetraethoxysilane) with an electronic balance, the acetate is separately dissolved in 100 CC of pure water and the TEOS is dissolved in 150 CC of ethanol.

Then, a predetermined amount of 1 N aqueous ammonia was dropped into the ethanol solution while stirring the aqueous acetate solution, and stirring was continued to obtain a colloidal suspension comprising a sintering aid component.

Next, the colloidal suspension was charged into the ball mill and mixed at a rotation speed of 100 rpm for 20 hours. The mixture was filtered through a 150-mesh silk screen, poured into a stainless steel vat lined with a Teflon (registered trademark) sheet, evaporated in a draft while heating to evaporate the ethanol content, covered with aluminum and covered at 150 ° C. At a temperature of. The dried mass was pulverized in an alumina mortar, passed through a 32-mesh nylon sieve, placed in an alumina crucible, and heat-treated at 400 ° C. for 2 hours to obtain a slurry powder.

Next, a predetermined amount of the slurry powder was wetted by mixing with a solvent and a plasticizer. After wetting, a vehicle made of polyvinyl butyral resin was mixed to prepare a sheet forming slurry.

Next, the slurry was filtered through a 150-mesh silk screen and then formed into a film to obtain a ceramic raw sheet. Then, using the ceramic raw sheet and the internal electrode sheet made of the Ni paste, the sheet was laminated by a transfer method based on a predetermined lamination specification, and then cut to obtain a green chip.

Next, after chamfering the obtained green chip, a Ni paste is applied to both end surfaces and dried,
Defatted. Then, firing in a reducing atmosphere was performed using a rotary atmosphere furnace. The firing was maintained at a temperature of 1250 ° C. for 2 hours in an oxygen partial pressure atmosphere lower by about two orders of magnitude than the equilibrium oxygen partial pressure of Ni adjusted by the green gas, CO ₂ and N ₂ .
Then, an Ag paste to be an upper external electrode is applied to both end surfaces of the fired chip and baked in the air, and then Ni plating and Sn plating are applied thereon to complete the chip-type multilayer ceramic capacitor of this embodiment. Was.

FIG. 1 is a sectional view showing one embodiment of the ceramic electronic component of the present invention. The manufactured chip-type multilayer ceramic capacitor of this example was formed by alternately laminating the BaTiO ₃ -based ceramic dielectric layers 13 and the internal electrode layers 12a, 12b, and 12c containing Ni as shown in FIG. A laminated body 11 is formed by laminating a BaTiO ₃ ceramic dielectric layer 13 as an ineffective layer above and below an effective layer serving as a capacitance acquisition layer, and internal electrode layers 12 b and 12 c are provided at both ends of the laminated body 11. A lower Ni-layer external electrode 14 electrically connected to the upper electrode was provided, and an upper Ag-layer external electrode 15 was provided thereon.

Next, the electrical characteristics of the prototype chip-type multilayer ceramic capacitor were evaluated. Capacitance (Cap) and dielectric loss (tan δ) were measured by YHP LCR meter 428
The measurement was performed under a signal voltage of 1 V / 1 KHz using 4A. The dielectric constant was calculated from the measured capacitance (Cap) value, the thickness of the effective layer and the area of the counter electrode obtained by polishing the prototype chip-type multilayer ceramic capacitor. The insulation resistance value (IR) is Advantest's insulation resistance meter R8340A.
Was applied and 500 VDC was applied for 1 minute for measurement. The dielectric breakdown voltage (BDV) was obtained by measuring the DC breakdown voltage in silicone oil using a Kikusui Electronics pressure gauge. The temperature change rate of the capacitance (Cap-TC) was measured in the range of −55 to + 125 ° C. by connecting a YHP LCR meter 4284A to the thermostat. Capacitance and dielectric loss were each measured for 20 pieces, insulation resistance value and insulation breakdown voltage were each 10 pieces, temperature change rate was measured for 2 pieces, average value was calculated and the results were obtained (Table 3). It was shown to.

[0045]

[Table 3]

Here, RunNo of (Table 3) is (Table 1)
RunNo. In addition, R in these tables
Samples marked with * in unNo are samples in which good results were not obtained for at least one of the evaluation items such as electrical characteristics and sinterability.

As is clear from (Table 1) and (Table 3),
When Dy ₂ O ₃ exceeds 1.3 moles per 100 moles of BaTiO _3, sinterability is slightly deteriorated by firing at 1250 ° C., so that the dielectric constant decreases. Tended to increase the temperature change rate. BaTi
If MgO exceeds 1.2 moles with respect to 100 moles of O ₃ , the dielectric constant will decrease and the dielectric loss will increase. If it is less than 0.1 moles, the reduction resistance during firing will be impaired. Increased, and the breakdown voltage and insulation resistance deteriorated.
When Mn ₃ O ₄ exceeds 0.12 mol with respect to 100 mol of BaTiO _3, a decrease in dielectric constant and an increase in dielectric loss are caused, and when less than 0.02 mol, insulation resistance and dielectric breakdown voltage rapidly deteriorate. . Further, the sintering aid component represented by the general formula of BaTiO ₃ 100 mol Ba _{0 .5} Ca _0.5 SiO ₃ exceeds 3.5 mol dielectric constant decreases, and becomes less than 0.5 mol The effect as a sintering aid was not obtained, and the densification by firing was incomplete, and the electrical characteristics were deteriorated over the whole.

On the other hand, the multilayer ceramic capacitor made of the reduction-resistant dielectric composition within the scope of the present invention is:
It has good sinterability and high dielectric constant.
Satisfies 7R characteristics and JIS B characteristics, shape is 321
It was possible to guarantee a rated voltage of 630 VDC in six sizes, and it was particularly promising as a chip-type multilayer ceramic capacitor for medium and high pressures having a high capacitance value.

As described above, according to the reduction-resistant dielectric composition of the present invention, a Ni internal electrode medium / high pressure chip having good sinterability and electric characteristics and capable of product development in a high capacity region. A multilayer ceramic capacitor can be realized.

Example 2 BaTiO ₃ powder as the main component (BET having a specific surface area of 2.5 m ² / g and Ba / T
i is 1.000) and the additives Dy ₂ O ₃ ,
Each powder of MgO and Mn ₃ O ₄ was prepared according to Run No.
A predetermined amount is weighed with an electronic balance based on the 18
Inner volume of 2100g containing φ ZrO ₂ ball is 28
Put into a 00CC ball mill.

Next, predetermined amounts of Ba and Ca acetates and TEOS (tetraethoxysilane) were added to RunNo. After weighing on an electronic balance based on 18 compositions, the acetate was 600 CC
Of pure water, and TEOS are separately dissolved in 900 CC of ethanol.

Then, the aqueous solution of acetate was poured into an ethanol solution, and 240 CC of 1N aqueous ammonia was added dropwise while stirring continuously to obtain a colloidal suspension composed of a sintering aid component.

Next, the colloidal suspension was charged into the ball mill and mixed at a rotation speed of 50 rpm for 20 hours. The mixture was filtered through a 150-mesh silk screen, poured into a stainless steel vat lined with a Teflon sheet, evaporated in a fume hood while evaporating the ethanol, covered with aluminum, and dried at 150 ° C. did. The dried mass was crushed in an alumina mortar, passed through a 32 mesh nylon sieve, and placed in an alumina crucible for 4 hours.
Heat treatment was performed under the conditions of 00 ° C./2 hours (temperature rising / falling rate: 200 ° C./H) to produce about 700 g of slurry powder.

Then, a multilayer ceramic capacitor element was manufactured in the same procedure as in Example 1. Next, after soldering terminals to both end surfaces of the multilayer ceramic capacitor element, the element body was embedded in an epoxy-based thermosetting resin to complete a mold-type multilayer ceramic capacitor.

FIG. 2 is a sectional view showing an embodiment of the ceramic electronic component of the present invention. As shown in FIG. 2, the molded multilayer ceramic capacitor of the present embodiment was formed by alternately laminating the BaTiO ₃ ceramic dielectric layer 23 and the internal electrode layers 22a, 22b, 22c containing Ni. A laminated body 21 is formed by laminating a BaTiO ₃ ceramic dielectric layer 23 as an ineffective layer above and below an effective layer serving as a capacitance acquisition layer. Internal electrode layers 22 b and 22 c are formed on both ends of the laminated body 21. A lower Ni-layer external electrode 24 electrically connected to the substrate was provided, and an upper Ag-layer external electrode 25 was provided thereon. Then, the laminate 21 embedded in the exterior material 26 made of a thermosetting resin or the like
Conductive terminals 27 are drawn out from both ends of the
It was configured such that it could be surface-mounted on a circuit board via a.

Next, the flexural strength of the molded multilayer ceramic capacitor of this example was measured. Deflection strength is an important evaluation item for judging the reliability of surface-mount electronic components. After soldering the DUT to a special printed circuit board, static bending is performed while applying a three-point bending with a special jig. The capacitance is measured, and the deflection width (mm) of the substrate at the time when the capacitance value sharply decreases is defined as the deflection strength. FIG. 4 shows a conceptual diagram of the deflection strength measurement. FIG. 4 is a conceptual diagram of deflection strength measurement. In general, cracks often occur in the DUT when the capacitance value sharply decreases. In the case of the mold-type multilayer ceramic capacitor of this example, even if the deflection width exceeded 15 mm, the capacitance value was stable without reduction. At the same time, in the case of the chip-type multilayer ceramic capacitor of Example 1, a sample under test in which the deflection width (mm) was 6 mm, the capacitance value sharply decreased, and cracks occurred was observed. The minimum standard for flexural strength is 2.0
mm is a level that does not cause any problem at all,
Clearly, the mold was better.

In the chip-type multilayer ceramic capacitor of the first embodiment, creepage leakage may occur due to dew condensation on the surface of the laminate with respect to an abnormal voltage that is out of specification. The multilayer ceramic capacitor has no such possibility and has high durability durability.

As described above, the multilayer ceramic capacitor of the present invention can realize high reliability and excellent surface mountability by being embedded in a thermosetting resin.

(Example 3) Run No. of Table 1 18
On the basis of the composition, a multilayer ceramic capacitor element was manufactured in the same procedure as in Examples 1 and 2. Next, after lead wires were soldered to both end surfaces of the multilayer ceramic capacitor element, the element body was covered with an epoxy-based exterior material to complete a lead-type multilayer ceramic capacitor.

FIG. 3 is a sectional view showing one embodiment of the ceramic electronic component of the present invention. The manufactured lead-type multilayer ceramic capacitor of the present embodiment was formed by alternately laminating BaTiO ₃ -based ceramic dielectric layers 33 and internal electrode layers 32a, 32b, and 32c containing Ni as shown in FIG. A laminate 31 is formed by laminating a BaTiO ₃ ceramic dielectric layer 33 as an ineffective layer above and below an effective layer serving as a capacitance acquisition layer. Internal electrode layers 32 b and 32 c are formed on both ends of the laminate 31. A lower Ni-layer external electrode 34 electrically connected to the above was provided, and an upper Ag-layer external electrode 35 was provided thereon. Then, conductive leads 37 are drawn out from both ends of the laminate 31 embedded in the exterior material 36 made of a thermosetting resin or the like, and can be soldered to a circuit board via the leads 37. Was configured to.

The lead-type multilayer ceramic capacitor of the present embodiment has no fear of creeping discharge due to abnormal voltage, and further, no mechanical stress such as bending is applied to the circuit board because the lead wire is soldered to the circuit board. It has an advantage in design.

(Example 4) Run No. of Table 1 18
A chip type multilayer ceramic capacitor having a shape of 3216 was formed by the same procedure as in Example 1 by using BaTiO ₃ powder in which the specific surface area value of BET and the molar ratio of Ba / Ti were changed based on the composition of Produced. B used
The specific surface area value of BET and the molar ratio of Ba / Ti of the aTiO ₃ powder are shown in (Table 4).

[0063]

[Table 4]

Then, the dielectric constant, the rate of temperature change of capacitance and the dielectric breakdown voltage of the manufactured chip-type multilayer ceramic capacitor were evaluated. The dielectric constant was measured in the same manner as in Example 1. First, the capacitance (Cap) was measured using a YHP LCR meter 4.
After measuring under a signal voltage of 1 V / 1 KHz using 284A, it was calculated from the effective layer thickness and the counter electrode area inside the multilayer ceramic capacitor. Dielectric breakdown voltage (BD
V) was measured for DC breakdown voltage in silicone oil using a Kikusui Electronics pressure gauge. Temperature change rate of capacitance (Cap
-TC) was measured within the range of -55 to + 125 ° C by connecting a YHP LCR meter 4284A to the thermostat. The capacitance was measured for 20 pieces each, and the dielectric constant was calculated from the average value. In addition, each of 10 dielectric breakdown voltages and two temperature change rates of capacitance was measured, and the average value was calculated. The results are shown in (Table 5). Here, RunNo in (Table 5) corresponds to RunNo in (Table 4). In addition, those marked with * for RunNo in these tables are samples for which good results were not obtained for at least one of the above evaluation items.

[0065]

[Table 5]

As is clear from Tables 4 and 5, the specific surface area of the BaTiO ₃ powder used was 3.0 in BET.
When it exceeds m ² / g, the dielectric constant decreases, and the temperature change rate of the capacitance increases at the same time, deviating from the EIA standard X7R characteristic. When it is less than 2.0 m ² / g, the dielectric breakdown voltage decreases and the designed rated voltage Guarantee tended to be difficult. Further, when the molar ratio of Ba / Ti exceeds 1.007, the dielectric constant tends to decrease and the dielectric breakdown voltage tends to decrease, and when it is less than 0.993, the temperature change rate of the capacitance tends to increase. Was. Further, when the molar ratio of Ba / Ti is less than 0.993, the reduction resistance is impaired during firing in a reducing atmosphere, and the insulation resistance value, which is an electrical property other than the above properties, tends to deteriorate. The molar ratio is 1.0
If it exceeds 07, sintering tends to be difficult to proceed during firing in a reducing atmosphere, in addition to deterioration in electrical characteristics. FIG. 5 shows the BET specific surface area value of BaTiO ₃ powder and Ba Ba within the range of the present invention.
/ Ti molar ratio is shown. FIG. 5 is a graph showing the BET specific surface area value and the Ba / Ti molar ratio of BaTiO ₃ powder within the range of the present invention. By using a BaTiO ₃ powder within this range, it has excellent reduction resistance and sinterability, has electrical characteristics comparable to those for medium and high pressures, and has a high capacity region as a base metal internal electrode multilayer ceramic capacitor. Thus, it is possible to obtain a reduction-resistant dielectric composition having a high dielectric constant that enables commercial product development.

[0067]

As described above, according to the present invention, the specific surface area value of BET is in the range of 2.0 to 3.0 m ² / g, and the molar ratio of Ba / Ti is 0.993 to 1 0.0007 as a main component, BaTiO ₃ , at least as an additive, a compound of Dy oxide or a compound which becomes a Dy oxide by firing, an oxide of Mg or Mg by firing.
A compound which becomes an oxide of Mn, an oxide of Mn or a compound which becomes an oxide of Mn by firing, and is represented by a general formula of Ba _1-X Ca _X SiO ₃ at least as a sintering aid, wherein X is 0 ≦ It contains a component comprised in the range of X ≦ 1, and contains Ca, Ba and Si in order to mix the Ba _{1 -X} Ca _X SiO ₃ component with the powder of the main component and the additive in a solution state. The composition is uniformly coated around the BaTiO ₃ particles, which are the main component, and has a very controlled crystal particle size and dense structure in which the sintering aid component is uniformly dispersed without local abnormal reaction during firing. A reducible dielectric composition that can be formed is obtained. Further, by constituting the ceramic dielectric layer with the above-mentioned reduction-resistant dielectric composition,
It has good electrical characteristics and durability reliability, and has a high dielectric constant that enables product development in high-capacity areas. Mainly for medium and high pressures, it is possible to design circuits that meet the needs of users by taking advantage of their respective characteristics. The effect of being able to manufacture ceramic electronic components typified by chip-type, mold-type and lead-type multilayer ceramic capacitors can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a ceramic electronic component of the present invention.

FIG. 2 is a sectional view showing one embodiment of the ceramic electronic component of the present invention.

FIG. 3 is a sectional view showing one embodiment of the ceramic electronic component of the present invention.

FIG. 4 is a conceptual diagram of deflection strength measurement.

FIG. 5 is a graph showing the BET specific surface area value and the Ba / Ti molar ratio of BaTiO ₃ powder within the range of the present invention.

[Explanation of symbols]

 11, 21, 31 Laminated body 12a, 22a, 32a Internal electrode layer 12b, 22b, 32b Internal electrode layer 12c, 22c, 32c Internal electrode layer 13, 23, 33 Ceramic dielectric layer 14, 24, 34 Ni-based lower external electrode 15, 25, 35 Ag upper layer external electrode 26 Exterior material 27 Terminal 36 Exterior material 37 Lead wire 38 Solder

Continued on the front page (72) Inventor Masuhiro Yamamoto 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F-term (reference) 4G031 AA03 AA04 AA06 AA07 AA11 AA19 AA30 AA39 BA09 BA26 CA03 CA04 CA08 GA02 GA04 5E001 AB03 AE04 5G303 AA01 AB06 AB11 AB14 AB20 BA12 CA01 CB03 CB17 CB18 CB30 CB35 CB41 CC03 DA06

Claims (8)

[Claims] 1. A BET having a specific surface area of 2.0 to 3.0 m ^2.
/ G and the molar ratio Ba / Ti is 0.9.
BaTi which is the main component in the range of 93 to 1.007
Against O _3, containing a metal oxide or a compound forming an oxide of the metal by firing as an additive, a reduction resistant dielectric, characterized by containing a compound of the SiO ₂ system as a sintering aid Composition. 2. A BET having a specific surface area of 2.0 to 3.0 m ^2.
/ G and the molar ratio Ba / Ti is 0.9.
BaTi which is the main component in the range of 93 to 1.007
With respect to O ₃ , an oxide of Dy or a compound which becomes an oxide of Dy by firing, an oxide of Mg or a compound which becomes an oxide of Mg by firing, an oxide of Mn or an oxidation of Mn by firing Ba _1-x Ca _x SiO ₃ at least as a sintering aid
Wherein X comprises a component in the range of 0 ≦ X ≦ 1. 3. A BET having a specific surface area of 2.0 to 3.0 m ^2.
/ G and the molar ratio Ba / Ti is 0.9.
BaTi which is the main component in the range of 93 to 1.007
O to ₃ 100 mol, 0.2 to 1.3 mol of compounds that become oxides oxide Dy ₂ O ₃ in terms of an oxide or firing Dy as an additive, oxide or oxides by firing Mg Is 0.1 to 0.1% in terms of oxide MgO.
It contains 0.02 to 0.12 mol of an oxide of Mn or a compound which becomes an oxide by firing in terms of oxide Mn ₃ O ₄ , and Ba ₁ -x Ca _x SiO ₃ as a sintering aid. Wherein X is in the range of 0 ≦ X ≦ 1 in an amount of 0.5 to 3.5 mol. 4. The component represented by the general formula of Ba _{1 -X} Ca _X SiO ₃ wherein X is in the range of 0 ≦ X ≦ 1 is an aqueous solution of Ca and Ba acetate and a metal alkoxide ethanol of Si. 4. The reduction-resistant dielectric composition according to claim 2, wherein ammonia water is added dropwise to the mixed solution while stirring the mixed solution with the solution. 5. The method according to claim 1, wherein the first plurality of ceramic dielectric layers have N
a base having an effective layer provided with an internal electrode layer made of an alloy containing i or Ni as a main component and an ineffective layer formed of a second plurality of ceramic dielectric layers; A chip-type ceramic electronic component provided with a pair of external electrodes electrically connected to the internal electrode layer, wherein the ceramic dielectric layer is provided.
A ceramic electronic component comprising the reduction-resistant dielectric composition according to any one of Items 1 to 4. 6. The method according to claim 1, wherein N is between the first plurality of ceramic dielectric layers.
a base having an effective layer provided with an internal electrode layer made of an alloy containing i or Ni as a main component and an ineffective layer formed of a second plurality of ceramic dielectric layers; And a pair of external electrodes electrically connected to the internal electrode layer, and terminals respectively connected to the external electrodes, wherein the base and the external electrodes are embedded in a resin. 5. A component, wherein said ceramic dielectric layer is formed of any one of claims 1 to 4.
7. A ceramic electronic component, comprising the reduction-resistant dielectric composition according to item 1. 7. The method according to claim 1, wherein the first plurality of ceramic dielectric layers have N
a base having an effective layer provided with an internal electrode layer made of an alloy containing i or Ni as a main component and an ineffective layer formed of a second plurality of ceramic dielectric layers, and extending from both end portions to side portions of the base. A lead-type ceramic comprising a pair of external electrodes electrically connected to the internal electrode layer, and lead wires respectively connected to the external electrodes, wherein the base and the external electrodes are covered with a resin. 5. An electronic component, wherein the ceramic dielectric layer is formed of any one of claims 1 to 4.
A ceramic electronic component comprising the reduction-resistant dielectric composition described in 1 above. 8. The ceramic electronic component according to claim 5, wherein the external electrode has a two-layer structure of an upper layer and a lower layer, and the lower layer is provided only on an end face of the base.