JPH04359812A - Ceramic capacitor and its manufacture - Google Patents

Abstract

PURPOSE:To provide a ceramic capacitor having a dielectric layer of a dielectric ceramic composition which is obtained by sintering at <=1200 deg.C in a non- oxidative atmoshpere and has dielectric constant epsilon>=7000, tandelta <=2.5, and resistivity rho at least 1X10<6>MOMEGA.cm and give its manufacturing method. CONSTITUTION:A composition, is provided, consisting of mainly a basic component {(Ba1-w-xCawMgx)O}k(Ti1-y-zZryRz)O2-z/2 and containing an additive component B2O3-SiO2-Li2O2 in a ratio of 0.2-5 pts.wt. to 100 pts.wt. of the main component is used as a dielectric layer.

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 between at least two internal electrodes, and a method for manufacturing the same.

0002

[Prior Art] Conventionally, when manufacturing multilayer ceramic capacitors, unsintered porcelain sheets (
A conductive paste containing noble metals such as platinum or palladium as a main component is printed on a green sheet in a desired pattern, and a plurality of unsintered porcelain sheets are stacked and pressed together and heated at 1300°C to 1600°C in an oxidizing atmosphere. It was fired. By this firing, the unsintered ceramic sheet becomes a dielectric ceramic layer, and the conductive paste becomes an internal electrode.

[0003] As described above, if a conductive paste containing a noble metal such as platinum or palladium as a main component is used, the conductive paste can be heated to 1,300°C to 1,300°C in an oxidizing atmosphere.
Even if the conductive paste is fired at a high temperature of 600° C., the intended internal electrode can be obtained without oxidizing the conductive paste. However, since noble metals such as platinum and palladium are expensive, manufacturing such multilayer ceramic capacitors inevitably leads to high costs.

[0004] Therefore, in order to solve the above-mentioned problem, the present applicant has proposed Japanese Patent Publication No. 60-20851, Japanese Patent Application Laid-open No. 147404-1982, and Japanese Patent Application Laid-Open No. 61-1989.
The inventions disclosed in Japanese Patent Application Laid-open No. 147405 and Japanese Patent Application Laid-Open No. 147406/1983 were proposed.

[0005] Here, in Japanese Patent Publication No. 60-20851, {(Bax Cay Srz )O}k (T
A basic component consisting of in Zr1-n)O2 and Li
2 O, SiO2 and MO (however, MO is BaO, Ca
A dielectric ceramic composition containing an additive component consisting of one or more oxides selected from O and SrO is disclosed.

[0006] Furthermore, in Japanese Patent Application Laid-open No. 147404/1983, {(Ba1-x-y Cax Sry)O}
A dielectric ceramic composition is disclosed that includes a basic component consisting of k(Ti1-zZrz)O2 and additional components consisting of B2O3, SiO2, and Li2O.

[0007] Furthermore, in Japanese Patent Application Laid-Open No. 147405/1986, {(Ba1-x-y Cax Sry)O}
A dielectric ceramic composition is disclosed that includes a basic component consisting of k (Ti1-z Zrz )O2 and additional components consisting of B2 O3 and SiO2.

[0008] Furthermore, in Japanese Patent Application Laid-Open No. 147406/1986, {(Ba1-x-y Cax Sry)O}
A basic component consisting of k(Ti1-z Zrz)O2, B2O3, SiO2, and MO (however, MO is B
A dielectric ceramic composition containing an additive component consisting of one or more oxides selected from aO, CaO, and SrO is disclosed.

The dielectric ceramic compositions disclosed in these publications have a relative dielectric constant ε of 5000 or more and a resistivity ρ of 1×
106 MΩ・cm or more, and if these dielectric ceramic compositions are used as a dielectric layer, a conductive paste containing a base metal such as Ni as the main component is used as the material for the internal electrode, and the Ceramic capacitors with excellent electrical characteristics can be obtained at low cost by firing at a temperature of 0.degree. C. or lower.

0010

[Problem to be Solved by the Invention] In recent years, with the increasing density of electronic circuits, there has been a strong demand for smaller ceramic capacitors, especially multilayer ceramic capacitors.
The dielectric constant ε of the dielectric ceramic composition constituting the dielectric layer of the multilayer ceramic capacitor can be adjusted to the dielectric constant ε of the dielectric ceramic composition disclosed in the above publications without deteriorating other electrical properties. It was desired to further increase ε.

Therefore, an object of the present invention is to reduce the ratio of the dielectric ceramic composition constituting the dielectric layer, although it can be obtained by firing at a temperature of 1200° C. or lower in a non-oxidizing atmosphere. Dielectric constant ε is 7000 or more, dielectric loss t
anδ is 2.5% or less, resistivity ρ is 1×106 MΩ・
The object of the present invention is to provide a ceramic capacitor whose electrical characteristics are even better than those of conventional capacitors, and a method for manufacturing the same.

0012

[Means for Solving the Problems] A ceramic capacitor according to the present invention includes one or more dielectric ceramic layers made of a dielectric ceramic composition, and at least two or more internal layers sandwiching the dielectric ceramic layers. The dielectric ceramic composition is made of a fired mixture of 100.0 parts by weight of a basic component and 0.2 to 5.0 parts by weight of an additive component, and The basic component is {(Ba1-w
-x Caw Mgx )O}k (Ti1-y-z
Zry Rz )O2-z/2 (However, R is Sc,
Y, Gd, Dy, Ho, Er, Yb, Tb, Tm and L
One or more elements selected from u, w, x,
y, z, k are: 0.00≦w≦0.27 0.001≦x≦0.03 0.05≦y≦0.26 0.002≦z≦0.04 1.00≦k≦1 .04), the additive components are B2 O3, SiO2, and Li2 O, and the B2 O3, SiO2, and Li2
In the triangular diagram showing these compositions in mol %, the composition range with O is 1 mol % for the B2 O3 and 1 mol % for the SiO2
A first point A having a composition of 50 mol% of B2 O, 49 mol% of Li2O, 50 mol% of B2O3, 1 mol% of SiO2, and 49 mol% of Li2O.
A second point B showing the composition of
A third point C having a composition of 9 mol% and the B2O3
is 89 mol%, the SiO2 is 10 mol%, and the Li
A fourth point D showing a composition of 1 mol% 2O, and the above B2
A fifth point E has a composition of 19 mol% O3, 80 mol% SiO2, and 1 mol% Li2O, and 1 mol% B2O3, 80 mol% SiO2, and 1 mol% Li2O. It is located within a region surrounded by six straight lines connecting in this order to the sixth point F showing a composition of 19 mol %.

Here, Ca in the compositional formula of the basic component
The ratio of the number of atoms, that is, the range of the value of w, is 0.00≦w
The reason for setting ≦0.27 is that when the value of w is within this range,
It has the desired electrical characteristics, flat temperature characteristics, and resistivity ρ.
Although it is possible to obtain a dielectric ceramic composition with a high value of w, if the value of w exceeds 0.27, the firing temperature will be as high as 1250° C. and the dielectric constant εs will also be less than 7000.

[0014] As mentioned above, this Ca is an element added to flatten the temperature characteristics of the ceramic capacitor and to improve the resistivity ρ, so even if it is not intentionally included, the value of w It is possible to obtain a sintered body having desired electrical properties even when the value is zero. Therefore, the case of zero was included as the lower limit of the value of w.

Next, the ratio of the number of Mg atoms in the composition formula of the basic component, that is, the range of the value of x, is set to 0.001≦x
The reason for setting ≦0.03 is that when the value of x is within this range, a dielectric ceramic composition having the desired electrical properties can be obtained, but when the value of x exceeds 0.03, The dielectric constant εs of the dielectric ceramic composition suddenly decreased to 7000.
This is because it is less than

[0016] Although Mg has the effect of shifting the Curie point to the lower temperature side, flattening the temperature characteristics, and improving the resistivity ρ, Mg is present in extremely small amounts in the range where the value of x is 0.03 or less. Even if there is, it has some effect. However, in consideration of variations in electrical characteristics during mass production, it is desirable that the value of x be 0.001 or more.

Next, the ratio of the number of Zr atoms in the compositional formula of the basic component, that is, the range of the value of y, is set to 0.05≦y≦
The reason for setting 0.26 is that when the value of y is within this range, a dielectric ceramic composition having desired electrical properties can be obtained, but when the value of y is less than 0.05 and 0.26 is If the dielectric constant εs of the dielectric ceramic composition exceeds 7000
This is because it is less than

[0018] Furthermore, the ratio of the number of atoms of R in the composition formula of the basic component, that is, the range of the value of z, is set to 0.002≦z≦
The reason why the value of z is set to 0.04 is that when the value of z is within this range, a dielectric ceramic composition having the desired electrical properties can be obtained, but when the value of z is less than 0.002, the dielectric ceramic composition can be obtained. The dielectric loss tan δ of the material deteriorates significantly, and the resistivity ρ also decreases to 1×
This is because if it is less than 104 MΩ·cm and exceeds 0.04, a dense sintered body cannot be obtained even if the firing temperature is 1250°C.

[0019] Note that the R components Sc, Y, Gd, Dy, H
o, Er, Yb, Tb, Tm and Lu work in almost the same way, and the same result can be obtained even if one selected from them or a plurality of them are used. Also, among the R components in the basic component composition formula, Tb, Tm and Lu
are not listed in Table 3 below, but these are also included in other R
It has the same effects as the ingredients.

{(Ba1-
w−x Caw Mgx )O}, that is, the range of the value of k is set to 1.00≦k≦1.04, because when the value of k is within this range, the dielectric has the desired electrical characteristics. However, if the resistivity ρ of the dielectric ceramic composition is less than 1.00, the resistivity ρ of the dielectric ceramic composition is 1×106.
If the tan δ becomes significantly lower than MΩ・cm and exceeds 1.04, the firing temperature should be set to 1250
This is because a dense sintered body cannot be obtained even at ℃.

[0021] The basic components may contain a trace amount of MnO2 (preferably 0.0
A mineralizing agent such as 5% to 0.1% by weight) may be added to improve sinterability. Further, other substances may be added as necessary. Further, as a starting material for obtaining the basic component, oxides other than those shown in the examples described below, hydroxides, or other compounds may be used.

[0022] Next, the addition amount of the additive component was set to 0.2 to 5.0 parts by weight based on 100 parts by weight of the basic component.
If the amount of the additive component is within this range, 1190 to 12
A sintered body with the desired electrical properties can be obtained by firing at 00°C, but if the amount of additive components is less than 0.2 parts by weight, it will not be dense even if the firing temperature is 1250°C. It is not possible to obtain a sintered body, and if the amount of additive components exceeds 5.0 parts by weight, the dielectric constant εs will be 70.
This is because it becomes less than 00.

[0023] The composition of the additive components is B2 O3 and SiO
In the triangular diagram showing the composition of Li2O and Li2O in mol%, the reason why the above-mentioned points A to F are placed within the range surrounded by six straight lines connecting them in this order is because if the composition of the added component is within this range. Although it is possible to obtain a sintered body having desired electrical properties, if the composition of the added components is outside this range, a dense sintered body cannot be obtained.

Next, the method for manufacturing a ceramic 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 preparing an unsintered porcelain powder of the above-mentioned mixture. a step of forming a sheet, 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 fired laminate in an oxidizing atmosphere.

Here, the non-oxidizing atmosphere is H2
In addition to a reducing atmosphere such as or CO, a neutral atmosphere such as N2 or Ar may be used. Furthermore, the firing temperature in the non-oxidizing atmosphere can be varied in consideration of the electrode material. When using nickel as the internal electrode,
Heat treatment can be performed in the range of 1050°C to 1200°C without causing almost any aggregation of the nickel particles.

The temperature of the heat treatment in an oxidizing atmosphere may be lower than the firing temperature in a non-oxidizing atmosphere, and is preferably in the range of 500 to 1000°C. The oxidizing atmosphere is not limited to the atmospheric atmosphere, and any atmosphere with any oxygen concentration can be used, from a low oxygen concentration atmosphere such as a mixture of several ppm of O2 to N2, for example. The temperature and oxygen concentration of the atmosphere depends on the electrode material (nickel, etc.)
It is necessary to make various changes in consideration of the oxidation of the dielectric ceramic layer and the oxidation of the dielectric ceramic layer. In the examples described later, the temperature of this heat treatment was set to 6.
Although the temperature was set at 00°C, the temperature is not limited to this.

In addition, in the examples, heat treatment in a non-oxidizing atmosphere and heat treatment in an oxidizing atmosphere are performed in one continuous firing profile, but of course the firing process in a non-oxidizing atmosphere and the heat treatment in an oxidizing atmosphere are It is also possible to carry out the heat treatment step in a neutral atmosphere as separate steps.

Furthermore, although a Zn electrode is used as the external electrode in the embodiment, it is of course possible to use an electrode made of Ni, Ag, Cu, etc. by selecting the baking conditions for the electrode. It is also possible to apply the external electrode to the end face of the unfired laminate and to simultaneously perform the firing of the laminate and the external electrode.

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

[0030]

[Example] First, sample No. 3 in Table 3. Case 1 will be explained. Preparation of Basic Components The compounds shown in Table 1 were each weighed, and these compounds were placed in a pot mill along with a plurality of alumina balls and 2.5 liters of water, and mixed with stirring for 15 hours to obtain a mixture.

[0031]

[Table 1]

Here, the weight (g) of each compound in Table 1 is:
Compositional formula of the basic component {(Ba1-w-x Caw M
gx )O}k (Ti1-y-z Zry Rz)
O2-z/2 is {(Ba0.925Ca0.0
7Mg0.005)O}1.01(Ti0.83Zr0
．． 15Er0.02)O1.99 (1) This is the value calculated as follows.

Next, the mixture was placed in a stainless steel pot and dried at 150° C. for 4 hours using a hot air dryer, and the dried mixture was coarsely ground. The powder was calcined for 2 hours at about 1200° C. to obtain a powder having the basic components represented by the above compositional formula (1).

Preparation of additive components Also, weigh each of the compounds shown in Table 2, add these compounds to a polyethylene pot together with a plurality of alumina balls and 300 ml of alcohol, and stir and mix for 10 hours to obtain a mixture. Ta.

[0035]

[Table 2]

Here, the weight (g) of each compound in Table 2 is:
B2 O3 is 1 mol%, SiO2 is 50 mol%, L
This value was calculated so that the i2O content was 49 mol%.

Next, the mixture was placed in the atmosphere for about 10 minutes.
This was calcined at a temperature of 00°C for 2 hours, put into an alumina pot together with several alumina balls and 300ml of water, pulverized for 15 hours, and then dried at 150°C for 4 hours to remove the additive components of the above composition. A powder was obtained.

Preparation of slurry Next, 100 parts by weight (1000 g) of the above basic ingredients;
Put 2 parts by weight (20 g) of the above additive components into a ball mill, and further add 15% by weight of an organic binder and 50% by weight of water based on the total weight of these basic components and additive components, and mix these. and pulverized to obtain a slurry that would serve as a raw material for a dielectric ceramic composition. Here, the organic binder used was an aqueous solution of an acrylic ester polymer, glycerin, and condensed phosphate.

Formation of unsintered porcelain sheet Next, the above slurry was put into a vacuum defoaming machine and degassed.
This defoamed slurry is applied onto a polyester film to a predetermined thickness using a reverse coater, and this applied slurry is coated with this polyester film in one coat.
It was dried by heating at 00° C. to obtain a long unsintered porcelain sheet with 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 with 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 and stirred for 10 hours. , a conductive paste for internal electrodes was obtained. A pattern (length 1
4 mm in width and 7 mm in width) were formed by screen printing and dried.

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

Pressing and cutting of the laminate Next, at a temperature of about 50° C., a load of about 40 tons was applied from the thickness direction to the unsintered porcelain sheet constituting the laminate. They were pressed together. Then, this laminate was cut into a grid shape to obtain 50 laminate chips.

Firing of the laminate chip Next, the laminate chip was placed in a furnace capable of firing in an atmosphere, the inside of the furnace was made into an atmospheric atmosphere, and the laminate chip was heated at a rate of 100°C/h for 6 hours.
The temperature was raised to 00°C to burn off the organic binder in the unsintered porcelain sheet.

After that, the atmosphere inside the furnace was changed from the atmospheric atmosphere to a reducing atmosphere {H2 (2 volume %) + N2 (98 volume %)}, and the temperature inside the furnace was increased from 600°C to 1130°C for 10 minutes.
The temperature was raised at a rate of 0°C/h, maintained at a temperature of 1130°C for 3 hours, and then lowered at a rate of 100°C/h to change the atmosphere inside the furnace to an atmospheric atmosphere (oxidizing atmosphere).
The oxidation treatment was carried out by maintaining the temperature of ℃ for 30 minutes, and then
The laminated sintered body chips were obtained by cooling to room temperature.

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

Here, the external electrode 16 is formed by applying a conductive paste consisting of zinc, glass frit, and vehicle to the side surface, and drying the conductive paste for 5 minutes in the atmosphere.
A zinc electrode layer 18 is formed by baking at a temperature of 50° C. for 15 minutes, a copper layer 20 is formed on this zinc electrode layer 18 by electroless plating, and Pb- is further formed on this copper layer 20 by electroplating. It was formed by providing a Sn solder layer 22.

Note that the thickness of the dielectric ceramic layer 12 of this multilayer ceramic capacitor 10 is 0.02 mm, and the
The opposing area of 4 and 14 is 5 mm x 5 mm = 25 mm2. Further, the composition of the dielectric ceramic layer 12 after sintering is substantially the same as the composition of the mixture of basic components and additive components before sintering.

Measurement of Electrical Characteristics Next, the electrical characteristics of the multilayer ceramic capacitor 10 were measured.
When the average values were determined, as shown in Table 4, the dielectric constant εs was 15,200, the tan δ was 1.4%, and the resistivity ρ was 3.28×10 6 MΩ·cm.

[0049] The electrical characteristics were measured in the following manner. (A) The relative permittivity εs is at a temperature of 20°C and a frequency of 1kHz.
z, the capacitance was measured under the conditions of voltage (effective value) 1.0V, and this measured value, the opposing area (25 mm2) of the pair of internal electrodes 14, 14, and the dielectric between the pair of internal electrodes 14, 14. It was calculated from the thickness of the ceramic layer 12 (0.02 mm). (B) The dielectric loss tan δ (%) was measured under the same conditions as in the measurement of the dielectric constant εs described above. (C) Resistivity ρ (MΩ cm) is calculated based on the measured value and dimensions by measuring the resistance value between the pair of external electrodes 16, 16 after applying DC 100 V for 1 minute at a temperature of 20 ° C. I asked for it.

[0050] Above, No. As mentioned about sample 1,
No. Regarding samples 2 to 92, the compositions of the basic components were changed as shown in Tables 3■ to 3■, and the compositions of additional components and firing temperatures were changed as shown in Tables 4■ to 4■. No
．． A multilayer ceramic capacitor was prepared in exactly the same manner as Sample 1, and its electrical characteristics were measured in the same manner. No. 1~
The firing temperature and electrical characteristics of 92 samples are shown in Tables 4■ to 4■
The result was as shown in .

[0051]

[Table 3■]

[0052]

[Table 3 ■]

[0053]

[Table 3 ■]

[0054]

[Table 3■]

[0055]

[Table 3■]

[0056]

[Table 3 ■]

[0057]

[Table 4 ■]

[0058]

[Table 4 ■]

[0059]

[Table 4 ■]

[0060] In Tables 3■ to 3■, the column 1-w-x indicates the ratio of the number of Ba atoms in the composition formula of the basic component.
The w column shows the ratio of the number of Ca atoms in the composition formula of the basic component, the x column shows the ratio of the number of Mg atoms in the basic component composition formula, and the 1-y-z column shows the ratio of the number of Mg atoms in the basic component composition formula. The ratio of the number of Ti atoms in the compositional formula is shown, and the y column shows the ratio of the number of Zr atoms in the compositional formula of the basic component.

[0061] Also, the z column shows the ratio of the number of atoms of R in the basic component composition formula, and the k column shows the ratio of {(Ba1-w-x Caw Mgx)O} in the basic component composition formula. It is shown. Sc, Y, Gd, Dy in the z column,
Ho, Er, Yb indicate the content of R in the composition formula of the basic component, each column for these elements shows the ratio of the number of atoms of these elements, and the total column shows the percentage of the number of atoms of these elements. The total value (z value) of the ratio of the number of atoms is shown.

[0062] In Tables 4 (1) to 4 (4), the amounts of additional components added are shown in parts by weight relative to 100 parts by weight of the basic components.

[0063] Also, No. Experiments using samples No. 1 to No. 15 clarified the appropriate range of glass as an additive component.
Experiments using samples Nos. 16 to 27 clarified the appropriate range of the amount of glass added, and No. Experiments using samples No. 28 to 39 clarified the appropriate range of the w value, which is the ratio of the number of Ca atoms. Experiments using samples No. 40 to No. 51 clarified the appropriate range of the x value, which is the ratio of the number of Mg atoms. Experiments using samples No. 52 to 61 clarified the appropriate range of the y value, which is the ratio of the number of Zr atoms. 62～
Experiments using 70 samples revealed the effects of different types of R, and No. Experiments using samples No. 71 to 82 clarified the appropriate range of the z value, which is the ratio of the number of R atoms.
The experiments with samples 83 to 92 were conducted with {(Ba1-w-x C
The purpose is to clarify the appropriate range of the k value, which is the ratio of aw Mgx )O}.

As is clear from Tables 3■ to 3■ and Tables 4■ to 4■, according to the samples according to the present invention, when fired at 1200°C or less in a non-oxidizing atmosphere, the dielectric constant εs
7000 or more, dielectric loss tan δ is 2.5% or less, and resistivity ρ is 1×10 MΩ·cm or more. .

On the other hand, No. 12-16, 21, 2
2, 27, 33, 39, 45, 51, 52, 56, 57
, 61, 71, 76, 77, 82, 83, 87, 88 and 92, it was not possible to obtain a ceramic capacitor having the desired electrical characteristics. Therefore, these N
o. These samples are outside the scope of the present invention.

Next, regarding the appropriate range of the composition of the dielectric ceramic composition used in the ceramic capacitor according to the present invention, refer to the experimental results shown in Tables 3■ to 3■ and Tables 4■ to 4■. I will consider it while doing so.

First, the ratio of the number of Ca atoms in the composition formula of the basic components, that is, the appropriate range of the value of w will be discussed. The value of w is sample no. As shown in Sample Nos. 32 and 38, in the case of 0.27, a dielectric ceramic composition sintered body having desired electrical characteristics can be obtained.
33 and 39, in the case of 0.30, the firing temperature is as high as 1250°C, and the dielectric constant εs is also 700°C.
It becomes less than 0. Therefore, the upper limit value of w is 0.27.

Further, although Ca has the effect of flattening the temperature characteristics and improving the resistivity ρ, it is not possible to obtain a dielectric ceramic composition with desired electrical characteristics even if the value of w is zero. can. Therefore, the lower limit value of w is zero.

Next, the ratio of the number of Mg atoms in the composition formula of the basic component, ie, the appropriate range of the value of x, will be discussed. The value of x is sample No. As shown in Sample Nos. 44 and 50, when the value is 0.03, a dielectric ceramic composition having desired electrical characteristics can be obtained. 45 and 51, in the case of 0.04, the dielectric constant εs
rapidly decreases to less than 7,000. Therefore, the upper limit of x is 0.03.

[0070] Furthermore, Mg has the effect of shifting the Curie point to the lower temperature side, flattening the temperature characteristics, and improving the resistivity ρ; Even if there is, it has some effect. However, in consideration of variations in electrical characteristics during mass production, it is desirable that the value of x be 0.001 or more.

Next, the ratio of the number of Zr atoms in the compositional formula of the basic components, that is, the appropriate range of the value of y, will be discussed. The value of y is the sample No. As shown in Sample Nos. 53 and 58, in the case of 0.05, a dielectric ceramic composition having desired electrical characteristics can be obtained; 52 and 57, in the case of 0.03, the dielectric constant ε
s becomes less than 7000. Therefore, the lower limit of the value of y is 0
．． It is 05.

On the other hand, the value of y is different from sample No. 55 and 60
As shown in Sample No. 0.26, a dielectric ceramic composition with desired electrical characteristics can be obtained. 5
6 and 61, in the case of 0.29, the dielectric constant εs becomes less than 7000. Therefore, the upper limit of the value of y is 0.26.

Next, the ratio of the number of R atoms in the composition formula of the basic component, ie, the appropriate range of the value of z, will be discussed. The value of z is the sample no. As shown in 72 and 78,
In the case of sample No. 0.002, a dielectric ceramic composition having desired electrical properties can be obtained. As shown in 71 and 77, in the case of 0.001, the dielectric loss tan δ deteriorates significantly, and the resistivity ρ also decreases to 1 × 104 MΩ.
・Less than cm. Therefore, the lower limit of z is 0.002.

On the other hand, the value of z is different from sample No. 75 and 81
As shown in FIG.
o. As shown in 76 and 82, in the case of 0.06,
Even if the firing temperature is 1250°C, a dense sintered body cannot be obtained. Therefore, the upper limit of the value of z is 0.04.

[0075] Furthermore, the R component Sc, Y, Dy, Ho, E
r and Yb work in almost the same way, and the same result can be obtained even if one selected from them or a plurality of them are used. In addition, among the R components, Tb, Tm, and Lu are not listed in Tables 3■ to 3■, but these are also included in other R components.
It has the same effects as the ingredients.

Next, {(B
a1-w-x Caw Mgx )O}, that is, the appropriate range of the value of k will be considered. The value of k is the sample no. As shown in Sample Nos. 84 and 89, when the value is 1.00, a dielectric ceramic composition having desired electrical characteristics can be obtained; As shown in 83 and 88,
In the case of 0.99, the resistivity ρ is 1×106 MΩ・c
If it is less than m, tan δ becomes significantly lower and deteriorates. Therefore, the lower limit value of k is 1.00.

On the other hand, the value of k is different from sample No. 86 and 91
As shown in Sample No. 1.04, a dielectric ceramic composition with desired electrical characteristics can be obtained. 8
As shown in 7 and 92, when it is 1.05, a dense sintered body cannot be obtained. Therefore, the upper limit of k is 1
．． It is 04.

Next, the appropriate range of the amount of additive components to be added will be discussed. The added amount of the additive component is the same as that of sample No. 17 and 23, 0 for 100 parts by weight of the basic component.
．． In the case of 2 parts by weight, a dielectric ceramic composition having the desired electrical properties can be obtained by firing at 1190 to 1200°C, but if the amount of the additive component is zero, Sample N
o. As shown in 16 and 22, the firing temperature is 1250℃
However, it is not possible to obtain a dense sintered body. Therefore, the lower limit of the amount of additive components added is 0.2 parts by weight per 100 parts by weight of the basic components.

On the other hand, the amount of the additive component added was different from sample No. 2
As shown in 0 and 26, when the amount is 5 parts by weight relative to 100 parts by weight of the basic component, a dielectric ceramic composition having desired electrical properties can be obtained, but the addition amount of the additive component is , Sample No. As shown in 21 and 27, when the amount is 7 parts by weight relative to 100 parts by weight of the basic component, the dielectric constant εs becomes less than 7000. Therefore, the upper limit of the amount of the additive component added is 5 parts by weight per 100 parts by weight of the basic component.

Next, the preferred composition range of the additive components will be discussed. The preferred composition range of the additive components can be determined based on the triangular diagram showing the composition ratio of B2O3-SiO2-Li2O shown in FIG.

The first point A in the triangular diagram is sample No. 1 B
2 O3 is 1 mol%, SiO2 is 50 mol%, Li2
The second point B has a composition of 49 mol% O.
o. Sample No. 2 has a composition of 50 mol % B2 O3, 1 mol % SiO2, and 49 mol % Li2 O, and the third point C is sample No. 2. B2O3 of 3 is 80 mol%, Si
The fourth point D shows a composition of 1 mol% O2 and 19 mol% Li2O. 4 B2 O3 is 89
mol%, SiO2 is 10 mol%, Li2O is 1 mol%, and the fifth point E is sample No. 5 B2
O3 is 19 mol%, SiO2 is 80 mol%, Li2
O shows a composition of 1 mol %, and the sixth point F is sample No.
6 B2 O3 is 1 mol%, SiO2 is 80 mol%
, Li2O shows a composition of 19 mol%.

[0082] The added components of the sample belonging to the composition range of the present invention are within the range surrounded by six straight lines connecting points A to F of the triangular diagram shown in Fig. 2 in this order. . If the composition of the additive components is within this range, a dielectric ceramic composition having desired electrical properties can be obtained. On the other hand, sample No. If the composition of the additive components is outside the range specified in the present invention, as in Nos. 12 to 15, a dense sintered body cannot be obtained.

[0083]

According to the present invention, the composition of the dielectric ceramic composition constituting the dielectric layer of the ceramic capacitor is configured as described above.
Despite being fired at 0°C or lower, its relative dielectric constant ε
s could be dramatically improved to 7,000 to 18,800, making it possible to make ceramic capacitors smaller and larger in capacity.

[0084] Now that it has become possible to make ceramic capacitors smaller and larger in capacity, it is possible to reduce the cost of ceramic capacitors by using a conductive paste of a base metal such as nickel to form the internal electrodes. It became possible.

[Brief explanation of the drawing]

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 appropriate ranges of added components.

[Explanation of symbols]

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]

[Table 4○1]

[Table 4○2]

[Table 4○3]

Claims (2)

[Claims] 1. A ceramic capacitor comprising one or more dielectric ceramic layers made of a dielectric ceramic composition and at least two or more internal electrodes sandwiching the dielectric ceramic layers, wherein the dielectric The porcelain composition is made by firing a mixture of 100.0 parts by weight of a basic component and 0.2 to 5.0 parts by weight of an additive component, and the basic component is {(B
a1-w-x Caw Mgx )O}k (Ti1-
y-z Zry Rz )O2-z/2 (However, R is Sc, Y, Gd, Dy, Ho, Er, Yb, Tb, T
one or more elements selected from m and Lu;
w, x, y, z, k are: 0.00≦w≦0.27 0.001≦x≦0.03 0.05≦y≦0.26 0.002≦z≦0.04 1.00 ≦k≦1.04), the additive components are B2 O3, SiO2, and Li2 O, and the B2 O3, SiO2, and Li2
In the triangular diagram showing these compositions in mol %, the composition range with O is 1 mol % for the B2 O3 and 1 mol % for the SiO2
A first point A having a composition of 50 mol% of B2 O, 49 mol% of Li2O, 50 mol% of B2O3, 1 mol% of SiO2, and 49 mol% of Li2O.
A second point B showing the composition of
A third point C having a composition of 9 mol% and the B2O3
is 89 mol%, the SiO2 is 10 mol%, and the Li
A fourth point D showing a composition of 1 mol% 2O, and the above B2
A fifth point E has a composition of 19 mol% O3, 80 mol% SiO2, and 1 mol% Li2O, and 1 mol% B2O3, 80 mol% SiO2, and 1 mol% Li2O. A ceramic capacitor characterized in that the capacitor is located within a region surrounded by six straight lines connecting in this order a sixth point F having a composition of 19 mol%. 2. A step of preparing a mixture consisting of unsintered porcelain powder, a step of forming an unsintered porcelain sheet consisting of the mixture, and a step of preparing the unsintered porcelain sheet at least twice.
a step of forming a laminate sandwiched between the conductive paste films, 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 consisting of the unsintered porcelain powder contains 100.0 parts by weight of the basic component and 0.0 parts by weight of the base component;
．． 2 to 5.0 parts by weight of additional components, and the basic component is {(Ba1-w-x Caw Mgx )O}k (T
i1-y-z Zry Rz )O2-z/2 (However, R is Sc, Y, Gd, Dy, Ho, Er, Yb, T
One or more elements selected from b, Tm and Lu, w, x, y, z, k are: 0.00≦w≦0.27 0.001≦x≦0.03 0.05 ≦y≦0.26 0.002≦z≦0.04 1.00≦k≦1.04), and the additive components are B2 O3, SiO2, and Li2 O. , the B2 O3, the SiO2, and the Li2
In the triangular diagram showing these compositions in mol %, the composition range with O is 1 mol % for the B2 O3 and 1 mol % for the SiO2
A first point A having a composition of 50 mol% of B2 O, 49 mol% of Li2O, 50 mol% of B2O3, 1 mol% of SiO2, and 49 mol% of Li2O.
A second point B showing the composition of
A third point C having a composition of 9 mol% and the B2O3
is 89 mol%, the SiO2 is 10 mol%, and the Li
A fourth point D showing a composition of 1 mol% 2O, and the above B2
A fifth point E has a composition of 19 mol% O3, 80 mol% SiO2, and 1 mol% Li2O, and 1 mol% B2O3, 80 mol% SiO2, and 1 mol% Li2O. A method for producing a ceramic capacitor, characterized in that the capacitor is located within an area surrounded by six straight lines connecting in this order a sixth point F having a composition of 19 mol%.