JPS61144812A - Capacitance adjustment for laminated ceramic capacitor - 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 This invention relates to a method for adjusting capacitance after obtaining a multilayer ceramic capacitor. Note that "capacitance adjustment" as used in this invention is not limited to the concept of "capacitance trimming" in which a minute capacitance Im is adjusted to a completed multilayer ceramic capacitor, but also refers to a capacitance that changes the capacitance over a wider range. Also includes ffi adjustment.

2. Description of the Related Art Conventionally, one method for adjusting the capacitance of a completed multilayer ceramic capacitor is capacitance trimming using a sandplast method. That is, this method reduces the effective area of the internal electrodes by sandblasting the outer surface of the multilayer ceramic capacitor, making holes that reach the internal electrodes inside, and scraping off part of the internal electrodes.

This method is partially used in the manufacture of multilayer ceramic capacitors that require small capacitance deviations.

In addition, as another method for adjusting the capacitance of a multilayer ceramic capacitor after completion, an inner I! l′! ! There is also a method of adjusting the capacitance by providing a trimming electrode facing one pole and scraping it off by sandblasting or the like.

Problems to be Solved by the Invention Although the two typical conventional capacitance IIW4 adjustment methods described above can be said to be methods suitable for capacitance adjustment in a minute range,
Wide [11i across the area! Not suitable for adjustment.

Furthermore, when cutting the internal electrodes or trimming electrodes, a relatively large mechanical impact is applied to a portion of the multilayer ceramic capacitor. However, since the parts to which such mechanical impact is applied are parts directly involved in capacitance formation, such as internal electrodes and trimming electrodes, it may have an adverse effect on the characteristics of the multilayer ceramic capacitor itself.

Further, particularly in the former method described above, the holes left as a result of trimming are filled with a glass component or the like. Therefore, extra scholarship is required, and even if the holes are filled, reliability problems will remain.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for adjusting the capacitance of a multilayer ceramic capacitor, which can easily adjust the capacitance over a wider range without adversely affecting the characteristics of the multilayer ceramic capacitor itself. It is.

Means for Solving the Problems In this invention, when a lead electrode extending from a part of the internal electrode extending inside the laminate toward the surface of the laminate is electrically connected to an external electrode on the surface of the laminate, external electrode,
It is characterized in that a portion of the extraction electrode that comes into contact with a specific one is removed, thereby cutting off the electrical connection between the external electrode and the specific internal electrode.

Effects In this invention, by partially removing the external electrode,
This prevents all of the specified number of internal electrodes from contributing to capacitance formation. Therefore, the range of capacity flk adjustment is widened, and in extreme terms, capacity adjustment is possible in the range of 0 to 100%. Furthermore, in the present invention, since the connection portion between the external electrode and the extraction electrode that is removed in order to perform such capacitance adjustment is not originally a place that is involved in capacitance formation, by such removal, The characteristics of the multilayer ceramic capacitor itself are not adversely affected. In addition, since there are no holes drilled in the laminate of the multilayer ceramic capacitor, there is no need for a subsequent process of filling the holes, making it possible to adjust the capacitance efficiently and reducing reliability due to the presence of holes. It is also possible to prevent the decline.

Embodiment FIGS. 1 to 5 are diagrams for explaining an embodiment of the present invention.

First, a multilayer ceramic capacitor 1 as shown in FIG.
In manufacturing the ceramic dielectric layers 2 and 3 shown in FIGS. 1 and 2, respectively, are alternately laminated,
Thereafter, by firing them together, a laminate 4 as shown in FIG. 3 is obtained. The state of the internal electrodes formed inside the laminate 4 has the following characteristics.

An internal electrode 5 is formed on one main surface of the ceramic dielectric layer 2 in FIG. 1, and an extraction electrode 6 is formed extending downward from the left end of the lower side of the internal electrode 5 in the drawing. The extraction electrode 6 extends to the edge of the ceramic dielectric layer 2 . On the other hand, an internal electrode 7 is formed on one main surface of the ceramic dielectric layer 3 shown in FIG.
An extraction electrode 8 is formed extending upward from the right end of the upper side in the figure. This extraction electrode 8 also extends to the edge of the ceramic dielectric layer 3. When these ceramic dielectric layers 2.3 are stacked alternately, the dimension W of the laminate 4 matches the widthwise dimension W of the ceramic dielectric layers 2.3, as shown in FIG. , and the number of laminated ceramic dielectric layers 2.3 is selected such that the dimension T of the laminate 4 is larger than the dimension W.

In FIG. 3, therefore, the internal electrodes 5.7 extending within the stack 4 are oriented vertically.

One of the extraction electrodes 6 is exposed and lined up at a position biased to the left side of the lower surface of the laminate 4 in FIG. 3.

On the other hand, the extraction electrodes 8 are exposed and lined up at positions closer to the right side of the upper surface of the laminate 4.

As shown in FIG. 4, external electrodes 9 and 10 are formed on the laminate 4 of FIG. 3. As shown in FIG. The external electrode 9 is the extraction electrode 6
is formed so as to cover the surface of the laminate in the exposed portion. The external electrode 10 is formed to cover the surface of the laminate 4 in the portion where the extraction electrode 8 is exposed.

In this embodiment, the external electrodes 9 and 10 are formed so as to cover each of the opposing end surfaces and the adjacent surfaces of the laminate 1, and cover at least the exposed portions of the extraction electrodes 6.8. It is formed like this. However, as is clear from the fact that the edges 9a and lQa of the external electrodes 9 and 10 extend parallel and obliquely to each other, the external electrodes 9.1
0 is formed only in a narrower area in the portion that does not contact the extraction electrode 6.8. That is, to explain in terms of the surface appearing in FIG. 4, the portion 9b of the external electrode 9
is narrower than the portion 10b of the external electrode 10. This means that the part of the external electrode to be removed (for the external electrode 10, the part 10b) is explained in the diagram.
This is to make it easier to determine. Also,
For example, the external electrode 10 formed to cover the extraction electrode 8 must be formed with a relatively large area in the portion 10b. Therefore, the distance from the portion 9b of the other external electrode 9 tends to become shorter.

If this distance is short, there is a risk of a short circuit when such a multilayer ceramic capacitor 1 is mounted, so it is preferable to make this distance as long as possible. As a means for this, it is effective to narrow the width of the portion 9b of the external electrode 9. Note that the back side of the multilayer ceramic capacitor 1 shown in FIG. 4 has a similar configuration.

The multilayer ceramic capacitor 1, as shown in FIG.
It is mounted on conductive paths 12 and 13 on a suitable circuit board 11 by solder (not shown) or the like.

This multilayer ceramic capacitor 1 can easily adjust the capacitance even in the mounted state shown in FIG. 4.

Referring to FIG. 5, the state of the W4m ceramic capacitor 1 undergoing or having undergone capacitance adjustment is shown. Focusing on the portion 10b of the external electrode 10, a partially removed portion is shown there. As a result, a specific extraction electrode among the extraction electrodes 8, that is, extraction electrodes 8a and 8b, is set to W4i! These lead electrodes 88, 8b are directly exposed on the surface of the body 4.
Electrical connection with the external electrode 10 is broken. Therefore, the multilayer ceramic capacitor 1 in this state has a total capacitance that is reduced by the amount contributed by the internal electrodes 7 connected to the lead electrodes f3a and 8b.

A well-known sandblasting method or laser trimming method can be used to remove a specific portion of the external electrode 10.

Note that when the capacitance is adjusted after mounting the multilayer ceramic capacitor 1, the downward facing surface of the multilayer ceramic capacitor 1 shown in FIG. 4 may be turned up when mounting the multilayer ceramic capacitor 1. Even if this is done, the surface of the extraction electrode 6 in contact with the external electrode 9 will now appear, and similar capacitance adjustment can be performed by partially removing the external electrode 9. therefore,
The multilayer ceramic capacitor 1 as shown in FIG. 4 can be mounted on either the front or the back, and therefore no mounting errors can occur.

As mentioned above, the capacity can be adjusted in the mounted state, so
This multilayer ceramic capacitor 1 is advantageous because the user can easily adjust the capacitance.

6 to 8 show other examples of multilayer ceramic capacitors to which the present invention is applied.

In this example, the ceramic dielectric shown in FIGS. 6 and 7, respectively! 14 and 15 are alternately stacked to form a multilayer ceramic capacitor 16 as shown in FIG.

On one main surface of the ceramic dielectric layer 14 in FIG.
An internal electrode 17 and an extraction electrode 18 extending leftward from the center of the left side of the internal electrode 17 in the drawing are formed. On one main surface of the ceramic dielectric layer 15 in FIG. 7, an internal electrode 19 and an extraction electrode 20 extending rightward from the center of the right side of the internal electrode 19 are formed.

As shown in FIG. 8, when external electrodes 22 and 23 are formed at both ends of the laminate 21, the external electrodes 22 are electrically connected to the extraction electrodes 18, and the external electrodes 23 are connected to the extraction electrodes 18. It will be in a state where it is electrically connected to 20.

In FIG. 8, a portion of the external electrode 23 has been removed, so that the extraction electrode 20a is exposed to the outside. Therefore, the capacitance contributed by the extraction electrode 20a is reduced.

The extraction electrodes 6.7 and 18°19 in the two types of multilayer ceramic capacitors 1 and 16 described above extend with a width narrower than the length of the side of the internal electrodes 5.7 and 17.19 from which the extraction electrodes are drawn. . Therefore, electrical connection with a specific internal electrode can be severed by simply removing a small portion of the external electrode. However, the extraction electrode may extend with the same width as the length of the side of the internal electrode from which the extraction electrode is extracted.

The capacity adjustment method of the present invention is particularly suitable for discontinuous, ie, stepwise, capacity adjustment. Therefore, for example, in the case of a crystal oscillation type watch, it is advantageous to apply the present invention when adjustment is not possible within the variable range of the trimmer capacitor included therein. In addition, the capacitance fiW4 adjustment method according to the present invention can be used not only to adjust the capacitance as so-called capacitance trimming, but also to change the capacitance of individual multilayer ceramic capacitors by changing the degree of removal of external electrodes from the same multilayer ceramic capacitor. Therefore, it is effective for obtaining a wide variety of multilayer ceramic capacitors.

In addition, by making the areas of the internal electrodes included in one multilayer ceramic capacitor different from each other and selecting the internal electrode that is about to be electrically disconnected from the external electrode, the capacitance can be increased.
It is also possible to arbitrarily change the range of change due to the adjustment.

[Brief explanation of the drawing]

1 and 2 are plan views showing ceramic dielectric layers included in a first example of a multilayer ceramic capacitor to which the present invention is applied. Figure 3 is similar to Figures 1 and 2.
It is a perspective view which shows the laminated body obtained by laminating the ceramic 1414 body layer shown in a figure. FIG. 4 is a perspective view showing a multilayer ceramic capacitor obtained using the laminate shown in FIG. 3, and also shows the mounting state of the multilayer ceramic capacitor. Figure 5 shows
5 is a plan view showing a state in which capacitance Im adjustment is being performed or has been performed on the multilayer ceramic capacitor shown in FIG. 4. FIG. 6 and 7 are plan views showing ceramic dielectric layers included in a second example of a multilayer ceramic capacitor to which the present invention is applied. FIG. 8 is a perspective view of a multilayer ceramic capacitor obtained using the ceramic dielectric layers shown in FIGS. 6 and 7, and also shows a state in which capacitance has been adjusted. In the figure, 1.16 is a multilayer ceramic capacitor, 2
．． 3.14.15 is ceramic 1? Electrical resting layer, 4.21 is a laminate, 5, 7, 17.19 is an internal electrode, 6, 8, 18
．． 20 is an extraction electrode, 9.10°22.23 is an external electrode,
11 is a circuit board.

Claims (4)

[Claims] (1) Multiple layers of internal electrodes are stacked with ceramic dielectric layers in between to form a laminate, and an extraction electrode extending from each internal electrode is drawn out to the surface of the laminate, and the exposed portion of the laminate forms a laminate. A method for adjusting the capacitance of a multilayer ceramic capacitor in which an external electrode is formed on the surface of the multilayer ceramic capacitor, the external electrode being removed at a portion in contact with a specific one of the extraction electrodes, whereby the external electrode and the specific internal electrode are removed. A method for adjusting the capacitance of multilayer ceramic capacitors by cutting off the electrical connection with the electrodes. (2) The method for adjusting the capacitance of a multilayer ceramic capacitor according to claim 1, wherein the extraction electrode extends with a width narrower than the length of the side of the internal electrode from which the extraction electrode is drawn. (3) A method for adjusting the capacitance of a multilayer ceramic capacitor according to claim 1 or 2, which is carried out in a state where the multilayer ceramic capacitor is mounted. (4) In the mounted state of the multilayer ceramic capacitor,
Capacity adjustment of a multilayer ceramic capacitor according to claim 3, wherein the internal electrode extends in a direction perpendicular to the surface on which it is mounted, and the extraction electrode is drawn out to a surface on the laminate parallel to the surface on which it is mounted. Method.