JP2002313673A - Method of manufacturing ceramic electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a ceramic electronic component having small probability of generating a short-circuit defect. SOLUTION: This method of manufacturing comprises a 1st step of reducing void fraction by compressing a ceramic sheet 10a containing ceramic powder and organic substances, 2nd step of forming a conductor layer 2 on the compressed ceramic sheet 10b by using a metallic paste, 3rd step of laminating a plurality of the ceramic sheets 10b on which the conductor layers are formed such that each conductor layer 2 mutually faces via the ceramic sheet 10b to obtain a laminate, and 4th step of firing the laminate. Since the conductor layer 2 is formed on the ceramic sheet 10b after reducing the void fraction, invasion of a metal component into the ceramic sheet 10b is suppressed.

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. 7 is a perspective view, partly in section, 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 ceramic sheet is formed by adding an organic substance to a dielectric powder mainly composed of barium titanate to be a ceramic dielectric layer 1, and a metal sheet to be a conductive layer 2 is formed thereon by a printing method. Print the paste into the desired shape. Next, a plurality of ceramic sheets on which the conductor layer 2 has been formed are laminated such that the conductor layers 2 alternately face each other with the ceramic sheet interposed therebetween to obtain a laminate. Thereafter, the laminate was fired to form external electrodes 3 on both end surfaces where the conductive layer 2 was exposed.

[0005]

However, according to the above method, when the porosity of the ceramic sheet is large, when the metal paste is directly printed on the ceramic sheet, the metal component penetrates into the inside of the ceramic sheet.

In recent years, multilayer ceramic capacitors have been made to have a thin ceramic sheet in order to achieve a high capacitance, and there is a problem that a short circuit occurs between the conductor layers 2 due to a metal component penetrating into the ceramic sheet. Had.

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

[0008]

In order to achieve this object, a method of manufacturing a ceramic electronic component according to the present invention comprises: pressing a ceramic sheet containing ceramic powder and an organic substance; A first step of heating the ceramic sheet to reduce the porosity, a second step of forming a conductor layer on the ceramic sheet by using a metal paste; A third step of obtaining a laminate by stacking a plurality of layers so that the layers face each other with the ceramic sheet interposed therebetween, and a fourth step of firing the laminate, and after reducing the porosity, Since the conductor layer is formed on the ceramic sheet, the intrusion of metal components into the ceramic sheet can be suppressed, and a short circuit between the conductor layers can be prevented. .

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention reduces the porosity by pressing a ceramic sheet containing a ceramic powder and an organic substance and heating the ceramic sheet to a temperature higher than the glass transition point of the organic substance and lower than its melting point. A first step, a second step of forming a conductor layer on the ceramic sheet by using a metal paste, and then separating the ceramic sheet on which the conductor layer is formed with the conductor layer sandwiching the ceramic sheet Third to obtain a laminate by laminating a plurality of sheets so as to face each other
And a fourth step of firing the laminated body. This is a method for manufacturing a ceramic electronic component, and a ceramic electronic component with few short-circuit defects can be obtained.

According to a second aspect of the present invention, there is provided a first step in which a ceramic sheet containing a ceramic powder and an organic substance is pressed and heated to a temperature equal to or higher than the glass transition point of the organic substance and lower than its melting point to reduce the porosity. A second step of forming a conductor layer on the body using a metal paste, a third step of forming a laminate in which the ceramic sheets and the conductor layers are alternately laminated, and This is a method for manufacturing a ceramic electronic component having a fourth step of firing, and a ceramic electronic component with few short-circuit defects can be obtained.

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

1 and 2 are partially enlarged cross-sectional views of a ceramic sheet according to an embodiment of the present invention. FIG. 3 is a cross-sectional view for explaining a process for obtaining the ceramic sheet shown in FIG. Ceramic sheet before decreasing the porosity, 10b ceramic sheet after decreasing the porosity, 11 ceramic particles, 12 polyethylene, 13
Is a gap, and 14a and 14b are rolls.

FIGS. 4 and 5 are cross-sectional views of a conductor layer according to an embodiment of the present invention. Reference numeral 2 denotes a conductor layer, and reference numeral 15 denotes a base film.

FIG. 6 is a cross-sectional view for explaining a manufacturing process for obtaining the conductor layer 2 shown in FIG.
a and 16b are rolls.

FIG. 7 is a sectional 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.

(Embodiment 1) First, the weight average molecular weight is 4
A ceramic sheet 10a having a thickness of 10 μm is prepared using 00000 polyethylene and a ceramic raw material powder containing barium titanate as a main component. The porosity of the ceramic sheet 10a is about 65%. FIG. 1 is a partially enlarged cross-sectional view showing the appearance of the ceramic sheet 10a, in which ceramic particles 11 are interspersed between fibers of polyethylene 12, and there are very many voids 13.

Next, as shown in FIG.
0a is passed between the rolls 14a and 14b having a smooth surface. At this time, the rolls 14a and 14b are rotating in opposite directions, and pressurize and heat the ceramic sheet 10a in the thickness direction. By performing heating in addition to pressurizing, the porosity of the ceramic sheet 10a can be easily reduced. That is, the heating increases the fluidity of the polyethylene 12 during pressurization, and the ceramic sheet 1
This is because the air inside the ceramic sheet 10a is removed from the inside of the ceramic sheet 10a to the outside, and at the same time, the filling property of the ceramic particles 11 increases. The heating temperature is desirably not less than the glass transition point of the polyethylene 12 and less than the melting point. Specifically, it is most suitable to carry out in the range of 60 ° C to 150 ° C. Here, the porosity of the ceramic sheet 10a may be improved by a uniaxial press in the thickness direction using a press plate instead of the rolls 14a and 14b. In the present embodiment, rolls 14a and 14b are used because they can be continuously processed.

In this embodiment, 40%, 30%
%, 20%, and 10% of the ceramic sheet 10b having four types of porosity. FIG. 2 shows a partially enlarged cross-sectional view of the ceramic sheet 10b after pressing and heating. As can be seen from this figure, the gap 13 is reduced.

Next, 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 to reduce the porosity. Ceramic sheet 10
On b, a metal paste is printed in a desired shape and dried to form a plurality of conductor layers 2 having a thickness of 2.5 μm.

Next, after stacking a plurality of ceramic sheets 10b on which the conductor layer 2 is not formed to form an ineffective layer, a desired number of ceramic sheets 10b having the conductor layer 2 formed on the ineffective layer are formed. The temporary laminated body is obtained by laminating and further forming an invalid layer thereon. At this time, as the ceramic sheet on which the conductor layer 2 is not formed, either the ceramic sheet 10a whose porosity is not reduced or the ceramic sheet 10b whose porosity is reduced may be used. When the porosity of the ceramic sheet is less than 20%, or when the porosity of the ceramic sheet is
A better laminate can be obtained by using. The reason is that the ceramic sheet 10a alleviates the uneven pressing force between the portion where the conductive layer 2 is formed and the portion where the conductive layer 2 is not formed in the temporary laminate during pressing.
In the present embodiment, the laminated body of the ceramic sheet 10b on which the conductor layer 2 is formed is 150 layers, and the ineffective layer is a ceramic sheet 10a with reduced porosity.

Next, the entire temporary laminate is pressed, cut into a laminate of a desired shape, degreased, and then fired. It is desirable that the degreasing be performed in the order of removing the plasticizer from the laminate while raising the temperature of the laminate in the air, and further increasing the temperature to remove the binder. The reason is that when heated at once to remove the plasticizer and the binder at once, a new compound is generated by the plasticizer and the binder and remains in the laminate even after degreasing, and this compound burns 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 degreasing and subsequent firing are performed on the conductive layer 2.
The conditions are set so that the nickel is not excessively oxidized. By sintering, a sintered body is obtained in which the ceramic laminate 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, and after plating (not shown), a multilayer ceramic capacitor shown in FIG. 7 is obtained.

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

[0023]

[Table 1]

The conventional product 1 is manufactured by the above method using the ceramic sheet 10a in which the porosity of the ceramic sheet 10a forming the conductor layer 2 is not reduced. As is clear from Table 1, the short-circuit rate of the product of the present embodiment is smaller than that of the conventional product 1. In addition, as a result of analyzing the internal cross section of the product in which the short-circuit failure occurred, it was clarified that the short-circuit location was a short-circuit between the conductor layers 2.

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

In particular, the high-molecular polyethylene used as a binder as in the present embodiment tends to be bulky and have a high porosity as compared with a polyvinyl butyral resin or an acrylic resin. Therefore, reducing the porosity before forming the conductor layer 2 as in the present invention is very effective in reducing short-circuit defects.

(Embodiment 2) In Embodiment 1, the conductor layer 2 is formed by printing a metal paste directly on the ceramic sheet 10a having a reduced porosity. However, in this embodiment, the conductor layer is formed. 2 is formed on a base film 15 such as a polyethylene terephthalate film.

First, the porosity of the ceramic sheet 10a is reduced to 40% and 30% in the same manner as in the first embodiment.
The ceramic sheet 10b having four types of porosity of%, 20%, and 10% is prepared.

Also, as shown in FIG. 4, the conductor layer 2 is printed on the base film 15 in a desired shape using the same metal paste as in the first embodiment, dried, and most of the solvent is scattered. The surface is hardened so that it is almost exclusively the metal component and the plasticizer and binder components. Specifically, the organic component in the conductor layer 2 is 5 to 100% by weight of the metal component.
The content is 15 wt%, preferably 8 to 12 wt%. The reason is that if it is less than 5 wt%, the adhesion to the ceramic sheet 10 b will be poor, and if it exceeds 15 wt%, the stickiness of the conductor layer 2 will be excessive, and the conductor layer 2 having a desired shape cannot be produced. Because.

At this time, an acrylic resin, a melamine resin, or the like is previously placed on the base film 15 so that the conductive layer 2 and the base film 15 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) made of at least one of epoxy resin and silicon resin. In particular, a desired release property can be obtained in a mixed system of an acrylic resin and a melamine resin.
In addition, silicone resin is effective in that desired release properties can be obtained and solvent resistance and moisture resistance are excellent.

Next, a plurality of ceramic sheets 10a on which the conductor layer 2 is not formed are laminated on the support to form an ineffective layer.
After lamination such that the conductor layer 2 is in direct contact with the ceramic sheet 10b, pressure is applied from above and below to bond the conductor layer 2 and the ceramic sheet 10b. This pressurization is desirably performed in a temperature range from room temperature to a temperature (150 ° C. in the present embodiment) at which the plasticizer in the conductor layer 2 does not scatter too much. The reason is that if the plasticizer is scattered too much, the conductor layer 2 becomes hard and brittle, and the ceramic sheet 1
This is because the adhesive force between Ob and the conductive layer 2 decreases, and structural defects occur during lamination or firing. Therefore, by performing in the above temperature range, the binder component and the plasticizer component contained in the conductor layer 2 can be softened, and the adhesiveness between the conductor layer 2 and the ceramic sheet 10b can be improved.

When the contents of the plasticizer and the binder in the conductor layer 2 are low, the plasticizer and the binder are activated by increasing the temperature at the time of pressurization so that the conductor layer 2 and the ceramic sheet 10b can be activated. Improves adhesion. On the other hand, when the content is high, the adhesiveness between the conductor layer 2 and the ceramic sheet 10b 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.

Next, the base film 15 is released, and the ceramic sheet 10b is laminated on the conductor layer 2. Thereafter, the conductor layer 2 together with the base film 15 is again laminated on the ceramic sheet 10b and pressed under the above conditions. The lamination of the ceramic sheet 10b and the conductor layer 2 is repeated a desired number of times, and an ineffective layer is formed thereon using the ceramic sheet 10a to obtain a temporary laminate.

Thereafter, a multilayer ceramic capacitor having 150 effective layers is manufactured in the same manner as in the first embodiment.

Table 2 shows the short-circuit rate of the multilayer ceramic capacitor in comparison with the product of the present embodiment and the conventional product 2.

[0036]

[Table 2]

The conventional product 2 is manufactured by the above method using the ceramic sheet 10a whose porosity is not reduced. As is clear from (Table 2), it can be seen that the product of the present embodiment has a reduced short-circuit rate as compared with Conventional Product 2. Further, it can be seen that the short-circuit rate is lower than that of the first embodiment. This is because the porosity is reduced and the dried conductor layer 2 is placed on the ceramic sheet 10b.
Is transferred, so that the penetration of the metal component into the ceramic sheet 10b is further suppressed.

Therefore, according to the present embodiment, the penetration of the metal component into the ceramic sheet 10b is prevented in the first embodiment.
It is possible to further reduce the short-circuit between the conductor layers 2 and significantly improve the yield.

In the present embodiment, when the ceramic sheets 10b are alternately laminated with the conductor layers 2, the ceramic sheets 10b may be pressurized each time one layer is laminated. The layers are simply laminated, and when the conductor layer 2 formed on the base film 15 is laminated thereon and then pressed, the adhesion between the ceramic sheets 10b and between the ceramic sheet 10b and the conductor layer 2 is simultaneously secured. It does not matter. However, in the latter case, the number of times of pressurization is halved compared to the former. This pressurizing process requires a time of about 1 to 30 seconds / time, and the longer the number of laminations, the more time it takes. This contributes to the increase in cost of the multilayer ceramic capacitor. In particular, when the conductor layer 2 is formed of a base metal, the ratio of the lamination process to the product price is large. Therefore, when the temporary laminate is manufactured, the ceramic sheet 10b is simply laminated, and the base film is formed thereon. When the conductor layer 2 formed on the ceramic sheet 15 is pressed after lamination, the ceramic sheet 1
By simultaneously securing the adhesiveness between 0b and between the ceramic sheet 10b and the conductor layer 2, it is possible to contribute to cost reduction.

In this embodiment, the conductive layer 2
Since the number of stacked layers is 100 or more, the ineffective layer used was a ceramic sheet 10a whose porosity was not reduced.

(Embodiment 3) In Embodiment 3, the conductor layer 2 formed on the base film 15 as shown in FIG. 4 is superposed together with the base film 15 so as to be in contact with the ceramic sheet 10b. A ceramic sheet 10b with a body layer 2 is prepared, and this is laminated to produce a laminated body.

More specifically, a ceramic sheet 10b having a reduced porosity manufactured in the same manner as in the first and second embodiments.
The ceramic sheet 10b and the conductor layer 2 are brought into close contact with each other by sandwiching the base film 15 and the conductor layer 2 formed on the base film 15 together with the base film 15 between rollers. The temperature at the time of pressurization is set in a range from room temperature to a temperature at which the plasticizer in the conductor layer 2 does not scatter too much, similarly to the second and third embodiments.

In this manner, the conductor layer 2 and the ceramic sheet 10b are formed on the base film 15, cut into a desired shape, and then sequentially laminated and pressed to laminate a desired number of sheets. Obtain a laminate.

The formation of the temporary laminate is described in the first and second embodiments.
On the same ineffective layer as described above, lamination is performed so that the base film 15 is on the upper side, and peeling of the base film 15 after pressing is repeated. It may be performed by repeating lamination and pressurization of the ceramic sheet 10b.

However, when the base layer 15 is removed and the conductive layer 2 is laminated so as to be on top of the base film 15, the conductive layer 2 may be pressed with a pressing device such as a press plate. It is important to provide a sheet so that the conductive layer 2 does not adhere between the plates. Therefore, when laminating after peeling off the base film 15, it is desirable that the ceramic sheet 16 be on top.

Thereafter, a multilayer ceramic capacitor is obtained in the same manner as in the first embodiment. In addition, when the ceramic sheet 10b with the conductor layer 2 is manufactured using the roller as described above, it can be performed at a relatively high speed.
That is, in the third embodiment, the number of times of pressing at the time of lamination is reduced by half as compared with the case where the pressing is performed each time the ceramic sheet 10b and the conductor layer 2 are stacked as described in the second embodiment. Can contribute to cost reduction.

Table 3 shows the short-circuit rate of the multilayer ceramic capacitor in which the number of effective layers (the number of ceramic dielectric layers 1 sandwiched between the conductor layers 2) is 150, in this embodiment and the conventional product. 3 is shown in comparison with FIG.

[0048]

[Table 3]

The conventional product 3 is manufactured by the above method using the ceramic sheet 10a before the porosity is reduced. As is clear from Table 3, the short-circuit rate of the product of the present embodiment is drastically reduced as compared with the conventional product 3. Further, as a result of analyzing the internal cross section of the short-circuited product, the short-circuited portion was a short-circuit between the conductor layers 2.

Thus, according to the present embodiment, the short circuit between the conductor layers 2 can be drastically reduced, the yield can be greatly improved, and the cost can be reduced.

(Embodiment 4) In Embodiment 4, too, the conductor layer 2 is not formed directly on the ceramic sheet 10b, but is formed on a base film 15 such as a polyethylene terephthalate film.

First, the porosity of the ceramic sheet 10a is reduced to 40% and 30% in the same manner as in the first embodiment.
The ceramic sheet 10b having four types of porosity of%, 20%, and 10% is prepared.

The conductive layer 2 is printed in a desired shape on the base film 15 using a metal paste and dried in the same manner as in the first embodiment, and most of the solvent is scattered to harden the surface. Components and only plasticizer and binder components. Specifically, the organic component in the conductor layer 2 is set to 5 to 15 wt%, preferably 8 to 12 wt% with respect to 100 wt% of the metal component. The reason is 5w
If the amount is less than t%, the adhesion to the ceramic sheet 10b will be poor, and if it exceeds 15% by weight, the stickiness of the conductor layer 2 will be excessive, and the conductor layer 2 having a desired shape cannot be produced. .

At this time, in order to easily release the conductive layer 2 and the base film 15 in a later step, an acrylic resin, a melamine resin,
It is desirable to print the conductor layer 2 after forming a release layer (not shown) made of at least one of epoxy resin and silicon resin. Particularly, in a mixed system of an acrylic resin and a melamine resin, a desired release property can be obtained. In addition, silicone resin is effective in that desired release properties can be obtained and solvent resistance and moisture resistance are excellent. At this time, the surface of the conductor layer 2 is in a state of having irregularities on the surface as shown in FIG.

Next, after the conductive layer 2 is dried, the base film 15 and the conductive layer 2 are passed between the rolls 16a and 16b having a smooth surface as shown in FIG.
By pressing the conductor layer 2 in the thickness direction at 6b, the irregularities on the surface of the conductor layer 2 are reduced. FIG. 5 is a sectional view of the conductor layer 2 having a smooth surface.

Next, a plurality of ceramic sheets 10a on which the conductor layer 2 is not formed are laminated on the support to form an ineffective layer.
After laminating the conductor layer 2 so as to make direct contact with the ceramic sheet 10b, pressure is applied from the thickness direction to adhere the conductor layer 2 and the ceramic sheet 10b. This pressurization is desirably performed in a temperature range from room temperature to a temperature (150 ° C. in the present embodiment) at which the plasticizer in the conductor layer 2 does not scatter too much. 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 10b and the conductor layer 2 decreases, and structural defects occur during lamination or firing. . Therefore, 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 10b can be improved.

When the contents of the plasticizer and the binder in the conductive layer 2 are low, the plasticizer and the binder are activated by increasing the temperature at the time of pressurization, so that the conductive layer 2 and the ceramic sheet 10b are joined together. Improve the adhesiveness of On the other hand, when the content is high, the adhesiveness between the conductor layer 2 and the ceramic sheet 10b 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 according to the type and content of the organic component in the conductor layer 2.

Next, the base film 15 is released, and the ceramic sheet 10 b is laminated on the conductor layer 2. Thereafter, the conductor layer 2 together with the base film 15 is again laminated on the ceramic sheet 10b, and the above conditions are applied. The lamination of the ceramic sheet 10b and the conductor layer 2 is repeated a desired number of times to obtain a temporary laminate. Thereafter, a multilayer ceramic capacitor having 150 effective layers is manufactured in the same manner as in the first embodiment.

Table 4 shows the short-circuit rate of the multilayer ceramic capacitor in comparison with the product of the present embodiment and the conventional product 4.

[0060]

[Table 4]

The conventional product 4 is manufactured by using the ceramic sheet 10a whose porosity is not reduced by the method described in the second embodiment. As is clear from Table 4, the short-circuit rate of the product of the present embodiment is smaller than that of the conventional product 4. Further, Embodiment 2
It can be seen that the short-circuit rate is low even when compared with. This is because not only the porosity is reduced, but also the conductor layer 2 is transferred after drying on the ceramic sheet 10b as well as the surface of the conductor layer 2 is transferred after reducing the unevenness. This is because the penetration of the metal component into the ceramic sheet 10b due to the protrusion of the conductor layer 2 piercing can be further suppressed.

From this, according to the present embodiment, the penetration of the metal component into the ceramic sheet 10b is prevented according to the second embodiment.
It is possible to further reduce the short-circuit between the conductor layers 2 and significantly improve the yield.

The method of forming the laminate is described in the second embodiment.
May be performed by alternately laminating the ceramic sheet 10b and the conductor layer 2 as shown in FIG. 7, or the ceramic sheet 10b with the conductor layer 2 as in the third embodiment.
May be formed and laminated. In any case, not only the effects of the second and third embodiments but also the short-circuit failure can be reduced.

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

(1) The present invention has a particularly remarkable effect when the porosity of the ceramic sheet 10a before the porosity reduction is 50% or more.

(2) When polyethylene is contained in the ceramic sheets 10a and 10b as in the above embodiments,
If the porosity is reduced without heating, if the porosity is reduced without heating, if the porosity is reduced without heating, the air enters into the ceramic sheet 10b and increases the porosity. It is preferred to carry out immediately. When heating, the porosity does not change significantly even if the polyethylene is left for a long time because the polyethylene is plastically deformed.

(3) The elasticity is improved by reducing the porosity of the ceramic sheet 10a, and the elongation of the ceramic sheet 10b can be prevented in the manufacturing process.

(4) When pressure is applied in the thickness direction of the ceramic sheet 10a in order to reduce the porosity of the ceramic sheet 10a, the unevenness of the surface of the ceramic sheet 10b on which the conductor layer 2 is formed can be reduced. Therefore, it is possible to easily form the conductor layer 2 on the ceramic sheet 10b.

(5) When pressurization and heating at a temperature equal to or higher than the glass transition point of the organic substance and lower than the melting point are performed when reducing the porosity of the ceramic sheet 10a, it is desirable to perform the pressurization simultaneously or first. In particular, when reducing the porosity of the ceramic sheet 10a using polyethylene, it is necessary to perform the pressing and the heating simultaneously or first. The reason is,
When heated at a temperature higher than the glass transition point of the polyethylene and less than the melting point in the absence of pressure, the polyethylene shrinks and shrinks in the width direction of the ceramic sheets 10a and 10b, so that wrinkles are generated and the ceramic sheet having a uniform thickness. 10b
Because you cannot get

(6) By setting the porosity of the ceramic sheet 10b having a reduced porosity to be less than 50%, the metal component in the conductor layer 2 is reduced to a value less than 50%.
The effect of suppressing intrusion into the inside is remarkable. However, even if the porosity is too low, it is not possible to absorb the step between the portion where the conductor layer 2 is formed and the portion where the conductor layer 2 is not formed when forming the temporary laminate and the laminate, and a structural defect is generated. Is desirably 10% to 40%.

(7) The pressing force for producing the ceramic sheet 10b with reduced porosity is not more than the pressing force for pressing the entire temporary laminate, preferably smaller than the pressing force for the temporary laminate. desirable. The reason is that if the porosity of the ceramic sheet 10b before producing the temporary laminate becomes too low, it is not possible to absorb the step between the portion where the conductor layer 2 is formed and the portion where the conductor layer 2 is not formed, and a structural defect occurs. Because you do.

(8) In the case where heat treatment is performed in a process until a temporary laminate is obtained using the ceramic sheets 10a and 10b containing an organic binder, heat treatment is performed in a temperature range from the glass transition point of the organic binder to the melting point. Thereby, the fluidity of the polyethylene is improved, and the heat treatment effect becomes remarkable.

(9) In the above embodiments, the multilayer ceramic capacitor has been described, but a ceramic electronic component formed by laminating a ceramic sheet and a conductor layer such as a multilayer varistor, a multilayer thermistor, a multilayer coil, and a ceramic multilayer substrate. Has the same effect.

[0074]

As described above, according to the present invention, the penetration of metal components in the conductor layer into the ceramic sheet can be suppressed to a minimum by previously reducing the porosity of the ceramic sheet. Is extremely suppressed, and the yield can be improved.
In particular, the ceramic sheet is thin, and has a great effect on the improvement of the yield of the multilayer chip capacitor which requires high lamination.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view of a ceramic sheet before a porosity is reduced according to an embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of a ceramic sheet after a porosity is reduced in one embodiment of the present invention.

FIG. 3 is a sectional view illustrating a manufacturing process for obtaining the ceramic sheet shown in FIG. 2;

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

FIG. 5 is a cross-sectional view of a conductor layer after a smoothing process according to one embodiment of the present invention.

6 is a cross-sectional view for explaining a manufacturing process for obtaining the conductor layer shown in FIG.

FIG. 7 is a partial cross-sectional perspective view of a general multilayer ceramic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ceramic dielectric layer 2 Conductive layer 3 External electrode 10a Ceramic sheet 10b Ceramic sheet 11 Ceramic particles 12 Polyethylene 13 Void 14a Roll 14b Roll 15 Base film 16a Roll 16b Roll

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hideki Kuramitsu 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5E082 AB03 BC36 EE04 EE35 FG06 FG26 FG54 LL01 MM22 PP06

Claims (2)

[Claims] A first step of pressing a ceramic sheet containing a ceramic powder and an organic substance and heating the ceramic sheet to a temperature equal to or higher than the glass transition point of the organic substance and lower than its melting point to reduce the porosity;
Next, a second step of forming a conductor layer on the ceramic sheet using a metal paste, and then forming a plurality of ceramic sheets on which the conductor layer is formed so that the conductor layers face each other with the ceramic sheet interposed therebetween. A method for manufacturing a ceramic electronic component, comprising: a third step of obtaining a laminate by stacking a plurality of sheets; and a fourth step of firing the laminate. 2. A first step of pressing a ceramic sheet containing a ceramic powder and an organic substance and heating the ceramic sheet to a temperature equal to or higher than the glass transition point of the organic substance and lower than its melting point to reduce the porosity;
A second step of forming a conductor layer using a metal paste on the support; and a third step of forming a laminate in which the ceramic sheet and the conductor layer are alternately laminated, and
And a fourth step of firing the laminated body.