JPH1126284A - Chip electronic component and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form outer electrodes in a constant size, regardless of the location at ends of a chip electronic component of miniature size. SOLUTION: A chip electronic component is provided with a chip element 13, in which inner electrodes 25 of conductive film are formed and outer electrodes 14 of a conductive film formed at the ends of the chip element 13 where the inner electrodes 15 are exposed. The outer electrodes 14 comprise thick conductors 22 formed at the ends of the chip element 13, where the inner electrodes 15 are exposed, and thin conductors 23 formed at least around the ends of the chip element 13. The thick conductors 22 are formed by baking a conductive paste painted at the end of the chip element 13. The thin conductors 23 are formed by plating the ends of the chip element 13.

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 chip-like electronic component such as a multilayer ceramic capacitor and a multilayer ceramic inductor, and more particularly, to an improvement in the shape of an external electrode formed of a conductor film formed at an end of a chip body. And a method of manufacturing the same.

[0002]

2. Description of the Related Art As chip-type electronic components, multilayer ceramic capacitors and multilayer ceramic inductors are typical ones, and composite devices such as LC components and the like combining these components have been developed in many cases. Multilayer ceramic capacitors, which are typical examples of chip-shaped electronic components,
A large number of layered internal electrodes are stacked via a ceramic layer, and the internal electrodes are drawn out to the end surface of the chip body of the ceramic layer. An external electrode made of a conductive film is formed on an end face of the chip body from which these internal electrodes are drawn.

[0003] A general method of manufacturing such a multilayer ceramic capacitor is, for example, to form a ceramic green sheet by forming a ceramic slurry in which dielectric ceramic powder is dispersed in an organic binder into a sheet shape, and by screen printing or the like. Then, an internal electrode pattern is printed on the ceramic green sheet with a conductive paste. Then, the ceramic green sheets on which the internal electrode patterns are printed are stacked, and a plurality of ceramic green sheets on which the internal electrode patterns are not printed are stacked on both sides thereof. The chip body thus obtained is cut into chips so that the internal electrodes are exposed at the end faces, and the chips are fired. Then, a conductive paste is applied to the end of the fired chip body, and the paste is baked to form external electrodes, thereby completing a multilayer chip capacitor.

As another method of manufacturing a multilayer ceramic capacitor, a conductive paste is applied in advance to an end portion of a ceramic chip body before firing, and then the ceramic chip body is fired, There is also a manufacturing method of baking. Further, as a method for obtaining a chip body, a so-called slurry method, in which ceramic paste and conductive paste are alternately printed, in addition to a so-called sheet method using ceramic green sheets, has been adopted. Chip-type electronic components represented by such a multilayer ceramic capacitor are required to have a smaller size, a larger capacity, a higher inductance, and the like.

The external electrodes of such a chip-shaped electronic component are formed by applying a conductive paste to the end of the chip element by so-called dip coating.
That is, the end surface of the chip body is pressed against a flat surface in which the conductive paste is spread to have a uniform thickness, whereby the conductive paste is applied from the end surface of the chip body to a peripheral surface in the vicinity thereof. Thereafter, the conductive paste is baked to form external electrodes.

[0006]

The conductive paste for forming the external electrodes as described above is a conductive paint having a viscosity of several thousand poise and a high surface tension. Therefore, when the chip body is particularly rectangular, the contact area of the conductive paste is different at the corners of the chip body as compared with the flat surface of the chip body. That is, since the contact area per unit volume of the conductive paste is larger in the corner portion of approximately 90 degrees than in the flat surface, the surface tension of the conductive paste acts strongly and the conductive paste is hardly wet. For this reason, when the end of the chip body is immersed in the conductive paste, on the flat surface of the chip body where the conductive paste is relatively wet, the conductive paste gets wet along the surface, but the conductive paste is hard to get wet The conductive paste does not wet up at the corners of the chip body. Therefore, the size of the conductive paste attached to the end of the chip body varies depending on the position of the chip body.

FIG. 7 shows such a chip-shaped electronic component. The chip body 3 is formed by laminating a ceramic layer 7 and internal electrodes 5 and 6, and the chip body 3 is provided at an end of the chip body 3. External electrodes 4 and 4 are formed by applying and baking a conductive paste, and the external electrodes 4 and 4 are connected to the internal electrodes 5 and 6. The conductive paste for forming the external electrodes 4 and 4 has a high surface tension at the corners of the chip body 3 and is hard to wet, while a flat surface has a lower surface tension than the corners. But easy to get wet. As a result, as shown in FIG. 7, the dimensions of the external electrodes 4 are reduced at the corners of the chip body 3, and the external electrodes 4 protrude in an arc shape in a flat portion therebetween.

The size of the chip-shaped electronic component has been further reduced, and the size of the end portion of the chip element 3 for forming the external electrode 4 has been extremely reduced. For this reason, it is required that variations in the side dimensions of the external electrodes 4 due to the portions of the chip body 3 be minimized. Nevertheless, in the rectangular chip body 3 as described above, the side dimensions of the external electrodes 4 due to the portions of the chip body 3 due to the unbalance of the surface tension of the conductive paste acting on the corner and the flat portion. Variations occur.

In such a chip-shaped electronic component, when the chip-shaped electronic component is mounted on a circuit board, a soldering failure to a land electrode on the circuit board or the like may occur depending on the mounting position and posture of the chip-shaped electronic component. . In order to suppress variations in the side dimensions of the external electrodes 4, there is a method of forming the external electrodes by vacuum deposition, sputtering, or the like. However, with these means, variations in the side dimensions of the external electrodes 4 are reduced,
Because of the batch process, there is a problem that productivity is low and cost is high.

The present invention has been made in view of such conventional problems,
Regardless of the end portion of the chip body, it is possible to form external electrodes of a certain size, thereby enabling a small chip-shaped electronic component to form an external electrode with small dimensional variations. An object is to provide an electronic component and a method for manufacturing the same.

[0011]

According to the present invention, in order to achieve the above-mentioned object, a thick-film conductor 22 formed by applying and baking a conductive paste is formed only on the end face of the chip body 13, and is formed on this end face. The thin-film conductor 23 is formed on the peripheral surface of the continuous chip body 13, thereby forming the external electrodes 14 and 14. Since the thin film conductor 23 can be formed by plating, vacuum evaporation, or the like, the thin film conductor 23 is not affected by surface tension, and can be formed at an end of the chip body 13 with uniform dimensions.

That is, in the chip-shaped electronic component according to the present invention, the chip element 13 having the internal electrodes 15 and 16 formed of a conductive film therein and the end of the chip element 13 where the internal electrodes 15 and 16 are exposed are provided. External electrodes 14, 14 made of a conductive film formed in portions of the external electrodes 14, 14.
Is a thin film conductor 22 formed on the end face of the chip body 13 where the internal electrodes 15 and 16 are exposed, and a thin film that is electrically connected to the thick film conductor 22 and is formed on at least the peripheral surface of the end of the chip body 13 And a conductor.

The method of manufacturing such a chip-shaped electronic component is based on a method of manufacturing the chip-shaped electronic component, in which an external electrode 1 made of a conductive film is provided at an end of a chip body 13 having internal electrodes 15 and 16 made of a conductive film.
As a process for forming 4 and 14, internal electrodes 15 and
Forming a thick-film conductor on the end face of the chip body with the exposed portion; and, after the step of forming the thick-film conductor, at least an end portion of the chip body so as to conduct with the thick-film conductor. Forming a thin film conductor 23 on the peripheral surface.

The thick film conductor 22 is formed by baking a conductive paste applied to the end face of the chip body 13. The thin film conductor 23 is formed by applying a plating film to an end of the chip body 13. When the thin film conductor 23 is formed by the plating film in this manner, when the conductor films 16 and 17 exposed on the end surface of the chip body 13 and the peripheral surface adjacent thereto are formed on the ceramic layer 21, the chip body 1
The plating film easily adheres to the peripheral surface near the end of No. 3. Since such a thin film conductor 23 is not affected by the surface tension at all, unlike the case where a conductive paste is applied, a conductive film is uniformly formed on the peripheral surface near the end face of the chip body 13, and the dimensional variation is reduced. Does not occur.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a preferred embodiment of a chip-type electronic component according to the present invention. First, a ceramic slurry is prepared by uniformly dispersing a ceramic raw material powder in an organic binder dissolved in a solvent, and then applying the ceramic slurry to a thin and uniform thickness on a base film such as a polyethylene terephthalate film, drying, and drying. Make a ceramic green sheet. Thereafter, the ceramic green sheet is cut into an appropriate size.

Next, an internal electrode pattern is printed on each of the cut ceramic green sheets. Ceramic green sheets on which the internal electrode patterns are printed are stacked, and further, ceramic green sheets on which no internal electrode patterns are printed, so-called dummy sheets, are stacked on both sides thereof, and these are pressed to obtain a chip body. This chip body is cut vertically and horizontally and divided into individual chip-shaped chip bodies. Then, these chip bodies are fired to obtain fired chip bodies.

In this chip body 13, a ceramic layer 21 made of a dielectric material having internal electrodes 15 and 16 as shown in FIG. 4 is laminated, and ceramic layers 21 and 21 having no internal electrodes formed on both sides thereof. Each is stacked. In such a chip body 13, the internal electrodes 1
Are alternately led out to a pair of opposite sides of the upper and lower ceramic layers 21. Are opposed to each other with the ceramic layer 21 interposed therebetween, thereby obtaining a capacitance as a capacitor. Also, these internal electrodes 15, 15...
And the side piece adjacent to it. Therefore, in the example shown in FIG. 4, the internal electrodes 15, 15,.
It is shaped like a letter. The internal electrodes 15, 15,... Are led out not only to the side edges of the chip body 13 but also to the side pieces adjacent thereto. And the external electrode 1
This is for increasing the adhesion strength between the chip bases 4 and 14 and the chip element 13.

The internal electrodes 15, 1 of the ceramic layer 21
The conductor film 16 is provided at the corner at the end opposite to the side from which
Are formed, and the conductor films 16, 16 are led out near the end of the ceramic layer 21 and the end of the side connected thereto. Its shape is a triangular shape separated on both sides. The conductor films 16 are provided so that the plating film can easily reach the end of the chip body 13 and the peripheral surface in the vicinity thereof. Furthermore, an internal electrode 1 constituting a counter electrode
Band-shaped conductor films 17, 17 are formed on both sides of the upper and lower dummy ceramic layers 21, 21 in which 5, 15,... Are not formed. In FIG. 4, band-shaped conductor films 17, 17 are formed on the upper side of the upper dummy ceramic layer 21, and in FIG. 4, band-shaped conductor films 17, 17 are formed on the lower side of the dummy ceramic layer 21. 17
Are formed. These conductor films 17 are also provided so that the plating film can be easily attached to the side surface near the end of the chip body 13.

A conductive paste is prepared by dispersing a conductive powder such as Ag or Ag-Pd in an organic binder dissolved in a solvent. As shown in FIGS. 1A and 2, the conductive paste is applied to both ends of the chip body 13 from which the internal electrodes 15 and 16 are led out, and this is baked at a temperature of, for example, about 800 ° C. Thick film conductors 22, 22 are formed. The thick film conductors 22, 22 are formed by immersing only the end faces of the chip body 13 in a conductive paste and baking. Of course, due to the variation of the immersion depth in the conductive paste, the conductive paste may slightly wrap around the end surface of the chip body 13 beyond the end face thereof. What is necessary is just to be in the range formed. However, basically, the thick film conductors 22, 22
Is preferably formed only on substantially the end face of the chip body 13 from the viewpoint of appearance.

Further, the end of the chip body 13 is plated. For example, a sensitizer of a Sn solution and an activator of a Pd solution are prepared, and both ends including the end surface of the chip body 13 are immersed in the sensitizer and the activator to a certain depth. Thereby, both ends of the chip body 13 are activated. Next, after the chip body 13 was washed with water, the chip body 13 was immersed in a Ni plating bath kept at 45 ° C., and electroless plating was performed on the end including the end surface of the chip body 13. As shown in FIG. 1B and FIG. 3, the thin film conductor 23 is formed.

The chip body 13 has internal electrodes 15, 15...
, 17, 17,..., The plating film easily adheres to the peripheral surface near the end of the chip body 13. Further, the adhesion strength between the external electrodes 14 and 14 and the chip body 13 increases. External electrodes 14 and 14 are formed at the ends of the chip body 13 by the thick film conductor 22 and the thin film conductor 23. Thus, a multilayer capacitor as a chip-shaped electronic component is completed. Note that the thin film conductor 23 may be formed by an electrolytic plating method instead of the electroless plating method as described above.

In such a chip-shaped electronic component, the end of the chip body 13 is not immersed in a viscous conductive paste to apply the conductive paste. Then, after baking, the end including the end surface of the chip-shaped component 13 is immersed in a very viscous plating activator, and the portion is plated. Thus, the external electrodes can be formed by forming the conductor film on the peripheral surface of the chip body 13 without being substantially affected by the viscosity of the processing agent. Therefore, as shown in FIG. 3, the external electrode 1 is formed between the corner portion and the flat portion of the chip body 13.
There is no difference between the dimensions 4 and 14.

In the example shown in FIG. 5, the internal electrodes 15, 15.
A conductor film is formed separately on both sides of a portion led out to the end side of the ceramic layer 21 of FIG. The conductor films separated on both sides are for facilitating the plating film to reach the end of the chip body 13 and the peripheral surface in the vicinity thereof.
In the example shown in FIG. 6, the conductor films 16, 16,...
The other internal electrode 15 is formed in a strip shape over the entire length of the other end facing the one end of the ceramic layer 21 from which it is led out.

According to the present invention, not only the internal electrode for the capacitor for obtaining the capacitance but also the circular electrode for obtaining the inductance value is formed on the magnetic ceramic, or the magnetic ceramic having such an inductor electrode. Layers and
A chip body may be formed by combining and laminating a dielectric ceramic layer having the above-described counter electrode or another layer. Further, the means for forming the thin film conductor 23 can be formed by vacuum deposition, sputtering, or the like in a state where the intermediate portion of the chip body 13 is masked, in addition to the plating as described above.

[0025]

As described above, in the chip-shaped electronic component according to the present invention, the size of the external electrodes 14, 14 does not vary depending on the end portion of the chip body 13,
External electrodes 14 having uniform dimensions over the entire periphery of the end of the chip body 13 can be formed. by this,
When the chip-shaped electronic component is mounted on the circuit board, the soldering of the external electrodes of the chip-shaped component does not occur.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional side view showing a state before and after a thin film conductor of an external electrode is formed in an example of a chip-shaped electronic component according to the present invention.

FIG. 2 is a partially longitudinal perspective view showing a state before a thin film conductor of an external electrode is formed in the example of the chip-shaped electronic component.

FIG. 3 is a partially longitudinal perspective view showing a state after a thin film conductor of an external electrode is formed in the example of the chip-shaped electronic component.

FIG. 4 is an exploded perspective view of each ceramic layer showing a laminated structure of a laminated body of the example of the chip-shaped electronic component.

FIG. 5 is an exploded perspective view of respective ceramic layers showing a laminated structure of a laminate of another example of a chip-shaped electronic component according to the present invention.

FIG. 6 is an exploded perspective view of respective ceramic layers showing a laminated structure of a laminated body of another example of a chip-shaped electronic component according to the present invention.

FIG. 7 is a partially longitudinal perspective view showing a conventional example of a chip-shaped electronic component.

[Explanation of symbols]

 13 Chip Element 14 External Electrode 15 Internal Electrode 16 Internal Electrode 22 Thick Film Conductor 23 Thin Film Conductor

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01G 13/00 391 H01F 15/10 C

Claims (8)

[Claims] An internal electrode (1) comprising a conductive film inside.
5) a chip body (13) on which (15)... Are formed;
The chip-shaped electronic component has external electrodes (14) and (14) each formed of a conductive film formed at an end of the chip body (13) where the internal electrodes (15), (15)... Are exposed. The outer electrodes (14) and (14) are
The thick film conductor (22) formed on the end face of the chip body (13) with the exposed 5), (15).
A chip-shaped electronic component which is electrically connected to 2) and comprises at least a thin-film conductor (22) formed on an end peripheral surface of a chip body (13). 2. A method according to claim 1, wherein the thick film conductor is formed of a chip body.
The chip-shaped electronic component according to claim 1, wherein the chip-shaped electronic component is formed by baking a conductive paste applied to the end face of (3). 3. The thin-film conductor (23) comprises a chip body (1).
The chip-shaped electronic component according to claim 1, wherein the chip-shaped electronic component is formed of a plating film applied to an end of 3). 4. The ceramic layer (21) is formed with conductor films (16) and (17) exposed on an end face of the chip body (13) and a peripheral face adjacent thereto. 4. The chip-shaped electronic component according to 3. 5. A step of obtaining a chip body in which internal electrodes (15), (15)... Are formed,
(15) forming external electrodes (14) and (14) made of a conductive film at the ends of the chip body (13) where the exposed electrodes are exposed. ), (15) ... exposed chip body (1
After the step of forming the thick film conductor (22) on the end face of 3) and the step of forming the thick film conductor (22), the same thick film conductor (2) is formed.
Forming a thin film conductor (23) on at least the peripheral surface of the end of the chip body (13) so as to conduct with 2). 6. The method according to claim 5, wherein the step of forming the thick-film conductor is a step of applying a conductive paste to an end surface of the chip body and baking the conductive paste. Electronic components. 7. The chip-shaped electronic component according to claim 4, wherein the step of forming the thin-film conductor (23) is a step of plating an end portion of the chip body (13). 8. An internal electrode (1) is provided on a ceramic layer (21).
5), (15)... At the same time as forming the conductor films (16) and (17) exposed on the end surface of the chip body (13) and the peripheral surface adjacent thereto at the same ceramic layer (21). The chip-shaped electronic component according to claim 7, wherein: