JPH0869950A - Formation of outer electrode of ceramic electronic part - Google Patents

Abstract

PURPOSE: To obtain a ceramic electronic part having an outer electrode which has a nearly uniform film thickness as a whole and is free from voids. CONSTITUTION: An end of a ceramic element is dipped in and pulled from a paste layer of electrode materials formed on a surface plate for forming an outer electrode paste film 3 on the end of the ceramic element 2. The unsolidified outer electrode past film 3 which is formed on the end of the ceramic element 2 is pressed to a flat plate 6 on which a mold-release agent layer 5 for this outer electrode paste film 3 is formed, the film 3 is pushed up, and in this condition, ultrasolic vibration is applied to the outer electrode paste film 3. This makes film thickness of the outer electrode paste film 3 formed on the end of the ceramic element 2 uniform, then, drying is performed. After the outer electrode paste film 3 is solidified, the ceramic element 2 is taken out of the flat plate 6 and baked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming an external electrode of a ceramic electronic component, and more particularly to an external electrode of a ceramic electronic component having an external electrode at an end thereof, such as a multilayer capacitor, a chip resistor, a chip inductor and the like. It relates to a forming method.

[0002]

2. Description of the Related Art FIGS. 1A and 1B are explanatory views showing a conventional method of forming an external electrode of an electronic component, showing a step of immersing a ceramic element in an electrode material paste layer and pulling it up. FIG. 2 is an enlarged sectional view of an essential part showing the state of the external electrode paste film obtained in the step of FIG. As can be seen from FIG. 1, the end portion of the ceramic element 2 is dipped in the electrode material paste layer 1 formed on the surface plate 9 in the direction of the arrow and pulled up.
As a result, the external electrode paste film 3 is formed on the end portion of the ceramic element 2, and then the external electrode paste film 3 is formed.
Is fired to form external electrodes.

[0003]

However, when such a method is used, the external electrode paste film attached to the end of the ceramic element 2 pulled up from the electrode material paste layer 1 hangs down by its own weight, as shown in FIG. In addition, the film thickness T of the lower surface of the end of the ceramic element 2 may become too thick, or the film thickness t of the peripheral portion of the end of the ceramic element 2 may become too thin. Further, when the ceramic element 2 is immersed in the electrode material paste layer 1, air on the lower surface of the end portion of the ceramic element 2 may be trapped, which causes bubbles in the external electrode paste film 3 on the lower surface of the end portion of the ceramic element 2. As a result, voids may be generated in the external electrode after firing.

In a ceramic electronic component having such an external electrode, moisture easily enters from a portion having a thin film thickness or a portion where a void exists, and if it remains, the insulation resistance may be deteriorated. Therefore, when this ceramic electronic component is subjected to a moisture resistance test or when the surface of the external electrode is subjected to wet electrolytic plating, moisture or a plating solution penetrates into the ceramic element 2 and deteriorates the reliability of the electronic component. .

Therefore, a main object of the present invention is to provide a method for forming an external electrode for a ceramic electronic component, which has a film thickness which is substantially uniform as a whole and in which voids are less likely to occur.

[0006]

According to the present invention, an end portion of a ceramic element is immersed in an electrode material paste layer formed on a surface plate and pulled up to form an external electrode paste film on the end portion of the ceramic element. The external electrode paste film before solidification formed at the end of the ceramic element is pressed against the flat plate on which the release agent layer for the external electrode paste film is formed, and the film is pushed up. By applying ultrasonic vibration to the external electrode paste film, the film thickness of the external electrode paste film formed on the end portion of the ceramic element is adjusted, and then dried to solidify the external electrode paste film, and then the ceramic A method for forming an external electrode of a ceramic electronic component, comprising taking out an element from the flat plate and firing the element.

[0007]

The external electrode paste film attached to the end of the ceramic element pulled up from the electrode material paste layer formed on the surface plate hangs by its own weight. Therefore, the external electrode paste film before solidification formed at the end of the ceramic element is pressed against the flat plate on which the release agent layer for the external electrode paste film is formed, and the sagging film is pushed up, By applying ultrasonic vibration to the external electrode paste film, the fluidity of the external electrode paste film is improved, the film thickness of the external electrode paste film is adjusted, and a substantially uniform film thickness is obtained. Bubbles in the electrode paste film are pushed out. Furthermore, by drying the external electrode paste film while being pressed against the flat plate, the external electrode paste film can be solidified so that the shape of the film does not collapse. Thereafter, even if the ceramic element in which the external electrode paste film is solidified is taken out from the plane plate, the external electrode paste film is not taken on the plane plate because the release agent is applied on the plane plate. Absent. By firing the external electrode paste film thus formed, it is possible to obtain a ceramic electronic component having an external electrode having a substantially uniform film thickness as a whole and having no void. Therefore, it is possible to suppress the infiltration of moisture and the plating liquid into the ceramic element from the external electrodes.

[0008]

Therefore, the ceramic electronic component of the present invention can suppress the infiltration of moisture and plating liquid into the inside of the ceramic element even when the moisture resistance test is performed or the surface of the external electrode is subjected to wet electrolytic plating. Therefore, highly reliable electronic components can be obtained.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be clarified by describing embodiments with reference to the drawings.

First, in the same manner as in the prior art shown in FIG. 1, the end portion of the ceramic element 2 is immersed in the electrode material paste layer 1 for the external electrode on the surface plate 9 and pulled up to make the ceramic element 2
The external electrode paste film 3 is applied to the end portions of. A ceramic element for a multilayer capacitor is used as the ceramic element 2. The ceramic element for a multilayer capacitor is formed, for example, by stacking a green sheet made of a dielectric ceramic material and an internal electrode material and firing the stacked layers. In this case, the plurality of internal electrodes face each other via the dielectric porcelain,
Further, they are formed so as to be alternately exposed at both ends of the dielectric ceramic. As the electrode material paste, for example, a mixture of silver, a glass material and a solvent is used. The thickness of the electrode material paint layer 1 is set according to the dimension of the external electrode applied to the side surface adjacent to the lower surface of the end portion of the ceramic element 2. In this way, the external electrode paste film 3 formed on the end portion of the ceramic element 2 is formed as shown in FIG.
As shown in FIG. 5, the bubbles 4 are present therein, and the film thickness t of the peripheral portion of the lower surface of the end portion of the ceramic element 2 is thin.

Next, as shown in FIG. 3, the ceramic element 2 having the external electrode paste film 3 formed thereon is placed on a flat plate 6 having a release agent layer 5 for the external electrode paste film formed thereon, as shown in FIG. The external electrode paste film 3 before being hung down is pressed against the lower surface of the end portion of the element 2 to push up the hung film. The release agent has poor wettability with respect to the external electrode paste, and is selected from, for example, silicon resin, fluororesin, stearates, waxes and the like.

After that, as shown in FIG. 4, an ultrasonic vibrator 7 is brought into contact with the flat plate 6 to apply vibration. As a result, ultrasonic vibration is applied to the external electrode paste film 3 pressed against the external electrode paste film 3 through the flat plate 6, so that the external electrode paste film 3 has good fluidity, and the film thickness of the external electrode paste film is increased. Is adjusted, and even if bubbles are present in the external electrode paste film, they are extruded to the outside. In addition,
The ultrasonic vibration frequency used is about several tens KHz to several hundreds KHz, and is appropriately determined based on the viscosity of the external electrode paste, the dimensions of the ceramic element 2, and the like.

Thereafter, in the drying oven 8 shown in FIG. 4, the external electrode paste film 3 is dried and solidified while being pressed against the plane plate 6. When the drying is completed, the drying oven 8
Then, the ceramic element may be taken out from the flat plate 6. In this case, since the release agent is applied to the flat plate 6, the external electrode paste film 3 is not taken by the flat plate 6. The drying conditions are electrode material paste 1
It is determined appropriately depending on the type of solvent used in. Also,
As the release agent used, at least a release agent that does not lose its releasability with respect to the external electrode paste film 3 even after this drying step is completed is used.

As a result, the obtained external electrode paste film has a film thickness T at the end portion of the ceramic element 2 and a film thickness t at the peripheral portion of the lower surface of the ceramic element 2 as shown in FIG. The difference is reduced, and the external electrode paste film 3 having a substantially uniform thickness is formed as a whole. In addition, no bubbles remain in the external electrode paste film 3.

Therefore, by firing the above-mentioned external electrode paste film 3, it is possible to obtain a ceramic electronic component having an external electrode having a substantially uniform film thickness and having no voids. Therefore, the ceramic electronic component formed with the external electrode of this embodiment, even if subjected to a humidity resistance test, or wet electrolytic plating on the surface of the external electrode, moisture or plating liquid is unlikely to enter the inside of the ceramic element, A highly reliable electronic component can be obtained. It goes without saying that the method for manufacturing the ceramic electronic component is not limited to the multilayer capacitor and can be applied to any electronic component having an external electrode such as a chip resistor and a chip inductor.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a conventional method of forming an external electrode of an electronic component.

FIG. 2 is an enlarged sectional view of an essential part showing a state of an external electrode paste film obtained in the step of FIG.

FIG. 3 is an enlarged sectional view of an essential part showing a state in which an external electrode paste film is pressed against a flat plate on which a release agent is formed.

FIG. 4 is an explanatory view showing a step of applying ultrasonic vibration to the external electrode paste film and then drying it.

FIG. 5 is an enlarged sectional view of an essential part showing a state of an external electrode paste film obtained by the present invention.

[Explanation of symbols]

 1 Electrode Material Paste Layer 2 Ceramic Element 3 External Electrode Paste Film 4 Bubbles 5 Release Agent Layer 6 Plane Plate 7 Ultrasonic Transducer 8 Drying Furnace 9 Surface Plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication H01G 4/252

Claims (1)

[Claims] 1. An end portion of a ceramic element is dipped in an electrode material paste layer formed on a surface plate and pulled up to form an external electrode paste film on the end portion of the ceramic element, and a release from the external electrode paste film is performed. The external electrode paste film before solidification, which is formed at the end portion of the ceramic element, is pressed against the flat plate on which the agent layer is formed, the film is pushed up, and ultrasonic vibration is applied to the external electrode paste film in that state. By adjusting the film thickness of the external electrode paste film formed at the end of the ceramic element, and then drying to solidify the external electrode paste film, the ceramic element is taken out from the flat plate. A method for forming an external electrode for a ceramic electronic component, which comprises firing.