JPH03278423A - Porcelain capacitor and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve relative permittivity by mixing 100 pts.wt. of specific basic component, and 0.2-5 pts.wt. of specific additive component of a specific range of a triangular diagram of mol% of composition range, and firing the mixture. CONSTITUTION:100 pts.wt. of basic component represented by formula I and 0.2-5 pts.wt. of additive component containing Li2O, SiO2 and MO (MO is metal oxide of one or more types selected from BaO, SrO, CaO, MgO and ZnO) are mixed and fired. The composition range of the additive component is disposed in a range surrounded by straight lines for sequentially coupling points A-B-C-D- E-A of a triangular diagram shown by mole % of the composition range of the additive component, and hence its relative permittivity can be set to 3000 or more. In the formula I, M; Mg and/or Zn, L; Ca and/or Sr, R; metal of one or more types selected from Sc, Y, Gd, Dy, Ho, Er, Yb, Tb, Tm, Lu. Letters alpha, k, x, z, y; numerical values for satisfying formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a ceramic capacitor having a single-layer or laminated structure in which a dielectric ceramic layer is sandwiched between at least two internal electrodes, and a method for manufacturing the same. .

[Prior Art] Conventionally, when manufacturing multilayer ceramic capacitors, a conductive paste of noble metal such as platinum or palladium is printed in a desired pattern on an unsintered porcelain sheet (green sheet) made of dielectric porcelain raw material powder. A plurality of these sheets were stacked and pressed together, and fired at 1300° C. to 1600° C. in an oxidizing atmosphere.

Through this firing, the unsintered porcelain sheet made of the dielectric porcelain raw material powder becomes a dielectric porcelain layer, and the conductive paste of noble metal such as platinum or palladium becomes an internal electrode.

As mentioned above, if a conductive paste containing a noble metal such as platinum or palladium is used as the main component, the desired internal electrode can be obtained even if it is fired at a high temperature of 1300°C to 1600°C in an oxidizing atmosphere. I can do it.

However, since precious metals such as platinum and palladium are expensive, the cost of multilayer ceramic capacitors has inevitably increased.

Japanese Patent Publication No. 14607/1983, filed by the applicant, discloses (B
ai+-X MmlOk TiOf (where M is Mg and/or Zn), and LitO
and an additive component consisting of S i O* is disclosed.

In addition, Japanese Patent Publication No. 61-14608 discloses that the dielectric ceramic composition described in Japanese Patent Publication No. 61-14607 is
ig, O and S i k instead of Oa, Lig O, Si
ng and MO (however, MO is Bad, CaO and SrO
A dielectric ceramic composition is disclosed that includes an additive component consisting of one or more metal oxides selected from the following.

In addition, in Japanese Patent Publication No. 14609/1983, (Bak
-Il-, M, L, )O, TiO- (where M is Mg and/or Zn, L is Sr and/or Ca) and an additive component consisting of Li2O and SiO□. A dielectric ceramic composition is disclosed.

Furthermore, Japanese Patent Publication No. 61-14610 discloses that k, L l x
O, S i 02 and MO (However, MO is Bad, Ca
A dielectric ceramic composition is disclosed that includes an additive component consisting of one or more metal oxides selected from O and SrO.

In addition, in Japanese Patent Publication No. 14611/1983, (B ai
+-m M, loh T i ox (However, M is M
g.

one or more metal elements selected from Zn, Sr and Ca), B2O3 and Si
A dielectric ceramic composition is disclosed that includes an additive component consisting of Ox.

In addition, in Japanese Patent Publication No. 1595/1983, (B a 1
l-II Mll)O* T L Oz Ndanshi, M
is Mg.

one or more metal elements selected from Zn, Sr and Ca); and B20. and MO(
However, MO is Bad.

A dielectric ceramic composition containing an additive component consisting of one or more metal oxides selected from MgO, ZnO, SrO, and CaO is disclosed.

In addition, Japanese Patent Publication No. 1596/1983 describes the B2O of the dielectric ceramic composition described in Japanese Patent Publication No. 1595/1982.
3 and k, B, O, instead of MO.

5iO- and MO (however, MO is BaO.

A dielectric ceramic composition containing an additive component consisting of one or more metal oxides selected from MgO, ZnO, SrO, and CaO is disclosed.

If the dielectric ceramic composition disclosed in these documents is used as a dielectric layer, it can be heated to 1200°C in a reducing atmosphere.
Porcelain capacitors can be obtained by firing at the following temperatures:
Moreover, the relative permittivity of the dielectric ceramic composition is 2000 or more, and the temperature change rate of the relative permittivity is 1 at -25°C to +85°C.
It can be set in the range of 0%.

[Problems to be solved by the invention] By the way, with the increasing density of electronic circuits in recent years,
The demand for miniaturization of ceramic capacitors is very strong (there is a desire to develop a ceramic capacitor with a dielectric ceramic composition having a dielectric constant even higher than the dielectric ceramic composition disclosed in the above publications). Ta.

In addition, since ceramic capacitors are used in various environments, they are equipped with a dielectric ceramic composition that has a smaller rate of change in relative dielectric constant over a wider temperature range than the dielectric ceramic compositions disclosed in the above-mentioned publications. There was a desire to develop a ceramic capacitor that would

Therefore, the object of the present invention is to
Although it is obtained by firing at a temperature of 1200°C or less, it has a relative dielectric constant of 3000 or more and a dielectric loss ta.
nδ is 2.5% or less, resistivity ρ is 1X10'Ω・cm or more, and the temperature change rate of relative dielectric constant is 155℃ to 125℃
-15% to +15% (based on 25℃), -25℃ to 8
It is an object of the present invention to provide a ceramic capacitor equipped with a dielectric ceramic composition that falls within the range of =10% to +10% (based on 20°C) at 5°C, and a method for manufacturing the same.

[Means for Solving the Problems] A ceramic capacitor according to the present invention includes a dielectric ceramic layer made of a dielectric ceramic composition, and at least two internal electrodes sandwiching the dielectric ceramic layer. In the ceramic capacitor, the dielectric ceramic composition comprises 100 parts by weight of a basic component;
It is made by firing a mixture with 0.2 to 5 parts by weight of additional components, and the basic components are (l-a l (1-m-xMxLz)Oll(Tt+
-yRylOt-yzx)+αBaZr0s (However, M is Mg and/or Zn, L is Ca and/or Sr, and R is Sc, Y, Gd, Dy.

1 selected from Ho, Er, Yb, Tb, Tm, Lu
species or two or more metals, α, k, x.

Z, y are 0, 005 ≦ α ≦0, 041, 00 ≦
to ≦ 1, 05 0<x<0. 10 0<z≦0.05 0,01≦x+z≦0.10 o<y≦0.04), and the additive components are L i 20, Sing, and MO (however, MO is B
one or more metal oxides selected from ad, SrO, Cab, MgO and ZnO), and the composition range of the Li x O, the SiO2 and the MO is such that these compositions are In the triangular diagram shown in %, LL, ○ is 1 mol%, Stow is 80 mol%,
A first point A having a composition of 19 mol% of the MO, and a second point B having a composition of 1 mol% of the L i z O, 39 mol% of the SiO2, and 60 mol% of the MO. , a third point C showing a composition of 30 mol% of Li, O, 30 mol% of S i OZ, and 40 mol% of MO;
mol%, a fourth dot showing a composition in which the MO is 0 mol%;
MO is located in a region surrounded by five straight lines connecting in this order the fifth point E showing a composition of 80 mol % MO and 0 mol % MO.

Here, the reason why 0.005≦α≦0.04 is set is that α is 0.
．． A dielectric ceramic composition having desired electrical properties can be obtained in the range of 005≦a≦0.04, but when α is 0.
．． When it becomes less than 005, the temperature change rate of capacitance ΔC-2
, outside the range of -10% to +10%, ΔC-all is -11
If it is outside the range of 5% to +15% and a exceeds 0.04, the capacitance temperature change rate ΔC115 will be -10% to +1
This is because it is outside the 0% range.

Also, the reason why we set 1.00≦≦1.05 is that k is 1.0
In the range of 0≦≦1.05, a dielectric ceramic composition having desired electrical properties can be obtained, but when k is 1.00
This is because when k is less than 1.05, the resistivity ρ becomes significantly lower than 1×lO'MΩ·cm, and when k exceeds 1.05, a dense sintered body cannot be obtained.

Also, o, oi≦x+z≦0.10 is set because x+z
In the range of 0.01≦x+z≦0.10, a dielectric ceramic composition with desired electrical properties can be obtained;
When becomes less than 0.01, the temperature change rate of capacitance ΔC-
0 outside the range of -10% to +10%, △C-5s is -15
%~+15%<7) Out of range, x+z'b'0. l
.

When the temperature change rate ΔCsgr of capacitance exceeds 110
This is because it is outside the range of % to +10%.

However, even if X+Z is in the range o, oi≦x+z≦0.10, if Z exceeds 0.05, a dielectric ceramic composition having desired electrical properties cannot be obtained. Therefore, the upper limit values of X+Z are o and io, but at the same time the upper limit value of Z must be set to 0.05.

In addition, Mg and Zn of the M component and Ca and Sr of the L component are f
Working in the same way, one or both of Mg and Zn can be used within the range that satisfies 0<x<0.10, and O<z
One or both of Ca and Sr can be used within a range satisfying ≦0.05.

It is desirable that the value of X+Z be in the range of 0.01 to 0.10 in either case of one or more of the M component and the L component.

Also, the reason why o<y≦0.04 is set is that y is o<y≦0.
If y is in the range of 0.04, a dielectric ceramic composition with desired electrical properties can be obtained, but if y exceeds 0.04, a dense sintered body cannot be obtained.

Then, the R components Sc, Y, Dy, and Ho.

Er, Yb work in the same way as f, and 1 selected from these
Similar results can be obtained using one or more. Regardless of whether there is one type of R component or multiple types of R components, it is desirable that the value of y be in the range of 0.04 or less. Further, as long as y is 0.0-4 or less, even a small amount close to 0 will have a certain effect.

In the composition formula, the component represented by R contributes to improving the temperature characteristics of capacitance. That is, by adding the R component, the temperature
Temperature change rate of capacitance ΔC-8S to Δ in the range of 25℃
CI! 11 can be easily kept in the range of -15% to +15%, and the temperature change rate of capacitance ΔC-0 to ΔCas in the range of -25°C to 85°C can be easily kept in the range of -10% to +15%.
It becomes possible to easily keep the capacitance within the range of +10%, and it is possible to reduce the fluctuation range of the temperature change rate of capacitance in each temperature range.

Further, the R component has the effect of increasing the resistivity ρ and the effect of increasing the sinterability.

In addition, in the composition formula showing the basic components, X.

y and z indicate the number of atoms of each element, and 1-0 and α are team-++-+tMxLzlOm (TI+-yR
The ratio of ylOz-F/2 to Barrow in the second term is shown in moles.

In addition, among the basic components, a trace amount of Mn0a (preferably 0.05 to 0.1% by weight) is added within a range that does not impede the purpose of the present invention.
) may be added to improve sinterability. Further, other substances may be added as necessary.

In addition, the starting materials for obtaining the basic components may be other than those shown in the examples, for example, B a O * S r O + CaO
It may be used as an oxide or hydroxide or other compounds.

Next, add 0 parts of added ingredients to 100 parts by weight of the basic ingredients.
．． The content was set in the range of 2 to 5 parts by weight.

When the additive component is in the range of 0.2 to 5 parts by weight, a dielectric ceramic composition having desired electrical properties can be obtained.
When the added component is less than 0.2 parts by weight, the firing temperature is 12
Even at 50°C, a dense sintered body cannot be obtained, and if the added component exceeds 5 parts by weight, the relative dielectric constant ε becomes less than 3000, and the temperature change rate ΔCas of capacitance decreases from -10% to
This is because it is outside the range of +1.0%.

In the triangular diagram showing the composition of L iz O, SiO2, and MO in mol%, the composition of the additive components is shown in the above-mentioned Nos. 1 to 5.
The reason why points A-E are placed in the area surrounded by five straight lines connecting them in order is that if the composition of the additive components is within this area, a dielectric ceramic composition having desired electrical properties can be obtained. However, if the composition of the additive components falls outside this range, a dense sintered body cannot be obtained.

Note that the MO acid components are Bad, MgO, and ZnO.

It may be either one of SrO or CaO, or it may be in an appropriate ratio. Further, the starting materials for the additive components may be other compounds such as oxides and hydroxides other than those shown in the examples.

Next, the method for manufacturing a porcelain capacitor according to the present invention includes the steps of preparing a mixture of unsintered porcelain powder consisting of the above-mentioned basic components and additive components, and forming an unsintered porcelain sheet consisting of the mixture. a step of forming a laminate in which the unsintered porcelain sheet is sandwiched between at least two conductive paste films; a step of firing the laminate in a non-oxidizing atmosphere; The method includes a step of heat-treating the laminate in an oxidizing atmosphere.

Here, the firing temperature in the non-oxidizing atmosphere can be varied depending on the electrode material.

When using nickel as the internal electrode, the temperature is 1050℃~12
Almost no aggregation of nickel particles occurs in the temperature range of 00°C. Further, the non-oxidizing atmosphere may be not only a reducing atmosphere such as H2 or C○, but also a neutral atmosphere such as N2 or Ar.

Furthermore, the temperature of the heat treatment in the oxidizing atmosphere can be varied in consideration of the electrode material such as nickel and the oxidation of the ceramic.

Although the temperature of this heat treatment was set to 600°C in the example, it is not limited to this, and may be any temperature lower than the sintering temperature (preferably in the range of 500°C to 1000°C).

Note that the present invention is of course applicable to general single-layer ceramic capacitors other than multilayer ceramic capacitors.

[Example 1] First, the preparation method of sample No. 1 in Table 1 and its electrical characteristics will be explained.

Each of the compounds in formulation 1 was weighed, and these compounds were added to a pot mill (pot +5ill), along with alumina balls and 2.51 g of water, and mixed with stirring for 15 hours to obtain a raw material mixture.

Here, the weight (g) and molar parts of the compound of formulation 1 are 1-++-zMJzlom(Tl+-yRylOz-y
zz (hereinafter referred to as the first basic component) is (B a o
, *aM go, asS r o, or) Or
,ot (Tio,eeYbo,or) 01
．． This value was calculated to be 99g.

Next, put this raw material mixture into a stainless steel pot, dry it at 150°C for 4 hours using a hot air dryer, coarsely crush this dried raw material mixture, and use a tunnel furnace to crush this coarsely crushed raw material mixture. The powder was calcined for 2 hours at about 1200° C. to obtain a powder of the first basic component in the composition formula (1) of the above basic component.

In addition, BaZr0a in the second term of the basic component compositional formula (1)
(hereinafter referred to as the second basic component), k, B a
k so that COs and Zr0z are equimolar, and the former is 6
Weighed 15.61g and 384.39g of the latter, respectively,
After mixing, drying and pulverizing these materials, they were calcined in the atmosphere at about 1250° C. for 2 hours.

Then, as shown in Sample No. 1 in Table 1, k, 98 mol parts (976,15 g) of powder of the first basic component so that k, 1-a is 0.98 mol, and α is 0.02 mol. and 2 mole parts (23.85 g) of powder of the second basic component were mixed to obtain 1000 g of the basic component.

In addition, the compounds of Formulation 2 were each weighed and mixed, 300 cc of alcohol was added to this mixture, and the mixture was stirred for 10 hours using an alumina ball in a polyethylene pot.
Thereafter, it was calcined in the air at a temperature of 1000° C. for 2 hours.

Here, the weight (g) of the compound of formulation 2 is L L z
O is 1 mol%, S i O2 is 80 mol%, MO is 19
This value was calculated so that the composition would be mol % (Bad (3.8 mol % 1 + Ca0 (9.5 mol % 1 + Mgof 5.7 mol %)).

Next, put the material obtained by the above calcination into an alumina pot with 300cc of water, and use an alumina ball to
The powder was pulverized for a period of time, and then dried at 150° C. for 4 hours to obtain a powder of the additive component.

Note that the proportions of Bad, CaO, and MgO, which are the contents of MO, are k, 20 mol%, 50 mol%, and 30 mol%, as shown in Table 1.

L1 Uni-511 order k, 100 parts by weight (1000 g) of the basic component k,
2 parts by weight (20 g) of the above additive components were added, and an organic binder consisting of an aqueous solution of acrylic acid ester polymer glycerin and condensed phosphate was added in an amount of 15% by weight based on the total weight of the basic components and additive components. Then, 50% by weight of water was added, and these were placed in a ball mill to be ground and mixed to prepare a slurry of porcelain raw materials.

The above slurry was degassed by putting it into a vacuum defoaming machine, and the slurry was put into a reverse roll coater, and the thin film molded product obtained therefrom was continuously coated on a long polyester film. I let him take it, and on the same film I gave him 100.
It was dried by heating to 0.degree. C. to obtain an unsintered porcelain sheet with a thickness of about 25 .mu.m. This sheet is long and is used by cutting it into 10 cm squares.

On the other hand, the conductive paste for internal electrodes has an average particle size of 1.5
10g of μm nickel powder and 0.9g of ethyl cellulose
g dissolved in 9.1 g of butylcarpitol were placed in a stirrer and stirred for 10 hours. Then, this conductive paste was printed on one side of the unsintered porcelain sheet through a screen having 50 patterns of 14 mm in length and 7 mm in width, and then dried.

Layer order of unsintered magnetic sheets: Two unsintered ceramic sheets were laminated with the above-mentioned printed side facing up. At this time, the adjacent upper and lower sheets were arranged so that their printed surfaces were shifted by about half in the longitudinal direction of the pattern. Furthermore, four unsintered porcelain sheets each having a thickness of 60 μm were laminated on the upper and lower surfaces of this laminate.

The laminate is heated at a temperature of about 50°C for about 40° in the thickness direction.
The laminate was crimped under a load of 1,000 tons, and then the laminate was cut into a lattice shape to obtain 50 laminate chips.

After the formation of the layered chips, this stacked chip was placed in a furnace capable of firing in an atmosphere, and heated to 600°C at a rate of 100°C/h in an air atmosphere.
The organic binder was burned.

After that, the atmosphere of the furnace was changed from the atmosphere to H2 (2% by volume) + N.
, (98% by volume). Then, while maintaining the furnace in this reducing atmosphere, the heating temperature of the stacked chips was increased from 600°C to the sintering temperature of 1130°C.
Raise the temperature at a rate of 100°C/h to 1130°C (maximum temperature)
After holding for 3 hours, the temperature was lowered to 600°C at a rate of 100°C/h, the atmosphere was changed to an air atmosphere (oxidizing atmosphere), and 600°C was held for 30 minutes to perform oxidation treatment.
Thereafter, it was cooled to room temperature to obtain a laminated sintered body chip.

Outside JLiL, zinc, glass frit, and vehicle (
A conductive paste consisting of a vehicle) was applied and dried, and this was baked in the air at a temperature of 550°C for 15 minutes to form a zinc electrode layer, and then a copper layer was further formed on this using an electroless plating method. , and then on top of this, Pb-
A 5N solder layer was provided to form a pair of external electrodes.

As a result, as shown in FIG. 1, the three dielectric ceramic layers 1
2 and two layers of internal electrodes 14.
A multilayer ceramic capacitor 10 was obtained in which a pair of external electrodes 16 were formed on the capacitor 5.

Here, the external electrode 16 includes a zinc electrode layer 18, a copper layer 20 formed on the zinc electrode layer 18, and a copper layer 20 formed on the zinc electrode layer 18.
and a Pb-3n solder layer 22 formed on top of the Pb-3n solder layer 22.

Note that the dielectric ceramic layer 12 of this multilayer ceramic capacitor 10
The thickness of the dielectric ceramic layer 12 is 0.02 mm, and the opposing area of the pair of internal electrodes 14 is 5 mm x 5 mm = 25 mm.The composition of the dielectric ceramic layer 12 after sintering is determined by mixing the basic components and additive components before sintering. The composition is substantially the same.

Measure the electrical characteristics of the multilayer ceramic capacitor 10,
When the average values were calculated, as shown in Table 2, the dielectric constant ε1 was 3800, tan δ was 1.0%, and resistivity ρ was 6.
．． 2X10"MΩ'cm.

-55℃ and +125℃ based on capacitance at 25℃
The rate of change in capacitance Δc -IIsΔC1□ is -9,5
%, +4.0%, -25 based on capacitance at 20°C
℃, rate of change in capacitance at +85℃ ΔC-21! +ΔC
ss is -5.0%.

=5.6%.

Note that the electrical characteristics were measured in the following manner.

(A) The relative permittivity ε6 is at a temperature of 20°C, a frequency of 1kHz,
! Pressure (effective value) 1. The capacitance was measured under OV conditions, and the measured value and the opposing area of the pair of internal electrodes 14, 25 m
m'' and the thickness of the dielectric ceramic layer 12 between the pair of internal electrodes 14, O-02 mm.

fB) Dielectric loss tan δ (%) was measured under the same conditions as the above measurement of relative dielectric constant.

(C) Resistivity p (MΩ・cm) is measured after applying DClooV for 1 minute at a temperature of 20°C.
The resistance value between them was measured and calculated based on this measured value and the dimensions.

The temperature characteristics of fDl capacitance are as follows: -55°C, -25°C, 0°C, +20°C when the sample is placed in a constant temperature bath.

+25℃, +40℃, +60℃, +85℃.

At temperatures of +105°C and +125°C.

Frequency: 1 kHz, voltage (effective value): 1. The capacitance was measured under OV conditions, and the rate of change at each temperature with respect to the capacitance at 20°C and 25°C was obtained.

The preparation method of samples No. 1 and their characteristics have been described above, but for samples No. 022 to 101, the compositions of the basic components and additive components, their ratios, and the firing temperature in a reducing atmosphere are shown in Table 1. A multilayer ceramic capacitor was prepared in exactly the same manner as the sample N001, except for the changes shown in Table 2, and the electrical characteristics were measured in the same manner.

Table 1 shows the composition of the basic components and additive components of each sample, and Table 2 shows the firing temperature and electrical characteristics of each sample.

In addition, 1-a and α in the basic component column of Table 1 indicate the ratio of the first basic component to the second basic component in moles, and k-x-z, x
, z indicates the ratio of the number of atoms of each element in the compositional formula (1) of the basic components described above.

In addition, Mg and Zn in the X column indicate the content of M in the composition formula (1) of the basic component mentioned above, the number of atoms of these is shown in these columns, and the number of these atoms is shown in the total column. The total value (X value) is shown.

Ca and Sr in the column 2 indicate the content of the basic component composition formula (1), these columns indicate the number of atoms, and the total column indicates the total value ( Z value) is shown.

The amount of the additive component added is shown in parts by weight based on 100 parts by weight of the basic component. In the MO content column of the additive component, Ba
d, the proportion of MgO, ZnO, SrO and CaO is mol%
It is shown in

In Table 2, the temperature characteristics of capacitance are as follows: Δ(,,,(%)) and ΔC1°(%) So, 20℃
The capacitance change rates at −25° C. and +85° C. based on the capacitance of are shown as ΔC−x−(%) and ΔC0(%).

Table 2 (1) *Sealed t'R4 ma 廿 剿剉线Table 2 (2) *Marked but 7 monkeys vomited example Table 2 (3) *Marked μ7 Table 2 (4) of Seven Cursed Bites *Samples marked with a mark are Table 2 (5) of Comparative Examples *Nirito with a swipe is from Table 2 (6) of the old 1 case column *51b@ As is clear from Tables 1 and 2, according to the samples according to the present invention, when fired at 1200°C or less in a non-oxidizing atmosphere, The relative dielectric constant ε8 is 3000 or more, the dielectric loss tan δ is 2.5% or less, and the resistivity ρ is lX10'MΩ・
cm or more, temperature change rate of capacitance Δc-156 and ΔC
1□ is within the range of -15% to +15%, the temperature change rate of capacitance ΔC-! l+ and ΔC115 -10% to +10
It is possible to obtain ceramic capacitors with electrical properties within the range of

On the other hand, No, 11-16, 42, 47, 48°53.5
9,62,65,68,71,74゜77.78,82
．． 83,87,88.98°104~106,112,
According to samples 113, 117°, 118, 122, 127 and 139, it is not possible to obtain a ceramic capacitor with the desired electrical properties, and therefore these samples are outside the scope of the present invention.

In addition, Table 2 shows the temperature change rate of capacitance ΔC-5st
Although only ΔC11Sv ΔC15, ΔCas is shown, the temperature change rate ΔC of various capacitances in the range of 25°C to +85°C of the samples belonging to the scope of the present invention is -10% to +85°C.
Within the range of +10%, and -55℃ to +125℃
The rate of temperature change ΔC for various capacitances in the range -15%
It falls within the range of ~+15%.

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.

If the value of
11B is outside the range of -15% to +15%, but x+
The value of z is k, 0.0 as shown in sample Nos. 89 to 92.
In case 1, a dielectric ceramic composition having desired electrical properties can be obtained. Therefore, the lower limit of the value of X+Z is 0501.

On the other hand, the value of X+Z is sample No. -98°104.105
and 112, in the case of 50°12, △Ca
S is out of range.

When the value of X+Z is k of 0.10 as shown in sample Nos. 102, 107, 108 and 111, a dielectric ceramic composition having desired electrical properties can be obtained.

However, the value of X+Z is k, 0 as shown in sample No. 106.
．． Even if Z is 0.06, if the value of Z exceeds 0.05, a dielectric ceramic composition having desired electrical characteristics cannot be obtained.

Therefore, the upper limit of X+Z is 0.10, but at the same time Z
The upper limit of must be 0.05.

In addition, Mg and Zn of the M component and Ca and Sr of the L component work in the same way as A, and Mg
and Zn, or use one or both of Zn and 0<
One or both of Ca and Sr can be used within a range that satisfies z≦0.05. Then, M component and L
It is desirable that the value of X+Z be in the range of 0.01 to 0.10, regardless of whether one component or several components are used.

The value of y is sample No. 59.62, 65°68, 71.
As shown in samples No. 74 and 77, a dense sintered body cannot be obtained when k is 0.06, but when the value of y is
As shown in 58.61°64.67.70.73 and 76, when k is 0.04, a dielectric ceramic composition having desired electrical properties can be obtained. Therefore, the upper limit of y is 0.04.

Note that the R components Sc, Y, Dy, Ha, and Er.

Yb works in the same way as f, and the same result can be obtained even if one selected from them or a plurality of them are used. Regardless of whether there is one type of R component or multiple types of R components, it is desirable to keep the value of y in the range of 0.04 or less, and if y is 0.04 or less, it is close to 0. Even a small amount has a certain effect.

In the composition formula, the component represented by R contributes to improving the temperature characteristics of capacitance. That is, by adding the R component, the temperature
Temperature change rate of capacitance Δc-Its in the range of 25°C
It becomes possible to easily keep ΔC1□ in the range of -15% to +15%, and the temperature change rate of capacitance ΔC-1s to ΔC86 in the range of -25°C to 85°C can be reduced to -10%. ~
It becomes possible to easily keep the capacitance within the range of +10%, and it is possible to reduce the fluctuation range of the temperature change rate of capacitance in each temperature range.

Further, the R component has the effect of increasing the resistivity ρ and the effect of increasing the sinterability.

When the value of α is k, zero as shown in sample No. 78.83, the temperature change rate of capacitance ΔC-1s is -10%~
ΔC-5 is outside the range of +10% and ΔC-5 is outside the range of -15% to +15%, but if the value of α is k, 0.005 as shown in sample No. 79.84, the desired value is A dielectric ceramic composition having electrical properties can be obtained. Therefore,
The lower limit value of α is 0.005.

On the other hand, the value of α is 82. As shown in '87
, 0.05, the temperature change rate ΔC□ of capacitance is outside the range of -10% to +10%, but the value of α is k, 0.05 as shown in sample No. 81.86. In the case of 04,
A dielectric ceramic composition having desired electrical properties can be obtained. Therefore, the upper limit of a is 0.04.

The value of k is k,1 as shown in sample No. 113, 118.
．． When the resistivity ρ is less than 0, the resistivity ρ is 1. X 10
' Although it is significantly lower than MΩ·cm, when k is 1.00 as shown in sample No. 114, 119, a dielectric ceramic composition having desired electrical properties can be obtained. I can do it.

Therefore, the lower limit value of k is 1.00.

On the other hand, when the value of k is larger than 1.05 as shown in sample Nos. 117 and 122.

Although a dense sintered body cannot be obtained, the value of k is
As shown in No. 16,121, when k is 1.05, a dielectric ceramic composition having desired electrical characteristics can be obtained. Therefore, the upper limit of k is 1.05.

When the amount of additive components added is zero, sample No. 42, 4
As shown in Fig. 8, a dense sintered body cannot be obtained even if the firing temperature is 1250°C, but when the amount added is 0.2 parts by weight to 100 parts by weight of the basic components, sample No. , 43
．． As shown in 49, a sintered body having desired electrical properties can be obtained by firing at 80-1190°C. Therefore, the lower limit of the additive component is 0.2 part by weight.

On the other hand, as shown in sample No. 47.53.

When the amount of the additive component is 7.0 parts by weight, the dielectric constant ε1 is less than 3000, and ΔCss is 115% to
Although it is outside the range of +15%, when k is added in an amount of 5.0 parts by weight as shown in sample No. 46.52, a sintered body having desired electrical properties can be obtained. Therefore, the upper limit of the amount of additive components added is 5.0 parts by weight.

The preferred composition of the additive components is as shown in FIG.
It can be determined based on a triangular diagram showing the composition ratio of iOzMO.

The first point A of the triangular diagram indicates the composition of sample No. 1 with L iz O of 1 mol %, SiO2 of 80 mol %, and MO of 19 mol %, and the second point B indicates the composition of L iz O of sample No. i z
It shows a composition of 1 mol% O, 39 mol% SiO2, and 60 mol% MO, and the third point C is L of sample No-3.
i z O is 30 mol%, SiO□ is 30 mol%, MO
shows a composition of 40 mol%, and the fourth spot is sample N014.
The sample No. 5 has a composition of 50 mol% of Lit O, 50 mol% of S i Oz, and 0 mol% of MO.
mol %, MO shows a composition of 0 mol %.

The composition of the additive components of the sample that falls within the scope of the present invention is within the area surrounded by five straight lines connecting points 1 to 5 in this order in the triangular diagram shown in Figure 2. . If the composition is within this range, desired electrical characteristics can be obtained.

On the other hand, if the composition of the additive components is outside the range specified in the present invention, dense sintered bodies cannot be obtained as shown in Sample Nos. 11 to 16.

In addition, MO acid components such as k, B a O, M g O, and Z n O as shown in sample Nos. 17 to 21.

It may be either one of SrO or CaO, or it may be in an appropriate ratio as shown in other samples.

[Effect of the Invention J According to the present invention, since the composition of the dielectric ceramic composition is as described above, the dielectric constant is 3000 or more and the dielectric loss t is
anδ is 2.5% or less, resistivity ρ is lX10'MΩ・c
m or more, and the temperature change rate of the relative permittivity is -55°C
-15% to +15% at ~125℃ (based on 25℃), -
-io% to +10% at 25℃ to 85℃ (based on 20℃)
It is possible to provide a ceramic capacitor with a dielectric ceramic composition falling within the range of .

Further, according to the present invention, in a non-oxidizing atmosphere, 12
Since it can be obtained by firing at a temperature of 00°C or less, it is possible to manufacture a ceramic capacitor by applying a conductive paste of a base metal such as nickel to a green sheet and firing the green sheet and the conductive paste at the same time. can.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a multilayer ceramic capacitor according to an embodiment of the present invention, and FIG. 2 is a triangular diagram showing the composition range of additive components. 12--Porcelain layer, 14--Internal electrode, 16--External electrode.

Claims (1)

[Claims] 1. A ceramic capacitor comprising a dielectric ceramic layer made of a dielectric ceramic composition and at least two or more internal electrodes sandwiching the dielectric ceramic layer, wherein the dielectric ceramic composition contains 100 parts by weight of the basic ingredients and
It is made by firing a mixture with 0.2 to 5 parts by weight of additive components, and the basic component is (1-α) {(Ba_k_-_x_-_zM_xL_z
)O_k(Ti_1_-_yR_y)O_2_-_y_
/_2 (However, M is Mg and/or Zn, L is Ca and/or Sr, R is Sc, Y, Gd, Dy, Ho, Er,
One or more metals selected from Yb, Tb, Tm, Lu, α, k, x, z, y are 0.005≦α≦0.04 1.00≦k≦1.05 0<x<0.100<z≦0.05 0.01≦x+z≦0.10 0<y≦0.04 However, MO is B
one or more metal oxides selected from aO, SrO, CaO, MgO, and ZnO), and the composition range of the Li_2O, the SiO_2, and the MO is expressed in mol%. In the triangular diagram, a first point A indicates a composition of 1 mol% of the Li_2O, 80 mol% of the SiO_2, and 19 mol% of the MO; A second point B having a composition of 60 mol% MO; a third point C having a composition of 30 mol% Li_2O, 30 mol% SiO_2, and 40 mol% MO; a fourth point D showing a composition of 50 mol%, the SiO_2 is 50 mol%, and the MO is 0 mol%; and a composition is 20 mol% of the Li_2O, 80 mol% of the SiO_2, and 0 mol% of the MO. A ceramic capacitor characterized in that the capacitor is located within an area surrounded by five straight lines connecting in this order to a fifth point E indicating the following. 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 a lamination in which the unsintered porcelain sheet is sandwiched between at least two or more conductive paste films. forming a product, firing the laminate in a non-oxidizing atmosphere, and heat-treating the fired laminate in an oxidizing atmosphere, from the unsintered porcelain powder. The mixture consists of 100 parts by weight of the basic component and 0.2 to 5 parts by weight of additional components, and the basic component is (1-α) {(Ba_k_-_x-_zM_xL_z)
O_k(Ti_1_-_yR_y)O_2_-_y_/
_2}+αBaZrO_3 (However, M is Mg and/or Zn, L is Ca and/or Sr, R is Sc, Y, Gd, Dy, Ho, Er, Yb,
One or more metals selected from Tb, Tm, and Lu, α, k, x, z, and y are 0.005≦α≦0.04 1.00≦k≦1.05 0<x< The additive components are Li_2O, SiO_2, and MO (however, MO is B
one or more metal oxides selected from aO, SrO, CaO, MgO, and ZnO), and the composition range of the Li_2O, the SiO_2, and the MO is expressed in mol%. In the triangular diagram, a first point A indicates a composition of 1 mol% of the Li_2O, 80 mol% of the SiO_2, and 19 mol% of the MO; A second point B having a composition of 60 mol% MO; a third point C having a composition of 30 mol% Li_2O, 30 mol% SiO_2, and 40 mol% MO; a fourth point D showing a composition of 50 mol%, the SiO_2 is 50 mol%, and the MO is 0 mol%; and a composition is 20 mol% of the Li_2O, 80 mol% of the SiO_2, and 0 mol% of the MO. A method for manufacturing a ceramic capacitor, characterized in that the capacitor is located within an area surrounded by five straight lines connecting in this order a fifth point E indicating