JP2006319113A - Plate mounting solid electrolytic capacitor and method for manufacturing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lower an equivalent series resistance (ESR) between an anode lead terminal and a cathode lead terminal in the state that an enlargement is avoidable as much as possible. <P>SOLUTION: A solid electrolytic capacitor consists of a capacitor element 2 formed by projecting an anode bar 2b from a chip object 2a which hardens and sinters the powder of a valve action metal, forms a cathode film 2c through a dielectric film and a solid electrolyte layer in the periphery of the chip object; an anode lead terminal 3 linked to the anode bar in the capacitor element; and a cathode lead terminal 4 linked to the cathode film in the capacitor element. The capacitor element and both the lead terminals are made by sealing so that the lower surface of the both lead terminals with the package object 6 made of a synthetic resin is exposed to the bottom of the package object, the capacitor element 2 is made into a plurality, the plurality of the capacitor elements 2 are arranged in parallel in the width direction of the both lead terminals so that the cathode film in each may be mutually close, each anode bar is connected to the anode lead terminal 3, and each cathode film is connected to the cathode lead terminal 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface mount type solid electrolytic capacitor comprising a pair of lead terminals for mounting on a printed circuit board or the like among solid electrolytic capacitors using a valve action metal such as tantalum or niobium, and the like. And a manufacturing method.

  In general, this type of solid electrolytic capacitor, as described in Patent Document 1, for example, projects an anode rod from a chip body formed by sintering a valve action metal powder such as tantalum or niobium into a porous body and sintering it. On the other hand, after forming a dielectric film on the surface of the metal powder in the chip body, a capacitor film is formed by forming a cathode film on the outer peripheral surface of the chip body with a solid electrolyte layer as a base. The anode lead terminal and the cathode lead terminal are fixed to the anode rod and the cathode film on the outer periphery of the chip body of the capacitor element, respectively, and the anode lead terminal and the cathode lead terminal portion are printed. It is configured to be soldered to a circuit board or the like.

By the way, the capacitor element in this type of solid electrolytic capacitor has the advantage that the capacity per unit volume is large due to the large area on the surface of the solid electrolyte layer that is in contact with the dielectric film. The area of the surface of the solid electrolyte layer that is not in contact with the dielectric film is substantially equal to the outer peripheral area of the chip body, and the area of the solid electrolyte layer that is in contact with the dielectric film is the same. By being much smaller than the area on the surface, the solid electrolyte layer has a considerably large equivalent series resistance (ESR), and this equivalent series resistance (ESR) is a dielectric film of the solid electrolyte layer. It is known that it is approximately inversely proportional to the surface area of the portion that does not contact the surface.
JP 2003-68576 A

  However, in the capacitor element described above, the area of the solid electrolyte layer formed with respect to the outer periphery of the chip body on the side not in contact with the dielectric film, that is, on the surface opposite to the dielectric film is In order to reduce the equivalent series resistance (ESR) in the solid electrolyte layer, the area on the surface of the solid electrolyte layer that is not in contact with the dielectric film is increased. Since the outer peripheral area of the chip body must be increased, and thus the outer dimensions of the chip body must be increased, the capacitor element is increased in size, and consequently the solid electrolytic capacitor as a finished product is increased in size and weight. There was a problem to do.

  An object of the present invention is to provide a surface mount type solid electrolytic capacitor that solves this problem and a method for manufacturing the same.

In order to achieve this technical problem, a surface mount type solid electrolytic capacitor according to the present invention comprises:
“A capacitor element in which an anode rod protrudes from a chip body in which a powder of a valve metal is solidified and sintered, and a cathode film is formed on the outer periphery of the chip body via a dielectric film and a solid electrolyte layer; An anode lead terminal connected to the anode rod and a cathode lead terminal connected to the cathode film in the capacitor element, and the capacitor element and both lead terminals are made of a synthetic resin package body, and the lower surfaces of the two lead terminals. In a solid electrolytic capacitor that is hermetically sealed so as to be exposed on the bottom surface of the package body,
A plurality of the capacitor elements are arranged, and the plurality of capacitor elements are arranged in parallel in the width direction of the two lead terminals so that the cathode films in each of the capacitor elements are in close contact with each other. The anode lead terminal is connected, and the cathode film in each is connected to the cathode lead terminal. "
It is characterized by that.

As described in claim 2, the manufacturing method of the present invention comprises:
“A process of punching a lead frame from a metal plate and providing the lead frame with an anode lead terminal and a cathode lead terminal constituting one solid electrolytic capacitor at an appropriate pitch interval,
A first capacitor element is provided at each anode lead terminal and cathode lead terminal portion of the lead frame, an anode rod protruding from the chip body is used as the anode lead terminal, and a cathode film on the outer periphery of the chip body is provided as the cathode lead. A process of attaching to each terminal,
A second capacitor element is placed in close contact with the first capacitor element at each anode lead terminal and cathode lead terminal of the lead frame, and the anode rod of the second capacitor element is attached to the anode lead terminal. Attaching the cathode film of the second capacitor element to each of the cathode lead terminals;
Forming a synthetic resin package body that seals each capacitor element and both lead terminals at the location of each lead terminal so that the bottom surfaces of the lead terminals are exposed on the bottom surface of the package body;
Cutting each of the lead terminals from the lead frame;
It has. "
It is characterized by that.

Further, the manufacturing method of the present invention, as described in claim 3,
“The step of attaching the first capacitor element is a step of simultaneously attaching a plurality of the first capacitor elements to a plurality of locations, and the step of attaching the second capacitor element is the step of attaching the second capacitor element. This is a process of attaching a plurality to a plurality of locations at the same time. "
It is characterized by that.

  With the configuration described in claim 1, each capacitor element is provided in parallel between the anode lead terminal and the cathode lead terminal. Therefore, among the solid electrolyte layers of the capacitor element as a whole, The surface area on the side that is not in contact with the dielectric film, that is, on the surface opposite to the dielectric film, can be greatly increased as compared with the case where the whole is configured as one capacitor element.

  On the other hand, since the capacitor elements are in close contact with each other and there is no gap between them, an increase in size can be avoided.

  That is, according to the present invention, it is possible to greatly improve the equivalent series resistance (ESR) between the anode lead terminal and the cathode lead terminal in a state where enlargement of the solid electrolytic capacitor can be avoided as much as possible.

  In addition, according to the present invention, a surface mount type solid electrolytic capacitor having the above-described effects can be mass-produced at low cost using a lead frame.

  In particular, according to the method described in claim 3, since the capacitor element is attached to the lead frame and is performed for each of the plurality of capacitor elements, the productivity can be further improved, so that the cost can be further reduced. be able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1, 2 and 3 show a surface mount type solid electrolytic capacitor 1 according to an embodiment of the present invention.

  In this figure, reference numeral 2 denotes a first capacitor element, 2 'denotes a second capacitor element, and 2 "denotes a third capacitor element. These capacitor elements 2, 2' , 2 ″ project the anode rod 2b from the chip body 2a obtained by solidifying and sintering the valve action metal powder, and provide a dielectric film and a solid electrolyte layer (both not shown) on the outer periphery of the chip body 2a. In this configuration, the cathode film 2c is formed.

  Reference numeral 3 denotes an anode lead made of a metal plate, and reference numeral 4 denotes a cathode lead terminal also made of a metal plate.

  The lead terminals 3 and 4 are arranged at an appropriate interval, and the capacitor elements 2, 2 ′ and 2 ″ are disposed on the upper surface of the lead terminals 3 and 4, so that the cathode film 2 c is in close contact with each other. The terminals 3 and 4 are arranged in parallel in the width direction, and the anode rod 2b of each capacitor element 2, 2 ', 2 "is welded to the protrusion 3a provided on the upper surface of the anode lead terminal 3. On the other hand, the cathode film 2 c in the chip body 2 a of each capacitor element 2, 2 ′, 2 ″ is fixed and connected to the cathode lead terminal 4 with the conductive paste 5.

  The capacitor elements 2, 2 ′, 2 ″ and the lead terminals 3, 4 are connected to the lead terminals on the bottom surface of the package body 6 by a package body 6 made of a thermosetting synthetic resin such as epoxy resin. Seal so that the lower surfaces of 3 and 4 are exposed.

  The solid electrolytic capacitor 1 having this configuration can be mounted on a printed circuit board or the like by soldering with both lead terminals 3 and 4 exposed on the lower surface of the package body 6.

  In this case, since a plurality of capacitor elements 2, 2 ′, 2 ″ are provided in parallel between the anode lead terminal 3 and the cathode lead terminal 4, the capacitor element as a whole is arranged. The surface area of the solid electrolyte layer on the side not in contact with the dielectric film, that is, on the surface opposite to the dielectric film, can be greatly increased as compared with the case where the whole is formed as one capacitor element.

  On the other hand, the capacitor elements 2, 2 ′, 2 ″ are close to each other and there is no gap between them, so that an increase in size can be avoided.

  The solid electrolytic capacitor 1 having the above-described configuration is manufactured by the method described below.

  First, as shown in FIGS. 4 and 5, a lead frame A is formed from a metal plate, and a plurality of anode lead terminals 3 and cathode lead terminals 4 constituting one solid electrolytic capacitor 1 in the lead frame A are arranged in the longitudinal direction. They are integrally formed at appropriate intervals of the pitch P and punched, and projections 3 a are provided on the upper surfaces of the anode leads 3.

  On the other hand, each capacitor element 2, 2 ', 2 "is sintered after the valve action metal powder is formed into a porous chip body 2a so that the anode rod 2b protrudes from the chip body 2a. As shown in FIG. 6, a plurality of the chip bodies 2a are fixed to the horizontal bar B by welding the anode bar 2b to the horizontal bar B. In this state, the chip bodies 2a are fixed to the chip bodies 2a. It is manufactured by forming a dielectric film, a solid electrolyte layer, and a cathode film 2c.

  In this case, the interval pitch P for fixing the plurality of chip bodies 2a to the horizontal bar B is set to be equal to the interval pitch P between the lead terminals 3 and 4 of the lead frame A.

  Of the capacitor elements 2, 2 ′, 2 ″, a plurality of first capacitor elements 2, a plurality of second capacitor elements 2 ′, and a plurality of third capacitor elements 2 ″ , Each is manufactured in a state of being fixed to the horizontal bar B separately.

  Then, as shown in FIGS. 7 and 8, a plurality of first capacitor elements 2 manufactured using the horizontal bar B are simultaneously supplied to each of the lead terminals 3 and 4 in the lead frame A. The anode rod 2b in each first capacitor element 2 is fixed and connected to the projection 3a of the anode lead terminal 3 by welding, while the cathode film 2c in each first capacitor element 2 is connected to the cathode The lead terminal 4 is fixed and connected with a conductive paste.

  Next, the anode bar 2b is cut outside the protruding portion 3a of the anode lead terminal 3, thereby separating the horizontal bar B. As a result, both lead terminals of the lead frame A as shown in FIG. The first capacitor element 2 is attached to each of the points 3 and 4.

  The anode rod 2b may be cut with a blade, but a notch 2b 'is provided in advance at the cut portion of the anode rod 2b and welded. As indicated by the dotted line, the upper portion may be pulled upward and bend and cut at the notch (cut) 2b '.

  Next, as shown in FIG. 10, a plurality of second capacitor elements 2 'manufactured using the horizontal bar B are provided at the positions of the lead terminals 3 and 4 in the lead frame A, as shown in FIG. The anode rod 2b in each of the second capacitor elements 2 'is fixed and connected to the projection 3a of the anode lead terminal 3 by welding so as to be in close contact with the capacitor element 2, while The cathode film 2 c in the second capacitor element 2 ′ is fixed and connected to the cathode lead terminal 4 with a conductive paste, and the anode bar 2 b is cut outside the protrusion 3 a in the anode lead terminal 3. The horizontal bar B is separated by

  Next, as shown in FIG. 11, a plurality of third capacitor elements 2 ″ manufactured using the horizontal bar B are provided at the positions of both lead terminals 3 and 4 in the lead frame A, as shown in FIG. The anode rod 2b of each third capacitor element 2 ″ is supplied simultaneously so as to be in close contact with the capacitor element 2 ′, and resistance welding is performed by pressing the electrode element C against the protrusion 3a of the anode lead terminal 3. On the other hand, the cathode film 2 c in each third capacitor element 2 ″ is fixed and connected to the cathode lead terminal 4 with a conductive paste, and the anode rod 2 b is connected to the projection on the anode lead terminal 3. The horizontal bar B is cut by cutting outside the portion 3a.

  Thus, as shown in FIG. 12, three capacitor elements 2, 2 ', 2 "are mounted in close contact with each other at the locations of both lead terminals 3, 4 in the lead frame A.

  Next, as shown in FIG. 13, the package body 6 is formed by transfer molding at each of the locations of the lead terminals 3 and 4 in the lead frame A, and the lead terminals 3 and 4 are then transferred to the package body. The solid electrolytic capacitor 1 having the configuration shown in FIGS. 1 to 3 can be obtained by cutting the lead frame A from the lead frame A.

  When supplying the second capacitor element 2 ′ to the lead frame A, the lead frame A is supplied from the state in which the first capacitor element 2 is supplied to the lead frame A by an interval S between the capacitor elements. When the third capacitor element 2 ″ is supplied to the lead frame A by using the same device, the lead frame A is further shifted by the interval S between the capacitor elements. , Each capacitor element can be supplied to the lead frame.

  Further, of the lead terminals 3 and 4 in the lead frame A, holes 3b and 4a are formed in advance in the cut portions outside the package body 6 for easy cutting.

It is a vertical front view of the solid electrolytic capacitor by embodiment of this invention. FIG. 3 is a sectional view taken along line II-II in FIG. 2. 1 is a perspective view of a solid electrolytic capacitor according to an embodiment of the present invention. It is a top view of the lead frame used for manufacture. FIG. 5 is a VV sectional view of FIG. 4. It is a perspective view which shows the state which manufactures the capacitor | condenser element. It is a top view in the state where the 1st capacitor element was supplied to the lead frame. It is VIII-VIII sectional view taken on the line of FIG. It is sectional drawing of the state which mounted | wore the lead | read | reed frame with the capacitor | condenser element. It is a top view in the state where the 2nd capacitor element was supplied to the lead frame. It is a top view in the state where the 3rd capacitor element was supplied to the lead frame. FIG. 6 is a plan view of a state in which three capacitor elements are mounted on the lead frame. It is a top view which shows the state which shape | molded the package body in the lead frame.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Solid electrolytic capacitor 2 Capacitor element 2a Chip body 2b Anode rod 2c Cathode film 3 Anode lead terminal 4 Cathode lead terminal 5 Conductive paste 6 Package body A Lead frame B Horizontal bar C Welding electrode

Claims (3)

A capacitor element in which an anode rod protrudes from a chip body obtained by solidifying and sintering a valve action metal powder, and a cathode film is formed on the outer periphery of the chip body via a dielectric film and a solid electrolyte layer, and an anode in the capacitor element An anode lead terminal connected to the rod and a cathode lead terminal connected to the cathode film in the capacitor element. The capacitor element and both lead terminals are made of a synthetic resin package, and the lower surfaces of both lead terminals are In a solid electrolytic capacitor that is sealed so as to be exposed on the bottom surface of the package body,
A plurality of the capacitor elements are arranged, and the plurality of capacitor elements are arranged in parallel in the width direction of the two lead terminals so that the cathode films in each of the capacitor elements are in close contact with each other. A surface mount type solid electrolytic capacitor, characterized in that it is connected to the anode lead terminal, and a cathode film in each of the anode lead terminals is connected to the cathode lead terminal. A step of punching a lead frame from a metal plate and providing the lead frame with anode lead terminals and cathode lead terminals constituting one solid electrolytic capacitor at appropriate pitch intervals;
The first capacitor element is placed at each anode lead terminal and cathode lead terminal portion of the lead frame, the anode rod protruding from the chip body is the anode lead terminal, and the cathode film on the outer periphery of the chip body is the cathode lead terminal. Attaching to connect to each other,
A second capacitor element is placed in close contact with the first capacitor element at each anode lead terminal and cathode lead terminal of the lead frame, and the anode rod of the second capacitor element is attached to the anode lead terminal. Attaching the cathode film of the second capacitor element to each of the cathode lead terminals;
Forming a synthetic resin package body that seals each capacitor element and both lead terminals at the location of each lead terminal so that the bottom surfaces of the lead terminals are exposed on the bottom surface of the package body;
Cutting each of the lead terminals from the lead frame;
A method for producing a surface-mounted solid electrolytic capacitor, comprising:   The step of attaching the first capacitor element is a step of simultaneously attaching a plurality of the first capacitor elements to a plurality of locations, and the step of attaching the second capacitor element includes a plurality of the second capacitor elements. A method of manufacturing a surface mount type solid electrolytic capacitor, characterized in that it is a step of simultaneously mounting a plurality of pieces at a plurality of locations.

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