JP2002343669A - Laminated ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high reliability laminated ceramic electronic component, such as a laminated ceramic capacitor that can improve acquisition capacitance per unit volume, and can have large capacity, even if it is miniaturized. SOLUTION: In this laminated ceramic electronic component (1) having dielectric and internal electrode layers 2 and 3, the internal electrode layer 3 includes a conductive material particle 3a that ranges in parallel with the dielectric layer 2 for arranging, the conductive material particle 3a has first average- particle diameter (R1), in parallel with the dielectric layer 2 and second average- particle diameter (R2) vertical to the dielectric layer 2, and ratio (R1/R2) of the first average-particle diameter (R1) to the second one (R2) is at least 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic electronic component such as a multilayer ceramic capacitor in which a reduction in an obtained capacitance per unit volume is improved.

[0002]

2. Description of the Related Art The obtained electrostatic capacitance of a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component has a relationship of the following equation (1): "C = [epsilon] _{0. [} epsilon] _r * nx * (S / d)". Here, in the formula (1), C: capacitance (F), ε ₀ : permittivity of vacuum, ε _r : relative permittivity of a dielectric material, n: number of layers, S: effective area, d: dielectric Thickness.

[0003] Therefore, in order to increase the acquired electrostatic capacitance of the capacitor, decreasing the dielectric thickness d, to increase the specific dielectric constant epsilon _r of the dielectric material increases the effective area S, the dielectric layer Any method of increasing the number n is conceivable. However, there is a limit in increasing the effective area in order to obtain a large capacity with a small size. Therefore, a method of increasing the relative dielectric constant or reducing the thickness of the dielectric is generally employed. Thinning of the dielectric thickness is limited to 5 μm for both 10 μm due to problems such as thickness variation.
Although it has been said that, recently, the development of manufacturing technology has led to the development of thin-layer products that have exceeded their limits.

On the other hand, since the internal electrodes of the multilayer ceramic capacitor are integrated with the dielectric material by firing, it is necessary to select a material that does not react with the dielectric material. Conventionally, noble metals such as Pt and Pd have been used, but since these noble metals are expensive, they have caused the cost of the multilayer ceramic capacitor to be high. But,
In recent years, it has become possible to use an inexpensive base metal (such as Ni) as the internal electrode, thereby achieving a significant cost reduction.

[0005]

However, the internal electrode mainly composed of a base metal such as Ni tends to become thicker and cut off as the sintering of the dielectric material progresses.
For this reason, there have arisen a problem that the thickness direction of the multilayer ceramic capacitor expands as the thickness of the internal electrode expands, and a problem that the acquired electrostatic capacity of the capacitor is reduced due to interruption of the internal electrode.

Japanese Patent Application Laid-Open No. 2000-269066 discloses a multilayer ceramic capacitor in which conductive material particles constituting the internal electrodes of the multilayer ceramic capacitor are formed one by one between a pair of dielectric layers. I have. In this publication, it is described that by employing such a configuration, stress between the internal electrode and the dielectric layer at the time of firing can be reduced, and the occurrence of cracks and delamination inside the capacitor body can be prevented. . However, this publication does not refer to what kind of characteristics of the capacitor the average particle size of the conductive material particles affects, and this is a future subject.

An object of the present invention is to provide a multilayer ceramic electronic component, such as a multilayer ceramic capacitor, which can improve the obtained capacitance per unit volume, has a large capacity even when downsized, and has high reliability. .

[0008]

In order to achieve the above object, a multilayer ceramic electronic component according to the present invention is a multilayer ceramic electronic component having a dielectric layer and an internal electrode layer, wherein the internal electrode layer is A conductive material particle arranged in a direction parallel to the dielectric layer, wherein the conductive material particle has a first average particle size (R1) in a direction parallel to the dielectric layer.
And a second average particle size (R2) in a direction perpendicular to the dielectric layer.
And a ratio (R1 / R2) of the first average particle size (R1) to the second average particle size (R2) is 2 or more.

Preferably, the first average particle size (R1) is larger than the thickness of the internal electrode layer 3.

[0010] Preferably, the second average particle size (R2) is 2 µm or less.

Preferably, the conductive material particles are made of Ni or a Ni alloy.

Preferably, the dielectric layer is made of BaTiO.
₃ as a main component.

Preferably, the dielectric layer is made of (Ba, C
having a main component containing _{a) (Ti, Zr) O} 3.

In the present invention, the first average particle diameter (R1)
Is defined as follows: That is, the multilayer ceramic electronic component is cut in a cross section perpendicular to the internal electrodes and passing through both external terminal electrodes, and in this cut surface, a straight line substantially parallel to the dielectric layer is drawn in a central portion between the dielectric layers, When the number of conductive material particles intersecting this line is n (n is 10 or more), and the length of the line is L1, L1 / n is the first average particle size (R1). The second average particle diameter (R2) is an average value of the maximum length L2 of each conductive material particle in the thickness direction of the internal electrode layer.

[0015]

The inventors of the present invention have different behaviors when the dielectric layer and the internal electrode layer containing the conductive material particles made of a base metal such as Ni are fired independently and simultaneously. Was confirmed. As a cause, when the dielectric layer and the internal electrode layer are fired simultaneously,
It is presumed that an interaction such as an interface reaction between the dielectric / conductive material particles is involved. Based on such a phenomenon, by controlling the conductive material particles after firing the dielectric layer and the internal electrode layer at the same time to a specific particle size ratio, the interruption of the internal electrode layer is suppressed, thereby obtaining the obtained electrostatic capacity. It has been found that a multilayer ceramic electronic component such as a high-quality capacitor can be obtained, for example, by improving the capacity.

That is, according to the present invention, the obtained electrostatic capacity per unit volume is increased by controlling the conductive material particles to a specific particle size ratio and suppressing interruption of the internal electrode,
Even if the size is reduced, the multilayer ceramic electronic component such as a multilayer ceramic capacitor with high reliability can be realized because it has a large capacity and the smoothness of the interface is improved.

In order to control the conductive material particles contained in the internal electrode layer to a specific particle size ratio, a base metal (for example, N
i) Optimizing various conditions such as the characteristics of powder, the paste composition of the internal electrode layer when it is made into paste, the printing conditions of this paste, the firing conditions, and the composition of the dielectric, and realizing it by carefully controlling these. Can be. Therefore, the method for manufacturing the multilayer ceramic electronic component according to the present invention is not particularly limited, and the state of the conductive material particles after firing may be controlled by optimizing these various conditions.

The multilayer ceramic electronic component is not particularly limited, but may be a multilayer ceramic capacitor, a piezoelectric element,
Examples include chip inductors, chip varistors, chip thermistors, chip resistors, and other surface mount (SMD) chip-type electronic components.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings. FIG. 1 is a schematic sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention, and FIG.
Main part enlarged sectional view of the internal electrode layer shown in FIG.

FIGS. 3A to 3C are photomicrographs showing a cross section and a coated surface of the capacitor sample of Example 1, and FIG.
5A to 5C are micrographs showing a cross section and a coated surface of the capacitor sample of Comparative Example 1, and FIG. 6 is a micrograph of the capacitor sample of Comparative Example 1. 3 is a micrograph of a polished surface of a cross section of FIG.

As shown in FIG. 1, a multilayer ceramic capacitor 1 according to one embodiment of the present invention has a capacitor element body 10 in which dielectric layers 2 and internal electrode layers 3 are alternately stacked.
Having. 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 alternately arranged inside the element body 10. The shape of the capacitor element body 10 is not particularly limited, but is generally a rectangular parallelepiped. The size is not particularly limited, and may be an appropriate size depending on the application.
５5.7 mm) × width (0.3 to 5.0 mm) × thickness (0.3 to 5.0 mm).

The internal electrode layers 3 are laminated so that each end face is alternately exposed on the surfaces of two opposing 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 connected to the exposed end faces of the alternately arranged internal electrode layers 3 to form a capacitor circuit.

Although the composition of the dielectric layer 2 is not particularly limited in the present invention, it is composed of, for example, the following dielectric ceramic composition. The dielectric ceramic composition of the present embodiment preferably has a main component containing, for example, calcium titanate, strontium titanate, and / or barium titanate, and preferably has reduction resistance. The main component, for example a composition formula _{{(Ba (1-x- y} ) Ca x Sr y) O}
Preferably includes a dielectric oxide represented by _{A (Ti (1-z)} Zr z) B O 2. In this case,
A, B, x, y, and z are all in an arbitrary range, for example, 0.9 <A / B <1.05, 0 ≦ x ≦ 1, 0 ≦ y
≦ 1, 0 ≦ z ≦ 1.

The dielectric porcelain composition of the present embodiment contains Sr, Y, Gd, Tb, Dy, V, M
o, Zn, Cd, Ti, Sn, W, Ba, Ca, Mn,
Subcomponents containing at least one selected from oxides of Mg, Cr, Si and P may be contained.

The conditions such as the number of layers and the thickness of the dielectric layer 2 may be appropriately determined according to the purpose and application. For example, the thickness of each dielectric layer 2 is usually 30 μm or less, preferably 10 μm or less, more preferably 5 μm or less, and still more preferably 3 μm or less, and the lower limit is preferably about 0.2 μm. The number of stacked dielectric layers 2 is preferably 50 or more, more preferably 100 or more, and still more preferably 300 or more.

As shown in FIGS. 1 and 2, the internal electrode layer 3 contains conductive material particles 3a. The conductive material particles 3 a are arranged by being arranged one by one in a direction parallel to the dielectric layer 2.

The material of the conductive material particles 3a is not particularly limited in the present invention, but a base metal can be used because the constituent material of the dielectric layer 2 has reduction resistance. Conductive material particles 3
The base metal used as a is not particularly limited,
In the present invention, Ni or a Ni alloy is preferable. When Ni is used as the conductive material particles 3a, a method of firing at a low oxygen partial pressure (reducing atmosphere) is adopted so that the dielectric layer 2 is not reduced. On the other hand, a method of shifting the composition ratio of the dielectric layer 2 from the stoichiometric composition so as not to be reduced may be adopted. As the Ni alloy, Mn, C
at least one element selected from r, Co and Al and N
An alloy with i is preferable, and the Ni content in the alloy is preferably 95% by weight or more. Ni or Ni alloy may contain various trace components such as P, Fe, and Mg in an amount of about 0.1% by weight or less. The thickness d of the internal electrode layer 3 may be appropriately determined according to the application or the like, but is usually 0.5 to 5 μm.
m, preferably about 0.5 to 2.5 μm.

In the present embodiment, the conductive material particles 3a contained in the internal electrode layer 3 have a first average particle size (R1) in a direction parallel to the dielectric layer 2 and a first average particle size (R1) in a direction perpendicular to the dielectric layer 2. 2 average particle size (R2). The first average particle size (R1) is preferably larger than the thickness d of the internal electrode layer 3, and is, for example, 2.5 μm or more, preferably 3 μm or more. Second
The average particle size (R2) is not particularly limited, but is preferably 2 μm or less, more preferably 1.6 μm or less, and the lower limit is about 0.5 μm. If it is thinner than this, the capacity will be significantly reduced due to an increase in breaks.

Further, in the present invention, the ratio (R1 / R2) of the first average particle size (R1) and the second average particle size (R2) described above is used.
Is 2 or more. The larger the ratio (R1 / R2) between the first average particle diameter and the second average particle diameter, the larger the acquired capacitance. However, the ratio of the first average particle size to the second average particle size (R
When (1 / R2) is small, the internal electrode layer 3 tends to be interrupted at the time of firing, and the particles tend to be spheroidized, resulting in a decrease in the obtained capacitance and an increase in short-circuit failure.

The first average particle diameter (R1) is defined as follows. That is, a straight line H substantially parallel to the dielectric layer is provided at a central portion between the dielectric layers 2 on the cut surface shown in FIG.
And the number of conductive material particles 3a intersecting this line is represented by n (n
Is 10 or more), and L1 / n is the first average particle size (R1) when the length of the line is L1. Further, the second average particle diameter (R
2) is an average value of the maximum length L2 of each conductive material particle 3a in the thickness d direction of the internal electrode layer 3. In the present embodiment, the second average particle diameter (R2) is equal to the thickness d of the internal electrode layer 3.

In the present embodiment, it is also preferable that the conductive material particles 3a have a number of steps when observed with a scanning electron microscope (SEM). The effect of the presence of the step is not necessarily clear, but it is considered that this has some effect on the improvement of the acquired capacitance.

Next, a method for manufacturing a multilayer ceramic capacitor according to an embodiment of the present invention will be described. In the present embodiment, the green chip is manufactured by manufacturing a green chip by a normal printing method or a sheet method using a paste, firing the green chip, printing or transferring an external electrode, and firing. Hereinafter, the manufacturing method will be specifically described.

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

According to the composition of the above-mentioned dielectric ceramic composition, the dielectric raw material includes a raw material constituting a main component, a raw material constituting a subcomponent, and a raw material constituting a sintering aid as required. Is used. The raw materials constituting the main component include Ti,
Ba, Sr, Ca, and Zr oxides and / or compounds that become oxides by firing are used. Raw materials constituting the sub-components include Sr, Y, Gd, Tb, Dy, V, M
one or more, preferably three or more, single oxides selected from oxides of o, Zn, Cd, Ti, Ca, Sn, W, Mn, Si and P and / or compounds that become oxides upon firing; A composite oxide is used.

These raw material powders usually have an average particle diameter of 0.005 to 5 μm, preferably about 0.005 to 1 μm. To obtain a dielectric material from such a raw material powder, for example, the following method may be used.

First, the starting materials are blended in a predetermined ratio, and are wet-mixed by, for example, a ball mill or the like. Next, it is dried to obtain a dielectric material of the above formula constituting the main component.

Various additives such as a binder, a plasticizer, a dispersant, and a solvent may be used when preparing the dielectric layer paste. When the paste is fired, the ratio of the dielectric material to the entire paste is about 50 to 80% by weight, the binder is 2 to 5% by weight, the plasticizer is 0.01 to 5% by weight, The dispersant is 0.01 to 5% by weight,
The solvent is about 20 to 50% by weight. Then, the dielectric material and these solvents are mixed to form a paste (slurry).

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

The internal electrode layer paste is made of a conductive material (conductive material particles) made of various conductive metals or alloys, or various oxides, organometallic compounds, resinates, etc. which become the above-mentioned conductive material after firing, and an organic vehicle. And kneaded.

It is preferable to use Ni or a Ni alloy as the conductive material particles used when producing the paste for the internal electrode. The shape of such conductive material particles is not particularly limited, and may be spherical, scaly, or the like, or a mixture thereof. The average particle diameter of the conductive material particles is preferably 0.1 to 2 μm, more preferably 0.2 μm.
What is about 0.8 μm may be used.

The organic vehicle contains a binder and a solvent. As the binder, any known binder such as ethyl cellulose, acrylic resin and butyral resin can be used. Binder content is 1
About 5% by weight. As the solvent, any of known solvents such as terpineol, butyl carbitol, and kerosene can be used. The solvent content is about 20 to 55% by weight based on the entire paste.

The internal electrode layer paste and the dielectric layer paste thus obtained are alternately laminated by a printing method, a transfer method, a green sheet method, or the like. When a 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 separated from the substrate to form a laminate. When the sheet method is used, a green sheet (dielectric layer before sintering) is formed using a dielectric layer paste, and an internal electrode pattern (pre-sintering internal electrode layer) made of the internal electrode layer paste is formed thereon. Print.

A large number of green sheets on which the internal electrode patterns are printed are laminated in the laminating direction to form a laminate, and a plurality of green sheets on which the internal electrode patterns are not printed are also laminated at the upper and lower ends in the laminating direction. .

Next, the laminate thus obtained is
After cutting into a predetermined size of the laminate to form a green chip, binder removal processing and firing are performed. Then, heat treatment is performed to re-oxidize the dielectric layer 2.

The binder removal treatment may be performed under ordinary conditions. When a base metal such as Ni or a Ni alloy is used for the conductive material particles of the internal electrode layer, it is particularly preferable to perform the treatment under the following conditions.

Heating rate: 5 to 300 ° C./hour, especially 10 to 50 ° C./hour, Holding temperature: 200 to 400 ° C., especially 250 to 350 ° C., Holding time: 0.5 to 20 hours, especially 1 to 10 Time and atmosphere: The following conditions are preferable for the humidified mixed gas of N ₂ and H ₂ or the firing conditions in air. Heating rate: 50 to 500 ° C / hour, especially 200 to 300
° C / hour, holding temperature: 1100-1400 ° C, especially 1150-13
50 ° C., holding time: 0.5 to 8 hours, especially 1 to 3 hours, cooling rate: 50 to 500 ° C./hour, especially 200 to 300
° C / hour, atmosphere gas: humidified mixed gas of N ₂ and H ₂ , etc.

[0047] However, the oxygen partial pressure in an air atmosphere at firing ^{is, 10} -2 Pa or less, in particular ^{10 -} 2 ^~10 -8 Pa
It is preferred to carry out at. If it exceeds the range, the internal electrode layer tends to oxidize, and if the oxygen partial pressure is too low, the electrode material of the internal electrode layer causes abnormal sintering,
They tend to break.

In the heat treatment after the firing, the holding temperature or the maximum temperature is preferably set to 1000 ° C. or more.
More preferably, it is preferable to carry out at 1000-1100 ° C. If the holding temperature or the maximum temperature during the heat treatment is less than the above range, the insulation resistance life tends to be short due to insufficient oxidation of the dielectric material, and if the holding temperature or the maximum temperature exceeds the above range, Ni of the internal electrode is oxidized and the capacity is reduced. Not only does it decrease, but it also reacts with the dielectric substrate, which tends to shorten its life. The oxygen partial pressure during the heat treatment is an oxygen partial pressure higher than the reducing atmosphere during the firing, and is preferably 10 ⁻³ Pa to 1 P.
a, more preferably 10 ⁻² Pa to 1 Pa. Below this range, reoxidation of the dielectric layer 2 is difficult, and beyond this range, the internal electrode layer 3 tends to oxidize. The other heat treatment conditions are preferably as follows.

Holding time: 0 to 6 hours, especially 2 to 5 hours, Cooling rate: 50 to 500 ° C./hour, especially 100 to 300
° C / hour, atmosphere gas: humidified N ₂ gas, etc.

In order to humidify the N ₂ gas or the mixed gas, for example, a wetter may be used. In this case, the water temperature is preferably about 0 to 75 ° C. Further, the binder removal treatment, the sintering, and the heat treatment may be performed continuously or independently. When these are continuously performed, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of firing, firing is performed, and then the temperature is lowered to the holding temperature of the heat treatment. It is preferable to perform the heat treatment while changing the atmosphere. In the heat treatment, the temperature may be raised to a holding temperature in an N ₂ gas atmosphere, and then the atmosphere may be changed, or the entire heat treatment may be performed in a humidified N ₂ gas atmosphere.

The sintered body (element body) thus obtained
10) For example, by barrel polishing, sand plasting, etc.
After polishing the end surface, baking the paste for external electrodes
The electrode 4 is formed. The firing conditions for the external electrode paste are as follows:
For example, humidified N₂And H ₂60 in a mixed gas with
It is preferable to set the temperature at 0 to 800 ° C. for about 10 minutes to 1 hour.
Good. Then, if necessary, plating or the like on the external electrode 4
Is performed to form a pad layer. In addition, external electrode
Paste is the same as the internal electrode layer paste described above.
It may be prepared by preparing. Thus, the present invention
Multilayer ceramic capacitors are printed by soldering, etc.
Mounted on a printed circuit board and used in various electronic devices, etc.
You.

In the present embodiment, in order to control the conductive material particles 3a contained in the internal electrode layer 3 to a specific particle size ratio, the characteristics of the base metal (eg, Ni) powder before firing, the internal electrode By optimizing various conditions such as the composition of the layer paste, the printing conditions of this paste, the firing conditions, and the composition of the dielectric, and by carefully controlling these conditions, the multilayer ceramic capacitor 1 having the above-described structure can be realized. In the capacitor 1 thus obtained, the interruption of the internal electrode layer 3 is suppressed, whereby the decrease in the acquired capacitance is improved.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments at all, and can be implemented in various modes without departing from the gist of the present invention. Of course.

For example, in the above-described embodiment, a multilayer ceramic capacitor is exemplified as the multilayer ceramic electronic component according to the present invention. However, the present invention is not limited to this.
Any material may be used as long as it has an element body in which dielectric layers and internal electrode layers are alternately stacked.

[0055]

EXAMPLES The present invention will be described in further detail with reference to examples which embody the embodiments of the present invention. However, the present invention is not limited to only these examples.

[0056]Example 1 Follow the procedure below to connect two multilayer ceramic capacitors.
A pull was made. First, BaTiO₃Part of Ca,
Base material as main component material (base material group) substituted with Zr
Naru: (Ba_0.95, Ca_0.05) (Ti_0.8Z
r_{0.2 )}O₃, Average particle size: 0.7 μm) and sub-components
Y as raw material₂O₃, MnCO₃, SiO₂When
Was used. Then, for 100 mol of the main component material, Y
₂O₃: 0.3 mol, MnCO₃: 0.2 mol,
SiO₂: Weigh 0.16 moles and weigh these
For about 16 hours, and then dry
A dielectric material was obtained. 100 parts by weight of the obtained dielectric material
5.0 parts by weight of an acrylic resin, and benzyl phthalate
2.5 parts by weight of butyl and 6.5 parts by weight of mineral spirit
Parts, 4 parts by weight of acetone and 20.5 parts of trichloroethane.
Parts by weight and 41.5 parts by weight of methylene chloride
To form a paste, thereby obtaining a dielectric layer paste.

100 parts by weight of Ni particles having an average particle diameter of 0.4 μm, 50 parts by weight of an organic vehicle (8 parts by weight of ethyl cellulose dissolved in 92 parts by weight of terpineol),
35 parts by weight of terpineol was kneaded by pot mixing to form a paste, and an internal electrode layer paste was obtained.

A green sheet having a thickness of 5 μm was formed on a PET film by using the dielectric layer paste, and the internal electrode layer paste was printed thereon in a predetermined pattern and dried. The thickness of the internal electrode layer paste after printing and drying was 2 μm. Then, the green sheet is PET
Peeled from the film. A plurality of green sheets on which these internal electrodes were printed were laminated and bonded by pressure to obtain a laminate. Note that the number of stacked dielectric layers 2 was 100.

Next, after cutting the obtained laminate into a predetermined size, binder removal processing, firing and heat treatment were successively performed to obtain two laminated ceramic fired bodies.

The binder removal treatment was performed under the following conditions. Heating rate: 15 ° C / hour, Holding temperature: 280 ° C, Holding time: 8 hours, Atmosphere: In air.

The firing was performed under the following conditions.

Temperature rising rate: 200 ° C./hour, holding temperature: 1245 ° C., holding time: 2 hours, atmosphere: humidified mixed gas of N ₂ and H ₂ , oxygen partial pressure: 10 ⁻⁸ Pa.

The heat treatment was performed under the following conditions.

Holding temperature: 1000 ° C., holding time: 3 hours, cooling rate: 300 ° C./hour, atmosphere: humidified N ₂ gas, oxygen partial pressure: 10 ⁻¹ Pa.

For humidification of each atmosphere gas, a wetter having a water temperature of 0 to 75 ° C. was used.

Next, Cu particles 1 having an average particle size of 0.5 μm
00 parts by weight, 35 parts by weight of an organic vehicle (8 parts by weight of an acrylic resin dissolved in 92 parts by weight of terpineol) and 7 parts by weight of terpineol were kneaded into a paste to obtain a paste for an external electrode.

After polishing the end face of the remaining multilayer ceramic fired body by sandblasting, the external electrode paste was transferred to the end face and fired at 800 ° C. for 10 minutes in a humidified N ₂ + H ₂ atmosphere ( Terminal baking treatment) was performed to form the external electrode 4, and a sample of the multilayer ceramic capacitor 1 shown in FIG. 1 was obtained. The size of the obtained capacitor sample is 3.2 mm × 1.6 mm × 2.
The thickness of the dielectric layer 2 was 3 μm, the thickness of the internal electrode layer 3 was 1.6 μm, and the number of the dielectric layers was 100.

With respect to the obtained sample of the multilayer capacitor, the average particle size of the conductive material particles constituting the internal electrode layer was observed as follows.

The capacitor sample was cut in a section perpendicular to the internal electrodes and passing through both terminal electrodes, and the cut surface was observed with a microscope (SEM). The results are shown in FIGS.
It is shown in (C).

The cut surface was polished and thermally etched, and the polished surface was observed with a microscope (SEM).
The result is shown in FIG. On the polished surface shown in FIG. 4, a straight line H (FIG.
), The number of conductive particles intersecting the line H is n, and the length of the line is L1, where L1 / n is the first average particle diameter (R1) in the direction horizontal to the dielectric layer. did. The thickness of the internal electrode layer was defined as a second average particle size (R2) of the conductive material particles in a direction perpendicular to the dielectric layer.

As a result, the first average particle diameter (R
1) is 5.4 μm, the ratio (R1 / R2) of the first average particle size (R1) to the second average particle size (R2) is 3.4, and the capacitance per unit volume (C) is 12. It was 4 μF. Table 1 shows the results.

The capacitance was measured using a digital LCR meter (4274A manufactured by YHP) at a reference temperature of 25 ° C. and a frequency of 1 kHz and an input signal level (measurement voltage) of 1 Vrms. Was measured.

Referring to FIG. 4, a number of steps were observed in the conductive material particles 3a contained in the internal electrode layer 3.

Comparative Example 1 An internal electrode layer paste was formed in a predetermined pattern on a green sheet formed on a PET film, and the printing conditions were changed so that the thickness of the internal electrode layer paste in the predetermined pattern was 1.5 μm. Except for the above, two samples of the multilayer ceramic capacitor were prepared in the same manner as in Example 1, and the same evaluation was performed.

The obtained multilayer capacitor sample was cut in a cross section perpendicular to the internal electrodes and passing through both terminal electrodes in the same manner as in Example 1, and the cut surface was observed with a microscope (SEM). The results are shown in FIGS. 5 (A) to 5 (C). Also,
The cut surface was polished and thermally etched, and the polished surface was observed with a microscope (SEM). FIG. 6 shows the results.

As a result, the first average particle diameter (R
1) is 2.7 μm, the ratio (R1 / R2) of the first average particle size (R1) to the second average particle size (R2) is 1.5, and the capacitance per unit volume (C) is 11. It was 6 μF. Table 1 shows the results.

Examples 2 to 3 and Comparative Examples 2 to 3 Based on the method of manufacturing the capacitor sample of Example 1, the firing conditions and the particle size of the Ni powder were changed to change the dielectric layer 2 of the conductive material particles. A second average particle size R2 in the vertical direction Y;
A capacitor sample was manufactured so that the ratio (R1 / R2) of the first average particle size to the second average particle size became a value shown in Table 1. The capacitance of the obtained capacitor sample was measured in the same manner as in Example 1. The results are shown in Table 1.

[0078]

[Table 1]

According to Table 1, Examples 1 to 3 and Comparative Examples 1 to 3
As can be seen from the comparison, when the ratio (R1 / R2) of the first average particle size to the second average particle size of the conductive material particles is 2 or more, the obtained capacitance per unit volume is improved. It was confirmed that a multilayer ceramic capacitor having a large capacity and a high reliability can be realized even if it is miniaturized.

[0080]

As described above, according to the present invention, the obtained capacitance per unit volume can be improved, and even if the size is reduced, a large capacity and a highly reliable multilayer ceramic capacitor or the like can be obtained. A ceramic electronic component can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a main part of the internal electrode layer shown in FIG.

FIGS. 3A to 3C are micrographs showing a cross section and a coated surface of the capacitor sample of Example 1. FIG.

FIG. 4 is a micrograph of a cross-section polished surface of the capacitor sample of Example 1.

5 (A) to 5 (C) are photomicrographs showing a cross section and a coated surface of a capacitor sample of Comparative Example 1. FIG.

FIG. 6 is a photomicrograph of a polished cross section of the capacitor sample of Comparative Example 1.

[Description of Signs] 1 ... Multilayer ceramic capacitor 2 ... Dielectric layer 3 ... Internal electrode layer 3a ... Conductive material particles 4 ... External electrode 10 ... Element body

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5E001 AB03 AC09 AD00 AE00 AE02 AE03 5E082 AB03 BC39 EE23 FG01 FG26 PP09

Claims (6)

[Claims] 1. A multilayer ceramic electronic component having a dielectric layer and an internal electrode layer, wherein the internal electrode layer includes conductive material particles arranged in a direction parallel to the dielectric layer. A conductive material particle having a first average particle size (R1) in a direction parallel to the dielectric layer and a second average particle size (R2) in a direction perpendicular to the dielectric layer; Particle size (R1) and the second average particle size (R2)
And the ratio (R1 / R2) is 2 or more. 2. The multilayer ceramic electronic component according to claim 1, wherein the first average particle size (R1) is larger than the thickness of the internal electrode layer 3. 3. The multilayer ceramic electronic component according to claim 1, wherein the second average particle size (R2) is 2 μm or less. 4. The multilayer ceramic electronic component according to claim 1, wherein said conductive material particles are made of Ni or a Ni alloy. 5. The multilayer ceramic electronic component according to claim 1, wherein said dielectric layer has a main component containing BaTiO ₃ . 6. The method according to claim 1, wherein the dielectric layer is (Ba, Ca) (Ti,
The multilayer ceramic electronic component according to claim 1 having a main component containing Zr) O _3.