JP5275918B2 - Multilayer ceramic electronic components - Google Patents

Description

  The present invention relates to a multilayer ceramic electronic component, and more particularly to a multilayer ceramic electronic component having improved withstand voltage characteristics.

  Multilayer ceramic electronic components are widely used as small-sized, high-performance, and high-reliability electronic components, and many of them are used in electrical and electronic devices. In recent years, with the miniaturization and high performance of devices, the demand for further miniaturization, higher performance, and higher reliability of multilayer ceramic electronic components has become increasingly severe.

  Among the multilayer ceramic capacitors as an example of the multilayer ceramic electronic component, there is a medium-high voltage capacitor used under conditions of a high rated voltage. In a capacitor used under such a high voltage, the electric field applied from the outside tends to concentrate near the end of the internal electrode layer, and the voltage load increases. As a result, there has been a problem that the dielectric layer is broken starting from the dielectric layer existing in the vicinity of the end of the internal electrode layer, and the reliability cannot be ensured.

  In order to solve such a problem, Patent Document 1 discloses that the tip portion of the internal electrode is disposed in a high breakdown voltage region having a higher breakdown voltage than other regions, thereby preventing the dielectric layer from being broken and having a breakdown voltage characteristic. A multilayer ceramic capacitor that improves the above is disclosed.

  However, in the multilayer ceramic capacitor disclosed in Patent Document 1, a high withstand voltage region having a low dielectric constant is also disposed between the layers of the internal electrodes. For this reason, there has been a problem that the capacitance cannot be increased and a high capacity cannot be realized as a capacitor. In addition, the green sheet that becomes the dielectric layer after firing needs to be a composite green sheet of a high withstand voltage region and a low withstand voltage region, which causes a problem that the load on the manufacturing process is large.

JP 2004-111608 A

  The present invention has been made in view of such a situation, and an object thereof is to provide a multilayer ceramic electronic component having improved withstand voltage characteristics and high reliability.

In order to achieve the above object, a multilayer ceramic electronic component according to the present invention comprises:
A multilayer ceramic electronic component having an element body in which ceramic layers and internal electrode layers are alternately stacked,
The ceramic layer contains a main component and subcomponents, and with respect to 100 mol of the main component,
Mg oxide as a subcomponent contains 1.0 mol or more in terms of Mg element, and Mn and / or Cr oxide as a subcomponent contains 0.05 mol or more in terms of Mn and / or Cr element And
When the ratio of the number of moles of Mg element to the total number of moles of Mn element and / or Cr element (Mg / (Mn + Cr)) is α, the relationship of 2.5 ≦ α ≦ 50 is satisfied,
The ceramic layer has a thickness of 3 μm or less;
The ceramic layer is composed of a main phase and a segregation phase;
In the laminated surface, the segregation phase, the formed on at least a portion in the vicinity of the peripheral end portion of the internal electrode layers, Ri the segregated phase high phase der insulating properties than said main phase facing the stacking direction ,
The segregation phase includes a complex oxide of Mn and / or Cr and Mg .

  In the present invention, a segregation phase different from the composition of the main phase and the internal electrode layer is formed in the vicinity of the peripheral end of the internal electrode layer. However, this segregation phase is not formed between the internal electrode layers. Since this segregation phase has higher insulation than the main phase existing between the internal electrode layers, the segregation phase is not easily destroyed even if an electric field is concentrated on this segregation phase.

  Therefore, such a segregation phase having a high insulating property is formed in the vicinity of the peripheral end portion of the internal electrode layer, whereby the withstand voltage characteristics as the multilayer ceramic electronic component can be improved.

  In addition, this segregation phase is formed only in the vicinity of the peripheral end portion of the internal electrode layer, and is not formed between the internal electrode layers. Therefore, the characteristic that the ceramic layer (mainly the main phase) existing between the internal electrode layers is not disturbed. Therefore, the withstand voltage characteristic can be improved without impairing the characteristic.

  Since the above complex oxide has high insulating properties, the breakdown voltage characteristics of the multilayer ceramic electronic component can be further improved by including such a complex oxide in the segregation phase.

  By making the content of the oxide of Mg, the oxide of Mn and / or Cr, and the molar ratio of these elements within the above ranges, the segregation phase can be easily formed.

  Preferably, the ceramic layer is a dielectric layer. In the present invention, when the ceramic layer is a dielectric layer, the effect of improving the withstand voltage characteristic is particularly large.

  In the multilayer ceramic electronic component according to the present invention, a segregation phase having higher insulation than the main phase is formed only in the vicinity of the peripheral end portion of the internal electrode layer. Therefore, even if the voltage applied from the outside is concentrated in the vicinity of the end of the internal electrode layer, the segregation phase is not easily destroyed. As a result, the withstand voltage characteristic of the multilayer ceramic electronic component according to the present invention can be improved. In addition, since the segregation phase is not formed between the internal electrode layers, the withstand voltage characteristics can be improved without impeding the characteristics of the ceramic layer sandwiched between the internal electrode layers.

FIG. 1 is a perspective view of a multilayer ceramic capacitor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor shown in FIG. 1 cut along the line II-II. FIG. 3 is a cross-sectional view of the multilayer ceramic capacitor shown in FIG. 1 cut along the line III-III. 4 is a cross-sectional view of the multilayer ceramic capacitor shown in FIG. 1 cut along line IV-IV. FIG. 5A is a schematic cross-sectional view of samples of examples and comparative examples of the present invention cut along a plane perpendicular to a dielectric layer and not including an external electrode. FIG. 5B is a schematic diagram of SEM observation results and EPMA analysis results for the VB portion shown in FIG. 5A. FIG. 5C is a schematic diagram of SEM observation results and EPMA analysis results for the VC portion shown in FIG. 5A.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

Multilayer ceramic capacitor 1
As shown in FIG. 1, a multilayer ceramic capacitor 1 according to an embodiment of the present invention includes a capacitor having a configuration in which dielectric layers 2 (not shown) as ceramic layers and internal electrode layers 3 are alternately stacked. An element body 10 is included. 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 shape of the capacitor element body 10 is not particularly limited, but is usually a rectangular parallelepiped as shown in FIG. 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.

Dielectric layer 2
The dielectric layer 2 is composed of a main phase and a segregation phase 20. In the present embodiment, the main phase and the segregation phase 20 have different compositions, and the main phase is composed of a dielectric ceramic composition. The material constituting the dielectric ceramic composition is not particularly limited, but as a main component, for example, calcium titanate, strontium titanate, barium titanate, or a mixture thereof is preferable. In particular, 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) can be preferably used.

In the present embodiment, the dielectric ceramic composition contains Mg oxide and Mn oxide and / or Cr oxide as subcomponents. That is, in this embodiment, each oxide of Mg, Mn, and Cr is contained in any of the following combinations.
(1) Mg oxide and Mn oxide (2) Mg oxide and Cr oxide (3) Mg oxide, Mn oxide and Cr oxide

  The content of Mg oxide is preferably 0.75 mol or more, more preferably 0.75 to 7.0 mol, further preferably 0.75 to 2 in terms of Mg element with respect to 100 mol of the main component. 0.0 mole. Even if the content of the Mg oxide is too small or too large, the segregation phase described later tends not to be formed.

The content of the Mn oxide and / or Cr oxide is preferably 0.05 mol or more, more preferably 0.05 to 4 in terms of Mn element and / or Cr element with respect to 100 mol of the main component. 0.0 mol, and more preferably 0.05 to 0.5 mol. That is, for example, when the content of Cr oxide is 1.0 mol, the content as Cr ₂ O ₃ is 0.5 mol. Even if the content of Mn oxide and / or Cr oxide is too small or too large, the segregation phase described later tends to be difficult to be formed.

  Further, when the ratio of the number of moles of Mg element to the total number of moles of Mn element and / or Cr element (Mg / (Mn + Cr)) is α, preferably 2.5 ≦ α ≦ 50, more preferably 2.5 ≦ α ≦ 25. Even if α is too small or too large, the segregation phase 20 described later tends to be hardly formed.

Segregation phase 20
The segregation phase 20 is a phase having a different composition from the main phase and the internal electrode layer 3 and having a higher insulating property than the main phase. The segregation phase 20 is not particularly limited as long as it has a higher insulating property than the main phase, but preferably contains a composite oxide of Mg and Mn and / or Cr. The oxide constituting the composite oxide is an oxide used for improving the characteristics of the multilayer ceramic capacitor, and the insulating property of the composite oxide is very high, which has the effect of improving the withstand voltage characteristics. Because it is big.

  The segregation phase 20 is formed at least in the vicinity of the peripheral end portion of the internal electrode layer, and is formed on the entire peripheral end portion surrounded by the dielectric layer 2 (main phase) other than the segregation phase 20. Is preferred. In the present embodiment, as shown in FIG. 2, in the cross section taken along the plane perpendicular to the laminated surface and not including the external electrode 4 (II-II line direction in FIG. 1), in the vicinity of both end portions of the internal electrode The segregation phase 20 is formed on the surface. However, the segregation phase 20 does not exist between the internal electrode layers 3.

  Further, as shown in FIG. 3, in a cross section cut by a plane perpendicular to the laminated surface and including the external electrode 4 (III-III line direction in FIG. 1), segregation occurs in the vicinity of one end of the internal electrode. Phase 20 is formed. The other end of the internal electrode layer 3 is connected to the external electrode 4.

  Further, as shown in FIG. 4, in the cross section cut along the laminated surface including the internal electrode layer 3 (IV-IV line direction in FIG. 1), except for the end (side) connected to the external electrode 4, A segregation phase 20 is formed in the vicinity of the peripheral end portion of the internal electrode layer 3.

  As described above, since the segregation phase 20 is formed in the vicinity of the peripheral end portion of the internal electrode layer 3, even when a voltage is applied from the outside and the electric field is concentrated on the peripheral end portion of the internal electrode layer. The segregated phase 20 has higher insulating properties than the main phase (having a lower dielectric constant than the main phase), and is therefore less likely to be destroyed than the main phase. As a result, the withstand voltage characteristic as a multilayer ceramic capacitor can be improved, and the reliability as a product can be improved.

  Moreover, the segregation phase 20 is not formed between the internal electrode layers 3, and the main phase (dielectric layer 2 other than the segregation phase 20) has a higher dielectric constant than the segregation phase 20. Only) are arranged. Therefore, the withstand voltage characteristic can be improved while realizing the high capacity of the multilayer ceramic capacitor.

  The segregation phase 20 is preferably formed so as to be continuous with the internal electrode layer 3, but does not have to be completely continuous, and there is a gap of about 1 μm between the internal electrode layer 3 and the segregation phase 20. May be present.

  Further, the length of the segregation phase 20 (the length in the extension surface direction of the internal electrode layer 3) is not particularly limited as long as it is the same as the margin portion of the capacitor body 10 or shorter than the margin portion. About 5 μm. When the length of the segregation phase 20 is too short, the effect of improving the withstand voltage characteristic tends to be small. Moreover, when too long, it may become a cause of a structural defect.

  The dielectric ceramic composition according to the present embodiment may further contain other subcomponents according to desired characteristics.

  Specifically, the dielectric ceramic composition according to the present embodiment includes an oxide of R as a subcomponent (where R is Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd). , Tb, Dy, Ho, Er, Tm, Yb and Lu). For example, the oxide of R has an effect of extending the life of the insulation resistance (IR). The content of the oxide of R is preferably 0.05 to 9.0 mol, more preferably 0.05 to 2.0 mol in terms of R element with respect to 100 mol of the main component.

  The dielectric ceramic composition according to the present embodiment preferably contains at least one selected from a V oxide, a Mo oxide, and a W oxide as a subcomponent. These oxides have, for example, the effect of flattening the capacity-temperature characteristics at temperatures above the Curie point and the effect of improving the IR lifetime. The content of these oxides is preferably 0.001 to 0.5 mol, more preferably 0.001 to 0.1 mol, in terms of V element, Mo element and W element, with respect to 100 mol of the main component. It is.

The dielectric ceramic composition according to the present embodiment preferably contains a Si oxide as a subcomponent. The oxide of Si has, for example, an effect as a sintering aid and an effect of improving a defective rate of initial insulation resistance when thinned. The content of the Si oxide is preferably 0.2 to 12.0 mol, more preferably 0.5 to 3.0 mol in terms of Si element with respect to 100 mol of the main component. The form in which the Si oxide is contained is not particularly limited. For example, it may be contained in the form of SiO _{2 or in} the form of a composite oxide such as (Ba, Ca) SiO _3. It may be.

  When the dielectric ceramic composition according to the present embodiment contains the above-mentioned main component and subcomponent, in addition to the effects of the present invention, for example, a multilayer ceramic capacitor satisfying X8R characteristics can be obtained. Alternatively, a multilayer ceramic capacitor that satisfies the X7R characteristics and a multilayer ceramic capacitor that satisfies the B characteristics and the X5R characteristics can be obtained.

  The thickness of the dielectric layer 2 is not particularly limited, but is preferably 5 μm or less per layer, more preferably 3 μm or less, still more preferably 2 μm or less, and particularly preferably 1.5 μm or less. Although the minimum of thickness is not specifically limited, For example, it is about 0.5 micrometer. When the thickness of the dielectric layer is larger than 5 μm per layer, the effect of improving the withstand voltage characteristics due to the presence of the segregation phase tends to be reduced.

  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. The upper limit of the number of stacked layers is not particularly limited, but is about 2000, for example.

Internal electrode layer 3
The conductive material contained in the internal electrode layer 3 is not particularly limited, but a relatively inexpensive 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 3 may be appropriately determined according to the application and the like, but is usually 0.1 to 3 μm, particularly preferably about 0.2 to 2.0 μm.

External electrode 4
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 appropriately determined according to the application and the like, but is usually preferably about 10 to 50 μm.

Manufacturing Method of Multilayer Ceramic Capacitor 1 The multilayer ceramic capacitor 1 of the present embodiment is the same as a conventional multilayer ceramic capacitor. After producing a green chip by a normal printing method or a sheet method using a paste and firing it, It is manufactured by printing or transferring an external electrode and firing. Hereinafter, the manufacturing method will be specifically described.

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

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

As the dielectric material, the above-mentioned main component and subcomponent oxides, mixtures thereof, and composite oxides can be used. In addition, various compounds that become the above oxides or composite oxides by firing, such as carbonic acid, can be used. A salt, an oxalate salt, a nitrate salt, a hydroxide, an organometallic compound, or the like can be selected as appropriate and used in combination. For example, BaTiO ₃ powder may be used as a raw material of barium titanate (BaTiO ₃ ), or BaCO ₃ powder and TiO ₂ powder may be used.

  What is necessary is just to determine content of each compound in a dielectric raw material so that it may become a composition of the above-mentioned dielectric ceramic composition after baking. In the state before forming a paint, the particle size of the dielectric material is usually about 0.1 to 1 μm in average particle size.

Barium titanate (BaTiO ₃ ) powder as a main ingredient is manufactured by various liquid phase methods (eg, oxalate method, hydrothermal synthesis method, alkoxide method, sol-gel method, etc.) in addition to the so-called solid phase method. What was manufactured by various methods, such as a thing, can be used.

  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. 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 according to 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, etc. 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 internal electrode layer paste may contain a common material. The common material is not particularly limited, but preferably has the same composition as the main component.

  Furthermore, in this embodiment, the internal electrode layer paste preferably contains a composite oxide of Mg and Mn and / or Cr or a raw material thereof. When an internal electrode pattern is formed using such an internal electrode layer paste, a segregation phase can be selectively formed at the end portion of the internal electrode layer after firing. Moreover, by doing so, not only the withstand voltage can be improved, but also the IR life can be improved.

  In addition, a multilayer ceramic electronic component in which a segregated phase is formed can be obtained by employing a normal manufacturing method without using a special manufacturing means for forming a segregated phase.

  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 printed and laminated 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 green sheet is formed using a dielectric layer paste, an internal electrode layer paste is printed thereon to form an internal electrode pattern, and these are stacked to form a green chip. .

  Before firing, the green chip is subjected to binder removal processing. As binder removal conditions, the temperature rising rate is preferably 5 to 300 ° C./hour, the holding temperature is preferably 180 to 400 ° C., and the temperature holding time is preferably 0.5 to 24 hours. The firing atmosphere is air or a reducing atmosphere.

The firing of the green chip is preferably performed in a reducing atmosphere. As the atmosphere gas, for example, a mixed gas of N ₂ and H ₂ can be used by humidification. Other conditions are preferably as follows.

  The heating rate is preferably 250 to 450 ° C./hour. The holding temperature at the time of firing is preferably 1300 ° C. or less, more preferably 1200 to 1300 ° C., and the holding time is preferably 0.5 to 8 hours, more preferably 2 to 3 hours. 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 is interrupted due to abnormal sintering of the internal electrode layer, the capacity temperature characteristic is deteriorated due to diffusion of the constituent material of the internal electrode layer, the dielectric Reduction of the body porcelain composition is likely to occur.

The oxygen partial pressure during firing may be appropriately determined according to the type of the 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 ⁻¹⁴ to 10 ⁻¹⁰ MPa. 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. The temperature lowering rate is preferably 50 to 500 ° C./hour.

  After firing in a reducing atmosphere, the capacitor element body is preferably annealed. 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 ⁻⁹ to 10 ⁻⁵ MPa. When the oxygen partial pressure is less than the above range, it is difficult to re-oxidize the dielectric layer, and when it exceeds the above range, oxidation of the internal electrode layer tends to proceed.

  The holding temperature at the time of annealing is preferably 1100 ° C. or less, and particularly preferably 1000 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 4 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 main body obtained as described above is subjected to end face polishing, for example, by barrel polishing or sand blasting, and the external electrode paste is applied and fired to form the external electrode 4. 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 this embodiment manufactured in this way is mounted on a printed circuit board or the like by soldering or the like and used for various electronic devices.

  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 internal electrode layer paste is printed on the green sheet to form the internal electrode pattern, and then laminated. On the other hand, in order to eliminate the step of the internal electrode pattern, a blank paste is used to form a blank pattern that becomes a dielectric layer after firing in a gap portion on the green sheet where the internal electrode pattern is not formed. Also good. By forming a blank pattern by adding an oxide constituting the segregation phase to the blank paste, the oxide contained in the blank paste is formed in the vicinity of the peripheral edge of the internal electrode layer after firing. A segregated phase is obtained.

  In the above-described embodiment, the multilayer ceramic capacitor is exemplified as the multilayer ceramic electronic component according to the present invention. However, the multilayer ceramic electronic component according to the present invention is not limited to the multilayer ceramic capacitor and has the above-described configuration. Any electronic component can be used.

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

Examples 1-7 and Comparative Examples 1-5
First, BaTiO ₃ powder is used as a main component material, and MgCO ₃ , MnO, Y ₂ O ₃ , Yb ₂ O ₃ , Tb ₂ O _3.5 , V ₂ O ₅ , CaZrO ₃ and ( Ba, Ca) SiO ₃ were prepared.

Next, the BaTiO ₃ powder prepared above and the raw material of the accessory component were wet pulverized for 15 hours by a ball mill and dried to obtain a dielectric raw material. In addition, the addition amount of each subcomponent was set so that the content of the subcomponent in the dielectric layer after firing was the amount shown in Table 1 with respect to 100 mol of BaTiO _{3 as} the main component. In addition, MgCO ₃ is contained in the dielectric ceramic composition as MgO after firing.

  Next, the obtained dielectric material: 100 parts by weight, polyvinyl butyral resin: 10 parts by weight, dioctyl phthalate (DOP) as a plasticizer: 5 parts by weight, and alcohol as a solvent: 100 parts by weight with a ball mill The mixture was made into a paste to obtain a dielectric layer paste.

  In addition to the above, Ni particles: 44.6 parts by weight, terpineol: 52 parts by weight, ethyl cellulose: 3 parts by weight, and benzotriazole: 0.4 parts by weight are kneaded with three rolls to obtain a slurry. To prepare an internal electrode layer paste.

  Then, using the dielectric layer paste prepared above, a green sheet was formed on the PET film so that the thickness after drying was 2 μm. Next, the electrode layer was printed in a predetermined pattern using the internal electrode layer paste thereon, and then the sheet was peeled off from the PET film to produce a green sheet having the electrode layer. Next, a plurality of green sheets having electrode layers were laminated and pressure-bonded to obtain a green laminated body, and the green laminated body was cut into a predetermined size to obtain a green chip.

  Next, the obtained green chip was subjected to binder removal treatment, firing and annealing under the following conditions to obtain a multilayer ceramic fired body.

  The binder removal treatment conditions were temperature rising rate: 25 ° C./hour, holding temperature: 260 ° C., temperature holding time: 8 hours, and atmosphere: in the air.

The firing conditions were a temperature increase rate of 200 ° C./hour, a holding temperature of 1200 to 1300 ° C., and a holding time of about 2 hours. The temperature decreasing rate was the same as the temperature increasing rate. The atmospheric gas was a humidified N ₂ + H ₂ mixed gas, and the oxygen partial pressure was 10 ⁻¹² MPa.

The annealing conditions were: temperature rising rate: 200 ° C./hour, holding temperature: 1000 ° C., temperature holding time: 2 hours, temperature falling rate: 200 ° C./hour, atmospheric gas: humidified N ₂ gas (oxygen partial pressure: 10 ⁻⁷ MPa).

  A wetter 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 sandblasting, Cu was applied as an external electrode to obtain a sample of the multilayer ceramic capacitor shown in FIG. The size of the obtained capacitor sample is 3.2 mm × 1.6 mm × 0.6 mm, the thickness of the dielectric layer is 1.5 μm, the thickness of the internal electrode layer is 1.5 μm, and the dielectric sandwiched between the internal electrode layers The number of layers was 10. The samples of Examples 1 to 7 and Comparative Examples 1 to 5 are samples that satisfy the B characteristic and the X5R characteristic.

  For the obtained capacitor sample, the segregation phase was observed and the withstand voltage characteristics were measured by the methods described below.

Observation of segregation phase First, a capacitor sample was cut on a surface perpendicular to the dielectric layer and not including an external electrode. Next, as shown in FIG. 5A, this cut surface was subjected to SEM observation and EPMA analysis on the peripheral edge portion and the central portion of the internal electrode layer, and the segregation phase of the segregation phase was determined from the results of element mapping of Mg element, Mn element and Cr element. The presence or absence was confirmed. The results are shown in Table 1.

Breakdown voltage (withstand voltage)
With respect to the capacitor sample, at a temperature of 25 ° C., the DC voltage was increased at a boosting rate of 100 V / sec. The withstand voltage characteristic of the capacitor sample was evaluated by measuring the withstand voltage with the voltage value (unit: V) when a current of 10 mA was applied, and measuring the withstand voltage. In this example, a withstand voltage of 200 V or higher was considered good. The results are shown in Table 1.

Examples 8 and 9 and Comparative Examples 6 and 7
A multilayer ceramic capacitor sample was prepared in the same manner as in Example 1 except that the content of the subcomponent was changed to the amount shown in Table 1, and the same characteristic evaluation as in Example 1 was performed. The samples of Example 8 and Comparative Example 6 are samples that satisfy the X8R characteristics. The samples of Example 9 and Comparative Example 7 are samples that are preferably used for medium and high pressure. The results are shown in Table 1.

  In the column of “presence / absence of segregation phase” in Table 1, the sample indicated by “◯” is schematically shown in FIG. 5B as a result of EPMA analysis in the vicinity of the peripheral edge of the internal electrode layer. In addition, a segregation phase was observed in the vicinity of the peripheral edge of the internal electrode layer. As a result of performing EPMA analysis on the vicinity of the central portion of the internal electrode layer of this sample, a segregation phase was observed, but the ratio was extremely small and negligible. FIG. 5C schematically shows a case where no segregation phase is formed near the center. In addition, the part shown by the black in FIG. 5B and FIG. 5C is an area | region where each element exists.

From the evaluation table 1, it can be confirmed that the withstand voltage characteristic is improved in the sample in which the segregation phase is observed regardless of the composition of the subcomponent. 5A to 5C, it can be confirmed that the segregation phase is formed only in the vicinity of the peripheral end portion of the internal electrode layer and includes a composite oxide of Mg and Mn and / or Cr. And it can confirm that the segregation phase is formed when content of the oxide of Mg, Mn, and Cr and the number of moles of Mg, Mn, and Cr are in the preferable range of the present invention.

Examples 11-14
A multilayer ceramic capacitor sample was prepared in the same manner as in Examples 1, 2, 13, and 14 except that the content of the subcomponents and the internal electrode layer paste was prepared as follows. In addition to the above characteristic evaluation, the IR life shown below was also evaluated. The results are shown in Table 2.

In addition, the dielectric raw material contains MgO: 0.5 mol, MnO (or Cr ₂ O ₃ ): 0.05 mol, with respect to 100 mol of BaTiO ₃ , in the content of subcomponents in the dielectric layer after firing. The auxiliary component raw materials were weighed and prepared so that Y ₂ O ₃ : 1.0 mol, V ₂ O ₅ : 0.03 mol, and (Ba, Ca) SiO ₃ : 1.0 mol.

In addition, an internal electrode layer paste was prepared by adding 100% by weight of the internal electrode layer paste prepared in Example 1 in an amount such that Mg and Mn are in the ratio shown in Table 2 with respect to 100 mol of BaTiO _3. did. Mg and Mn were added in the form of a composite oxide. The composite oxide of Mg and Mn was produced as follows. First, MgCO ₃ and MnCO ₃ were weighed and mixed by a ball mill so that the ratio of Mg and Mn became a value shown in Table 2. And this mixed powder was heat-processed at 900 degreeC, and the composite oxide of Mg and Mn was obtained. A composite oxide of Mg and Cr was also produced in the same manner.

The IR lifetime was evaluated by holding a DC voltage applied to an IR lifetime capacitor sample at 160 ° C. under an electric field of 10 V / μm and measuring the change in insulation resistance (IR) with time. In this example, the time from the start of application until the insulation resistance became 10 ⁶ Ω or less was defined as the lifetime. Further, the measurement of the IR lifetime was performed on 20 capacitor samples, and the average value was defined as the IR lifetime (average lifetime). In this example, the IR life is preferably 5 hours or longer, and more preferably 10 hours or longer. The results are shown in Table 2.

From the evaluation table 2, after adding Mg and Mn (or Cr) to the internal electrode layer paste, the ratio of Mg and Mn is within the preferred range of the present invention (Examples 11 to 14). It can be confirmed that, in addition to showing the withstand voltage characteristics equivalent to those of Examples 1, 2, 13, and 14, the IR lifetime is also improved.

  This is because the Mg component and Mn (or Cr) component in the paste move to the dielectric layer by firing, and the segregation phase containing the Mg component and Mn (or Cr) component is in the vicinity of the peripheral edge of the internal electrode layer. This is probably because it was formed only in That is, the Mg component and the Mn (or Cr) component that have moved to the dielectric layer suppress the grain growth of the dielectric particles (particles constituting the dielectric layer) existing in the vicinity of the internal electrode layer. As a result, the particle growth of the conductive particles (particles constituting the internal electrode layer) generated along with the growth of the dielectric particles is suppressed, and excessive spheroidization of the conductive particles is prevented.

DESCRIPTION OF SYMBOLS 1 ... Multilayer ceramic capacitor 2 ... Dielectric layer 3 ... Internal electrode layer 4 ... External electrode 10 ... Capacitor element body 20 ... Segregation phase

Claims (4)

A multilayer ceramic electronic component having an element body in which ceramic layers and internal electrode layers are alternately stacked,
The ceramic layer contains a main component and subcomponents, and with respect to 100 mol of the main component,
Mg oxide as a subcomponent contains 1.0 mol or more in terms of Mg element, and Mn and / or Cr oxide as a subcomponent contains 0.05 mol or more in terms of Mn and / or Cr element And
When the ratio of the number of moles of Mg element to the total number of moles of Mn element and / or Cr element (Mg / (Mn + Cr)) is α, the relationship of 2.5 ≦ α ≦ 50 is satisfied,
The ceramic layer has a thickness of 3 μm or less;
The ceramic layer is composed of a main phase and a segregation phase;
In the laminated surface, the segregation phase, the formed on at least a portion in the vicinity of the peripheral end portion of the internal electrode layers, Ri the segregated phase high phase der insulating properties than said main phase facing the stacking direction ,
The multilayer ceramic electronic component , wherein the segregation phase includes a composite oxide of Mn and / or Cr and Mg . The multilayer ceramic electronic component according to claim 1, wherein the Mg oxide is contained in an amount of 1.0 to 3.0 mol in terms of Mg element with respect to 100 mol of the main component. The multilayer ceramic electronic component according to claim 1, wherein the segregation phase is not formed between the internal electrode layers in the stacking direction.   The multilayer ceramic electronic component according to claim 1, wherein the ceramic layer is a dielectric layer.

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