JP2005119912A - Dielectric porcelain composition, and electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric porcelain composition having sufficient insulation resistance even when baked in a neutral or reducing atmosphere, capable of suppressing an IR (initial insulation resistance) fraction defective even when a ceramic capacitor is thin-layered or multi-layered, and also having a high dielectric constant. <P>SOLUTION: The dielectric porcelain composition comprises a main component expressed by the compositional formula of ääBa<SB>(1-x)</SB>Ca<SB>x</SB>}O}<SB>A</SB>äTi<SB>(1-y)</SB>Zr<SB>y</SB>}<SB>B</SB>O<SB>2</SB>, and as sub-components, an oxide of Mn, an oxide of Si, an oxide of at least one kind selected from V and W and oxides of two kinds of rare earth elements, in which the total of the oxides of the two kinds of rare earth elements is 0.2 to 1.2 mol to 100 mol of the main component. A, B, x and y satisfy 0.995≤A/B≤1.020, 0≤x≤0.25, and 0.1≤y≤0.3 in the compositional formula. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  A multilayer ceramic capacitor, which is an example of an electronic component, is obtained by, for example, firing a green chip obtained by alternately stacking ceramic green sheets made of a predetermined dielectric ceramic composition and internal electrode layers of a predetermined pattern and then integrating them. Manufactured. Since the internal electrode layer of the multilayer ceramic capacitor is integrated with the ceramic dielectric by firing, it is necessary to select a material that does not react with the ceramic dielectric. For this reason, as a material constituting the internal electrode layer, conventionally, an expensive noble metal such as platinum or palladium has been inevitably used.

  On the other hand, in order to use an inexpensive base metal (for example, nickel or copper) as a material for the internal electrode, it does not become a semiconductor even when fired in a neutral or reducing atmosphere, that is, has excellent reduction resistance, It is necessary to develop a dielectric ceramic composition having a sufficient dielectric constant and excellent dielectric properties (for example, a small rate of change in capacitance temperature) after firing.

  Various proposals have been made as dielectric ceramic compositions in which a base metal such as nickel or copper can be used as the material of the internal electrode (see, for example, Patent Document 1).

In the BaO-CaO-TiO ₂ -ZrO ₂ based dielectric ceramic composition, the dielectric constant increases, there is a decline in the deterioration and the AC breakdown voltage of the temperature characteristic of the capacitance becomes a problem, In order to solve these problems, a dielectric ceramic composition characterized by containing MgO and Y ₂ O ₃ has been proposed (see, for example, Patent Document 2).

  However, in this document, a single plate ceramic capacitor is studied, and a multilayer capacitor is not studied. Furthermore, since the dielectric ceramic composition contains MgO, there is a problem that the relative permittivity is greatly reduced.

  On the other hand, in recent years, there is a high demand for downsizing of electronic components due to higher density of electronic circuits, and downsizing and increasing capacity of multilayer ceramic capacitors are rapidly progressing. As a result, dielectric layers per layer in multilayer ceramic capacitors have become thinner and dielectric layers have increased in number due to an increase in the number of layers. Dielectrics that can maintain the reliability of capacitors even when they are made thinner and multilayered. There is a need for a body porcelain composition.

  Particularly for miniaturization and large capacity, very high reliability is required for the dielectric ceramic composition. This is because if the dielectric layer is made thinner and multi-layered for miniaturization and capacity increase, if the dielectric ceramic composition has insufficient insulation resistance, an initial insulation resistance failure, that is, an IR failure may occur. It is because the nature becomes high.

JP-A-6-45182 JP 2003-109430 A

  The object of the present invention is to have sufficient insulation resistance even when fired in a neutral or reducing atmosphere, and when used as a dielectric layer of a multilayer ceramic capacitor, the multilayer ceramic capacitor is thinned and multilayered Is to provide a dielectric ceramic composition that can keep the IR defect rate low and has a high relative dielectric constant. Another object of the present invention is to provide an electronic component such as a multilayer ceramic capacitor manufactured using such a dielectric ceramic composition and having improved reliability. In particular, an object of the present invention is to provide an electronic component such as a multilayer ceramic capacitor capable of being thinned, multilayered and miniaturized.

  The inventors of the present invention use a dielectric ceramic composition used as a dielectric layer of an electronic component such as a multilayer ceramic chip capacitor as a dielectric layer of the multilayer ceramic capacitor. As a result of intensive investigations on a dielectric ceramic composition having a high relative dielectric constant even when the number of layers is reduced, two types of subcomponents are used as the dielectric ceramic composition. The inventors have found that the object of the present invention can be achieved by adding rare earth element oxides, and have completed the present invention.

That is, the dielectric ceramic composition according to the present invention is
The main component is a composition formula {{Ba _(1-x) Ca _x } O} _A {Ti _(1-y) Zr _y } _B O _2.
(However, A, B, x, y are 0.995 ≦ A / B ≦ 1.020, 0 ≦ x ≦ 0.25, 0.1 ≦ y ≦ 0.3)
As an auxiliary component, with respect to 100 mol of the main component, the oxide of Mn is 0.03 to 1.70 mol in terms of MnO, the oxide of Si is 0 to 1.00 mol in terms of SiO ₂ , V And a dielectric ceramic composition containing at least one oxide of W and W in an amount of 0.001 to 0.7 mol in terms of V ₂ O ₅ and WO ₃ ,
Two kinds of rare earth oxides (R1 oxide, R2 oxide) are further included as subcomponents, and the total content of the R1 oxide and the R2 oxide is 100 mol of the main component. In addition, it is 0.1 to 1.2 mol in terms of oxide of R1 and oxide of R2.

  In the dielectric ceramic composition according to the present invention, preferably, the R1 oxide is a Y oxide.

  In the dielectric ceramic composition according to the present invention, preferably, the content of the R1 oxide is 0.1 to 0.6 mol in terms of the oxide of R1 with respect to 100 mol of the main component.

  In the dielectric ceramic composition according to the present invention, preferably, the content of the R2 oxide is 0.1 to 0.6 mol in terms of the oxide of R2 with respect to 100 mol of the main component.

  The electronic component according to the present invention has a dielectric layer made of any one of the above dielectric ceramic compositions. Although it does not specifically limit as an electronic component, 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 are illustrated.

  A multilayer ceramic capacitor according to the present invention has a capacitor element body in which dielectric layers composed of the dielectric ceramic composition described above and internal electrode layers are alternately stacked.

  In the multilayer ceramic capacitor according to the present invention, the number of stacked dielectric layers is preferably 20 or more, more preferably 50 or more, and more preferably 100 or more.

  In the multilayer ceramic capacitor according to the present invention, preferably, the dielectric layer has a thickness of 4.5 μm or less, more preferably 3.0 μm or less.

  According to the present invention, even when fired in a neutral or reducing atmosphere, it has a high insulation resistance, and even when a ceramic capacitor is thinned or multilayered, the IR defect rate can be lowered. Thus, a dielectric ceramic composition having a high relative dielectric constant can be provided. In addition, according to the present invention, it is possible to provide an electronic component such as a multilayer ceramic capacitor having a low IR defect rate and a high relative dielectric constant even when it is thinned or multilayered.

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.
FIG. 2 is a graph showing the relationship between the number of moles of an oxide of a rare earth element and the relative dielectric constant in dielectric ceramic compositions according to examples and comparative examples of the present invention,
FIG. 3 is a graph showing the relationship between the number of moles of rare earth element oxides and the IR defect rate in dielectric ceramic compositions according to examples and comparative examples of the present invention.

  As shown in FIG. 1, a multilayer ceramic capacitor 1 according to an embodiment of the present invention includes a capacitor element body 10 having a configuration 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 shape of the capacitor element body 10 is not particularly limited, but is usually a rectangular parallelepiped shape. Moreover, there is no restriction | limiting in particular also in the dimension, What is necessary is just to set it as a suitable dimension according to a use.

  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 dielectric layer 2 contains the dielectric ceramic composition of the present invention.
The dielectric ceramic composition of the present _{invention, {{Ba (1-x} ) Ca x} O} A {Ti (1-y) Zr y} mainly containing a dielectric oxide represented by the composition by B _{O 2} A sub-component that includes a component, an oxide of Mn, an oxide of Si, at least one oxide of V and W, and an oxide of two rare earth elements (an oxide of R1 and an oxide of R2). With ingredients. At this time, the amount of oxygen (O) may be slightly deviated from the stoichiometric composition of the above formula.

  In the above formula, x is 0 or more and 0.25 or less, preferably 0.01 or more and 0.1 or less. Moreover, y is 0.1 or more and 0.3 or less, preferably 0.15 or more and 0.25 or less. A / B is 0.995 or more and 1.020 or less, preferably 1.000 or more and 1.010 or less.

  In this composition, x represents the ratio of Ca. This Ca mainly acts as an element that improves the sintering stability and the insulation resistance value. When x exceeds 0.25, the relative permittivity tends to be low. Therefore, the value of x is preferably in the range of 0 ≦ x ≦ 0.25.

  In the composition formula, y represents the ratio of Zr, and this Zr mainly functions as a shifter that moves the Curie point to the low temperature side. When y is less than 0.1, the dielectric loss tends to increase, and when y exceeds 0.3, the relative permittivity tends to decrease. Therefore, the value of y is preferably in the range of 0.1 ≦ y ≦ 0.3.

  In the composition formula, when A / B is less than 0.995, abnormal grain growth of the dielectric layer tends to occur during firing, and the insulation resistance value tends to decrease, and A / B exceeds 1.020. And the sinterability tends to decrease, making it difficult to obtain a dense sintered body. Therefore, A / B is preferably in the range of 0.995 ≦ A / B ≦ 1.020.

  The oxide of Mn has an effect of promoting sintering, an effect of increasing IR, and an effect of improving the IR lifetime, and is 0.03 to 1.70 in terms of MnO with respect to 100 mol of the main component. Mol, preferably 0.1 to 1.0 mol, and more preferably 0.3 to 0.7 mol. If the Mn oxide content is too small, the added effect tends to be difficult to obtain, and if it is too much, the relative dielectric constant tends to decrease.

The oxide of Si acts as a sintering aid and is 0 to 1.00 mol, preferably 0.4 to 1.0 mol in terms of SiO _{2 with} respect to 100 mol of the main component. When the content of Si oxide is too large, the dielectric constant tends to decrease.

The oxide of V and the oxide of W have an effect of improving the IR lifetime, and at least one oxide of V and W is converted to V ₂ O ₅ and WO _{3 with} respect to 100 mol of the main component. 0.001 to 0.7 mol, preferably 0.01 to 0.2 mol. When the content of the oxide of V and the oxide of W is too small, the added effect tends to be difficult to obtain, and when it is too large, IR tends to be remarkably lowered.

  The feature of the dielectric ceramic composition of the present invention is that the main component and the subcomponents are contained, and two kinds of rare earth element oxides (R1 oxide and R2 oxide) are added in a predetermined amount. It is in the point to add. By adding two kinds of rare earth element oxides, even when fired in a neutral or reducing atmosphere, it has sufficient insulation resistance, and even when ceramic capacitors are thinned and multilayered, IR The defect rate can be lowered and the relative dielectric constant can be increased.

  When rare earth oxides are not included, firing in a neutral or reducing atmosphere causes the dielectric porcelain composition to become a semiconductor, making it impossible to secure sufficient insulation resistance. Becomes difficult. In addition, when a Mg oxide is added to solve this problem, the relative permittivity is lowered.

  Furthermore, when only one kind of rare earth element oxide is added, sufficient insulation resistance can be secured and the relative dielectric constant can be increased. However, when the ceramic capacitor is thinned and multilayered, Even if the amount added is increased, the IR defect rate cannot be kept low.

  The reason why the IR defect rate can be reduced by adding two kinds of rare earth element oxides has not been clarified in detail, but it is better to add two kinds of rare earth element oxides. It is considered that one of the factors is that it becomes easier to dissolve in the main component than when only one kind is added.

  It should be noted that other rare earth element oxides or other subcomponents may be added as long as the object of the present invention can be achieved.

  The two types of rare earth oxides (R1 oxide, R2 oxide), the total content of the R1 oxide and the R2 oxide is 100 moles of the R1 oxide. And 0.1 to 1.2 mol in terms of oxide of R2, preferably 0.2 to 1.0 mol, and more preferably 0.4 to 0.9 mol. If the content of the oxides of the two rare earth elements is too small, the IR defect rate tends to increase, and if it is too large, the relative permittivity tends to decrease.

  The oxide of R1 is preferably a Y oxide. That is, it is preferable that one of the two types of rare earth oxides is an oxide of Y. By making one of the two kinds of rare earth element oxides into Y oxides, it contains two kinds of rare earth element oxides. This is because the IR defect rate can be kept low and the relative dielectric constant can be further improved.

  The content of the R1 oxide is preferably 0.1 to 0.6 mol, more preferably 0.1 to 0.45 mol in terms of the oxide of R1 with respect to 100 mol of the main component. is there. If the content of the R1 oxide is too small, the IR defect rate tends to be high, and if it is too large, the relative dielectric constant tends to decrease.

  The oxide of R2 may be anything as long as it is an oxide of a rare earth element other than Y, but more preferably an oxide of each element of Eu, Tb, Dy, Ho, Er, Tm, or Yb. When the oxide of R2 is an oxide of such an element, the effect of the present invention is particularly improved.

  The content of the R2 oxide is 0.1 to 0.6 mol, preferably 0.1 to 0.45 mol in terms of the oxide of R2 with respect to 100 mol of the main component. When the content of the oxide of R2 is too small, the IR defect rate tends to increase, and when it is too large, the relative permittivity tends to decrease.

  Note 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.

  The thickness of the dielectric layer 2 is not particularly limited, but is preferably 7 μm or less per layer, more preferably 4.5 μm or less, and particularly preferably 3 μm or less. Although the minimum of thickness is not specifically limited, For example, it is about 0.5 micrometer.

  The number of laminated dielectric layers 2 is not particularly limited, but is preferably 20 or more, more preferably 50 or more, and particularly preferably 100 or more.

  In the present embodiment, even when the thickness of the dielectric layer 2 is reduced to 4.5 μm or less and the number of laminations is 20 or more, particularly 100 or more, the IR defect rate is low and the lamination has a high relative dielectric constant. A ceramic capacitor can be obtained.

  The average crystal grain size of the dielectric particles contained in the dielectric layer 2 is not particularly limited, and may be appropriately determined from the range of 1.0 to 5.0 μm, for example, according to the thickness of the dielectric layer 2 and the like. The thickness is preferably 2.0 to 3.0 μm. By reducing the average grain size, the relative permittivity tends to decrease, but the HALT can be improved.

  The conductive material contained in the internal electrode layer 3 is not particularly limited, but 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.

  The conductive material contained in the 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 4 may be determined as appropriate according to the application and the like, but is usually preferably about 10 to 50 μm.

  In the multilayer ceramic capacitor using the dielectric ceramic composition of the present invention, as in the conventional multilayer ceramic capacitor, a green chip is produced by a normal printing method or sheet method using a paste, and this is fired, and then externally It is manufactured by printing or transferring an electrode and firing. 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 1 [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 and alloys as described above, 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 ⁻⁹ to 10 ⁻⁴ 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 1200-1300 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 10 ⁻³ Pa or more, particularly preferably 10 ^{−2 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. Note that annealing may be composed of only a temperature raising process and a temperature lowering 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 or mixed gas. 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.

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.

  According to the present invention, in a dielectric ceramic composition having a specific composition, a specific amount of two rare earth element oxides (R1 oxide and R2 oxide) are added as subcomponents. Even when the thickness of the dielectric layer is reduced and the number of laminated dielectric layers is increased, the IR defect rate can be kept low, and the performance is further improved while ensuring a high relative dielectric constant and reliability. be able to.

  As mentioned above, although embodiment of this invention has been described, this invention is not limited to the embodiment mentioned above at all, and can be variously modified within the range which does not deviate from the summary of this invention.

  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.

  Hereinafter, although this invention is demonstrated based on a more detailed Example, this invention is not limited to these Examples.

Example 1
As a starting material, a main component composed of a dielectric oxide having a composition represented by {{Ba _(1-x) Ca _x } O} _A {Ti _(1-y) Zr _y } _B O ₂ produced by sol-gel synthesis Was used. The symbols A, B, x, y indicating the composition ratio in the formula indicating the main component are
A / B = 1.005,
x = 0.01,
The relationship was y = 0.20.
The average particle size of the dielectric oxide was 0.5 μm.

Also, the auxiliary components MnO, SiO ₂ , V ₂ O ₅ , WO ₃ , R1 oxide, R2 oxide, and MgO were wet pulverized in a ball mill for 16 hours in the molar ratios shown in Tables 1 and 2, respectively. The mixture was calcined in the atmosphere at 900 ° C. for 3 hours, and then wet pulverized with a ball mill for 20 hours for pulverization to obtain an additive of an auxiliary component.

  Then, the main component and the subcomponent were wet pulverized with a ball mill for 16 hours and dried to obtain dielectric materials of sample numbers 1 to 21 shown in Tables 1 and 2.

  Using each of these dielectric materials of sample numbers 1 to 21, 100 parts by weight of dielectric material, 4.8 parts by weight of acrylic resin, 10 parts by weight of toluene, 70 parts by weight of ethyl acetate, and 6 parts by weight of mineral spirits. Part and 4 parts by weight of acetone were mixed with a ball mill and made into a paste to obtain a dielectric layer paste.

  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 It knead | mixed with 3 rolls and was made into the paste and obtained the paste for internal electrode layers.

  Using the obtained dielectric layer paste, a green sheet was formed on a PET film. After the internal electrode paste was printed thereon, the 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.

Next, the green chip was cut into a predetermined size and subjected to binder removal processing, firing and annealing under the following conditions to obtain a multilayer ceramic fired body. The binder removal treatment conditions were temperature rising rate: 25.0 ° C./hour, holding temperature: 260 ° C., temperature holding time: 8 hours, atmosphere: in air. Firing conditions were: temperature rising rate: 200 ° C./hour, holding temperature: 1250 ° C., temperature holding time: 2 hours, cooling rate: 200 ° C./hour, atmospheric gas: humidified N ₂ + H ₂ mixed gas (oxygen partial pressure: 10 ⁻⁶ Pa). The annealing conditions were as follows: temperature rising rate: 200 ° C./hour, holding temperature: 1050 ° C., temperature holding time: 2 hours, cooling rate: 200 ° C./hour, atmospheric gas: humidified N ₂ gas (oxygen partial pressure: 10 ⁻¹ Pa). Note that a wetter with a water temperature of 20 ° C. was used for humidifying the atmospheric gas during firing and annealing.

  Next, after polishing the end face of the obtained multilayer ceramic fired body by sand blasting, In-Ga was applied as an external electrode to obtain samples 1 to 21 of the multilayer ceramic capacitor shown in FIG.

  The size of the obtained capacitor sample was 3.2 mm × 1.6 mm × 0.6 mm, the number of dielectric layers sandwiched between internal electrode layers was 100, and the thickness of the dielectric layers per one layer (interlayer thickness) ) Was 4.5 μm, and the thickness of the internal electrode layer was 1.2 μm. Further, when the average crystal grain size in the dielectric layer of each sample was examined, it was 2.5 μm. The following characteristics were evaluated for each sample.

For a sample of relative permittivity (ε _r ), dielectric loss (tan δ), insulation resistance (IR), and CR product capacitor, at a reference temperature of 20 ° C., a digital LCR meter (YHP 4274A), frequency 120 Hz, input Capacitance C and dielectric loss tan δ were measured under the condition of a signal level (measurement voltage) of 0.625 Vrms / μm. Then, the relative dielectric constant (no unit) was calculated from the obtained capacitance. Thereafter, the insulation resistance IR after applying DC 20V to the capacitor sample for 60 seconds at 20 ° C. was measured using an insulation resistance meter (R8340A manufactured by Advantest Corporation). The CR product is represented by the product of capacitance (C, μF) and insulation resistance (IR, MΩ). A larger CR product is preferable.

The relative dielectric constant ε _r is an important characteristic for producing a small and high dielectric constant capacitor. In the present example, the value of the relative dielectric constant ε _r was calculated as an average value of values measured using the number of capacitor samples n = 10. The relative dielectric constant is preferably as large as possible.

In this example, the value of the dielectric loss tan δ was calculated as the average value of the values measured using n = 10 capacitor samples. The smaller tan δ is, the better. The results are shown in Tables 1 and 2. In Tables 1 and 2, in the values of insulation resistance (IR), “mE + n” means “m × 10 ^{+ n} ”.

Applying 20V DC voltage for 1 minute to a sample of an IR defect rate capacitor, measuring the insulation resistance, taking a sample with an insulation resistance value of 1.0 × 10 ⁶ or less as a defective product, the rate of occurrence of defective products In%. The smaller this value, the lower the IR defect rate and the more non-defective products. The results are shown in Tables 1 and 2.

Breakdown voltage (VB)
A DC voltage was applied to the capacitor sample at a heating rate of 100 V / sec. And a leakage current of 100 mA was detected, or a voltage at the time of destruction of the element (breakdown voltage, unit: V / μm) was measured. In this example, the breakdown voltage was calculated as an average value of values measured using 10 capacitor samples. The higher the breakdown voltage, the better. The results are shown in Tables 1 and 2.

Evaluation 1
Table 1 summarizes the composition and characteristics of capacitor samples in which the total content of rare earth element oxides (R1 + R2) is set to a constant amount of 0.60 mol with respect to 100 mol of the main component.

  As shown in Table 1, Samples 1 to 7 of this example in which R1 is Y and R2 is a rare earth element other than Y have a high relative dielectric constant and a low IR defect rate, and are good. It has been found. It was also confirmed that the effects of the present invention can be obtained even when various rare earth elements such as Eu, Tb, Dy, Ho, Er, Tm, and Yb are used as the element added as R2.

  On the other hand, the total content (R1 + R2) of the rare earth element oxide is 0.60 mol, which is the same as the samples 1 to 7 in the examples, but a comparison in which only the oxide of Y is added as the rare earth element oxide. Sample 9 of the example had a good relative dielectric constant, but the IR defect rate was as high as 50%, and it was found that the reliability as a capacitor was low. From this result, it was confirmed that it was necessary to add not only one kind of rare earth element oxide but also two kinds of oxides.

  As for Comparative Samples 10 and 11 in which Mg oxide was added in addition to the rare earth element, the IR defect rate was a good result of 0%, but the relative dielectric constant was a low value. In comparison, it was found that the performance was inferior. From this result, the sample of this example can achieve an IR defect rate as low as that in the case where the Mg oxide used previously is added, and compared with the case where the Mg oxide is added. It was confirmed that it has a high relative dielectric constant.

  The sample 8 of the example in which Dy was added as R1 and Ho was added as R2 had relatively good results in both the relative permittivity and the IR defect rate, but the relative permittivity and IR of the samples 1 to 7 in the example The result was slightly inferior to the defective rate. From this result, it was confirmed that R1 is preferably Y.

Evaluation 2
Table 2 summarizes the composition and characteristics of capacitor samples in which the total content (R1 + R2) of rare earth element oxides was changed. 2 and 3 show the total content of rare earth oxides (R1 + R2) and the ratio of the sample of the example (R1 = Y, R2 = Ho) and the sample of the comparative example (without R1 = Y, R2). The relationship between the dielectric constant (FIG. 2) and the total content of rare earth oxides (R1 + R2) and the IR defect rate are shown (FIG. 3).

  From Table 2, for the samples 4 and 12 to 19 of the examples and comparative examples in which the content of the oxide of Y and the content of the oxide of Ho were changed, the total content of the rare earth oxides (R1 + R2) ) Increased, the relative dielectric constant decreased, and the IR defect rate tended to decrease to a certain content (0.90 mol in this example) and increase again. This tendency is also apparent from the results of FIGS. 2 and 3 in which specific data in Table 2 is graphed.

  Further, the sample 12 of the comparative example in which the total content (R1 + R2) of the rare earth element oxide was 0.05 mol had a high IR defect rate of 45%, and the rare earth element oxide content. In the sample 19 of the comparative example in which the total (R1 + R2) was 1.5 mol, the relative dielectric constant was as low as 7700, and the IR defect rate was as high as 35%. From this result, it is desirable that the total content (R1 + R2) of rare earth element oxides is 0.1 to 1.2 mol, preferably 0.2 to 1. It was confirmed that the amount was 0 mol, and more preferably 0.4 to 0.9 mol.

  Further, as shown in Table 2, it was confirmed that the same tendency was observed for Samples 5, 7, 20 and 21 of Examples in which R1 was Y and R2 was Er or Yb.

  As shown in FIG. 2, the sample of the example and the sample of the comparative example to which only the oxide of Y is added have almost the same relative dielectric constant as long as the rare earth element oxide content is about the same. It was confirmed that it was comparable. However, as shown in FIG. 3, when the rare earth oxide content is within the scope of the present invention, only the sample of the example containing two kinds of rare earth oxides and the Y oxide were used. It was confirmed that there was a great difference in the IR defect rate from the added comparative sample. From this result, when only one kind of rare earth element oxide was added, the IR defect rate could not be kept low even if the amount added was increased. It was confirmed that it was necessary to add two kinds of oxides.

Example 2
Dielectric porcelain compositions similar to Samples 4 and 9 prepared in Example 1 were used as dielectric layers, and samples with different numbers of dielectric layers and samples with different thicknesses of dielectric layers were prepared. Table 3 shows the relationship between the number and thickness of the dielectric layers of the capacitor produced, the relative dielectric constant, and the IR defect rate.

  From Table 3, in the sample of the example containing two kinds of rare earth oxides, when the thickness of the dielectric layer is 4.5 μm, the IR defect rate is low regardless of the number of laminated dielectric layers. As a result. On the other hand, in the sample of the comparative example containing only one kind of rare earth oxide, the IR defect rate tends to deteriorate as the number of laminated dielectric layers increases. In any case, the IR defect rate is 30 It became a high result with more than%.

  Further, as is clear from Table 3, it was confirmed that the effect of the present invention was remarkably exhibited as the number of dielectric layers was increased.

  Similarly, when the number of dielectric layers is 100 and the thickness of the dielectric layer is further reduced to 3.0 μm, the comparative sample has an IR defect rate of 80%, which is a very high value. However, in the sample of the example, it was possible to keep it as low as 25%. From this result, when the dielectric ceramic composition of the present invention is used as a dielectric layer of a multilayer ceramic capacitor, the IR defect rate is reduced even when the dielectric layer is further thinned, for example, 3.0 μm. It was confirmed that a highly reliable multilayer ceramic capacitor can be 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 the relationship between the number of moles of oxides of rare earth elements and the relative dielectric constant in the dielectric ceramic compositions according to the examples and comparative examples of the present invention. FIG. 3 is a graph showing the relationship between the number of moles of rare earth element oxides and the IR defect rate in dielectric ceramic compositions according to examples and comparative examples of the present invention.

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 (8)

The main component is a composition formula {{Ba _(1-x) Ca _x } O} _A {Ti _(1-y) Zr _y } _B O _2.
(However, A, B, x, y are 0.995 ≦ A / B ≦ 1.020, 0 ≦ x ≦ 0.25, 0.1 ≦ y ≦ 0.3)
As an auxiliary component, with respect to 100 mol of the main component, the oxide of Mn is 0.03 to 1.70 mol in terms of MnO, the oxide of Si is 0 to 1.00 mol in terms of SiO ₂ , V And a dielectric ceramic composition containing at least one oxide of W and W in an amount of 0.001 to 0.7 mol in terms of V ₂ O ₅ and WO ₃ ,
Two kinds of rare earth oxides (R1 oxide, R2 oxide) are further included as subcomponents, and the total content of the R1 oxide and the R2 oxide is 100 mol of the main component. The dielectric ceramic composition is characterized by being 0.1 to 1.2 mol in terms of the oxide of R1 and the oxide of R2.   The dielectric ceramic composition according to claim 1, wherein the oxide of R1 is an oxide of Y.   3. The dielectric ceramic according to claim 1, wherein the content of the oxide of R1 is 0.1 to 0.6 mol in terms of the oxide of R1 with respect to 100 mol of the main component. Composition.   The content of the oxide of R2 is 0.1 to 0.6 mol in terms of oxide of R2 with respect to 100 mol of the main component, according to any one of claims 1 to 3. Dielectric ceramic composition.   The electronic component which has a dielectric material layer comprised with the dielectric material ceramic composition in any one of Claims 1-4.   A multilayer ceramic capacitor having a capacitor element body in which dielectric layers composed of the dielectric ceramic composition according to any one of claims 1 to 4 and internal electrode layers are alternately laminated.   The multilayer ceramic capacitor according to claim 6, wherein the number of laminated dielectric layers is 20 or more.   The multilayer ceramic capacitor according to claim 6 or 7, wherein the dielectric layer has a thickness of 4.5 µm or less.

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