JPH088196B2 - How to attach conductive paste for external electrodes - Google Patents

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In an electronic component having an external electrode, for example, a laminated ceramic capacitor, a plurality of unsintered sheets printed with a conductive paste film serving as an internal electrode are laminated, and the laminated sheet is formed into a prism. After cutting into a shape to obtain an unfired chip component, a conductive paste serving as an external electrode is attached to an end of the chip component, and the chip component after the paste is attached is fired at an appropriate temperature. It is manufactured by firing an unfired ceramic and firing each paste. Depending on the capacitor, after firing the unfired chip, a conductive paste for external electrodes may be used.
There are also those in which a strike is attached and the baking is performed.

As shown in FIGS. 9 to 11, the conductive paste attaching step in the above manufacturing process is performed by the conductive paste P. As shown in FIG.
The chip component C is vertically lowered toward the tank S in which the conductive paste P is placed up to a predetermined adhesion size.
It is carried out by immersing the chip component C in the substrate and then pulling up the chip component C. As shown in FIG.
As shown in FIG. 5, the conductive paste P is attached from the end surface to the peripheral surface.

[0004]

However, in the conventional method of attaching the 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 easily generated, and the conductive paste is also formed.
There is also a problem that the bubble E does not separate from the end surface Ca until the immersion is completed due to the influence of the viscosity of the strike P, and the bubble E remains in the adhesion paste P. The residual bubbles cause formation of a porous portion in the external electrode after baking and impede electrical continuity between the external electrode and the internal electrode.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for adhering a conductive paste in which bubbles are not formed in the adhering paste. It is in.

[0006]

In order to achieve the above object , the present invention provides a conductive paste surrounding the end face of a chip component.
Japanese a step of relatively moving in the tangential direction of the application roller which is supplied to the surface, by comprising a step of pulling after soaking the end of the chip component in the conductive paste in the tank
It is a sign .

[0007]

In the present invention, the mountain-shaped conductive paste is attached to the end face of the chip component in the attaching step by the coating roller, and the surface of the conductive paste previously attached in the attaching step by dipping. To the peripheral surface of the chip component, a conductive paste is further attached.

[0008] That is, in adhesion process by the coating roller may push the air around the attachment head portion of the end face by sequentially contacting the conductive paste toward the rear end face of the chip component to the outside, also the second attachment by immersion In the process, the conductive paste can be brought into contact with each other in order from the apex portion of the mountain-shaped portion to push out the air around the mountain-shaped portion to the outside, so that bubbles are not formed in the paste adhered in both processes.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention, which is an example of a monolithic ceramic capacitor, will be described below with reference to FIGS. In the drawings, the same reference numerals are used for parts having the same configurations as those of the conventional example.

The conductive paste attaching method according to the present invention comprises a first attaching step using a coating roller and a second attaching step using dipping.
And an attaching step. First, the first attaching step will be described with reference to FIGS. 1 to 3.

In the figure, C is a chip component to be attached, which corresponds to a non-fired or fired chip component. An unfired chip component is obtained by laminating a plurality of unfired sheets printed with a conductive paste film to be internal electrodes as in the conventional example, and cutting the laminated sheet into a prism shape. ,
On the other hand, the chip component after firing is obtained by firing an unfired chip component at an appropriate temperature. The conductive paste used as the internal electrode is a mixture of metal powder and binder in a predetermined weight ratio.

Reference numeral R denotes a coating roller which is rotated in one direction by a motor or the like and has a diameter larger than the end surface of the chip component C. A conductive paste P is sequentially supplied to the peripheral surface of the coating roller R with a constant thickness by a supply device (not shown). The conductive paste supplied here serves as an external electrode, and is a mixture of metal powder and binder in a predetermined weight ratio.

The first attaching step by the coating roller is carried out by moving the end surface of the chip component C in the tangential direction of the coating roller R as shown in FIG. Although only one chip component C is shown in the drawing, in practice, a large number of chip components C are arranged on a holding plate or the like at the same height and horizontally moved to the lower side of the coating roller R. The same process is performed.

In the first attaching step, as shown in FIG. 2, the conductive paste P is brought into contact with the rear end of the end face Ca of the chip component C in order from the moving front part toward the rear, whereby the air around the end face is externally exposed. Therefore, bubbles are not formed on the end surface Ca of the chip component C. After the completion of the first attaching step, the conductive paste P is attached to the end surface Ca of the chip component C in a mountain shape (first attaching layer P1) as shown in FIG.

Next, the second attaching step will be described with reference to FIGS.

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

The second attaching step by immersion is shown in FIGS.
As shown in FIG. 1, the chip part C is vertically lowered toward the tank S with the first adhesion layer P1 facing downward, and its end is dipped in the conductive paste P to a predetermined adhesion size, and then the chip. This is done by pulling up the part C. Although only one chip component C is shown in the drawing, the same process is actually carried out by arranging a large number of chip components C on a holding plate or the like at the same height and moving them up and down.

In the second attaching step, as shown in FIG. 5, the conductive paste P is sequentially contacted from the top portion of the first attaching layer P1, whereby the air around the first attaching layer is pushed out to the outside. Therefore, no bubbles are formed on the surface of the first adhesion layer P1. After the second attaching step is completed, as shown in FIG. 8, the conductive paste P (second attaching layer P2) is attached from the surface of the first attaching layer P1 to the peripheral surface of the chip component C. In the same manner as above, the conductive paste P is attached to the other end of the chip component C as well.

That is, according to the above adhesion method, the coating roller
In the attaching step by the la, the conductive paste P can be brought into contact with the moving front portion of the end surface Ca of the chip component C in order from the rear to push out the air, and in the second attaching step by dipping, the mountain shape is formed. Since the conductive paste P can be brought into contact with each other in order from the apex portion of the first attachment layer P1 to push out the air to the outside, no bubbles are formed in the paste attached in both steps. .

In the examples, the same conductive paste was used in the first and second attaching steps. However, in each step, a conductive paste containing different kinds of metal powder or a conductive paste having different viscosities is used. A conductive paste may be used, and the shape of the chip component is not limited to the prismatic shape, but may be a cylindrical shape or the like.

Although the present invention is applied to the monolithic ceramic capacitor in the embodiments, it is needless to say that the present invention can be applied to other electronic parts as long as it has a similar external electrode.

[0022]

As described above in detail, according to the present invention, the conductive paste is adhered while the air around the adhering surface is pushed out in both the adhering step by the coating roller and the adhering step by dipping. As a result, bubbles are not formed in the paste applied in both steps.

[Brief description of drawings]

FIG. 1 is a schematic side view showing a first attaching step.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a cross-sectional view of essential parts of the chip part after the first attaching step is completed.

FIG. 4 is a schematic side view showing a second attaching step.

FIG. 5 is a schematic side view of the same.

FIG. 6 is a schematic side view of the same.

FIG. 7 is a schematic side view of the same.

FIG. 8 is a cross-sectional view of the essential parts of the chip part after the completion of the second attaching step.

FIG. 9 is an attachment process diagram showing a conventional example.

[Fig. 10] Same attachment process diagram

[Fig. 11] Same adhesion process diagram

FIG. 12 is a cross-sectional view of a main part of a chip component after completion of attachment.

[Explanation of symbols]

C ... Chip component, Ca ... End surface, R ... Coating roller, S ...
Tank, P ... Conductive paste, P1 ... First adhesive layer, P2 ... Second adhesive layer.

Claims (1)

[Claims] 1. A conductive paste surrounds the end surface of a chip component.
An external electrode comprising: a step of relatively moving the coating roller supplied to the surface in a tangential direction ; and a step of immersing an end portion of the chip component in a conductive paste in a tank and then pulling it up. Method of applying conductive paste for use.