JPH10284338A - Electronic component of laminated ceramic and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable electronic component of laminated ceramic capable of improving the sealability of the ceramic laminate. SOLUTION: Extraction electrodes 6 and 7 connected to the internal electrodes 4 and 5, and extended to external faces 8 and 9 of a laminate 3, are comprised by a conductive paste containing resin to improve the sealability of the ceramic laminate 3. As a conductive paste, the material, for instance, 10 to 30 wt.% of polyimide resin and 70 to 90 wt.% of metal powder are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic electronic component and a method of manufacturing the same, and more particularly, to an internal electrode formed inside a ceramic laminate provided in a multilayer ceramic electronic component and an external electrode formed on an outer surface. The present invention relates to a connection structure with an electrode and a method for obtaining the connection structure.

[0002]

2. Description of the Related Art A multilayer ceramic electronic component such as a multilayer ceramic capacitor includes a ceramic laminate including laminated ceramic layers. Internal electrodes are formed inside the ceramic laminate so as to extend along interfaces between specific ceramic layers. Similarly, an extraction electrode is formed along the interface between the ceramic layers on which the internal electrode is formed and connected to the internal electrode and extending to the end of the interface. In a normal multilayer ceramic capacitor, these internal electrodes and lead electrodes are formed of a series of conductive films.

An external electrode is formed on the outer surface of the ceramic laminate so as to be electrically connected to the above-mentioned extraction electrode. The external electrode is generally formed by applying a paste containing glass frit and metal powder on the outer surface of the ceramic laminate and baking the paste. Further, on the external electrodes described above, the solderability is improved, the adhesion with the external electrodes and the adhesion between the films are improved, or when the external electrodes contain Ag, the solder erosion of Ag is suppressed. For the purpose of forming a film made of solder or tin by electroplating,
Or, usually, a film made of Cu or the like is formed by electroplating, and then a film made of solder or tin is formed by electroplating.

[0004]

However, since the external electrodes formed by baking as described above are relatively porous, in this plating step, the plating solution may penetrate into the ceramic laminate through the external electrodes. There is. As described above, when the plating solution enters the ceramic laminate, the obtained multilayer ceramic capacitor deteriorates the insulation resistance (IR), the moisture resistance characteristic, and the like, and peels off the ceramic layers included in the ceramic laminate. Or inconveniences.

Conventionally, the disadvantage that the external electrode is porous as described above is because the glass frit contained in the paste for forming the external electrode acts to fill the pores present in the external electrode at the time of baking. The solution is usually attempted. However, depending on the type and particle size of the glass frit, or the baking conditions, etc., the pores of the external electrode may not be sufficiently filled with glass, that is, the external electrode may not be able to sufficiently secure the sealing property against the plating solution. .

In order to solve this problem, it is conceivable to increase the content of glass frit in the conductive paste. In this case, however, the glass component contains the outer surface of the external electrode and the external electrode and the ceramic laminate. May be excessively precipitated at the interface of the electrode, thereby hindering the electrical conduction between the external electrode and the external conductive element to be connected thereto,
In some cases, conduction between the external electrode and the extraction electrode, and eventually conduction between the external electrode and the internal electrode via the extraction electrode, may be hindered.

[0007] The sealing property required for the ceramic laminate is not limited to the plating solution as described above. For example, even when the multilayer ceramic electronic component is used under high humidity, if the sealing performance of the ceramic laminate is poor, the IR, the humidity resistance, and the like may be deteriorated. Therefore, an object of the present invention is to provide a multilayer ceramic electronic component and a method of manufacturing the same that can solve the above-described problems.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a plurality of stacked ceramic layers, and an internal electrode formed along the interface between the specific ceramic layers and connected to the internal electrode and provided at an end of the interface. A ceramic multilayer body including an extraction electrode extending to the outside and an external electrode formed on an outer surface of the ceramic laminate so as to be electrically connected to the extraction electrode. In order to solve the above-mentioned technical problem, the extraction electrode is made of a conductive paste containing a resin.

The present invention has been made under the following viewpoints. That is, in making the present invention,
As a result of investigating the manner in which the above-mentioned plating solution and external moisture penetrate into the inside of the ceramic laminate, the internal electrode and the extraction electrode and the ceramic layer in contact with them are not densely sintered with each other. Has a tendency to form along the interface between the ceramic layers where the internal and extraction electrodes are located. Therefore, if this interface is properly sealed to the outside, it will effectively act to improve the plating solution resistance and moisture resistance of the ceramic laminate. An extraction electrode is formed from the conductive paste to be applied, thereby imparting conductivity to the extraction electrode and attaining a sealing effect.

As the resin contained in the above-mentioned conductive paste, it is preferable to use a resin having heat resistance that can withstand the temperature at the time of baking of the external electrode performed later. For example, a polyimide resin can be advantageously used. When a polyimide resin is used as the resin contained in the conductive paste, preferably, the conductive paste contains 10 to 30% by weight of a polyimide resin and 70% by weight of a metal powder.
９０90 wt%.

[0011] The present invention is also directed to a method for manufacturing a multilayer ceramic electronic component as described above. The manufacturing method according to the present invention includes the following steps. That is, a plurality of stacked ceramic layers, and an internal electrode formed along the interface between the specific ceramic layers, including an internal electrode and a drawing member that extends to the end of the interface and extends to the end of the interface. A raw ceramic laminate of a burnable material is provided. Next, the green ceramic laminate is fired. At this time, the above-mentioned burnable material is burned off, thereby forming a cavity in the portion where the drawer member was formed. Next, the cavity is filled with a conductive paste containing a resin, thereby forming an extraction electrode in contact with the internal electrode. Next, an external electrode is formed on the outer surface of the ceramic laminate so as to be electrically connected to the extraction electrode.

As the above-mentioned burnable material, any material can be used as long as it can be burned off in the firing step of the green ceramic laminate. For example, carbon, resin and the like are advantageously used.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is directed to a plurality of stacked ceramic layers, and an internal electrode formed along the interface between the specific ceramic layers and extending to the end of the interface. A multilayer ceramic electronic component including an extraction electrode, a ceramic laminate, and an external electrode formed on an outer surface of the ceramic laminate so as to be electrically connected to the extraction electrode. Instead, the present invention can be equally applied to other multilayer ceramic electronic components such as a multilayer ceramic varistor, a multilayer ceramic filter, and a ceramic multilayer circuit board.

An embodiment of the present invention will be described below with reference to a multilayer ceramic capacitor. In FIG.
1 shows a cross section of a multilayer ceramic capacitor 1 as a multilayer ceramic electronic component according to an embodiment of the present invention. As is well known, the multilayer ceramic capacitor 1 includes a rectangular parallelepiped ceramic laminate 3 including a plurality of laminated ceramic layers 2. A plurality of internal electrodes 4 and 5 are formed inside the ceramic laminate 3 so as to extend along a plurality of interfaces between the specific ceramic layers 2. In addition, an extraction electrode 6 connected to each of the internal electrodes 4 and 5 and extending to the end of this interface so as to be along the interface between the ceramic layers 2 on which the internal electrodes 4 and 5 are formed.
And 7 are formed.

The internal electrodes 4 and 5 and the extraction electrodes 6 and 7 are each classified into two groups. That is, the extraction electrodes 6 and 7 are extracted to the outer surface of the ceramic multilayer body 3, more specifically, to one of the first and second end surfaces 8 and 9 of the ceramic multilayer body 3 facing each other. There is a first group of extraction electrodes 6 extending to the first end face 8 and a second group of extraction electrodes 7 extending to the second end face 9. There is a first group of internal electrodes 4 connected to one group of extraction electrodes 6 and a second group of internal electrodes 5 connected to a second group of extraction electrodes 7. These first group of internal electrodes 4 and extraction electrodes 6 are provided.
The internal electrodes 5 and the extraction electrodes 7 of the second group are alternately arranged in the stacking direction.

The first and second end faces 8 and 9 of the ceramic laminate 3 are respectively connected to the first and second external electrodes 6 and 7 so as to be electrically connected to the extraction electrodes 6 and 7, respectively. Electrodes 10 and 11 are formed. External electrodes 10 and 11 are formed, for example, by applying paste containing glass frit and metal powder on end faces 8 and 9, and baking the paste.

Plating films 12 and 13 are formed on external electrodes 10 and 11 by, for example, electroplating. These plating films 12 and 13
Improvement of the solderability of the external electrodes 10 and 11 or Ag when the external electrodes 10 and 11 contain Ag
Is formed for the purpose of suppressing solder erosion, etc., for example, a film made of solder or tin or a film made of Ni or Cu and a film made of solder or tin or the like Or a multilayer film.

In such a multilayer ceramic capacitor 1, this embodiment is characterized in that the extraction electrodes 6 and 7 are made of a conductive paste containing a resin. As this conductive paste, for example, a commercially available conductive adhesive or the like can be used. The conductive paste functions to impart conductivity to the extraction electrodes 6 and 7 and to provide a sealing effect.
Therefore, the internal electrodes 4 or 5 serve as paths through which the plating solution for forming the above-described plating films 12 and 13 and external moisture penetrate into the inside of the ceramic laminate 3 through the relatively porous external electrodes 10 and 11. And the interface between the ceramic layers 2 where the extraction electrodes 6 or 7 are located,
With the extraction electrode 6 or 7 made of conductive paste,
It can be advantageously sealed to the outside.

Next, one embodiment of a method of manufacturing the above-described multilayer ceramic capacitor 1 will be described with reference to FIGS. First, as shown in FIG. 2, a ceramic green sheet 14 to be the ceramic layer 2 is prepared. Although the ceramic green sheet 14 shown in FIG. 2 has only dimensions for obtaining one multilayer ceramic capacitor 1 for convenience of explanation, a plurality of multilayer ceramic capacitors 1 are simultaneously obtained in factory-scale production. In order to do so, a ceramic green sheet of a larger size in a mother state is prepared on the assumption that it will be cut later.

Next, as shown in FIG. 2, for example, a first group of internal electrodes 4 is formed on the ceramic green sheet 14. The internal electrode 4 is formed so as not to reach the end of the ceramic green sheet 14. Next, as shown in FIG. 3, a drawing member 15 is further formed on the ceramic green sheet 14 so as to contact the internal electrode 4. The extraction member 15 is formed at a portion where the extraction electrode 6 is to be formed, and is formed to extend to one end of the ceramic green sheet 14.

The draw-out member 15 is made of a material that can be burned out during firing of the green ceramic laminate 3 described later, and is made of, for example, a carbon paste obtained by kneading carbon powder with an organic binder, or a resin. As can be inferred from the configuration shown in FIG. 5 described later, the extraction member 15 is formed such that a predetermined dimension at its end overlaps the end of the internal electrode 4, but only at the end face of the internal electrode 4. 4 may be formed so as to be in contact with the end face.

After the above operation is performed on the plurality of ceramic green sheets 14 and the same operation related to the second group of internal electrodes 5 is performed, the plurality of ceramic green sheets 14 Stacked in order, thereby providing a green ceramic laminate 3 as shown in FIG. As shown in FIG. 4, the ceramic laminate 3 includes a plurality of ceramic layers 2 formed by laminated ceramic green sheets 14 and is formed along an interface between specific ceramic layers 2. Internal electrode 4 and extraction member 15 contacting it and internal electrode 5 and extraction member 1 contacting it
6 is provided.

When a green ceramic laminate 3 is obtained, after stacking a plurality of ceramic green sheets,
Pressing is performed. At this time, in the step shown in FIG. 3, it is preferable that the extraction members 15 and 16 are formed to have a thickness which is about twice the thickness of each of the internal electrodes 4 and 5. Because of this, as shown in FIG. 4, the difference in thickness between the region where both the internal electrodes 4 and 5 are located and the region where the internal electrodes 4 and 5 are not located is reduced.
6 is advantageously absorbed by the thickness of the ceramic laminate 3
This is because a substantially even press is exerted on the whole.

Next, the green ceramic laminate 3 is fired. At this time, the burnable material, such as carbon, constituting the extraction members 15 and 16 is burned off, and as a result, as shown in FIG. Was formed in the part where
Is formed. Next, as shown in FIG.
Is filled with a conductive paste containing a resin, thereby forming the extraction electrode 6 that contacts the internal electrode 4.
Although not shown in FIG. 6, the extraction electrode 7 that contacts the internal electrode 5 is formed in the same manner. Such a filling operation of the conductive paste is achieved by applying a conductive paste to the end faces 8 and 9 of the ceramic laminate 3 or immersing the ceramic laminate 3 in the conductive paste and bringing it under reduced pressure. You.

Next, as shown in FIG. 1, after removing unnecessary conductive paste adhered to the outer surface of the ceramic laminate 3, the ceramic laminate 3 is electrically connected to the extraction electrodes 6 and 7, respectively. External electrodes 10 and 11 are formed on end surfaces 8 and 9 of laminate 3 by baking, respectively, and plating films 12 and 13 are formed on external electrodes 10 and 11 by electroplating, respectively.

Thus, a desired multilayer ceramic capacitor 1 is completed. As the resin contained in the above-mentioned conductive paste, an external electrode 1 formed thereafter is used.
It is preferable to use a material having heat resistance that can withstand the baking temperatures of 0 and 11. For example, a polyimide resin can be advantageously used because it can withstand a temperature of about 500 ° C.

When a polyimide resin is used as the resin contained in the conductive paste, as will be understood from the experimental examples described later, the conductive paste contains 10 to 30 wt% of the polyimide resin and 70 to 90 wt% of the metal powder, respectively. It is preferable to use The external electrodes 10 and 11
May be formed by a method other than baking, such as a dry plating method such as sputtering, vapor deposition, or ion plating, or an electroless plating method. When the external electrodes 10 and 11 are formed by a method other than baking, the ceramic laminate 3 including the extraction electrodes 6 and 7 may not be exposed to such a high temperature. In this case, the ceramic laminate 3 is contained in the conductive paste. The resin does not need to have special heat resistance.

The conductive paste may be solidified at the stage when the multilayer ceramic capacitor 1 is completed and the extraction electrodes 6 and 7 are formed, or the paste-like property may be maintained. . Further, the conductive paste may contain a glass component. Further, the plating films 12 and 13 may be formed by dry plating instead of wet plating such as electroplating.

An experimental example carried out according to the present invention will be described below with reference to FIGS.

[0030]

EXPERIMENTAL EXAMPLE 1 Internal electrodes 4 and 5 each containing a metal component of Ag / Pd were formed on a plurality of dielectric ceramic green sheets 14 containing BaTiO ₃ as a main component. The drawing members 15 and 16 were formed so as to be in contact with each other. next,
These green sheets 14 were stacked, pressed, and then cut to obtain a plurality of chip-shaped raw ceramic laminates 3, and then fired at 1250 ° C. At this time, the cavity 17 was formed in the portion where the extraction members 15 and 16 were formed.

Next, a conductive paste containing Ag / Pd metal powder and a polyimide resin is applied to the end surfaces 8 and 9 of the ceramic laminate 3 and the pressure is reduced so that the conductive paste is hollow. 17 and thereby, extraction electrodes 6 and 7 were formed. In addition, as this conductive paste, as shown in the following Table 1, the amount of the metal powder contained therein was changed in the range of 60 to 95% by weight, and a sample was prepared for each. did. As shown in Table 1, the end faces 8 of the ceramic laminate 3 of the extraction electrodes 6 and 7 were also set for each sample.
And the formation distance from each of 9 was also varied in the range of 110-280 μm.

Next, unnecessary conductive paste adhered to the outer surface of the ceramic laminate 3 is removed by applying barrel polishing, and then the paste containing Ag and glass frit is removed from the end face of the ceramic laminate 3. 8 and 9
The external electrodes 10 and 11 were formed by coating on the substrate and baking at 450 ° C. Next, electroplating of Ni and Sn was sequentially performed on the external electrodes 10 and 11 to form plating films 12 and 13.

For each sample of the multilayer ceramic capacitor 1 thus obtained, the equivalent series resistance (ESR),
The rate of occurrence of structural defects such as peeling and the number of defective moisture-resistant loads were evaluated. The results are shown in Table 1. The parameter for calculating the structural defect occurrence rate is 100K, and the humidity resistance load test is performed under the conditions of a temperature of 85 ° C., a relative humidity of 85%, and an applied voltage of 50 V (= 2 WV). , The number of defective occurrences after 1000 hours have passed.

[0034]

[Table 1]

As can be seen from Table 1, for all the samples, each of the extraction electrodes 6 and 7 is inward from each of the end faces 8 and 9 of the ceramic laminate 3 by 300.
It is formed at a distance of less than μm. Among them, Samples 2 to 4 in which the metal content in the conductive paste is 70 to 90 wt% show favorable results in all of the ESR, the structural defect occurrence rate, and the number of moisture resistance load defects.

On the other hand, in the case of Sample 1 in which the metal content in the conductive paste was 60% by weight, since the content of the resin was increased, there was no problem with respect to the structural defect occurrence rate and the number of defective moisture resistant loads. It can be seen that the sealing performance is good, but it is not preferable because the ESR value increases. On the other hand,
In the case of Sample 5 in which the metal content in the conductive paste exceeds 90 wt%, the ESR value can be lowered, but there are problems with the structural defect occurrence rate and the number of defective moisture-resistant loads. Can not expect much.

The metal powders contained in the internal electrodes 4 and 5, the extraction electrodes 6 and 7, and the external electrodes 10 and 11 may be other than those used in the above-described experimental examples. It has been confirmed that similar results can be obtained.

[0038]

EXPERIMENTAL EXAMPLE 2 A multilayer ceramic capacitor 1 was manufactured in the same manner as in Experimental Example 1 except for the following points. That is, in this experimental example 2, the conductive paste was all 80 wt%.
As shown in Table 2 below, while using a metal powder having a metal powder content of
Samples varied in the range of 0 to 330 μm were prepared.

[0039]

[Table 2]

As is clear from Table 2, even when a conductive paste having a metal powder content of 80 wt% is used, the sample 9 in which the formation distances of the extraction electrodes 6 and 7 are 330 μm is obtained. As in the case of the sample 1 in the experimental example 1, there is no problem regarding the structural defect occurrence rate and the number of defective moisture-resistant loads, and the sealing property is good.
It is not preferable because the value increases.

On the other hand, when the formation distances of the extraction electrodes 6 and 7 are set to 300 μm or less as in Samples 6 to 8, good results are obtained in all of the ESR, the structural defect occurrence rate, and the number of defective moisture-resistant loads. The results are shown.

[0042]

As described above, according to the multilayer ceramic electronic component of the present invention, the extraction electrode formed by reaching the end to the outer surface of the ceramic laminate so as to be connected to the external electrode is made of resin. Since the conductive paste is included, the conductive paste not only gives conductivity to the extraction electrode but also exhibits a sealing effect. Therefore, the interface between the ceramic layer where the internal electrode and the extraction electrode are located, which is a path through which the plating solution or external moisture enters the inside of the ceramic laminate, is advantageously sealed by the conductive paste constituting the extraction electrode. Therefore, the sealing performance of the ceramic laminate can be improved, and as a result, a highly reliable laminated ceramic electronic component can be obtained.

In the present invention, a polyimide resin is used as a resin contained in the conductive paste, and a polyimide resin is used in the conductive paste.
When the content of the metal powder is 30 to 90 wt% and the metal powder content is 70 to 90 wt%, not only can the extraction electrode be provided with heat resistance enough to withstand the temperature at which the external electrode is baked thereafter, A multilayer ceramic electronic component having better sealing properties and electrical characteristics of the ceramic laminate can be obtained.

Further, according to the method for manufacturing a multilayer ceramic electronic component of the present invention, in order to form an extraction electrode, a burnable extraction member is previously added to a raw ceramic laminate at a portion where the extraction electrode is to be formed. Forming and firing the ceramic laminate, by burning out the drawer member, forming a cavity in the portion where the drawer member was formed,
Since the step of filling the cavity with the conductive paste is employed, the extraction electrode can be easily and efficiently formed at a desired portion.

[Brief description of the drawings]

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

FIG. 2 is a perspective view showing a ceramic green sheet 14 on which an internal electrode 4 is formed, which is prepared for obtaining the multilayer ceramic capacitor 1 shown in FIG.

FIG. 3 is a perspective view showing a state in which a drawing member 15 is further formed on the ceramic green sheet 14 shown in FIG.

4 is a cross-sectional view showing a green ceramic laminate 3 obtained by stacking the ceramic green sheets 14 shown in FIG.

5 is an enlarged cross-sectional view showing a part of the fired ceramic laminate 3 in which a cavity 17 is formed by firing the raw ceramic laminate 3 shown in FIG.

6 is a diagram corresponding to FIG. 5, in which the extraction electrode 6 is formed by filling a cavity 17 shown in FIG. 5 with a conductive paste.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Multilayer ceramic capacitor (multilayer ceramic electronic component) 2 Ceramic layer 3 Ceramic laminated body 4,5 Internal electrode 6,7 Leader electrode 8,9 End face (outer surface) 10,11 External electrode 15,16 Leader member 17 Cavity

Claims (3)

[Claims] A plurality of stacked ceramic layers; and an internal electrode formed along an interface between the specific ceramic layers and an extraction electrode connected to the internal electrode and extending to an end of the interface. A ceramic laminate, and an external electrode formed on an outer surface of the ceramic laminate so as to be electrically connected to the extraction electrode, wherein the extraction electrode contains a resin. A multilayer ceramic electronic component, comprising: a conductive paste comprising: 2. The multilayer ceramic electronic component according to claim 1, wherein the conductive paste contains 10 to 30% by weight of a polyimide resin and 70 to 90% by weight of a metal powder. 3. A plurality of laminated ceramic layers, and a drawing member formed along an interface between the specific ceramic layers and extending to an end of the interface in contact with the internal electrode and to the end of the interface. Preparing a raw ceramic laminate, wherein the draw-out member is made of a burnable material, firing the green ceramic laminate and burning out the burnable material, thereby forming the draw-out member Forming a cavity in the portion that has been formed, filling the cavity with a conductive paste containing a resin, thereby forming an extraction electrode that contacts the internal electrode, and electrically connected to the extraction electrode. A method for manufacturing a multilayer ceramic electronic component, comprising: forming an external electrode on an outer surface of the ceramic laminate.