JPH05217798A - Ceramic capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve specific inductive capacity, to enhance a CR product at a high temperature, to decrease in size and to increase in capacity a ceramic capacitor and to increase reliability at a high temperature by forming a composition of dielectric ceramic composition for constituting a dielectric layer of the capacitor of a mixture of a basic component and additive components having special pts.wt. and special component relationship. CONSTITUTION:A dielectric ceramic composition is formed by baking a mixture of 100.0 pts.wt. of basic component and 0.2-5.0 pts.wt. of additive components. The basic component is formed of a formula (where R, R' are rare earth elements, and alpha, x, y, z, k are numeric values for satisfying 0.002<=alpha<=0.04, 0<=x<=0.27, 0.05<=y<=0.26, 0.5<=z<=0.9, 1.00<=k<=1.04). The additive components contain Li2O, SiO2 and MO (where the MO is one or two or more oxides selected from BaO, SrO, CaO, MgO and ZnO). Incidentally, composition ranges of the Li2O, the SiO2 and the MO are specified.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-layer or multi-layered porcelain capacitor having one or more dielectric porcelain layers sandwiched by internal electrodes, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a laminated porcelain capacitor is formed by printing an unsintered porcelain sheet (green sheet) made of dielectric porcelain raw material powder with a conductive paste containing a noble metal such as platinum or palladium as a main component in a desired pattern. It is manufactured by stacking a plurality of these unsintered porcelain sheets, press-bonding them, and firing them at 1300 ° C to 1600 ° C in an oxidizing atmosphere.

Here, the conductive paste containing a precious metal such as platinum or palladium as a main component is used when the conductive paste containing a precious metal such as platinum or palladium as a main component is used. , Laminated porcelain capacitors in an oxidizing atmosphere at 1300 ° C-1600 ° C
The conductive paste does not oxidize even when fired at a high temperature,
This is because a desired internal electrode can be obtained. However, since the noble metal such as platinum or palladium is an expensive material, the conventional multilayer ceramic capacitor has a problem of high cost.

In order to solve this problem, Japanese Patent Publication No. 60-20851 relating to the applicant of the present invention discloses {(Ba _x Ca _y Sr _z ) O} _k (Ti _n Zr _1-n ) O. _{2 as} a basic component, Li ₂ O, SiO ₂ and MO (where MO is BaO,
Disclosed is a dielectric ceramic composition containing an additive component composed of one or more oxides selected from CaO and SrO.

Further, in Japanese Patent Laid-Open No. 61-147404, a basic component consisting of {(Ba _1-xy Ca _x Sr _y ) O} _k (Ti _1-z Zr _z ) O ₂ and B ₂ O ₃ There is disclosed a dielectric ceramic composition containing SiO _2, and an additive component consisting of Li ₂ O.

Further, in Japanese Patent Laid-Open No. 61-147405, a basic component consisting of {(Ba _1-xy Ca _x Sr _y ) O} _k (Ti _1-z Zr _z ) O ₂ and B ₂ O ₃ are disclosed. There is disclosed a dielectric ceramic composition containing SiO ₂ and an additive component made of SiO ₂ .

Further, Japanese Patent Laid-Open No. 61-147406 discloses a basic component consisting of {(Ba _1-xy Ca _x Sr _y ) O} _K (Ti _1-z Zr _z ) O ₂ and B ₂ O ₃ And SiO ₂ and MO (where MO is Ba
Disclosed is a dielectric ceramic composition containing an additive component consisting of one or more oxides selected from O, CaO and SrO.

The dielectric ceramic composition disclosed in each of these publications can be obtained by firing at a relatively low temperature of 1200 ° C. or lower in a reducing atmosphere, but its relative dielectric constant ε is 5000 or more, resistivity ρ is 1 × 1
It is 0 ⁶ MΩ · cm or more.

[0009]

By the way, in recent years, there has been a great deal of progress in increasing the density of electronic circuits, and there is a strong demand for miniaturization of laminated ceramic capacitors, and the laminated ceramic capacitors are used as electrical components for automobiles and the like. Therefore, there is a very strong demand for the reliability of the laminated ceramic capacitor at high temperatures.

Therefore, the relative permittivity ε of the dielectric ceramic composition forming the dielectric layer of the laminated ceramic capacitor and the high temperature CR
It has been desired to develop a porcelain capacitor having a better product than the dielectric porcelain composition disclosed in each of the above publications without deteriorating other electrical characteristics.

Therefore, although the object of the present invention is obtained by firing at a temperature of 1200 ° C. or lower in a non-oxidizing atmosphere, the ratio of the dielectric ceramic composition constituting the dielectric layer is Dielectric constant ε is 7,000 or more, dielectric loss t
anδ of 2.5% or less, resistivity ρ of 1 × 10 ⁶ MΩ · c
It is an object of the present invention to provide a porcelain capacitor having a CR product at 150 ° C. of m or more and 1000 F · Ω or more, which is more excellent in electrical characteristics than conventional ones, and a manufacturing method thereof.

[0012]

A porcelain capacitor according to the present invention comprises one or more dielectric porcelain layers made of a dielectric porcelain composition, and two or more internal electrodes sandwiching the dielectric porcelain layer. In a porcelain capacitor provided with, the dielectric porcelain composition comprises 100.0 parts by weight of a basic component and 0.
2 to 5.0 parts by weight of a mixture with an additive component is calcined, and the basic component is (1-α) {(Ba _1-x Ca _x ) O} _k (Ti _1-y Zr _y ). O ₂ + α (R _1-z R ′ _Z ) O _3/2 (wherein R is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu, R ′
Is Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or more elements selected from Tm and Lu, α, x, y, z, k are 0.002 ≦ α ≦ 0.04 0 ≦ x ≦ 0.27 0.05 ≦ y ≦ 0 .26 0.5 ≦ z ≦ 0.9 1.00 ≦ k ≦ 1.04), wherein the additive components are Li ₂ O and S.
iO ₂ and MO (where MO is BaO, SrO, CaO,
1 or 2 or more kinds of oxides selected from MgO and ZnO), and the composition range of the Li ₂ O, the SiO ₂ and the MO is a triangle diagram showing these compositions in mol%. Li ₂ O is 1 mol%, the SiO ₂ is 80 mol%, the MO is 19 mol%, and the first point A indicates a composition, the Li ₂ O is 1 mol%, and the SiO ₂ is 39 mol%.
Second point B showing a composition of mol% and the MO is 60 mol%
And a third point C showing a composition in which the Li ₂ O is 30 mol%, the SiO ₂ is 30 mol%, and the MO is 40 mol%.
And a fourth point D showing a composition in which the Li ₂ O is 50 mol%, the SiO ₂ is 50 mol%, and the MO is 0 mol%,
Within a region surrounded by five straight lines connecting the fifth point E indicating the composition of 20 mol% of Li ₂ O, 80 mol% of SiO _{2 and} 0 mol% of MO in this order. Is.

In the composition of the basic component, (R
_1-z R ′ _Z ) O _3/2 ratio, that is, the value of α is 0.002 ≦ α
The range of ≦ 0.04 is because the value of α is 0.002 ≦ α
If ≦ 0.04, desired electrical characteristics can be obtained, but if less than 0.002, ta
nδ is significantly deteriorated, and the resistivity ρ is also 1 × 10 ³ MΩ · cm.
If it is less than 0.04 and exceeds 0.04, a dense sintered body cannot be obtained even if the firing temperature is 1250 ° C.

The ratio of the number of Ca atoms in the compositional formula of the basic component, that is, the value of x is set to 0 ≦ x ≦ 0.27, when the value of x is 0 ≦ x ≦ 0.27. , A sintered body having desired electrical characteristics can be obtained, but 0.2
When it exceeds 7, the firing temperature for obtaining a dense sintered body becomes as high as 1250 ° C., and the relative dielectric constant ε _s becomes less than 7,000.

Further, the ratio of the number of Zr atoms in the composition formula of the basic component, that is, the value of y is set to 0.05 ≦ y ≦ 0.2.
The reason for setting 6 is that when the value of y is 0.05 ≦ y ≦ 0.26, a sintered body having desired electrical characteristics can be obtained, but when it is out of this range, , Relative permittivity ε _s
Is less than 7,000.

The ratio of the number of atoms of R in the composition formula of the basic component, that is, the value of z is set to 0.5 ≦ z ≦ 0.9, because the value of z is 0.5 ≦ z ≦ 0. In the case of 0.9, a sintered body having desired electrical characteristics can be obtained,
When it becomes less than 0.5 or exceeds 0.9, the high temperature CR product falls below 1000 F · Ω,
This is because desired electrical characteristics cannot be obtained.

The R components La, Ce, Pr, Nd,
Pm, Sm and Eu work in much the same way, using one or more selected from these gives similar results. The R'components of Sc, Y, Gd, D
Since y, Ho, Er, Yb, Tb, Tm and Lu work almost the same, even if one selected from these is used,
Alternatively, the same result can be obtained by using two or more.

[(Ba _1-x Ca _x ) in the composition formula of the basic component
The ratio of O}, that is, the value of k is 1.00 ≦ k ≦ 1.04
The reason is that when the value of k is 1.00 ≦ k ≦ 1.04, a sintered body having desired electrical characteristics can be obtained, but when it is less than 1.00 Has a tan δ of 2.5% or more and a resistivity ρ of 1 × 10 ⁴ MΩ · cm
This is because if it is less than 1.04, the high temperature CR product is significantly deteriorated, and if it exceeds 1.04, a dense sintered body cannot be obtained even by firing at 1250 ° C.

Among the basic components, a very small amount of MnO ₂ (preferably 0.05) is used as long as the object of the present invention is not impaired.
(About 0.1% by weight) may be added to improve the sinterability. Moreover, you may add another substance as needed. Further, as a starting material for obtaining the basic components, oxides other than those shown in the examples may be used,
Hydroxides or other compounds may be used.

Next, the addition amount of the additive component is 0.2 to 5.0 parts by weight with respect to 100 parts by weight of the basic component.
When the added amount of the additive component is within this range, 1190 to
A sintered body having desired electrical characteristics can be obtained by firing at 1200 ° C., but if it is less than 0.2 parts by weight, a dense sintered body cannot be obtained even if the firing temperature is 1250 ° C. If it exceeds 5.0 parts by weight, the relative permittivity ε _s will be less than 7,000.

In the triangular diagram showing the composition of Li ₂ O, SiO ₂ and MO in mol%, the composition of the additive component is within a range surrounded by five straight lines connecting the points A to E in this order. The reason is that if the composition of the additive component is within this range, a sintered body having desired electrical characteristics can be obtained, but if the composition of the additive component is outside this range, 1250 is obtained.
This is because a dense sintered body cannot be obtained by firing at ℃. The MO component is BaO, SrO, CaO, Mg.
Any one of O and ZnO may be used, or an appropriate ratio may be used.

Next, a method of manufacturing a porcelain capacitor according to the present invention comprises the steps of preparing a mixture of unsintered porcelain powder consisting of the above-mentioned basic components and additive components, and an unsintered porcelain consisting of the mixture. Forming a sheet, forming a laminate in which the green ceramic sheet is sandwiched by at least two or more conductive paste films, heat treating the laminate in a non-oxidizing atmosphere, And a step of heat-treating the heat-treated laminate in an oxidizing atmosphere.

Here, the non-oxidizing atmosphere may be not only a reducing atmosphere such as H ₂ or CO but also a neutral atmosphere such as N ₂ or Ar. The temperature of the heat treatment in the non-oxidizing atmosphere may be lower than the firing temperature in the non-oxidizing atmosphere, and is preferably in the range of 500 to 1000 ° C.

The oxidizing atmosphere is not limited to the atmospheric atmosphere, and for example, an atmosphere having a low oxygen concentration such as a mixture of N ₂ and O ₂ of several ppm can be used. You can It is necessary to variously change the temperature or the oxygen concentration of the atmosphere in consideration of the oxidation of the electrode material (such as nickel) and the oxidation of the dielectric ceramic layer. Although the temperature of this heat treatment was set to 600 ° C. in the examples described later, the temperature is not limited to this temperature.

In the examples described later, the heat treatment in the non-oxidizing atmosphere and the heat treatment in the oxidizing atmosphere are carried out in one continuous firing profile. It is also possible to perform the heat treatment step in an oxidizing atmosphere in separate steps.

Further, although the Zn electrode is used as the external electrode in the embodiment, it is needless to say that Ni, Ag, Cu or the like can be used by selecting the baking condition of the electrode. It is also possible to apply the external electrode to the end surface of the unfired laminate and simultaneously fire the laminate and fire the external electrode.

The present invention is of course applicable to general single-layer porcelain capacitors other than laminated porcelain capacitors.

[0028]

Example First, the sample No. The case of 1 will be described. Preparation of Basic Components Each of the compounds shown in Table 1 was weighed and put in a pot mill together with a plurality of alumina balls and 2.5 liters of water, and mixed by stirring for 15 hours to obtain a mixture.

[0029]

[Table 1]

Here, the weight (g) of each compound in Table 1 is
Compositional formula of basic components (1-α) {(Ba _1-x Ca _x ) O} _k (Ti _1-y Zr _y ) O ₂ + α (R _1-z R ′ _Z ) O _3/2 (however, R R'is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu.
Is Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or more elements selected from Tm and Lu) ... (1) The first term {(Ba _1-x Ca _x ) O} _k (Ti _1-y Zr _y ) O ₂ is {(Ba
_0.93 Ca _0.07 ) O} _1.01 (Ti _0.85 Zr _0.15 ) O ₂ It is a calculated value.

Next, this raw material mixture was placed in a stainless pot and dried at 150 ° C. for 4 hours using a hot air drier, the dried mixture was roughly crushed, and the roughly crushed mixture was used in a tunnel furnace. About 1200 ℃ in the atmosphere
Calcination was performed for 2 hours to obtain the component powder (first basic component) of the first item in the composition formula (1) of the basic component.

Then, the sample No. 1, 98 parts by mole (984.81 g) of the powder of the first basic component and 2 parts by mole (15 .19 g, of which Dy ₂ O
₃ of 10.88 g and CeO ₂ of 4.31 g) and a powder of the second basic component (component of the second term in the composition formula (1) of the basic component) are stirred for 15 hours in a wet pot mill and dried at 150 ° C. , 1000 g of the basic component was obtained.

Preparation of Additive Components In addition, the compounds shown in Table 2 were weighed, and these compounds were placed in a polyethylene pot, and a plurality of alumina balls and 30 balls were added.
The mixture was added with 0 ml of alcohol and mixed for 10 hours with stirring to obtain a mixture.

[0034]

[Table 2]

Here, the weight (g) of each compound in Table 2 is
Li ₂ O is 1 mol%, SiO ₂ is 80 mol%, MO is 1
9 mol% {BaO (3.8 mol%) + CaO (9.5 mol%) +
It is a value obtained by calculation so as to have a composition of MgO (5.7 mol%)}. Also, among MO, BaO, CaO and M
The ratio of gO is 20 mol% of BaO and 5 of CaO.
0 mol% and MgO are 30 mol%.

Next, the above mixture is heated to about 10% in the atmosphere.
It was calcined at a temperature of 00 ° C. for 2 hours, placed in an alumina pot together with a plurality of alumina balls and 300 ml of water, pulverized for 15 hours, and then dried at 150 ° C. for 4 hours to obtain an additive component of the above composition. A powder was obtained.

Preparation of Slurry Next, 100 parts by weight (1000 g) of the above basic components,
Into a ball mill, 2 parts by weight (20 g) of the above-mentioned additional components were added, and further, 15% by weight of an organic binder and 50% by weight of water were added to the total weight of these basic components and additional components, and these were mixed. Then, it was pulverized to obtain a slurry as a raw material of the dielectric ceramic composition. Here, the organic binder used was an aqueous solution of acrylic acid ester polymer, glycerin and condensed phosphate.

Formation of Unsintered Porcelain Sheet Next, the above slurry was placed in a vacuum defoaming machine for defoaming treatment,
The defoamed slurry is applied on a polyester film with a reverse coater to a predetermined thickness, and the applied slurry is applied together with the polyester film to 1
It was heated at 00 ° C. and dried to obtain a long unsintered porcelain sheet having a thickness of about 25 μm. Then, this long unsintered porcelain sheet was cut to obtain a 10 cm square unsintered porcelain sheet.

Preparation and Printing of Conductive Paste Also, 10 g of nickel powder having an average particle size of 1.5 μm, 0.9 g of ethyl cellulose and 9.1 g of butyl carbitol.
Put what was dissolved in a stirrer and stir for 10 hours,
A conductive paste for internal electrodes was obtained.

Then, 50 patterns (length 14 mm, width 7 mm) made of this conductive paste were formed on one surface of the green ceramic sheet by a screen printing method and dried.

Lamination of Unsintered Porcelain Sheets Next, two unsintered porcelain sheets were laminated with the side on which the pattern made of the conductive paste was formed facing up. At the time of this lamination, the pattern made of the conductive paste was shifted by about half in the longitudinal direction between the adjacent upper and lower unsintered porcelain sheets. Then, four unsintered porcelain sheets each having a thickness of 60 μm were laminated on each of the upper and lower surfaces of the laminated body as described above to obtain a laminated body.

Pressing and Cutting of Laminate Next, at a temperature of about 50 ° C., a load of about 40 tons is applied from the thickness direction to the laminate to form a green porcelain sheet constituting the laminate. We crimped each other. Then, this laminate was cut into a lattice shape to obtain 50 laminate chips.

Firing of Laminated Chip Next, the laminated chip is placed in a furnace capable of atmospheric firing, the atmosphere in the furnace is raised to 600 ° C. at a rate of 100 ° C./h, and unsintered. The organic binder in the porcelain sheet was burned off.

After that, the atmosphere in the furnace was changed from the air atmosphere to the reducing atmosphere {H ₂ (2% by volume) + N ₂ (98% by volume)}, and the temperature in the furnace was changed from 600 ° C. to 1150 ° C. to 100 ° C.
The temperature is raised at a rate of ℃ / h, the temperature of 1150 ℃ is maintained for 3 hours, and then the temperature is lowered at a rate of 100 ℃ / h, the atmosphere in the furnace is changed to an atmospheric atmosphere (oxidizing atmosphere), and 600 ℃
The temperature was maintained for 30 minutes for oxidation treatment, and then cooled to room temperature to obtain a laminated sintered body chip.

Formation of External Electrodes Next, among the opposite side surfaces of this laminated sintered body chip,
By forming a pair of external electrodes on the side surfaces where the ends of the internal electrodes are exposed, three layers of dielectric ceramic layers 12, as shown in FIG.
A laminated ceramic capacitor 10 was obtained in which a pair of external electrodes 16, 16 were formed at the ends of a laminated sintered body chip 15 consisting of 12, 12 and two layers of internal electrodes 14, 14.

Here, the external electrode 16 is formed by applying a conductive paste composed of zinc, glass frit and vehicle to the side surface, drying the conductive paste, and then drying the conductive paste in the atmosphere at 550. The zinc electrode layer 18 is formed by baking at a temperature of ℃ for 15 minutes.
8 was formed by electroless plating, and then a Pb—Sn solder layer 22 was formed on the copper layer 20 by electroplating.

The thickness of the dielectric ceramic layer 12 of the laminated ceramic capacitor 10 is 0.02 mm, and the pair of internal electrodes 1
The facing area of 4, 14 is 5 mm × 5 mm = 25 mm ² . The composition of the dielectric ceramic layer 12 after sintering is substantially the same as the composition of the mixture of the basic component and the additive component before sintering.

Measurement of Electrical Characteristics Next, the electrical characteristics of the laminated ceramic capacitor 10 are measured,
When the average value was obtained, as shown in the right column of Table 3, the relative permittivity ε _s was 15900, tan δ was 1.4%,
The resistivity ρ was 3.72 × 10 ⁶ MΩ · cm, and the high temperature CR product was 1850 F · Ω.

The electrical characteristics were measured as follows. (A) The relative permittivity ε _s is measured by measuring the capacitance under the conditions of a temperature of 20 ° C., a frequency of 1 kHz, and a voltage (effective value) of 1.0 V, and the measured value and the facing area of the pair of internal electrodes 14, 14. (25
mm ² ) and the thickness (0.02 mm) of the dielectric ceramic layer 12 between the pair of internal electrodes 14 and 14. (B) Dielectric loss tan δ (%) is the relative permittivity ε
It was measured under the same conditions as in the case of _s measurement of. (C) The resistivity ρ (MΩ · cm) is D at a temperature of 20 ° C.
After applying C100V for 1 minute, a pair of external electrodes 1
The resistance value between Nos. 6 and 16 was measured, and calculated based on the measured value and the dimension. (D) High temperature CR product (F · Ω) is 150 ° C and frequency is 1
Capacitance was measured under the conditions of kHz and voltage (effective value) of 1.0 V, and after applying DC 100 V for 1 minute, the resistance value [MΩ] between the pair of external electrodes 16 and 16 was measured,
It was calculated.

As described above, the sample No. The sample No. 1 has been described. Regarding Nos. 2 to 87, the compositions of the basic component and the additive component were changed as shown in the left columns of Tables 3 to 3, and the firing temperature in the reducing atmosphere was changed as shown in the right columns of Tables 3 to 3. Others are sample No. A laminated porcelain capacitor was prepared by the same method as that of No. 1, and the electrical characteristics were measured by the same method. Sample No. The electrical characteristics of 2-87 are shown in Table 3.
~ It became as shown in the right column of Table 3.

In Tables 3 to 3, in the column of 1-α, {(Ba _1-x Ca _x ) in the first term of the composition formula of the basic component is shown.
The ratio of O} _k (Ti _1-y Zr _y ) O ₂ is in the column 1-x, the ratio of the number of Ba atoms in the first term of the composition formula of the basic component, and the column x is the basic component. The ratio of the number of Ca atoms in the first term of the composition formula, the ratio of the number of Ti atoms in the first item of the composition formula of the basic component in the 1-y column, and the composition formula of the basic component in the y column. The ratio of the number of Zr atoms in the first term of, the k column is the ratio of {(Ba _1-x Ca _x ) O} in the first term of the composition formula of the basic component, and the α column is the basic component. (R in the second term of the composition formula of
_1-z R _'Z) ratio of O _3/2 is 1-z section ratio of the number of atoms of R in the second term of the formula of the basic component is of the composition formula of the basic component in the column of the z The ratio of the number of atoms of R'in the second term of is shown.

In addition, in the columns of the contents of the added components in Tables 3 to 3, the column of the added amount by weight shows the parts by weight of the added component relative to 100 parts by weight of the basic component, and the column of the composition shows L.
The proportions of i ₂ O, SiO ₂ and MO are given in mol%, M
In the column of O content, the proportions of BaO, SrO, CaO, MgO and ZnO are shown in mol%.

Sample No. Nos. 1 to 23 clarify the proper range of glass as an additive component, and sample No. 24-3
No. 5 clarifies the proper range of the addition amount of the additive component,
o. 36 to 47 clarified the appropriate range of w, which is the ratio of the number of Ca atoms, and the sample No. Nos. 48 to 57 clarified the appropriate range of the y value, which is the ratio of the number of Zr atoms, and the sample No.
58 to 67 clarified the appropriate range of z, which is the ratio of the number of atoms of R ', and the sample No. 68 to 77 clarified the appropriate range of α, which is the ratio of (R _1-z R ′ _Z ) O _3/2 , and the sample No. 78
~ 87 clarifies an appropriate range of k which is a ratio of {(Ba _1-x Ca _x ) O}.

[0054]

[Table 3]

[0055]

[Table 3]

[0056]

[Table 3]

[0057]

[Table 3]

[0058]

[Table 3]

[0059]

[Table 3]

As is clear from Tables 3 to 3, according to the sample according to the present invention, 12 in a non-oxidizing atmosphere is used.
When fired at a temperature of 00 ° C. or lower, the relative dielectric constant ε _s is 7,000 or more, the dielectric loss tan δ is 2.5% or less, and the resistivity ρ is 1 × 10.
⁶ MΩ · cm or more, CR product at 150 ° C is 1000
It is possible to obtain a porcelain capacitor provided with a dielectric porcelain composition having electrical characteristics of F · Ω or more.

On the other hand, in No. 11-16,24,2
9, 30, 35, 41, 47, 48, 52, 53, 5
7,58,67,68,72,73,77,78,8
According to the samples Nos. 2, 83 and 87, it is not possible to obtain a porcelain capacitor having desired electric characteristics. Therefore,
These No. Samples are outside the scope of the present invention.

Next, the reasons for limiting the composition range of the dielectric porcelain composition used in the porcelain capacitor according to the present invention are shown in Tables 3 to 3. A description will be given with reference to 1 to 87.

First, the ratio of the number of Ca atoms in the composition formula of the basic component, that is, the value of x will be described. The value of x is the sample No. As shown in 40 and 46, 0.27
In the case of No. 1, a sintered body having desired electrical characteristics can be obtained. 41 and 47,
In the case of 0.30, the firing temperature for obtaining a dense sintered body is as high as 1250 ° C., and the relative dielectric constant ε _s is also less than 7,000. Therefore, the upper limit of the value of x is 0.27.

Sample No. 37-40, 43-46
As shown in Fig. 5, Ca has a function of flattening the temperature characteristics and a function of improving the resistivity ρ, but the value of x is
o. As shown in 36 and 42, it is possible to obtain a sintered body having desired electrical characteristics even if it is zero. Therefore, the lower limit of the value of x is zero.

Next, the ratio of the number of Zr atoms in the composition formula of the basic component, that is, the value of y will be described. The value of y is the sample No. As shown in 49 and 54, 0.05
In the case of No. 1, a sintered body having desired electrical characteristics can be obtained. As shown in 48 and 53,
In the case of 0.03, the relative dielectric constant ε _s is less than 7,000. Therefore, the lower limit of the value of y is 0.05.

On the other hand, the value of y is the sample No. 51 and 56
As shown in FIG. 2, in the case of 0.26, a sintered body having desired electrical characteristics can be obtained. 52 and 57
As shown in, the relative permittivity ε _s is 7 when 0.29.
It will be less than 000. Therefore, the upper limit of the value of y is 0.26.

Next, the ratio of the second term of the formula of the basic component _{(R 1-z R 'z} ), i.e., the value of α will be described. The value of α is the sample No. As shown in Nos. 69 and 74, in the case of 0.002, it is possible to obtain a sintered body having desired electrical characteristics. 68 and 73, in the case of 0.001, the dielectric loss tan
δ is significantly deteriorated, the resistivity ρ is less than 1 × 10 ³ MΩ · cm, and the high temperature CR product is significantly deteriorated. Therefore,
The lower limit of the value of α is 0.002.

On the other hand, the value of α is the sample No. 71 and 76
As shown in No. 4, when 0.04, a sintered body having desired electrical characteristics can be obtained. As shown in 72 and 77, in the case of 0.06, a dense sintered body cannot be obtained even if the firing temperature is 1250 ° C. Therefore, the upper limit of the value of α is 0.04.

Next, the ratio of the number of atoms of R'in the second term of the composition formula of the basic component, that is, the value of z will be described. The value of z is the sample No. In the case of 0.5 as shown in No. 59, it is possible to obtain a sintered body having desired electrical characteristics. As shown in 58, in the case of 0.40, the high temperature CR product becomes less than 1000 F · Ω. Therefore, the lower limit of z is 0.5.

On the other hand, the value of z is the sample No. As shown in 66, when 0.9, a sintered body having desired electrical characteristics can be obtained. As shown in 67, when 0.95, the high temperature CR product is less than 1000 F · Ω. Therefore, the upper limit of the value of z is 0.9.

The R component La, Ce, Pr, Nd,
Pm and Eu work in much the same way, using one or more selected from them with similar results. Also, Sc, Y, Dy, Ho,
Er and Yb work in much the same way, using one or more selected from these to obtain similar results.

Next, in the composition formula of the basic component, {(Ba
The ratio of _1-x Ca _x ) O}, that is, the value of k will be described.
The value of k is the sample No. As shown in 79 and 84, 1.
In the case of No. 00, it is possible to obtain a sintered body having desired electrical characteristics. As shown in 78 and 83, in the case of 0.99, tan δ becomes 2.5% or more, the resistivity ρ becomes significantly lower than 1 × 10 ⁴ MΩ · cm, and the high temperature CR product becomes large. Worsens. Therefore, the lower limit of the value of k is 1.00.

On the other hand, the value of k is the sample No. 81 and 86
As shown in Fig. 1, when 1.04, a sintered body having desired electrical characteristics can be obtained. 82 and 87
As shown in (1), in the case of 1.05, a dense sintered body cannot be obtained even by firing at 1250 ° C. Therefore, the upper limit of the value of k is 1.04.

Next, the addition amount of the additive component will be described. The addition amount of the additive component is the same as the sample As shown in Nos. 25 and 31, in the case of 0.2 parts by weight with respect to 100 parts by weight of the basic component, it is possible to obtain a sintered body having desired electrical characteristics by firing at 1190 to 1200 ° C. If the addition amount of the additive component is zero, the sample No. As shown in 24 and 30, a dense sintered body cannot be obtained even by firing at 1250 ° C. Therefore, the lower limit of the additive component is 100
It is 0.2 parts by weight with respect to parts by weight of the basic component.

On the other hand, the addition amount of the additive component is the same as the sample No. Two
As shown in 8 and 34, when the amount of the basic component is 5 parts by weight with respect to 100 parts by weight, a sintered body having desired electrical characteristics can be obtained. No. As shown in Nos. 29 and 35, when 7 parts by weight is added to 100 parts by weight of the basic component, a dense sintered body cannot be obtained by firing at 1250 ° C., or the relative dielectric constant ε _s is less than 7,000. Becomes Therefore, the upper limit of the added amount of the additive component is 5 parts by weight with respect to 100 parts by weight of the basic component.

Next, a preferable composition range of the additive component will be described. The preferable composition range of the additive component is Li in FIG.
It can be determined based on a triangular diagram showing the composition ratio of ₂ O—SiO ₂ —MO.

The first point A in the triangular diagram is the sample No. L of 1
i ₂ O is 1 mol%, SiO ₂ is 80 mol%, and MO is 19
The second point B indicates the sample No. L of 2
i ₂ O is 1 mol%, SiO ₂ is 39 mol%, and MO is 60.
The third point C is the sample No. L of 3
i ₂ O is 30 mol%, SiO ₂ is 30 mol%, and MO is 4
The fourth point D is the sample No. No. 4 has a composition of 50 mol% Li ₂ O, 50 mol% SiO ₂ , and 0 mol% MO, and the fifth point E is sample No. 5 has a composition of 20 mol% Li ₂ O, 80 mol% SiO ₂ , and 0 mol% MO.

The additive component of the sample belonging to the composition range of the present invention is within a range surrounded by five straight lines connecting the first to fifth points A to E of the triangular diagram shown in FIG. 2 in this order. .. If the composition of the additive component is within this range, a sintered body having desired electrical characteristics can be obtained. On the other hand, sample N
o. When the composition of the additive component is out of the range specified in the present invention as in Nos. 11 to 16, a dense sintered body cannot be obtained by firing at 1250 ° C.

The MO component is, for example, sample No. 17
~ 21, as shown in BaO, SrO, CaO, Mg
It may be one of O and ZnO, or may have an appropriate ratio as shown in other samples.

[0080]

According to the present invention, since the composition of the dielectric porcelain composition forming the dielectric layer of the porcelain capacitor is configured as described above, the relative permittivity ε _s is 7,000 to 197.
00, which is a dramatic improvement, and therefore, there is an effect that the size and capacity of the porcelain capacitor can be reduced.

Further, according to the present invention, since the composition of the dielectric porcelain composition forming the dielectric layer of the porcelain capacitor is configured as described above, the CR product at high temperature can be increased, and therefore, This has the effect of increasing the reliability of the porcelain capacitor at high temperatures.

Furthermore, according to the present invention, since the dielectric ceramic composition forming the dielectric layer of the ceramic capacitor is sintered in a non-oxidizing atmosphere, the internal electrodes are made of an inexpensive base metal such as nickel. Since it can be formed of a conductive paste, the cost of the porcelain capacitor can be reduced in combination with the small size and large capacity of the porcelain capacitor.

[Brief description of drawings]

FIG. 1 is a sectional view of a laminated ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a triangular diagram showing a composition range of additive components of a dielectric ceramic composition forming a dielectric layer of a ceramic capacitor according to the present invention.

[Explanation of reference numerals] 12 dielectric ceramic layer 14 internal electrode 15 laminated sintered body chip 16 external electrode 18 zinc electrode layer 20 copper layer 22 Pb-Sn solder layer

[Table 3 ○ 1]

[Table 3 ○ 2]

[Table 3-3]

[Table 3-4]

[Table 3-5]

[Table 3 ○ 6]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroshi Kishi 6-16-20 Ueno, Taito-ku, Tokyo Taiyo Induction Co., Ltd.

Claims (2)

[Claims] 1. One or more dielectric porcelain layers made of a dielectric porcelain composition, and 2 sandwiching the dielectric porcelain layers.
A ceramic capacitor provided with the above internal electrodes, wherein the dielectric ceramic composition is obtained by firing a mixture of 100.0 parts by weight of a basic component and 0.2 to 5.0 parts by weight of an additive component. Where the basic component is (1-α) {(Ba _1-x Ca _x ) O} _k (Ti _1-y Zr _y ) O ₂ + α (R _1-z R ′ _Z ) O _3/2 (however, , R is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu, and R ′.
Is Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or more elements selected from Tm and Lu, α, x, y, z, k are 0.002 ≦ α ≦ 0.04 0 ≦ x ≦ 0.27 0.05 ≦ y ≦ 0 .26 0.5 ≦ z ≦ 0.9 1.00 ≦ k ≦ 1.04), and the additive components are Li ₂ O, SiO ₂ and MO (however, MO
Is one or more oxides selected from BaO, SrO, CaO, MgO and ZnO), and the composition range of the Li ₂ O, the SiO ₂ and the MO is such that the composition is mol%. In the triangular diagram shown by, the Li ₂ O is 1 mol%, the SiO ₂ is 80 mol%,
A first point A showing a composition of MO of 19 mol%, 1 mol% of Li ₂ O and 39 mol% of SiO ₂ .
A second point B showing a composition of MO of 60 mol%, and a third point C showing a composition of 30 mol% of Li ₂ O, 30 mol% of SiO _{2, and} 40 mol% of MO. A fourth point D showing a composition of 50 mol% of Li ₂ O, 50 mol% of SiO _{2, and} 0 mol% of MO, 20 mol% of Li ₂ O, and 80 mol of SiO ₂ %, The MO is in a region surrounded by five straight lines connecting the fifth point E, which indicates a composition of 0 mol%, in this order, and the ceramic capacitor. 2. A step of preparing a mixture made of unsintered porcelain powder, a step of forming an unsintered porcelain sheet made of the mixture, and at least two or more conductive paste films formed from the unsintered porcelain sheet. And a step of heat-treating the laminate in a non-oxidizing atmosphere, and a step of heat-treating the laminate subjected to the heat treatment in an oxidizing atmosphere. A mixture of porcelain powder for binding comprises 100.0 parts by weight of a basic component and 0.2 to 5 parts by weight of an additional component, and the basic component is (1-α) {(Ba _1-x Ca _x ) O} _k (Ti _1-y Zr _y ) O ₂ + α (R _1-z R ′ _Z ) O _3/2 (wherein R is selected from La, Ce, Pr, Nd, Pm, Sm and Eu) One or more elements, R '
Is Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or more elements selected from Tm and Lu, α, x, y, z, k are 0.002 ≦ α ≦ 0.04 0 ≦ x ≦ 0.27 0.05 ≦ y ≦ 0 .26 0.5 ≦ z ≦ 0.9 1.00 ≦ k ≦ 1.04), and the additive components are Li ₂ O, SiO ₂ and MO (however, MO
Is one or more oxides selected from BaO, SrO, CaO, MgO and ZnO), and the composition range of the Li ₂ O, the SiO ₂ and the MO is such that the composition is mol%. In the triangular diagram shown by, the Li ₂ O is 1 mol%, the SiO ₂ is 80 mol%,
A first point A showing a composition of MO of 19 mol%, 1 mol% of Li ₂ O and 39 mol% of SiO ₂ .
A second point B showing a composition of MO of 60 mol%, and a third point C showing a composition of 30 mol% of Li ₂ O, 30 mol% of SiO _{2, and} 40 mol% of MO. A fourth point D showing a composition of 50 mol% of Li ₂ O, 50 mol% of SiO _{2, and} 0 mol% of MO, and 20 mol% of Li ₂ O and 80 mol of SiO ₂ %, The MO is in a region surrounded by five straight lines connecting the fifth point E indicating a composition of 0 mol% in this order, and a method for manufacturing a porcelain capacitor.