JP2002075054A - Dielectric porcelain composition - Google Patents

Abstract

(57) [Problem] To provide a dielectric ceramic composition capable of reliably mass-producing a laminated ceramic capacitor having small characteristic variations and the like. SOLUTION: The general formula (CaO) _x (Zr _1-y .Ti _y ) O ₂
(However, 0.95 ≦ x ≦ 1.05, 0.01 ≦ y ≦ 0.
The fundamental component 100 parts by weight represented by the 10 value in the range of), and the MnCO ₃ 1 to 5 parts by weight, the formula a SiO ₂
-BLi ₂ O-cY ₂ O ₃ (however, 0.35 ≦ a ≦ 0.4
5, 0.35 ≦ b ≦ 0.45, 0.1 ≦ c ≦ 0.3) or the general formula dSiO ₂ -eB ₂ O ₃ -fY
₂ O ₃ (provided that 0.4 ≦ d ≦ 0.7, 0.15 ≦ e ≦ 0.
35, a numerical value in the range of 0.1 ≦ f ≦ 0.3) in an amount of 0.5 to 5 parts by weight.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric ceramic composition suitable as a dielectric for a laminated ceramic capacitor having a base metal such as nickel as an internal electrode.

[0002]

2. Description of the Related Art Conventionally, when manufacturing a laminated ceramic capacitor, a conductive paste of a noble metal such as platinum or palladium is printed in a desired pattern on a green sheet (unsintered ceramic sheet) made of dielectric ceramic raw material powder. A plurality of these were stacked, pressed and sintered in an oxidizing atmosphere at 1300 ° C. to 1600 ° C. Thereby, a dielectric ceramic and an internal electrode are obtained at the same time. As described above, if a noble metal is used, a target internal electrode can be obtained even when sintering at a high temperature in an oxidizing atmosphere. However, since noble metals such as platinum and palladium are expensive, the cost of the multilayer ceramic capacitor is inevitably increased.

In order to solve this kind of problem, CaZr
The use of a porcelain composition comprising O ₃ and MnO ₂ as a dielectric for a capacitor is disclosed in, for example, Japanese Patent Application Laid-Open No. 53-9809.
No. 9 discloses this. Since the dielectric ceramic composition disclosed herein can be fired in a reducing atmosphere,
Oxidation of base metals such as nickel does not occur.

Meanwhile, the above-mentioned dielectric porcelain composition comprising CaZrO ₃ and MnO ₂ has a high temperature (1350 ° C. to 138 ° C.).
(0 ° C.). For this reason, when a conductive paste containing nickel as a main component is printed on a green sheet and fired, even when firing in a non-oxidizing atmosphere, melting and aggregation of nickel particles occur, and nickel is distributed in a ball shape. I do. In addition, nickel is diffused into the dielectric porcelain due to the high temperature firing, and the dielectric porcelain is deteriorated in insulation. As a result, it has been difficult to obtain a porcelain capacitor having desired capacitance and insulation resistance.

[0005] Therefore, a non-reducing temperature-compensating dielectric porcelain composition in which a glass component (sintering aid) composed of Si-Li-alkaline earth metal is added to a basic component composed of CaZrO ₃ and CaTiO _3. The thing is S-5-52604, S
Japanese Patent Publication No. 5-52603 discloses a non-reducing temperature-compensating dielectric ceramic composition to which a glass component (sintering aid) composed of i-B-alkaline earth metal is added.

Since the dielectric ceramic composition of the present invention can be obtained by firing at 1100 to 1300 ° C. in a non-oxidizing atmosphere, it is suitable as a dielectric for a temperature-compensating laminated ceramic capacitor having a base metal such as nickel as an internal electrode. It is something.

[0007]

However, according to the above-mentioned dielectric porcelain composition, Li and B, which are low-melting elements, are remarkably evaporated. In the temperature range, Li and B begin to evaporate,
Finally, the sintering start temperature of porcelain is 1000 ° C. to 1100
When the temperature is in the vicinity of ° C., there is a problem that the glass composition has a greatly reduced amount of Li and B elements, resulting in insufficient sintering of the porcelain and large variations in characteristics. This problem is especially noticeable in the EIA standard.
This was remarkable in small-sized laminated ceramic capacitors of type 16 or less.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dielectric ceramic composition which can be stably fired even in a reducing atmosphere at 1100 ° C. to 1300 ° C. and has small characteristic variations. It is to be.

[0009]

The dielectric ceramic composition of the present invention has the general formula (CaO) _x (Zr _{1 -y} · Ti _y ) O ₂ (where 0.95 ≦ x ≦ 1.05, 0 .01 ≦ y ≦ 0.10
And MnCO _{3 in an amount} of 1 to 5 parts by weight and a glass component in an amount of 0.5 to 100 parts by weight of the basic component represented by
-5 parts by weight.

That is, if x of the basic component is less than 0.95, Q
If the value is significantly reduced and exceeds 1.05, 1100
Not sufficiently sintered at １1300 ° C. Also, if y is 0.01
If it is less than 25, the dielectric constant becomes 25 or less, and the target is not satisfied. Further, even when y exceeds 0.10, the absolute value of the temperature characteristic of the dielectric constant becomes larger than 30 ppm.

When the composition of the glass component of the present invention is represented by the general formula (1) aSiO ₂ -bLi ₂ O-cY ₂ O ₃ (where a + b + c = 1) (1) , C values in the triangular diagram of FIG. 1 are composed of compositions located inside a region connected by coordinates A, B, C, and D (including a line).

That is, if the value of a of the glass is less than 0.35, the glass cannot be sufficiently sintered. Further, when it exceeds 0.45, the Q value is significantly reduced. On the other hand, if b is less than 0.35, sintering will not be sufficient. Further, when it exceeds 0.45, the Q value is significantly reduced. Further, when c is less than 0.1, the capacitance value variation (CV
Value) is greater than 0.3 and 1100 to 13
Does not sinter sufficiently at 00 ° C.

Alternatively, when the composition of the glass component of the present invention is represented by the general formula (2) dSiO ₂ -eB ₂ O ₃ -fY ₂ O ₃ (where d + e + f = 1), In the triangular diagram of FIG. 2, the e and f values are composed of compositions located inside a region connected by coordinates E, F, G, H, I, and J (including a line).

That is, if d of the glass is less than 0.4, the glass is not sufficiently sintered. Further, when it exceeds 0.70, the Q value is significantly reduced. On the other hand, if e is less than 0.15, sintering is not sufficient. Further, when it exceeds 0.35, the Q value is remarkably reduced. Further, when f is less than 0.1, the capacitance value variation (CV
Value) is greater than 0.3 and 1100 to 13
Does not sinter sufficiently at 00 ° C.

The most desirable range is 0.98 ≦ X ≦ 1.00 0.02 ≦ y ≦ 0.03 2.0 ≦ z ≦ 4.0 0.38 ≦ a ≦ 0.42 0.38 ≦ b ≦ 0.42 0.18 ≦ c ≦ 0.22 0.50 ≦ d ≦ 0.60 0.20 ≦ e ≦ 0.30 0.15 ≦ f ≦ 0.25

In the dielectric porcelain composition according to the present invention, CaZr
The basic components consisting of O ₃ and CaTiO ₃ include Si—Li—
By adding a glass component (sintering aid) composed of Y or Si-BY, the reduction of Li or B is suppressed, and sintering is sufficiently performed. Therefore, in a neutral or reducing atmosphere, During firing, it is possible to reduce the variation in capacitance, and further, the capacitance Cap and the temperature characteristic T
The C value, the Q value, the specific resistance ρ, etc. are also sufficiently satisfied.

Therefore, by applying the dielectric porcelain composition of the present invention, the temperature compensation which is extremely stable in quality and sufficiently satisfies the capacitance Cap, the temperature characteristic TC, the Q value, the specific resistance ρ, etc. It is possible to provide a laminated ceramic capacitor for use.

[0017]

Next, examples (including comparative examples) of the present invention will be described.

Calcium carbonate (CaCO ₃ ), titanium dioxide (TiO ₂ ), zirconium oxide (ZrO ₂ ), and manganese carbonate (MnCO ₃ ) are prepared as starting materials so that the ratios are as shown in Tables 1 and 2. Each was weighed. In addition, in this weighing, impurities were weighed without putting them in the eye. Next, these weighed raw materials were put into a pot mill, and further, alumina balls and 2.5 liters of water were put therein. After wet stirring for 15 hours, the stirred product was put in a stainless steel vat and heated at 150 ° C. with a hot-air dryer. Dried for 4 hours. Next, the dried product is coarsely pulverized, and the coarsely pulverized product is baked in a tunnel furnace at 1300 ° C. for 2 hours in the air. Obtained.

On the other hand, in order to obtain a glass component, silicon dioxide (SiO ₂ ), lithium carbonate (Li ₂ CO ₃ ) or boron oxide (B ₂ O ₃ ), and yttrium oxide (Y ₂ O ₃ ) are appropriately weighed. 300 cc of water was added thereto, and the mixture was stirred for 10 hours using an alumina ball in a polyethylene pot, and then temporarily calcined at 1300 ° C. in the atmosphere for 2 hours. This was put into an alumina pot together with 300 cc of water, and ground for 15 hours with an alumina ball. Thereafter, the glass component was dried at 150 ° C. for 4 hours to obtain a glass component powder having an average particle diameter of about 1 μm shown in Tables 1 and 2. Table 1 shows an experiment with lithium carbonate, and Table 2 shows an experiment with boron oxide.

Next, a glass component powder is added to the above basic component powder, and an organic binder composed of an aqueous solution of an acrylate polymer, glycerin and a condensed phosphate is added to the total weight of the basic component and the additional component. 15% by weight, and 50% by weight of water were further added. These were put in a ball mill and ground and mixed for about 20 hours to prepare a slurry of porcelain raw material.

Next, the slurry is placed in a vacuum defoaming machine to remove bubbles. The slurry is placed in a reverse roll coater, and a thin film based on the slurry is formed on a polyester film using the slurry. Above 100
It was dried by heating to ℃ to obtain a green sheet having a thickness of about 25 μm. This sheet is a long sheet, and was used by punching it into a 10 cm square.

On the other hand, as the conductive paste for the internal electrode, 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 put into a stirrer. Obtained by stirring for hours. This conductive paste was printed on one surface of the green sheet through a screen having 50 patterns 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 upward. At this time, the printing surfaces of the adjacent upper and lower sheets were arranged such that their printing surfaces were shifted by about half in the longitudinal direction of the pattern. Further, four green sheets each having a thickness of 60 μm were laminated on each of the upper and lower surfaces of the laminate. Next, the laminate was pressed at a temperature of about 50 ° C. by applying a pressure of about 40 tons in the thickness direction. Thereafter, this laminate was cut into a lattice to obtain about 100 laminated chips.

Next, the laminated chip is placed in a furnace capable of firing in an atmosphere, and is heated at a rate of 100 ° C./h in an air atmosphere.
The temperature was raised to 00 ° C. to burn the organic binder. Thereafter, the atmosphere of the furnace was changed from the atmosphere to an atmosphere of ₂ % by volume of H ₂ + 98% by volume of N ₂ . Then, while maintaining the furnace in the reducing atmosphere as described above, the heating temperature of the laminated chip was set at 6 ° C.
After the temperature was raised from 00 ° C to the sintering temperature at a rate of 100 ° C / h and held at 1100 to 1300 ° C (maximum temperature) x 3 hours, the temperature was lowered to 600 ° C at a rate of 100 ° C / h, and the atmosphere was air atmosphere. 600 ° C in place of (oxidizing atmosphere)
For 30 minutes to perform an oxidation treatment, and then cooled to room temperature to produce a sintered body chip.

Next, a conductive paste composed of Cu, glass frit and vehicle is applied to the side surface of the sintered body chip where the electrodes are exposed, and dried, and this is dried in air at 800 to 90 mm.
Baking at a temperature of 0 ° C. for 15 minutes to form a Cu electrode layer, further depositing copper thereon by electroless plating, and further providing an Sn solder layer thereon by electroplating to form a pair of external electrodes. Was formed.

Thus, the dielectric ceramic layer, the internal electrode,
A multilayer ceramic capacitor composed of external electrodes was obtained. The dimensions of this capacitor are 2.0 mm × 1.25 mm
And the lamination specification is 15 μm × 40 layers. The composition of the porcelain layer after sintering is substantially the same as the mixed composition of the basic component and the additive component before sintering.

Next, the capacitance Cap, the capacitance variation CV, the relative permittivity εs, the temperature coefficient TC, the Q value, and the specific resistance ρ of the completed laminated ceramic capacitor were measured.

The above electric characteristics were measured in the following manner. (1) The relative dielectric constant εs is as follows: temperature 25 ° C., frequency 1 MHz,
The capacitance was measured under the condition of an AC voltage (effective value) of 0.5 V, and the measured value and the facing area of the pair of internal electrodes were 25 mm ^2.
From the thickness of the porcelain layer and 0.05 mm. The capacitance Cap was determined in the same manner. (2) The capacitance value variation CV (%) of the capacitance was calculated by the following formula.

[0029]

(Equation 1)

(3) Temperature coefficient (TC) is 85 ° C.
Capacity (C₈₅) And 25 ° C. capacitance (C _{twenty five}) And measure
It was calculated by the following formula.

[0031]

(Equation 2)

(3) The Q value was measured by a Q meter at a temperature of 25 ° C. and an alternating current of 1 MHz and a voltage [effective value] of 0.5 V. (4) The resistivity ρ (MΩ · cm) was obtained by measuring the resistance value between a pair of external electrodes after applying DC 50 V for 1 minute at a temperature of 25 ° C. and calculating the resistance value based on the measured value and the dimensions.

First, the results of the SiO ₂ —Li ₂ O—Y ₂ O ₃ system glass are shown in Table 1.

[0034]

[Table 1]

As is clear from Table 1, the samples according to the present invention (Sample Nos. 2 to 5, 8 to 11, 14 to 17, 20 to 2)
1, 24-25, 28-29), the capacitance Cap is 950-1050 pF, and the capacitance variation CV value is 2.0%.
Hereinafter, the relative permittivity εs is 30 to 66, and the temperature coefficient T of the permittivity is
C is within ± 30 ppm, Q value is 5,000 or more, resistivity ρ
Was 1 × 10 ⁹ MΩ · cm or more, and a capacitor for temperature compensation having desired characteristics could be obtained. In contrast, x
Is 0.90 (Sample No. 1), the Q value is 1100
And decreased significantly. When x is 1.10 (sample N
o. 6) has a Q value of 2300 and a specific resistance ρ of 5.21 × 1
It became 0 ⁷ MΩ · cm, and sintering was insufficient.

When y is 0 (sample No. 7),
The capacitance Cap was 885 and the relative dielectric constant εs was 25. Further, when y was 0.15 (Sample No. 12), the capacitance Cap was 1320, and the absolute value of the temperature characteristic of the dielectric constant was 60 ppm.

When z is 0.99 (Sample No. 13)
The Q value was remarkably reduced to 1100. Further, even in the case of 5.5 parts by weight (Sample No. 18), the Q value is 139.
It decreased significantly to 0.

When a is 0.3 (sample No. 1)
9) has a Q value of 4200 and a specific resistance ρ of 3.53 × 10 ⁷
MΩ · cm, and sintering was insufficient. Furthermore, when a is 0.
In the case of Sample No. 5 (Sample No. 22), the Q value was remarkably reduced to 1600.

When b is 0.3 (sample No. 2)
3) has a Q value of 4600 and a specific resistance ρ of 2.53 × 10 ⁷
MΩ · cm, and sintering was insufficient. Further, when b is 0.
In the case of Sample No. 5 (Sample No. 25), the Q value was remarkably reduced to 1950.

When c is 0.05 (sample No. 2)
In 6), the capacitance value variation CV value was as large as 4.21. Further, in the case of 0.35 (sample No. 30), the Q value was 4500, the specific resistance ρ was 2.53 × 10 ⁷ MΩ · cm, and the sintering was insufficient.

Further, it was confirmed by ICP quantitative analysis that the dielectric ceramic composition of the present invention had a smaller variation in Li ratio than the conventional one.

Next, the results of the SiO ₂ —B ₂ O ₃ —Y ₂ O ₃ glass are shown in Table 2.

[0043]

[Table 2]

As is clear from Table 2, in the samples according to the present invention (Sample Nos. 32-33, 36-37, 40-41), the capacitance Cap is 950-1050 pF, and the capacitance variation CV value is 2.0%. Hereinafter, the relative dielectric constant εs is 30 to 6
6. The temperature coefficient TC of the dielectric constant was within ± 30 ppm, the Q value was 5,000 or more, and the specific resistance ρ was 1 × 10 ⁹ MΩ · cm or more, and a capacitor for temperature compensation having desired characteristics could be obtained.

On the other hand, when d is 0.35 (sample N
o. 31) has a Q value of 4000 and a specific resistance ρ of 3.66 ×
It was 10 ⁷ MΩ · cm, and sintering was insufficient. Furthermore, d
Is 0.75 (Sample No. 34), the Q value is 160
It decreased significantly to 0.

When e is 0.1 (Sample No. 3)
5) has a Q value of 4200 and a specific resistance ρ of 2.61 × 10 ⁷
MΩ · cm, and sintering was insufficient. Further, if e is 0.
In the case of Sample No. 4 (Sample No. 38), the Q value was significantly reduced to 2010.

When f is 0.05 (sample No. 3)
In 9), the capacitance value variation CV value was as large as 5.21. Further, in the case of 0.35 (sample No. 42), the Q value was 4000 and the specific resistance ρ was 2.11 × 10 ⁷ MΩ · cm, and the sintering was insufficient.

Further, it was confirmed by ICP quantitative analysis that the dielectric ceramic composition of the present invention had a smaller variation in the ratio of B as compared with the conventional one.

The embodiments of the present invention have been described above.
The present invention is not limited to this, and for example, the following modifications are possible. (1) A trace amount (preferably 0.05 to 0.1% by weight) of a mineralizer may be added to the basic components within a range that does not impair the purpose of the present invention to improve sinterability. (2) The starting material for obtaining the basic component may be, for example, an oxide or hydroxide such as CaO or another compound other than those shown in the examples. Further, the starting material of the additional component may be another compound such as an oxide or a hydroxide. (3) The oxidation temperature may be lower than the sintering temperature other than 600 ° C (preferably in the range of 500 ° C to 1000 ° C). That is, various changes can be made in consideration of the electrode of nickel or the like and the oxidation of the porcelain. (4) The firing temperature in the non-oxidizing atmosphere can be variously changed in consideration of the electrode material. When nickel is used as the internal electrode, almost no melt aggregation occurs in the range of 1050 ° C to 1200 ° C. (5) Sintering may be performed in a neutral atmosphere. (6) It is applicable to general ceramic capacitors other than the laminated ceramic capacitor. (7) Both Li and B may be contained in the glass component.
Further, the present invention is applicable to other glass components having a low melting point.

[0050]

As described above, the dielectric porcelain of the present invention is
The basic components consisting of CaZrO ₃ and CaTiO ₃ are Si
By adding a glass component (sintering aid) composed of -Li-Y or Si-BY, capacity variation can be reduced during firing in a neutral or reducing atmosphere. And the relative dielectric constant εs and the temperature characteristic T
The C value, the Q value, the specific resistance ρ, etc. are also sufficiently satisfied.

Therefore, by applying the non-reducing dielectric ceramic composition of the present invention, the quality is extremely stable and the capacitance Cap, the temperature characteristic TC, the Q value, the specific resistance ρ and the like are sufficiently satisfied. Thus, it is possible to provide a laminated ceramic capacitor for temperature compensation.

[Brief description of the drawings]

FIG. 1 shows SiO ₂ and Li of the dielectric ceramic composition of the present invention.
₂ O, and is a triangular diagram of Y ₂ O _3.

FIG. 2 shows SiO ₂ and B of the dielectric ceramic composition of the present invention.
₂ O _3, and is a triangular diagram of Y ₂ O _3.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4G031 AA01 AA04 AA08 AA11 AA12 AA19 AA28 AA30 BA09 5E001 AB03 AC09 AE03 AJ02 5E082 AB03 BC15 EE04 EE11 EE23 EE35 FF05 FG06 FG26 FG54 PP03 5G303 AB11AB02CB CB18 CB30 CB35 CB39 CB40

Claims (2)

[Claims] 1. The formula (CaO) _x (Zr _1-y .Ti _y )
O ₂ (however, 0.95 ≦ x ≦ 1.05, 0.01 ≦ y ≦
With respect to 100 parts by weight of the basic component represented by the numerical value in the range of 0.10), 1 to 5 parts by weight of MnCO ₃ and the general formula aSiO ₂ -bLi ₂ O-cY ₂ O ₃ (however, 0.3
5 ≦ a ≦ 0.45, 0.35 ≦ b ≦ 0.45, 0.1 ≦
The glass component represented by (a numerical value in the range of c ≦ 0.3) is set to 0.
5 to 5 parts by weight of the dielectric ceramic composition. 2. Formula (CaO) _x (Zr _{1 -y} · Ti _y )
O ₂ (however, 0.95 ≦ x ≦ 1.05, 0.01 ≦ y ≦
With respect to 100 parts by weight of a basic component represented by a numerical value in the range of 0.10), 1 to 5 parts by weight of MnCO ₃ and a general formula dSiO ₂ -eB ₂ O ₃ -fY ₂ O ₃ (however,
0.4 ≦ d ≦ 0.7, 0.15 ≦ e ≦ 0.35, 0.1
A dielectric ceramic composition characterized by containing 0.5 to 5 parts by weight of a glass component represented by the following formula: ≦ f ≦ 0.3).