JP2761690B2 - Porcelain capacitor and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic capacitor having a single-layer or multilayer structure in which one or more dielectric ceramic layers are sandwiched by internal electrodes, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a laminated ceramic capacitor is formed by printing a conductive paste mainly composed of a noble metal such as platinum or palladium in a desired pattern on an unsintered ceramic sheet (green sheet) made of a dielectric ceramic raw material powder. A plurality of such unsintered porcelain sheets are stacked and pressed, and fired at 1300 ° C. to 1600 ° C. in an oxidizing atmosphere.

Here, the reason why the conductive paste mainly containing a noble metal such as platinum or palladium is used is that the conductive paste mainly containing a noble metal such as platinum or palladium is used. The laminated ceramic capacitor is placed in an oxidizing atmosphere at 1300 ° C. to 1600 ° C.
The conductive paste does not oxidize even if it is fired at such a high temperature,
This is because a desired internal electrode can be obtained. However, since noble metals such as platinum and palladium are expensive materials, there has been a problem that the cost of the conventional laminated ceramic capacitor is high.

As a device capable of solving this problem, Japanese Patent Publication No. 60-20851 to the present applicant discloses {(Ba _x Ca _y Sr _z ) O} _k (Ti _n Zr _1-n ) O. ₂ and Li ₂ O, SiO ₂ and MO (where MO is BaO,
A dielectric porcelain composition comprising an additional component comprising one or more oxides selected from CaO and SrO) is disclosed.

Japanese Patent Application Laid-Open No. 61-147404 discloses a basic component consisting of {(Ba _1-xy Ca _{x S r y} ) O} _k (Ti _1-z Zr _z ) O ₂ and B ₂ O ₃ There is disclosed a dielectric porcelain composition comprising: and an additive component composed of SiO ₂ and Li ₂ O.

Japanese Patent Application Laid-Open No. 61-147405 discloses a basic component consisting of {(Ba _{1 -xy} Ca _{x S r y} ) O} _k (Ti ₁ -z Zr _z ) O ₂ and B ₂ O ₃ A dielectric porcelain composition comprising: and an additive component comprising SiO ₂ is disclosed.

Japanese Patent Application Laid-Open No. 61-147406 discloses a basic component comprising {(Ba _1-xy Ca _{x S r y} ) O} _K (Ti _1-z Zr _z ) O ₂ and B ₂ O ₃ And SiO ₂ and MO (where MO is Ba
A dielectric porcelain composition comprising an additional component comprising one or more oxides selected from O, CaO and SrO) is disclosed.

The dielectric porcelain compositions disclosed in these publications can be obtained by firing at a relatively low temperature of 1200 ° C. or less in a reducing atmosphere. 5000 or more, resistivity ρ is 1 × 1
0 ⁶ MΩ · cm or more.

[0009]

In recent years, there has been a remarkable progress in increasing the density of electronic circuits, and there has been an extremely strong demand for miniaturization of multilayer ceramic capacitors, and multilayer ceramic capacitors have been used for electrical equipment in automobiles and the like. Therefore, there is also a very strong demand for high-temperature reliability of the laminated ceramic capacitor.

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

Therefore, an object of the present invention is to obtain a dielectric ceramic composition comprising a dielectric layer, which is obtained by firing at a temperature of 1200 ° C. or lower in a non-oxidizing atmosphere. Dielectric constant ε of 7000 or more, dielectric loss t
an δ is 2.5% or less and resistivity ρ is 1 × 10 ⁶ MΩ · c
An object of the present invention is to provide a porcelain capacitor having a CR product at a temperature of not less than m and at 150 ° C. of not less than 1000 F · Ω and an electrical property more excellent than that of a conventional capacitor, and a method of manufacturing the same.

[0012]

According to the present invention, there is provided a ceramic capacitor comprising one or more dielectric ceramic layers made of a dielectric ceramic composition, and two or more internal electrodes sandwiching the dielectric ceramic layers. And a dielectric ceramic composition comprising: 100.0 parts by weight of a basic component;
2 to 5.0 parts by weight of a mixture with an additive component, wherein the basic component is (1-α) {(Ba _1-wx C _aw Sr _x ) O} _k (Ti _1-y Zr _y ) O ₂ + α (R _{1 -z} R ′ _Z ) O _3/2 (where R is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu; R '
Are Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or two or more elements selected from Tm and Lu, α, w, x, y, z, and k are: 0.002 ≦ α ≦ 0.040 0 ≦ w ≦ 0.27 0 <x ≦ 0 .37 0 <y <0.26 0.05 ≦ 0.6x + y ≦ 0.26 0.5 ≦ z ≦ 0.9 1.00 ≦ k ≦ 1.04), and the additive component is B ₂ O ₃ and S
iO ₂ and MO (where MO is BaO, SrO, CaO,
In a triangular diagram showing the composition range of the B ₂ O ₃ , the SiO _2, and the MO in terms of mol%, A first point A having a composition of 1 mol% of B ₂ O _3, 80 mol% of SiO _{2 and} 19 mol% of MO, 1 mol% of B ₂ O _{3 and} 39 mol of SiO ₂
Mol%, said second point B having a composition of said MO of 60 mol%.
And a third point C having a composition of 30 mol% of B ₂ O _3, 0 mol% of SiO _{2, and} 70 mol% of MO,
90 mol% of the B ₂ O _3, 0 mol% of the SiO ₂ ,
A fourth point D indicating the composition of the MO of 10 mol%, and a fifth point E indicating the composition of the B ₂ O ₃ of 90 mol%, the SiO ₂ of 10 mol%, and the MO of 0 mol%. And the B ₂
O ₃ is 20 mol%, SiO ₂ is 80 mol%, and M is
This is in a region surrounded by six straight lines connecting the sixth point F indicating the composition of 0 mol% with O in this order.

Here, (R) in the composition of the basic component
_1-z R ′ _Z ) O _3/2 ratio, that is, the value of α is 0.002 ≦ α
≦ 0.04 because the value of α is 0.002 ≦ α
In the case of ≦ 0.04, desired electrical characteristics can be obtained, but in the case of less than 0.002, ta
nδ is greatly deteriorated and resistivity ρ is 1 × 10 ³ MΩ · cm
If it exceeds 0.04, the firing temperature is 1
This is because a dense sintered body cannot be obtained even at 250 ° C.

The ratio of the number of atoms of Ca in the composition formula of the basic component, that is, the value of w is set to 0 ≦ w ≦ 0.27, when the value of w is 0 ≦ w ≦ 0.27. It is possible to obtain a sintered body having desired electrical characteristics, a flat temperature characteristic, and a high resistivity ρ, but if it exceeds 0.27, it is necessary to obtain a dense sintered body. Firing temperature is 12
As high as 50 ° C., relative dielectric constant epsilon _s is because less than 7000.

Since Ca is an element used for flattening the temperature characteristics of the ceramic capacitor and improving the resistivity ρ as described above, even if it is not intentionally contained, ie, the value of w, Even if the value is set to zero, a sintered body having desired electrical characteristics can be obtained.

The value of the relational expression 0.6x + y is set to 0.05
≦ 0.6x + y ≦ 0.26 is based on the relational expression 0.6x
When the value of + y is in this range, a sintered body having desired electrical characteristics can be obtained, but the relational expression 0.6x +
or value is less than 0.05 of y, if you or exceeds 0.26, because both the dielectric constant epsilon _s is less than 7000.

Here, the range of the value of the relational expression 0.6x + y is determined because Sr and Zr whose ratios are indicated by x and y.
Is an element that shifts the Curie point to a lower temperature side and must be considered as a whole. However,
The characteristic of Sr as a shifter is 3 when Zr is 1.
Since / 5 (= 0.6), x was corrected by multiplying by a coefficient 0.6.

The value of the relational expression 0.6x + y is 0.26.
If the value of x exceeds 0.37, the relative permittivity ε _s becomes less than 7000, even if the value is less than or equal to below. Therefore, the relational expression 0.6x
The upper limit of + y is 0.26, but at the same time the upper limit of x must be 0.37. Therefore, Sr, Z
The ratio of r is within a range satisfying 0 <x ≦ 0.37 and 0 <y <0.26, and 0.05 ≦ 0.6x + y ≦ 0.
26 must be satisfied.

Further, 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 be 0.5 ≦ z ≦ 0.9, is that the value of z is 0.5 ≦ z ≦ In the case of 0.9, a sintered body having desired electric characteristics can be obtained,
If the value is less than 0.5 or exceeds 0.9, the high temperature CR product will be less than 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, and similar results are obtained using one or a plurality of them. Also, Sc, Y, Gd, D of the R 'component
Since y, Ho, Er, Yb, Tb, Tm and Lu work almost in the same way, even if one selected from these is used,
Alternatively, similar results can be obtained by using a plurality.

In the composition formula of the basic component, {(Ba _1-wx Ca _w
Sr _x ) O}, that is, the value of k is 1.00 ≦ k ≦ 1.0
The reason for setting the value to 4 is that when the value of k is 1.00 ≦ k ≦ 1.04, a sintered body having desired electric characteristics can be obtained, but when the value of k is less than 1.00. Shows that the dielectric loss tan δ greatly deteriorates and the resistivity ρ is 1 × 10 ⁶ MΩ ·
cm, and the high-temperature CR product deteriorates significantly,
This is because, when the temperature exceeds 1,250 ° C., a dense sintered body cannot be obtained.

In the basic components, a small amount of MnO ₂ (preferably 0.05) is used as long as the object of the present invention is not impaired.
(0.1% by weight) may be added to improve the sinterability. Further, other substances may be added as needed. In addition, as a starting material for obtaining a basic component, an oxide other than those shown in Examples may be used,
A hydroxide or other compound may be used.

Next, the addition amount of the additive component is set to 0.2 to 5.0 parts by weight based on 100 parts by weight of the basic component.
When the amount of the additional component is within this range, 1190-
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 at a firing temperature of 1250 ° C. and, also, if it exceeds 5.0 parts by weight, the dielectric constant epsilon _s is from less than 7000.

In a triangular diagram showing the composition of the additive component in terms of mol% of the composition of B ₂ O ₃ , SiO ₂ and MO, the composition is within a range surrounded by six straight lines connecting points A to F 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
This is because a dense sintered body cannot be obtained by sintering 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 for manufacturing a ceramic capacitor according to the present invention comprises the steps of: preparing a mixture of unsintered porcelain powder comprising the aforementioned basic components and additive components; A step of forming a sheet, a step of forming a laminate in which the unsintered porcelain sheet is sandwiched by at least two or more conductive paste films, and a step of heat-treating the laminate in a non-oxidizing atmosphere; 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 air atmosphere, but may be an atmosphere having a low oxygen concentration, such as a mixture of N ₂ and several ppm of O _2, and an atmosphere having an arbitrary oxygen concentration. Can be. What kind of temperature or what kind of oxygen concentration the atmosphere should be changed in various ways in consideration of oxidation of the electrode material (nickel or the like) and oxidation of the dielectric ceramic layer. In the embodiment described later, the temperature of this heat treatment was set to 600 ° C., but the temperature is not limited to this temperature.

In the embodiments described later, the heat treatment in the non-oxidizing atmosphere and the heat treatment in the oxidizing atmosphere are performed in one continuous firing profile. Alternatively, the heat treatment step in an oxidizing atmosphere can be performed separately from the heat treatment step.

In the embodiment, a Zn electrode is used as an external electrode. However, it is a matter of course that an electrode of Ni, Ag, Cu or the like can be used by selecting the baking conditions of the electrode. An external electrode may be applied to the end face of the unfired laminate to fire the laminate and bake the external electrodes at the same time.

The present invention can of course be applied to general single-layer ceramic capacitors other than the multilayer ceramic capacitor.

[0031]

EXAMPLE First, the sample Nos. The case of 1 will be described. Preparation of Basic Components The compounds shown in Table 1 were weighed, and these compounds were put into a pot mill together with a plurality of alumina balls and 2.5 liters of water, followed by stirring and mixing for 15 hours to obtain a mixture.

[0032]

[Table 1]

Here, the weight (g) of each compound in Table 1 is
Composition formula of the basic component (1-α) {(Ba 1-wx Ca w Sr x) O} k (Ti 1-y Zr y) O 2 + α (R 1-z R 'Z) O 3/2 ( provided that , R is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu;
Are Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
Tm and one or more elements selected from Lu) ......... (1) in the first term _{{(Ba 1-wx Ca w} Sr x) O} k (Ti 1-y Zr y) O ₂ is
{(Ba _0.85 Ca _0.07 Sr _0.08 ) O} _1.01 (Ti _0.90 Zr _0.10 ) O ₂ It is a value calculated and calculated to be ₂ .

Next, the raw material mixture was placed in a stainless steel pot, dried at 150 ° C. for 4 hours using a hot-air drier, and the dried mixture was roughly pulverized. About 1200 ° C in air
For 2 hours to obtain the component powder of the first item in the composition formula (1) of the above basic component (first basic component).

The sample Nos. As shown in FIG. 1, 98 mol parts (984.16 g) of the powder of the first basic component and 2 mol parts (15 mol%) were used so that 1-α was 0.98 mol% and α was 0.02 mol%. .84 g, of which Dy ₂ O
₃ is 11.49 g and Pr ₂ O ₃ is 4.35 g) (the second term component in the formula (1)).
Was mixed in a wet pot mill and dried at 150 ° C. to obtain 1000 g of a basic component.

Preparation of Additives Further , 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 wt.
The mixture was added together with 0 ml of alcohol and mixed by stirring for 10 hours to obtain a mixture.

[0037]

[Table 2]

Here, the weight (g) of each compound in Table 2 is
B ₂ O ₃ 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 calculated and calculated so as to have a composition of MgO (5.7 mol%)｝. Moreover, among MO, BaO, CaO and M
The proportion of gO is as follows: BaO is 20 mol%, CaO is 5 mol%.
0 mol% and MgO are 30 mol%.

Next, the mixture is exposed to the atmosphere for about 10 hours.
The mixture was calcined at a temperature of 00 ° C. for 2 hours, put 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 having the above composition. A powder was obtained.

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

Formation of Unsintered Porcelain Sheet Next, the above-mentioned slurry was put into a vacuum defoaming machine and defoamed.
The defoamed slurry is applied on a polyester film to a predetermined thickness using a reverse coater.
It was dried by heating at 00 ° C. to obtain a long non-sintered 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 and 0.9 g of ethyl cellulose were added to 9.1 g of butyl carbitol.
Into a stirrer and stirred for 10 hours,
A conductive paste for an internal electrode was obtained.

Then, 50 patterns (length: 14 mm, width: 7 mm) of this conductive paste were formed on one surface of the unsintered porcelain 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 upward. During 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, the unsintered porcelain sheet having a thickness of 60 μm was further laminated on each of the upper and lower surfaces of the laminate as described above, thereby obtaining a laminate.

Crimping and cutting of the laminate Next, at a temperature of about 50 ° C., a load of about 40 tons is applied to the laminate from the thickness direction, so that the unsintered porcelain sheet constituting the laminate is formed. The two were pressed together. Then, this laminate was cut into a lattice to obtain 50 laminate chips.

The firing of the laminate chip then placed the laminate chip furnace capable atmosphere firing, the furnace to the atmosphere, warmed to 600 ° C. at a rate of 100 ° C. / h, green The organic binder in the porcelain sheet was burned off.

Thereafter, the atmosphere in the furnace was changed from an air atmosphere to a reducing atmosphere {H ₂ (2% by volume) + N ₂ (98% by volume)}, and the temperature in the furnace was changed from 600 ° C. to 1140 ° C. by 100 ° C.
The temperature was raised at a rate of 1 ° C./h, the temperature of 1140 ° C. was maintained for 3 hours, then the temperature was lowered at a rate of 100 ° C./h, and the atmosphere in the furnace was changed to an atmospheric atmosphere (oxidizing atmosphere).
Temperature was maintained for 30 minutes to perform an oxidation treatment, and then cooled to room temperature to obtain a laminated sintered body chip.

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

Here, the external electrode 16 is coated with a conductive paste composed of zinc, glass frit and vehicle on the side surface, and after drying the conductive paste, it is dried in air at 550. Baked at a temperature of 15 ° C. for 15 minutes to form a zinc electrode layer 18.
8, a copper layer 20 was formed by an electroless plating method, and a Pb-Sn solder layer 22 was formed on the copper layer 20 by an electroplating method.

The thickness of the dielectric ceramic layer 12 of the laminated ceramic capacitor 10 is 0.02 mm, and the thickness of 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 Electric Characteristics Next, the electric characteristics of the laminated ceramic capacitor 10 were measured.
When the average value was obtained, as shown in the right column of Table 3, the relative dielectric constant ε _s was 16050, tan δ was 1.1%,
The resistivity ρ was 3.71 × 10 ⁶ MΩ · cm, and the high-temperature CR product was 1750 F · Ω.

The electrical characteristics were measured in the following manner. (A) The relative permittivity ε _s is obtained 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. (25
mm ² ) and the thickness (0.02 mm) of the dielectric ceramic layer 12 between the pair of internal electrodes 14, 14. (B) The dielectric loss tan δ (%) was measured under the same conditions as in the measurement of the relative dielectric constant ε _s described above. (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 6 and 16 was measured and calculated based on the measured value and the dimensions. (D) High temperature CR product (F · Ω) is temperature 150 ℃, frequency 1
The capacitance was measured under the conditions of kHz and a voltage (effective value) of 1.0 V. After applying DC 100 V for one 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. 1 was described, but the sample No. For 2 to 94, the compositions of the basic components and the additional components were changed as shown in the left column of Tables 3 to 3, and the firing temperature in the reducing atmosphere was changed as shown in the right column of Tables 3 to 3. Others are sample Nos. A laminated ceramic capacitor was prepared in exactly the same manner as in Example 1, and the electrical characteristics were measured in the same manner. Sample No. Table 3 shows the electrical characteristics of 2-90.
~ As shown in the right column of Table 3.

In Tables 3 to 3, in the column of 1-α, {(Ba _1-wx Ca _w
Sr _x) O} ratio of _{k (Ti 1-y Zr y} ) O 2 is the ratio of the number of atoms of Ba in the 1-w-x column first term of formula basic components in the are column w Is the Ca in the first term of the composition formula of the basic component
In the column of x, the ratio of the number of atoms of
In the column of 1-y, the ratio of the number of atoms of Sr in the term is the ratio of the number of atoms of Ti in the first term of the composition formula of the basic component.
In the column of y, the ratio of the number of atoms of Zr in the first term of the composition formula of the basic component is shown, and in the column of k, {(Ba _1-wx C _aw Sr _x ) O in the first term of the composition formula of the basic component is shown. proportion of} is, column fraction in the second term of the formula of the basic component of the _{(R 1-z R 'Z} ) O 3/2 for the α is,
The 1-z column shows the proportion of the number of R atoms in the second term of the basic component composition formula, and the z column shows the proportion of the R 'atom in the second term of the basic component composition formula. ing.

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 indicates the weight of the added component with respect to 100 parts by weight of the basic component, and the column of the composition indicates B by weight.
The proportions of ₂ O ₃ , SiO ₂ and MO are shown in mol%,
In the column of O content, the proportions of BaO, SrO, CaO, MgO and ZnO are shown in mol%.

The sample No. Sample Nos. 1 to 19 clarify the appropriate range of glass as an additive component. 20-3
1 clarifies the appropriate range of the addition amount of the additive component, and
o. Sample Nos. 32 to 43 clarify the appropriate range of w which is the ratio of the number of Ca atoms. Sample Nos. 44 to 59 clarify the appropriate range of the x value which is the ratio of the number of atoms of Sr and the appropriate range of the y value which is the ratio of the number of atoms of Zr, that is, the appropriate range of 0.6x + y. Sample Nos. 60 to 69 clarify the appropriate range of z which is the ratio of the number of atoms of R ′. 70
80 clarify the appropriate range of α, which is the ratio of (R _{1 -z} R ′ _Z ) O _3/2 , 81 to 90 are {(Ba _1-wx C _aw Sr _x ) O}
This clarifies the appropriate range of k, which is the ratio of

[0057]

[Table 3]

[0058]

[Table 3]

[0059]

[Table 3]

[0060]

[Table 3]

[0061]

[Table 3]

[0062]

[Table 3]

As is clear from Tables 3 to 3, according to the sample according to the present invention, 12
By firing at 00 ° C. or less, the relative dielectric constant ε _s is 7000 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 electric characteristics of F · Ω or more.

On the other hand, no. 11-13, 20, 2
5,26,31,37,43,44,49,57,5
9,60,69,70,75,76,80,81,8
According to the samples of 5, 86 and 90, it is not possible to obtain a porcelain capacitor having desired electrical characteristics. Therefore,
These Nos. Are out of the scope of the present invention.

Next, the reasons for limiting the composition range of the dielectric ceramic composition used in the ceramic capacitor according to the present invention will be described with reference to Sample Nos. This will be described with reference to FIGS.

First, the ratio of the number of Ca atoms in the composition formula of the basic component, that is, the value of w will be described. w is the value of Sample No. 0.27, as shown in 36 and 42
In the case of No. 5, a sintered body having desired electrical characteristics can be obtained. As shown in 37 and 43,
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 7000. Therefore, the upper limit of the value of w is 0.27.

The sample No. 33-36, 39-42
As shown in FIG. 5, Ca has an effect of flattening the temperature characteristics and an effect of improving the resistivity ρ.
o. As shown in 32 and 38, a sintered body having desired electrical characteristics can be obtained even if it is zero. Therefore, the lower limit of the value of w is zero.

Next, the value of x, which is the ratio of the number of atoms of Sr, and the value of y, which is the ratio of the number of atoms of Zr, in the composition formula of the basic component are represented by the value of the relational expression 0.6x + y. Will be described. The value of the relational expression 0.6x + y indicates that the sample N
o. As shown in FIG. 50, in the case of 0.05, a sintered body having desired electrical characteristics can be obtained.
o. As shown in 44, in the case of 0.035, the relative dielectric constant epsilon _s is less than 7000. Therefore, the relational expression 0.6x
The lower limit of + y is 0.05.

On the other hand, the value of the relational expression 0.6x + y
o. As shown in FIGS.
In the case of No. 5, a sintered body having desired electrical characteristics can be obtained. As shown in FIGS.
If it becomes 0.290,0.285 beyond 26, the dielectric constant epsilon _s is less than 7000. Therefore, the upper limit of the relational expression 0.6x + y is 0.26.

However, the value of the relational expression 0.6x + y is 0.26
Sample No. As shown in 49, when the value of x exceeds 0.37 and becomes 0.40, the relative dielectric constant 率_s becomes less than 7000. Therefore, the relational expression 0.6x +
The upper limit of y is 0.26, but at the same time the upper limit of x must be 0.37.

Note that Sr and Zr represented by x and y have the same effect of shifting the Curie point to a lower temperature and increasing the relative dielectric constant at room temperature, where 0 <x ≦ 0.37 and 0
<Y <0.26 and 0.05 ≦
It can be used in a range that satisfies 0.6x + y ≦ 0.26.

Next, the ratio of (R _{1 -z} R ' _z ) in the second term of the composition formula of the basic component, that is, the value of α will be described. The value of sample No. As shown in Nos. 71 and 77, a sintered body having the desired electrical characteristics can be obtained in the case of 0.002. As shown in 70 and 76, in the case of 0.001, the dielectric loss tan
δ greatly deteriorates, and the resistivity ρ becomes less than 1 × 10 ³ MΩ · cm. Therefore, the lower limit of the value of α is 0.002.

On the other hand, when the value of α 74 and 79
As shown in the figure, when the ratio is 0.04, a sintered body having desired electric characteristics can be obtained. As shown in 75 and 80, 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.

The R components La, Ce, Pr, Nd,
Pm and Eu work in much the same way, and similar results are obtained using one or a plurality of them.

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 sample no. In the case of 0.5 as shown in FIG. 61, a sintered body having desired electrical characteristics can be obtained. As shown by 60, in the case of 0.4, the high-temperature CR product is less than 1000 F · Ω. Therefore, the lower limit of z is 0.5.

On the other hand, when the value of z is As shown in FIG. 68, in the case of 0.9, a sintered body having desired electric characteristics can be obtained. As shown at 69, in the case of 0.95, the high temperature CR product becomes less than 1000 F · Ω. Therefore, the upper limit of the value of z is 0.9.

Note that the R 'components Sc, Y, Dy, Ho,
Er and Yb work in much the same way, and similar results can be obtained using one or a plurality of them.

Next, in the composition formula of the basic component, {(Ba
_1-wx Ca _w Sr _x ) O}, that is, the value of k will be described. The value of sample no. As shown at 82 and 87,
In the case of 1.00, a sintered body having desired electrical characteristics can be obtained. As shown in 81 and 86, in the case of 0.99, tan δ becomes 2.5% or more, the resistivity ρ becomes less than 1 × 10 ⁴ MΩ · cm,
The high temperature CR product deteriorates significantly. Therefore, the lower limit of the value of k is 1.00.

On the other hand, when the value of k is the sample No. 84 and 89
As shown in the figure, a sintered body having desired electrical characteristics can be obtained when the ratio is 1.04. 85 and 90
As shown in the figure, 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 amount of the additional component will be described. When the amount of the added component is the As shown in 21 and 27, in the case of 0.2 parts by weight with respect to 100 parts by weight of the basic component, a sintered body having desired electric characteristics can be obtained by firing at 1190 to 1200 ° C. When the addition amount of the additive component is zero, the sample No. As shown in 20 and 26, a dense sintered body cannot be obtained even by firing at 1250 ° C. Therefore, the lower limit of the added component is 100
0.2 parts by weight based on parts by weight of the basic component.

On the other hand, the amount of the additive component 2
As shown in 4 and 30, when 5 parts by weight with respect to 100 parts by weight of the basic component, a sintered body having desired electric characteristics can be obtained, but the amount of the additional component is less than that of the sample. No. As shown in FIGS. 25 and 31, in the case of 7 parts by weight with respect to 100 parts by weight of the basic component, the relative dielectric constant ε _s is 70%.
It becomes less than 00. Therefore, the upper limit of the amount of the added component is 5 parts by weight based on 100 parts by weight of the basic component.

Next, a preferable composition range of the additional component will be described. A preferred composition range of additive component, in FIG. 2 B ₂
It can be determined based on a triangular diagram showing the composition ratio of O ₃ —SiO ₂ —MO.

The first point A in the triangular diagram corresponds to the sample No. 1 B
1 mol% of ₂ O _3, 80 mol% of SiO ₂ ,
Mol%, and the second point B is the sample No. 2 B
1 mol% of ₂ O _3, 39 mol% of SiO ₂ , MO of 60
%, And the third point C is the sample No. 3 B
₂ O ₃ is 30 mol%, SiO ₂ is 0 mol%, MO is 70 mol%.
%, And the fourth point D is the sample No. 4 B
90 mol% of ₂ O _3, 0 mol% of SiO ₂ , MO of 10
Mol%, the fifth point E indicates the sample No. 5 B
90 mol% of ₂ O _3, 10 mol% of SiO _{2 and} 0 mol of MO
The sixth point F indicates the composition of Sample No. 6 of B
20 mol% of ₂ O _3, 80 mol% of SiO ₂ , MO of 0%
It shows the composition in mole%.

The additional components of the sample belonging to the composition range of the present invention are within the range surrounded by six straight lines connecting the first to sixth points A to F in the triangular diagram shown in FIG. . When the composition of the additive component is within this range, a sintered body having desired electric characteristics can be obtained. On the other hand, sample N
o. If the composition of the additional component is outside the range specified in the present invention as in 11 to 13, a dense sintered body cannot be obtained by firing at 1250 ° C.

The MO component is, for example, the sample No. 14
-18, BaO, SrO, CaO, Mg
Any one of O and ZnO may be used, or an appropriate ratio may be used as shown in other samples.

[0086]

According to the present invention, since the composition of the dielectric ceramic composition constituting the dielectric layer of the ceramic capacitor is configured as described above, the relative dielectric constant ε _s is 7000 to 218.
00, which is advantageous in that the porcelain capacitor can be reduced in size and capacity.

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

Further, according to the present invention, the dielectric ceramic composition constituting the dielectric layer of the ceramic capacitor is sintered in a non-oxidizing atmosphere, so that the internal electrodes are made of an inexpensive base metal such as nickel. The ceramic capacitor can be formed of a conductive paste. Therefore, there is an effect that the cost of the ceramic capacitor can be reduced in combination with the increase in the size and the capacity of the ceramic capacitor.

[Brief description of the drawings]

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

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

[Explanation of symbols]

 Reference Signs List 12 dielectric ceramic layer 14 internal electrode 15 laminated sintered 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]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C04B 35/46 H01B 3/12 326 35/49 335 H01B 3/12 326 C04B 35/46 C 335 35/49 Z (72) Invention Hiroshi Kishi Taiyou Yuden 6-16-20 Ueno Taito-ku, Tokyo Taiyo Yuden Co., Ltd. (58) Field surveyed (Int. Cl. ⁶ , DB name) H01G 4/12

Claims (2)

(57) [Claims] At least one dielectric porcelain layer made of a dielectric porcelain composition, and a dielectric porcelain sandwiching the dielectric porcelain layer.
In the above porcelain capacitor provided with the internal electrodes, the dielectric porcelain 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 additional component. Wherein the basic component is (1-α) {(Ba _1-wx C _aw Sr _x ) O} _k (Ti _1-y Zr _y ) O ₂ + α (R _1-z R ′ _Z ) O _3/2 (Where R is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu, R ′
Are Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or more elements selected from Tm and Lu, α, w, x, y, z, and k are: 0.002 ≦ α ≦ 0.040 0 ≦ w ≦ 0.27 0 <x ≦ 0 0.30 <y <0.26 0.05 ≦ 0.6x + y ≦ 0.26 0.5 ≦ z ≦ 0.9 1.00 ≦ k ≦ 1.04). B ₂ O ₃ , SiO ₂ and MO (however, MO
Is one or more oxides selected from BaO, SrO, CaO, MgO, and ZnO), and the composition range of B ₂ O ₃ , SiO _2, and MO is such that % In the triangular diagram, the B ₂ O ₃ is 1 mol%, the SiO ₂ is 80 mol%,
A first point A where the MO has a composition of 19 mol%, the B ₂ O ₃ is 1 mol%, the SiO ₂ is 39 mol%,
A second point B indicating a composition in which the MO is 60 mol%, the B ₂ O ₃ is 30 mol%, the SiO ₂ is 0 mol%,
A third point C indicating a composition in which the MO is 70 mol%, the B ₂ O ₃ is 90 mol%, the SiO ₂ is 0 mol%,
A fourth point D indicating the composition of the MO of 10 mol%, and a fifth point E indicating the composition of the B ₂ O ₃ of 90 mol%, the SiO ₂ of 10 mol%, and the MO of 0 mol%. A region surrounded by six straight lines connecting in this order a sixth point F indicating a composition of 20 mol% of B ₂ O _3, 80 mol% of SiO _{2 and} 0 mol% of MO. A porcelain capacitor, characterized in that: 2. A step of preparing a mixture comprising unsintered porcelain powder; a step of forming a non-sintered porcelain sheet comprising the mixture; and forming the unsintered porcelain sheet into at least two or more conductive paste films. Forming a laminate sandwiched by the steps of: heat-treating the laminate in a non-oxidizing atmosphere; and heat-treating the heat-treated laminate in an oxidizing atmosphere. The mixture comprising the sintered porcelain powder comprises 100.0 parts by weight of a basic component and 0.2 to 5 parts by weight of an additional component, wherein the basic component is represented by (1-α) {(Ba _1-wx Ca _{w Sr x) O} k (} Ti 1-y Zr y) O 2 + α (R 1-z R 'Z) O 3/2 ( Here, R is, La, Ce, Pr, Nd , Pm, Sm and Eu One or more elements selected from
Are Sc, Y, Gd, Dy, Ho, Er, Yb, Tb,
One or more elements selected from Tm and Lu, α, w, x, y, z, and k are: 0.002 ≦ α ≦ 0.040 0 ≦ w ≦ 0.27 0 <x ≦ 0 .37 0 <y <0.26 0.05 ≦ 0.6x + y ≦ 0.26 0.5 ≦ z ≦ 0.9 1.00 ≦ k ≦ 1.04). B ₂ O ₃ , SiO ₂ and MO (however, MO
Is one or more oxides selected from BaO, SrO, CaO, MgO, and ZnO), and the composition range of B ₂ O ₃ , SiO _2, and MO is such that % In the triangular diagram, the B ₂ O ₃ is 1 mol%, the SiO ₂ is 80 mol%,
A first point A where the MO has a composition of 19 mol%, the B ₂ O ₃ is 1 mol%, the SiO ₂ is 39 mol%,
A second point B indicating a composition in which the MO is 60 mol%, the B ₂ O ₃ is 30 mol%, the SiO ₂ is 0 mol%,
A third point C indicating a composition in which the MO is 70 mol%, the B ₂ O ₃ is 90 mol%, the SiO ₂ is 0 mol%,
A fourth point D indicating the composition of the MO of 10 mol%, and a fifth point E indicating the composition of the B ₂ O ₃ of 90 mol%, the SiO ₂ of 10 mol%, and the MO of 0 mol%. A region surrounded by six straight lines connecting in this order a sixth point F indicating a composition of 20 mol% of B ₂ O _3, 80 mol% of SiO _{2 and} 0 mol% of MO. A method for manufacturing a porcelain capacitor, the method comprising: