JP2002299149A - Laminated ceramic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated ceramic capacitor whose capacitance can be increased, while an insulation defect is being prevented and whose cutting deviation or the like in the L direction can be detected easily. SOLUTION: Long sides of a dielectric layer on a third internal electrode 5 are formed, in such a way that they are brought close to short sides of the dielectric layer from their both end parts toward cental parts; formation positions of dummy electrodes 13, 14 are arranged to be separated in both end parts, in regions of the short sides of the dielectric layer corresponding to the short sides of the electrode 5; and the areas of the dummy electrodes 13, 14 are formed to become small as they enter the inside of the dielectric layer from their exposed parts.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electronic component such as a multilayer ceramic capacitor.

[0002]

2. Description of the Related Art A high withstand voltage multilayer ceramic capacitor has first and second internal electrodes connected to different external electrodes disposed so as to face each other via a dielectric layer constituting an element (chip). Among them, there is a type having a structure in which a third internal electrode not connected to an external electrode is provided (two-series structure) so that two capacitor portions connected in series are formed.

In the production of such a multilayer ceramic capacitor, a plurality of elements can be extracted and a first and a second internal electrode corresponding to each element region are formed on a large ceramic green sheet serving as a dielectric layer. (3) A conductor film to be an internal electrode is formed, a plurality of these large green sheets are laminated, and cut to a predetermined size according to an element region to form an unfired laminate. Thereafter, the unfired laminate was fired, and external electrodes connected to the first and second internal electrodes were formed on both end surfaces of the fired laminate.

However, in the above-described conventional manufacturing method, when the first and second internal electrodes, the third internal electrode, and the dielectric layer are laminated and pressed, the third internal electrode has a width of the laminated body. In some cases, the first and second internal electrodes do not overlap at a predetermined position.

[0005] For this reason, the error of the capacitance exceeds the specified value, and defective products are generated. Further, since the third internal electrode is not exposed on the end face of the laminated body, the above-mentioned positional deviation cannot be inspected from the cut end face.

Therefore, conventionally, the unfired laminate has been arbitrarily extracted and cut to check for print misregistration.

[0007] However, the multilayer ceramic capacitor is usually as small as a few mm square, and has a drawback that it is very difficult to cut and difficult to inspect. In addition, there is a problem that a laminated ceramic capacitor cut for inspection cannot be commercialized.

In order to achieve the above object, as shown in FIG. 4, the third internal electrode 45 is formed on the same layer as the third internal electrode 45.
No. 27660 discloses a multilayer ceramic capacitor 40 in which dummy electrodes 53 and 54 for position confirmation exposed at the end faces corresponding to the positions are arranged at a distance from the third internal electrode 45.
No. 85 discloses this.

According to the report, the first and second internal electrodes 43,
After laminating 44, the third internal electrode 45, the dummy electrodes 53 and 54, and the dielectric layer 42 and pressing them in the layer direction, if the position of the third internal electrode 45 shifts, The dummy electrodes 53 and 54 are shifted. Therefore, by visually recognizing the dummy electrodes 53 and 54 exposed on the end surfaces, the third electrodes
The position of the internal electrode 45 can be known.

[0010]

However, according to the multilayer ceramic capacitor, it is necessary to increase the distance between the third internal electrode 45 and the dummy electrodes 53 and 54 to some extent in order to prevent insulation failure. Therefore, there is a problem that the overlapping area between the first and second internal electrodes 53 and 54 and the third internal electrode 45 is reduced, and the acquisition capacity is reduced.

In addition, even if the printing deviation and the cutting deviation in the longitudinal direction (hereinafter, L direction: the end direction where the pair of external electrodes are formed) are shifted, the first and second deviations appear from the cut surface.
Since the width of the conductor film serving as the internal electrode is the same, inspection cannot be performed from the cut end face.

Here, if a method of printing the internal electrodes of the even-numbered layers by printing the internal electrodes of the even-numbered layers by using one plate making and printing the internal electrodes of the odd-numbered layers by shifting the plate making in the W direction is used, the printing deviation in the L-direction is almost eliminated. Does not occur. However, the cutting displacement in the L direction occurs with the same probability as the cutting displacement in the width direction (hereinafter, W direction: the end direction where no external terminal electrode is formed).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to make it possible to increase the capacity while preventing insulation failure and to easily detect a displacement in the L direction. It is an object of the present invention to provide a monolithic ceramic capacitor that can achieve the above.

[0014]

According to the present invention, there is provided a multilayer ceramic capacitor comprising: a laminated body in which a plurality of rectangular dielectric layers are laminated; A first internal electrode group formed with a first internal electrode extended to the first internal electrode and a second internal electrode extended to the other short side from the other short side of the dielectric layer without being connected to the first internal electrode. A third internal electrode facing both of the first and second internal electrodes via a dielectric layer on a plane of the dielectric layer different from the dielectric layer, and both short sides of the dielectric layer And a second internal electrode group formed with a dummy electrode for confirming misalignment that is exposed from the third internal electrode and is not connected to the third internal electrode. The side is closer to the short side of the dielectric layer from both ends to the center. It was formed to protrude memorial,
The formation position of the dummy electrode is such that two dummy electrodes are separately arranged on both ends of a region of the dielectric layer short side opposed to the dielectric layer short side of the third internal electrode. The area of the dummy electrode is formed so as to decrease as the area from the short side of the dielectric layer to the inside of the dielectric layer.

According to the present invention, it is possible to increase the area of the third internal electrode as much as the area of the dummy electrode decreases as it goes inside while securing a margin between the third internal electrode and the dummy electrode. That is, by securing the above margin, while preventing insulation failure, the overlapping area of the first and second internal electrodes and the third internal electrode is widened, whereby the miniaturization and high capacity of the multilayer ceramic capacitor can be realized.

In addition, when the cutting displacement in the L direction occurs, the width of the electrode cutout portion of the dummy electrode exposed on the end surface changes, and if the appearance is inspected, a cutting displacement in the length direction of the ceramic body is found. can do. Therefore, the inspection work and the image recognition for inspecting the cutting deviation are simple, and the inspection efficiency can be improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A multilayer ceramic capacitor according to the present invention will be described below with reference to the drawings.

FIG. 1 is an external perspective view of a multilayer ceramic capacitor according to the present invention. FIG. 2 is a (a) cross-sectional view and (b) a plan view of the multilayer ceramic capacitor of the present invention.

In the figure, 10 is a multilayer ceramic capacitor, 1 is a laminated body, 2 is a dielectric layer, 3, 4 are first and second layers.
Internal electrodes, 5 is a third internal electrode, 7, 8 are external electrodes, 1
Numerals 3 and 14 are dummy electrodes for position confirmation. 1st, 2nd
The internal electrodes 3 and 4 form a first internal electrode group. The third internal electrode and the dummy electrodes 13 and 14 are
An internal electrode group is formed.

The first internal electrode 3 is led out to one end of the laminate body 1 in the L direction, and the second internal electrode 4 is led out to the other end. Further, the first internal electrode 3 and the second internal electrode 4 are arranged in the same layer as a pair, and the first internal electrode 3 and the second internal electrode 4 Insulated by layer 2. The third internal electrode 5 and the dummy electrodes 13 and 14 are arranged in the same layer, and are stacked on the first and second internal electrodes 3 and 4 with the dielectric layer 2 interposed therebetween.
Further, the third internal electrode 5 is disposed at the center of the multilayer body 1 so as not to be exposed on the end surface of the multilayer body 1, and one end in the L direction overlaps the first internal electrode 3 and the other end. Are arranged so as to overlap the second internal electrode 4. The dummy electrodes 13 and 14 are insulated from the third internal electrode 5, and the L of the third internal electrode 5 is exposed so as to be exposed on the end surface of the multilayer body 1.
It is arranged on each side of the direction.

Here, the short side of the dielectric layer 2 of the third internal electrode 5 is formed so as to protrude from both end portions to the central portion so as to approach the short side of the dielectric layer 2, and the dummy electrode 1 is formed.
The formation positions of the third and the inner electrodes 5 are separated from each other at both ends of the region of the short side of the dielectric layer 2 corresponding to the short side of the third internal electrode 5, and the area of the dummy electrodes 13 and 14 is It is formed so as to become smaller as it enters the inside of the dielectric layer 2.

Moreover, the dummy electrodes 13 and 14 are formed in a triangular shape, and are arranged so as to be concave at the oblique sides of the dummy electrodes 13 and 14 separated in the short side direction of the dielectric layer 2.
The short side of the dielectric layer 2 of the third internal electrode 5 protrudes toward the concave inside. The capacitance can be increased by arranging the oblique sides of the dummy electrodes 13 and 14 so that the curves of the protruding portions of the third internal electrodes 5 are substantially parallel to each other.

Further, external electrodes 7 and 8 which are connected to the first and second internal electrodes 3 and 4 are formed at both ends of the multilayer body 1, and connected to an external circuit via the external electrodes 7 and 8. I can do it. The dummy electrodes 13 and 14 are also connected to the external electrodes 7 and 8.

The above-described multilayer ceramic capacitor 10 is manufactured as follows. Note that, in the description, a green sheet serving as a dielectric layer, a conductor film serving as an internal electrode, and a laminated body are denoted by reference numerals before firing treatment for convenience.

First, a large ceramic green sheet from which a plurality of elements can be extracted and which becomes the dielectric layer 2 is prepared. Specifically, a slurry of a dielectric ceramic material is formed to a predetermined thickness by a doctor blade method or the like.

Next, a conductor film to be the first and second internal electrodes 3 and 4 is formed on each element region of the large green sheet by using Ag,
Using a conductive paste made of Pd, a base metal, or the like, printing is performed by a screen printing method or the like.

Similarly, a conductive film to be the third internal electrode 5 and the dummy electrodes 13 and 14 is formed in each element region of the large green sheet using a conductive paste.

Here, a convex portion is formed on the third internal electrode 5, and concave portions (electrode cutout portions) 23, 24 having substantially the same shape as the convex portion of the third internal electrode 5 are formed on the dummy electrodes 13, 14. The non-electrode region to be formed is formed by plate-making control of screen printing.

As described above, the green sheet serving as the dielectric layer on which the conductor films serving as the first and second internal electrodes 3 and 4 are formed, and the conductor film serving as the third internal electrode 5 and the dummy electrodes 13 and 14 are formed. The formed green sheets are alternately laminated, and if necessary, ceramic green sheets having no conductive film formed on the upper or lower part are further laminated and integrated by pressure bonding.

Next, the large-sized laminate in which the predetermined green sheets are laminated is cut into a predetermined size in accordance with each element region to form the unfired laminate 1.

Next, the dummy electrodes 13 and 14 on the end surfaces of the laminate 1 obtained by cutting the large laminate described above in accordance with a predetermined element region.
The state of exposure of the electrode notch 7 is visually confirmed, and a cutting deviation is confirmed. Here, the laminated body 1 that can be determined as a cutting shift is removed from the manufacturing process.

When the cutting is performed at a correct position, the width of the exposed portion of the dummy electrode 13 on one cut end surface of the laminate 1 is as shown in FIG.

On the other hand, when a cutting displacement in the W direction occurs,
As shown in FIG. 3B, the position of the exposed portion of the dummy electrode 13 changes.

When a cutting displacement in the L direction occurs,
The width of the exposed portion of the dummy electrode 13 changes as shown in FIG.

Also, when a printing shift or a stacking shift occurs in the L or W direction, the position of the exposed portion of the dummy electrode 13 similarly changes.

Therefore, it can be easily determined from the width of the exposed portion of the dummy electrode 13 whether or not the capacitance of the capacitor is within the specified range. If a defective product is found, the operation should be interrupted here. Can be. Thereby, waste of time and labor can be reduced as compared with the related art.

Next, the uncut fired laminate 1 that has been cut correctly is fired at a predetermined atmosphere and a predetermined temperature. As a result, the first and second internal electrodes 3, between the dielectric layers 2,
4, a laminate 1 in which the third internal electrode 5 and the dummy electrodes 13 and 14 are arranged.

Next, the end faces of the laminate 1 are polished so that the first and second internal electrodes 3 and 4 are exposed from the end faces of the laminate 1 over the entire width thereof, and include the pair of end faces. External electrodes 7 and 8 are formed at the ends. Specifically, Ag, C
u, Ni or other thick film conductive paste is baked to form a base conductor film, and Ni plating, Sn plating,
Au plating or the like is applied. Thus, the multilayer ceramic capacitor 10 shown in FIG. 1 can be obtained.

Thus, according to the multilayer ceramic capacitor 10 of the present invention, the short side of the dielectric layer 2 of the third internal electrode 5 protrudes from both ends to the center so as to approach the short side of the dielectric layer 2. The position of the dummy electrodes 13 and 14 for position confirmation is divided into a plurality of dummy electrodes 13 and 14 at both ends of the region of the short side of the dielectric layer 2 corresponding to the short side of the third internal electrode 5. And the dummy electrodes 13 and 14 are formed so that the area of each of the dummy electrodes 13 and 14 becomes smaller as it enters the dielectric layer 2 from the exposed portion. The area of the third internal electrode 5 can be increased by the reduced area of the dummy electrodes 13 and 14 while securing a margin.
That is, by securing the margin, while preventing insulation failure, the overlapping area of the first and second internal electrodes 3 and 4 and the third internal electrode 5 is increased, so that the multilayer ceramic capacitor 10 is reduced in size and increased in capacitance. Can be realized.

Further, when a cutting shift occurs in the L direction, the electrode cutouts 23, 2 of the dummy electrodes 13, 14 exposed on the end surfaces are formed.
Since the width of 4 changes, it is possible to find out the cutting displacement of the ceramic body in the L direction by inspecting the appearance. Therefore, the inspection work and the image recognition for inspecting the cutting deviation are simple, and the inspection efficiency can be improved.

When the margin is reduced for the purpose of miniaturization and high capacity, the third internal electrode 5 and the dummy electrodes 13, 1
There is a problem that poor adhesion of the green sheet sandwiching No. 4 occurs. That is, the adhesion between different types of materials is inferior to the adhesion between green sheets serving as dielectric layers. Here, in the present invention, when the margins are set to be the same, the area between the third internal electrode 5 and the dummy electrodes 13 and 14 is increased, so that there is also an effect that poor adhesion can be reduced.

Further, the third internal electrode 5 and the dummy electrode 13,
By using the same material for the 14, the third internal electrode 5 and the dummy electrodes 13 and 14 can be formed at the same time, so that it can be easily implemented without making a significant change in the manufacturing process, and the cost can be reduced. Does not lead to a rise.

In this embodiment, the present invention is applied to a ceramic capacitor. However, the present invention is not limited to this. For example, the present invention can be applied to the manufacture of a laminated body such as a piezoelectric actuator and a laminated inductor.

In this embodiment, the dummy electrodes 13 and 14 are arranged on both sides of the third internal electrode 5, but the same effect can be obtained by using only one of them.

The shape of the concave portion of the dummy electrode and the shape of the convex portion of the third internal electrode may be any shape such as a curved shape. What is important is that a margin can be secured.

Also, a misregistration detection mark or the like may be provided on the layer on which the first and second internal electrodes 3 and 4 are formed.

[0046]

According to the present invention, the short side of the dielectric layer of the third internal electrode is formed so as to protrude from both ends to the center and approach the short side of the dielectric layer. A plurality of dummy electrodes are separately arranged at both ends of a region of the dielectric layer short side corresponding to the short sides of the first and second internal electrodes, and the area of the dummy electrode is Since it is formed so as to become smaller as it enters the dielectric layer from the exposed portion, a margin between the third internal electrode and the dummy electrode is secured while the area of the dummy electrode is reduced by the reduced area of the third internal electrode. The area can be expanded.

That is, by securing the above margin, the overlap area between the first and second internal electrodes and the third internal electrode is widened while preventing insulation failure, thereby realizing the miniaturization and high capacity of the multilayer ceramic capacitor. it can.

Further, when the cutting displacement in the L direction occurs, the width of the electrode cutout portion of the dummy electrode exposed on the end face changes, and if the appearance is inspected, the cutting displacement in the longitudinal direction of the ceramic body is found. can do. Therefore, the inspection work and the image recognition for inspecting the cutting deviation are simple, and the inspection efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a multilayer ceramic capacitor according to the present invention.

2A is a cross-sectional view of the multilayer ceramic capacitor of the present invention, and FIG. 2B is a plan view.

3A and 3B are diagrams illustrating a state of an end face of the multilayer ceramic capacitor of FIG. 2 at the time of cutting displacement, wherein FIG.
(B) shows a case in which it is shifted in the W direction, and (c) shows a case in which it is shifted in the L direction.

FIG. 4 is a cross-sectional view of a conventional multilayer ceramic capacitor (a), and FIG. 4 (b) is a plan view.

[Explanation of symbols]

10, 40 multilayer ceramic capacitor 1 multilayer body 2, dielectric layer 3, 4, first and second internal electrodes (first internal electrode group) 5, third internal electrode (second internal electrode group) 7, 8 external electrode 13 , 14 dummy electrode (second internal electrode group) 23, 24 recess

Claims (1)

[Claims] A stacked body in which a plurality of rectangular dielectric layers are stacked; a first internal electrode extending from one short side to the other short side on the same plane of the dielectric layer; A first internal electrode group formed with a second internal electrode that is not connected to the first internal electrode but is drawn out from the other short side of the dielectric layer to one short side, and a dielectric layer different from the dielectric layer The first,
A third internal electrode that faces both of the second internal electrodes via a dielectric layer, and a dummy electrode that is exposed from both short sides of the dielectric layer and that is not connected to the third internal electrode, and that is used to confirm a displacement. Wherein the short side of the dielectric layer of the third internal electrode is closer to the short side of the dielectric layer from both ends to the center of the multilayer ceramic capacitor. The two dummy electrodes are separated at both ends of a region of the dielectric layer short side opposite to the dielectric layer short side of the third internal electrode. And the area of each of the dummy electrodes is formed so that the area of each of the dummy electrodes decreases from the short side of the dielectric layer to the inside of the dielectric layer.