JPH0396205A - Laminated capacitor - Google Patents

Abstract

PURPOSE:To obtain a laminated capacitor having structure, in which the dispersion of electrostatic capacitance is reduced and acquired capacitance can be increased effectively, by forming an internal electrode connected at one potential in width exposed to the side face of dielectric ceramics and shaping an internal electrode connected at the other potential in width in which a side margin region is left between side faces. CONSTITUTION:In a laminated capacitor 18 having dielectric ceramics 16 having oppositely faced first and second end faces and side faces tying the first and second end faces, a plurality of internal electrodes 13, 14 arranged so as to be superposed through ceramic layers in the dielectric ceramics 16 and alternately led out to the first and second end faces in the thickness direction, and first and second external electrodes 17a, 17b formed onto the first and second end faces, the internal electrodes 13 led out to the first end face are shaped in width exposed to both side faces of the dielectric ceramics 16, and the internal electrodes 14 led out to the second end face are formed in width in which side margin regions are left between both side faces of the dielectric ceramics 16.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a multilayer capacitor, and particularly to a multilayer capacitor with an improved internal electrode shape. [Prior art] When manufacturing multilayer capacitors, a sintered body is produced by laminating multiple ceramic green sheets printed with conductive paste to form internal electrodes, crimping them in the thickness direction, and then burning them together. Create.

In this case, since the multilayer capacitor is quite small, misalignment inevitably occurs when printing the conductive paste and when laminating the ceramic green sheets. Therefore, various methods have been devised to reduce printing misalignment and lamination misalignment. FIG. 2 is a perspective view for explaining an example of a conventional method for manufacturing a multilayer capacitor. Ceramic green sheet 1
．． 2, conductive pastes 3 and 4 for forming internal electrodes are printed in the shape shown in the figure, respectively. That is,
The S'F4 pastes 3 and 4 are formed to have the same width as the ceramic green sheet 1.2, and are drawn out to different opposing end surfaces when the conductive paste 3 and the conductive paste 4 are laminated. It is printed as follows. Here, a multilayer capacitor is obtained by laminating and sintering a plurality of ceramic main green sheets 1.2 and applying external electrodes to the internal electrode lead-out end surfaces of the sintered body. In the above multilayer capacitor, it is possible to effectively reduce printing misalignment of the conductive paste and lamination misalignment of the ceramic green sheet 1.2. That is, normally, a conductive paste is applied onto a relatively large mother ceramic sheet, and the laminated body is cut after being laminated.
Individual laminates are obtained. Therefore, when obtaining an individual laminate in which the ceramic double green sheets 1 and 2 shown in FIG. Can be done. On the other hand, FIG. 3 is a plan sectional view for explaining another example of a conventionally used 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 one end surface 5a of the dielectric ceramic main body 5. Therefore, even if the printing position is slightly shifted in the W direction when printing the conductive paste for forming the internal electrode 6.7, the ceramic coated with the conductive paste for forming the internal electrode 6.7 Even if there is a slight deviation in the W direction when green sheets are stacked, the overlapping area between the internal electrodes 6 and 7 will not change due to such printing or stacking deviations. In other words, in this structure, while acknowledging that printing misalignment and lamination misalignment will occur, by making the width of the internal electrode connected to one potential relatively wide, capacitance due to printing misalignment and lamination misalignment is reduced. Variations are prevented. [Technical Problems to be Solved by the Invention] In the conventional multilayer capacitor described with reference to FIG. 2, when cutting out individual laminates from a mother laminate, a cutting blade cuts the conductive paste 3 for forming internal electrodes. 4 hangs down on the cut surface,
There was a risk of short circuiting between the opposing internal electrodes. Therefore,
Since the thickness of the dielectric ceramic layer between the internal electrodes, that is, the thickness of the ceramic green sheet 1.2, cannot be made very thin, it has been difficult to increase the acquisition capacity. In addition, in the multilayer capacitor shown in FIG. 3, although variations in capacitance can be reduced by making the overlapping area constant, Even narrower internal electrode 7
Since the two electrodes are overlapped, the overlapping area between the opposing internal electrodes is extremely small. Therefore, you can only obtain a capacitor with a small capacity for its size. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multilayer capacitor having a structure that has less variation in capacitance and can effectively increase acquisition capacitance. [Means for Solving the Technical Problems] The present invention provides first and second end faces facing each other, and ? 1. A plurality of internal electrodes are arranged in the dielectric ceramic having a side surface connecting the second end surface and drawn out alternately to the first and second end surfaces in the thickness direction. A multilayer capacitor in which first and second external electrodes are provided on a second end face is characterized by having the following structure. That is, among the plurality of internal electrodes, the internal electrode drawn out to the first end face is formed to have a width exposed on both sides of the dielectric ceramic main body connecting the first and second end faces,
On the other hand, the internal electrode drawn out to the second end face is formed to have a width that leaves a side margin region between the internal electrode and the bidirectional face of the dielectric ceramic. [Function] Since internal electrodes with a narrower width are overlapped with internal electrodes with a width exposed on both sides of the dielectric ceramic via a dielectric ceramic layer, the opposing internal electrodes are Even if there is some deviation in the direction connecting both sides of the dielectric ceramic ξ, the overlapping area will not change, and therefore variations in capacitance can be reduced. In addition, internal electrodes formed in a width that is exposed on both side surfaces of the dielectric ceramic ξ and internal electrodes formed in a width that leaves a side margin region between both side surfaces of the dielectric ceramic a Since they are overlapped via a thick layer, a relatively large overlapping area can be obtained and the acquisition capacity can be increased. Moreover, since only the internal electrodes connected to one potential are exposed on the side surfaces, even if the laminate is cut before sintering, the internal electrode shape or conductive paste exposed on the side surfaces may be damaged. Even if it drips on the cut surface, it will not come into contact with the conductive paste for internal electrodes connected to the other potential.
Therefore, since short circuits are less likely to occur, the thickness of the dielectric ceramic layer between the opposing inner electrodes can be made thinner, thereby increasing the acquisition capacity. [Description of Embodiments] FIG. 1 is an exploded perspective view for explaining the printed shapes of a ceramic green sheet and 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 shaping a ceramic slurry mainly composed of dielectric ceramic into a rectangular shape using a doctor blade method or the like. On the top surface of each ceramic green sea}11.12,
Internal electrode-type conductive pastes 13 and 14 are printed on each of them using a screen printing method or the like. The conductive paste 13 is applied to one edge 1 of the ceramic ξ
It is printed from 1a to the other edge 1lb side, but not to the other edge 1lb. In addition, the conductive paste 13 is made of ceramic and green sea.
11, that is, the width extends to the side edges 11c and 1ld. Note that the tip portion of the conductive paste 13, that is, the edge 11bf@ portion, is shaped such that the side edges 11c and the lid side portion are further away from the edge 1lb than the center 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 an external electrode, which will be described later, is formed. On the other hand, the conductive paste l4 has a width narrower than the ceramic green sheet l2, that is, the side gap region 15.
．． 15 with ceramic green sea} Both side edges 12c of 12
．． 12d. In the multilayer capacitor of this example, the conductive paste 13.1
A plurality of ceramic green sheets 11 with 4 printed on them
．． 12 are alternately laminated, and if necessary, a ceramic green sheet without printed conductive paste is further laminated on the top or bottom, thereby obtaining a laminate. Next, by sintering the laminate, the sintered dielectric ceramics shown in FIG. 4 can be obtained. For dielectric ceramic 16, conductive paste 13.14 (Fig. 1)
is baked, thereby forming a plurality of internal electrodes 13 and 14.
is formed inside it. Note that in this specification, the internal electrodes are formed using the above-mentioned conductive paste l for forming internal electrodes.
-13.It is explained by giving the same reference number as 14. The plurality of internal electrodes 13 are drawn out to the first end surface 16a of the dielectric ceramic ξ6, and are extended to both side surfaces 16c.
, 16d are also exposed. On the other hand, the plurality of internal electrodes l4 overlapping with the internal electrode l3 are made of dielectric ceramic l.
It is pulled out only to the second end surface 16b of 6. As shown in FIG. By providing the second external electrodes 17a and 17b, a multilayer capacitor 18 can be obtained. The first and second external electrodes 17a and 17b are the first and second external electrodes 17a and 17b of the dielectric ceramics 16, respectively. It is formed to cover at least the second end surfaces 16a and 16b. In order to prevent the second external electrode 17b from short-circuiting with the internal electrode 13, the internal electrode l3 is not exposed on both sides 16c and 16d of the dielectric ceramic cover 16 in the vicinity of the external electrode 17b. Not yet. In the multilayer capacitor l8 of the above embodiment, one internal electrode 13 is formed to have a width that extends to the entire width of the dielectric ceramic 16, and the other internal electrode 14 is formed in the side gap region 1.
5, that is, narrower than the internal electrode 13, in the W direction in FIG.
Even if there is a slight misalignment in printing 13 and 14 or a misalignment in the stacking of ceramic green sheets 11 and 12, the overlapping area between internal electrodes 13 and 14 remains constant. Therefore, a multilayer capacitor with less variation in capacitance can be obtained. In addition, in the conventional example shown in FIG. 2, there was a risk that the conductive paste would short-circuit at the cut surface when the laminate was cut.
In the multilayer capacitor of this example, the only conductive paste exposed on the side surface of the multilayer body is the conductive paste l3 for forming an internal electrode connected to one potential. Therefore,
The conductive paste l3 is applied to the side surface of the laminate (side surface 16c in Fig. 4).
．． 16), there is no risk of short-circuiting to the internal electrode 14 connected to the other potential, and the function as a capacitor is not inhibited. Therefore, there is no risk of short-circuit accidents, so the Ceramifuku Green Sea}1
Since the thickness of 1.12 can be made thinner, the acquisition capacity can also be increased thereby. Note that the shape of the internal electrode formed over the entire width of the dielectric ceramic is not limited to the shape of the conductive paste l3 shown in FIG. For example, as shown in FIG. 6(a), a rectangular internal electrode 2l may be formed. Note that the dashed-dotted line A indicates the formation position of the external electrode. In addition, as shown in FIG. 6(b), in order to more reliably prevent a short circuit with the external electrode on the other side, the dielectric ceramic l6 is used in the central region, similar to the conductive paste l3 in FIG. The shape may be such that the side surfaces 16c and 16d are set back. Furthermore, as shown in FIG. 6(c), the steps 23 are set back on the sides l6c and 16d compared to the central area.
An internal electric conductor 8ii23 having a shape provided with a and 23b may also be used. It should be noted that the dimension T shown in FIG. 1 is selected to be an appropriate size depending on the overall size of the chip, the coating area and shape of the external electrode, etc. In the multilayer capacitor l8 shown in FIG. When forming the second external electrodes 17a and 17b by plating or the like, the plating film is formed on the side surface 1 of the dielectric ceramic 16.
6c and 16d, and there is a risk that the internal electrode l4 and the second external electrode 17b may be short-circuited. Therefore, in order to prevent such a short circuit, the external electrodes 17a,
17b is preferably formed using a method such as a sputtering method that is easy to apply accurately to a predetermined area. Also, after sintering, on the sides ii 16c and 16d of the dielectric ceramic appliance 16 in FIG. It may be coated with insulating resin, etc. Side surface 16c. If a coating layer is provided on 16d, the above-mentioned short-circuit accident can be more reliably prevented, so any external electrode type method can be used. [Effects of the Invention] As described above, in the present invention, the internal electrode connected to one potential is formed with a width exposed to the side surface of the dielectric ceramic, and the internal electrode connected to the other potential is formed in the side gap. Even if the shape and position of the internal electrodes are slightly shifted in the direction connecting both sides of the dielectric ceramics, the opposing internal electrodes will not overlap. The area is always kept constant. Therefore,
The capacitance of a multilayer capacitor can be kept constant. Moreover, since only the internal electrode connected to one potential side is exposed on the side surface of the dielectric ceramic, even if the internal electrode type conductive paste drips on the side surface of the laminate, it will not be connected to the other potential side. There is no risk of short-circuiting with the external electrode. Therefore, since the thickness of the dielectric ceramic layer between the opposing internal electrodes can be made thinner, a larger capacitance can be obtained compared to the conventional multilayer capacitor shown in FIG.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view for explaining the printed shapes of a ceramic green sheet and 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 a schematic plan cross-sectional view for explaining another example of a conventional multilayer capacitor; FIG. The figure is a perspective view for explaining dielectric ceramics and internal electrodes used in one embodiment of the present invention, FIG. 5 is a perspective view of a multilayer capacitor in one embodiment of the present invention, and FIGS. c) is a plan sectional view for explaining other examples of internal electrode shapes. In the figure, 11.12 is a ceramic green sheet, 13.14 is an internal electrode (internal electrode type or conductive paste), 15 is a side gap region, 16 is a dielectric ceramic, 16a and 16b are first and second end faces, 16c and 16d are side faces, 17a. 17b indicates first and second external electrodes, and 18 indicates a multilayer capacitor.

Claims (1)

[Scope of Claims] A dielectric ceramic having first and second end surfaces facing each other and a side surface connecting the first and second end surfaces; and a plurality of internal electrodes drawn out alternately on the first and second end faces in the thickness direction, and first and second external electrodes formed on the first and second end faces. In the multilayer capacitor comprising an electrode, an internal electrode drawn out to the first end face among the plurality of internal electrodes is formed to have a width exposed to both side surfaces of the dielectric ceramic, and the internal electrode extends from the second end face. The internal electrode drawn out to the end face of the dielectric ceramic is formed to have a width that leaves a side margin area between the internal electrode and both side surfaces of the dielectric ceramic.
Multilayer capacitor.