JPH081875B2 - Multilayer capacitor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a multilayer capacitor, and more particularly to a multilayer capacitor having an improved internal electrode shape.

[Conventional technology]

When manufacturing a multilayer capacitor, a plurality of ceramic green sheets printed with a conductive paste for forming internal electrodes are stacked, pressure-bonded in the thickness direction, and then integrally sintered to produce a sintered body. In this case, since the multilayer capacitor is quite small, when printing the conductive paste and stacking the ceramic green sheets,
There was no choice but to make a gap. Therefore, conventionally, various methods have been considered in order to reduce printing deviation and stacking deviation.

FIG. 2 is a perspective view for explaining an example of a conventional method for manufacturing a multilayer capacitor. Ceramic green sheet
Conductive pastes 3 and 4 for forming internal electrodes are printed on the upper surfaces of the electrodes 1 and 2 in the illustrated shape, respectively. That is, the conductive pastes 3 and 4 are formed with the same width as the ceramic green sheets 1 and 2, and when the conductive paste 3 and the conductive paste 4 are stacked, they are drawn out to different facing end faces. It is printed. Here, a plurality of ceramic green sheets 1 and 2 are laminated, and external electrodes are provided to the internal electrode lead-out end faces of a sintered body obtained by sintering, to obtain a multilayer capacitor.

In the above-mentioned multilayer capacitor, it is possible to effectively reduce misalignment of the conductive paste and misalignment of the ceramic green sheets 1 and 2. That is, usually, by applying a conductive paste on a relatively large mother ceramic green sheet, by stacking and cutting the laminate,
Individual stacks are obtained. Therefore, when obtaining the individual laminated body in which the ceramic green sheets 1 and 2 of FIG. 2 are laminated, only by cutting the laminated body, it is possible to obtain a laminated structure in which printing deviation and lamination deviation are less likely to occur.

On the other hand, FIG. 3 is a plan sectional view for explaining another example of the conventional multilayer capacitor. Here, the width of the internal electrode 7 drawn out to the other end surface 5b is considerably narrower than that of the internal electrode 6 drawn out to the one end surface 5a of the dielectric ceramics 5.

Therefore, when the conductive paste for forming the internal electrodes 6, 7 is printed, even if the printing position is slightly shifted in the W direction, the ceramic green sheet coated with the conductive paste for forming the internal electrodes 6, 7 Even if there is a slight deviation in the W direction when the layers are laminated, the overlapping area between the internal electrodes 6 and 7 does not change due to such printing deviation and lamination deviation. That is, in this structure, after confirming that print misalignment or stacking misalignment occurs, the width of the internal electrode connected to one potential is relatively widened to thereby reduce the capacitance due to print misalignment or stack misalignment. Variation is prevented.

[Technical problem to be solved by the invention]

In the conventional multilayer capacitor described with reference to FIG. 2, when cutting individual laminates from the mother laminate, the internal electrode forming conductive pastes 3 and 4 hang down by the cutting blade at the cut surface, and the internal electrodes are separated from each other. Could short circuit. Therefore, the thickness of the dielectric ceramic layer between the internal electrodes, that is, the thickness of the ceramic green sheets 1 and 2 cannot be reduced so much, and it is difficult to increase the acquisition capacity.

Further, in the multilayer capacitor of FIG. 3, although the variation in capacitance can be reduced by making the overlapping area constant, the width of the internal electrode 6 having the side margin regions 8 is smaller than that of the internal electrode 6. Narrower width internal electrode 7
Since they are overlapped with each other, the overlapping area between the opposing internal electrodes is very small. Therefore, only a small-capacity capacitor can be obtained for its size.

Therefore, an object of the present invention is to provide a multilayer capacitor having a structure in which variations in electrostatic capacity are small and the acquisition capacity can be effectively increased.

[Means for solving technical problems]

The present invention includes first and second end surfaces facing each other, and first and second end surfaces.
In a dielectric ceramic having a side surface connecting the end surfaces of
A plurality of internal electrodes that are drawn out to the first and second end faces are arranged alternately in the thickness direction, and the first and second end faces have the first and second end faces.
A multilayer capacitor provided with a second external electrode is characterized by having the following configuration.

That is, of the plurality of internal electrodes, the internal electrode extended to the first end face is formed to have a width exposed on both side faces of the dielectric ceramics connecting the first and second end faces, and on the other hand, It is characterized in that the internal electrode extended to the second end face is formed to have a width that leaves a side margin region between both side faces of the dielectric ceramic.

[Action]

Since the internal electrodes having a width narrower than that of the internal electrodes exposed on both sides of the dielectric ceramic are overlapped with each other through the dielectric ceramic layer, the opposing internal electrodes have both sides of the dielectric ceramic. Even if there is a slight deviation in the direction in which the surfaces are connected, the overlapping area does not change, and therefore the variation in capacitance can be reduced.

In addition, an internal electrode formed to have a width exposed on both side surfaces of the dielectric ceramic and an internal electrode formed to have a width that leaves the side margin region between both side surfaces of the dielectric ceramic are provided with a dielectric ceramic layer therebetween. Since they are overlapped with each other, a relatively large overlap area can be obtained,
The acquisition capacity can be increased.

Moreover, since only the internal electrodes connected to one of the potentials are exposed on the side surface, for example, when the laminated body is cut before sintering, the internal electrode forming conductive paste exposed on the side surface is cut. Even if it drips on the surface, it does not come into contact with the internal electrode conductive paste connected to the other potential. Therefore, since a short circuit is unlikely to occur, the thickness of the dielectric ceramic layer between the opposing internal electrodes can be reduced, which can also increase the acquisition capacitance.

[Explanation of Example]

FIG. 1 is an exploded perspective view for explaining a printed shape of a ceramic green sheet and a conductive paste used to obtain a multilayer capacitor according to an embodiment of the present invention. The ceramic green sheets 11 and 12 are prepared by forming a ceramic slurry mainly composed of a dielectric ceramic into a rectangular shape by a doctor blade method or the like.

Conductive pastes 13 and 14 for forming internal electrodes are printed on the upper surfaces of the ceramic green sheets 11 and 12, respectively, by a screen printing method or the like. The conductive paste 13 is
The ceramic green sheet 11 is printed from one end edge 11a to the other end edge 11b side, but so as not to reach the other end edge 11b.

The conductive paste 13 is a ceramic green sheet.
It is formed over the entire width of 11, that is, the width reaching the side edges 11c, 11d. The tip portion of the conductive paste 13, that is, the edge
In the portion on the 11b side, the side edges 11c, 11d are shaped to be farther from the end edge 11b than the central portion. This is to prevent the internal electrode based on the conductive paste 13 from being electrically connected to the external electrode on the other side when the external electrode described later is formed.

On the other hand, the conductive paste 14 is a ceramic green sheet.
Narrower than 12, i.e. side gap regions 15,15
Is formed so as to be provided between both side edges 12c and 12d of the ceramic green sheet 12.

In the multilayer capacitor of this example, the conductive paste 13,14
Multiple ceramic green sheets printed with 11 and 12
Are alternately laminated, and if necessary, a ceramic green sheet on which an electrically conductive paste is not printed is further laminated on the upper portion or the lower portion, thereby obtaining a laminated body.

Next, by sintering the laminated body, the sintered dielectric ceramics shown in FIG. 4 can be obtained. In the dielectric ceramics 16, the conductive pastes 13 and 14 (FIG. 1) are baked to form a plurality of internal electrodes 13 and 14 therein. In the present specification, the internal electrodes will be described by giving the same reference numerals to the above-mentioned internal electrode forming conductive pastes 13 and 14.

The plurality of internal electrodes 13 are drawn out to the first end surface 16a of the dielectric ceramic 16 and are also exposed at both side surfaces 16c and 16d. On the other hand, the plurality of internal electrodes 14 overlapping with the internal electrodes 13 are drawn out only to the second end surface 16b of the dielectric ceramics 16.

As shown in FIG.
By providing the first and second external electrodes 17a and 17b, the multilayer capacitor 18 can be obtained. First and second external electrodes
17a and 17b are formed to cover at least the first and second end surfaces 16a and 16b of the dielectric ceramic 16, respectively. In order to prevent the second external electrode 17b from short-circuiting with the internal electrode 13, the internal electrode 13 is connected to the external electrode 17b.
In the vicinity, it is not exposed on both side surfaces 16c, 16d of the dielectric ceramic 16.

In the multilayer capacitor 18 of the above embodiment, one internal electrode
13 is formed so as to extend to the entire width of the dielectric ceramics 16, and the other internal electrode 14 is formed so as to leave the side gap region 15, that is, narrower than the internal electrode 13, so that W in FIG. In the direction, even if there is slight misalignment of the conductive pastes 13 and 14 or misalignment of the ceramic green sheets 11 and 12, the internal electrodes 13 and 14
The overlapping area between them is kept constant. Therefore, it is possible to obtain a multilayer capacitor with a small variation in capacitance.

Not only that, in the conventional example of FIG. 2, when the laminated body was cut, the conductive paste might be short-circuited at the cut surface, but in the laminated capacitor of the present embodiment, the conductive paste exposed on the side surface of the laminated body. Is only the conductive paste 13 for forming the internal electrode connected to one potential. Therefore, the side surface of the conductive paste 13-ga laminated body (side surface 16c in FIG. 4,
Even if it hangs down on the surface corresponding to 16, there is no possibility of short-circuiting to the internal electrode 14 connected to the other potential, and the function as a capacitor is not hindered. Therefore, there is no possibility of a short circuit accident, and the thickness of the ceramic green sheets 11 and 12 in FIG. 1 can be reduced, which also increases the acquisition capacity.

The shape of the internal electrodes formed over the entire width of the dielectric ceramics is not limited to the shape of the conductive paste 13 shown in FIG. For example, as shown in FIG. 6 (a), a rectangular internal electrode 21 may be formed. The alternate long and short dash line A indicates the formation position of the external electrode.

Further, as shown in FIG. 6 (b), in order to more surely prevent the quadrangle from being connected to the external electrode on the other side, as in the conductive paste 13 shown in FIG. The shape may be such that the side surfaces 16c and 16d of 16 are receded. Further, as shown in FIG. 6 (c), an internal electrode 23 having a shape in which steps 23a and 23b are provided so as to recede on the side surfaces 16c and 16d side compared to the central region may be used.

It should be pointed out that the size T shown in the drawing of FIG. 1 is selected as an appropriate size depending on the size of the entire chip, the coating area of the external electrodes, the forming method, and the like.

In the multilayer capacitor 18 shown in FIG. 5, the first, second
When the external electrodes 17a, 17b of the above are formed by plating or the like, the plating film adheres to the side surfaces 16c, 16d of the dielectric ceramic 16 to a considerable extent, and the internal electrode 14 and the second external electrode 17 are formed.
There is a risk of short-circuiting with b. Therefore, in order to prevent such a short circuit, it is preferable that the external electrodes 17a and 17b are formed by a method such as a sputtering method that can be easily applied accurately to a predetermined region.

After sintering, the side surfaces 16c and 16d of the dielectric ceramic 16 shown in FIG. 4 may be coated with an insulating resin or the like. If the side surfaces 16c and 16d are provided with a coating layer, the above-mentioned short circuit accident can be prevented more reliably, so that any external electrode forming method can be used.

〔The invention's effect〕

As described above, in the present invention, the internal electrode connected to one potential is formed to have a width exposed on the side surface of the dielectric ceramic, and the internal electrode connected to the other potential has the side gap region as the side surface. Since it is formed with the width left between, in the direction connecting both sides of the dielectric ceramic,
Even if the positions where the internal electrodes are formed are slightly deviated, the overlapping area of the facing internal electrodes is always kept constant. Therefore, the capacitance of the multilayer capacitor can be kept constant.

Moreover, since only the internal electrode connected to one potential is exposed on the side surface of the dielectric ceramic, even if the conductive paste for forming an internal electrode drips on the side surface of the laminated body, the external electrode connected to the other potential side is formed. There is no danger of short-circuiting with. Therefore, since the thickness of the dielectric ceramic layer between the opposing internal electrodes can be reduced, a larger capacitance can be obtained as compared with the conventional multilayer capacitor shown in FIG.

[Brief description of drawings]

FIG. 1 is an exploded perspective view for explaining a printed shape of a ceramic green sheet and a conductive paste used to obtain a multilayer capacitor according to an embodiment of the present invention, and FIG. 2 is an example of a conventional multilayer capacitor. FIG. 3 is an exploded perspective view for explaining a printed shape of a ceramic green sheet and a conductive paste for carrying out the method, FIG. 3 is a schematic plan sectional view for explaining another example of the conventional multilayer capacitor, and FIG. 5 is a perspective view for explaining a dielectric ceramic and an internal electrode used in one embodiment of the present invention, FIG. 5 is a perspective view of a multilayer capacitor of one embodiment of the present invention, and FIGS. 6 (a) to 6 (c).
[Fig. 3] is a plan sectional view for explaining another example of the internal electrode shape. In the figure, 11,12 are ceramic green sheets, 13,14
Is an internal electrode (conductive paste for forming an internal electrode), 15 is a side gap region, 16 is dielectric ceramics, 16a and 16b are first and second end faces, 16c and 16d are side faces, and 17a and 17b are first and first sides. Reference numeral 2 denotes an external electrode, and 18 denotes a multilayer capacitor.

Claims (1)

[Claims] 1. A first and a second end surface facing each other, and a first and a second end.
And a dielectric ceramic having a side surface connecting the end surfaces of the dielectric ceramic and a ceramic layer disposed in the dielectric ceramic so as to overlap with each other, and the dielectric ceramic is alternately drawn out to the first and second end surfaces in the thickness direction. A plurality of internal electrodes, and first and second external electrodes formed on the first and second end faces, wherein a plurality of internal electrodes are drawn to the first end face. The internal electrode is formed to have a width exposed on both side surfaces of the dielectric ceramics, and the internal electrode extended to the second end surface has a side margin area between the both side surfaces of the dielectric ceramics. A multilayer capacitor, which is formed to have a width that leaves.