JP4696891B2 - Electronic component, dielectric ceramic composition and method for producing the same - 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, a method for manufacturing the same, and an electronic component having 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, printing internal electrodes having a predetermined pattern on a ceramic green sheet made of a predetermined dielectric ceramic composition, alternately stacking a plurality of them, and then integrating them. The green chip is manufactured by simultaneous firing. 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.

  However, in recent years, dielectric ceramic compositions that can use inexpensive base metals such as nickel and copper have been developed, and a significant cost reduction has been realized.

  In recent years, there has been a high demand for downsizing of electronic components due to higher density of electronic circuits, and downsizing and increase in capacity of multilayer ceramic capacitors are rapidly progressing. In order to increase the size and capacity of a multilayer ceramic capacitor, generally, a method of thinning a dielectric layer or a method of increasing the relative dielectric constant of a dielectric ceramic composition contained in the dielectric layer is taken. ing. However, when the dielectric layer is thinned, the electric field applied to the dielectric layer becomes stronger when a DC voltage is applied, so that the change in relative permittivity with time, that is, the change in capacitance with time, becomes extremely large. .

In order to improve the time-dependent change of capacity under a direct current electric field, a method of using dielectric particles having a small average crystal grain size as dielectric particles contained in the dielectric layer has been proposed (for example, patents). Reference 1). This Patent Document 1 discloses a dielectric ceramic composition having a specific composition and having an average crystal grain size of dielectric particles of 0.45 μm or less. However, since the dielectric ceramic composition described in this document has a relative dielectric constant that is too low, it has been difficult to cope with downsizing and large capacity.
JP-A-8-124785

  The present invention has been made in view of such circumstances, and improves the relative dielectric constant without deteriorating other electrical characteristics (for example, temperature characteristics of capacitance, insulation resistance, accelerated lifetime of insulation resistance, dielectric loss). It is an object of the present invention to provide a dielectric ceramic composition capable of satisfying the requirements and a manufacturing method thereof. Another object of the present invention is to provide an electronic component such as a multilayer ceramic capacitor having a dielectric layer composed of such a dielectric ceramic composition.

In order to achieve the above object, a method for producing a dielectric ceramic composition according to the present invention comprises:
A main component comprising barium titanate;
Oxide of R (wherein, R is Y, La, Ce, Pr, Nd, at least one Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, is selected from Yb, and Lu) consisting A method for producing a dielectric ceramic composition having a fourth subcomponent,
Preparing a reacted raw material in which the raw material of the main component and a part of the raw material of the fourth subcomponent to be contained in the dielectric ceramic composition are reacted in advance;
Adding the remaining raw material of the fourth subcomponent to be contained in the dielectric ceramic composition to the reacted raw material,
The fourth subcomponent that is reacted in advance with the raw material of the main component is 0.01 to 0.2 mol in terms of R with respect to 100 mol of the main component .

In the present invention, by causing the raw material of the main component and a part of the raw material of the fourth subcomponent to react in advance, the fourth subcomponent is present at least inside (center part) of the main component. Can do. Therefore, it is possible to improve the relative dielectric constant without deteriorating other electrical characteristics (for example, temperature characteristics of capacitance, insulation resistance, accelerated lifetime of insulation resistance, dielectric loss).

In the present invention, preferably, the raw material of the main component and a part of the raw material of the fourth subcomponent are dissolved in advance. By solid solution, the fourth subcomponent can be uniformly dissolved in the main component, and the electrical characteristics can be further improved.

  In the present invention, the reaction includes a method for creating a state in which the fourth subcomponent exists in the inside (center portion) of the main component, using concepts including solid solution, coating, and the like.

In the present invention, the raw material of the main component and the raw material of the fourth subcomponent to be reacted in advance are not all of the fourth subcomponent to be contained in the dielectric ceramic composition, but a part thereof. . Then, it is preferable that the remaining raw material of the fourth subcomponent is added to the obtained reacted material, calcined as necessary, and then fired. By doing in this way, the effect of this invention can be improved.

  In the present invention, the content of the fourth subcomponent in the finally obtained dielectric ceramic composition is preferably 0.1 to 10 mol in terms of R with respect to 100 mol of the main component, More preferably 0.2 to 6 mol.

  In the present invention, the temperature characteristic of the capacitance can be improved by setting the content of the fourth subcomponent contained in the dielectric ceramic composition within the above range. If the content of the fourth subcomponent is too small, the effect of adding the fourth subcomponent cannot be obtained, and the temperature characteristics of the capacitance tend to deteriorate. On the other hand, if the content is too large, the sintering is performed. Sex tends to get worse.

  Alternatively, in the present invention, the ratio of the fourth subcomponent that is reacted in advance with the raw material of the main component is, in terms of R, finally contained in the dielectric ceramic composition. It is preferably 0 to 50 mol% (however, 0 and 50 are not included), more preferably 0 to 25 mol% (however, 0 is not included) with respect to 100 mol% of the total amount of components. .

  When the amount of the raw material of the main component and the raw material of the fourth subcomponent to be reacted in advance is too large, the crystal grain size of the sintered body obtained after firing becomes too large, and the temperature characteristics are deteriorated or the insulating material is insulated. Resistance (IR) tends to decrease.

In the present invention, preferably, the dielectric ceramic composition is
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
_Second subcomponent mainly containing SiO ₂ and containing at least one selected from MO (wherein M is at least one selected from Mg, Ca, Ba and Sr), Li ₂ O and B ₂ O ₃ When,
A third subcomponent including at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ,
The ratio of each subcomponent to 100 moles of the main component,
1st subcomponent: 0.1-5 mol,
Second subcomponent: 0.1-12 mol,
Third subcomponent: 0 to 0.3 mol (excluding 0),
And

In the present invention, preferably, the dielectric ceramic composition further includes a fifth subcomponent including at least one selected from MnO and Cr ₂ O ₃ ,
The ratio of the 5th subcomponent with respect to 100 mol of said main components shall be 0.05-1.0 mol.

  In the present invention, by including the first to third subcomponents (more preferably, the fifth subcomponent) together with the fourth subcomponent, the temperature characteristics of the capacitance can be improved, In particular, the X7R characteristic of the EIA standard (−55 to 125 ° C., ΔC = within ± 15%) can be satisfied. In addition, although it does not specifically limit about the addition time of the said 1st-3rd, 5th subcomponent, The said 1st-3rd, 5th subcomponent is the raw material of the said main component, and the raw material of the said 4th subcomponent. It is preferable to add at least a part of the above to the reacted material after the reaction.

  In the present invention, a raw material having an average particle size of preferably 0.05 to 0.5 [mu] m, more preferably 0.1 to 0.4 [mu] m is used as the main component. By using the raw material of the main component whose average particle size is in the above range, the average crystal particle size of the sintered dielectric particles can be refined, preferably 0.1 to 0.3 μm, It is possible to reduce the change with time of the relative dielectric constant.

The dielectric ceramic composition further obtained in the present invention, a dielectric ceramic composition produced by the method according to any one of the above.

Electronic components more obtained in the invention has a dielectric layer composed of a dielectric ceramic composition described above. 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.

According to the present invention, since the raw material of the main component and a part of the raw material of the fourth subcomponent are reacted in advance, other electrical characteristics (for example, temperature characteristics of capacitance, insulation resistance, acceleration of insulation resistance) life, dielectric loss) without deteriorating the manufacturing method of the dielectric constant capable dielectric ceramic composition improves the can provide. Furthermore, according to the present invention, it is possible to provide an electronic component such as a multilayer ceramic capacitor having a dielectric layer made of such a dielectric ceramic composition.

  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.
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 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.
Dielectric layer 2

  The dielectric layer 2 contains a dielectric ceramic composition.

In this embodiment, the dielectric ceramic composition is represented by a composition formula Ba _m TiO _{2 + m} , _m in the composition formula is 0.995 ≦ m ≦ 1.010, and the ratio of Ba and Ti is A main component containing barium titanate satisfying 0.995 ≦ Ba / Ti ≦ 1.010 and an oxide of R (where R is Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb) , Dy, Ho, Er, Tm, Yb and Lu), and a fourth subcomponent and other subcomponents.

  The fourth subcomponent is a subcomponent containing an oxide of R. The R element of the oxide of R is at least one selected from R, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Among these, Y, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu are preferable, and Y, Tb, and Yb are more preferable.

  The fourth subcomponent has the effect of improving the IR accelerated life characteristics. The content of the fourth subcomponent is preferably 0.1 to 10 mol in terms of R, more preferably 0.2 to 6 mol. If the content is too small, the effect of adding the fourth subcomponent cannot be obtained, and the capacity-temperature characteristics are deteriorated. On the other hand, if the content is too large, the sinterability tends to deteriorate. As will be described in detail later, the manufacturing method of the present embodiment employs a step of reacting at least a part of the fourth subcomponent raw material with the main component raw material in advance.

  In the present embodiment, it is preferable that the following first to third and fifth subcomponents are further contained as subcomponents other than the fourth subcomponent including the R oxide.

That is, a first subcomponent containing at least one selected from MgO, CaO, BaO and SrO;
_Second subcomponent mainly containing SiO ₂ and containing at least one selected from MO (wherein M is at least one selected from Mg, Ca, Ba and Sr), Li ₂ O and B ₂ O ₃ When,
A third subcomponent comprising at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ;
It is preferable to further contain a fifth subcomponent including at least one selected from MnO and Cr ₂ O ₃ .

The ratio of each subcomponent to the main component is 100 mol of the main component in terms of each oxide.
1st subcomponent: 0.1-5 mol,
Second subcomponent: 0.1-12 mol,
Third subcomponent: 0 to 0.3 mol (excluding 0),
Fifth subcomponent: 0.05 to 1.0 mol, preferably
First subcomponent: 0.2-4 mol,
Second subcomponent: 1 to 6 mol,
Third subcomponent: 0 to 0.25 mol (excluding 0),
5th subcomponent: It is 0.05-0.4 mol.

  In the present embodiment, the dielectric ceramic composition contains the first to third and fifth subcomponents in addition to the fourth subcomponent containing the oxide of R, so that the temperature characteristics of the capacitance can be obtained. Preferably, the X7R characteristic of the EIA standard (−55 to 125 ° C., ΔC = within ± 15%) can be satisfied.

  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 reasons for limiting the contents of the subcomponents are as follows.

  If the content of the first subcomponent (MgO, CaO, BaO, and SrO) is too small, the capacity-temperature change rate becomes large. On the other hand, when there is too much content, while sinterability will deteriorate, it exists in the tendency for a high temperature load life to deteriorate. The composition ratio of each oxide in the first subcomponent is arbitrary.

The second subcomponent contains SiO ₂ as a main component and is selected from MO (where M is at least one selected from Mg, Ca, Ba and Sr), Li ₂ O and B ₂ O _3. Contains at least one. This second subcomponent mainly acts as a sintering aid. MO (where M is at least one selected from Mg, Ca, Ba and Sr) is also included in the first subcomponent, but is a composite oxide with SiO ₂ and represented by the composition formula M _x SiO _{2 + x} . The melting point can be lowered by using the compound to be made. And since melting | fusing point can be made low, the reactivity with respect to a main component can be improved. For example, when BaO and CaO are used as the MO, the composite oxide is preferably a compound represented by a composition formula (Ba, Ca) _x SiO _{2 + x} . _X in the composition formula (Ba, Ca) _x SiO _{2 +} x is preferably 0.8 to 1.2, and more preferably 0.9 to 1.1. When x is too small, that is, when SiO ₂ is too much, it reacts with the main component Ba _m TiO _{2 + m} and deteriorates 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.

The third subcomponent (V ₂ O ₅ , MoO ₃ and WO ₃ ) exhibits the effect of flattening the capacity-temperature characteristics at the Curie temperature or higher and the effect of improving the high temperature load life. If the content of the third subcomponent is too small, such an effect becomes insufficient. On the other hand, when there is too much content, IR will fall remarkably. The constituent ratio of each oxide in the third subcomponent is arbitrary.

The fifth subcomponent (MnO and Cr ₂ O ₃ ) shifts the Curie temperature to the high temperature side, flattens the capacitance-temperature characteristics, improves the insulation resistance (IR), improves the breakdown voltage, and lowers the firing temperature. It has effects such as.

  The average crystal grain size of the dielectric particles contained in the dielectric ceramic composition is not particularly limited, but is preferably 0.1 to 0.3 μm. If the average crystal grain size is too small, the relative permittivity tends to be low, and if it is too large, the change in relative permittivity with time tends to be large. The average crystal grain size of the dielectric particles can be measured, for example, from a SEM image of the dielectric particles by a code method in which the average particle size is measured assuming that the shape of the dielectric particles is a sphere.

  The thickness of the dielectric layer 2 is not particularly limited, but is preferably 4.5 μm or less per layer, more preferably 3.5 μm or less, and even more preferably 3.0 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. 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

  The multilayer ceramic capacitor of this embodiment is similar to the conventional multilayer ceramic capacitor, in which a green chip is produced by a normal printing method or sheet method using a paste, and after firing this, an external electrode is printed or transferred. Manufactured by firing. Hereinafter, the manufacturing method will be specifically described.

  First, a dielectric ceramic composition powder contained in the dielectric layer paste is prepared.

  In the present embodiment, the dielectric ceramic composition powder is prepared as follows. First, the raw material of the main component and a part of the raw material of the fourth subcomponent (a raw material corresponding to a part of the fourth subcomponent to be contained in the dielectric ceramic composition) are reacted in advance. , Preferably in solid solution, to obtain a reacted raw material. Next, the remaining raw material of the fourth subcomponent (the remaining raw material among the fourth subcomponents constituting the dielectric ceramic composition) and the first to third and fifth subcomponents are added to the reacted raw material. The dielectric ceramic composition powder is prepared by adding the component raw materials and calcining as necessary.

As the raw material of the main component, the above Ba _m TiO _{2 + m} powder or a powder of a compound that becomes Ba _m TiO _{2 + m} by firing can be used, and the average particle size of the main component raw material is preferably 0.05 to 0 0.5 μm, more preferably 0.1 to 0.4 μm. If the average particle size of the raw material of the main component is too large, the average crystal particle size of the sintered dielectric particles becomes too large, and the temperature characteristics tend to deteriorate or the insulation resistance (IR) tends to decrease. It is in. On the other hand, if the average particle size is too small, the solid solution of the oxide of R in the main component material tends to be non-uniform. In this embodiment, the average particle diameter means a volume-based cumulative 50% diameter (D50 diameter), and can be measured by a method using light scattering such as a laser diffraction method.

  As the raw material of the fourth subcomponent that is reacted in advance with the main component raw material, the above-mentioned oxide of R or various compounds that become an oxide of R upon firing can be used. As an R oxide or a compound that becomes an R oxide by firing, a powdery raw material having an average particle diameter of about 0.01 to 0.1 μm, a sol-like raw material exemplified below, or the like can be used.

  The sol-shaped raw material is not particularly limited, and examples thereof include hydroxide sol and oxide sol. The sol particle size of the sol-like raw material is usually about 1 to 100 nm, and the solvent is water, alcohols such as methanol and ethanol, aromatic solvents such as xylene and toluene, and ketones such as methyl ethyl ketone. Organic solvents such as are exemplified.

  Although it does not specifically limit as a compound used as the oxide of R by the said baking, R alkoxide, R inorganic acid salt, etc. are illustrated.

The R alkoxide is a compound of an alcohol and an R element, and specifically refers to a compound in which hydrogen of the hydroxyl group of the alcohol is substituted with an R element. The alkoxide R, but are not limited to, the general formula _{C n H 2n + 1 OR (} n is an integer from 1 to 9) various compounds represented by can be used, for _{example, CH 3 OR, C 2 H} 5 OR, _{n-C 3} H 7 _OR, etc. _{i-C 3 H} 7 OR can be mentioned.

  The inorganic acid salt of R is not particularly limited, and examples thereof include chlorides, nitrates, phosphates and sulfates. The inorganic acid salt of R is often in a hydrated state, and is usually used in a state dissolved in water or a water-soluble organic solvent.

  The raw material of the fourth subcomponent that is reacted in advance with the raw material of the main component is preferably 0 to 0.5 mol (however, 0 is not included) in terms of R with respect to 100 mol of the main component. Preferably it is 0.01-0.2 mol.

  Or the ratio of the raw material of the 4th subcomponent made to react beforehand is 0-50 with respect to 100 mol% of total amounts of the 4th subcomponent which will be finally contained in a dielectric ceramic composition in R conversion. It is preferable to make it mol% (however, 0 and 50 are not included), more preferably 0 to 25 mol% (however, 0 is not included), more preferably 0 to 15 mol% (however, 0 is not included). ).

  If the amount of the fourth subcomponent raw material to be reacted in advance with the main component raw material is too large, the crystal grain size of the sintered body obtained after firing becomes too large, the temperature characteristics deteriorate, and the insulation resistance (IR ) Tends to decrease.

  As a method of previously reacting the raw material of the main component and a part of the raw material of the fourth subcomponent to obtain a reacted raw material, a solvent or the like is used for the main component raw material and the fourth subcomponent raw material. And mixing, evaporating the solvent and calcining, and adding a precipitant to the mixed solution to precipitate the fourth subcomponent on the main component and calcining. In addition, the temperature at the time of pre-baking becomes like this. Preferably it is about 500-700 degreeC.

  Next, in the obtained reacted raw material, the remaining fourth subcomponent raw material (remaining raw material among the fourth subcomponents constituting the dielectric ceramic composition), the first to third, 5 Subcomponent raw materials are added, and then mixed and calcined as necessary to obtain a dielectric ceramic composition powder. As the raw material of the remaining fourth subcomponent, the first to third and fifth subcomponents, various oxides and mixtures thereof, composite oxides, and various oxides that become the oxides and composite oxides described above by firing. Compounds can be used.

  Next, a dielectric layer paste is manufactured using the obtained dielectric ceramic composition powder. 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.

  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 made 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. As the binder removal conditions, the temperature rising rate is preferably 5 to 300 ° C./hour, more preferably 10 to 100 ° C./hour, the holding temperature is preferably 180 to 400 ° C., more preferably 200 to 300 ° C., and the temperature holding time. Is preferably 0.5 to 24 hours, more preferably 5 to 20 hours. The binder removal atmosphere is preferably in the air.

Next, the green chip subjected to the binder removal process is fired. 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 1000-1400 degreeC, More preferably, it is 1100-1350 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 is interrupted due to abnormal sintering of the internal electrode layer, the capacity-temperature characteristic is deteriorated due to diffusion of the internal electrode layer constituent material, Reduction of the body porcelain composition is likely to occur.

As other firing conditions, the rate of temperature rise is preferably 100 to 900 ° C./hour, more preferably 200 to 900 ° 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 1200 ° C. or less, particularly 500 to 1200 ° 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 high temperature load life is likely to be shortened. On the other hand, when 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 high temperature The load life is likely to decrease.

As other annealing conditions, the rate of temperature rise is preferably 100 to 900 ° C./hour, more preferably 200 to 900 ° C./hour, and the temperature holding time is preferably 0.5 to 12 hours, more preferably 1 to 10 hours. The time and cooling rate are preferably 50 to 600 ° 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.

  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

First, a main component material (BaTiO ₃ ) having an average particle size of 0.35 μm and a Y ₂ O ₃ powder were prepared as a fourth subcomponent material. Next, the prepared BaTiO ₃ powder and Y ₂ O ₃ powder were wet mixed and pulverized by a ball mill to form a slurry. The slurry was dried, calcined and pulverized to obtain a reacted raw material. The calcining conditions were as follows: temperature increase rate: 200 ° C./hour, holding temperature: 500 ° C., temperature holding time: 2 hours, atmosphere: air. The amount of Y ₂ O ₃ added was 0.02 mol in terms of Y atom (the same applies to the examples, comparative examples and reference examples in the present specification) with respect to 100 mol of the main component. That is, it was 0.01 mol in terms of Y ₂ O ₃ .

Next, the first to fifth subcomponents shown below are added to the obtained reacted raw material, and the mixture is wet-mixed and pulverized by a ball mill to form a slurry. The slurry is dried, calcined and pulverized. Thus, a dielectric ceramic composition powder was obtained. In addition, the addition amount of each subcomponent is the addition amount in terms of each oxide with respect to 100 mol of the main component (however, Y ₂ O ₃ is the addition amount in terms of Y atoms).
MgO (first subcomponent): 1.2 mol (Ba, Ca) SiO ₃
(Second subcomponent): 0.75 mol V ₂ O ₅ (Third subcomponent): 0.03 mol Y ₂ O ₃ (Fourth subcomponent): 0.38 mol MnO (Fifth subcomponent): 0 .2 mole

  100 parts by weight of the dielectric ceramic composition powder obtained above, 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 are mixed by a ball mill. Thus, a dielectric layer paste was obtained.

  Next, 44.6 parts by weight of Ni particles, 52 parts by weight of terpineol, 3 parts by weight of ethyl cellulose, and 0.4 parts by weight of benzotriazole are kneaded with three rolls to form a slurry for an internal electrode layer paste. Obtained.

  Using these pastes, the multilayer ceramic chip capacitor 1 shown in FIG. 1 was manufactured as follows.

  First, a green sheet was formed on a PET film using the obtained dielectric layer paste. 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: 32.5 ° C./hour, holding temperature: 260 ° C., temperature holding time: 8 hours, and atmosphere: in the air.

Firing conditions were: temperature rising rate: 200 ° C./hour, holding temperature: 1260 to 1280 ° C., temperature holding time: 2 hours, cooling rate: 200 ° C./hour, atmospheric gas: humidified N ₂ + H ₂ mixed gas (oxygen content) Pressure: 10 ⁻⁷ 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: 1.01 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 sandblasting, In—Ga was applied as an external electrode, and a multilayer ceramic capacitor sample of Example 1 shown in FIG. 1 was obtained.

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 4, and the thickness of the dielectric layers per layer (interlayers) Thickness) was 4.5 μm, and the thickness of the internal electrode layer was 1.2 μm. Next, for the obtained capacitor sample, the average crystal grain size of dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR accelerated lifetime were obtained by the following method Was evaluated. Moreover, about the said reacted material, the distribution degree of Y element was measured by XPS measurement.
Average crystal grain size of dielectric particles

As a method for measuring the average particle size of the dielectric particles, first, the obtained capacitor sample was cut along a plane perpendicular to the internal electrode, and the cut surface was polished. Then, the polished surface was subjected to chemical etching, then observed with a scanning electron microscope (SEM), and calculated by assuming that the shape of the dielectric particles was a sphere by the code method. The results are shown in Table 1.
Dielectric constant ε

A capacitor sample was measured at a reference temperature of 20 ° C. using a digital LCR meter (YHP4274A manufactured by Yokogawa Electric Corporation) at a frequency of 120 Hz and an input signal level (measurement voltage) of 0.5 Vrms / μm. The capacity C was measured. The relative dielectric constant (no unit) was calculated from the obtained capacitance, the dielectric thickness of the multilayer ceramic capacitor, and the overlapping area of the internal electrodes. A higher dielectric constant is preferable. The results are shown in Table 1.
Dielectric loss tan δ

Dielectric loss with respect to a capacitor sample under the conditions of a frequency of 120 Hz and an input signal level (measurement voltage) of 0.5 Vrms / μm with a digital LCR meter (YHP4274A manufactured by Yokogawa Electric Corporation) at a reference temperature of 20 ° Tan δ was measured. The smaller the dielectric loss, the better. The results are shown in Table 1.
Insulation resistance IR

The insulation resistance IR after applying a DC voltage of 4 V / μm to the capacitor sample for 1 minute at 20 ° C. was measured using an insulation resistance meter (advantest R8340A) on the capacitor sample. The insulation resistance IR is preferably as large as possible. The results are shown in Table 1.
CR product

The CR product was measured by determining the product of the capacitance C (unit: μF) measured above and the insulation resistance IR (unit: MΩ). A larger CR product is preferable. The results are shown in Table 1.
Capacitance temperature characteristics

The capacitance at −55 to 125 ° C. was measured for the capacitor sample, the capacitance change rate ΔC was calculated, and it was evaluated whether or not the X7R characteristic of the EIA standard was satisfied. That is, it was evaluated whether the change rate ΔC was within ± 15% at −55 to 125 ° C. The results are shown in Table 1. In Table 1, a sample satisfying the X7R characteristic was indicated as “◯”, and a sample not satisfied was indicated as “x”.
IR accelerated life

The capacitor sample was subjected to an acceleration test at 180 ° C. under an electric field of 20 V / μm, and the time until the insulation resistance IR became 10 ⁸ Ω or less (unit: time) was calculated. A longer IR accelerated lifetime is preferred. The results are shown in Table 1.
Measurement of the distribution of Y atoms in the reacted raw material

For BaTiO ₃ powder and reacted material obtained by pre-reacting a _Y 2 _{O 3} powder by XPS measurement, the surface depth direction of Ba, Ti, the distribution of each element of Y was measured. As a result of XPS measurement, each element of Ba, Ti, and Y is distributed at almost the same concentration from near the surface to the inside of the reacted raw material, and it is confirmed that the solid solution reaction proceeds uniformly. did it.
Examples 2-4

  When producing the dielectric ceramic composition powder, a dielectric ceramic composition powder was obtained in the same manner as in Example 1 except that the following was performed, and capacitor samples of Examples 2 to 4 were obtained.

That is, in Examples 2 to 4, first, the amount of the main component raw material (BaTiO ₃ ) and Y ₂ O ₃ to be reacted in advance is 0.05 mol (Example 2) and 0, respectively, unlike Example 1. The reacted raw material was obtained as .10 mol (Example 3) and 0.15 mol (Example 4). The amount of Y ₂ O ₃ added (post-added) to the obtained reacted raw material is 0.35 mol (Example 2) and 0.30 mol (Example 2), unlike Example 1. Example 3) and 0.25 mol (Example 4).

For each obtained capacitor sample, in the same manner as in Example 1, the average crystal grain size of the dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR acceleration The life was evaluated. The results are shown in Table 1.
Comparative Example 1

  When producing the dielectric ceramic composition powder, the dielectric ceramic composition powder was obtained in the same manner as in Example 1 except that the following was performed, and a capacitor sample of Comparative Example 1 was obtained.

That is, in Comparative Example 1, the main component material (BaTiO ₃ ) and Y ₂ O ₃ are directly mixed without previously reacting the main component material and the first to fifth subcomponent materials, By pulverizing, a dielectric ceramic composition powder was obtained. In Comparative Example 1, the amount of Y ₂ O ₃ added was 0.40 mol.
Comparative Example 2

  When producing the dielectric ceramic composition powder, the dielectric ceramic composition powder was obtained in the same manner as in Example 1 except that the following was performed, and a capacitor sample of Comparative Example 2 was obtained.

That is, in Comparative Example 2, first, the reacted raw material was obtained by setting the amount of the main component raw material (BaTiO ₃ ) and Y ₂ O ₃ to be reacted in advance to 0.25 mol unlike Example 1. Unlike Example 1, the amount of Y ₂ O ₃ added (post-added) to the obtained reacted raw material was 0.15 mol.

For the obtained capacitor sample, in the same manner as in Example 1, the average crystal grain size of the dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR accelerated lifetime Was evaluated. The results are shown in Table 1.
Reference example 1

  A dielectric ceramic composition powder was obtained in the same manner as in Example 1 except that the dielectric ceramic composition powder was prepared as follows, and a capacitor sample of Reference Example 1 was obtained.

That is, in Reference Example 1, first, the reacted raw material was obtained by setting the amount of the main component raw material (BaTiO ₃ ) and Y ₂ O ₃ reacted in advance to 0.40 mol unlike Example 1. In Reference Example 1, unlike Example 1, a dielectric ceramic composition powder was obtained without adding Y ₂ O ₃ as the fourth subcomponent to the obtained reacted material.

  For the obtained capacitor sample, in the same manner as in Example 1, the average crystal grain size of the dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR accelerated lifetime Was evaluated. The results are shown in Table 1.

Evaluation 1

Table 1 shows the average crystal grain size, relative dielectric constant ε, dielectric loss tan δ, insulation resistance IR, CR product, and capacitance temperature of the dielectric particles of Examples 1 to 4, Comparative Examples 1 and 2 and Reference Example 1. Properties and IR accelerated lifetime are shown. In Table 1, “mE + n” of the insulation resistance IR means “m × 10 ^{+ n} ”.

From Table 1, the main component and a part of Y ₂ O ₃ were reacted in advance to obtain a reacted raw material, and then the remaining Y ₂ O ₃ was added to this reacted raw material. In any of the capacitor samples, the relative dielectric constant can be as high as 4000 or more, and other electrical characteristics (dielectric loss tan δ, insulation resistance IR, CR product, temperature characteristics of capacitance and IR accelerated life) are also available. It was confirmed to be good.

On the other hand, in Comparative Example 1 in which the main component and Y ₂ O ₃ were not reacted in advance, the relative dielectric constant was as low as 3400, and it was confirmed that it was difficult to cope with downsizing and large capacity.

Further, in Reference Example 1 in which the amount of Y ₂ O ₃ reacted in advance with the main component was 0.40 mol, and then Y ₂ O ₃ was not added to the obtained reacted raw material, The average crystal grain size of the dielectric particles became as large as 0.78 μm, resulting in inferior dielectric loss, insulation resistance, capacitance temperature characteristics and IR accelerated lifetime.

From the above results, by comparing Examples 1 to 4 with Comparative Examples 1 and 2, the main component and a part of the fourth subcomponent (Y ₂ O ₃ ) were reacted in advance to obtain other electric It was confirmed that the dielectric constant could be increased while maintaining the characteristics (dielectric loss tan δ, insulation resistance IR, CR product, capacitance temperature characteristics and IR accelerated life) well. Further, by comparing Examples 1 to 4 and Reference Example 1 to react the main component and part of the fourth subcomponent (Y ₂ O ₃ ) in advance to produce a reacted raw material, It is preferable that the amount of the fourth subcomponent (Y ₂ O ₃ ) be within the preferable range of the present invention described above, and the obtained reacted material further includes the remaining fourth subcomponent (Y It was confirmed that it was preferable to add ₂ O ₃ ).
Examples 5 to 8, Comparative Example 3, Reference Example 2

Except that Tb ₂ O ₃ was used instead of Y ₂ O ₃ as a raw material for the fourth subcomponent to be reacted in advance with the main component raw material, in the same manner as in Examples 1 to 4, Comparative Example 2, and Reference Example 1, Capacitor samples of Examples 5 to 8, Comparative Example 3, and Reference Example 2 were manufactured. That is, in Examples 5 to 8, Comparative Example 3, and Reference Example 2, Tb ₂ O ₃ is used as the fourth subcomponent to be reacted in advance (pre-addition) and added to the reacted raw material (post-addition). Y ₂ O ₃ was used as a minor component. For each obtained capacitor sample, in the same manner as in Example 1, the average crystal grain size of the dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR acceleration The life was evaluated. The results are shown in Table 2.

Evaluation 2

Table 2 shows the average crystal grain size, dielectric constant ε, dielectric loss tan δ, insulation resistance IR, CR product, capacitance temperature characteristics of the dielectric particles of Examples 5 to 8, Comparative Example 3, and Reference Example 2 and IR accelerated lifetime is shown. Note that the amount of Tb ₂ O ₃ added was expressed in terms of Tb atoms in the same manner as Y ₂ O ₃ .

From Table 2, it was confirmed that the same tendency was obtained even when Tb ₂ O ₃ was used instead of Y ₂ O ₃ as the fourth subcomponent to be reacted in advance with the main component raw material.
Examples 9-12, Comparative Example 4, Reference Example 3

Except that Yb ₂ O ₃ was used instead of Y ₂ O ₃ as a raw material for the fourth subcomponent to be reacted in advance with the main component raw material, in the same manner as in Examples 1 to 4, Comparative Example 2, and Reference Example 1, Capacitor samples of Examples 9 to 12, Comparative Example 4, and Reference Example 3 were produced. That is, in Examples 9 to 12, Comparative Example 4, and Reference Example 3, Yb ₂ O ₃ is used as the fourth subcomponent to be reacted in advance (pre-addition) and added to the reacted raw material (post-addition). Y ₂ O ₃ was used as a minor component. For each obtained capacitor sample, in the same manner as in Example 1, the average crystal grain size of the dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR acceleration The life was evaluated. The results are shown in Table 3.

Evaluation 3

Table 3 shows the average crystal grain size, relative dielectric constant ε, dielectric loss tan δ, insulation resistance IR, CR product, capacitance temperature characteristics of Examples 9 to 12, Comparative Example 4, and Reference Example 3 and IR accelerated lifetime is shown. Note that the amount of Yb ₂ O ₃ added was expressed in terms of Yb atoms in the same manner as Y ₂ O ₃ .

From Table 3, it was confirmed that the same tendency was obtained even when Yb ₂ O ₃ was used instead of Y ₂ O ₃ as the fourth subcomponent to be reacted in advance with the main component raw material.
Examples 13-16

Example 2 except that Dy ₂ O ₃ , Ho ₂ O ₃ , Gd ₂ O ₃ , Eu ₂ O ₃ was used instead of Y ₂ O ₃ as a raw material for the fourth subcomponent to be reacted in advance with the main component raw material. In the same manner, capacitor samples of Examples 13 to 16 were manufactured. That is, in Example 13, Dy ₂ O ₃ is used as the fourth subcomponent to be reacted in advance (pre-addition), and in Example 14, Ho ₂ O _{3 is used} as the fourth subcomponent to be reacted in advance (pre-addition). In Example 15, Gd ₂ O ₃ is used as a fourth subcomponent that is pre-reacted (pre-addition), and in Example 16, Eu ₂ is used as the fourth sub-component that is pre-reacted (pre-addition). O ₃ was used. In all cases of Examples 13 to 16, Y ₂ O ₃ was used as the fourth subcomponent added to the reacted raw material (post-addition). For each obtained capacitor sample, in the same manner as in Example 1, the average crystal grain size of the dielectric particles, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR acceleration The life was evaluated. The results are shown in Table 4.

Evaluation 4

Table 4 shows the average crystal grain size, the relative dielectric constant ε, the dielectric loss tan δ, the insulation resistance IR, the CR product, the temperature characteristics of the capacitance, and the IR accelerated lifetime of the dielectric particles of Examples 13 to 16. _The addition amount of _{Dy 2 O 3, Ho 2 O} 3, Gd 2 O 3, Eu 2 O 3 _, as well as Y 2 _{O 3,} expressed in the respective terms of atom.

From Table 4, the same results as in the case of Y ₂ O ₃ were obtained even when the above-mentioned rare earth oxide was used instead of Y ₂ O ₃ as the fourth subcomponent to be reacted in advance.

FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment 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 (7)

A main component comprising barium titanate;
An oxide of R (wherein R is at least one selected from Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) A method for producing a dielectric ceramic composition having a fourth subcomponent,
Preparing a reacted raw material in which the raw material of the main component and a part of the raw material of the fourth subcomponent to be contained in the dielectric ceramic composition are reacted in advance;
Adding the remaining raw material of the fourth subcomponent to be contained in the dielectric ceramic composition to the reacted raw material,
The dielectric ceramic composition characterized in that the fourth subcomponent that is reacted in advance with the raw material of the main component is 0.01 to 0.2 mol in terms of R with respect to 100 mol of the main component. Manufacturing method. 2. The method for producing a dielectric ceramic composition according to claim 1, wherein the raw material of the main component and a part of the raw material of the fourth subcomponent are previously dissolved, and the reacted raw material is used.   The content of the fourth subcomponent in the finally obtained dielectric ceramic composition is 0.1 to 10 mol in terms of R with respect to 100 mol of the main component. A method for producing the dielectric ceramic composition as described.   The ratio of the fourth subcomponent that is reacted in advance with the raw material of the main component is, in terms of R, a total amount of 100 mol% of the fourth subcomponent that is finally contained in the dielectric ceramic composition. The method for producing a dielectric ceramic composition according to claim 1, wherein the content is 0 to 50 mol% (however, 0 and 50 are not included). The dielectric ceramic composition is:
A first subcomponent comprising at least one selected from MgO, CaO, BaO and SrO;
_Second subcomponent mainly containing SiO ₂ and containing at least one selected from MO (wherein M is at least one selected from Mg, Ca, Ba and Sr), Li ₂ O and B ₂ O ₃ When,
A third subcomponent including at least one selected from V ₂ O ₅ , MoO ₃ and WO ₃ ,
The ratio of each subcomponent to 100 moles of the main component,
1st subcomponent: 0.1-5 mol,
Second subcomponent: 0.1-12 mol,
Third subcomponent: 0 to 0.3 mol (excluding 0),
A method for producing a dielectric ceramic composition according to any one of claims 1 to 4. The dielectric ceramic composition further includes a fifth subcomponent including at least one selected from MnO and Cr ₂ O ₃ ,
The method for producing a dielectric ceramic composition according to claim 5, wherein a ratio of the fifth subcomponent to 100 mol of the main component is 0.05 to 1.0 mol.   The method for producing a dielectric ceramic composition according to claim 1, wherein a raw material having an average particle diameter of 0.05 to 0.5 μm is used as the main component raw material.

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