JP3042463B2 - Manufacturing method of ceramic electronic components - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a ceramic electronic component such as a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art FIG. 2 is a partially cutaway perspective view of a general multilayer ceramic capacitor, in which 10 is a ceramic dielectric layer, 3 is an internal electrode, 11 is an external electrode, and 3 is an internal electrode.
Are connected to the external electrodes 11 respectively.

Hereinafter, a method for manufacturing a conventional multilayer ceramic capacitor will be described. First, a dielectric material such as barium titanate, a binder component such as polyvinyl butyral, a plasticizer component such as benzyl butyl phthalate, and a solvent component are mixed and slurried, and then PET or the like is formed using a doctor blade method. Is formed on the base film of (1). Next, a plurality of metal pastes to be the internal electrodes 3 are formed on the ceramic sheet. Next, after laminating the ceramic sheets on which the internal electrodes 3 are formed on a rigid support via an adhesive layer, the ceramic sheets are pressed together by a hydrostatic pressure press to obtain a laminate block. Next, this laminate block is cut into a laminate having a predetermined chip shape, and after firing, external electrodes 11 are provided on both end surfaces to obtain a multilayer ceramic capacitor.

[0004]

However, according to the above method, when the adhesive force of the adhesive layer is strong, there is a problem that the laminated body is difficult to separate from the support after cutting.

Accordingly, an object of the present invention is to provide a method of manufacturing a ceramic electronic component which can be easily separated into individual laminates after pressure bonding.

[0006]

In order to achieve this object, a method for manufacturing a ceramic electronic component according to the present invention comprises a polyethylene and a ceramic raw material and a porosity of 3%.
A first step of arranging at least one sheet of at least one first ceramic sheet on a support; and a second step of forming a conductive layer of a desired shape on the upper surface of the first ceramic sheet. A second step of laminating a plurality of ceramic sheets to form a laminate block, and then press-bonding the laminate block, cutting it into a laminate of a desired shape, and above the softening point of the polyethylene, the melting point of the polyethylene A method for producing a ceramic electronic component, comprising: a third step of separating the individual laminates after maintaining the temperature at a temperature of less than or less, and a fourth step of subsequently firing the laminates.

According to this method, in the third step,
The sudden shrinkage of the first ceramic sheet containing polyethylene allows easy separation into individual laminates.

[0008]

DETAILED DESCRIPTION OF THE INVENTION According to the first aspect of the present invention, at least one first ceramic sheet containing polyethylene and a ceramic raw material and having a porosity of 30% or more is disposed on a support. A first step, and then a second step of forming a laminate block by laminating a plurality of second ceramic sheets having a conductor layer of a desired shape formed on the upper surface of the first ceramic sheet. And a third step of cutting the laminate into blocks having a desired shape after the laminate block is press-bonded, separating the laminate into individual laminates after maintaining at a temperature equal to or higher than the softening point of the polyethylene and lower than the melting point of the polyethylene. And a fourth step of baking the laminate thereafter. In the third step, the laminate can be easily separated into individual laminates.

According to a second aspect of the present invention, there is provided the method of manufacturing a ceramic electronic component according to the first aspect, wherein a ceramic sheet containing an organic component which is hardly reactive with polyethylene is used as the second ceramic sheet. This makes it easier to separate the individual laminates in the process.

According to a third aspect of the present invention, there is provided the method for producing a ceramic electronic component according to the second aspect, wherein polyvinyl butyral is used as the organic component which is less likely to react with polyethylene. It is easy to separate into a laminate.

According to a fourth aspect of the present invention, there is provided the method for manufacturing a ceramic electronic component according to any one of the first to third aspects, wherein the thickness of the first ceramic sheet is at least 40 μm. A ceramic electronic component free from structural defects such as cracks can be obtained by absorbing the steps between the portion of the block where the conductive layer is formed and the portion where the conductive layer is not formed.

According to a fifth aspect of the present invention, there is provided the method for manufacturing a ceramic electronic component according to any one of the first to fourth aspects, wherein the temperature in the third step is 60 to 140 ° C. By rapidly shrinking the first ceramic sheet containing, it is possible to separate easily into individual laminates.

An embodiment of the present invention will be described below by taking a multilayer ceramic capacitor as an example.

(Embodiment 1) FIG. 1 is a cross-sectional view for explaining one manufacturing process of the multilayer ceramic capacitor according to the present embodiment.

1 is a first ceramic sheet, 2 is a second ceramic sheet, 3 is an internal electrode, 4 is an internal electrode forming portion, 5 is an internal electrode non-forming portion, and 6 is a first ceramic sheet 1 and a second ceramic sheet. The interface 7 with the ceramic sheet 2 is a support.

First, a first ceramic sheet 1 having a porosity of 70% and a thickness of about 80 μm is prepared using polyethylene having a weight average molecular weight of 400,000 and a dielectric powder mainly containing barium titanate. . Next, the first ceramic sheet 1 is disposed on a rigid support 7 made of a stainless steel plate having a thickness of 1.0 mm or an alumina plate having a thickness of 3.0 mm. Next, a dielectric powder containing barium titanate as a main component, a binder component composed of polyvinyl butyral resin, a plasticizer component composed of benzyl butyl phthalate, and a solvent component composed of isopropanol were mixed and slurried. In FIG. 2, a second dielectric dielectric layer 10 is formed.
Is manufactured. The thickness of the second ceramic sheet 2 is about 15 μm. Further, on this upper surface, a plurality of internal electrodes 3 mainly composed of nickel are formed in a desired shape. The thickness of the internal electrode 3 is 2.5 μm. Next, after forming a laminate block in which 150 pieces of the second ceramic sheet 2 on which the internal electrodes 3 are formed are sequentially laminated so that the internal electrodes 3 face each other with the second ceramic sheet 2 interposed therebetween, the laminate block is formed. Into a bag made of a flexible material or the like together with the support 7, vacuum-packaged, 85 ° C., 200 kg / c.
After isostatic pressing at m ² , the second ceramic sheets 2 are bonded together. Heating to 85 ° C. is a temperature at which the polyvinyl butyral resin softens, and adhesion between the second ceramic sheets 2 occurs. Further, the first ceramic sheet 1 has a higher porosity and elasticity as compared with the second ceramic sheet 2 made of a conventional polyvinyl butyral resin and ceramic powder, so that the first ceramic sheet 1 looks like a cushion during hydrostatic pressing. , The first ceramic sheet 1 immediately below the internal electrode forming portion 4
Indicates a high compression ratio, and the first ceramic sheet 1 immediately below the internal electrode non-formed portion 5 has a low compression ratio, so that not only the internal electrode formed portion 4 but also the internal electrode non-formed portion 5 A sufficient pressure can be applied, and the adhesion of the internal electrode forming portion 4 becomes strong, so that the occurrence of cracks can be suppressed. Furthermore, the interface 6 between the first ceramic sheet 1 and the second ceramic sheet 2 does not substantially have a strong bond, but is physically due to unevenness of the surfaces of the first and second ceramic sheets 1 and 2. Relatively weak adhesion. Thereafter, the laminate block is cut into a chip-shaped laminate having a length of 3.2 mm and a width of 1.6 mm by a push-cut method, and then left in the air at 110 ° C. for about 15 minutes.
At this time, the first ceramic sheet 1 containing polyethylene starts to shrink sharply, whereas the second ceramic sheet 2 containing polyvinyl butyral resin does not shrink, so that it is easily separated into individual laminates. The separated layered product is de-built at 300 ° C. in the air, and fired in an oxygen concentration atmosphere equal to or lower than the equilibrium oxygen partial pressure of nickel to obtain a sintered body so that nickel is not oxidized. Next, external electrodes 11 are formed on both end surfaces of the sintered body as shown in FIG. 2 and plated to obtain a finished product.

Table 1 shows a case where an adhesive layer is provided between a laminate block and a support as in the prior art and a case where an adhesive layer is provided between the laminate block and the support 7 as in the present embodiment. In the case where one ceramic sheet 1 is provided, the ease of separation of the laminate from the support after cutting and the number of structural defects after firing are shown in comparison.

[0018]

[Table 1]

As is clear from Table 1, the conventional method has a slightly lower separation rate from the support, and the laminate remains on the support. Also, the rate of occurrence of structural defects in the sintered body is slightly worse in the conventional method. As shown in FIG. 4, a crack 100 is generated on the side surface of the sintered body, and no pressure is applied to a portion where the internal electrode 3 is not provided when the second ceramic sheet 2 is crimped, as shown in FIG. It is thought that it became.

As described above, the laminate block and the support 7
By using the first ceramic sheet 1 having a high porosity in between, the separation from the support 7 can be performed more easily than in the past, and the structure due to the insufficient adhesive force between the second ceramic sheets 2 Defects can be suppressed, and the production yield can be greatly improved.

In this embodiment, the first ceramic sheet 1 has a weight average molecular weight of 40,000.
Using a dielectric powder containing polyethylene and barium titanate as main components and having a porosity of 70% and a thickness of 80 μm.
The first ceramic sheet 1 was used, but is not limited to this, and the weight average molecular weight of polyethylene is 40
The same effect can be obtained with a ceramic sheet having a porosity of 0000 or more and a porosity in the range of 30 to less than 80%.

In the present embodiment, only one first ceramic sheet 1 having a thickness of about 80 μm is used. However, a plurality of thin first ceramic sheets 1 may be used. I do not care. If the total thickness of one or a plurality of first ceramic sheets 1 interposed between the support 7 and the laminated block is 40 μm or more, the internal electrode forming portion 4 of the laminated block and the internal electrode non-forming portion 5 can be sufficiently absorbed, and cracks 1
The occurrence of structural defects such as 00 and delamination can be prevented.

Further, in the present embodiment, the hydrostatic press is performed to press the second ceramic sheets 2 together. However, as shown in FIG. 3, press plates 31 and 32 are provided on the upper and lower surfaces of the laminate block. May be provided, and the second ceramic sheets 2 may be pressed by uniaxial pressing. By simply providing the first ceramic sheet 1 between the press plate 31 on the lower surface to be pressed by the uniaxial press and the laminate block, after the laminate block is cut, the laminate can be easily separated into individual laminates and the presence or absence of the internal electrodes 3. Can be absorbed, but providing the first ceramic sheet 1 also between the press plate 32 on the upper surface and the laminate block has a further effect. However, in the hydrostatic press, a uniform pressure is applied to any part of the second ceramic sheet 2, so that the occurrence of laminating misalignment can be prevented.

Further, in the present embodiment, after the laminate block is cut, it is held in the atmosphere at 110 ° C. for about 15 minutes, but the softening point is higher than the melting point of the polyethylene contained in the first ceramic sheet 1 and lower than the melting point. (60 to 140 ° C.), the first ceramic sheet 1 shrinks, and the physical adhesion at the interface 6 between the first ceramic sheet 1 and the second ceramic sheet 2 is released. Can be separated into individual laminates.

In this embodiment, only the multilayer ceramic capacitor has been described. However, by using the manufacturing method of the present invention, other multilayer capacitors such as a multilayer varistor, a multilayer thermistor, a multilayer filter, a multilayer ferrite component, and a ceramic multilayer substrate can be obtained. A similar effect can be obtained for the ceramic electronic component of the mold.

[0026]

As described above, according to the present invention, after the laminate block is cut, the laminate can be easily separated into individual laminates, and burning such as cracks due to uneven pressing force due to the presence or absence of the conductive layer due to the presence or absence of the conductive layer. It is possible to suppress the occurrence of structural defects in the aggregate.

As a result, the yield can be greatly improved in the production of ceramic electronic components. In particular, there is a tremendous effect on the improvement of the yield of the multilayer ceramic capacitor which requires high lamination.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a crimping step of a multilayer ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a general multilayer ceramic capacitor.

FIG. 3 is a cross-sectional view illustrating a crimping step of a conventional multilayer ceramic capacitor.

FIG. 4 is a perspective view of a cracked sintered body.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 first ceramic sheet 2 second ceramic sheet 3 internal electrode 7 support 10 ceramic dielectric layer

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiro Komatsu 1006 Kazuma Kadoma, Kadoma City, Osaka Inside Matsushita Electric Industrial Co., Ltd. (56) References JP-A-3-276710 (JP, A) JP-A-5-205 190043 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 4/00-4/42

Claims (5)

(57) [Claims] 1. A first step of arranging at least one first ceramic sheet containing polyethylene and a ceramic raw material and having a porosity of 30% or more on a support, and then the first ceramic sheet A second step of forming a laminate block by laminating a plurality of second ceramic sheets on which a conductor layer of a desired shape is formed on the upper surface;
Next, after the laminate block pressure bonding, cut into a laminate of a desired shape, the softening point of the polyethylene or more, a third step of separating into individual laminates after maintaining the temperature below the melting point of the polyethylene, And thereafter, a fourth step of firing the laminate. 2. The method for manufacturing a ceramic electronic component according to claim 1, wherein the second ceramic sheet contains an organic component that is difficult to react with polyethylene. 3. The method for producing a ceramic electronic component according to claim 2, wherein polyvinyl butyral is used as the organic component that hardly reacts with polyethylene. 4. The method for manufacturing a ceramic electronic component according to claim 1, wherein the total thickness of the first ceramic sheet is 40 μm or more. 5. The temperature in the third step is 60 to 140.
The method for producing a ceramic electronic component according to any one of claims 1 to 4, wherein the temperature is set to ° C.