JP2005294738A - Lamination ceramic electronic component and paste for lamination ceramic electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lamination ceramic electronic component which can reduce a generation of delamination. <P>SOLUTION: A ceramic layer 20 is mainly formed by ceramic dielectric material having a first ceramic particle 31. An auxiliary layer 30 is mainly formed by ceramic dielectric material having a second ceramic particle 32, and a plane in which an inner electrode 12 is formed, furthermore buries a portion in which the inner electrode does not exist. When a mean particle diameter of the first ceramic particle 31 is set to be α (μm), and a weight of a particle which is 1.043×α (μm) or more and 1.122×α (μm) or less in diameter is set to be A, furthermore a weight of a particle which is 0.886×α (μm) or more and 0.965×α (μm) or less in diameter is set to be B, a ratio A/(A+B) satisfies 0.30≤A/(A+B)≤0.65. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a multilayer ceramic electronic component and a paste for multilayer ceramic electronic component.

  Multilayer ceramic electronic components, such as multilayer ceramic capacitors, have a strong market demand for increased capacitance. In order to increase the capacitance, basically, it is necessary to reduce the thickness per ceramic layer to make it multilayer.

Conventionally, in manufacturing a multilayer ceramic electronic component, for example, an internal electrode mainly composed of conductive particles Ni is formed on a dielectric sheet (ceramic green sheet) made of a porcelain composition mainly composed of BaTiO _3. Was formed, laminated, and pressed to form a laminated body.

  In such a method, a step is generated by the thickness of the internal electrode between the portion where the internal electrode is formed and the portion where the internal electrode is not formed, and due to this step, distortion occurs due to shrinkage during firing, The problem that a crack and delamination occur, and the problem that the multilayer ceramic electronic component after firing causes deterioration of electrical characteristics and a decrease in product yield occurred.

  In addition, when the level difference is large, the plane of the fired multilayer ceramic electronic component is deformed into a curved shape, which causes a problem that an adsorption error occurs in the mounter when mounting the board, and a tombstone phenomenon occurs when soldering. These problems become more prominent as the ceramic layer becomes thinner and multilayered. For example, when the number of laminated layers exceeds 100, the problem is so large that it cannot be ignored.

  As means for solving such a problem, for example, in Patent Documents 1 to 6, an auxiliary layer is formed (margin printing) in a portion where the internal electrode is not formed, and a portion where the internal electrode is formed is formed. Disclosed is a multilayer ceramic electronic component that absorbs a level difference between a non-exposed portion.

  Patent Document 7 discloses a multilayer ceramic laminate in which an auxiliary layer can be formed by a printing method and a method for producing the same. In the manufacturing method of Patent Document 7, since the auxiliary layer paste is composed of ceramic particles having a particle size equal to or smaller than the average particle size of the ceramic particles contained in the dielectric layer, the auxiliary is made by the amount of the particles made smaller. The viscosity (viscosity) of the layer paste is increased, and the viscosity required for the printing method can be obtained.

  However, in the manufacturing method of Patent Document 7, since the auxiliary layer paste is configured using ceramic particles having a small particle size, the residual solvent and the binder gas in the laminated body are difficult to completely diffuse and incinerate in the binder removal step. . For this reason, the problem that a crack and delamination generate | occur | produce and the problem of causing the deterioration of an electrical property and the fall of a product yield about the multilayer ceramic electronic component after baking had arisen.

  Further, in the manufacturing method of Patent Document 7, since the auxiliary layer paste is composed of ceramic particles having a particle size equal to or smaller than the average particle size of the ceramic particles contained in the dielectric layer, the dielectric layer is thinned. Accordingly, when the ceramic particles contained in the dielectric layer are reduced, the ceramic particles contained in the auxiliary layer paste are further reduced. For this reason, with the thinning of the dielectric layer, complete divergence and incineration become more difficult, and the above-described problems become more prominent.

Furthermore, when the particle diameter of the ceramic particles contained in the auxiliary layer paste is reduced, the viscosity increases more than necessary, and the printability (printing accuracy) deteriorates.
JP 2001-126951 A JP 2001-358036 A JP 2002-043161 A JP 2002-043164 A JP 2002-043156 A JP 2002-043163 A JP 2002-289456 A

  An object of the present invention is to provide a multilayer ceramic electronic component that can reduce the occurrence of delamination.

  Another object of the present invention is to provide a multilayer ceramic electronic component that can reduce the occurrence of cracks.

  Still another object of the present invention is to provide a monolithic ceramic electronic component having good electrical characteristics.

  Still another object of the present invention is to provide a multilayer ceramic electronic component having a good product yield.

  Still another object of the present invention is to provide a multilayer ceramic electronic component paste suitable for the manufacture of multilayer ceramic electronic components.

  In order to solve the above-described problems, the present invention discloses a multilayer ceramic electronic component and a paste for the multilayer ceramic electronic component.

  The multilayer ceramic electronic component according to the present invention includes a ceramic layer, internal electrodes, and an auxiliary layer. The ceramic layers are a plurality of layers, each of which is mainly composed of a ceramic dielectric material having first ceramic particles. There are a plurality of internal electrodes, each of which is provided in each plane of the ceramic layer and arranged in layers. The auxiliary layer has a ceramic dielectric material having second ceramic particles as a main component, and fills a portion where the internal electrode is not present on the surface on which the internal electrode is formed.

The average particle diameter of the first ceramic particles is α (μm),
Of the second ceramic particles, the weight of particles having a particle size of 1.043 × α (μm) or more and 1.122 × α (μm) or less is A, and the particle size is 0.886 × α ( μm) and 0.965 × α (μm) or less when the weight of the particles is B,
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Meet.

  However, the average particle diameter means an average value of 50 ceramic particle diameters obtained by image analysis of SEM (scanning electron microscope) photographs and approximating the shape of ceramic particles as a sphere.

  In the multilayer ceramic electronic component according to the present invention described above, the ceramic layer has a plurality of layers, each of which is mainly composed of a ceramic dielectric material having first ceramic particles. The ceramic layer is, for example, a dielectric layer when the multilayer ceramic electronic component is a capacitor, and is a magnetic layer when it is an inductor. There are a plurality of internal electrodes, each of which is provided in each plane of the ceramic layer and arranged in layers. One end of the internal electrode is connected to, for example, an extraction electrode formed on the side surface of the multilayer ceramic electronic component, thereby forming a multilayer ceramic capacitor.

  The multilayer ceramic electronic component according to the present invention includes an auxiliary layer. The auxiliary layer has a ceramic dielectric material having second ceramic particles as a main component, and fills a portion where the internal electrode is not formed on the surface on which the internal electrode is formed. For this reason, since the convex step of the internal electrode portion is reduced by the amount of the auxiliary layer, the distortion of the ceramic layer or the internal electrode is reduced, and the occurrence of delamination and cracks is reduced. Preferably, all layers provided with internal electrodes have the above-described configuration.

In the multilayer ceramic electronic component according to the present invention, the auxiliary layer has an average particle diameter of α (μm) of the first ceramic particles, and the particle diameter of the second ceramic particles is 1.043 × α (μm). The weight of particles having a particle size of 1.122 × α (μm) or less is A, and the particle size is 0.886 × α (μm) or more and 0.965 × α (μm) or less. When the weight is B,
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Meet.

  The technical significance of the above conditional expression is as follows.

First, for the ratio A / (A + B) determined by the small particle size and the large particle size,
0.30 ≦ A / (A + B) ≦ 0.65
Appropriate viscosity (viscosity) can be easily realized by satisfying the above. Therefore, the auxiliary layer can be formed by a printing method with a viscosity that optimizes the printing position accuracy (printability) of the auxiliary layer.

  Next, by satisfying the ratio A / (A + B) ≧ 0.30, the second ceramic particles contain only large weight particles A, so that the auxiliary layer is coarser accordingly. (Density is low), and in the binder removal process, the residual solvent in the multilayer ceramic electronic component and the divergence (extraction) and incineration of the binder gas are facilitated. For this reason, in the multilayer ceramic electronic component according to the present invention, generation of delamination, cracks, delamination, and the like is reduced, and a decrease in product yield is avoided.

  In addition, since the multilayer ceramic electronic component according to the present invention facilitates the diffusion and incineration of residual solvent and binder gas, when the multilayer ceramic electronic component is a capacitor, a part of the internal electrode is formed after firing. The high reliability can be maintained by avoiding the problem that the capacitor characteristics are deteriorated due to a short circuit and the breakdown voltage failure caused by the defect of the ceramic layer.

  Further, even when the multilayer ceramic electronic component is thinned and multilayered and the average particle diameter α of the first ceramic particles contained in the ceramic layer is reduced, the second ceramic particles include the first ceramic particles. Since only the weight A includes particles having a particle diameter larger than the average particle diameter α of the particles, the above-described effect is remarkably exhibited.

  When the ratio A / (A + B) is smaller than 0.3, the above-described effects cannot be expected.

  Further, by satisfying the ratio A / (A + B) ≦ 0.65, the second ceramic particles contain only small weight particles B, and the viscosity (viscosity) becomes sufficiently large. Can be formed by a printing method. If the ratio A / (A + B) is greater than 0.65, this advantage cannot be expected.

Preferably, the average particle size α (μm) is
0.2 (μm) ≦ α ≦ 0.8 (μm)
Meet.

The present invention further discloses a paste suitable for manufacturing the above-described multilayer ceramic electronic component. This paste contains ceramic particles. The ceramic particles have a constant α (μm), and the constant α (μm) is
0.2 (μm) ≦ α ≦ 0.8 (μm)
Meet.

Among the ceramic particles, the weight of particles having a particle size of 1.043 × α (μm) or more and 1.122 × α (μm) or less is A, and the particle size is 0.886 × α (μm) or more. And the ratio A / (A + B), where B is the weight of particles that are 0.965 × α (μm) or less,
0.30 ≦ A / (A + B) ≦ 0.65
Meet.

In the production of the multilayer ceramic electronic component, the constant α (μm) defined in the paste corresponds to the average particle diameter α (μm) of the first ceramic particles constituting the dielectric layer. Therefore, according to the paste according to the present invention,
0.2 (μm) ≦ α ≦ 0.8 (μm)
It can be used for manufacturing an auxiliary layer of a multilayer ceramic electronic component that satisfies the above.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

1. 1 is a front sectional view showing one embodiment of a multilayer ceramic electronic component according to the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a partially enlarged view of FIG. The illustrated multilayer ceramic electronic component is, for example, a multilayer ceramic capacitor.

  In FIG. 1, the illustrated multilayer ceramic capacitor includes a capacitor body 4, an internal electrode 12, and terminal electrodes 6 and 8. In FIG. 2, the capacitor body 4 includes a ceramic layer and an auxiliary layer 30. The ceramic layer is, for example, the dielectric layer 20.

  2 and 3, the dielectric layer 20 includes a plurality of layers, each of which is mainly composed of a ceramic dielectric material having first ceramic particles 31. In the illustrated embodiment, the dielectric layer 20 includes, for example, first ceramic particles 31 made of barium titanate, and at least one of rare earth oxide, magnesium oxide, and alkaline earth metal compound as a subcomponent. Including. By including such a subcomponent, a monolithic ceramic capacitor having a flat temperature characteristic can be easily realized.

  The thickness of each dielectric layer 20 is not particularly limited, but is preferably 5 μm or less. More preferably, the thickness of each dielectric layer 20 can be 2 μm or less. The dielectric layer 20 in the illustrated embodiment has, for example, a thickness before firing of 2.4 μm and a thickness after firing of 2 μm.

  As the first ceramic particles 31, it is preferable to use a material that does not grow grains, for example, a B characteristic material (JIS C5101-10). This is because the use of the B characteristic material prevents grain growth during firing and improves capacitor characteristics. Specific examples of the first ceramic particles 31 include dielectric materials such as barium titanate, calcium titanate, and strontium titanate.

  The ceramic particles are not particularly limited in shape, such as spherical or flake shaped, and may be a mixture of these shapes. The particle size is the diameter of the ceramic particles, and the average diameter when the ceramic particles are not spherical. Ceramic particles may be grown by firing and bonded to each other.

The first ceramic particles 31 have an average particle diameter α (μm).
0.01 ≦ α ≦ 1.0
It is preferable to satisfy. More preferably,
0.2 ≦ α ≦ 0.8
Meet. More preferably,
0.2 ≦ α ≦ 0.6
Meet. In the example, the average particle diameter α of the first ceramic particles 31 was set to 0.508 μm.

  There are a plurality of internal electrodes 12, each of which is provided in each plane of the dielectric layer 20, and is arranged in layers via the dielectric layer 20. The material of the internal electrode 12 is not particularly limited, and is composed of, for example, nickel, nickel alloy, silver, palladium, copper, copper alloy, other metal or alloy, or the like. The thickness of the internal electrode 12 is preferably not more than the thickness of the dielectric layer 20. In this embodiment, the internal electrode 12 has a thickness before firing of 1.5 μm.

  The auxiliary layer 30 is manufactured using, for example, a multilayer ceramic electronic component paste according to the present invention described later. The auxiliary layer 30 is mainly composed of a ceramic dielectric material having the second ceramic particles 32, and is a plane on which the internal electrode 12 is formed, and fills a portion where the internal electrode 12 does not exist (margin printing). The thickness of the auxiliary layer 30 is preferably equal to the thickness of the internal electrode 12. In the present embodiment, the auxiliary layer 30 has a thickness before firing of 1.5 μm.

  It is preferable that the auxiliary layer 30 and the dielectric layer 20 as well as the second ceramic particles 32 and the first ceramic particles 31 have the same material composition. This is because when the material composition is the same, the bond between the dielectric layer 20-the auxiliary layer 30-the dielectric layer 20 becomes strong, and problems such as peeling are unlikely to occur.

The second ceramic particles 32 include large particle size ceramic particles 321 and small particle size ceramic particles 322. When the average particle size of the first ceramic particles 31 is α (μm), the particle size D1 (μm) of the large particle size ceramic particles 321 and the particle size D2 (μm) of the small particle size ceramic particles 322 are:
1.043 × α ≦ D1 ≦ 1.122 × α,
0.886 × α ≦ D2 ≦ 0.965 × α.

In the example, since the average particle diameter α of the first ceramic particles 31 is 0.508 μm,
1.043 × α = 0.53,
1.122 × α = 0.57,
0.886 × α = 0.45,
0.965 × α = 0.49
Than,
0.53 (μm) ≦ D1 ≦ 0.57 (μm),
0.45 (μm) ≦ D2 ≦ 0.49 (μm)
It is.

Of the second ceramic particles 32, when the weight of the large particle size ceramic particles 321 is A and the weight of the small particle size ceramic particles 322 is B,
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Meet.

The ratio B / (A + B) is
0.35 ≦ B / (A + B) ≦ 0.70
Meet. For example, when a B-characteristic material is used as the second ceramic particles 32, it can be considered that there is no variation in the particle size of the ceramic particles before and after firing. For this reason, the ratio A / (A + B) can be regarded as constant before and after firing.

  Referring to FIG. 1 again, the terminal electrode 6 is formed on one side of the side surface of the capacitor body 4 and connected to one of the alternately stacked internal electrodes 12. The terminal electrode 8 is formed on the other side of the side surface of the capacitor body 4 and is connected to the other of the alternately laminated internal electrodes 12.

  Although the material of the terminal electrodes 6 and 8 is not specifically limited, For example, copper, a copper alloy, nickel, a nickel alloy, silver, an alloy of silver and palladium, etc. can be used. The thickness of the terminal electrodes 6 and 8 is not particularly limited, but can be, for example, about 10 to 50 μm.

  The shape and size of the multilayer ceramic capacitor can be appropriately determined according to the purpose and application. The multilayer ceramic capacitor has, for example, length (0.6 to 5.6 mm, preferably 0.6 to 3.2 mm) × width (0.3 to 5.0 mm, preferably 0.3 to 1.6 mm) × thickness. (0.1 to 1.9 mm, preferably 0.3 to 1.6 mm).

  The multilayer ceramic electronic component according to the present invention described above includes a ceramic layer 20 and internal electrodes 12. The ceramic layer 20 includes a plurality of layers, each of which is mainly composed of a ceramic dielectric material having the first ceramic particles 31. When the multilayer ceramic electronic component is, for example, a capacitor, the ceramic layer 20 is a dielectric layer. When the multilayer ceramic electronic component is, for example, an inductor, the ceramic layer 20 is a magnetic layer. There are a plurality of internal electrodes 12, each of which is provided in each plane of the ceramic layer 20 and arranged in layers. One end of the internal electrode 12 is connected to, for example, an extraction electrode formed on the side surface of the multilayer ceramic electronic component, and, for example, a multilayer ceramic capacitor is configured.

  The multilayer ceramic electronic component according to the present invention includes an auxiliary layer 30. The auxiliary layer 30 is mainly composed of a ceramic dielectric material having the second ceramic particles 32, and is a plane on which the internal electrode 12 is formed, and fills a portion where the internal electrode 12 does not exist. For this reason, since the convex step due to the internal electrode 12 is reduced by the amount of the auxiliary layer 30, the distortion of the ceramic layer 20 or the internal electrode 12 is reduced, and the occurrence of delamination and cracks is reduced. Preferably, all layers provided with the internal electrode 12 have the above-described configuration.

In the multilayer ceramic electronic component according to the present invention, the average particle diameter of the first ceramic particles 31 is α (μm), and among the second ceramic particles 32, the particle diameter is 1.043 × α (μm) or more, and The weight of particles having a particle size of 1.122 × α (μm) or less is A, and the weight of particles having a particle size of 0.886 × α (μm) or more and 0.965 × α (μm) or less is B When
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Meet.

  Thus, since the ratio A / (A + B) ≧ 0.30 and the second ceramic particles 32 include the particles 321 having a large particle diameter by the weight A, the auxiliary layer 30 is coarser by that amount ( In the binder removal process, residual solvent in the multilayer ceramic electronic component, binder gas divergence (extraction), incineration, and the like are facilitated. For this reason, in the multilayer ceramic electronic component according to the present invention, generation of delamination, cracks, delamination, and the like is reduced, and a decrease in product yield can be avoided.

  In addition, since the multilayer ceramic electronic component according to the present invention facilitates the diffusion and incineration of residual solvent and binder gas, when the multilayer ceramic electronic component is a capacitor, a part of the internal electrode 12 is formed after firing. Therefore, it is possible to avoid the problem that the capacitor characteristics are deteriorated due to short-circuiting and the withstand voltage failure caused by the defect of the ceramic layer 20, and the high reliability can be maintained.

  Furthermore, even when the multilayer ceramic electronic component is thinned and multilayered, and the average particle diameter α of the first ceramic particles 31 included in the ceramic layer 20 is reduced, the second ceramic particles 32 include Since only the weight A includes particles 321 having a larger particle diameter than the average particle diameter α of one ceramic particle 31, the above-described effect is remarkably exhibited.

  Further, the ratio A / (A + B) ≦ 0.65, and the second ceramic particles 32 include only the weight B of the particles 322 having a small particle diameter, and the viscosity (viscosity) becomes sufficiently large. 30 can be formed by a printing method.

Further, since the second ceramic particle 32 includes only the weight A of the large particle size particle 321 in addition to the small particle size particle 322, the small particle size particle 322 and the large particle size particle 321 are used. For a fixed ratio A / (A + B),
0.30 ≦ A / (A + B) ≦ 0.65
By setting as follows, an appropriate viscosity (viscosity) can be easily realized. For this reason, the auxiliary layer 30 can be formed by a printing method with a viscosity that optimizes the printing position accuracy (printability) of the auxiliary layer 30.

  Further, since the auxiliary layer 30 contains only the weight A of ceramic particles 321 having a larger particle diameter than the average particle diameter α of the first ceramic particles 31, the first ceramic particles 31 enter the gaps between the ceramic particles 321. (Anchor effect). For this reason, the dielectric layer 20 and the auxiliary layer 30 are firmly joined, and the occurrence of delamination and cracks is reduced.

  Further, since the auxiliary layer 30 includes not only the large particle size ceramic particles 321 but also the small particle size ceramic particles 322, the density of the second ceramic particles 32 is increased. For this reason, shrinkage | contraction and deformation | transformation at the time of baking are suppressed and generation | occurrence | production of a crack reduces.

  Table 1 shows that the multilayer ceramic capacitors according to Examples 1 to 5 and the multilayer ceramic capacitors according to Comparative Examples 1 to 7 were prepared for each Example and Comparative Example in units of 10,000, resulting in delamination, crack failure, It is the result of examining the occurrence rate of voltage failure (short failure). FIG. 4 is a diagram showing the incidence of delamination, crack failure, and withstand voltage failure shown in Table 1, and FIG. 5 is a partially enlarged view of FIG.

  Examples 1 to 5 are multilayer ceramic capacitors according to the present invention. Example 1 regarding the ratio P1 = A / (A + B) (expressed in wt%) of the large particle size ceramic particles 321 and the ratio P2 = B / (A + B) (expressed in wt%) of the small particle size ceramic particles 322 Then, P1 = 30, P2 = 70, Example 2 is P1 = 35, P2 = 65, Example 3 is P1 = 40, P2 = 60, Example 4 is P1 = 50, P2 = 50, Example In Example 5, P1 = 65 and P2 = 35.

  The multilayer ceramic capacitors according to Examples 1 to 5 were produced as follows.

  First, a dielectric slurry for green sheets is prepared. The dielectric slurry is composed of 100 parts by weight of a dielectric ceramic material powder mainly composed of a ceramic dielectric material having the first ceramic particles 31, 4.5 parts by weight of ethyl cellulose resin, 90 parts by weight of terpineol, benzylbutyl phthalate ( BBP): 6.3 parts by weight. The average particle diameter α of the first ceramic particles 31 was α = 0.508 μm.

  Using the above slurry for green sheets, a dielectric slurry film was formed on a carrier sheet by a nozzle method to obtain a dielectric green sheet (dielectric layer 20) having a thickness of 2.4 μm after drying. On this dielectric green sheet, the internal electrode 12 was screen-printed using a conductor paste. The thickness of the internal electrode 12 after drying was 1.5 μm.

  Next, the auxiliary layer 30 was screen-printed using the paste according to the present invention in order to fill the electrode level difference caused by the internal electrode 12. The auxiliary layer 30 has the same components as the dielectric layer 20, and the ratios P1 and P2 (wt%) are the values shown in Table 1. The thickness of the auxiliary layer 30 after drying was the same as that of the internal electrode 12.

  Next, the dielectric green sheets provided with the internal electrodes 12 and the auxiliary layers 30 were stacked while being aligned so that the internal electrodes 12 were alternately formed to obtain a 300-layer laminate. The upper and lower sides of the laminate were sandwiched between outer dielectric sheets having a thickness of 100 μm, pressed and cut to form ceramic green laminate chips. The laminate chips were subjected to binder removal processing and fired to obtain capacitor substrates. The thickness of the dielectric layer 20 after firing was 2 μm.

  The binder removal, firing and annealing conditions were, for example, binder removal at 280 ° C. for 12 hours and firing in a reducing atmosphere at 1300 ° C. for 2 hours. The annealing process was performed at about 1000 ° C. for 2 hours.

Finally, terminal electrodes 6 and 8 were provided on both end faces of the capacitor substrate, and the multilayer ceramic capacitors according to Examples 1 to 5 were completed. The terminal electrode was formed by, for example, using copper as a main component, baking at 800 ° C. for 30 minutes in N ₂ + H ₂ , and then plating.

  The multilayer ceramic capacitors according to Comparative Examples 1 to 7 are multilayer ceramic capacitors to be compared with the multilayer ceramic capacitors according to Examples 1 to 5. Comparative Example 1 is a multilayer ceramic capacitor that does not have an auxiliary layer. In Comparative Examples 2 to 7, the ratios P1 and P2 (wt%) are different from those of the multilayer ceramic capacitor according to this example. Comparative Example 2 is P1 = 0, P2 = 100, Comparative Example 3 is P1 = 20, P2 = 80, Comparative Example 4 is P1 = 70, P2 = 30, Comparative Example 5 is P1 = 80, P2 = 20, P1 = 90 and P2 = 10 in Comparative Example 6, and P1 = 100 and P2 = 0 in Comparative Example 7.

  Regarding delamination, 50 samples were randomly selected from the 10,000 samples, and cross-sectional observation was performed with a microscope to determine the number of samples in which delamination occurred.

  As for crack defects, 1000 samples were selected at random from 10,000 samples, and an appearance inspection was performed to determine the number of samples in which crack defects occurred.

  With respect to the withstand voltage failure, a withstand voltage failure test was performed on 10,000 pieces, and the number of defective samples was obtained. The test of withstand voltage failure was performed under the condition of DC75V, and the product with 0.5% or more was judged as defective.

表１を参照すると、比較例１は、クラックは発生していないが、デラミネーション発生率が１４％と高く、耐電圧不良の発生率が０．８％と高い。比較例２〜７は、デラミネーション発生率が４％〜１２％と高く、クラックの発生率が０．５％〜１．０％と高く、耐電圧不良の発生率が１．３％〜２．６％と高い。

Referring to Table 1, Comparative Example 1 has no crack, but has a high delamination occurrence rate of 14% and a high withstand voltage failure rate of 0.8%. In Comparative Examples 2 to 7, the delamination occurrence rate is as high as 4% to 12%, the crack occurrence rate is as high as 0.5% to 1.0%, and the withstand voltage failure occurrence rate is 1.3% to 2%. High as 6%.

  On the other hand, in Example 1, the delamination occurrence rate is as low as 0.0% to 2.0%, the crack occurrence rate is as low as 0.0% to 0.4%, and the withstand voltage failure occurrence rate is low. Is as low as 0.0% to 0.2%, and good characteristics are obtained. In particular, Example 3 has an occurrence rate of delamination, cracks, and withstand voltage failure of 0.0%, and extremely good characteristics are obtained.

  Further, referring to FIG. 4, the occurrence rate of delamination, crack failure, and withstand voltage failure between the ratio P1 = 20 (wt%) in Comparative Example 3 and the ratio P1 = 30 (wt%) in Example 1. Shows unusual characteristics.

  Further, an unusual characteristic appears in the occurrence rate of withstand voltage failure between the ratio P1 = 65 (wt%) in Example 5 and the ratio P1 = 70 (wt%) in Comparative Example 4, resulting in delamination and crack failure. A significant difference appears in the incidence of.

  Furthermore, referring to FIG. 5, the delamination occurrence rate is very good between the ratio P1 = 35 (wt%) in Example 2 and the ratio P1 = 50 (wt%) in Example 4. As for the occurrence rate of crack failure, extremely good characteristics were obtained at the ratio P1 = 40 (wt%) of Example 3, and the occurrence rate of defective withstand voltage was the ratio P1 = 35 (Example 1). wt%) and the ratio P1 = 40 (wt%) in Example 3 are very good.

  In addition, in the case of other particle sizes selected in the range of 0.2 (μm) ≦ α ≦ 0.8 (μm), the same results as those shown in Table 1 were obtained.

2. About the manufacturing method of a multilayer ceramic capacitor, and the paste for multilayer ceramic electronic components Next, one Example of the manufacturing method of the multilayer ceramic capacitor shown in FIGS. 1-3 is described with reference to FIGS. .

  First, in order to manufacture a ceramic green sheet, a dielectric slurry (a slurry for a green sheet) is prepared. This dielectric slurry will later become the dielectric layer 20.

  The dielectric slurry is composed of an organic solvent-based paste obtained by kneading a dielectric ceramic material (including the first ceramic particles 31) and an organic vehicle. The dielectric ceramic material is not particularly limited. In addition to barium titanate, lead-containing perovskite, alumina, etc., a composition containing various inorganic additives for function development as a temperature compensation material or a high dielectric constant material. The system can be appropriately selected and used. These raw materials are appropriately selected from various compounds to be complex oxides and oxides, such as carbonates, nitrates, hydroxides, organometallic compounds, and the like, and can be used in a mixture. In order to form an extremely thin green sheet, it is desirable to use powder (particles) finer than the thickness of the green sheet.

Specifically, the average particle diameter α (μm) of the first ceramic particles 31 is
0.01 (μm) ≦ α ≦ 1.0 (μm)
It is preferable to satisfy. More preferably,
0.2 (μm) ≦ α ≦ 0.8 (μm)
Meet. More preferably,
0.2 (μm) ≦ α ≦ 0.6 (μm)
Meet. By setting such an average particle diameter, even if the thickness of the dielectric layer 20 is reduced to, for example, 2 μm or less, it is possible to reduce delamination defects and crack defects.

  An organic vehicle is obtained by dissolving an organic binder component in an organic solvent. The organic binder component means a polymer resin as a binder resin, or a polymer resin and a plasticizer. The organic solvent used for the organic vehicle is not particularly limited, and organic solvents such as terpineol, butyl carbitol, acetone, toluene and the like are used.

  The polymer resin used in the organic vehicle is not particularly limited, and is a cellulose resin including various cellulose derivatives such as cellulose ester and cellulose ether, an acetal resin, a butyral resin, acrylic acid, and an acrylic resin obtained by polymerizing the derivative. Methacrylic acid, methacrylic acid and its derivatives, ethylene, or various copolymers of propylene and vinyl acetate, acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, glycidyl acid, glycidyl ester, etc. Examples thereof include olefin-based resins, urethane resins, and epoxy resins, and one or more of them can be selected as appropriate.

  The plasticizer is not particularly limited, but phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, and benzyl butyl phthalate, as well as aliphatic dibasic acid esters and phosphate esters are used. Is done.

  In general, the organic binder component (polymer resin + plasticizer) in the dielectric slurry is desirably 3 to 16% by weight based on the dielectric ceramic material powder, and the amount of plasticizer added is based on the polymer resin. 100% by weight or less is desirable.

  When the organic binder component is 3% by weight or less, the effect of binding the ceramic material powder is small, the ceramic material tends to fall off from the green sheet, and the strength of the sheet tends to deteriorate. Further, when the organic binder component exceeds 16% by weight, the amount of the organic component relative to the dielectric ceramic material powder is relatively increased, so that the time required for the binder removal becomes longer, and the dielectric ceramic material powder in the green sheet. Therefore, the volume shrinkage in the binder removal process increases, which tends to lead to problems such as a decrease in final chip size accuracy, deformation of the electrode layer, and an increase in cracks.

  On the other hand, when the amount of the plasticizer exceeds 100% by weight, the strength of the dielectric green sheet decreases, and defects in the sheet tend to increase due to difficulty in peeling from the support film.

  The dielectric slurry may contain additives selected from various dispersants, antistatic agents, dielectrics, glass frit, insulators, and the like as necessary. However, the total content of these is preferably 10% by weight or less.

  Specifically, the slurry for green sheets was produced as follows, for example.

First, BaTiO ₃ powder (first ceramic particles) having an average particle diameter of 0.508 μm obtained by a hydrothermal method was used as a starting material. For this BaTiO ₃ powder 100 _{mol%, (Ba 0.6 Ca 0.4)} SiO 3: 3 mol%, Y ₂ O _{3: 2} mol%, MgCO _3: 2 mol% (MgO terms), MnCO _3: 0. 4 mol% (MnO conversion) and V ₂ O _5: so that 0.1 mol%, 16 h wet mixed by a ball mill, then a dielectric ceramic material powder is dried in a spray dryer.

  100 parts by weight of the above dielectric ceramic material powder, 6 parts by weight of polyvinyl butyral resin (PVB), 3 parts by weight of dioctyl phthalate (DOP) as a plasticizer, 60 parts by weight of methyl ethyl ketone, 40 parts by weight of ethanol, toluene 20 parts by weight was wet-mixed with a ball mill containing zirconia media having a diameter of 1 mm for 20 hours to obtain a dielectric slurry (green sheet slurry). The ratio of the organic binder component in the dielectric slurry was 9% by weight with respect to the dielectric ceramic material powder.

  Next, as shown in FIG. 6, using the doctor blade 90 etc., the said dielectric slurry is apply | coated on the carrier sheet 19 as a support sheet, the green sheet 51 is formed, and it is made to dry. As the carrier sheet 19, for example, a PET film or the like is used, and a film coated with silicon or the like is preferable in order to improve peelability. Although the thickness of these carrier sheets 19 is not specifically limited, Preferably, it is 5-100 micrometers. The drying temperature of the green sheet 51 is preferably 50 to 100 ° C., and the drying time is preferably 1 to 5 minutes. The thickness of the green sheet 51 after drying is preferably 3.0 μm or less, more preferably 1.2 μm or more and 2.5 μm or less.

  Next, as shown in FIG. 7, the internal electrode 12 having a predetermined pattern is formed on the surface of the green sheet 51 by a printing method, a transfer method, or the like, and dried. Examples of the printing method include a screen printing method and a gravure printing method.

  The electrode paste used for printing the internal electrode 12 is, for example, a conductive material made of various conductive metals or alloys, or various oxides, organometallic compounds, or resinates that become the conductive material described above after firing, and an organic vehicle. Can be prepared by kneading.

  As a conductive material used when manufacturing the electrode paste, Ni, Ni alloy, or a mixture thereof is used. There are no particular restrictions on the shape of such a conductive material, such as a spherical shape or a flake shape, or a mixture of these shapes may be used. The average particle diameter of the conductor material may be, for example, about 0.1 to 2 μm, preferably about 0.2 to 1 μm. The organic vehicle for the electrode paste is the same as the organic vehicle for the green sheet slurry. In order to improve adhesion, the electrode paste preferably contains a plasticizer.

  Specifically, the internal electrode paste (transferred electrode layer paste) was produced, for example, as follows.

  To 100 parts by mass of Ni particles having an average particle diameter of 0.4 μm, 100 parts by mass of an organic vehicle (5 parts by mass of ethyl cellulose resin dissolved in 95 parts by mass of terpineol) was added and kneaded by three rolls. An internal electrode paste was obtained.

  Next, a paste for multilayer ceramic electronic component (printing paste for absorbing an electrode step) according to the present invention is prepared. FIG. 8 is a diagram schematically showing the composition of the multilayer ceramic electronic component paste according to the present invention. The illustrated multilayer ceramic electronic component paste is an organic solvent-based paste containing ceramic particles 32 and another paste composition 11 such as an organic vehicle and a common material.

  The organic vehicle includes an organic binder component (polymer resin + plasticizer), a solvent, and various additives, like the paste used to form the dielectric layer 20. As these polymer resin, plasticizer, solvent and various additives, for example, the same paste as that used for forming the dielectric layer 20 can be used.

  The material of the ceramic particles 32 is not particularly limited. For example, it is made of a dielectric material such as calcium titanate, strontium titanate and / or barium titanate. In the embodiment, the ceramic particles 32 are made of, for example, barium titanate.

The ceramic particles 32 include large particle size ceramic particles 321 and small particle size ceramic particles 322. The constant is α (μm),
0.2 (μm) ≦ α ≦ 0.8 (μm)
, The particle size D1 (μm) of the large particle size ceramic particles 321 and the particle size D2 (μm) of the small particle size ceramic particles 322 are:
1.043 × α ≦ D1 ≦ 1.122 × α,
0.886 × α ≦ D2 ≦ 0.965 × α.

The constant α (μm) is
α ≦ 0.6
It is further more preferable to satisfy | fill.

The constant α (μm) corresponds to the average particle diameter α (μm) of the first ceramic particles 31. In this embodiment, α = 0.508 μm,
0.53 (μm) ≦ D1 ≦ 0.57 (μm),
0.45 (μm) ≦ D2 ≦ 0.49 (μm)
It becomes.

Among the ceramic particles 32, when the weight of the large particle size ceramic particles 321 is A and the weight of the small particle size ceramic particles 322 is B,
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Meet.

  The paste was produced as follows, for example.

First, the ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Ceramic particles 32 satisfying the above conditions are prepared. The ceramic particles 32 were selectively sorted with a sieve or the like. Except for mixing them at each ratio, with respect to 100 parts by weight of the dielectric ceramic material powder used in the above-mentioned slurry for green sheets, 4.5 parts by weight of ethyl cellulose resin as a polymer resin and 6.3 parts by weight of pendyl butyl phthalate (BBP) and 90 parts by weight of terpineol as a solvent were added and wet-mixed for 15 hours in a mixer mill containing zirconia media having a diameter of 1 mm to obtain a paste.

  The ratio of the organic bonding component (polymer resin + plasticizer) in the paste is, for example, 10.8 wt% with respect to the dielectric ceramic material powder, and the organic bonding component ratio in the above-mentioned slurry for green sheets is 9 wt%. The composition is 1.8% by weight more than%. The amount of plasticizer in the paste is 140% by weight with respect to the polymer resin.

  Next, as shown in FIGS. 9 and 10, the inner electrode 12 and the inner electrode 12 are substantially formed by, for example, a printing method or a transfer method so as to fill a gap in a portion where the inner electrode 12 does not exist on the surface of the green sheet 51. The auxiliary layer 30 is applied to the same thickness and dried. Examples of the printing method include a screen printing method and a gravure printing method.

  Next, as shown in FIG. 11, the green sheet 51 on which the internal electrode 12 and the auxiliary layer 30 are formed is cut into a predetermined size, and the cut green sheets 51 are stacked to form a stacked body. Exterior sheets 52 are provided on the upper and lower surfaces of the laminate.

  Since the auxiliary layer 30 includes the large-diameter ceramic particles 321 only by the weight A, the auxiliary layer becomes coarse (low density) correspondingly, and in the stacking process of the green sheet 51, the dielectric layer 20-auxiliary layer. The deviation between 30 can be reduced. For this reason, the positional deviation of the internal electrode patterns between the respective layers is reduced, and the manufacturing yield is improved.

As shown in FIG. 12, the laminate is cut at a predetermined position. Thereafter, the laminate is subjected to binder removal processing and firing processing. The binder removal treatment may be performed under normal conditions, but when a base metal such as Ni or Ni alloy is used for the conductor material of the internal electrode 12, it is particularly preferable to perform under the following conditions.
Temperature increase rate: 5 to 300 ° C./hour, particularly 10 to 50 ° C./hour,
Holding temperature: 200-400 ° C, especially 250-350 ° C,
Retention time: 0.5 to 20 hours, especially 1 to 10 hours,
Atmosphere: A mixed gas of humidified N ₂ and H ₂ .

Moreover, the following conditions are preferable for baking conditions.
Temperature increase rate: 50 to 500 ° C./hour, particularly 200 to 300 ° C./hour,
Holding temperature: 1100-1300 ° C., in particular 1150-1250 ° C.
Retention time: 0.5-8 hours, especially 1-3 hours,
Cooling rate: 50-500 ° C / hour, especially 200-300 ° C / hour,
Atmospheric gas: A mixed gas of humidified N ₂ and H ₂ or the like.

The oxygen partial pressure in the air atmosphere at the time of firing is preferably 10 ⁻² Pa or less, particularly preferably in the range of 10 ⁻² to 10 ⁻⁸ Pa. If the above range is exceeded, the internal electrode 12 tends to oxidize, and if the oxygen partial pressure is too low, the electrode material of the internal electrode 12 tends to abnormally sinter and tend to break.

  The heat treatment after firing is performed by setting the holding temperature or the maximum temperature to a temperature of preferably 1000 ° C. or higher, more preferably 1000 to 1100 ° C. If the holding temperature or maximum temperature during the heat treatment is less than the above range, the dielectric material is not sufficiently oxidized, so that the insulation resistance life tends to be shortened. Not only decreases, but also reacts with the dielectric substrate, and the lifetime tends to be shortened.

The oxygen partial pressure during the heat treatment is higher than that in the reducing atmosphere during firing, and is preferably in the range of 10 ⁻³ Pa to 1 Pa, more preferably 10 ⁻² Pa to 1 Pa. If it is less than the above range, reoxidation of the dielectric layer 202 is difficult, and if it exceeds the above range, the internal electrode 12 tends to be oxidized.

Other heat treatment conditions are preferably the following conditions.
Retention time: 0-6 hours, especially 2-5 hours,
Cooling rate: 50 to 500 ° C./hour, in particular 100 to 300 ° C./hour,
Atmospheric gas: humidified N ₂ gas or the like.

Note that to wet the N ₂ gas or mixed gas etc. may be used, for example a wetter etc.. In this case, the water temperature is preferably about 0 to 75 ° C. Further, the binder removal treatment / firing and heat treatment may be performed continuously or independently. When performing these continuously, after removing the binder, the atmosphere is changed without cooling, and then the temperature is raised to the holding temperature at the time of baking to perform baking, and then cooled to reach the heat treatment holding temperature. Sometimes it is preferable to perform heat treatment by changing the atmosphere.

On the other hand, when performing these independently, at the time of firing, after raising the temperature under N ₂ gas atmosphere with N ₂ gas or wet to the holding temperature of the binder removal processing, further continuing the heating to change the atmosphere Preferably, after cooling to the holding temperature at the time of heat treatment, it is preferable to change to the N ₂ gas or humidified N ₂ gas atmosphere again and continue cooling. In the heat treatment, the temperature may be changed to a holding temperature in an N ₂ gas atmosphere and then the atmosphere may be changed, or the entire heat treatment process may be a humidified N ₂ gas atmosphere.

  The laminated body (sintered body) thus obtained is subjected to end face polishing by, for example, barrel polishing, sand blasting, etc., and terminal electrode paste is baked to form terminal electrodes 6 and 8.

The firing conditions for the terminal 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 pad layer is formed on the terminal electrodes 6 and 8 by plating or the like. In addition, what is necessary is just to prepare the paste for terminal electrodes like the above-mentioned electrode paste.

  Although the contents of the present invention have been specifically described with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

1 is a front sectional view showing an embodiment of a multilayer ceramic electronic component according to the present invention. It is the elements on larger scale of FIG. FIG. 3 is a partially enlarged view of FIG. 2. It is a figure which shows the incidence rate of the delamination shown in Table 1, a crack defect, and a withstand voltage defect. It is the elements on larger scale of FIG. It is process drawing explaining one Example of the manufacturing method of a multilayer ceramic electronic component. It is another process drawing explaining one Example of the manufacturing method of a multilayer ceramic electronic component. It is a figure which shows typically the composition of the paste for multilayer ceramic electronic components which concerns on this invention. It is another process drawing explaining one Example of the manufacturing method of a multilayer ceramic electronic component. It is another process drawing explaining one Example of the manufacturing method of a multilayer ceramic electronic component. It is another process drawing explaining one Example of the manufacturing method of a multilayer ceramic electronic component. It is another process drawing explaining one Example of the manufacturing method of a multilayer ceramic electronic component.

Explanation of symbols

20 Dielectric layer 31 First ceramic particle 30 Auxiliary layer 32 Second ceramic particle 321 Large particle size ceramic particle 322 Small particle size ceramic particle 12 Internal electrode

Claims (5)

A multilayer ceramic electronic component including a ceramic layer, an internal electrode, and an auxiliary layer,
The ceramic layers are a plurality of layers, each of which is mainly composed of a ceramic dielectric material having first ceramic particles,
The internal electrodes are plural, each provided in a plane of the ceramic layer, and arranged in layers,
The auxiliary layer is mainly composed of a ceramic dielectric material having second ceramic particles, and fills a portion where the internal electrode does not exist on the surface on which the internal electrode is formed,
The average particle diameter of the first ceramic particles is α (μm),
Of the second ceramic particles, the weight of particles having a particle size of 1.043 × α (μm) or more and 1.122 × α (μm) or less is A, and the particle size is 0.886 × α. When the weight of the particles that are not less than (μm) and not more than 0.965 × α (μm) is B,
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
Meet multilayer ceramic electronic components. The multilayer ceramic electronic component according to claim 1,
The average particle diameter α (μm) of the first ceramic particles is
0.2 ≦ α ≦ 0.8
Meet multilayer ceramic electronic components. A multilayer ceramic electronic component according to claim 2,
The average particle diameter α (μm) of the first ceramic particles is
α ≦ 0.6
Meet multilayer ceramic electronic components. A multilayer ceramic electronic component paste containing ceramic particles,
When the constant is α (μm), the constant α (μm) is
0.2 ≦ α ≦ 0.8
The filling,
Among the ceramic particles, the weight of particles having a particle size of 1.043 × α (μm) or more and 1.122 × α (μm) or less is A, and the particle size is 0.886 × α (μm). When the weight of the particles that are 0.965 × α (μm) or less is B,
The ratio A / (A + B) is
0.30 ≦ A / (A + B) ≦ 0.65
A paste for multilayer ceramic electronic components that meets the requirements. The multilayer ceramic electronic component paste according to claim 4,
The constant α (μm) is
α ≦ 0.6
A paste for multilayer ceramic electronic components that meets the requirements.

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