JP2012044112A - Device including capacitor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high capacity, low ESR and ESL device including a plurality of capacitor elements.SOLUTION: The device 1 has a first capacitor element 21, a lead frame 10, and a second capacitor element 22 laminated to sandwich the lead frame 10. The lead frame 10 includes an anode lead 11 connected electrically with the anode 31 of the first capacitor element 21 via a first bonding wire 41, and cathode leads 15 and 16 connected electrically with the cathode 32 of the first capacitor element 21. The anode lead 11 includes a part 11b for electrical connection extending outward from the first capacitor element 21 along a lateral direction Y perpendicular to the longitudinal direction X, but does not include a part for electrical connection extending outward from the first capacitor element 21.

Description

  The present invention relates to a capacitor employed in various electronic devices and a mounting device incorporating the capacitor.

  Patent Document 1 discloses a capacitor element substrate in which an anode portion is formed on one side of a flat valve action metal plate having a dielectric oxide film layer on the surface, and a cathode portion comprising a solid electrolyte layer and a cathode lead layer is formed on the other side. In a multilayer solid electrolytic capacitor in which a plurality of layers are stacked, it is described that the anode portions of the capacitor element substrate are alternately stacked so that the anode portions face each other centering on the cathode portion.

JP 2007-1116064 A

  Capacitors, which are one of the electronic components as the frequency of electronic equipment increases, are compact, large in capacity, and have high ESR (equivalent series resistance) and ESL in order to obtain excellent performance in noise removal and transient response. What has a low (equivalent series inductance) is desired.

  One aspect of the present invention is a plate-like first capacitor element including a first connection electrode portion at one end in a first direction and a second connection electrode portion at the other portion, a lead frame, It is a device having The lead frame includes a first lead portion electrically connected to the first connection electrode portion of the first capacitor element via a first bonding wire, and a second connection electrode portion of the first capacitor element. A second lead portion electrically connected to the first capacitor portion, and the first lead portion and the second lead portion from the first capacitor element along a second direction orthogonal to the first direction. The first lead portion and the second lead portion each include a portion serving as an electrical connection extending outward, and the first lead portion and the second lead portion extend outward from the first capacitor element along the first direction. Does not include the part to be used. The first bonding wire includes a portion extending in the second direction.

  The lead frame of this device extends in a second direction orthogonal to the first direction in which the first connection electrode portion and the second connection electrode portion are adjacent to each other, and the first direction It does not include a portion used for electrical connection with the capacitor element. Therefore, it is possible to reduce the distance between the first lead portion and the second lead portion with respect to the length of the first capacitor element in the first direction, and it is easy to reduce ESL. In particular, when the first capacitor element is long in the first direction, the distance between the first lead portion and the second lead portion can be easily reduced. Furthermore, since the lead frame does not include a portion for electrical connection in the first direction, the length of the lead frame in the first direction can be shortened, so that ESR can be easily reduced, and a compact and large-capacitance capacitor device can be obtained. Can be provided.

  The device has a second capacitor element stacked directly on the first capacitor element or across the lead frame, the second capacitor element being electrically connected to the lead frame. Also good. Increase device capacity. In addition, by incorporating capacitor elements having different capacities, a low impedance device can be provided in a wider frequency band.

  In particular, the first capacitor element and the second capacitor element are solid electrolytic capacitor elements, and the second connection electrode portion has a dielectric characteristic including a dielectric oxide film with respect to the base connected to the first connection electrode portion. And the thickness of the dielectric oxide film of the first capacitor element is different from the thickness of the dielectric oxide film of the second capacitor element. May be. By changing the thickness of the dielectric oxide film, which is a dielectric layer, the electrostatic capacity can be controlled and the withstand voltage can be changed.

  The second capacitor elements are stacked with the lead frame interposed therebetween, and the first connection electrode portion of the second capacitor element is opposite to the first connection electrode portion of the first capacitor element in the first direction. May be arranged. The lead frame includes a third lead portion electrically connected to the first connection electrode portion of the second capacitor element via the second bonding wire, and the third lead portion is the second lead portion. A portion for providing an electrical connection extending outward from the second capacitor element along the direction, and a portion for providing an electrical connection extending outward from the second capacitor element along the first direction Preferably, the second bonding wire includes a portion extending in the second direction.

  This device is a compact and large-capacity capacitor device, and is easy to provide a low ESR and low ESL device. Further, the first lead portion, the second lead portion, and the third lead portion may be prevented from being exposed to the outside from the first capacitor element and the second capacitor element along the first direction. It becomes possible. Furthermore, the first lead portion and the third lead portion may be integrated.

  A typical first capacitor element is a plate-like conductive base and an electrode layer formed by sandwiching at least a layer having dielectric properties on both sides of the base, and is provided in a hole penetrating the base. And an electrode layer electrically connected by the connecting layer, wherein at least a part of an end of one surface of the substrate is exposed to become a first connection electrode part, and at least a part of the electrode layer is a second electrode It is a device that is a connection electrode part. The device may have a resinous and square package that serves as an exterior of the device.

  Another aspect of the present invention is a printed wiring board on which the above device is mounted, and an electronic apparatus having the printed wiring board.

The perspective view which shows the outline | summary of a device. The perspective view which shows a device in the state which remove | excluded mold resin. Fig. 3 is a developed view of the device on a lead frame and capacitor element. The top view which shows a device in the state except mold resin. The side view which shows a device in the state except mold resin. Sectional drawing which shows the structure of a capacitor | condenser element. FIGS. 7A and 7B are diagrams for explaining the arrangement of capacitor elements, in which FIG. 7A is an example of the prior art, FIG. 7B is an example of a different arrangement, and FIG. The perspective view which shows the example from which a device differs. The top view which shows a part of printed wiring board carrying a device. The block diagram which shows the circuit containing a device. 11A shows an impedance curve of each capacitance of the device, FIG. 11B shows a synthesized impedance curve of the device, and FIG. 11C shows a comparison with the impedance curve according to the conventional method. 12A shows a conventional connection method, FIG. 12B shows an impedance curve of each capacitor, and FIG. 12C shows a synthesized impedance curve. FIG. 13A is a block diagram illustrating different application examples of the device, and FIG. 13B is a block diagram illustrating still another application example of the device. FIG. 14A is a perspective view showing still another example of the device. FIG. 14A shows a capacitor element by a broken line, and FIG. 14B shows a capacitor element by a solid line. FIG. 15A is a perspective view showing still another example of the device. FIG. 15A shows a capacitor element by a broken line, and FIG. 15B shows a capacitor element by a solid line.

  FIG. 1 shows an example of a device including a capacitor according to the present invention. The device 1 includes a capacitor 20, a lead frame 10 connected to the capacitor 20, and a package 50 that contains the capacitor 20 and a part of the lead frame 10 is exposed on the surface. The package 50 is made of an exterior resin (mold resin) 59 that is molded so as to be square or rectangular (rectangular) as a whole in a state in which the capacitor 20 is accommodated, and forms the external appearance of the capacitor device 1 for surface mounting. is doing. Hereinafter, the longitudinal direction of the device 1 will be described as the first direction X, and the short direction (lateral direction) orthogonal to the longitudinal direction X will be described as the second direction Y.

  FIG. 2 shows a state where the mold resin 59 of the device 1 is removed. FIG. 3 shows a state where the lead frame 10 and the capacitor 20 are separated. 4 and 5 show a plan view and a side view of the device 1 with the mold resin 59 removed. As the material of the lead frame 10 of the device 1, a material excellent in mechanical strength, electrical conductivity, thermal conductivity, corrosion resistance, etc., such as a copper-based material and an iron-based material is used. The lead frame 10 includes first and second anode terminal portions (anode leads) 11 and 12, and first and second cathode terminal portions (cathode leads, terminal portions for ground voltage) 15 and 16.

  Capacitor 20 includes a first capacitor element 21 and a second capacitor element 22 arranged to be stacked on first capacitor element 21 with lead frame 10 interposed therebetween. These capacitor elements 21 and 22 are plate-like solid electrolytic capacitors (solid electrolytic capacitor elements) as a whole, and the basic configuration is common. The capacitor elements 21 and 22 are generally long in the first direction X, and the first direction X coincides with the direction of the first connection electrode (anode) 31 with respect to the second connection electrode (cathode) 32. . Further, the first capacitor element 21 and the second capacitor element 22 are configured such that the first connection electrode portion 31 of the second capacitor element 22 is in relation to the first connection electrode portion 31 of the first capacitor element 21. The layers are stacked so as to be disposed on the opposite side of the first direction X.

  FIG. 6 is a cross-sectional view showing the configuration of the first capacitor element 21 as a representative. The capacitor element 21 has a flat plate shape as a whole and has a plate-like or thin-film valve action base 33 cut into a rectangular shape. The valve action base 33 includes a first surface (one surface, front surface) 33a and a second surface (the other surface, back surface) 33b that have been made porous (enlarged) by etching or the like. In this example, the side facing the lead frame 10 is referred to as a second surface (back surface) 33b. These surfaces 33a and 33b may be turned upside down or may face left and right.

  On the surface (one surface) 33a of the substrate 33, a dielectric oxide film 34a, a solid electrolyte layer 35a, and an electrode layer 36a are laminated in this order. Similarly, a dielectric oxide film 34b, a solid electrolyte layer 35b, and an electrode layer 36a are sequentially laminated on the back surface (the other surface) 33b of the base 33. Examples of the valve action base 33 include an etched aluminum foil, a tantalum sintered body, a niobium sintered body, and a titanium sintered body. A capacitor element using an etched aluminum foil is suitable for the thin device 1 for surface mounting.

  The dielectric oxide films 34a and 34b are aluminum oxide formed on the surface of the base 33 if it is an etched aluminum foil. The solid electrolyte layers 35a and 35b can be formed by laminating conductive polymers such as polypyrrole, polythiophene, and polyaniline on the dielectric oxide films 34a and 34b, respectively, by electrolytic polymerization, chemical polymerization, or the like. An example of the electrode layers 36a and 36b is a conductive paste laminated on the solid electrolyte layers 35a and 35b, respectively. The solid electrolyte layers 35a and 35b are substantial cathodes, and the electrode layers 36a and 36b constitute a cathode for ensuring conductivity, and a part thereof is a connection electrode portion (second connection electrode portion, cathode) 32. It becomes. Layers having dielectric properties formed between the substrate 33 and the electrode layers 36a and 36b or for exerting them satisfactorily are not limited to the dielectric oxide films 34a and 34b and the solid electrolyte layers 35a and 35b. In order to reduce resistance, it may include a solid electrolyte layer 35a, a highly conductive graphite layer laminated between the electrode layers 36a, and the like.

  Note that the electrode layers 36a and 36b described as functioning as cathodes in this specification are apparent cathodes, and the solid electrolyte layers 35a and 35b play a role of functioning as true cathodes. Therefore, the dielectric oxide films 34a and 34b are layers having dielectric characteristics. The same applies to the following. Hereinafter, the electrode layers 36 a and 36 b are referred to as the cathode 32.

  Further, a first insulating layer 39a is formed on the surface 33a of the base 33 to cover the entire periphery of the peripheral edge 36c of the electrode layer 36a. Further, a second insulating layer 39b is formed on the back surface 33b of the base body 33 so as to cover the entire periphery of the peripheral edge 36c of the electrode layer 36b. One end (edge) 31 in the longitudinal direction X of the surface 33a of the base body 33 appears (exposes) on the outer peripheral side of the first insulating layer 39a, and the connection electrode portion of the capacitor element 21 (first connection electrode portion, anode) ) 31. An example of the insulating layers 39a and 39b is a film made of an insulating resin such as a polyimide resin or an epoxy resin. The insulating layer 39 b on the back surface 33 b extends to the back side of the anode 31 and forms an insulating layer 39 c that covers the back side of the anode 31. The side surface of the base 33 is also covered with an insulating layer 39d.

  The capacitor element 21 further includes a through hole (through hole) 37 that penetrates the valve action base 33. A dielectric oxide film 34c and a solid electrolyte layer 35c are sequentially laminated on the inner peripheral surface 37a of these through holes 37 from the side in contact with the valve action base 33. Further, the through holes 37 are electrically conductive such as silver paste. The through electrode 38 is formed by filling the paste. Even on the inner peripheral surface 37a of the through-hole 37, the solid electrolyte layer 35c can be formed together with the surface of the substrate 33 by a method such as electrolytic polymerization, and can contribute to the capacitance of the capacitor. In addition, the through electrode 38 functions as a connection layer that electrically connects the electrode layers 36a and 36b.

  The number of through electrodes 38 provided in the capacitor elements 21 and 22 is not limited to two, but may be one or three or more. By providing the through electrode 38, the current path between the anode (first connection electrode portion) 31 and the cathode (second connection electrode portion) 32 can be shortened. Therefore, it is possible to provide capacitor elements 21 and 22 having low ESR and low ESL.

  In the device 1, the thicknesses of the dielectric oxide films 34 a and 34 b included in the capacitor elements 21 and 22 are different between the capacitor elements 21 and 22. The thickness t1 of the dielectric oxide films 34a and 34b of the first capacitor element 21 is 4 nm, for example, and the thickness t2 of the dielectric oxide films 34a and 34b of the second capacitor element 22 is 14 nm, for example. The thickness of the capacitor element is not limited to these. Such capacitor elements 21 and 22 having different thicknesses can be easily manufactured by changing the voltage (formation voltage of the substrate) when forming the dielectric oxide films 34a and 34b.

  The first capacitor element 21 and the second capacitor element 22 may have the same configuration. In this case, the capacitance of the device 1 can be increased by stacking the two capacitor elements 21 and 22. On the other hand, the capacitances of capacitor elements 21 and 22 can be changed by changing the thicknesses of dielectric oxide films 34a and 34b of capacitor elements 21 and 22. The capacitance of the capacitor element is generally proportional to the area and inversely proportional to the thickness of the dielectric oxide films 34a and 34b. Therefore, by changing the surface area covered with the dielectric oxide films 34a and 34b of the capacitor element and the thickness of the oxide films 34a and 34b, a plurality of capacitor elements having a capacitance difference of about 1: several hundreds or more can be combined into one device 1. Can be incorporated into. For example, the device 1 including the first capacitor element 21 having a capacity of 200 μF and the second capacitor element 22 having a capacity of 40 μF can be provided.

  Further, the withstand voltage (rated voltage) of the capacitor elements 21 and 22 can be changed by changing the dielectric oxide films 34a and 34b of the capacitor elements 21 and 22. The rated voltage of the capacitor element is approximately inversely proportional to the thickness of the dielectric oxide films 34a and 34b. Therefore, a plurality of capacitor elements having a rated voltage difference of about 1: several tens or more can be incorporated into one device 1. For example, the device 1 in which the first capacitor element 21 having the rated voltage of 2V and the second capacitor element 22 having the rated voltage of 6.3V are stacked with the lead frame 10 interposed therebetween can be provided.

  As shown in FIG. 2, the lead frame 10 includes a first anode terminal portion (first anode lead, first lead portion) 11 and a second anode terminal portion (second anode lead, third lead). A lead portion) 12, and first and second cathode terminal portions (reference voltage connection terminal portion, cathode lead, second lead portion) 15 and 16.

  As shown in FIGS. 4 and 5, in this device 1 (capacitor 20), the anode 31 of the first capacitor element 21 is made of a conductive metal wire (first wire) such as a gold wire, a copper wire, or an aluminum wire. Bonding wire) 41 is electrically connected to first anode lead 11 of lead frame 10, and anode 31 of second capacitor element 22 is electrically connected to second anode lead 12 by second bonding wire 42. Has been. These bonding wires 41 and 42 extend substantially in the longitudinal direction (first direction, longitudinal direction) X, but not in the orthogonal direction (second direction, short direction, width direction, lateral direction) Y. Yes.

  On the other hand, the cathode leads 15 and 16 of the lead frame 10 are sandwiched between the cathode 32 on the back surface 33 b of the first capacitor element 21 and the cathode 32 on the back surface 33 b of the second capacitor element 22, and these capacitor elements 21 and 22. Connected electrically and mechanically. The cathode leads 15 and 16 are usually connected to the ground side (ground circuit) of the circuit, and a reference voltage (ground voltage) is applied.

  The first and second anode leads 11 and 12 include first portions 11a and 12a extending in the longitudinal direction X and second portions 11b and 12b extending in the lateral direction Y, respectively, and are L-shaped or The shape is close to the T shape. Second portions 11b and 12b extending in the lateral direction Y extend outward from the capacitor elements 21 and 22 to the outside of the package 50, and are folded at an appropriate angle to electrically connect the device 1 to the outside. Used for.

  The first portions 11 a and 12 a are elongated in the longitudinal direction X, and are arranged in the longitudinal direction X of the capacitor elements 21 and 22. The portions 11c and 12c in the lateral direction Y of the first portions 11a and 12a are sandwiched between the capacitor elements 21 and 22. The portions 11d and 12d of the first portions 11a and 12a that are not sandwiched in the lateral direction Y appear outside the side surfaces of the capacitor elements 21 and 22 along the longitudinal direction X of the capacitor elements 21 and 22, and are bonded to the bonding wires 41 and 42. Can be connected to each. The portions 11c and 12c sandwiched between the capacitor elements 21 and 22 of the first portions 11a and 12a are sandwiched between the insulating layers 39b of the capacitor elements 21 and 22, and are electrically connected to the cathode 32 of the capacitor elements 21 and 22. It is designed not to touch. The portions 11c and 12c sandwiched between the first portions 11a and 12a may be insulated to prevent electrical contact.

  The lengths of the first portions 11a and 12a extending in the longitudinal direction X of the anode leads 11 and 12 in the longitudinal direction X do not substantially protrude from the capacitor elements 21 and 22 in the longitudinal direction X. Actually, considering the tolerance when the capacitor elements 21 and 22 are mechanically attached to the anode leads 11 and 12, as shown in FIG. 4 and the like, the longitudinal directions X of the respective first portions 11a and 12a are used. The ends 11e and 12e are designed so as to be slightly protruded (protruded) from the capacitor elements 21 and 22. However, the longitudinal ends 11e and 12e of the first portions 11a and 12a are designed not to protrude long enough to allow the bonding wires 41 and 42 to be electrically connected. For this reason, anode leads 11 and 12 extend outward from capacitor elements 21 and 22 along the longitudinal direction, and do not include a portion for electrical connection.

  Each of the cathode leads 15 and 16 also includes first portions 15a and 16a extending in the longitudinal direction X and second portions 15b and 16b extending in the lateral direction Y, and has a shape close to an L shape or a T shape. It has become. Second portions 15b and 16b extending in the lateral direction Y extend to the outside of the package 50 toward the outside of the capacitor elements 21 and 22, and are folded at an appropriate angle to electrically connect the device 1 to the outside. Used for.

  The first portions 15a and 16a are connected at a portion in contact with the cathode 32 of the capacitor elements 21 and 22, and a connection electrode 19 with the cathode 32 is formed. The area of the connection electrode 19 is smaller than the area of the cathode 32 of the capacitor elements 21 and 22. When the connection electrode 19 is sandwiched between the capacitor elements 21 and 22, the connection electrode 19 falls within the range of the cathode 32. It does not protrude outside the elements 21 and 22. Therefore, the connection electrodes 19 are sandwiched between the capacitor elements 21 and 22, and these are electrically and mechanically connected to the cathodes 32 of the capacitor elements 21 and 22 with a conductive paste or the like, so that the capacitor elements 21 and 22 are connected to the lead frame 10. A device 1 (capacitor 20) can be provided in which the cathode leads 15 and 16 are electrically connected in parallel and the capacitor elements 21 and 22 are mechanically connected to the cathode leads 15 and 16. The first portions 15a and 16a extending in the longitudinal direction X of the cathode leads 15 and 16 may be separated.

  In this device 1, the capacitor elements 21 and 22, the bonding wires 41 and 42, and the lead frame 10 are covered with an exterior resin (mold resin) 59 and packaged. However, the part required for external connection of the lead frame 10 is not covered with the mold resin 59. An example of the mold resin 59 is a sealing resin such as an epoxy resin. External connection portions of the anode leads 11 and 12 and the cathode leads 15 and 16 of the lead frame 10 appear outside the package 50 made of mold resin. The ends of the leads 11 and 12, 15 and 16 appearing on the outside of the package 50 are bent downward (back side) along the package 50, and the device 1 is used as a surface mounting device mounted on a circuit board or the like. Is done.

  In this device 1, as shown in FIG. 4, the package 50 has a rectangular shape (a rectangular parallelepiped), and the anode leads 11 and 12 are formed side by side on one side 51 extending in the longitudinal direction X of the package 50. The cathode leads 15 and 16 are formed side by side on the other side 52 extending in the longitudinal direction X of the package 50. Further, the bonding wires 41 and 42 extend in the lateral direction Y, and the lead frame 10 does not include a portion used for electrical connection in the longitudinal direction X. That is, the anode leads 11 and 12 and the cathode leads 15 and 16 include portions 11b, 12b, 15b, and 16b, respectively, provided for electrical connection extending outward from the capacitor elements 21 and 22 along the lateral direction Y. It does not include a portion for electrical connection extending outward from the capacitor elements 21 and 22 along the longitudinal direction X. Therefore, the length of the lead frame 10 in the longitudinal direction X can be shortened, and the length of the package 50 to be packaged including the lead frame 10 can be shortened. For this reason, the capacitor device 1 with a large capacity can be provided.

  In addition, the distance between anode leads 11 and 12 and cathode leads 15 and 16 can be reduced with respect to the length of capacitor elements 21 and 22 in the longitudinal direction X. For this reason, the capacitor device 1 having a large capacity and a lower ESL can be provided. In particular, when the capacitor elements 21 and 22 are long in the longitudinal direction X and short in the lateral direction Y, the distance between the anode leads 11 and 12 and the cathode leads 15 and 16 is reduced with respect to the capacity of the capacitor elements 21 and 22. Cheap. Therefore, it is possible to provide a capacitor device 1 that is compact, has a large capacity, and has a lower ESL.

  Even in a device having one capacitor element 41, the bonding wire 41 is extended in the lateral direction Y, and the lead frame 10 is a portion where the lead frame 10 extends outside the capacitor element 21 in the longitudinal direction X. By not including a portion for connection, the capacitor device 1 can be provided that is compact, large in capacity, and low in ESL as described above. In this device 1, the capacitor capacity can be further increased by overlapping the first and second capacitor elements 21 and 22 with the lead frame 10 interposed therebetween. Further, by changing the capacitance and / or withstand voltage of the first capacitor element 21 and the second capacitor element 22, the impedance can be further reduced in a wide frequency band, as described in detail below, or a substrate with a multi-power supply voltage can be obtained. It is possible to provide the device 1 in which the functions such as corresponding to the above are fused.

  Further, in this capacitor device 1, the longitudinal direction X coincides with the direction of the anode 31 with respect to the cathode 32 in each capacitor element 21 and 22, and extending the bonding wires 41 and 42 in the lateral direction Y means that the bonding wire 41 And 42 are extended in a direction orthogonal to the direction of the anode 31 with respect to the cathode 32, and the capacitance of the capacitor can be increased and ESR can be reduced. In a device including a capacitor element in which the lateral direction Y is the direction of the anode 31 with respect to the cathode 32, it is often difficult to increase the capacitance of the capacitor. On the other hand, by extending the bonding wire in the direction perpendicular to the direction Y of the anode 31 with respect to the cathode 32, that is, in the longitudinal direction X, the capacitor capacity can be increased and the ESR can be further reduced.

  FIG. 7 schematically shows a comparison with a device including a conventional solid electrolytic capacitor element. FIG. 7A shows an example of a conventional solid electrolytic capacitor element 75. The element 75 is entirely rectangular (a rectangular parallelepiped), the anode 71 appears at one end in the longitudinal direction X, and the anode terminal 73 and the cathode 74 face each other in the longitudinal direction X. Therefore, the length (L dimension) in the longitudinal direction X of the element 75 can be used to arrange the cathode 72, and a large area of the cathode 72 can be secured. For this reason, a large-capacity capacitor element 75 can be obtained. The anode terminal 73 and the cathode terminal 74 are also arranged opposite to the longitudinal direction X. The anode 71 and the anode terminal 73 of the element 75 are electrically connected by a lead or a bonding wire 79, and the cathode 72 and the cathode terminal 74 are electrically connected directly or by a conductive paste. In the element 75, the longitudinal direction X of the element 75 is a current path.

  One method of reducing the ESL of the element 75 is to shorten a loop length in which a current loops when connected. Therefore, the current path is preferably changed from the longitudinal direction X to the lateral direction (short direction) Y. In the solid electrolytic capacitor element 76 shown in FIG. 7B, the anode 71 and the cathode 72 and the anode terminal 73 and the cathode terminal 74 are both arranged in the short direction Y (so as to face each other). In this element 76, the current path is in the horizontal direction Y, and the distance (loop length) through which the current flows is shortened from the L dimension of the element 76 to the W dimension. Therefore, a low ESL device can be provided. However, the bonding wire 79 extends in the direction of the anode 71 with respect to the cathode 72, and the distance available for arranging the cathode 72 and the dielectric layer becomes the W dimension in the lateral direction Y. The area is reduced. Therefore, the capacitor capacity tends to decrease, and it is difficult to reduce the ESR of the device.

  In the solid electrolytic capacitor element 77 shown in FIG. 7C, the anode terminal 73 and the cathode terminal 74 are arranged in the lateral direction Y (so as to face each other), and the anode 71 and the cathode 72 are opposed in the longitudinal direction X (so as to face each other). Like). In this element 77, the current path is in the lateral direction Y, and the distance (loop length) through which the current flows is shortened from the L dimension of the element 77 to the W dimension. Therefore, ESL can be reduced. Furthermore, the bonding wire 79 extends in a direction perpendicular to the direction of the anode 71 with respect to the cathode 72, and the distance that can be used to arrange the cathode 72 and the dielectric layer is the L dimension in the longitudinal direction X. For this reason, the areas of the cathode 72 and the dielectric layer can be enlarged. Therefore, the capacitance of the capacitor can be increased, and a low ESR can be realized. In this way, by changing the connection direction of the bonding wire 79, converting only the connection direction of the solid electrolytic capacitor from the longitudinal direction X to the short direction Y, and reversing the connection direction from the L direction to the W direction, ESL and A device with low ESR can be provided.

  FIG. 8 shows examples of different devices. FIG. 8 is a perspective view showing the device 1a with the package 50 omitted. The basic configuration of the device 1 a is the same as that of the device 1 described above, and includes a capacitor 20 and a lead frame 10. The device 1a includes a first capacitor element 21 and a second capacitor element 22 which are stacked with the lead frame 10 interposed therebetween, and a small third capacitor stacked on the first capacitor element 21 having a large capacity. The capacitor element 23 is provided. Therefore, the device 1a has capacitor elements 21 to 23 arranged in a stacked manner, and the plurality of capacitor elements 21 to 22 are electrically connected in parallel. The third capacitor element 23 is stacked on a portion of the lower large-capacity first capacitor element 21 excluding the anode 31 such that the direction of the anode 31 with respect to the cathode 32 is the lateral direction Y. The third capacitor element 23 is also a solid electrolytic capacitor, and the basic configuration is common to the other capacitor elements 21 and 22.

  The lead frame 10 includes first to third anode leads 11 to 13 and first to third cathode leads 15 to 17. The anode 31 of the first capacitor element 21 is connected to the first anode lead 11 by the first bonding wire 41, and the anode 31 of the second capacitor element 22 is connected to the second anode lead 12 and the second bonding wire 42. The anode 31 of the third capacitor element 23 is connected to the third anode lead 13 by the third bonding wire 43. These bonding wires 41 to 43 extend substantially in the lateral direction Y.

  Also in this device 1a, the anode leads 11 to 13 and the cathode leads 15 to 17 of the lead frame include portions for electrical connection extending outward from the capacitor elements 21 to 23 along the lateral direction Y, respectively. It does not include a portion for electrical connection extending outward from the capacitor elements 21 to 23 along the direction X. Therefore, the length of the lead frame 10 in the longitudinal direction X can be shortened, and the length of the package 50 to be packaged including the lead frame 10 can be shortened. For this reason, the capacitor device 1 with a large capacity can be provided. Further, the anode leads 11 to 13 and the cathode leads 15 to 17 of the lead frame do not include a portion (protruding portion) exposed to the outside from the capacitor elements 21 to 23 along the longitudinal direction X. Therefore, the device 1a is a more compact surface mount device.

  In addition, the distance between the anode leads 11 to 13 and the cathode leads 15 to 17 can be reduced with respect to the length of the capacitor elements 21 to 23 in the longitudinal direction X. Therefore, it is possible to provide a capacitor device 1a having a large capacity, a compact size, and a lower ESL.

  The third capacitor element 23 is placed on the first capacitor element 21 so that the back electrode 36 b serving as the cathode 32 of the third capacitor element 23 becomes the cathode of the first capacitor element 21. It can be electrically connected to the electrode 36a on the surface to be 32 directly or via a conductive paste. Accordingly, the cathode 32 of the third capacitor element 23 is electrically connected to the first to third cathode leads 15 to 17 of the lead frame 10 via the cathode 32 of the first capacitor element 21. The areas of the cathode 32 and the dielectric layers 34a and 34b of the third capacitor element 23 are smaller than those of the other capacitor elements 21 and 22, and the capacitance is small. On the other hand, the dielectric layers 34 a and 34 b of the third capacitor element 23 are thicker than those of the other capacitor elements 21 and 22. Therefore, the device 1a includes three capacitor elements 21 to 23 having different capacitances and withstand voltages that are connected in parallel on the ground side. For example, a first capacitor element 21 having a rated voltage of 2V and a capacity of 200 μF, a second capacitor element 22 having a rated voltage of 6.3V and a capacity of 40 μF, and a third capacitor element 23 having a rated voltage of 25V and a capacity of 1 μF are included. Device 1 can be provided. These numbers are only examples.

  FIG. 9 schematically shows a part of the printed wiring board on which the device 1a is mounted. FIG. 10 is a block diagram of a power supply circuit including the device 1a. The printed wiring board (printed circuit board) 9 is, for example, a mother board of an electronic device such as a personal computer. A CPU 3 and a power supply block (not shown in FIG. 9) 2 are mounted on the printed wiring board 9, and a device 1 a is connected in parallel between the ground circuit 5 and the power supply circuit 4 connecting the power supply block 2 to the CPU 3. It is connected. The device 1a functions as a decoupling capacitor or a bypass capacitor.

  The capacitances (capacitor capacities) C1, C2, and C3 of the three capacitor elements 21 to 23 connected in parallel in the device 1a are different. Further, each of the capacitor elements 21 to 23 has the cathode 33 on the front surface 33a and the back surface 33b connected by the through electrode 38, the current path from the anode 31 to the cathode 32 is short, and the direction of current flow varies. . Accordingly, each capacitor element 21 to 23 has low ESR and low ESL. For this reason, the anode terminals (anode leads) 11, 12 and 13 of the device 1 a are connected to the power supply circuit 4, and the cathode terminals 15, 16 and 17 are connected to the ground circuit 5, thereby reducing the capacitance of low ESR and low ESL. Different elements 21 to 23 are connected in parallel. Therefore, by adopting the device 1a in the power supply circuit, the impedance can be lowered in a wide frequency band, and noises in a wide range of frequencies can be removed.

  FIGS. 11A to 11C schematically show how low impedance is realized in a wide frequency band. The impedance curve 61 of the capacitance C1 of the first capacitor element 21 having a large capacity, the impedance curve 62 of the capacity C2 of the second capacitor element 22 having a middle capacity, and a third capacitor having a small capacity as shown in FIG. The impedance curve 63 of the capacitor C3 of the capacitor element 23 is synthesized, and an impedance curve 64 having a broad low impedance in a wide frequency band as shown in FIG. 11B can be reproduced.

  As shown in FIG. 12A, conventionally, in order to obtain such characteristics, it has been necessary to connect a plurality of capacitor devices 29a to 29c having different capacities in parallel. The plurality of capacitor devices 29a to 29c having different capacities have different sizes, and are a combination of capacitors of different types (for example, tantalum capacitors, ceramic capacitors, etc.). For this reason, not only the capacities differ, but also the ESR and ESL differ, and the ESLs do not match as shown in FIG. Accordingly, as shown in FIG. 12C, the synthesized impedance curve 69 has a plurality of inflection points. Electrically, LC resonance will occur.

  On the other hand, as shown in FIG. 11B, since the device 1a stores the capacitor elements 21 to 23 having different capacitance characteristics in one package, other characteristics excluding the capacitance characteristics, that is, ESL and ESR are Be the same. Therefore, as shown in comparison with FIG. 11C, an impedance curve 64 showing a low impedance characteristic with less characteristic change over a wider frequency range than the impedance curve 69 is obtained. Therefore, it is possible to provide the device 1a that exhibits flat impedance characteristics with less occurrence of LC resonance.

  Furthermore, since a device having a plurality of capacitance characteristics can be provided by one device 1a, the space required for mounting a device for obtaining a plurality of capacitance characteristics can be reduced, and one application in which a large number of capacitors have conventionally been mounted can be achieved. Alternatively, it can be replaced by a few devices 1a. Therefore, it is suitable for electronic devices such as information processing terminals such as notebook personal computers, which are becoming more compact, and portable information processing terminals such as mobile phones and PDAs.

  FIG. 13 shows several examples of different uses of the device 1. FIG. 13A shows that a function as a decoupling capacitor or a bypass capacitor can be added to the power supply system of the semiconductor 3a having a plurality of voltage lines with one or few devices 1a. In an electronic device or a printed wiring board provided with a plurality of power supply blocks (switching power supplies) 2a, 2b and 2c, each capacitor element 21 of the device 1a is connected to each of a plurality of voltage lines (voltage circuits) 4a, 4b and 4c. 22 and 23 can be connected. As described above, the device 1a includes a plurality of capacitor elements 21 to 23 having different rated voltages. Therefore, the device 1a can cope with a plurality of voltages. Moreover, even if it is the same voltage line, when there exists a line which supplies several electric power, the device 1a can be adapted to each electric power line.

  FIG. 13B shows an example applied to a π-type filter. The existing π-type filter including the capacitor element has a drawback that the circuit adaptability is poor because the coil component (inductor) is arranged in the device. On the other hand, in the case of the device 1a, the coil components L1, L2, and L3 arranged in series can be made an open system that can be mounted on a printed wiring board or the like. Therefore, the coil components L1, L2, and L3 can be freely arranged by the wiring width, wiring length, or inductor device of the circuit pattern, and the π-type filter 6 suitable for the circuit to be mounted can be configured.

  FIGS. 14A and 14B show examples of different devices. In FIG. 14A, the package 1 is omitted from the device 1b, and the first capacitor element 21 and the second capacitor element 22 constituting the capacitor 20 are indicated by alternate long and short dash lines. In FIG. 14B, the first capacitor element 21 and the second capacitor element 22 are indicated by solid lines. The basic configuration of the device 1b is common to the device 1 described above, and includes a capacitor 20 and a lead frame 100. The lead frame 100 includes a first anode terminal portion (first anode lead, first lead portion) 11, a second anode terminal portion (second anode lead, third lead portion) 12, 1 and a second cathode terminal portion (connection terminal portion for reference voltage, cathode lead, second lead portion) 15 and 16. The structure of the lead frame 100 on the side of the cathode leads 15 and 16 is the same as that of the device 1 and includes a cathode frame 105 in which the cathode leads 15 and 16 are integrated. In the device 1b, the first and second anode leads 11 and 12 are also integrated with the first portions 11a and 12a extending in the longitudinal direction X thereof. That is, the anode terminal portions 11 and 12 of the device 1b are integrated to form a substantially π-shaped frame (anode frame) 101 as a whole.

  A portion 101 c of the anode frame 101 extending in the longitudinal direction X is sandwiched between the capacitor elements 21 and 22, and a portion 101 a that is not sandwiched is a side surface of the capacitor elements 21 and 22 along the longitudinal direction X of the capacitor elements 21 and 22. Appearing on the outside and bonding wires 41 and 42 are connected. The portion 101c sandwiched between the capacitor elements 21 and 22 may be insulated to prevent electrical contact.

  The length of the anode frame 101 in the longitudinal direction X is shorter than the length of the capacitor elements 21 and 22 in the longitudinal direction X, and does not physically protrude from the capacitor elements 21 and 22. Therefore, a portion 101a extending in the longitudinal direction X of the anode frame 101 and extending outward in the Y direction from the capacitor elements 21 and 22 is bonded to the capacitor elements 21 and 22 and the anode frame 101 by the bonding wires 41 and 42 extending in the lateral direction Y. And are used to electrically connect each other. For this reason, the anode frame 101 also extends outward from the capacitor elements 21 and 22 along the longitudinal direction, and does not include a portion used for electrical connection. Further, the anode frame 101 and the cathode frame 105 do not include a portion (a protruding portion) exposed to the outside from the capacitor elements 21 and 22 along the longitudinal direction X. Therefore, this device 1b is a compact surface mount device. The length in the longitudinal direction X of the anode frame 101 and the cathode frame 105 is slightly longer than the length in the longitudinal direction of the first and second capacitor elements 21 and 22, as in the anode lead of the lead frame 10 of the device 1. It may be longer, thereby ensuring tolerances during installation.

  FIGS. 15A and 15B show further examples of different devices. In FIG. 15A, the package 1 is omitted from the device 1c, and the first capacitor element 21 and the second capacitor element 22 constituting the capacitor 20 are indicated by alternate long and short dash lines. In FIG. 15B, the first capacitor element 21 and the second capacitor element 22 are indicated by solid lines. The basic configuration of the device 1c is common to the device 1 described above, and includes a capacitor 20 and a lead frame 110. The lead frame 110 includes a first anode terminal portion (first anode lead, first lead portion) 11, a second anode terminal portion (second anode lead, third lead portion) 12, A cathode frame 105 serving as first and second cathode terminal portions (connection terminal portion for reference voltage, cathode lead, second lead portion) 15 and 16.

  The cathode frame 105 of the lead frame 110 is entirely formed in a substantially Z-shape, and the second portions 15b and 16b of the cathode leads 15 and 16 are opposite to each other in the lateral direction Y (a 180-degree symmetrical side). It extends to. The first portions 15 a and 16 a extending in the longitudinal direction X of the cathode leads 15 and 16 are connected by a connection electrode 19 sandwiched between the capacitor elements 21 and 22.

  Each of the anode leads 11 and 12 includes a first portion 11a and 12a extending in the longitudinal direction X and a second portion 11b and 12b extending in the lateral direction Y, and one of the first portions 11a and 12a. Portions 11c and 12c are sandwiched between first and second capacitor elements 21 and 22, respectively. One anode lead 11 is disposed so as to face one cathode lead 15 in the lateral direction Y, and the other anode lead 12 is disposed so as to face the other cathode lead 16 in the lateral direction Y. Accordingly, the anode leads 11 and 12 extend on the opposite sides in the lateral direction Y (a side symmetrical with 180 degrees).

  In the device 1c including such a lead frame 110, the power source current flows in different directions through the device 1c as indicated by a thick broken line when mounted on a circuit board. That is, the direction of current passing through the inside of the device 1c is different. For this reason, the magnetic field component generated inside the device 1c is canceled, and a capacitor device with a lower ESL can be provided.

  Note that the capacitor devices described above are some examples of the present invention, and a method of stacking a plurality of capacitor elements having different capacities is not limited to the above-described embodiments. For example, a device in which a plurality of capacitor elements are stacked in three or more layers may be used. Further, the device for surface mounting according to the present invention can be used not only in combination with a CPU but also in combination with other circuit elements.

1, 1a, 1b, 1c Surface mount devices (capacitor devices)
10, 100, 110 Lead frame 20 Capacitor 21, 22, 23 Capacitor element 31 Anode (first connection electrode part), 32 Cathode (second connection electrode part)
33 Base

Claims (11)

A plate-like first capacitor element including a first connection electrode part at one end in the first direction and a second connection electrode part at the other part;
A lead frame,
The lead frame includes a first lead portion electrically connected to the first connection electrode portion of the first capacitor element via a first bonding wire, and the first lead portion of the first capacitor element. A second lead portion electrically connected to the two connection electrode portions, wherein the first lead portion and the second lead portion are in a second direction orthogonal to the first direction. Each of the first lead portion and the second lead portion extends in the first direction along the first direction. Does not include a portion for electrical connection extending outward from the capacitor element of
The device wherein the first bonding wire includes a portion extending in the second direction. The claim 1, further comprising:
A device comprising: a second capacitor element stacked directly on the first capacitor element or across the lead frame, the second capacitor element being electrically connected to the lead frame.   3. The dielectric property according to claim 2, wherein the second connection electrode portion of the first capacitor element and the second capacitor element includes a dielectric oxide film with respect to a base connected to the first connection electrode portion. And the thickness of the dielectric oxide film of the first capacitor element is different from the thickness of the dielectric oxide film of the second capacitor element. ,device. 4. The second capacitor element according to claim 3, wherein the second capacitor element is stacked with the lead frame interposed therebetween, and the first connection electrode portion of the second capacitor element is the first connection electrode of the first capacitor element. Disposed on the opposite side of the first direction with respect to the portion,
The lead frame includes a third lead portion electrically connected to the first connection electrode portion of the second capacitor element via a second bonding wire, and the third lead portion includes the third lead portion. A portion serving as an electrical connection extending outward from the second capacitor element along a second direction and extending outward from the second capacitor element along the first direction; It does not include parts for electrical connection,
The device wherein the second bonding wire includes a portion extending in the second direction.   5. The first lead portion, the second lead portion, and the third lead portion according to claim 4, wherein the first lead portion, the second lead portion, and the third lead portion are separated from the first capacitor element and the second capacitor element along the first direction. A device that is unexposed to the outside.   6. The device according to claim 4, wherein the first lead portion and the third lead portion are integrated.   2. The device according to claim 1, wherein the first capacitor element is long in the first direction.   2. The first capacitor element according to claim 1, wherein the first capacitor element is an electrode layer formed by sandwiching at least a plate-like conductive base and layers having dielectric properties on both surfaces of the base, and penetrates the base. An electrode layer electrically connected by a connection layer provided in the hole, and at least a part of an end of one surface of the base body is exposed to become a first connection electrode portion, and at least one of the electrode layers Device whose part is the second connection electrode part.   9. The device according to claim 1, wherein the device has a resinous and square package as an exterior of the device.   A printed wiring board on which the device according to claim 9 is mounted.   An electronic device comprising the printed wiring board according to claim 10.

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