JP4556607B2 - Dielectric ceramic composition and electronic component - Google Patents

Description

  The present invention relates to a dielectric ceramic composition used as a dielectric layer of an electronic component such as a multilayer ceramic capacitor, and an electronic component such as a multilayer ceramic capacitor using the dielectric ceramic composition as a dielectric layer.

  Multilayer ceramic capacitors as electronic components have high dielectric constant, long life of insulation resistance IR, good DC bias characteristics (low relative dielectric constant change over time), and good temperature characteristics Is also required. In particular, depending on the application, the temperature characteristics are required to be flat in a wide temperature range.

  In recent years, multilayer ceramic capacitors have been used in various electronic devices such as an engine electronic control unit (ECU), a crank angle sensor, and an antilock brake system (ABS) module mounted in an engine room of an automobile. Since these electronic devices are for performing engine control, drive control, and brake control stably, it is required that the circuit has good temperature stability.

  The environment in which these electronic devices are used is expected to decrease to about −20 ° C. or lower in winter in cold regions, and to increase to about + 130 ° C. or higher in summer after engine startup. Recently, there is a tendency to reduce the number of wire harnesses that connect an electronic device and its control target device, and the electronic device may be installed outside the vehicle. For this reason, the environment for electronic devices has become increasingly severe. Therefore, capacitors used in these electronic devices need to have flat temperature characteristics over a wide temperature range. Specifically, it is not sufficient for the capacity-temperature characteristic to satisfy the EIA standard X7R characteristic (−55 to 125 ° C., ΔC / C = within ± 15%), but the EIA standard X8R characteristic (−55 to 150 ° C.). , ΔC / C = within ± 15%) is required.

  There are several proposals for dielectric ceramic compositions that satisfy the X8R characteristics.

In Patent Documents 1 and 2, in order to satisfy X8R characteristics in a dielectric ceramic composition containing BaTiO ₃ as a main component, the Curie temperature is increased to a high temperature side by replacing Ba in BaTiO ₃ with Bi, Pb or the like. It has been proposed to shift. Patent Documents 3 to 7 also propose that the X8R characteristic is satisfied by selecting a composition of BaTiO ₃ + CaZrO ₃ + ZnO + Nb ₂ O ₅ system. However, in any of the techniques of Patent Documents 1 to 7, since Pb, Bi, and Zn that easily evaporate and fly are used, firing in an oxidizing atmosphere such as in air is a prerequisite. For this reason, inexpensive base metals such as Ni cannot be used for the internal electrodes of the capacitor, and expensive noble metals such as Pd, Au, and Ag must be used.

  On the other hand, the present applicant has already proposed the following dielectric ceramic composition as having a high dielectric constant, satisfying X8R characteristics, and enabling firing in a reducing atmosphere ( Patent Documents 8 and 9).

The dielectric ceramic composition described in Patent Document 8 is
BaTiO _{3 as the} main component,
A first subcomponent comprising at least one selected from MgO, CaO, BaO, SrO and Cr ₂ O ₃ ;
A second subcomponent represented by (Ba, Ca) _x SiO _{2 + x} (where x = 0.8 to 1.2);
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
And at least a fourth subcomponent including an oxide of R1 (wherein R1 is at least one selected from Sc, Er, Tm, Yb, and Lu);
The ratio of each subcomponent to 100 moles of the main component is
1st subcomponent: 0.1-3 mol,
Second subcomponent: 2 to 10 mol,
Third subcomponent: 0.01 to 0.5 mol,
Fourth subcomponent: 0.5 to 7 moles (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone).

The dielectric ceramic composition described in Patent Document 9 is
A main component comprising barium titanate;
A first subcomponent comprising at least one selected from MgO, CaO, BaO, SrO and Cr ₂ O ₃ ;
A second subcomponent containing silicon oxide as a main component;
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
A fourth subcomponent comprising an oxide of R1, wherein R1 is at least one selected from Sc, Er, Tm, Yb and Lu;
A fifth subcomponent comprising CaZrO ₃ or CaO + ZrO ₂ ;
MnO as a seventh subcomponent,
The ratio of each component to 100 moles of the main component is
First subcomponent: 0.1-3 mol in terms of oxide (in terms of metal element, Mg, Ca, Ba and Sr are 0.1-3 mol, Cr is 0.2-6 mol),
Second subcomponent: 2 to 10 mol,
Third subcomponent: 0.01 to 0.5 mol in terms of oxide (in terms of metal element, V is 0.02 to 1 mol, Mo and W are 0.01 to 0.5 mol),
Fourth subcomponent: 0.5 to 7 mol (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone),
Fifth subcomponent: 0 <fifth subcomponent ≦ 5 mol,
Seventh subcomponent: 0.5 mol or less in terms of oxide (Mn is 0.5 mol or less in terms of metal element).

  In any of these techniques of Patent Documents 8 and 9, the ratio of the first subcomponent such as MgO to 100 mol of the main component is 0.1 mol or more in terms of oxide.

  On the other hand, the present applicant has also proposed a technique that satisfies the X8R characteristics while setting the ratio of the first subcomponent such as MgO to less than 0.1 mol in terms of oxide (Patent Document 10).

The dielectric ceramic composition described in Patent Document 10 is
A main component comprising barium titanate;
A first subcomponent comprising an oxide of AE (wherein AE is at least one selected from Mg, Ca, Ba and Sr);
A second subcomponent comprising an oxide of R (where R is at least one selected from Y, Dy, Ho and Er);
The ratio of each subcomponent to 100 moles of the main component is
First subcomponent: 0 mol in terms of oxide <first subcomponent <0.1 mol,
Second subcomponent: 1 mol <second subcomponent <7 mol.

  According to the techniques of the above-mentioned Patent Documents 8 to 10 by the present applicant, the dielectric constant is certainly high, the X8R characteristics are satisfied, and firing in a reducing atmosphere is possible.

However, particularly for the above-described multilayer ceramic capacitor for in-vehicle use, it is desirable to flatten the temperature characteristics up to an even higher temperature that exceeds the X8R characteristics.
Japanese Patent Laid-Open No. 10-25157 Japanese Patent Laid-Open No. 9-40465 JP-A-4-295048 JP-A-4-292458 Japanese Unexamined Patent Publication No. Hei 4-29259 JP-A-5-109319 JP-A-6-243721 JP 2000-154057 A JP 2001-192264 A (Patent 3348081) JP 2002-255639 A (Patent 334003)

  The object of the present invention is a high relative dielectric constant, which enables firing in a reducing atmosphere, and further higher temperatures that exceed the EIA standard X8R characteristics (−55 to 150 ° C., within ΔC / C = ± 15%). It is to provide a dielectric ceramic composition in which the capacitance-temperature characteristics are flattened and the deterioration of the insulation resistance is suppressed. Another object of the present invention is to provide an electronic component such as a multilayer ceramic capacitor that can be reduced in size and increased in capacity using such a dielectric porcelain composition, and is particularly suitable for thin layer size reduction.

In anticipation of future demands from the electronic component industry, the present inventors have studied a technology that can flatten the capacity-temperature characteristics up to a higher temperature that is higher than the X8R characteristics of the EIA standard. As a result, for the composition satisfying the conventional X8R characteristics, the ratio of the third subcomponent (y3) is increased as compared with the conventional ratio, so that the rate of change in capacity on the high temperature side exceeding 150 ° C. rapidly decreases. It was found that can be suppressed.
On the other hand, it has been found that if the ratio of the third subcomponent is simply increased, the deterioration of the insulation resistance on the high temperature side exceeding 150 ° C. is remarkably unusable. Therefore, by increasing the ratio of the third subcomponent while controlling the ratio of the seventh subcomponent (y7) according to the ratio of the third subcomponent (y3), the deterioration of the insulation resistance on the high temperature side is reduced. It has been found that it can be suppressed.

That is, according to the present invention,
A main component comprising barium titanate;
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
A second subcomponent containing silicon oxide as a main component;
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
A fourth subcomponent comprising an oxide of R1, wherein R1 is at least one selected from Sc, Er, Tm, Yb and Lu;
A fifth subcomponent comprising CaZrO ₃ or CaO + ZrO ₂ ;
A dielectric ceramic composition having a seventh subcomponent containing one or both of MnO and Cr ₂ O ₃ ,
The ratio of the third subcomponent with respect to 100 mol of the main component (y3. However, the value converted to a metal element) is 1 to 6 mol (excluding 1 mol),
A dielectric ceramic composition is provided in which the ratio of the seventh subcomponent (y7, where the value is converted into a metal element) is 0.25 to 2.5 times y3.

Preferably, the ratio of each subcomponent (y1, y2, y4, y5) to 100 moles of the main component is
First subcomponent (y1): 0.1 to 3 mol,
Second subcomponent (y2): 2 to 10 mol,
Fourth subcomponent (y4): 0.5 to 7 mol (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone),
5th subcomponent (y5): 5 mol or less (however, 0 mol is excluded).

The third subcomponent includes at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ , and is preferably composed of at least one selected from these three compounds, and more preferably Includes at least V ₂ O ₅ . The seventh subcomponent contains one or both of MnO and Cr ₂ O ₃ , but is preferably composed of one or both of these two compounds, and more preferably contains at least MnO.

According to the present invention,
A main component comprising barium titanate;
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
A second subcomponent containing silicon oxide as a main component;
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
A fourth subcomponent comprising an oxide of R1, wherein R1 is at least one selected from Sc, Er, Tm, Yb and Lu;
A fifth subcomponent comprising CaZrO ₃ or CaO + ZrO ₂ ;
A dielectric ceramic composition having a seventh subcomponent containing one or both of MnO and Cr ₂ O ₃ ,
The ratio (y1 to y5) of each subcomponent with respect to 100 moles of the main component is
First subcomponent (y1): 0.1 to 3 mol,
Second subcomponent (y2): 2 to 10 mol,
3rd subcomponent (y3. However, the value converted into the metal element): 1-6 mol (however, except 1 mol),
Fourth subcomponent (y4): 0.5 to 7 mol (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone),
5th subcomponent (y5): 5 mol or less (however, excluding 0 mol),
A dielectric ceramic composition in which the ratio of the seventh subcomponent (y7, where converted to a metal element) is 0.25 to 2.5 times y3 is provided.

  Preferably, the sixth subcomponent further includes an oxide of R2 (wherein R2 is at least one selected from Y, Dy, Ho, Tb, Gd and Eu), and the ratio of the sixth subcomponent (y6 ) Is 9 mol or less (excluding 0 mol, the number of moles of the sixth subcomponent is the ratio of R2 alone) with respect to 100 mol of the main component.

  Preferably, the total ratio (y4 + y6) of the fourth subcomponent and the sixth subcomponent is 13 mol or less (excluding 0 mol) with respect to 100 mol of the main component. The moles of the fourth subcomponent and the sixth subcomponent. The number is the ratio of R1 and R2 alone).

Preferably, the second subcomponent is at least one selected from SiO ₂ , MO (where M is at least one element selected from Ba, Ca, Sr and Mg), Li ₂ O and B ₂ O _3. Represented by seeds. The second subcomponent is considered to function as a sintering aid.

  In the fifth subcomponent, the molar ratio of Ca and Zr is arbitrary, but preferably Ca / Zr = 0.5 to 1.5, more preferably Ca / Zr = 0.8 to 1.5, particularly Preferably, Ca / Zr = 0.9 to 1.1.

Preferably, as the eighth subcomponent, an oxide of A (where A is at least one selected from the group of cationic elements having an effective ionic radius of 0.065 nm to 0.085 nm at the time of 6 coordination) Have.
More preferably, the ratio (y8) of the eighth subcomponent is 0 to 4 mol (excluding 0 mol and 4 mol, values converted to A oxide) with respect to 100 mol of the main component.
In addition, the ion radius here is a value based on literature "RD Shannon, Acta Crystallogr., A32, 751 (1976)".

  Preferably, the oxide A included in the eighth subcomponent is at least one selected from the group of cationic elements of Al, Ga, and Ge.

  The electronic component according to the present invention is not particularly limited as long as it is an electronic component having a dielectric layer. For example, the electronic component is a multilayer ceramic capacitor element having a capacitor element body in which internal electrodes are alternately laminated together with dielectric layers. is there. In the present invention, the dielectric layer is composed of any one of the above dielectric ceramic compositions. The conductive material contained in the internal electrode layer is not particularly limited, but is Ni or Ni alloy, for example.

In the present invention, first, the ratio of the third subcomponent (at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ) (y3, where the value is converted to a metal element) is 100 mol of the main component. 1 to 6 mol (excluding 1 mol). As a result, a sudden drop in the capacity change rate on the high temperature side (for example, 175 ° C.) exceeding 150 ° C. is suppressed. Then, the ratio of the seventh subcomponent (one or both of MnO and _Cr 2 _{O 3)} (y7. However, the value in terms of metal element), and controls in accordance with the ratio of the third subcomponent (y3). Thereby, the deterioration of the insulation resistance on the high temperature side exceeding 150 ° C., which occurs when the ratio (y3) of the third subcomponent is simply increased, is suppressed. Specifically, for example, an insulation resistance of 10 ⁶ Ω or more at 175 ° C. can be ensured.

  Due to such an action, according to the present invention, the dielectric constant is high, and firing in a reducing atmosphere is possible, and the X8R characteristic of EIA standard (−55 to 150 ° C., ΔC / C = ± 15%) The dielectric ceramic composition in which the capacity-temperature characteristics are flattened up to the above-described further high temperature and the deterioration of the insulation resistance is suppressed can be provided. Further, according to the present invention, by using such a dielectric ceramic composition, it is possible to realize a reduction in size and increase in capacity, and in particular, it is possible to provide an electronic component such as a multilayer ceramic capacitor corresponding to a reduction in size of a thin layer.

  Further, by adding a cation element group (eighth subcomponent) whose effective ionic radius at the time of six coordination falls within a predetermined range, the temperature from the room temperature to the high temperature part can be obtained without affecting the target temperature characteristics described above. The IR temperature dependency up to can be improved.

  “IR temperature dependency” is an index for ascertaining how the insulation resistance IR fluctuates with respect to a temperature change. This IR temperature dependency can be evaluated by calculating a rate (change rate) at which IR at a predetermined temperature (for example, 175 ° C.) changes with respect to IR at a reference temperature (for example, room temperature 25 ° C.). It can be determined that the IR temperature dependency is better as the IR change rate between a plurality of temperatures is smaller, and the IR temperature dependency is worse as the IR change rate is larger. Even if the temperature characteristic of the capacitance is flattened to an even higher temperature equal to or higher than X8R of the EIA standard, if the IR temperature dependency is poor, actual use as a product may be difficult.

In the present invention, room temperature (25 ° C.) and high temperature part (175 ° C.) are exemplified as a plurality of temperatures, and the insulation resistance at each temperature is IR ₂₅ and IR _175. By calculating the magnitude of “digit loss”, the IR temperature dependency is evaluated for good or bad.
log (IR ₁₇₅ / IR ₂₅ ) ... Equation 1

  That is, by adding the eighth subcomponent composed of a specific element group, the IR temperature dependence from room temperature (25 ° C.) to the high temperature part (175 ° C.) can be achieved without affecting the target temperature characteristics. small. Specifically, the IR digit loss represented by the above formula 1 can be set to −3.5 or more.

  The electronic component according to the present invention is not particularly limited, and examples thereof include a multilayer ceramic capacitor, a piezoelectric element, a chip inductor, a chip varistor, a chip thermistor, a chip resistor, and other surface mount (SMD) chip type electronic components.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention, and FIG. 2 is a graph showing capacitance-temperature characteristics of a sample 45 corresponding to an example of the present invention and a sample 1 corresponding to a comparative example.

  In this embodiment, the multilayer ceramic capacitor 1 shown in FIG. 1 is illustrated as an electronic component, and the structure and manufacturing method thereof will be described.

Multilayer Ceramic Capacitor As shown in FIG. 1, a multilayer ceramic capacitor 1 as an electronic component according to an embodiment of the present invention has a capacitor element body 10 in which dielectric layers 2 and internal electrode layers 3 are alternately stacked. . At both ends of the capacitor element body 10, a pair of external electrodes 4 are formed which are electrically connected to the internal electrode layers 3 arranged alternately in the element body 10. The internal electrode layers 3 are laminated so that the end faces are alternately exposed on the surfaces of the two opposite ends of the capacitor element body 10. The pair of external electrodes 4 are formed at both ends of the capacitor element body 10 and are connected to the exposed end surfaces of the alternately arranged internal electrode layers 3 to constitute a capacitor circuit.

  The outer shape and dimensions of the capacitor element body 10 are not particularly limited and can be appropriately set according to the application. Usually, the outer shape is substantially a rectangular parallelepiped shape, and the dimensions are usually vertical (0.4 to 5.6 mm) × It can be about horizontal (0.2-5.0 mm) × height (0.2-1.9 mm).

The dielectric layer dielectric layer 2 contains the dielectric ceramic composition according to the present invention.
The dielectric ceramic composition of the present invention comprises:
Barium titanate (preferably represented by the composition formula Ba _m TiO _{2 + m} , m is 0.995 ≦ m ≦ 1.010, and the ratio of Ba to Ti is 0.995 ≦ Ba / Ti ≦ 1.010 A main component containing
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
A second subcomponent containing silicon oxide as a main component;
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
A fourth subcomponent comprising an oxide of R1, wherein R1 is at least one selected from Sc, Er, Tm, Yb and Lu;
A fifth subcomponent comprising CaZrO ₃ or CaO + ZrO ₂ ;
And a seventh subcomponent including one or both of MnO and Cr ₂ O ₃ .

  In the present invention, first, the ratio of the third subcomponent (y3, where converted to a metal element) is 1 to 100 mol of the main component with respect to the dielectric composition satisfying the X8R characteristic. It is characterized by 6 mol (excluding 1 mol), preferably 1.5-4 mol.

The ratio of the third subcomponent (y3) was converted not to the molar ratio of “oxide” such as V ₂ O ₅ , MoO ₃ and WO ₃ but to “metal elements, ie, V, Mo and W”. Is the molar ratio of “when”. That is, for example, when V oxide is used as the third subcomponent, the ratio of the third subcomponent (y3) of 2 mol means that the ratio of V is 2 mol. The ratio in terms of oxide (V ₂ O ₅ ) means 1 mole. Moreover, when the oxide of Mo is used as the third subcomponent, the ratio of the third subcomponent (y3) is 2 mol. This means that the ratio of Mo is 2 mol and this is the oxide (MoO ₃ ). The ratio when converted to 2 is also 2 mol. About W, it follows the case of Mo.

The third subcomponent (V ₂ O ₅ , MoO ₃ and WO ₃ ) has an effect of flattening the capacity-temperature characteristics above the Curie temperature, particularly an effect of suppressing a sudden drop in the capacity change rate on the high temperature side, and an IR lifetime. It shows the effect of improving. When the ratio of the third subcomponent (y3) is 1 mol or less in terms of metal element, the capacity change rate on the high temperature side (above 150 ° C.) deteriorates. On the other hand, when the ratio (y3) of the third subcomponent is too large, it becomes difficult to suppress the deterioration of the insulation resistance (IR) even by adjustment with the seventh subcomponent described later.

The third subcomponent contains at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ , but preferably comprises at least one selected from these three compounds, more preferably at least V ₂ O ₅ is included. When using 2 or more types in combination, particularly preferred combinations are V ₂ O ₅ + MoO ₃ , V ₂ O ₅ + WO ₃ , V ₂ O ₅ + MoO ₃ + WO ₃ .

  In the case where the third subcomponent is composed of a plurality of oxides, the total ratio may be in the range described above. That is, the constituent ratio of each oxide in the third subcomponent is arbitrary.

  In the present invention, secondly, the ratio of the seventh subcomponent (y7, where the value is converted into a metal element) is set to 0. 0 of the ratio of the third subcomponent (y3, where the value is converted into a metal element). It is characterized in that it is controlled in the range of 25 to 2.5 times, preferably 0.5 to 1.5 times. Since y3 is controlled in the range of 1 to 6 mol (excluding 1 mol) in terms of a metal element as described above, y7 here is 0 with respect to 100 mol of the main component. Determined in the range of 25 to 15 moles.

Note that the conversion of the ratio of the seventh subcomponent (y7) is the same as the ratio of the third subcomponent (y3), not the molar ratio of “oxide” such as MnO and Cr ₂ O ₃ but “metal”. It is the molar ratio of “when converted to elements, ie, Mn and Cr”. That is, for example, when an oxide of Mn is used as the seventh subcomponent, the ratio (y7) of the seventh subcomponent is 1.5 mol as a result of 0.25 to 2.5 times y3. It means that the ratio of Mn is 1.5 mol, and the ratio when converted to oxide (MnO) is also 1.5 mol. Further, when the oxide of Cr is used as the seventh subcomponent, the ratio of the seventh subcomponent (y7) is 1.5 mol. The ratio of Cr is 1.5 mol. The ratio when converted to (Cr ₂ O ₃ ) is 0.75 mol.

The seventh subcomponent (MnO and / or Cr ₂ O ₃ ) has an effect of promoting sintering, an effect of increasing IR, particularly an effect of suppressing IR deterioration on the high temperature side, and an effect of improving IR life. Indicates. If the ratio of the seventh subcomponent (y7) is less than 0.25 times y3, it is not possible to suppress deterioration of the insulation resistance (IR) on the high temperature side (above 150 ° C.). On the other hand, when the ratio of the seventh subcomponent (y7) exceeds 2.5 times y3, the capacity-temperature characteristic on the high temperature side (above 150 ° C.) is adversely affected.

The seventh subcomponent contains one or both of MnO and Cr ₂ O ₃ , but preferably comprises one or both of these two compounds, and more preferably contains at least MnO.

  In addition, what is necessary is just to make it a total ratio become the range mentioned above in the case where a 7th subcomponent is comprised with a some oxide. That is, the constituent ratio of each oxide in the seventh subcomponent is arbitrary.

  In other words, in the present invention, the ratio of the third subcomponent (y3, where the value converted to the metal element) is in the range of 1 to 6 mol (excluding 1 mol) with respect to 100 mol of the main component, The ratio (y7 / y3) of the ratio of the seven subcomponents (y7, where converted into metal elements) and the ratio of the third subcomponent (y3, where converted into metal elements) is 0.25. The ratio of y7 is determined so as to be in a range of ˜2.5.

In addition, the ratio (y1, y2, y4, y5) of each of the subcomponents with respect to 100 moles of the main component is
First subcomponent (y1): 0.1 to 3 mol,
Second subcomponent (y2): 2 to 10 mol,
Fourth subcomponent (y4): 0.5 to 7 mol (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone),
5th subcomponent (y5): 5 mol or less (however, excluding 0 mol),
Preferably,
y1: 0.5-2.5 mol,
y2: 2 to 5 mol,
y4: 0.5-5 mol,
y5: 0.5-3 mol.

Note that the ratio of the fourth subcomponent is not the molar ratio of the R1 oxide but the molar ratio of R1 alone. That is, for example, when an oxide of Yb is used as the fourth subcomponent, the ratio of the fourth subcomponent is 1 mol. The ratio of Yb ₂ O ₃ is not 1 mol but the ratio of Yb is 1 mol. It means that.

  In this specification, each oxide constituting the main component and each subcomponent is represented by a stoichiometric composition, but the oxidation state of each oxide may be out of the stoichiometric composition. However, the said ratio of each subcomponent is calculated | required by converting into the oxide of the said stoichiometric composition from the metal amount contained in the oxide which comprises each subcomponent.

  By containing the first to fifth subcomponents, the X8R characteristic can be satisfied while maintaining a high dielectric constant. Preferred ratios and reasons for the first, second, fourth and fifth subcomponents are as follows.

  The first subcomponent (MgO, CaO, BaO, and SrO) exhibits an effect of flattening the capacity-temperature characteristic. If the ratio (y1) of the first subcomponent is too small, the capacity-temperature change rate becomes large. On the other hand, when there is too much y1, sinterability will deteriorate. The composition ratio of each oxide in the first subcomponent is arbitrary.

  The second subcomponent (containing silicon oxide as a main component) mainly acts as a sintering aid, but has an effect of improving the defective rate of the initial insulation resistance when thinned. When the ratio (y2) of the second subcomponent is too small, the capacity-temperature characteristic is deteriorated and IR (insulation resistance) is lowered. On the other hand, if the amount of y2 is too large, the IR lifetime becomes insufficient, and a rapid decrease in dielectric constant occurs.

Preferably, the second subcomponent is SiO ₂ , MO (where M is at least one element selected from Ba, Ca, Sr and Mg), at least one selected from Li ₂ O and B ₂ O _3. It is represented by

More preferably, the second subcomponent is represented by (Ba, Ca) _x SiO _{2 + x} (where x = 0.7 to 1.2). BaO and CaO in [(Ba, Ca) _x SiO _{2 + x} ] as a more preferred embodiment of the _second subcomponent are also included in the first subcomponent, but (Ba, Ca) _x SiO _{2 + x} which is a composite oxide is Since the melting point is low and the reactivity with respect to the main component is good, in the present invention, it is preferable to add BaO and / or CaO as the composite oxide. _{X in} (Ba, Ca) _x SiO _{2 + x} as a more preferred embodiment of the _second subcomponent is preferably 0.7 to 1.2, more preferably 0.8 to 1.1. If x is too small, that is, if SiO ₂ is too much, it reacts with the main component BaTiO ₃ to deteriorate the dielectric properties. On the other hand, if x is too large, the melting point becomes high and the sinterability is deteriorated, which is not preferable. In addition, the ratio of Ba and Ca is arbitrary and may contain only one side.

  The fourth subcomponent (R1 oxide) exhibits the effect of shifting the Curie temperature to the high temperature side and the effect of flattening the capacity-temperature characteristics. If the ratio of the fourth subcomponent (y4) is too small, such an effect is insufficient and the capacity-temperature characteristics are deteriorated. On the other hand, when y2 is too large, the sinterability tends to deteriorate. Among the fourth subcomponents, Yb oxide is preferable because it has a high characteristic improvement effect and is inexpensive.

The fifth subcomponent (CaZrO ₃ ) exhibits the effect of shifting the Curie temperature to the high temperature side and the effect of flattening the capacity-temperature characteristics. In addition, the CR product and the DC breakdown strength are improved. However, if the ratio of the fifth subcomponent (y5) is too large, the IR accelerated life is remarkably deteriorated and the capacity-temperature characteristic (X8R characteristic) is deteriorated. The addition form of CaZrO ₃ is not particularly limited, and examples thereof include oxides composed of Ca such as CaO, carbonates such as CaCO ₃ , organic compounds, and CaZrO ₃ . The ratio of Ca and Zr is not particularly limited and may be determined so as not to be dissolved in the main component BaTiO ₃ , but the molar ratio of Ca to Zr (Ca / Zr) is preferably 0.5 to 1. 5, More preferably, it is 0.8-1.5, More preferably, it is 0.9-1.1.

  The dielectric ceramic composition of the present invention contains an R2 oxide (wherein R2 is at least one selected from Y, Dy, Ho, Tb, Gd and Eu) as a sixth subcomponent, if necessary. The ratio of the sixth subcomponent (y6) is preferably 9 mol or less (excluding 0 mol) with respect to 100 mol of the main component. The number of moles of the sixth subcomponent is the ratio of R2 alone. ), More preferably 0.5 to 9 mol. This sixth subcomponent (R2 oxide) exhibits the effect of improving IR and IR lifetime, and has little adverse effect on the capacity-temperature characteristics. However, if the ratio (y6) of the R2 oxide is too large, the sinterability tends to deteriorate. Of the sixth subcomponents, Y oxide is preferred because of its high effect of improving characteristics and low cost.

  The total ratio of the fourth subcomponent and the sixth subcomponent (y4 + y6) is preferably 13 mol or less (excluding 0 mol) with respect to 100 mol of the main component. The moles of the fourth subcomponent and the sixth subcomponent. The number is the ratio of R1 and R2 alone), more preferably 10 moles or less. This is for maintaining good sinterability.

  In the dielectric ceramic composition of the present invention, as an eighth subcomponent, an oxide of A (where A is selected from a group of cationic elements having an effective ion radius of 0.065 nm to 0.085 nm at the time of six coordination. It is preferable to further have at least one kind.

  The eighth subcomponent does not significantly affect the capacity-temperature characteristics and has the effect of improving the IR temperature dependency.

  The eighth sub-component cationic element group includes I (0.067 nm), Ge (0.067 nm), Al (0.0675 nm), Cu (0.068 nm), Fe (0.069 nm), Ni ( 0.070 nm), Au (0.071 nm), As (0.072 nm), Ga (0.076 nm), At (0.076 nm), Os (0.077 nm), Nb (0.078 nm), Ta (0 0.078 nm), Co (0.079 nm), Rh (0.080 nm), Ir (0.082 nm), Ru (0.082 nm), Sn (0.083 nm), P (0.052 nm), K (0.152 nm) is not included. In addition, the number in parenthesis shows the effective ion radius at the time of 6 coordination. The same applies hereinafter.

  Among the cation element group, it is preferable to use an element having an effective ion radius of 0.067 to 0.076 nm at the time of six coordination. Such preferred element groups include I, Ge, Al, Cu, Fe, Ni, Au, As, Ga, At, and more preferably at least selected from the cationic element group of Al, Ga, Ge. One type is used, more preferably at least Al. When two or more types are used in combination, particularly preferred combinations are Al + Ga and Al + Ge.

  The ratio (y8) of the eighth subcomponent is a value converted to A oxide with respect to 100 mol of the main component, preferably 0 to 4 mol (excluding 0 mol and 4 mol), more preferably It is 0-3.5 mol (however, except 0 mol), More preferably, it is 0.5-3.5 mol, Most preferably, it is 1-1.5 mol. By adding even a small amount of the eighth subcomponent, the effect of improving IR temperature dependency is exhibited. On the other hand, if the ratio (y8) of the eighth subcomponent is too large, the capacity-temperature characteristic tends to deteriorate.

The ratio of the eighth subcomponent is not the molar ratio of A alone but the molar ratio of A oxide. That is, for example, when an Al oxide is used as the eighth subcomponent, the ratio of the eighth subcomponent is 1 mol. The ratio of Al ₂ O ₃ is not 1 mol but the ratio of Al ₂ O ₃ is 1 mol. It means that.

  In addition, when using 2 or more types of several elements (oxide) as an 8th subcomponent, what is necessary is just to make it a total content be the said range with respect to 100 mol of said main components. That is, the constituent ratio of each oxide in the eighth subcomponent is arbitrary.

In addition, when at least one of Sr, Zr, and Sn substitutes Ba or Ti in the main component constituting the perovskite structure, the Curie temperature shifts to a low temperature side, so that the capacity-temperature characteristics at 125 ° C. or higher Becomes worse. For this reason, it is preferable not to use BaTiO ₃ [for example, (Ba, Sr) TiO ₃ ] containing these elements as a main component. However, there is no particular problem as long as the level is contained as an impurity (about 0.1 mol% or less of the entire dielectric ceramic composition).

  The average crystal grain size of the dielectric ceramic composition of the present invention is not particularly limited, and may be appropriately determined from a range of, for example, 0.1 to 3 μm according to the thickness of the dielectric layer.

  Capacitance-temperature characteristics tend to deteriorate as the dielectric layer is thinner, and worsen as the average crystal grain size is reduced. Therefore, the dielectric ceramic composition of the present invention is particularly effective when the average crystal grain size needs to be reduced, specifically when the average crystal grain size is 0.1 to 0.5 μm. is there. In addition, if the average crystal grain size is reduced, the IR lifetime becomes longer, and the change with time of the capacity under a direct current electric field is reduced. From this point, the average crystal grain size is preferably small as described above. .

  The Curie temperature (phase transition temperature from ferroelectric to paraelectric) of the dielectric ceramic composition of the present invention can be changed by selecting the composition, but the temperature characteristics on the high temperature side that are higher than the X8R characteristics can be obtained. In order to improve, it is preferably 120 ° C. or higher, more preferably 123 ° C. or higher. The Curie temperature can be measured by DSC (differential scanning calorimetry) or the like.

  The thickness of the dielectric layer composed of the dielectric ceramic composition of the present invention is usually 40 μm or less, particularly 30 μm or less per layer. The lower limit of the thickness is usually about 2 μm.

  The dielectric ceramic composition of the present invention is effective in improving the capacitance-temperature characteristics (particularly on the high temperature side exceeding 150 ° C.) of the multilayer ceramic capacitor having such a thinned dielectric layer. The number of dielectric layers stacked is usually about 2 to 300.

  The multilayer ceramic capacitor using the dielectric ceramic composition of the present invention is suitable for use as an electronic device for equipment used in a high temperature environment of 80 ° C. or more, particularly 125 to 175 ° C. In such a temperature range, the capacitance temperature characteristic satisfies the EIA standard R characteristic and further satisfies the X8R characteristic, and also in a high temperature region exceeding 150 ° C. (for example, 175 ° C.). It is possible to satisfy the temperature change rate of the capacity within ± 15%. EIAJ standard B characteristics [capacity change rate within ± 10% at −25 to 85 ° C. (reference temperature 20 ° C.)] and EIA standard X7R characteristics (−55 to 125 ° C., ΔC = within ± 15%) at the same time It is possible to be satisfied.

  In a multilayer ceramic capacitor, an AC electric field of 0.02 V / μm or more, particularly 0.2 V / μm or more, more preferably 0.5 V / μm or more, and generally about 5 V / μm or less is superimposed on the dielectric layer. Then, a DC electric field of 5 V / μm or less is applied, but even if such an electric field is applied, the temperature characteristics of the capacitance are stable.

Although the conductive material contained in the internal electrode layer 3 is not particularly limited, a base metal can be used because the constituent material of the dielectric layer 2 has reduction resistance. As the base metal used as the conductive material, Ni or Ni alloy is preferable. The Ni alloy is preferably an alloy of Ni and one or more elements selected from Mn, Cr, Co, and Al, and the Ni content in the alloy is preferably 95% by weight or more.

  In addition, in Ni or Ni alloy, various trace components, such as P, may be contained about 0.1 wt% or less.

  The thickness of the internal electrode layer may be appropriately determined according to the application, etc., but it is usually preferably about 0.5 to 5 μm, particularly preferably about 0.5 to 2.5 μm.

The conductive material contained in the external electrode external electrode 4 is not particularly limited, but in the present invention, inexpensive Ni, Cu, and alloys thereof can be used.

  The thickness of the external electrode may be appropriately determined according to the use, etc., but is usually preferably about 10 to 50 μm.

Manufacturing Method of Multilayer Ceramic Capacitor A multilayer ceramic capacitor using the dielectric ceramic composition of the present invention is a green chip produced by a normal printing method or sheet method using a paste, as in the case of a conventional multilayer ceramic capacitor. After firing, the external electrode is printed or transferred and fired. Hereinafter, the manufacturing method will be specifically described.

  First, the dielectric ceramic composition powder contained in the dielectric layer paste is prepared, and this is made into a paint to prepare the dielectric layer paste.

  The dielectric layer paste may be an organic paint obtained by kneading a dielectric ceramic composition powder and an organic vehicle, or may be a water-based paint.

  As the dielectric ceramic composition powder, the above-described oxides, mixtures thereof, and composite oxides can be used. In addition, various compounds that become the above-described oxides and composite oxides by firing, such as carbonates and An acid salt, a nitrate, a hydroxide, an organometallic compound, or the like can be appropriately selected and mixed for use. What is necessary is just to determine content of each compound in a dielectric ceramic composition powder so that it may become a composition of the above-mentioned dielectric ceramic composition after baking.

  The particle size of the dielectric ceramic composition powder is usually about 0.1 to 3 [mu] m in average before the coating.

  An organic vehicle is obtained by dissolving a binder in an organic solvent. The binder used for the organic vehicle is not particularly limited, and may be appropriately selected from usual various binders such as ethyl cellulose and polyvinyl butyral. Further, the organic solvent to be used is not particularly limited, and may be appropriately selected from various organic solvents such as terpineol, butyl carbitol, acetone, toluene, and the like, depending on a method to be used such as a printing method or a sheet method.

  Further, when the dielectric layer paste is used as a water-based paint, a water-based vehicle in which a water-soluble binder or a dispersant is dissolved in water and a dielectric material may be kneaded. The water-soluble binder used for the water-based vehicle is not particularly limited, and for example, polyvinyl alcohol, cellulose, water-soluble acrylic resin, or the like may be used.

  The internal electrode layer paste is obtained by kneading the above-mentioned organic vehicle with various conductive metals composed of various dielectric metals and alloys, or various oxides, organometallic compounds, resinates, etc. that become the above-mentioned conductive materials after firing. Prepare.

  The external electrode paste may be prepared in the same manner as the internal electrode layer paste described above.

  There is no restriction | limiting in particular in content of the organic vehicle in each above-mentioned paste, For example, what is necessary is just about 1-5 weight% of binders, for example, about 10-50 weight% of binders. Each paste may contain additives selected from various dispersants, plasticizers, dielectrics, insulators, and the like as necessary. The total content of these is preferably 10% by weight or less.

  When the printing method is used, the dielectric layer paste and the internal electrode layer paste are laminated and printed on a substrate such as PET, cut into a predetermined shape, and then peeled from the substrate to obtain a green chip.

  When the sheet method is used, a dielectric layer paste is used to form a green sheet, the internal electrode layer paste is printed thereon, and these are stacked to form a green chip.

Before firing, the green chip is subjected to binder removal processing. The binder removal treatment may be appropriately determined according to the type of the conductive material in the internal electrode layer paste. However, when a base metal such as Ni or Ni alloy is used as the conductive material, the oxygen partial pressure in the binder removal atmosphere is 10 It is preferable to be ⁻⁴⁵ to 10 ⁵ Pa. When the oxygen partial pressure is less than the above range, the binder removal effect is lowered. If the oxygen partial pressure exceeds the above range, the internal electrode layer tends to oxidize.

As other binder removal conditions, the temperature rising rate is preferably 5 to 300 ° C./hour, more preferably 10 to 100 ° C./hour, and the holding temperature is preferably 180 to 400 ° C., more preferably 200 to 350. The temperature holding time is preferably 0.5 to 24 hours, more preferably 2 to 20 hours. The firing atmosphere is preferably air or a reducing atmosphere, and as an atmosphere gas in the reducing atmosphere, for example, a mixed gas of N ₂ and H ₂ is preferably used after being humidified.

The atmosphere at the time of green chip firing may be appropriately determined according to the type of conductive material in the internal electrode layer paste, but when a base metal such as Ni or Ni alloy is used as the conductive material, the oxygen content in the firing atmosphere The pressure is preferably 10 ⁻⁷ to 10 ⁻³ Pa. When the oxygen partial pressure is less than the above range, the conductive material of the internal electrode layer may be abnormally sintered and may be interrupted. Further, when the oxygen partial pressure exceeds the above range, the internal electrode layer tends to be oxidized.

  Moreover, the holding temperature at the time of baking becomes like this. Preferably it is 1100-1400 degreeC, More preferably, it is 1200-1380 degreeC, More preferably, it is 1260-1360 degreeC. If the holding temperature is lower than the above range, the densification becomes insufficient. If the holding temperature is higher than the above range, the electrode temperature is interrupted due to abnormal sintering of the internal electrode layer, the capacity temperature characteristic deteriorates due to diffusion of the constituent material of the internal electrode layer, and the dielectric Reduction of the body porcelain composition is likely to occur.

As other firing conditions, the rate of temperature rise is preferably 50 to 500 ° C./hour, more preferably 200 to 300 ° C./hour, and the temperature holding time is preferably 0.5 to 8 hours, more preferably 1 to 3 hours. The time and cooling rate are preferably 50 to 500 ° C./hour, more preferably 200 to 300 ° C./hour. Further, the firing atmosphere is preferably a reducing atmosphere, and as the atmosphere gas, for example, a mixed gas of N ₂ and H ₂ is preferably used by humidification.

  When firing in a reducing atmosphere, it is preferable to anneal the capacitor element body. Annealing is a process for re-oxidizing the dielectric layer, and this can significantly increase the IR lifetime, thereby improving the reliability.

  The oxygen partial pressure in the annealing atmosphere is preferably 0.1 Pa or more, particularly 0.1 to 10 Pa. When the oxygen partial pressure is less than the above range, it is difficult to reoxidize the dielectric layer, and when it exceeds the above range, the internal electrode layer tends to be oxidized.

  The holding temperature at the time of annealing is preferably 1100 ° C. or less, particularly 500 to 1100 ° C. When the holding temperature is lower than the above range, the dielectric layer is not sufficiently oxidized, so that the IR is low and the IR life tends to be short. On the other hand, if the holding temperature exceeds the above range, not only the internal electrode layer is oxidized and the capacity is lowered, but the internal electrode layer reacts with the dielectric substrate, the capacity temperature characteristic is deteriorated, the IR is lowered, the IR Life is likely to decrease. In addition, you may comprise annealing only from a temperature rising process and a temperature falling process. That is, the temperature holding time may be zero. In this case, the holding temperature is synonymous with the maximum temperature.

As other annealing conditions, the temperature holding time is preferably 0 to 20 hours, more preferably 2 to 10 hours, and the cooling rate is preferably 50 to 500 ° C./hour, more preferably 100 to 300 ° C./hour. . Further, as the annealing atmosphere gas, for example, humidified N ₂ gas or the like is preferably used.

In the above-described binder removal processing, firing and annealing, for example, a wetter or the like may be used to wet the N ₂ gas, mixed gas, or the like. In this case, the water temperature is preferably about 5 to 75 ° C.

The binder removal treatment, firing and annealing may be performed continuously or independently. When these are performed continuously, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of baking to perform baking, and then cooled to reach the annealing holding temperature. Sometimes it is preferable to perform annealing by changing the atmosphere. On the other hand, when performing these independently, at the time of firing, after raising the temperature under N ₂ gas atmosphere with N ₂ gas or wet to the holding temperature of the binder removal processing, further continuing the heating to change the atmosphere Preferably, after cooling to the holding temperature at the time of annealing, it is preferable to change to the N ₂ gas or humidified N ₂ gas atmosphere again and continue cooling. In annealing, the temperature may be changed to a holding temperature in an N ₂ gas atmosphere, and then the atmosphere may be changed, or the entire annealing process may be a humidified N ₂ gas atmosphere.

The capacitor element body obtained as described above is subjected to end surface polishing, for example, by barrel polishing or sand blasting, and the external electrode paste is printed or transferred and baked to form the external electrode 4. The firing conditions of the external electrode paste are preferably, for example, about 10 minutes to 1 hour at 600 to 800 ° C. in a humidified mixed gas of N ₂ and H ₂ . Then, if necessary, a coating layer is formed on the surface of the external electrode 4 by plating or the like.

  The multilayer ceramic capacitor of the present invention thus manufactured is mounted on a printed circuit board by soldering or the like and used for various electronic devices.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, in the range which does not deviate from the summary of this invention, it can implement in various aspects. .

  For example, in the above-described embodiment, the multilayer ceramic capacitor is exemplified as the electronic component according to the present invention. However, the electronic component according to the present invention is not limited to the multilayer ceramic capacitor, and is composed of a dielectric ceramic composition having the above composition. Any material having a dielectric layer can be used.

  Next, the present invention will be described in more detail with reference to examples that further embody the embodiment of the present invention. However, the present invention is not limited to only these examples.

Example 1
First, as starting materials for producing a dielectric material, a main component material (BaTiO ₃ ) and first to seventh subcomponent materials having an average particle diameter of 0.1 to 1 μm were prepared.

Carbonates (first subcomponent: MgCO ₃ , seventh subcomponent: MnCO ₃ ) are used as raw materials for MgO and MnO, and oxides (second subcomponent: (Ba _0.6 Ca _{0. 4} ) SiO ₃ , third subcomponent: V ₂ O ₅ , fourth subcomponent: Yb ₂ O ₃ , fifth subcomponent: CaZrO ₃ , sixth subcomponent: Y ₂ O ₃ ) were used. In addition, (Ba _0.6 Ca _0.4 ) SiO ₃ as the second subcomponent is wet mixed with BaCO ₃ , CaCO ₃ and SiO ₂ for 16 hours by a ball mill, dried, and fired at 1150 ° C. in the air. Furthermore, it was manufactured by wet grinding with a ball mill for 100 hours. Further, CaZrO ₃ as the fifth subcomponent is manufactured by wet mixing CaCO ₃ and ZrO ₃ with a ball mill for 16 hours, drying, firing in air at 1150 ° C., and further wet pulverizing with a ball mill for 24 hours. did.

In addition, BaTiO _{3 as} a main component is obtained by weighing BaCO ₃ and TiO ₂ respectively, wet-mixing them for about 16 hours using a ball mill, drying them, and then firing them in air at a temperature of 1100 ° C. Similar characteristics were obtained even when a ball mill was used for approximately 16 hours of wet pulverization. Further, the same characteristics were obtained even when BaTiO ₃ as the main component was produced by hydrothermal synthesis powder, oxalate method or the like.

These raw materials are blended so that the composition after firing is as shown in Table 1 with respect to 100 moles of BaTiO _{3 as} a main component, wet mixed by a ball mill for 16 hours, and dried to obtain a dielectric material. It was.

  Next, 100 parts by weight of the obtained dielectric material after drying, 4.8 parts by weight of acrylic resin, 100 parts by weight of ethyl acetate, 6 parts by weight of mineral spirit, and 4 parts by weight of toluene were mixed with a ball mill. A dielectric layer paste was obtained by pasting.

  Next, 100 parts by weight of Ni particles having an average particle size of 0.2 to 0.8 μm, 40 parts by weight of an organic vehicle (8 parts by weight of ethyl cellulose dissolved in 92 parts by weight of butyl carbitol), and 10 parts by weight of butyl carbitol Were kneaded with three rolls to obtain a paste, and an internal electrode layer paste was obtained.

  Next, 100 parts by weight of Cu particles having an average particle size of 0.5 μm, 35 parts by weight of an organic vehicle (8 parts by weight of ethyl cellulose resin dissolved in 92 parts by weight of butyl carbitol) and 7 parts by weight of butyl carbitol were kneaded. To obtain a paste for an external electrode.

  Next, a 4.5 μm-thick green sheet was formed on the PET film using the dielectric layer paste, and the internal electrode layer paste was printed thereon, and then the green sheet was peeled from the PET film. Next, these green sheets and protective green sheets (not printed with internal electrode layer paste) were laminated and pressure-bonded to obtain green chips. The number of sheets having internal electrodes was four.

  Next, the green chip was cut into a predetermined size and subjected to binder removal processing, firing and annealing to obtain a multilayer ceramic fired body.

  The binder removal treatment was performed under the conditions of a temperature rising rate: 30 ° C./hour, a holding temperature: 260 ° C., a holding time: 8 hours, and an air atmosphere.

Firing is performed at a heating rate of 200 ° C./hour, a holding temperature of 1240 ° C., a holding time of 2 hours, a cooling rate of 200 ° C./hour, a humidified N ₂ + H ₂ mixed gas atmosphere (oxygen partial pressure is 10 ⁻⁶ Pa). ).

The annealing was performed under the conditions of a holding temperature: 1000 ° C., a temperature holding time: 2 hours, a cooling rate: 200 ° C./hour, and a humidified N ₂ gas atmosphere (oxygen partial pressure is 10 ⁻² Pa). Note that a wetter with a water temperature of 30 ° C. was used for humidifying the atmospheric gas during firing and annealing.

Next, after polishing the end face of the multilayer ceramic fired body by sand blasting, the external electrode paste is transferred to the end face and fired at 800 ° C. for 10 minutes in a humidified N ₂ + H ₂ atmosphere to form the external electrode. A sample of the multilayer ceramic capacitor having the configuration shown in FIG. 1 was obtained.

  The size of each sample thus obtained is 3.2 mm long × 1.6 mm wide × 0.6 mm high, the number of dielectric layers sandwiched between the internal electrode layers is 4, and the thickness is The thickness was 3.5 μm, and the thickness of the internal electrode layer was 1.2 μm.

  The obtained capacitor sample was evaluated for capacitance-temperature characteristics (Tc), insulation resistance (IR), and relative dielectric constant (ε).

  For the capacity-temperature characteristic (Tc), the capacitance was measured in the temperature range of −55 ° C. to + 175 ° C. for the obtained sample. The capacitance was measured using a digital LCR meter (YHP 4274A) under the conditions of a frequency of 1 kHz and an input signal level of 1 Vrms. Then, the temperature change rate (ΔC / C. Unit:%) of the capacitance at 175 ° C. at which the capacity-temperature characteristic is the worst in these temperature ranges is calculated, and this satisfies ΔC / C = within ± 15%. Investigate whether to do. In addition, regarding the X8R characteristics (−55 to 150 ° C., ΔC / C = within ± 15%) which slightly decreased on the high temperature side to 150 ° C., those satisfying this were evaluated as ◎, and those not satisfying were evaluated as ×.

  Further, the capacity change rate ΔC / C in the temperature range of −55 ° C. to + 175 ° C. for the representative sample 45 (see Table 5) corresponding to the example of the present invention and the representative sample 1 corresponding to the comparative example. Was measured and plotted in FIG. FIG. 2 shows the rate of change based on the capacitance at 25 ° C. As is apparent from FIG. 2, it can be understood that the sample 45 corresponding to the example of the present invention shows a good capacity-temperature characteristic not only at 150 ° C. but also at a higher temperature side (175 ° C.). On the other hand, Sample 1 corresponding to the comparative example shows a good capacity-temperature characteristic up to the high temperature side (150 ° C.) of X8R. It can be understood that / C = ± 15% or less is not satisfied.

The insulation resistance (IR) was measured by using a temperature variable IR measuring instrument, and the insulation resistance IR ₁₇₅ of the obtained sample at 175 ° C. was measured under the conditions of a measurement voltage: 20 V and a voltage application time: 60 s. The evaluation criterion was IR = 10 ⁶ Ω or higher.

  The relative dielectric constant (ε) is obtained under the conditions of a frequency of 1 kHz and an input signal level (measurement voltage) of 1.0 Vrms with a digital LCR meter (YHP 4274A) at a reference temperature of 25 ° C. with respect to the obtained capacitor sample. It was calculated from the capacitance measured in (No unit). The evaluation standard was ε = 1000 or more.

  For the obtained capacitor sample, dielectric loss (tan δ), IR lifetime under DC electric field, DC dielectric breakdown strength, DC bias characteristics (dependence of DC permittivity on dielectric constant), and TC bias are also evaluated. did.

  Dielectric loss (tan δ) was measured with a digital LCR meter (YHP 4274A) at a reference temperature of 25 ° C. and a frequency of 1 kHz and an input signal level (measurement voltage) of 1.0 Vrms with respect to a capacitor sample. . As a result, good results were obtained for all samples of 10% or less.

  The IR life under a direct current electric field was calculated by performing an acceleration test on a capacitor sample at 200 ° C. under an electric field of 10 V / μm, and calculating the time until the insulation resistance was 1 MΩ or less as the life time. As a result, good results were obtained for all samples of 10 hours or more.

  The DC breakdown strength is 100 V / sec. The voltage (DC breakdown voltage VB, unit is V / μm) when a leakage current of 100 mA was detected was measured and the average value was calculated. As a result, good results were obtained for all samples of 100 V / μm or more.

  The DC bias characteristics were plotted by measuring the change in capacitance (ΔC / C) when a DC voltage was gradually applied to each sample at a constant temperature (25 ° C.) with respect to the capacitor sample. As a result, it was confirmed that any sample had a stable DC bias characteristic because the capacitance was not easily reduced even when a high voltage was applied.

  The TC bias is obtained by changing the temperature of the obtained sample from −55 ° C. to 150 ° C. with a bias voltage (DC voltage) of 1 kHz, 1 Vrms, 7.0 V / μm using a digital LCR meter (YHP 4274A). Measurement was performed, and the rate of change in capacitance was calculated and evaluated from a measured value during application of no bias voltage at 25 ° C. The capacitance was measured using an LCR meter under conditions of a frequency of 1 kHz and an input signal level of 1 Vrms. As a result, all the samples were as good as -40%.

  As shown in Table 1, when the ratio (y3) of the third subcomponent is too small (1 mol), the X8R characteristic is satisfied, but the temperature characteristic at 175 ° C. is deteriorated. When the ratio (y3) of the third subcomponent was too large (6.2 mol), the insulation resistance IR was too low to measure the rate of change in capacitance with temperature.

  On the other hand, when the ratio of the third subcomponent (y3) is in an appropriate range, the X8R characteristic is satisfied, the temperature characteristic at 175 ° C. is good, and the value of Mn / V is also appropriate. Thus, it was confirmed that an appropriate IR could be secured.

Example 2
A capacitor sample was prepared in the same manner as in Example 1 except that the type and content of the third subcomponent were changed as shown in Tables 2 to 4, and the same evaluation was performed.

As shown in Tables 2 and ₃ , it can be confirmed that the same effect as V ₂ O _{5 in} Table 1 can be obtained even if the third subcomponent is changed to MoO ₃ and WO ₃ .

As shown in Table 4, even if the third subcomponent is changed to a composite form of V ₂ O ₅ and MoO ₃ , the same effect as that obtained when V ₂ O ₅ is added alone (see Table 1) can be obtained. I can confirm.

Example 3
A capacitor sample was prepared in the same manner as in Example 1 except that the type and content of the seventh subcomponent were changed as shown in Tables 5 to 7, and the same evaluation was performed.

  As shown in Table 5, even if the ratio of the third subcomponent (y3) is in the proper range, the ratio of Mn to V (Mn / V) is too small (0.225) or too large (2.917). ) And the insulation resistance IR became too low to measure the temperature change rate of the capacitance.

  On the other hand, since the ratio of Mn to V (Mn / V) is in an appropriate range, it is possible to secure an appropriate IR and the value of y3 is also appropriate, satisfying the X8R characteristic and at 175 ° C. It was confirmed that the temperature characteristics of were good.

As shown in Table 6, it can be confirmed that even if the seventh subcomponent is changed to Cr ₂ O ₃ , the same effect as MnCO ₃ in Table 5 can be obtained.

As shown in Table 7, it can be confirmed that even if the seventh subcomponent is changed to a composite form of MnCO ₃ and Cr ₂ O ₃ , the same effect as that obtained when MnCO ₃ is added alone (see Table 5) can be obtained. .

Example 4
To sample 4 of Example 1 (see Table 1), except that Al ₂ O ₃ as the eighth subcomponent was further added in the ratio of Table 8 (however, the number of moles relative to 100 moles of the main component), A capacitor sample was produced in the same manner as in Example 1.

  The obtained capacitor sample was evaluated for IR temperature dependency (digit loss) together with the capacitance temperature characteristic (Tc) of Example 1. The results are shown in Table 8.

The IR temperature dependency (digit loss) was evaluated by measuring the insulation resistance IR ₁₇₅ at 175 ° C. and the insulation resistance IR _{25 at} 25 ° C. of the obtained sample, and calculating the digit loss represented by the following formula 1. . The evaluation criteria were good at -3.5 or more.
log (IR ₁₇₅ / IR ₂₅ ) ... Equation 1

  The insulation resistance at each temperature was measured using a temperature variable IR measuring instrument at a measurement voltage of 7.0 V / μm and a voltage application time of 60 s.

As shown in Table 8, even when the 8th subcomponent was added, the temperature change rate of the capacitance at 175 ° C. was not deteriorated, and addition of the 8th subcomponent resulted in an IR loss. It became -3.5 or more, and it has confirmed that IR temperature dependency was improved.
Even changing the eighth subcomponent _{Ge 2 O 2, Ga 2 O} 3, the same effect as the _Al 2 _{O 3} was obtained. Furthermore, changing the composite form of _Al 2 _{O 3} and _Ge 2 _{O 2,} the same effect as when added with _Al 2 _{O 3} alone was obtained.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a graph showing capacity-temperature characteristics of the sample 45 corresponding to the example of the present invention and the sample 1 corresponding to the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 10 ... Capacitor element main body 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode

Claims (12)

A main component comprising barium titanate;
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
A second subcomponent containing silicon oxide as a main component;
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
A fourth subcomponent comprising an oxide of R1, wherein R1 is at least one selected from Sc, Er, Tm, Yb and Lu;
A fifth subcomponent comprising CaZrO ₃ or CaO + ZrO ₂ ;
A dielectric ceramic composition having a seventh subcomponent containing one or both of MnO and Cr ₂ O ₃ ,
The ratio of the third subcomponent with respect to 100 mol of the main component (y3, where the value converted to a metal element) is 1 to 6 mol (excluding 1 mol),
A dielectric ceramic composition in which a ratio of the seventh subcomponent (y7, where a value converted to a metal element) is 0.25 to 2.5 times y3. The ratio (y1, y2, y4, y5) of each subcomponent with respect to 100 moles of the main component is
First subcomponent (y1): 0.1 to 3 mol,
Second subcomponent (y2): 2 to 10 mol,
Fourth subcomponent (y4): 0.5 to 7 mol (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone),
5. The dielectric ceramic composition according to claim 1, wherein the fifth subcomponent (y5) is 5 mol or less (excluding 0 mol). 3. The dielectric ceramic composition according to claim 1, wherein the third subcomponent includes at least V ₂ O ₅ , and the seventh subcomponent includes at least MnO. A main component comprising barium titanate;
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
A second subcomponent containing silicon oxide as a main component;
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
A fourth subcomponent comprising an oxide of R1, wherein R1 is at least one selected from Sc, Er, Tm, Yb and Lu;
A fifth subcomponent comprising CaZrO ₃ or CaO + ZrO ₂ ;
A dielectric ceramic composition having a seventh subcomponent containing one or both of MnO and Cr ₂ O ₃ ,
The ratio (y1 to y5) of each subcomponent with respect to 100 moles of the main component is
First subcomponent (y1): 0.1 to 3 mol,
Second subcomponent (y2): 2 to 10 mol,
3rd subcomponent (y3. However, the value converted into the metal element): 1-6 mol (however, except 1 mol),
Fourth subcomponent (y4): 0.5 to 7 mol (provided that the number of moles of the fourth subcomponent is the ratio of R1 alone),
5th subcomponent (y5): 5 mol or less (however, excluding 0 mol),
A dielectric ceramic composition in which a ratio of the seventh subcomponent (y7, where a value converted to a metal element) is 0.25 to 2.5 times y3. As a sixth subcomponent, it further comprises an oxide of R2 (wherein R2 is at least one selected from Y, Dy, Ho, Tb, Gd and Eu),
The ratio (y6) of the sixth subcomponent is 9 mol or less (excluding 0 mol, where the number of moles of the sixth subcomponent is the ratio of R2 alone) with respect to 100 mol of the main component. Item 5. The dielectric ceramic composition according to any one of Items 1 to 4. The total ratio of the fourth subcomponent and the sixth subcomponent is 13 mol or less (excluding 0 mol) with respect to 100 mol of the main component. However, the number of moles of the fourth subcomponent and the sixth subcomponent is R1 and R2. 6. The dielectric ceramic composition according to claim 5, wherein the dielectric ceramic composition is a single ratio. The second subcomponent is represented by SiO ₂ , MO (where M is at least one element selected from Ba, Ca, Sr and Mg), at least one selected from Li ₂ O and B ₂ O _3. The dielectric ceramic composition according to any one of claims 1 to 6, wherein As an eighth subcomponent, an oxide of A (provided that A is at least one selected from the group of cationic elements having an effective ionic radius of 0.065 nm to 0.085 nm at the time of 6 coordination) Item 8. The dielectric ceramic composition according to any one of Items 1 to 7. The ratio (y8) of the eighth subcomponent is 0 to 4 mol (excluding 0 mol and 4 mol, a value converted to oxide A) with respect to 100 mol of the main component. Dielectric ceramic composition. An electronic component having a dielectric layer composed of a dielectric ceramic composition,
An electronic component, wherein the dielectric ceramic composition comprises the dielectric ceramic composition according to claim 1. A multilayer ceramic capacitor having a capacitor element body in which dielectric layers composed of dielectric ceramic compositions and internal electrode layers are alternately laminated,
A multilayer ceramic capacitor, wherein the dielectric ceramic composition comprises the dielectric ceramic composition according to any one of claims 1 to 9. The multilayer ceramic capacitor according to claim 11, wherein the internal electrode layer is mainly composed of nickel or a nickel alloy.

Images