JPS5972715A - Laminated condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is a sheet in which dielectric paste and electrode paste are alternately printed, or a dielectric sheet with electrode paste entirely printed in advance, which is laminated in multiple layers, and then fired. The present invention relates to a multilayer capacitor manufactured by M manufacturing.

Conventional Structure and Problems Therein FIG. 1 is a sectional view of a green sheet of a multilayer capacitor formed in the form of a large number of sheets.

In FIG. 1, the internal electrodes 2 are formed by printing a conductive paste such as palladium to a thickness of about 5 microns. Figure 1B shows the pieces cut into individual pieces along the dot-dashed line.

As shown in the first diagram, the external electrode 3 is formed on the cut surface and connected to the internal electrode 2. However, during cutting, the dielectric layer 1 is plastically deformed and becomes crispy, causing the internal electrode 2 to It may be hidden. Therefore, before firing, the dielectric layer is polished by barrel machining or the like, and an electrode extraction process is performed to ensure that the internal electrode 2 protrudes onto the cut surface as shown in FIG. 1C. Thereafter, it is fired and the external electrode 3 is attached as shown in the first diagram to form a completed multilayer capacitor.

In multilayer capacitors, how reliably the internal and external electrodes are connected is a major factor in determining reliability. For example, if we take a chip capacitor as an example, even if each layer of the internal electrodes formed in multiple layers is electrically connected to the external electrodes and a specified capacitance is produced, if the connection area is small and the conductor resistance is high, When used in FM oscillation circuits, etc., oscillation failures occur due to a decrease in the Q value. Therefore, it is necessary to reliably connect each layer of the internal electrode to the external electrode over a wide area.

3be, -zo Conventionally, the internal electrode 2 is around 5 microns, and the dielectric layer is 20~
It is formed to a thickness of about 100 microns. Therefore, even if you try to remove the internal electrodes by polishing the dielectric layer using barrel processing, etc., it takes a long time because the dielectric layer is thicker, and since the internal electrodes are thin at about 5 microns, the cut surface It was extremely difficult to expose 100% of the cross section of the electrode. Furthermore, after the electrodes are exposed by barrel processing, they are fired, but this firing causes the internal electrodes to shrink and sink into the dielectric layer, making it even more difficult to connect them with external electrodes. There is. In addition, since the internal electrodes are printed using thick film printing methods such as palladium or other conductor paste If silk screen printing,
The electrode film thickness may vary due to paste viscosity, screen mesh, emulsion thickness, squeegee angle, printing pressure, and many other factors, and scratches may occur in some areas.

The internal and external electrodes are connected due to the instability factors mentioned above, but conventional multilayer capacitors are mainly chip capacitors with wide internal electrodes, as shown in Figure 2. It was a useful use.

If the width of the electrode was wide, even if some parts of the same layer were not connected, it would not be a big problem. However, as chip capacitors have become smaller in recent years, and in multi-capacitors with many capacitors built into a small board as shown in Figure 2B, the width of the lead-out portion of the internal electrode is becoming narrower and narrower. , the reliability of the connection with the external electrode decreases. Also, Figure 2B
In the case of a multi-capacitor like , Ru is placed on this board.
It is also conceivable to form a thick film resistor fired at about 850° C. such as O2. When considering a process in which multilayer capacitors are subjected to high temperatures later on, there is a problem in that conventional multilayer capacitors cannot guarantee sufficient reliability.

OBJECTS OF THE INVENTION The present invention eliminates the above-mentioned conventional drawbacks and provides an excellent multilayer capacitor with a simple structure and high reliability.

Arrangement of the Invention Page 5 [0016] According to the present invention, the vicinity of the connection part of the internal electrode with the external electrode is formed thicker than other parts, thereby making the connection with the upper and lower external electrodes more secure and improving reliability. It is composed of

DESCRIPTION OF EMBODIMENTS FIG. 3 is a cross-sectional view of an embodiment of a multilayer capacitor of the present invention formed in the form of a multilayer capacitor, and FIGS. This figure shows the shape of the electrode 2. In FIGS. 3 and 4, the internal electrodes 2 shown in FIGS. 4A and 4B are alternately stacked to form a structure similar to a person in FIG. Then, it is separated into individual pieces by cutting along the dot-dash line in FIG. In conventional multilayer capacitors, internal electrodes are printed with the same thickness on all parts, whether by printing or sheeting.

In the present invention, as shown in FIGS. 3 and 4, the internal electrodes 2 in the connection vicinity 4 with the external electrodes 3 are coated over the entire thickness of the internal electrodes 2, or by manufacturing innovations, etc., the internal electrodes and other parts are I try to print thickly.

6 vanes The subsequent process is the same as that described in the conventional example.

Note that the shape and dimensions of the area 4 near the connection part where the film thickness is increased are as follows:
The optimum shape may be selected while considering the relationship with the overall shape of the internal electrodes. In addition, as a method of thickening the area near the connection part 4, if printing is repeated two or more times, use a paste different from the first paste used to print the entire internal electrode (for example, a paste with good adhesion to the dielectric material, or a paste with barrel polishing). You may also apply a coating (one that is not easily scratched).

Effects of the invention (1) Since the internal electrode 3 in the vicinity of the connection part 4 is thicker than other parts, the electrode is easily exposed by short barrel machining, and it does not have a partially chipped shape as in the conventional case. Fully exposed.

(Additionally, with conventional internal electrodes of the same thickness, the electrodes shrink during the subsequent firing process, and the electrodes that were taken out through barrel processing may sink into the dielectric material.
According to the invention 7 t-, :.

Since only the part 4 near the connection part is thick, this creates a wedge effect,
A sufficient connection area with external electrodes can be secured without penetrating into the dielectric material.

(3) Different paces) The effect can be further enhanced by applying multiple coats.

(4) And due to the effects of (1), (2), and (3) above,
Compared to conventional multilayer capacitors, the connection reliability between internal and external electrodes can be dramatically improved.

(5) In addition, by improving connection reliability, the width of the electrode lead-out part can be narrowed, and in multi-capacitors etc. where component shapes are miniaturized, the degree of integration can be increased and the number of lead-out terminals can be increased. becomes easier.

(6) To increase the thickness of the internal electrode in order to increase the reliability of the connection, the entire internal electrode is made thicker, or in the case of the sheet method, electrodes are printed on both sides of the dielectric sheet and then There is also a method of stacking layers, but this increases the thickness of the multilayer capacitor and requires the use of a large amount of expensive conductive paste, which increases costs. However, in the present invention, a large effect can be achieved with a slight increase in the amount of paste.

(F) With conventional multilayer capacitors, it was difficult to perform the process of forming a thick film resistor on the multilayer capacitor because the connection between the internal and external electrodes would come off when exposed to high temperatures. There is no problem even after repeated firing at 850° C., which has the advantage of further expanding the range of applications in which multilayer capacitors can be used as substrates.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a green sheet that constitutes a conventional multilayer capacitor, Figure 1B is a cross-sectional view of an individual piece cut along the dot-dashed line in Figure 1, and Figure 1C is Figure 1B. Figure 1 is a cross-sectional view and right side view of a completed conventional multilayer capacitor, Figure 2 is a perspective view of a chip-shaped multilayer capacitor, and Figure 2B is a perspective view of a multi-capacitor. , Figure 3 is a cross-sectional view of one embodiment of the green sheet constituting the multilayer capacitor of the present invention, Figure 3B is a cross-sectional view on page 9 of an individual piece cut along the dashed-dotted line in Figure 3, Figure 3C is a sectional view and right side view of one embodiment of the completed multilayer capacitor of the present invention, Figure 4 is a cross-sectional view and a right side view
FIG. 3 is a front view showing the internal electrodes of a person. 1... Dielectric layer, 2... Internal electrode, 3
. . . External electrode, 4 . . . Connection portion of internal electrode to external electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person
1 Figure 2 2 tA) IB)

Claims (1)

[Claims] A multilayer capacitor characterized in that the vicinity of the connection part of the internal electrode with the external electrode is formed thicker than other parts of the upper and lower internal electrodes.