JP2005285994A - Surface-mounted multiple capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounted multiple capacitor that can effectively prevent the occurrence of short circuits between solder adhered to terminal electrodes even when the size of the whole structure of the capacitor is reduced by narrowing the interval between adjacent capacitor elements and is excellent in mountability. <P>SOLUTION: The surface-mounted multiple capacitor is manufactured by forming a rectangular parallelepiped laminate by laminating many dielectric layers upon another and, at the same time, arranging n-pieces (wherein, n is a natural number of ≥2) of capacitor elements formed by respectively interposing a plurality of internal electrodes between adjacent dielectric layers in a row in the direction of lamination of the dielectric layers, and sticking the terminal electrodes provided correspondingly to the capacitor elements to the side faces of the laminate. The terminal electrodes are commonly connected to the outer peripheral sections of the internal electrodes positioned to the central areas of the capacitor elements, at least, near the mounting surface of the laminate. At the same time, the internal electrodes positioned to the central areas and both end areas of the capacitor elements are electrically connected to each other at portions of the side faces of the laminate separated from the mounting surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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, as shown in FIG. 5, a plurality of capacitor elements 24a, 24b, 24c are provided in a laminated body 21 in which a large number of dielectric layers 22 made of barium titanate or the like are laminated. And 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 of the multilayer body 21 is known (see, for example, Patent Document 1). .

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

  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 its purpose is to reduce the overall structure by reducing the interval between adjacent capacitor elements, so that the solder attached to the terminal electrodes can be connected to each other. It is an object of the present invention to provide a surface mount multiple capacitor excellent in mountability that can effectively prevent short circuit.

  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 at least in the vicinity of the mounting surface of the laminate. The internal electrode located in the central area of the capacitor element and the internal electrodes located in both end areas are electrically connected to each other at a part of the side surface of the laminate that is separated from the mounting surface. .

  Further, the surface mount type multiple capacitor of the present invention is characterized in that the terminal electrode is composed of an electroless plating film deposited on the surface of the laminate from the outer peripheral portion of each internal electrode. is there.

  Further, in the surface mount type multiple capacitor of the present invention, the connecting portion that electrically connects the internal electrode located in the central area of the capacitor element and the internal electrode located in both end areas is adjacent to each other, It is characterized by being shifted in a direction orthogonal to the arrangement direction.

  According to the surface mount type multiple capacitor of the present invention, the internal electrode located in the central region of the capacitor element is connected to the terminal electrode on the surface of the multilayer body in the vicinity of the mounting surface of the multilayer body and located in the central area of the capacitor element. Since the internal electrode and the internal electrode located at both end regions are electrically connected at a location separated from the mounting surface of the laminate, the interval between adjacent capacitor elements is reduced to reduce the overall structure. Even in this case, the width of the terminal electrode in the vicinity of the mounting surface can be set to a narrow width equivalent to the width of the central region, so that a wide interval between the adjacent terminal electrodes can be secured. Therefore, when a surface mount type multiple capacitor is 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 contacts the adjacent solder and causes a short circuit. Is effectively prevented.

  In addition, according to the surface mount type multiple capacitor of the present invention, the internal electrode connected to the terminal electrode is connected to the internal electrode located in both end regions at a portion separated from the mounting surface of the laminate. Therefore, even when the molten solder crawls up along the terminal electrode when mounted on an external electric circuit, it rarely rises to the vicinity of the terminal electrode connecting portion described above, and the connecting portion of the adjacent terminal electrode There is almost no risk of short-circuiting each other through the solder.

  Further, according to the surface mount type multiple capacitor of the present invention, the terminal electrode on the surface of the multilayer body is formed by an electroless plating film deposited on the surface of the multilayer body starting from the outer peripheral portion of each internal electrode. The terminal electrode can be formed by simple processing by simply immersing the laminate with the outer periphery of the electrode partially exposed in a plating solution for electroless plating for a predetermined time. It is also possible to improve the productivity of the capacitor.

  Furthermore, according to the surface mount type multiple capacitor of the present invention, the connecting portions that electrically connect the internal electrode located in the central area of the capacitor element and the internal electrodes located in both end areas are adjacent to each other. By disposing in a direction perpendicular to the arrangement direction of the adjacent connection, even when the solder that has been melted crawls up to the vicinity of the connection portion through the terminal electrode when mounted on the external electric circuit, the adjacent connection It is possible to effectively prevent the parts 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 5b arranged also extend to the side surface of the multilayer body 1 at a part of the outer periphery, and the other terminal electrodes 5a and 5b at least in the region including the vicinity of the mounting surface of the multilayer body 1 , 5c.

  Of the internal electrodes 3a and 3b, the internal electrodes 5a and 5b located in both end regions of the capacitor elements 4a, 4b and 4c are portions of the side surface of the multilayer body 1 separated from the mounting surface, for example, the lamination of the multilayer body 1 The internal electrodes located in the central region of the capacitor elements 4a, 4b, 4c are electrically connected via the terminal electrodes 5a, 5b near the center in the direction orthogonal to the direction, and this portion (hereinafter referred to as a connecting portion). Thus, all the first internal electrodes 3a provided in the capacitor elements 4a, 4b, 4c are connected to one terminal electrode 5a, 5b, 5c, and all the second internal electrodes 3b are connected to the other terminal electrode 5a, Commonly connected to 5b and 5c.

  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 0.5 μm to 8.0 μm, for example. Conductor 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 the body 1 is conventionally known screen printing, etc. It is formed by applying to 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 used as 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 solder or the like, 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 so that the mounting operation can be performed without taking the vertical direction into consideration, and when the terminal electrodes 5a, 5b, 5c and the connection pads of the external wiring board are soldered, the solder actually gets wet. The region is a lower region of the terminal electrodes 5a, 5b, 5c, for example, a region from the lower end of the terminal electrodes 5a, 5b, 5c to about one third in the height direction.

  These terminal electrodes 5a, 5b, and 5c are formed by, for example, a conventionally known electroless plating method, specifically, depositing metal on the surface of the laminate 1 starting from the outer peripheral portion of each internal electrode 3a, 3b. These precipitates are formed by interconnecting each other. When the terminal electrodes 5a, 5b, 5c are formed by electroless plating, the cross section has a shape as shown in FIG. 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.

  Thus, in the surface mount type multiple capacitors described above, n 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 , 4b, 4c, a predetermined voltage is applied through a pair of terminal electrodes 5a, 5b, 5c 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 as described above, the internal electrodes 3a and 3b located in the center area of the capacitor elements 4a, 4b and 4c are connected to the terminals on the surface of the multilayer body in the vicinity of the mounting surface of the multilayer body 1. Connected to the electrodes 5a, 5b, 5c, and the internal electrodes 3a, 3b located in the center area of the capacitor elements 4a, 4b, 4c and the internal electrodes 3a, 3b located in both end areas are separated from the mounting surface of the multilayer body 1 Even if the overall structure is downsized by narrowing the interval between adjacent capacitor elements, the terminal electrodes 5a, 5b, The width of 5c is a narrow width equivalent to the width of the central area of the capacitor elements 4a, 4b, 4c, so that a wide interval between adjacent terminal electrodes can be secured. Accordingly, when the surface mount type multiple capacitors are mounted on an external electric circuit such as a mother board by soldering, the solder that joins the terminal electrodes 5a, 5b, 5c and the connection pads of the external wiring board comes into contact with the adjacent solder. This effectively prevents a short circuit from occurring.

  In addition, the internal electrodes 3a, 3b connected to the terminal electrodes 5a, 5b, 5c are connected to the internal electrodes 3a, 3b located in both end regions at a portion separated from the mounting surface of the laminate 1. Therefore, even when the molten solder crawls up along the terminal electrodes 5a, 5b, and 5c when mounted on the external electric circuit, it does not rise to the vicinity of the connecting portion of the terminal electrodes 5a, 5b, and 5c. There is little possibility that the connecting portions of the adjacent terminal electrodes 5a, 5b, and 5c are short-circuited via solder.

  In the above-described embodiment, as shown in FIG. 4, the internal electrodes 3a, 3b located in the central area of the capacitor elements 4a, 4b, 4c and the internal electrodes 3a, 3b located in both end areas are electrically connected. If the parts are arranged so as to be shifted from each other in the direction orthogonal to the arrangement direction of the capacitor elements 4a, 4b, 4c, the surface mount type multiple capacitors are mounted on the external electric circuit by soldering. In this case, even if the molten solder crawls up to the vicinity of the connecting portion through the terminal electrodes 5a, 5b, and 5c, the tip portions of the adjacent connecting portions are separated from each other, so this portion is short-circuited via the solder. This is effectively prevented. Therefore, the connecting portions that electrically connect the internal electrodes 3a, 3b located in the center area of the capacitor elements 4a, 4b, 4c and the internal electrodes 3a, 3b located in both end areas are adjacent to each other, the capacitor element 4a. , 4b, 4c are preferably shifted in the direction perpendicular to the arrangement direction.

  Furthermore, in the above-described embodiment, the dielectric layer 2 forming the capacitor elements 4a, 4b, and 4c in the region 1 between the adjacent capacitor elements in the stacked body 1 where the internal electrodes 3a and 3b and the like are not present. And the porosity of the dielectric material forming the region A is larger than the porosity of the dielectric material forming the capacitor elements 4a, 4b, 4c. As a result, it is possible to satisfactorily reduce electrical interference between adjacent capacitor elements and to obtain a multiple capacitor having desired characteristics. 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.

  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 embodiment described above, the internal electrodes are alternately arranged for each dielectric layer, but the present invention is not limited to such a form. Even when the intervening spacing is too wide, by forming and exposing a dummy electrode that is not affected by capacitance etc. between the connecting internal electrodes, an electroless plating method, etc. It can be easily connected by the terminal electrode and the connecting conductor formed in (1).

1 is an external perspective view of a surface-mounted multiple capacitor according to an embodiment of the present invention. (A) is the sectional view on the AA line of the surface mount-type multiple capacitor of FIG. 1, (b) is the BB sectional view of the surface-mount type multiple capacitor of FIG. 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. It is sectional drawing of the conventional multiple capacitor | condenser.

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 elements 5a, 5b, 5c: Terminal electrodes

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 commonly connected at least in the vicinity of the mounting surface of the multilayer body to the outer peripheral portion of the internal electrode located in the central region of the capacitor element, and at a portion of the side surface of the multilayer body that is separated from the mounting surface. A surface mount type multiple capacitor characterized in that an internal electrode located in a central area of a capacitor element and an internal electrode located in both end areas are electrically connected. 2. The surface mount type multiple capacitor according to claim 1, wherein the terminal electrode is made of an electroless plating film deposited on the surface of the multilayer body starting from the outer peripheral portion of each internal electrode. The connecting portions that electrically connect the internal electrodes located in the central area of the capacitor element and the internal electrodes located in both end areas are arranged so as to be shifted from each other in a direction perpendicular to the arrangement direction of the capacitor elements. The surface mount type multiple capacitor according to claim 1, wherein the surface mount type multiple capacitor is provided.

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