JPH05282918A - Ceramic capacitor and its manufacture - Google Patents

Abstract

PURPOSE:To provide a ceramic capacitor of large CR product under a high temperature by forming at least one dielectric ceramic layer into a single layered structure sandwiched between at least two internal electrodes or a multilayered structure. CONSTITUTION:A dielectric ceramic layer 12 is formed out of a mixture of a basic component (formula I) of 100 pts.wt. and additive components of 0.2-5.0 pts.wt. through baking. For the conductive paste of internal electrodes 14, nickel powder and ethyl cellulose are melted in a butyl carbitol, and are stirred, and then a pattern is printed on one side of the ceramic layer and dried. A green is layered thereon and is pressurized, press-bonded, and is cut into lattice, and a multilayered chip is thus provided. The chip is then baked and oxidation treated with, and is cooled, and a baked chip 15 is thus provided. A conductive paste consisting of zinc, glass frit and a vehicle, is applied to the side surface of the chip 15 where electrodes are exposed, and is dried, baked, and zinc electrodes 18 are provided, on which copper is plated, while Pb-Sn soldered layers 22 are provided, and external electrodes 16 are thus formed.

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 laminated structure in which one or more dielectric ceramic layers are sandwiched by at least two internal electrodes, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, laminated ceramic capacitors have been manufactured by the following method. That is, a ceramic green sheet is prepared by a doctor blade method or the like, a paste of a metal powder to be an internal electrode is printed on the green sheet, a plurality of these are stacked and thermocompression-bonded, and the temperature of 1300 ° C. or higher in the atmosphere In order to make a sintered body, the external electrode electrically connected to the internal electrode was baked on the end surface of the sintered body.

Here, as the material of the internal electrodes, if a noble metal such as palladium, platinum or silver-palladium is used,
Such precious metals have been used in many laminated porcelain capacitors up to now because they do not oxidize or directly react with the ceramic even under the above manufacturing conditions. However, the noble metal as described above has excellent characteristics as a material for the internal electrode, but on the other hand, it is expensive and has been a major cause of high cost. Therefore, as a means for solving such a problem, it has been attempted to use a base metal such as nickel as a material for the internal electrodes.

However, if nickel, for example, is used as the material of the internal electrodes, the nickel is oxidized by firing in the air atmosphere, and the oxidized nickel easily reacts with the ceramics, making it impossible to form the internal electrodes. .. In order to prevent such oxidation of the base metal, it is necessary to perform firing in a reducing atmosphere. However, if firing is performed in a reducing atmosphere, the ceramic is generally remarkably reduced and does not function as a capacitor.

Therefore, in order to solve such a problem,
The following dielectric ceramic composition is disclosed as a proposal by the applicant. For example, Japanese Patent Laid-Open No. 3-278423
The JP, (1-α) {( Ba k- (x + z) M x L z) O
_k (Ti _1-y R _y ) O _{2-y / 2} + αBaZrO ₃ (however,
M is Mg and / or Zn, L is Ca and / or S
r and R are basic components consisting of one or more metal elements selected from Sc, Y, Gd, Dy, Ho, Er and Yb, and Li ₂ O, SiO ₂ and MO (however, MO
Discloses a dielectric ceramic composition containing an additive component composed of one or more metal oxides selected from BaO, CaO and SrO.

These disclosed dielectric ceramic compositions can be used to obtain a ceramic capacitor by firing at 1200 ° C. or lower in a non-oxidizing atmosphere, and the relative dielectric constant thereof is 30.
00 or more, dielectric loss tan δ is 2.5% or less, resistivity ρ
Is 1 × 10 ⁶ MΩ · cm or more, and the temperature change rate of relative permittivity is −55% to + 15% at −55 ° C. to 125 ° C.
(Referenced to 25 ° C), -25% to 85 ° C, -10% +10
% (Based on 20 ° C.).

[0007]

In recent years, with the miniaturization and high density of electronic circuits, there has been a strong demand for small and large-capacity ceramic capacitors. As one of the methods, a laminated ceramic capacitor is known, and it has been attempted to increase the capacity by thinning the dielectric green sheet or increasing the number of laminated layers. However, in the laminated ceramic capacitor, thinning the dielectric ceramic layer causes a reduction in insulation resistance, and in particular, the CR product at a high temperature is significantly reduced.

An object of the present invention is to provide a porcelain capacitor provided with a dielectric porcelain composition having a larger CR product at high temperature than the dielectric porcelain compositions disclosed in the above publications. Specifically, although it is obtained by firing at 1200 ° C. or lower in a non-oxidizing atmosphere, the relative dielectric constant ε _{s of the} dielectric ceramic composition constituting the dielectric layer is 3300 or more, Dielectric loss tan δ is 2.5% or less, resistivity ρ is 4 × 10 ⁶ MΩ · cm or more,
CR product at 150 ° C is 200 F · Ω or more, and temperature change rate of capacitance ΔC _-55 , ΔC ₁₂₅ is -15% to +15.
%, ΔC _-25 , ΔC ₈₅ are -10% to + 10%, and a ceramic capacitor having more excellent electrical characteristics than the conventional one and a method for manufacturing the same are provided.

[0009]

The dielectric porcelain composition according to the present invention comprises 100.0 parts by weight of a basic component and 0.2 to 10 parts by weight.
5.0 parts by weight of the additive component, and the basic component is (1-α-β) (Ba _{k- (x + y)} M _x Ly _y ) O _k TiO ₂ + αBaZrO ₃ + β (R _1-z R ′ _Z ) O _3/2 (wherein M is Mg and / or Zn, L is Ca and / or Sr, R is one or two selected from La, Ce, Pr, Nd, Pm, Sm and Eu. More than one element, R '
Is Sc, Y, Gd, Tb, Dy, Ho, Er, Tm,
One or more elements selected from Yb and Lu, α, β, k, x, y, z are 0.005 ≦ α ≦ 0.04 0.002 ≦ α ≦ 0.04 1.00 ≦ k ≦ 1.050 0 ≦ x <0.10 0 ≦ y ≦ 0.05 0.01 ≦ x + y ≦ 0.10 0.5 ≦ z ≦ 0.9) , The additive component is Li ₂ O, SiO ₂ and MO (where MO is BaO,
SrO, CaO, MgO and ZnO), and the composition range of the Li ₂ O, the SiO ₂ and the MO indicates these compositions in mol%. In the diagram, the Li ₂ O content is 1 mol%, the SiO ₂ content is 80 mol%, and the MO content is 19 mol%.
The first point A indicating the composition of 1% by mole of Li ₂ O,
The second point B indicating a composition of 39 mol% of SiO _{2 and} 60 mol% of MO, and a composition of 30 mol% of Li ₂ O, 30 mol% of SiO ₂ , and 40 mol% of MO. And 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. %, Said Si
It is in a region surrounded by five straight lines connecting the fifth point E indicating the composition of O ₂ of 80 mol% and MO of 0 mol% in this order.

Here, the range of the value of α is 0.005 ≦ α
≦ 0.04 means that when the value of α is in this range, a dielectric ceramic composition having desired electrical characteristics can be obtained, but when the value of α is less than 0.005, When the temperature change rate of capacitance ΔC ₋₅₅ deviates from −15% to + 15% and ΔC ₋₂₅ deviates from −10% to + 10%, and when α exceeds 0.04, This is because the temperature change rate ΔC _{85 of the} capacity deviates from −10% to + 10%.

The range of the value of β is 0.002 ≦ β ≦
0.04 is because when the value of β is in this range,
A dielectric ceramic composition having desired electrical characteristics can be obtained, but when the value of β is less than 0.002, the resistivity ρ becomes smaller than 4.0 × 10 ⁶ MΩ · cm,
CR product at ℃ becomes less than 200F · Ω,
Further, if the value of β exceeds 0.04, a dense sintered body cannot be obtained even by firing at 1250 ° C.

Further, the range of the value of k is 1.00≤k≤
1.05 is because when the value of k is in this range,
A dielectric ceramic composition having desired electrical characteristics can be obtained, but when the value of k is less than 1.00, the resistivity ρ
Becomes less than 4.00 × 10 ⁶ MΩ · cm, and the temperature change rate of capacitance ΔC ₋₅₅ , ΔC ₁₂₅ is −15% to +15.
%, ΔC _-25 , ΔC ₈₅ deviates from −10% to + 10%, the CR product at 150 ° C. becomes 200 F · Ω or less, and when the value of k exceeds 1.05,
This is because a dense sintered body cannot be obtained even by firing at 1250 ° C.

Further, the range of the value of x + y is 0.01 ≦ x
+ Y ≦ 0.10 means that when the value of x + y is within this range, a dielectric ceramic composition having desired electrical characteristics can be obtained, but when the value of x + y becomes less than 0.01. , Capacitance temperature change rate ΔC _-55 is -15% to +1
This is because if the value of x + y deviates from 5% and the value of x + y exceeds 0.10, the temperature change rate ΔC _{85 of the} capacitance deviates from −10% to + 10%.

However, even if x + y ≦ 0.10, y
≦ 0.05 is preferable. This is because the rate of change in capacitance ΔC ₈₅ deviates from −10% to + 10% when the value of y exceeds 0.05 even if x + y ≦ 0.10 is satisfied.

The M components Mg and Zn and Ca and Sr
Works almost the same as above, one or both of Mg and Zn are used in the range satisfying 0 ≦ x ≦ 0.10, and Ca and Sr are selected in the range satisfying 0 ≦ y ≦ 0.05. Either or both can be used.

Further, the range of the value of z is 0.5 ≦ z ≦ 0.
The reason for setting 9 is that when the value of z is in this range, a dielectric ceramic composition having desired electrical characteristics can be obtained, but when the value of z is less than 0.5, the temperature at 150 ° C. CR product is less than 200 F · Ω and tan δ is 2.5%
, The resistivity ρ becomes smaller than 4.0 × 10 ⁶ MΩ · cm, and the capacitance temperature change rates ΔC ₋₅₅ and ΔC ₁₂₅ −
Deviates from 15% to + 15%, ΔC _-25 , ΔC ₈₅ is -10
If the value of z exceeds 0.9 and the value of z exceeds 0.9, it becomes 1
This is because the CR product at 50 ° C. becomes 200 F · Ω or less and the relative dielectric constant becomes 3300 or less.

The R components La, Ce, Pr, Nd,
Pm, Sm and Eu work almost in the same way, and the same result can be obtained by using one selected from these or a combination of a plurality of them. Moreover, Sc, Y, Gd, Tb, Dy, Ho, Er, Tm of R'component,
Yb and Lu work almost in the same manner, and similar results can be obtained by using one selected from these or a combination of a plurality of them.

However, the value of z is preferably 0.5≤z≤0.9 in the case where each of the R component and the R'component is one kind or plural kinds. Further, the R component and the R ′ component contribute to the improvement of the CR product at a high temperature when they are combined in a range of z value of 0.5 ≦ z ≦ 0.9. That is, by adding both the R component and the R ′ component, the CR product at 150 ° C. is 200
It becomes possible to make it more than F · Ω. In the composition formula showing the basic components, k, x, y, and z are of course the number of atoms of each element.

In the basic component, a trace amount of MnO ₂ (preferably 0.05 to
0.1% by weight) may be added to improve sinterability, or other substances may be added as necessary. Further, starting materials for obtaining the basic components may be oxides or hydroxides such as BaO, SrO, CaO or other compounds other than those shown in the examples.

Next, the range of addition amount of the additive component is set to 100.
The content of 0.2 to 5.0 parts by weight with respect to the basic components of parts by weight means that a dielectric ceramic composition having desired electrical characteristics is obtained when the amount of the added component is in this range. However, if the added amount of the additive component is less than 0.2 parts by weight, a dense sintered body cannot be obtained even by firing at 1250 ° C., and the added amount of the additive component is 5.0 parts by weight. If it exceeds, the relative permittivity ε _s will be less than 3300, and the temperature change rate ΔC _{−55 of the} capacitance will deviate from −15% to + 15%.

The composition of the additive component is Li ₂ O--SiO _2-
The first to fifth points A to A of the triangular diagram showing the composition ratio of MO in mol%.
The area surrounded by the five straight lines connecting E in order is
If the composition of the additive component is within this range, a dielectric ceramic composition having desired electrical characteristics can be obtained. However, if the composition of the additive component is outside this range, it will be dense even if fired at 1250 ° C. This is because a sintered body cannot be obtained. The MO component is BaO, SrO, CaO, MgO, Z
It may be any one of nO, or may have an appropriate ratio. In addition, the starting material of the additive component is an oxide,
Other compounds such as hydroxide may be used.

Next, in the method for manufacturing a porcelain capacitor according to the present invention, a step of preparing a mixture of unsintered porcelain powder consisting of the basic component and the additive component, and an unsintered porcelain sheet formed of the mixture. Forming a laminated body in which the green ceramic sheet is sandwiched by at least two or more conductive paste films; firing the laminated body in a non-oxidizing atmosphere; And a step of heat-treating the received 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. Further, the firing temperature in the non-oxidizing atmosphere can be variously changed in consideration of the electrode material, and when nickel is used as the internal electrode, it is 1050.
In the range of up to 1200 ° C, the heat treatment can be performed with almost no agglomeration of nickel particles.

The heat treatment temperature in the oxidizing atmosphere may be lower than the firing temperature in the non-oxidizing atmosphere, and is preferably in the range of 500 ° C 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 N ₂ mixed with several ppm of O ₂ , or an atmosphere having an arbitrary oxygen concentration can be used. The electrode material (nickel, etc.) determines the temperature and the oxygen concentration in the atmosphere.
Therefore, it is necessary to make various changes in consideration of the oxidation of the above and the oxidation of the dielectric ceramic layer. In the examples described later, this heat treatment temperature is 60
Although the temperature is 0 ° C., it 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. Of course, the firing process in the non-oxidizing atmosphere is performed. It is also possible to separately perform the heat treatment step in the oxidizing atmosphere and the independent step.

Further, in the embodiment, the Zn electrode is used as the external electrode, but Ni, Ag, Cu or the like electrodes can be used by selecting the electrode baking conditions, and the Ni external electrode is not used. It is also possible to apply the coating to the end face of the fired laminate to fire the laminate and to bake the external electrodes at the same time. The present invention is naturally applicable to general single-layer porcelain capacitors other than laminated porcelain capacitors.

[0027]

EXAMPLES First, sample N in Table 1, Table 2 and Table 3
o. The case of 1 will be described. Sample No. In No. 1, as a starting material to be used, BaCO with a purity of 99.0% or more was used.
₃ , MgO, ZnO, CaCO ₃ , SrCO ₃ and Ti
A powder of O ₂ is prepared, and the general formula (1-α-β) (Ba _{k- (x + y)} M _x Ly _y ) O _k TiO ₂ + αBaZrO ₃ + β (R _1-z R ′ _Z ) of the basic component is prepared. (Ba _{k- (x + y)} M _x L _y ) O _k TiO ₂ … (2) of the first term in O _3/2 … (1) is (Ba _0.96 Mg _0.03 Zn _0.01 Ca _0.01 Sr _0.01 ) O _1.02 The powder was weighed as follows so that the composition was TiO ₂ (3). BaCO ₃ 1037.78g MgO 6.63g ZnO 4.46g CaCO ₃ 5.48g SrCO ₃ 8.09g TiO ₂ 437.57g After wet-mixing these with a ball mill for about 20 hours,
It was dried at 0 ° C. for 4 hours and then ground. This pulverized product was calcined in the air at about 1200 ° C for 2 hours to obtain the first basic component.
A powder having the composition described in the above item was obtained.

Next, the general formula (1-α-β) (Ba _{k- (x + y)} M _x L _y ) O _k TiO ₂ + αBaZrO ₃ + β (R _1-z R ′ _Z ) O _{3 of} the basic component _In order to obtain the second term BaZrO ₃ in _{/ 2} (1), the powders of BaCO ₃ and ZrO ₂ were weighed as follows. BaCO ₃ 615.61g ZrO ₂ 384.39g These were wet mixed in a ball mill for about 20 hours and then
It was dried at 0 ° C. for 4 hours and then ground. The pulverized product was calcined in the air at about 1250 ° C. for 2 hours to obtain a powder having the above composition.

Next, the general formula (1-α-β) (Ba _{k- (x + y)} M _x L _y ) O _k TiO ₂ + αBaZrO ₃ + β (R _1-z R ′ _Z ) O _{3 of} the basic component _{/ 2} … (1) the third term (R _1-z R ′ _Z ) O _3/2 … (4) becomes (Sm _0.2 Er _0.8 ) O _3/2 … (5) Sm The powders of ₂ O ₃ and Er ₂ O ₃ were weighed as follows. Sm ₂ O ₃ 185.61g Er ₂ O ₃ 814.39g These were wet mixed in a ball mill for about 20 hours and then
It was dried at 0 ° C. for 4 hours and then pulverized to obtain a powder having the above composition.

Sample No. 1-α-β in the general formula (1) of the above basic component in order to obtain the basic component of 1.
Is 0.96 moles, α is 0.02 moles, and β is 0.02 moles, and 96 mole parts (959.74 g) of the component powder of the first item of the basic component and 2 mole parts (23.97 g). ) The powder of the second component of the basic component of 2) and 2 parts by mole (16.29 g)
1000 g by mixing with the powder of the third item of the basic components of
The basic ingredients of

On the other hand, sample No. To obtain a first additive component, were weighed _{Li 2 O 15.87g SiO 2 63.84g CaCO} 3 14.18g SrCO 3 2.61g BaCO 3 3.49g, was added 300cc of alcohol thereto, using alumina balls in a polyethylene pot After stirring for 10 hours, it was calcined in the air at 1000 ° C for 2 hours,
It was put in an alumina pot together with 00 cc of alcohol, pulverized with an alumina ball for 15 hours, and then dried at 150 ° C. for 4 hours to obtain Li ₂ O of 30 mol%, SiO ₂ of 60 mol%, and MO of 10 mol% ( CaO: 8 mol%, S
An additive component having a composition of rO: 1 mol% and BaO: 1 mol% was obtained.

Next, 1000 g (100
10 parts by weight (1 part by weight) of the powder of the above-mentioned additional component is added to the total weight of the basic component and the additional component by adding an organic binder composed of an aqueous solution of an acrylic ester polymer, glycerin and condensed phosphate. On the other hand, 15% by weight was added, and further 50% by weight of water was added, and these were put into a ball mill, pulverized and mixed to prepare a slurry of a porcelain raw material.

Next, the slurry was placed in a vacuum deaerator for defoaming, the slurry was placed in a reverse roll coater, and this was used to form a thin film based on this slurry on a polyester film. On the film 1
It was heated to 00 ° C. and dried to obtain a green sheet having a thickness of about 25 μm. This sheet was punched into a 10 cm square and used.

On the other hand, as the conductive paste for the internal electrodes, 10 g of nickel powder having an average particle size of 1.5 μm and 0.9 g of ethyl cellulose dissolved in 9.1 g of butyl carbitol were placed in a stirrer for 10 hours. Obtained by stirring. This conductive paste was printed on one surface of the green sheet through a screen having 50 patterns each having a length of 14 mm and a width of 7 mm, and then dried.

Next, two green sheets were laminated with the printing surface facing up. At this time, the adjacent upper and lower sheets were arranged such that their printing surfaces were displaced by about half in the longitudinal direction of the pattern. Further, 10 unprinted green sheets were laminated on each of the upper and lower surfaces of this laminate. Next, this laminate was pressed at a temperature of about 50 ° C. by applying a pressure of about 40 tons in the thickness direction. After that, the laminate was cut into a lattice shape to obtain about 50 laminated chips.

Next, this laminated chip was put in a furnace capable of firing in the atmosphere, and heated to 600 ° C. at a rate of 100 ° C./hr in the atmosphere to burn the organic binder. After that,
The atmosphere of the furnace was changed from the atmosphere to an atmosphere of H ₂ (2% by volume) + N ₂ (98% by volume). Then, the furnace is kept in the reducing atmosphere as described above, the heating temperature of the laminated chips is kept from 600 ° C. to the firing temperature of 1150 ° C. (maximum temperature) for 3 hours, and then 600 ° C. at 100 ° C./hr. The temperature was lowered to 0 ° C., the atmosphere was replaced with an air atmosphere (oxidizing atmosphere), the temperature was kept at 600 ° C. for 30 minutes to perform an oxidation treatment, and then the temperature was cooled to room temperature to obtain a sintered body chip.

Next, a conductive paste consisting of zinc, glass frit and vehicle is applied to the side surface of the sintered chip where the electrodes are exposed and dried, and this is baked in the atmosphere at a temperature of 550 ° C. for 15 minutes, A zinc electrode layer was formed, copper was further deposited thereon by electroless plating, and a Pb-Sn solder layer was further provided thereon by electroplating to form a pair of external electrodes.

As a result, a laminated ceramic capacitor 10 including the dielectric ceramic layer 12, the internal electrodes 14, and the external electrodes 16 was obtained as shown in FIG. The thickness of the dielectric ceramic layer 12 of the laminated ceramic capacitor 10 is 0.02 m.
m, the facing area of the internal electrode 14 is 5 mm × 5 mm = 25
It is 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.

Next, when the electrical characteristics of the laminated ceramic capacitor 10 were measured, as shown in Table 3, the relative permittivity ε was obtained.
_s is 3550, tan δ is 1.3%, and resistivity ρ is 6.1.
× 10 ⁶ MΩ · cm, CR product at high temperature is 314 F ·
Ω, -55 ° C and +12 based on the capacitance of 25 ° C
The rate of change in capacitance at 5 ° C. ΔC ₋₅₅ , ΔC ₁₂₅ is −10.
3%, + 3.5%, based on 20 ° C capacitance -2
The change rates ΔC _-25 and ΔC _{85 of the} capacitance at 5 ° C and + 85 ° C were -5.2% and -6.9%, respectively.

The electrical characteristics were measured as follows. (A) the relative dielectric constant epsilon _s is the temperature 20 ° C., a frequency 1 kHz, the capacitance under the condition of the voltage (effective value) 1.0 V was measured, the opposing area of the measured value and a pair of internal electrodes (25 mm ² ) And the thickness of the dielectric porcelain layer between the pair of internal electrodes is 0.02 mm. (B) Dielectric loss tan δ (%) was measured under the same conditions as in the measurement of the relative permittivity. (C) The resistivity ρ (MΩ · cm) is D at a temperature of 20 ° C.
After applying C100V for 60 seconds, the resistance value between the pair of external electrodes was measured, and the resistance value was calculated based on the measured value and the dimension. (D) High temperature CR product (F · Ω) is 150 ° C and frequency is 1
Capacitance is measured under the condition of kHz and voltage (effective value) of 1.0 V, and then 100 V DC is applied for 60 seconds, and then a resistance value between a pair of external electrodes is measured to measure the capacitance. The product of the resistance value and the resistance value was calculated. (E) For the temperature characteristics of capacitance, put the sample in a constant temperature bath,
55 ° C, -25 ° C, 0 ° C, + 20 ° C, + 25 ° C, +50
At each temperature of ℃, + 85 ℃, + 110 ℃, and + 125 ℃, measure the capacitance under the condition of frequency 1kHz and voltage (effective value) 1.0V. It was obtained by calculating the rate of change in capacitance at each temperature.

As described above, the sample No. The method for producing No. 1 and its characteristics are described above. For 2-94,
The composition and proportions of the basic component and the additive component, and the firing temperature were changed. A laminated porcelain capacitor was prepared by the same method as in Example 1, and the electrical characteristics were measured by the same method.

Tables 1 to 1 show the compositions and proportions of the basic components for each sample, and Tables 2 to 2 show the compositions and proportions of the additive components for each sample, and Tables 3 to 3 show. Shows the firing temperature and the electrical characteristics of the laminated ceramic capacitor for each sample.

The numerical values in the x, y, and k columns of Tables 1 are the numbers of atoms of each element of the compositional formula (2) of the basic component described above, that is, the number of atoms of TiO ₂ is 1. The ratio of the number of atoms of each element is shown. Further, the numerical values in the columns 1-z and z in Tables 1 show the ratio of the number of atoms of each element of the composition formula (4) of the basic component described above.

In addition, Mg, Zn in the column x of Tables 1 to
Indicates the content of M in the composition formula (1) of the basic component described above, Ca and Sr in the y column indicate the content of L in the composition formula (1) of the basic component, and La in the 1-z column. , Ce, Pr, N
d, Pm, Sm, and Eu represent the contents of R in the composition formula (1) of the above-mentioned basic components, and Sc, Y, Gd, T in the column of z.
b, Dy, Ho, Er, Tm, Yb and Lu represent the contents of R'of the composition formula (1) of the basic component described above.

The addition amounts of the additive components in Table 2 are shown in parts by weight based on 100 parts by weight of the basic component. In the column of MO of the additive component, the proportions of BaO, SrO, CaO, MgO and ZnO are shown in mol%.

In Tables 3 to 5, the temperature characteristics of the electrostatic capacitance are -55 ° C and +12 based on the electrostatic capacitance of 25 ° C.
Change the rate of change of capacitance at 5 ℃ by ΔC _-55 (%) and ΔC ₁₂₅
(%) The change rate of the capacitance of -25 ° C and + 85 ° C based on the capacitance of 20 ° C is ΔC _-25 (%) and ΔC.
It is indicated by ₈₅ (%).

[0047]

[Table 1]

[0048]

[Table 1]

[0049]

[Table 1]

[0050]

[Table 1]

[0051]

[Table 1]

[0052]

[Table 2]

[0053]

[Table 2]

[0054]

[Table 2]

[0055]

[Table 2]

[0056]

[Table 2]

[0057]

[Table 3]

[0058]

[Table 3]

[0059]

[Table 3]

[0060]

[Table 3]

[0061]

[Table 3]

As is clear from Table 1, Table 2 and Table 3, the samples according to the present invention have a relative dielectric constant ε _s of 3300 or more when fired at 1200 ° C. or less in a non-oxidizing atmosphere. Tan δ is 2.5% or less, resistivity ρ is 4.0 × 10 ⁶ MΩ · cm or more, CR product at 150 ° C. is 200 F · Ω or more, and temperature change rate of capacitance ΔC
_-55 and ΔC ₁₂₅ are within -15% to + 15%, ΔC _-25
And ΔC ₈₅ can obtain a dielectric ceramic composition or a ceramic capacitor having electrical characteristics within −10% to + 10%.

On the other hand, sample No. 19, 24, 2
5,27-29,32,33,37-39,43,4
4,49,57,61-63,65,67,78-84
According to the samples Nos. 89 and 89, it is not possible to obtain a porcelain capacitor having desired electrical characteristics. Therefore, these No. Samples are outside the scope of the present invention.

Tables 3 to 3 show the temperature change rate ΔC of capacitance.
Only _-55 , ΔC ₁₂₅ , ΔC _-25 , and ΔC ₈₅ are displayed, but in the sample according to the present invention, the temperature change rate ΔC of the capacitance in the range of −25 ° C. to + 85 ° C. is −10% to +10. %
The temperature change rate ΔC of the capacitance in the range of −55 ° C. to + 125 ° C. is −15% to + 15%.
Is within the range.

Next, the proper range of the composition of the dielectric ceramic composition used in the ceramic capacitor according to the present invention will be examined with reference to the experimental results shown in Table 1, Table 2 and Table 3. .. First, consider the value of x + y. The value of x + y is the sample No. As shown in Nos. 20 and 21, in the case of 0.01, a dielectric ceramic composition having desired electrical characteristics can be obtained. As shown in FIG. 19, in the case of 0, the temperature change rate ΔC of the electrostatic capacitance
_-55 deviates from -15% to + 15%. Therefore, x + y
The lower limit value of is 0.01.

Further, the value of x + y is the sample No. 30, 3
As shown in FIG. 1, in the case of 0.10, a dielectric ceramic composition having desired electrical characteristics can be obtained.
As shown in 25, 27 and 29, in the case of 0.11,
The temperature change rate ΔC _{85 of} capacitance deviates from −10% to + 10%. Therefore, the upper limit value of x + y is 0.10.

However, the sample No. 24 and 28, when the value of y exceeds 0.05, the temperature change rate ΔC _{85 of the} capacitance is −10% to + even if x + y ≦ 0.10.
It is out of 10%. Therefore, the range of x + y is
0.01 ≦ x + y ≦ 0.10, but at the same time, y ≦
Must be 0.05.

It should be noted that Mg and Zn as the M component work almost in the same manner, and one or both of Mg and Zn can be used within a range satisfying 0 ≦ x ≦ 0.10. Ca and Sr work almost in the same manner, and one or both of Ca and Sr can be used in a range satisfying 0 ≦ y ≦ 0.05. However, in either case of one or more kinds of the M component and the L component, the range of x + y must be 0.01 ≦ x + y ≦ 0.10.

Next, the value of k will be examined. The value of k is the sample No. As shown in No. 34, when 1.00, a dielectric ceramic composition having desired electrical characteristics can be obtained. 32 and 33, k <1.00
In the case of, the resistivity ρ is significantly smaller than 4.0 × 10 ⁶ MΩ · cm, and the temperature change rate of the capacitance ΔC ₋₅₅ , Δ.
C _{12 5} disengages from -15% ~ + 15%, ΔC -25, ΔC
₈₅ deviates from -10% to + 10%, and C at 150 ° C
The R product will be much smaller than 200 F · Ω. Therefore, the lower limit value of k is 1.00.

Further, the value of k is the value of the sample No. As shown in FIG. 36, when k = 1.05, a dielectric porcelain composition having desired electrical characteristics can be obtained. As shown in 37 and 38, when k> 1.05, a dense sintered body cannot be obtained even by firing at 1250 ° C. Therefore, the upper limit of k is 1.05.

Next, the value of α will be examined. The value of α is the sample No. As shown in 40, when 0.005, a dielectric ceramic composition having desired electrical characteristics can be obtained.
Sample No. As shown in 39, when α = 0, the temperature change rate ΔC _{−55 of the} capacitance deviates from −15% to + 15%, and ΔC ₋₂₅ deviates from −10% to + 10%.
Therefore, the lower limit value of α is 0.005.

Further, the value of α is the sample No. 42, in the case of 0.04, a dielectric ceramic composition having desired electric characteristics can be obtained. As shown in 43, in the case of 0.05, ΔC ₈₅ is −10% to + 10%.
Will fall out of. Therefore, the upper limit value of α is 0.04.

Next, the value of β will be examined. The value of β is the sample No. As shown in 45, when 0.002, a dielectric ceramic composition having desired electric characteristics can be obtained.
Sample No. As shown in 44, when 0, the resistivity ρ
Is less than 4.0 × 10 ⁶ MΩ · cm, 150 ° C
The CR product at is less than 200 F · Ω. Therefore, the lower limit value of β is 0.002.

The value of β is the same as the sample No. As shown in FIG. 48, when 0.04, a dielectric ceramic composition having desired electrical characteristics can be obtained. As shown in 49, in the case of 0.05, a dense sintered body cannot be obtained by firing at 1250 ° C. Therefore, the upper limit of β is 0.04.

Next, the value of z will be examined. The value of z is the sample No. As shown in Nos. 60 and 66, in the case of 0.5, the dielectric ceramic composition having desired electric characteristics can be obtained. 61, 62, 65, 67,
When z <0.5, tan δ exceeds 2.5%, the resistivity ρ becomes smaller than 4 × 10 ⁶ , and 150 ° C.
The CR product at the bottom is significantly smaller than 200 F · Ω, and the temperature change rate of capacitance ΔC ₋₅₅ , ΔC ₁₂₅ is −15.
%-+ 15%, ΔC _-25 , ΔC ₈₅ -10%-
It deviates from + 10%. Therefore, the lower limit of z is 0.
It is 5.

The value of z is the same as that of sample No. 58 and 64, when it is 0.90, the dielectric ceramic composition having desired electric characteristics can be obtained. 57, 63
As shown in, the relative permittivity ε _s is 3 when 0.95.
Below 300, CR product at 150 ℃ is 200F
・ It becomes less than Ω. Therefore, the upper limit of z is 0.9
It is 0.

The R component La, CE, Pr, Nd,
Pm, Sm and Eu as well as Sc, Y and G of R'component
Each of d, Tb, Dy, Ho, Er, Tm, Yb and Lu works in the same manner, and the same effect can be obtained by using one selected from these or a combination of a plurality of them. It is what is done.

However, the value of z is 0. regardless of whether each of the R component and the R'component is one kind or plural kinds.
It is desirable that the range is 5 ≦ z ≦ 0.9. Also, R
The component and the R ′ component contribute to the improvement of the CR product at high temperature by combining in the range of z value of 0.5 ≦ z ≦ 0.9. That is, by adding the R component and the R'component in combination within the above range,
It is possible to make the CR product below 200 FΩ or more

Next, the proper range of the addition amount of the additive component will be examined. The addition amount of the additive component is the same as the sample As shown in No. 85, in the case of 0.2 parts by weight with respect to 100 parts by weight of the basic component, firing at 1190 ° C. gives a dielectric ceramic composition having desired electrical characteristics. As shown in 84, when the amount of the basic component is 0 part by weight relative to 100 parts by weight, a dense sintered body cannot be obtained even by firing at 1250 ° C.
Therefore, the lower limit of the added amount of the additive component is 0.2 part by weight with respect to 100 parts by weight of the basic component.

Further, the addition amount of the additive component is the same as the sample No. 8
As shown in FIG.
In the case of parts by weight, it is possible to obtain a dielectric ceramic composition having desired electrical characteristics. As shown in 89, in the case of 7.0 parts by weight with respect to 100 parts by weight of the basic component, the relative dielectric constant is less than 3300, and the temperature change rate of capacitance ΔC ₋₅₅ is from −15% to + 15%. It will come off. Therefore, the upper limit of the addition amount of the additive component is 10
It is 5.0 parts by weight with respect to 0 parts by weight.

Next, the composition range of the additive component is Li ₂ O--
Triangle diagram showing the composition ratio of SiO ₂ -MO in mol% (Fig. 2)
Is a range surrounded by five straight lines connecting the first to sixth points A to E in order. The first point A in the triangular diagram is the sample No.
68, 1 mol% of Li ₂ O and 8 of SiO ₂
The composition of 0 mol% and MO is 19 mol%, the second point B
Is the sample No. 69, Li ₂ O has a composition of 1 mol%, SiO ₂ has a composition of 39 mol%, and MO has a composition of 60 mol%. As shown at 70, L
i ₂ O is 30 mol%, SiO ₂ is 30 mol%, and MO is 4
The fourth point D is the sample No. 71
As shown in, the Li ₂ O content is 50 mol% and the SiO ₂ content is 50 mol%.
The fifth point E is a composition in which the mol% and the MO are 0 mol%.
Sample No. 72, 20 mol% of Li ₂ O,
The composition is 80 mol% of SiO _{2 and} 0 mol% of MO.

Sample No. 68-77,
The composition range of the additional components is the _{first to} fifth points A to A of the triangular diagram (FIG. 2) showing the composition ratio of Li ₂ O—SiO ₂ —MO in mol%.
Desired electrical characteristics can be obtained within the range surrounded by the five straight lines connecting E in order. 78-
As shown in 83, if the composition range of the additive component is out of the above range, a dense sintered body cannot be obtained even by firing at 1250 ° C.

The MO component is the sample No. 90-94
As shown in, BaO, SrO, CaO, MgO, Zn
Any one of O may be used, or an appropriate ratio of two or more may be used as shown in other samples.

[0084]

According to the present invention, a laminated ceramic capacitor manufactured using the dielectric ceramic composition having the composition according to the present invention has a relative dielectric constant ε _s of 3300 or more and a dielectric loss tan δ of 2.5% or less. , The resistivity ρ is 4.0 × 10 ⁶ MΩ · cm or more, the CR product at 150 ° C. is 200 F · Ω or more, and the capacitance temperature change rate is −55 ° C. to 125 ° C.
-15% to + 15% (based on 25 ° C), -25 ° C to 8
It can fall within the range of -10% to + 10% (referenced to 20 ° C) at 5 ° C, and especially CR at high temperature.
It is possible to provide a porcelain capacitor provided with a dielectric porcelain composition having a large product.

[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 symbols]

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

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

Claims (2)

[Claims] 1. A porcelain capacitor comprising one or more dielectric porcelain layers made of a dielectric porcelain composition and at least two or more internal electrodes sandwiching the dielectric porcelain layer, wherein: The porcelain composition is formed by firing a mixture of 100.0 parts by weight of the basic component and 0.2 to 5.0 parts by weight of the additive component, and the basic component is (1-α-β) ( Ba _{k- (x + y)} M _x L _y ) O _k TiO ₂ + αBaZrO ₃ + β (R _1-z R ′ _Z ) O _3/2 (where M is Mg and / or Zn, L is Ca and / or Sr and R are one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu, and R ′.
Is Sc, Y, Gd, Tb, Dy, Ho, Er, Tm,
One or more elements selected from Yb and Lu, α, β, k, x, y, z are 0.005 ≦ α ≦ 0.04 0.002 ≦ α ≦ 0.04 1.00 ≦ k ≦ 1.050 0 ≦ x <0.10 0 ≦ y ≦ 0.05 0.01 ≦ x + y ≦ 0.10 0.5 ≦ z ≦ 0.9) The additive components are Li ₂ O, SiO ₂ and MO (however, MO
Is one kind or two or more kinds of oxides selected from BaO, SrO, CaO, MgO and ZnO), and the composition range of Li ₂ O, SiO ₂ and MO is %, 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 firing the laminate in a non-oxidizing atmosphere, and a step of heat-treating the fired laminate in an oxidizing atmosphere, The mixture of unsintered porcelain powder is composed of 100.0 parts by weight of the basic component and 0.2 to 5 parts by weight of the additional component, and the basic component is (1-α-β) (Ba _{k -(x + y)} M _x L _y ) O _k TiO ₂ + αBaZrO ₃ + β (R _1-z R ′ _Z ) O _3/2 (where M is Mg and / or Zn, L is Ca and / or Sr, R is one or more elements selected from La, Ce, Pr, Nd, Pm, Sm and Eu, and R ′.
Is Sc, Y, Gd, Tb, Dy, Ho, Er, Tm,
One or more elements selected from Yb and Lu, α, β, k, x, y, z are 0.005 ≦ α ≦ 0.04 0.002 ≦ α ≦ 0.04 1.00 ≦ k ≦ 1.050 0 ≦ x <0.10 0 ≦ y ≦ 0.05 0.01 ≦ x + y ≦ 0.10 0.5 ≦ z ≦ 0.9) 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 Li ₂ O, SiO ₂ and MO is %, 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.