JPH04263409A - Method of adhering conductive paste for outer electrode - Google Patents

Abstract

PURPOSE:To provide the method of adhering conductive paste in such a manner that no bubbles are generated in the adhesive paste. CONSTITUTION:As conductive paste is stuck by conducting a process in which the edge face Ca of a chip part C is moved in tangential direction of a coating roller R with which conductive paste P is fed to the circumferential surface, and another process in which the edge part of the above-mentioned chip part C is picked up after it has been dipped into the conductive paste C in a vessel S, the conductive paste can be adhered while the air on the circumference of the adhesion surface is being pushed out to outside in the adhesion process by the coating roller and in the adhesion process by dipping, and bubbles are not generated in the adhering paste in both processes.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for applying a conductive paste for external electrodes, which is useful in manufacturing electronic parts having external electrodes.

0002

[Prior Art] Electronic components having external electrodes, such as multilayer ceramic capacitors, are manufactured by laminating a plurality of unfired sheets printed with conductive paste films that serve as internal electrodes, and then forming the laminated sheets into a prismatic shape. After cutting into shapes to obtain unfired chip parts, a conductive paste that will become external electrodes is attached to the ends of the chip parts, and the chip parts with the paste attached are fired at an appropriate temperature. It is manufactured by firing unfired ceramic and baking each paste. Some capacitors are designed such that a conductive paste for external electrodes is attached and baked after the unfired chip is fired.

[0003] In the process of applying the conductive paste in the above manufacturing process, as shown in FIGS. 9 to 11, the conductive paste P is
The chip component C is vertically lowered toward the tank S in which the chip component C is housed, and the conductive paste P is applied to the end of the chip component C to a predetermined adhesion dimension.
This is done by immersing the chip component C in water and then pulling it up. At the end of the chip component C after dipping, there is a mark shown in FIG.
As shown in , a conductive paste P is applied from the end surface to the circumferential surface.

0004

[Problems to be Solved by the Invention] However, in the conventional method of applying conductive paste by dipping, during the descent,
In particular, when the end surface Ca of the chip component C touches the surface of the conductive paste P, bubbles E are likely to be generated, and the conductive paste
The problem is that the viscosity of the paste P also affects the air bubbles E, so that the air bubbles E do not leave the end surface Ca until the immersion is completed, and the air bubbles E remain in the adhered paste P. These residual bubbles may form porous portions in the external electrodes after baking, or may impede electrical conductivity between the external electrodes and the internal electrodes.

The present invention has been made in view of the above-mentioned problems, and its object is to provide a method for adhering a conductive paste without forming bubbles in the adhering paste. It is in.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a step of moving an end surface of a chip component in a tangential direction of a coating roller whose peripheral surface is supplied with conductive paste; The conductive paste is attached by immersing the end of the chip component in the conductive paste in the tank and then pulling it up.

[0007]

[Operation] In the present invention, conductive paste is deposited in a mountain shape on the end face of the chip component in the deposition process using a coating roller, and the surface of the conductive paste previously deposited in the deposition process by dipping. A conductive paste is further applied to the peripheral surface of the chip component.

That is, in the adhesion process using the applicator roller, the conductive paste can be brought into contact with the end face of the chip component sequentially from the top of the movement toward the rear, and the air around the end face can be pushed out. In the second adhesion process, the air around the chevron-shaped part can be pushed out by contacting the conductive paste starting from the apex of the chevron-shaped part to the outside, so that no air bubbles are formed in the paste deposited in both processes. is never formed.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention, using a multilayer ceramic capacitor as an example, will be described below with reference to FIGS. 1 to 8. In the drawings, the same reference numerals are used for parts having the same configuration as those of the conventional example.

The method of applying a conductive paste according to the present invention comprises a first adhesion step using an applicator roller and a second adhesion step using dipping. First, referring to FIGS. 1 to 3, the first
The adhesion process will be explained.

[0011] In the figure, C indicates a chip component to be attached, which corresponds to an unfired or fired chip component. Unfired chip parts are obtained by laminating multiple unfired sheets printed with conductive paste films that serve as internal electrodes and cutting the laminated sheets into prismatic shapes, as in the conventional example. ,
On the other hand, a fired chip component can be obtained by firing an unfired chip at an appropriate temperature. Further, the conductive paste used as the internal electrode is a mixture of metal powder and a binder in a predetermined weight ratio.

R is a coating roller rotated in one direction by a motor or the like, and has a diameter larger than the end surface of the chip component C. The conductive paste P is sequentially supplied to the circumferential surface of the application roller R at a constant thickness by a supply device (not shown). The conductive paste supplied here becomes the external electrode, and is a mixture of metal powder and binder in a predetermined weight ratio.

The first adhesion step using the applicator roller is carried out by moving the end face of the chip component C in the tangential direction of the applicator roller R, as shown in FIG. Although only one chip component C is shown in the drawing, in reality, a large number of chip components C are lined up at the same height on a holding plate, etc., and moved horizontally to the underside of the applicator roller R. The same process is performed.

In this first adhesion step, as shown in FIG. 2, the conductive paste P is brought into contact with the end face Ca of the chip component C in order from the top of the movement towards the rear, thereby causing the air around the end face to be removed from the outside. Therefore, no air bubbles are formed on the end surface Ca of the chip component C. After the first adhesion step is completed, the conductive paste P is adhered in the shape of a mountain (first adhesion layer P1) to the end surface Ca of the chip component C, as shown in FIG.

Next, the second adhesion step will be explained with reference to FIGS. 4 to 8.

In the figure, S is a tank containing conductive paste P. The conductive paste P contained in this tank S is the same as that supplied to the application roller R.

The second attachment step by dipping is shown in FIGS. 4 to 7.
As shown in the figure, the chip component C is vertically lowered toward the tank S with the first adhesive layer P1 facing downward, and after immersing the end portion in the conductive paste P to a predetermined adhesion dimension, the chip component C is lowered vertically toward the tank S. This is done by pulling up part C. Although only one chip component C is shown in the drawing, the same process is actually performed by arranging a large number of chip components C at the same height on a holding plate or the like and moving them up and down.

In this second adhesion step, as shown in FIG. 5, the first adhesion layer P1 is brought into contact with the conductive paste P in order starting from its apex, thereby pushing the air around the first adhesion layer to the outside. Therefore, no air bubbles are formed on the surface of the first adhesive layer P1. After the second adhesion step is completed, a conductive paste P (second adhesion layer P2) is applied from the surface of the first adhesion layer P1 to the circumferential surface of the chip component C, as shown in FIG. Conductive paste P is also applied to the other end of the chip component C in the same manner as above.

That is, according to the above-mentioned adhesion method, the coating roller
In the adhesion process using a roller, the conductive paste P can be brought into contact with the end surface Ca of the chip component C in order from the top of the movement towards the rear to push the air out. Since the conductive paste P can be brought into contact with the top of the first adhesive layer P1 in order to push air out, air bubbles will not be formed in the paste that is deposited in both steps. .

In the example, the same conductive paste was used in the first and second adhesion steps, but in each step, conductive pastes containing different types of metal powder or conductive pastes with different viscosities were used. In addition, the shape of the chip component is not limited to a prismatic shape, but may also be a cylindrical shape or the like.

Further, although the present invention has been applied to a multilayer ceramic capacitor in the embodiment, it goes without saying that it can be applied to other electronic components as long as they have similar external electrodes.

[0022]

As described in detail above, according to the present invention, conductive paste can be applied while pushing out the air around the adhesion surface in both the adhesion process using the applicator roller and the adhesion process by dipping. As a result, air bubbles are not formed in the paste deposited in both steps.

[Brief explanation of the drawing]

[Fig. 1] Schematic side view showing the first attachment step

[Figure 2] Partially enlarged view of Figure 1

[Figure 3] Cross-sectional view of the main parts of the chip component after the first attachment process

[Fig. 4] Schematic side view showing the second adhesion step

[Figure 5] Schematic side view of the same

[Fig. 6] Schematic side view of the same

[Figure 7] Schematic side view of the same

[Figure 8] Cross-sectional view of the main parts of the chip component after the second attachment step

[Figure 9] Adhesion process diagram showing a conventional example

[Figure 10] Adhesion process diagram

[Figure 11] Adhesion process diagram

[Figure 12] Cross-sectional view of the main parts of the chip component after completion of adhesion

[Explanation of symbols]

C...chip component, Ca...end face, R...application roller, S...tank, P...conductive paste, P1...first adhesion layer, P2...second
Adhesive layer.

Claims (1)

[Claims] 1. A step of moving an end surface of a chip component in the tangential direction of an applicator roller whose peripheral surface is supplied with conductive paste, and moving the end surface of the chip component to the conductive paste in a bath. 1. A method for attaching a conductive paste for external electrodes, comprising the steps of immersing it in water and then pulling it up.