JP2005285995A - Surface mount type multiple capacitors - Google Patents

Abstract

Even when the interval between adjacent capacitor elements is narrowed to reduce the size of the entire structure, it is possible to effectively prevent a short circuit between solders attached to a terminal electrode and to have excellent mountability. A surface mount type multiple capacitor is provided.
A plurality of dielectric layers are stacked to form a rectangular parallelepiped stacked body, and a plurality of internal electrodes are interposed between adjacent dielectric layers inside the stacked body. A plurality of capacitor elements (n is a natural number of 2 or more) are arranged in a row in the stacking direction of the dielectric layers, and terminal electrodes provided corresponding to the capacitor elements are attached to the side surfaces of the stack. In the surface mount type multiple capacitor, the terminal electrode is commonly connected to the outer peripheral portion of the internal electrode located in the central area of the capacitor element in the vicinity of the mounting surface of the multilayer body, and is positioned in the central area of each capacitor element. The internal electrodes that are positioned at the both end regions are electrically connected to each other by a connecting conductor that is attached to the side surface of the multilayer body with a predetermined gap between the internal electrodes.
[Selection] Figure 1

Description

  The present invention relates to a surface-mounted multiple capacitor that is surface-mounted on an external wiring board such as a mother board and is incorporated into various electronic devices such as a mobile phone.

  2. Description of the Related Art Conventionally, surface mount multiple capacitors each having a plurality of capacitor elements have been used as electronic components incorporated into various electronic devices.

  As such a conventional multiple capacitor, for example, the one shown in FIG. 5 is known. FIG. 5A is an external perspective view of a conventional multiple capacitor, and FIG. 5B is an exploded perspective view thereof. In the conventional multiple capacitor shown in the figure, a plurality of capacitor elements 24a, 24b, and 24c are disposed in a laminated body 21 in which a large number of dielectric layers 22 made of barium titanate or the like are laminated. In addition, the laminated body 21 has a structure in which a pair of terminal electrodes 25 corresponding to the capacitor elements 24a, 24b, and 24c are attached to the side surface (see, for example, Patent Document 1).

  The capacitor elements 24a, 24b, 24c are composed of a plurality of dielectric layers 22 and internal electrodes 23a, 23b, 23c interposed between the dielectric layers 22-22. On the lower surface and side surfaces of the multilayer body 21, each capacitor element is electrically connected to one of a corresponding pair of terminal electrodes 25.

  In such a conventional multiple capacitor, a predetermined voltage is applied between the internal electrodes of the capacitor elements 24a, 24b, and 24c via the pair of terminal electrodes 25, and is arranged between the internal electrodes of the capacitor elements 24a, 24b, and 24c. By forming a predetermined capacitance in the dielectric layer 22 that is formed, it functions as a multiple capacitor.

The conventional multiple capacitors described above are surface-mounted on an external wiring board such as a mother board by known soldering or the like. Specifically, after placing the above-described multiple capacitor on the external wiring board such that cream solder or the like is interposed between the terminal electrode 25 and the corresponding connection pad of the external wiring board, the claim The multiple capacitors are mounted by heating and melting the solder at a high temperature and soldering the terminal electrodes 25 of the multiple capacitors to the connection pads of the external wiring board.
Japanese Patent Laid-Open No. 11-16778

  However, in the conventional multiple capacitor described above, all the internal electrodes of each capacitor element are electrically connected to the corresponding terminal electrodes on the lower surface, side surface, etc. of the multilayer body. When the interval is reduced to reduce the size of the entire structure, the interval between adjacent terminal electrodes is also reduced. In that case, when multiple capacitors are mounted on an external electric circuit such as a mother board by soldering, the solder joining the terminal electrode and the connection pad of the external wiring board may contact the adjacent solder and cause a short circuit. There is a drawback that leads to mounting defects.

  The present invention has been devised in view of the above-described drawbacks, and the object of the present invention is to provide solder adhered to the terminal electrode even when the interval between adjacent capacitor elements is narrowed to reduce the overall structure. An object of the present invention is to provide a surface mount type multiple capacitor excellent in mountability, which can effectively prevent a short circuit between them.

  The surface mount type multiple capacitor according to the present invention forms a rectangular parallelepiped laminate by laminating a large number of dielectric layers, and includes a plurality of internal electrodes 1 between adjacent dielectric layers within the laminate. Terminals provided corresponding to each capacitor element on the side surface of the multilayer body in which n (n is a natural number of 2 or more) capacitor elements are arranged in a line in the direction of the dielectric layer lamination. In the surface-mounted multiple capacitor formed by attaching electrodes, the terminal electrode is commonly connected to the outer peripheral portion of the internal electrode located in the central region of the capacitor element in the vicinity of the mounting surface of the multilayer body, and An internal electrode located in the center area of the capacitor element and an internal electrode located in both end areas are electrically connected by a connecting conductor attached to the side surface of the multilayer body with a predetermined gap between the terminal electrodes. Be connected It is an feature.

  The surface mount type multiple capacitor according to the present invention is characterized in that the terminal electrode and the connecting conductor are made of an electroless plating film deposited on the surface of the multilayer body starting from the outer peripheral portion of each internal electrode. It is what.

  Furthermore, the surface mount type multiple capacitor according to the present invention is characterized in that the connecting conductors of adjacent capacitor elements are arranged so as to be shifted in a direction orthogonal to the arrangement direction of the capacitor elements.

  According to the surface mount type multiple capacitor of the present invention, the terminal electrode is connected to the outer peripheral portion of the internal electrode located in the central area of the capacitor element in the vicinity of the mounting surface of the multilayer body, and the internal located in the central area of the capacitor element. Since the electrode and the internal electrode located at both end regions are electrically connected by the connecting conductor attached to the side surface of the multilayer body with a predetermined gap between the terminal electrode, the adjacent capacitor elements are connected. Even in the case where the overall structure is reduced in size by narrowing the gap, a wide gap corresponding to both end regions of each capacitor element can be secured between the adjacent terminal electrodes. Therefore, when a surface mount type multiple capacitor is mounted on an external electric circuit such as a mother board by soldering, a short circuit occurs due to the contact of the solder joining the terminal electrode and the connection pad of the external wiring board with the adjacent solder. Is effectively prevented.

  Moreover, since a predetermined gap is provided between the connecting conductor and the terminal electrode, the solder can be applied to the connecting conductor even when molten solder crawls up along the terminal electrode when mounted on the external electric circuit. And the connection conductors adjacent to each other are hardly short-circuited via solder.

  Further, according to the surface mount type multiple capacitor of the present invention, the terminal electrode and the connecting conductor on the surface of the multilayer body are formed of an electroless plating film deposited on the surface of the multilayer body starting from the outer peripheral portion of each internal electrode. Thus, the terminal electrode and the connecting conductor can be formed by a simple process of immersing the laminate in which the outer peripheral portion of the internal electrode is partially exposed in a plating solution for electroless plating for a predetermined time. In addition, it is possible to improve the productivity of surface mount type multiple capacitors.

  Furthermore, according to the surface mount type multiple capacitor of the present invention, the connection conductors of adjacent capacitor elements are shifted in the direction orthogonal to the arrangement direction of the capacitor elements, so that when mounting on an external electric circuit, Even if the melted solder crawls up from the terminal electrode to the connecting conductor beyond the interval portion, it is possible to effectively prevent the adjacent connecting conductors from being short-circuited via the solder.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

  1 is an external perspective view of a surface-mounted multiple capacitor according to an embodiment of the present invention, FIG. 2A is a cross-sectional view of the surface-mounted multiple capacitor of FIG. 1, taken along line AA, and FIG. 1 is a cross-sectional view of the surface mount multi-capacitor of FIG. 1 taken along the line BB, FIG. 3 is an exploded perspective view of the surface mount multi-capacitor of FIG. 1, and the surface mount multi-capacitor shown in FIG. A pair of terminal electrodes having the upper end and the lower end extending to the mounting surface and the upper surface of the multilayer body 1 on the side surface of the multilayer body 1 having n capacitor elements 4a, 4b, and 4c (n is a natural number of 2 or more). 5a, 5b, and 5c are attached and formed corresponding to the capacitor elements 4a, 4b, and 4c. In the present embodiment, an example in which the number n of capacitor elements is set to “3” will be described.

  The multilayer body 1 is formed by laminating a large number of dielectric layers 2, and n capacitor elements 4a, 4b, 4c are arranged in a line in the laminating direction of the dielectric layers 2, and these capacitor elements Internal electrodes 3a and 3b are interposed between adjacent dielectric layers in the formation regions of 4a, 4b and 4c.

  The dielectric layer 2 is formed to a thickness of 1 μm to 3 μm per layer by a dielectric material mainly composed of, for example, barium titanate, calcium titanate, strontium titanate, and the like. The stacked body 1 is formed by stacking, for example, 20 to 2000 layers in a direction parallel to the mounting surface of the surface-mounted multiple capacitor. FIGS. 1 to 3 show a case where the number of stacked dielectric layers 2 is 42 in order to simplify the surface-mounted multiple capacitor of this embodiment.

  For example, when the dielectric layer 2 is made of a dielectric material mainly composed of barium titanate, an appropriate organic solvent, glass frit, organic binder, or the like is added to and mixed with the barium titanate powder. This is formed into a ceramic green sheet having a predetermined shape and thickness by a conventionally known doctor blade method or the like, and then the obtained ceramic green sheet is predetermined by a conventionally known green sheet laminating method or the like. A laminated body made of ceramic green sheets is formed by laminating and press-bonding the same number of sheets, and finally the laminated body is manufactured by firing at a temperature of 1100 ° C. to 1400 ° C., for example.

  On the other hand, a large number of internal electrodes 3a, 3b disposed in the formation regions of the capacitor elements 4a, 4b, 4c are alternately disposed with the dielectric layer 2 therebetween in the multilayer body 1. The first internal electrode 3a and the second internal electrode 3b are configured so that the first internal electrode 3a and the second internal electrode 3b adjacent to each other partially face each other with the dielectric layer 2 therebetween. Therefore, when a voltage is applied between the first internal electrode 3a and the second internal electrode 3b, a predetermined capacitance is generated in a region opposite to the first internal electrode 3a and the second internal electrode 3b. .

Among the internal electrodes 3 a and 3 b, the plurality of first internal electrodes 3 a arranged in the central area of the capacitor elements 4 a, 4 b and 4 c have a part of the outer periphery extending to the side surface of the multilayer body 1. In addition to being extended, it is commonly connected to one of the terminal electrodes 5a, 5b, 5c at a portion including at least the vicinity of the mounting surface (the lower surface in the drawing) of the multilayer body 1, and in the central region of each capacitor element 4a, 4b, 4c. The plurality of second internal electrodes 3 b arranged also extend to the side surface of the multilayer body 1 at a part of the outer periphery, and at the part including at least the vicinity of the mounting surface of the multilayer body 1, Commonly connected to 5b and 5c.

On the other hand, the capacitor element 4a, 4b, the internal electrodes 3 a, 3 b which is located 3 a, 3 b and both ends internal electrodes located in the center region of 4c, the terminal electrodes 5a, 5b, between 5c They are electrically connected by connecting conductors 6a, 6b, 6c that are attached to the side surfaces of the laminate 1 with a predetermined interval. All the first internal electrodes 3a provided in the capacitor elements 4a, 4b and 4c are connected to one of the connecting conductors 6a, 6b and 6c, and all the second internal electrodes 3b are connected to the other connecting conductors 6a, 6b and 6c. Commonly connected to

  Here, the “central area” and “both end areas” of the capacitor elements 4a, 4b, and 4c are expressions used for convenience to divide the capacitor elements 4a, 4b, and 4c into three areas. It is not determined by the dimensions from the above, the ratio in the whole, etc., but can be appropriately determined in the formation region of each capacitor element 4a, 4b, 4c. That is, if it is a region located slightly inside both ends of each capacitor element 4a, 4b, 4c, this region can be called a central region, and both regions are both end regions.

  The internal electrodes 3a and 3b are formed of a conductive material mainly composed of a metal such as nickel, copper, nickel / copper, silver / palladium or the like to a thickness of, for example, 0.5 μm to 8.0 μm. A conductive paste obtained by adding and mixing a suitable organic solvent, glass frit, organic binder, etc. to the above-mentioned metal material powder on the main surface of the ceramic green sheet used for forming 1 is conventionally known by screen printing or the like. It is formed by applying in a predetermined pattern or by depositing and transferring a plating film of a predetermined pattern.

  On the other hand, the terminal electrodes 5a, 5b, and 5c attached to the side surfaces of the multilayer body 1 are soldered to the connection pads of the external wiring board when the surface mount type multiple capacitors are mounted on the external wiring board such as a mother board. It functions as a terminal for external connection that is electrically connected via, for example, and is deposited and formed from the mounting surface of the laminate 1 to the upper surface via the side surface.

  Here, the terminal electrodes 5a, 5b, 5c are formed from the mounting surface of the multilayer body 1 to the upper surface through the side surface when the surface mount type multiple capacitor is mounted on an external wiring substrate such as a mother board. This is because the mounting operation can be performed without considering the vertical direction.

  Further, in the present embodiment, since the terminal electrodes 5a, 5b, and 5c are separated into two on the side surface of the multilayer body 1, the amount of solder rising when mounting is reduced, and the terminal electrode is pulled by the solder. The stress does not cause a large difference between one terminal electrode and the other terminal electrode. Therefore, the so-called “chip standing” phenomenon in which the solder that rises on one terminal electrode is torn and only the other terminal electrode is connected to the connection pad of the external wiring board is less likely to occur. The terminal electrodes 5a, 5b, and 5c are preferably set so that the height from the mounting surface is about one third of the height of the multilayer body 1.

  These terminal electrodes 5a, 5b, 5c, and connecting conductors 6a, 6b, 6c are, for example, conventionally known electroless plating methods. Specifically, the outer periphery of each internal electrode 3a, 3b is started on the surface of the laminate 1. As described above, the metal is deposited and these precipitates are connected to each other. In this case, the terminal electrodes 5a, 5b, and 5b are simply processed by simply immersing the laminate 1 in which the outer peripheral portions of the internal electrodes 3a and 3b are partially exposed in a plating solution for electroless plating for a predetermined time. 5c can be formed in a desired pattern, and can be used for improving the productivity of the surface mount type multiple capacitor.

  When the terminal electrodes 5a, 5b, 5c and the connecting conductors 6a, 6b, 6c are formed by the electroless plating method, the cross section thereof has a shape as shown in FIG. Further, in the case of forming by electroless plating, in order to connect the precipitates to each other, the shorter the interval between the internal electrodes 3a and 3b, the easier the formation. When the internal electrodes are alternately arranged for each dielectric layer as in this embodiment, the interval between the internal electrodes to be connected corresponds to two dielectric layers, so the thickness of the dielectric layer 2 is It is preferable to set it to 8 μm or less.

  Thus, the surface mount type multiple capacitor described above is configured such that a plurality of capacitor elements are mounted on an external wiring board such as a mother board by a single mounting by conventionally known soldering or the like, and each capacitor element 4a, A predetermined voltage is applied through a pair of terminal electrodes 5a, 5b, and 5c corresponding to 4b and 4c to form a plurality of capacitances, thereby functioning as a surface mount type multiple capacitor.

  According to the surface mount type multiple capacitor of the present embodiment, the terminal electrodes 5a, 5b, 5c are mounted on the outer periphery of the internal electrodes 3a, 3b located in the central area of the capacitor elements 4a, 4b, 4c. The laminated body is connected in the vicinity of the surface, and the internal electrodes located in the central area of the capacitor elements 4a, 4b, and 4c and the internal electrodes 3a and 3b located in both end areas are spaced apart from each other by a predetermined distance Since the connection conductors 6a, 6b, and 6c that are attached to the side surfaces of the first electrode are electrically connected to each other, the distance between adjacent capacitor elements is reduced to reduce the overall structure. A wide space corresponding to both end regions of each capacitor element can be secured between the terminal electrodes. Therefore, when a surface mount type multiple capacitor is mounted on an external electric circuit such as a mother board by soldering, a short circuit occurs due to the contact of the solder joining the terminal electrode and the connection pad of the external wiring board with the adjacent solder. Is effectively prevented.

  In addition, since a predetermined gap is provided between the connecting conductors 6a, 6b, 6c and the terminal electrodes 5a, 5b, 5c, the molten solder can connect the terminal electrodes 5a, 5b, 5c when mounted on the external electric circuit. Even if it goes up, it is less likely that solder will be applied to the connecting conductors 6a, 6b, 6c, and there is almost no possibility that adjacent connecting conductors will be short-circuited via the solder.

  Further, according to another embodiment, the surface mount type multiple capacitors as shown in FIG. 4 are arranged such that the connecting conductors 16a, 16b, and 16c of adjacent capacitor elements are shifted in a direction orthogonal to the arrangement direction of the capacitor elements. By so doing, even when the solder that has been melted rises from the terminal electrodes 15a, 15b, and 15c to the connecting conductors 16a, 16b, and 16c across the gap when mounted on the external electric circuit, it is adjacent. It is possible to effectively prevent the connecting conductors 16a, 16b, and 16c from being short-circuited via the solder.

  The present invention is not limited to the above-described embodiments, and various changes and improvements can be made without departing from the scope of the present invention.

  For example, in the above-described embodiment, the dielectric material forming the dielectric layer 2 may be added and mixed in the internal electrodes 3a and 3b.

  In the above-described embodiment, the terminal electrode is formed of the electroless plating film. However, instead of this, the terminal electrode may be formed by applying a conductive paste or the like.

  Further, in the embodiment described above, an example in which the number n of capacitor elements provided in the multilayer body 1 is set to “3” has been described. However, if the number n of capacitor elements is a natural number of 2 or more, Any number is acceptable.

  Furthermore, it goes without saying that the surface mount type multiple capacitors of the above-described embodiment may be formed by cutting out from a large-sized laminate by adopting a so-called 'multiple pick-up' technique.

  Furthermore, in the above-described embodiment, the internal electrodes are alternately arranged for each dielectric layer, but the present invention is not limited to this. At this time, even if the intervening interval is too wide, the dummy internal electrode that is not affected by the electrostatic capacity or the like is formed and exposed between the connecting internal electrodes, so that there is no effect. Electrical connection is facilitated by terminal electrodes and connecting conductors formed by electrolytic plating or the like.

  Furthermore, in the above-described embodiment, the dielectric layer in which the capacitor elements 4a, 4b, and 4c are formed in the region A between adjacent capacitor elements in the stacked body 1 where the internal electrodes 3a and 3b and the like are not present. 2 is formed of a dielectric layer made of the same dielectric material, and the porosity of the dielectric material forming the region A is determined by the porosity of the dielectric material forming the capacitor elements 4a, 4b, 4c. If it is made large, electrical interference between adjacent capacitor elements can be reduced well, and a multiple capacitor having desired characteristics can be obtained. Therefore, in the multilayer body 1, the region A between adjacent capacitor elements in which the internal electrodes 3 a, 3 b, etc. are not present is formed in the same material as the dielectric layer 2 forming the capacitor elements 4 a, 4 b, 4 c. The dielectric layer made of a body material is used, and the porosity of the dielectric material forming the region A is made larger than the porosity of the dielectric material forming the capacitor elements 4a, 4b, 4c. Is preferred.

1 is an external perspective view of a surface-mounted multiple capacitor according to an embodiment of the present invention. 1A is a cross-sectional view taken along line AA of the surface-mounted multiple capacitor in FIG. 1, FIG. 1B is a cross-sectional view taken along line BB of the surface-mounted multiple capacitor in FIG. 1, and FIG. It is a principal part enlarged view. FIG. 2 is an exploded perspective view of the surface mount type multiple capacitor of FIG. 1. It is an external appearance perspective view of the surface mount-type multiple capacitor | condenser which concerns on other embodiment of this invention. (A) is an external perspective view of a conventional multiple capacitor, and (b) is an exploded perspective view of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Dielectric layer 3a ... 1st internal electrode (internal electrode)
3b ... second internal electrode (internal electrode)
4a, 4b, 4c: Capacitor element 5a, 5b, 5c: Terminal electrode 6a, 6b, 6c: Connection conductor

Claims (3)

A large number of dielectric layers are laminated to form a rectangular parallelepiped laminate, and n pieces (n is a number) where a plurality of internal electrodes are interposed between adjacent dielectric layers inside the laminate. (2 or more natural number) capacitor elements are arranged in a line in the stacking direction of the dielectric layers, and a terminal electrode provided corresponding to each capacitor element is attached to the side surface of the stack. For ream capacitors,
The terminal electrode is connected in common to the outer peripheral portion of the internal electrode located in the central area of the capacitor element in the vicinity of the mounting surface of the multilayer body, and is positioned in both end areas with the internal electrode located in the central area of each capacitor element. A surface mount type multiple capacitor, wherein the inner electrode is electrically connected to the terminal electrode by a connecting conductor attached to a side surface of the multilayer body at a predetermined interval from the terminal electrode. . 2. The surface-mounted multi-layer according to claim 1, wherein the terminal electrode and the connecting conductor are made of an electroless plating film deposited on the surface of the multilayer body starting from an outer peripheral portion of each internal electrode. Ream capacitor. 3. The surface mount type multiple capacitor according to claim 1, wherein the connecting conductors of adjacent capacitor elements are arranged so as to be shifted in a direction orthogonal to the arrangement direction of the capacitor elements.

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