JP2001110669A - Method for manufacturing ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ceramic electronic component of little short-circuit failure by suppressing infiltration of metal components into a ceramic sheet. SOLUTION: A ceramic sheet 10 is prepared where polyethylene 12 has a network structure with an organic substance and ceramic powder 11 present in a layered form. A conductor layer is formed on a base film and transferred onto the ceramic sheet 10 to produce a ceramic sheet with the conductor layer. Then, the ceramic sheet with the conductor layer is stacked to produce a laminate, and an external electrode is formed after burning.

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. 5 is a partially cutaway perspective view of a general multilayer ceramic capacitor, wherein 1 is a ceramic dielectric layer,
2 is a conductor layer, 3 is an external electrode, and one end of the conductor layer 2 is connected to the external electrode 3 at an end of the ceramic dielectric layer 1.

Hereinafter, a method for manufacturing a conventional multilayer ceramic capacitor will be described.

[0004] First, a slurry prepared by adding an organic substance to a dielectric powder containing barium titanate as a main component and serving as a ceramic dielectric layer 1 is processed into a sheet to form a ceramic sheet, on which a conductor is formed. The metal paste to be the layer 2 is printed in a desired shape.

Next, a plurality of ceramic sheets on which the conductor layers 2 are formed are laminated so that the conductor layers 2 alternately face each other with the ceramic sheets interposed therebetween to obtain a laminate. afterwards,
This laminate was fired to form external electrodes 3 on both end surfaces where the conductive layer 2 was exposed.

[0006]

However, according to the above-described method, since a ceramic sheet has a large number of through-pin holes, when a metal paste is printed on that portion, a metal component penetrates the ceramic sheet, There is a problem that a short circuit occurs.

Accordingly, an object of the present invention is to provide a method of manufacturing a ceramic electronic component with less short-circuit defects.

[0008]

In order to achieve the above object, a method of manufacturing a ceramic electronic component according to the present invention is directed to a method of manufacturing a ceramic electronic component, comprising the steps of alternately stacking a ceramic sheet containing an organic substance and ceramic powder and a conductor layer. And a second step of firing the laminated body, wherein the organic sheet has a network structure and the organic substance and the ceramic powder are present in a layered form. It is used, and even if there is a pinhole in one layer of the layered structure, since it is formed of many layers of organic substances and ceramic powder, it is difficult to generate a pinhole such that a metal component penetrates the ceramic sheet. Things.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention comprises a first step of alternately laminating a ceramic sheet containing an organic substance and ceramic powder and a conductor layer to form a laminate, Next, a second step of firing the laminate is provided, wherein the organic material has a network structure and the organic material and the ceramic powder are present in layers as the ceramic sheet. In addition, since a metal component can be prevented from penetrating the ceramic sheet, a ceramic electronic component with few short-circuit defects can be obtained.

According to a second aspect of the present invention, there is provided the method for manufacturing a ceramic electronic component according to the first aspect, wherein the porosity of the ceramic sheet is less than 50%, and a metal component is suppressed from penetrating the ceramic sheet. be able to.

According to a third aspect of the present invention, in the first step, a conductive layer formed on a base film is laminated on a ceramic sheet to peel off the base film, and a ceramic layer is formed on the conductive layer. 2. The method for manufacturing a ceramic electronic component according to claim 1, wherein the step of laminating the sheets is repeated, and the solvent component in the conductor layer is reduced as compared with the case where the dielectric layer is directly formed on the ceramic sheet. Therefore, intrusion of the metal component into the ceramic sheet can be suppressed.

According to a fourth aspect of the present invention, there is provided the method for manufacturing a ceramic electronic component according to the third aspect, further comprising the step of pressing the conductor layer in the thickness direction before laminating the conductor layer on the ceramic sheet. By reducing unevenness on the surface of the layer, it is possible to suppress intrusion of the metal component into the ceramic sheet.

According to a fifth aspect of the present invention, there is provided the method of manufacturing a ceramic electronic component according to the first aspect, wherein the conductive layer is formed by a thin film forming method in the first step. Therefore, intrusion of the metal component into the ceramic sheet can be suppressed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings, taking a multilayer ceramic capacitor as an example.

FIG. 1 is an enlarged longitudinal sectional view of a main part of a ceramic sheet according to one embodiment of the present invention, FIG. 2 is a transverse sectional view of the same, 10 is a ceramic sheet, 11 is a ceramic powder, 12 is polyethylene, and 13 is a polyethylene. It is a void.

FIGS. 3 and 4 are cross-sectional views of a conductor layer according to an embodiment of the present invention. Reference numeral 2 denotes a conductor layer, and 14 denotes a base film.

FIG. 5 is a partially cutaway perspective view of a general multilayer ceramic capacitor, wherein 1 is a ceramic dielectric layer, 2 is a conductor layer, and 3 is an external electrode.

First, a ceramic sheet 10 having a porosity of less than 50% is prepared using polyethylene having a weight average molecular weight of 400,000 or more and a ceramic raw material powder containing barium titanate as a main component. As shown in FIGS. 1 and 2, a polyethylene 12 having a network structure as an organic substance is in a layered form, and the ceramic powder 11 is adsorbed on the network, and the ceramic powder 11 is also a layered structure having a network structure. . Further, since the polyethylene 12 having a mesh structure is not regularly arranged, the ceramic sheet 10
When viewed from the upper surface, there is almost no gap 13 penetrating the ceramic sheet 10.

A metal paste containing nickel as a metal component, ethyl cellulose, an acrylic resin, a butyral resin as a binder, benzyl butyl phthalate as a plasticizer, and an aliphatic or aromatic solvent as a solvent is prepared, and a polyethylene terephthalate film or the like is prepared. A plurality of conductor layers 2 are formed on the base film 14 of FIG. At this time, the conductor layer 2 has irregularities on the surface as shown in FIG. Therefore, as shown in FIG. 4, it is desirable to reduce irregularities on the surface of the conductor layer 2 to suppress the conductor layer 2 from entering the ceramic sheet 10.

At this time, at least one of an acrylic resin, a melamine resin, an epoxy resin, and a silicone resin is formed on the base film 14 in advance so that the conductive layer 2 and the base film 14 can be easily released from the mold in a later step. It is desirable to print the conductor layer 2 after forming a release layer (not shown) of at least one kind. In particular, in a mixed system of an acrylic resin and a melamine resin, a desired release property can be obtained. In addition, the silicone resin is effective in that desired release properties can be obtained and the solvent resistance and moisture resistance are excellent.

Next, the conductor layer 2 is laminated on the ceramic sheet 10 together with the base film 14 so that the conductor layer 2 comes into contact with the ceramic sheet 10.
After applying pressure from above to transfer the conductor layer 2 to the ceramic sheet 10, the base film 14 was peeled off to produce a ceramic sheet with a conductor layer.

Next, a plurality of ceramic sheets 10 are stacked to form an ineffective layer, a desired number of ceramic sheets with a conductor layer are stacked on the ineffective layer, and an ineffective layer is further formed thereon to temporarily laminate the ineffective layer. Get the body.

Thereafter, the entire temporary laminate is pressed, cut into a laminate of a desired shape, degreased, and fired. The degreasing is preferably performed in the order of removing the plasticizer in the laminate while raising the temperature of the laminate in the air or nitrogen, and then further removing the binder by further increasing the temperature. The reason is that if heated at once to remove the plasticizer and the binder at once, a new compound will be generated by the plasticizer and the binder and will remain in the laminate even after degreasing, and this compound will burn during firing. This is because structural defects such as delamination occur by being removed from the laminate, and the occurrence rate of short-circuit defects increases.

Further, conditions for the degreasing and the subsequent baking are set so that nickel which will be the conductor layer 2 is not excessively oxidized. By sintering, a sintered body is obtained in which the ceramic dielectric layer 1 mainly containing barium titanate and the conductor layer 2 mainly containing nickel are sintered.

Next, external electrodes 3 made of copper or the like are baked on the exposed both end surfaces of the conductor layer 2 of the sintered body, plated (not shown), and the multilayer ceramic capacitor shown in FIG. 5 is obtained.

Table 1 shows the number of short-circuits of the multilayer ceramic capacitor in which the number of effective layers (the number of ceramic dielectric layers 1 sandwiched between the conductive layers 2) is 150, in this embodiment and the conventional product. It is shown in comparison with.

[0027]

[Table 1]

The conventional product 1 uses a ceramic sheet having no layered structure manufactured using a conventional slurry.

As is clear from Table 1, the number of short-circuits of the product of this embodiment is smaller than that of the conventional product. In addition, as a result of analyzing the internal cross section of the short-circuit failure product, it was found that the short-circuited portion was a short-circuit between the conductor layers 2.

Therefore, according to the present embodiment, the penetration of the metal component in the conductor layer 2 into the ceramic sheet 10 is suppressed, the short circuit between the conductor layers 2 is drastically reduced, and the yield is greatly improved. be able to.

Hereinafter, the points of the present invention will be described.

(1) By setting the porosity of the ceramic sheet 10 when laminated with the conductor layer 2 to be less than 50%, penetration of metal components in the conductor layer 2 can be suppressed. For the ceramic sheet 10 of 50% or more, the porosity may be adjusted to less than 50% by pressing in the thickness direction, and then laminated with the conductor layer 2.

However, if the porosity is too low, it is not preferable because the pressure difference between the portion where the conductive layer 2 is formed and the portion where the conductive layer 2 is not formed cannot be absorbed when the laminate is pressed.

Therefore, it is preferable that the porosity is not less than 10% and less than 50%.

(2) The conductor layer 2 is made of a ceramic sheet 10
May be formed by directly printing a metal paste on the ceramic sheet 10, but it is better to form the metal paste on the base film 14, and then transfer it to the ceramic sheet 10 after drying. Hard to penetrate inside.

In this case, the conductor layer 2 is pressed in the thickness direction before lamination on the ceramic sheet 10 to reduce the unevenness on the surface of the conductor layer 2, so that the metal component on the ceramic sheet 10 can be reduced. Infiltration can be further suppressed.

(3) The conductor layer 2 may be formed directly on the ceramic sheet 10 by a thin film forming method such as vapor deposition or sputtering. In this case, since the metal components are integrated into a plate shape, the penetration of the metal components into the ceramic sheet 10 can be suppressed.

(4) The pressure applied until the entire temporary laminated body is pressurized is from room temperature to a temperature (150 ° C. in the present embodiment) at which the plasticizer in the conductive layer 2 does not scatter too much. It is desirable to perform in the temperature range. The reason is that if the plasticizer is scattered too much, the conductor layer 2 becomes hard and brittle, the adhesive force between the ceramic sheet 10 and the conductor layer 2 decreases, and structural defects occur during lamination or firing. . Further, by performing the heat treatment in the above temperature range, the binder component and the plasticizer component contained in the conductor layer 2 can be softened, and the adhesion between the conductor layer 2 and the ceramic sheet 10 can be improved. When the content of the plasticizer and the binder in the conductor layer 2 is low, the plasticizer and the binder are activated by increasing the temperature at the time of pressurization, so that the adhesion between the conductor layer 2 and the ceramic sheet 10 is increased. Improve. On the other hand, when the content is high, the adhesiveness between the conductive layer 2 and the ceramic sheet 10 can be sufficiently obtained even at room temperature, so that it is not necessary to heat. That is, it is preferable to adjust the heating temperature in accordance with the type of the organic component in the conductor layer 2 and the content thereof.

(5) In the above embodiment, the multilayer ceramic capacitor has been described.
Similar effects can be obtained in a ceramic electronic component formed by laminating a ceramic sheet and a conductor layer, such as a laminated thermistor, a laminated coil, and a ceramic multilayer substrate.

[0040]

According to the present invention described above, a ceramic electronic component with few short-circuit defects can be obtained by suppressing the penetration of the metal component in the conductor layer into the ceramic sheet.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a ceramic sheet according to an embodiment of the present invention.

FIG. 2 is an enlarged top view of the ceramic sheet shown in FIG.

FIG. 3 is a cross-sectional view of a conductor layer according to one embodiment of the present invention.

FIG. 4 is a cross-sectional view of a conductor layer according to one embodiment of the present invention.

FIG. 5 is a partially cutaway perspective view of a general multilayer ceramic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic dielectric layer 2 Conductive layer 3 External electrode 10 Ceramic sheet 11 Ceramic powder 12 Polyethylene 13 Void 14 Base film

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Hideki Kuramitsu 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. AA01 AB03 BC33 BC36 BC38 EE04 EE05 EE23 EE35 EE37 FG06 FG26 FG54 GG10 GG11 GG26 GG28 HH43 JJ03 JJ05 JJ21 JJ23 LL02 LL03 LL35 MM22 PP10

Claims (5)

[Claims] 1. A first step of alternately laminating ceramic sheets containing an organic substance and ceramic powder and a conductor layer to form a laminate, and then a second step of firing the laminate. A method of manufacturing a ceramic electronic component, wherein the ceramic sheet has a network structure of the organic substance and the organic substance and the ceramic powder are present in layers. 2. The method according to claim 1, wherein the porosity of the ceramic sheet is less than 50%. 3. The first step includes a step of laminating a conductor layer formed on a base film on a ceramic sheet and peeling off the base film, and a step of laminating a ceramic sheet on the conductor layer. The method for manufacturing a ceramic electronic component according to claim 1, wherein the method is repeated. 4. The method for manufacturing a ceramic electronic component according to claim 3, further comprising a step of pressing the conductor layer in a thickness direction before laminating the conductor layer on the ceramic sheet. 5. The method according to claim 1, wherein the conductive layer is formed by a thin film forming method in the first step.