JPH0845770A - Manufacture of multilayer electronic component - Google Patents

Abstract

PURPOSE:To prevent aggregation of metal of inner electrodes at the time of baking, and prevent deterioration of characteristics. CONSTITUTION:A multilayer electronic component is manufactured by the following: a process for forming a laminate 23 wherein unbaked ceramic layers 21, 27 and inner electrode layers 25, 26 of conductive paste are alternately laminated and bonded with pressure, a process for baking the laminate 23, a process for coating the end portion of the laminate 23 wherein the inner electrodes 25, 26 are exposed with conductive paste, and a process wherein outer electrodes 2, 2 are formed by baking the conductive paste on the end portion of the laminate. In this case, paste 24 for pushing use whose shrinkage factor at the time of baking is equal to or larger than that of the laminate 23 is spread on the surface of an overlapping part of the inner electrodes 25, 26 via the ceramic layer 21 of the unbaked laminate 23. The laminate 23 and the paste 24 are baked at the same time.

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 laminated electronic component such as a laminated ceramic capacitor or a laminated ceramic inductor, and more particularly to a laminated electronic component in which deterioration of characteristics due to condensation of a conductor material in an internal electrode does not easily occur and a method for manufacturing the same. Regarding

[0002]

2. Description of the Related Art Monolithic ceramic capacitors and monolithic ceramic inductors are typical examples of laminated electronic components, and many composite elements such as LC components have been developed by combining them. A multilayer ceramic capacitor, which is a typical example of a multilayer electronic component, has a large number of layered internal electrodes stacked with ceramic layers interposed therebetween, and the internal electrodes are alternately drawn out to the end faces of the ceramic layer laminate. Then, external electrodes are formed on the end faces of the stacked body from which these internal electrodes are drawn out.

A general method for manufacturing such a monolithic ceramic capacitor is, for example, by forming a ceramic slurry in which a dielectric ceramic powder is dispersed in an organic binder into a sheet shape to form a ceramic green sheet, and by a screen printing method or the like. The internal electrode pattern is printed on this ceramic green sheet with a conductive paste. Then, the ceramic green sheets on which the internal electrode patterns are printed are stacked, and further, a plurality of ceramic green sheets on which the internal electrode patterns are not printed are stacked on both sides thereof. The laminate thus obtained is cut into chips so that the internal electrodes are exposed at the end faces, and the chips are fired. Then, by polishing the sintered laminated body,
An internal electrode is exposed on the end face, a conductive paste is applied to this end, and this is baked to form an external electrode, thereby completing the multilayer chip capacitor.

As another method for manufacturing a monolithic ceramic capacitor, before firing a ceramic laminated body, a conductive paste is applied to the end portion thereof in advance, and then the ceramic laminated body is fired and the conductive paste is baked at the same time. There is also a manufacturing method. Further, as a method for obtaining a laminated body, a so-called printing method in which a ceramic paste and a conductive paste are alternately printed is adopted in addition to a so-called sheet method in which a ceramic green sheet is used.

The multilayer electronic component represented by such a multilayer ceramic capacitor is required to have a large capacity and a high inductance as well as a small size. In order to meet this demand, in the recent laminated electronic components, the ceramic layer is made as thin as possible, and more layers can be laminated within a limited thickness. However, as the number of stacked layers increases, the difference in the stacked thickness between the portion where the internal electrodes overlap with each other via the ceramic layer inside the stacked body and the margin portion other than that increases due to the thickness of the internal electrodes. In addition, internal stress and strain increase due to differences in the thermal contraction rate and thermal expansion coefficient between the metal contained in the internal electrode and the ceramic of the ceramic layer during firing. Therefore, in order to solve such a problem, it is necessary to make the thickness of the internal electrode as thin as possible.

[0006]

However, when the internal electrodes are made thin, the internal electrodes after firing are discontinuous in an island shape, resulting in deterioration of characteristics such as a decrease in capacitance and an increase in electrical resistance. . This is because when the internal electrode is thin, the metal forming the internal electrode aggregates and partially hardens, while the metal structure becomes rough or lacks, so the effective area of the internal electrode decreases. Resistance or increase in resistance due to disconnection of the conductor. The present invention solves the above-mentioned conventional problems, and provides a method for manufacturing a laminated electronic component capable of preventing the aggregation of the metal of the internal electrode during firing.

[0007]

According to the present invention, in order to achieve the above-mentioned object, a pressing paste is applied to the surface of a portion of an unfired laminate where internal electrodes are overlapped, and the laminate is fired. By simultaneously firing the pressing paste at the same time, the shrinkage of the paste during firing was used to tighten the laminate, thereby preventing metal aggregation in the internal electrodes.

That is, in the method for manufacturing a laminated electronic component according to the present invention, a step of alternately laminating unfired ceramic layers and internal electrodes made of a conductive paste and press-bonding to obtain a laminated body, and firing the laminated body. In order to manufacture a laminated electronic component, a step, a step of applying a conductor paste to the end portion of the laminated body where the internal electrodes are exposed, and a step of baking the conductive paste on the end portion of the laminated body to form an external electrode, In this case, a pressing paste of a material having a shrinkage factor at the time of firing equal to or higher than that of the laminated body is applied to the surface of the portion where the internal electrodes overlap with each other through the ceramic layer of the unfired laminated body, and then the laminated body. And the pressing paste are simultaneously fired.

When a conductive paste is used as the pressing paste, the pressing paste after firing is covered with an insulating film. The pressing paste is preferably applied so as to surround the laminated body. Further, a conductive paste is used as the pressing paste, the conductive paste is applied so as to cover the entire laminated body, and after firing, at least the internal electrodes of the conductor film formed except for the end portion of the laminated body exposed. It is also possible to remove the intermediate portion and separate the both end portions as external electrodes.

Further, a pressing paste is applied so as to cover the entire laminated body and baked, and then the formed film is removed.
After that, an external electrode may be formed by applying a conductive paste to the end of the laminate and baking it. In this case, when using the insulating paste as the pressing paste, after firing,
At least the film formed from the end of the stacked body where the internal electrode is exposed may be removed. On the other hand, when a conductive paste is used as the pressing paste, it is necessary to remove the formed conductor film after firing so that the external electrodes are not short-circuited.

[0011]

When the present inventors manufacture a monolithic ceramic electronic component such as a monolithic ceramic capacitor, they are fired without applying the conductive paste for forming the external electrodes to the ends of the non-fired laminate. Then, it was found that the conductive paste for forming the external electrode was applied to the end portion of the unfired laminated body in advance, and this was co-fired, and that the latter had less metal aggregation in the internal electrode. . This is because when a conductive paste is applied to the outer surface of an unfired laminate and this is co-fired with the laminate, when the applied conductive paste is fired, the laminate is tightened and swelling of the laminate is suppressed. Therefore, it is considered that the metal of the internal electrode is prevented from aggregating and the metal of the internal electrode is prevented from aggregating.

Therefore, in the method for manufacturing a laminated electronic component according to the present invention, the shrinkage factor during firing is equal to or higher than that of the laminated body on the surface of the portion where the internal electrodes overlap with each other through the ceramic layer of the unfired laminated body. Apply the pressing paste of the material of
Thereafter, the laminate and the paste are co-fired to suppress the bulging of the laminate at the time of firing, thereby preventing the metal from agglomerating in the internal electrodes and forming a uniform conductor layer.

An example of the pressing paste is a conductive paste used to form an external electrode. The conductor film is an insulating film so that the conductor film formed by firing does not short circuit. cover. When a conductive paste is used as the pressing paste, the conductive paste is applied so as to cover the entire laminated body, and after firing, a conductor formed except at least the end portion of the laminated body where the internal electrodes are exposed. The outer electrode can be formed at the same time by removing the intermediate portion of the film and separating both end portions thereof as the outer electrodes.

As the pressing paste, in addition to the conductive paste, an insulating paste such as a ceramic paste, which has a higher shrinkage rate at the time of firing than the ceramic forming the laminate, can be used. In this case, the pressing paste is applied so as to cover the entire laminated body, and after firing, the formed film is removed from at least the end portion of the laminated body where the internal electrode is exposed, and the external electrode is attached to the removed trace. You may form. When the pressing paste is provided around the laminated body so as to surround the portion where the internal electrodes overlap with each other through the ceramic layer, the bulging of the laminated body during firing can be surely suppressed. In that respect, the effect is further enhanced when the pressing paste is applied to the entire surface of the laminate.

[0015]

[Embodiments] Next, embodiments of the present invention will be specifically described by taking a case of manufacturing a monolithic ceramic capacitor as an example. For example, as shown in FIG. 5, a ceramic slurry in which a dielectric ceramic powder is dispersed in an organic binder is molded into a sheet shape to form a ceramic green sheet 11 or 1.
1 are formed, and the internal electrode patterns 15 and 16 are printed on the ceramic green sheets 11, 11 ... With a conductive paste by a screen printing method or the like. Then, the ceramic green sheets 11, 11 ... With the internal electrode patterns 15, 16 printed are laminated as shown in FIG.
Further, a plurality of ceramic green sheets 17, 17 on which internal electrode patterns are not printed are stacked on both sides thereof.

The laminate thus obtained is cut into chips so that the internal electrode patterns are exposed at the end faces, and
An unsintered laminate 23 as shown in (a) is obtained. In FIG. 1A, reference numerals 21 and 27 denote ceramic layers formed by the ceramic green sheets 11 and 17, and 25 and 26 denote the internal electrode patterns 1.
5 shows the internal electrodes formed by 5 and 16.

Next, the external electrodes 2, 2 are attached to the end portions of the laminated body 23.
Conductive pastes 22 and 22 for forming are applied.
Further, a pressing paste 24 is applied to an intermediate portion of the laminated body 23 so as to surround the laminated body 23. The pressing paste 24 is used for the ceramic layer 2 which constitutes the laminated body 23.
It is a paste having a larger shrinkage rate during firing than 1, 27, and, for example, the same paste as the conductive pastes 22, 22 can be used. The external electrodes 2, 2 as the pressing paste 24
If the same conductive pastes 22 and 22 for forming are used, the pressing paste 24 and the conductive paste 22,
22 can be applied simultaneously.

Next, the laminated body 23 is fired together with the conductive pastes 22 and 22 and the pressing paste 24. At this time, contraction of the pressing paste 24 suppresses expansion of the laminate 23 in the lamination direction, and pressure in the lamination direction is applied to the internal electrodes 25 and 26 between the ceramic layers 21 and 27. Agglomeration of metal in the internal electrodes 25, 26 is prevented.

Finally, a resin or the like is applied so as to cover the conductor film 4 formed by firing the pressing paste 24,
By providing the insulating film 8 by baking, a multilayer chip capacitor as shown in FIG. 1B is completed. In the figure, 3 is a fired laminate, 5 and 6 are fired internal electrodes, and 2 and 2 are fired external electrodes.

As the pressing paste 24, in addition to the above-mentioned conductive paste, an insulating paste such as a ceramic paste having a shrinkage rate equal to or higher than that of the ceramic constituting the laminated body when firing is used. It can also be used. In this case, since the insulating film is formed by firing, it is not necessary to further provide the insulating film thereon.

Next, the embodiment shown in FIG. 2 will be described. In this embodiment, as shown in FIG. 2A, the ceramic green sheets 11 and 17 on which the internal electrode patterns 15 and 16 are partially printed are laminated. Then, the pressing paste 24, 2 is applied only to the side surface of the central portion of the unfired laminated body 23 formed by cutting.
4 is applied, and this is co-fired with the laminated body 23. When a conductive paste is used as the pressing paste 24, the conductive film 4 formed by firing is replaced with the insulating film 8.
Covering with is the same as in the previous embodiment. Even if the pressing paste is applied to only the side surface of the unfired laminated body 23 along the laminating direction and co-firing, the same effect can be obtained.

Next, the embodiment shown in FIG. 3 will be described. In this embodiment, a conductive paste for forming the external electrodes 2 and 2 is used as the pressing paste 24, and FIG.
As shown in (a), some internal electrode patterns 15, 16
The ceramic green sheets 11 and 17 printed with are laminated and cut, and the pressing paste 24 is applied to the entire surface of the unfired laminated body 23, which is co-fired with the laminated body 23. After that, as shown in FIG. 3B, the intermediate portion of the conductor film formed by firing the pressing paste 24 is removed by polishing, chemical etching, or the like, and the conductor film is removed by the external electrode 2.
Separated as 2 at both ends. As a result, a monolithic ceramic capacitor as shown in FIG. 3B is completed.

In this embodiment, since the pressing paste 24 is applied to the entire surface of the laminated body 23, the applying process is easily performed, but a conductor film removing process is finally required. Moreover, since the pressing paste 24 is applied to the entire surface of the laminate 23, the effect of preventing the laminate from bulging during firing is high.

Next, the embodiment shown in FIG. 4 will be described. In this embodiment, either a conductive paste or an insulating paste may be used as the pressing paste 24.
As shown in (a), the pressing paste 24 is applied to the entire surface of the unfired laminate 23, and this is simultaneously fired with the laminate 23. Thereafter, as shown in FIG. 4C, the film formed by firing the pressing paste 24 is entirely removed by polishing, chemical etching, or the like, and then the external electrode 2 is formed at the end where the internal electrodes 5 and 6 are exposed. 2 is formed. In particular, in the illustrated example, first, a conductive paste is applied to the end surface of the fired laminated body 3 and baked to form the base conductor films 9 and 9 as shown in FIG. A conductive paste is applied to the end portion of the laminated body 3 including the conductor films 9 and 9 and baked to form the external electrodes 2 and 2. As a result, FIG.
A monolithic ceramic capacitor as shown in (c) is completed.

In this embodiment, since the pressing paste 24 is applied to the entire surface of the laminated body 23, the applying step is easily performed, and the subsequent film removal is also performed on the entire surface of the laminated body 3. Therefore, the removing step is performed. Is also easily done. However, a step of finally forming the external electrodes 2 and 2 is required. When an insulating paste is used as the pressing paste 24, the film formed by firing is removed only at both ends of the laminate 3, and a conductive paste is applied to both ends of the film to bake the external electrodes 2 and 2. You may form.

Although the above-described embodiments were all methods for manufacturing a monolithic ceramic capacitor, the present invention is applicable to monolithic ceramic inductors, monolithic ceramic LC parts, etc.
It is obvious that the same applies to other laminated electronic components manufactured by firing an unfired laminate having internal electrodes.

Next, a specific example of the present invention will be described. Example 1 Polyvinyl butyral, a dispersant, a plasticizer, and a 1: 1 mixed solvent of toluene and ethanol were added to a dielectric ceramic material powder containing BaTiO ₃ as a main component,
These were mixed with a ball mill to obtain a slurry. The obtained slurry was applied on a base film made of a polyethylene terephthalate film (PET film) by a roll coater to prepare a ceramic green sheet having a thickness of about 10 μm.

This ceramic green sheet is cut into a predetermined size, and a conductive paste containing Ni powder as a conductor component is applied on the cut ceramic green sheet by screen printing to form an internal electrode pattern having a thickness of about 2 μm. did. A plurality of sheets obtained by printing the internal electrode pattern are stacked, further ceramic green sheets having no internal electrode pattern printed are laminated on both sides of the sheet, and the laminated body is heated, pressed and pressure-bonded to obtain a laminated body. Was cut into a predetermined size into chips.

A conductive paste containing Ni powder was applied to both ends of the ceramic laminate, and the conductive paste was applied in a strip shape around the intermediate portion between the ends and dried. After that, the laminated body coated with this conductive paste is
_It was fired at a temperature of 1180 ° C. in an N ₂ gas atmosphere containing 2% of 2. After that, a resin paste is applied so as to cover the conductor film of the intermediate portion formed by the conductive paste,
This was baked to form an insulating film. In addition, the external electrode formed by the conductive paste applied to the end portion of the laminated body has N
The i-plating and the solder-plating were each formed to have a thickness of 2 to 3 μm. As a result, a monolithic ceramic capacitor as shown in FIG. 1 (b) was obtained. The average value of the capacitance of 100 capacitors of this laminated ceramic capacitor was 1.04 μF.

(Example 2) Instead of applying the conductive paste in a strip shape to the intermediate portion of the laminated body in Example 1, a dielectric ceramic paste for forming a ceramic layer of the laminated body is used in the same manner. A multilayer ceramic capacitor was manufactured in the same manner as in Example 1 except that the insulating film was not formed at the end. The average value of the electrostatic capacitance of 100 laminated ceramic capacitors was 1.03 μF.

(Embodiment 3) In the same manner as in Embodiment 1, instead of applying the conductive paste in a strip shape to the intermediate portion of the laminated body, a dielectric ceramic paste for forming a ceramic layer of the laminated body is similarly fired. A multilayer ceramic capacitor was manufactured in the same manner as in Example 1 except that the ceramic paste having a high shrinkage ratio was used and no insulating film was finally formed. This multilayer ceramic capacitor 100
The average value of the individual capacitances was 1.05 μF.

(Embodiment 4) Instead of applying the conductive paste in a strip shape to the intermediate portion of the laminate in the above Embodiment 1, the conductive paste is applied to the entire surface of the laminate and baked, and then the laminate Except for the external electrode portions on both ends of the conductor film, the conductor film in the middle portion is removed by etching.
A multilayer ceramic capacitor was manufactured in the same manner as in. The average value of the electrostatic capacitance of 100 laminated ceramic capacitors was 1.05 μF.

(Comparative Example) In Example 1, the laminated body was baked as it was without applying the conductive paste, and then the conductive paste was applied to the end portion of the laminated body after baking and baked to form the external electrodes. A monolithic ceramic capacitor was manufactured in the same manner as in Example 1 except for the above. The average value of the electrostatic capacitance of 100 of these laminated ceramic capacitors is 0.9.
It was 2 μF.

[0034]

As described above, in the laminated electronic component of the present invention, it is possible to suppress the bulging of the laminated body during firing, thereby preventing the metal from aggregating in the internal electrodes and forming a uniform conductor layer. Thus, it is possible to obtain a laminated electronic component having desired characteristics and stable characteristics.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view showing a method for manufacturing a monolithic ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional perspective view showing a method of manufacturing a monolithic ceramic capacitor according to another embodiment of the present invention.

FIG. 3 is a partial cross-sectional perspective view showing a method for manufacturing a monolithic ceramic capacitor according to still another embodiment of the present invention.

FIG. 4 is a partial cross-sectional perspective view showing a method for manufacturing a monolithic ceramic capacitor according to still another embodiment of the present invention.

FIG. 5 is an exploded perspective view showing an example of a stacking order of sheets when manufacturing a monolithic ceramic capacitor according to an embodiment of the present invention.

[Explanation of symbols]

 2 External Electrodes 3 Baked Laminated Body 4 Film Formed by Pressing Paste 5 Baked Internal Electrodes 6 Baked Internal Electrodes 8 Insulating Film 21 Ceramic Layer 22 Conductive Paste 23 Unfired Laminated Body 24 Pressing Paste 25 Unsintered internal electrode 26 Unsintered internal electrode 27 Ceramic layer

Front page continuation (72) Inventor Osamu Fujii 6-16-20 Ueno Taito-ku, Tokyo Inside Taiyo Induction Co., Ltd.

Claims (5)

[Claims] 1. A step of alternately stacking unfired ceramic layers and internal electrodes made of a conductive paste and press-bonding to obtain a laminated body, a step of firing the laminated body, and a laminated body in which an internal electrode pattern is exposed. In the method for manufacturing a laminated electronic component, which comprises a step of applying a conductor paste to an end of the laminated body and a step of baking the conductive paste on an end of a laminated body to form an external electrode, a ceramic layer of an unfired laminated body is formed. Applying a pressing paste of a material having a shrinkage rate at the same time as that of the same laminated body or more on the surface of the portion where the internal electrodes are overlapped with each other, and then simultaneously firing the laminated body and the pressing paste. A method for manufacturing a laminated electronic component, comprising: 2. The method of manufacturing a laminated electronic component according to claim 1, wherein the pressing paste is a conductive paste and is covered with an insulating film after firing. 3. The method for manufacturing a laminated electronic component according to claim 1, wherein the pressing paste is applied so as to surround the laminated body. 4. The pressing paste is the same conductive paste as used to form an external electrode, the conductive paste being applied to cover the entire laminate and baked, and then at least the inside. The method for producing a laminated electronic component according to claim 1, wherein an intermediate portion of the conductor film formed except the end portion of the laminated body where the electrode is exposed is removed and separated as an external electrode. 5. The pressing paste is applied so as to cover the entire laminated body and baked, and then the formed film is removed from at least the end portion of the laminated body where the internal electrodes are exposed. The method for manufacturing a laminated electronic component according to claim 1, wherein an external electrode is formed on the substrate.