JP2005005522A - Chip type capacitor and its manufacturing method, and lead frame used for capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chip type capacitor capable of forming a fillet essential for a stabilization of a packaging posture of a product without adding an extra manufacturing process. <P>SOLUTION: A chip type capacitor is manufactured by the steps of exposing a capacitor element 2 and a bottom part to a packaging face 9 side of an exterior resin 1, welding an end of an anode terminal 5 as crossing to an anode lead wire 3 coming out from the capacitor element 2, connecting and fixing a cathode terminal 6 to a cathode layer of the capacitor element 2 through a conductive adhesive agent 4 so that a bottom side is exposed, and covering the whole capacitor element 2 with a resin by a transfer molding. A lead frame provided by windows plated beforehand is used for the cathode and anode terminals 5, 6, and the plated faces are introduced out on a part of the anode terminal 5 and the cathode terminal 6 led out from the side of the product in the chip type capacitor with its outside dimension cut to the desired dimension by a dicing processing or the like. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a chip-type capacitor having a resin outer structure, a manufacturing method thereof, and a lead frame used in the capacitor.
[0002]
[Prior art]
3 to 5 show examples of conventional chip capacitors. In this chip-type capacitor, 2 is a capacitor element, and the capacitor element 2 is formed by sintering and molding a powder made of a valve metal having an anode lead wire 3 embedded therein so as to expose one end. And a dielectric oxide film is formed on the anode body by a known method, and an electrolyte layer and a cathode layer (not shown) are sequentially formed on the surface.
[0003]
Further, the anode lead wire 3 exposed from the capacitor element 2 is connected to the anode terminal 5. That is, the anode terminal 5 is configured by connecting to an upright portion 19 disposed perpendicular to the bottom surface portion exposed on the mounting surface 9 side of the exterior resin 1 by a known method such as laser welding. Further, the cathode terminal 6 is configured by connecting and fixing to the cathode layer of the capacitor element 2 via the conductive adhesive 4 so that the mounting surface 9 side is exposed.
[0004]
Next, after the exterior resin 1 is formed by transfer molding so as to cover the connection portion with these terminals and the entire capacitor element 2 (FIG. 4), it is cut into a desired outer dimension by, for example, dicing (FIG. 5). ) A chip type capacitor is formed.
[0005]
Since the chip type capacitor has a simple connection structure between the capacitor element 2 and the anode terminal 5 and the cathode terminal 6, the storage volume efficiency of the capacitor element 2 with respect to the exterior resin 1 can be improved. This greatly contributes to the progress of miniaturization, large capacity and thinning of chip capacitors, which are required for further miniaturization of devices.
[0006]
However, in the conventional chip type capacitor described above, the plating on the terminal cut surface 14 is secured in order to ensure that the solder 11 is wetted (hereinafter referred to as fillet) to the terminal cut surface 14 on the product side surface when mounted on the substrate 10. Processing has to be carried out and has the following problems.
(1) The manufacturing cost increases due to the plating process.
(2) The number of manufacturing days (lead time) is increased by performing the plating process.
(3) In the case of a series of plating processes such as degreasing, plating, cleaning, and rust prevention, if liquid enters the exterior resin 1, the electrical characteristics and reliability of the product deteriorate.
[0007]
However, in mounting a chip capacitor, it is generally mounted on a land 12 formed on the substrate 10 and then soldered by reflow soldering. There is a problem that a phenomenon that the terminal is lifted from the substrate 10 and becomes vertical (also called a Manhattan phenomenon or a tombstone phenomenon) is likely to occur. In particular, since such a phenomenon is likely to occur in a small and light microchip, it is indispensable to form a fillet that improves the stabilization of the mounting posture.
[0008]
Therefore, in order to solve the above problem, the following method is disclosed as means for forming a fillet without performing a plating process after cutting the terminal.
[0009]
(1) In Patent Document 1, as shown in FIG. 6, a terminal bent portion 17 is disposed in a part of the anode terminal 5 and the cathode terminal 6, and solder is provided in a space portion below the terminal bent portion 17. A method of forming a fillet by entering 11 is described.
[0010]
(2) In Patent Document 2, as shown in FIG. 7, a part of the anode terminal 5 and the cathode terminal 6 is raised, and a fillet is formed on the terminal rising part 18 exposed on the outer surface of the exterior resin. A method is described.
[0011]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-291642 [Patent Document 2]
Japanese Patent Laid-Open No. 2002-043175
[Problems to be solved by the invention]
However, the chip capacitors described in Patent Document 1 and Patent Document 2 have the following drawbacks.
[0013]
(1) Since a minute bending process is performed on a part of the terminal, a complicated process must be performed on the lead frame (band metal plate) in advance, resulting in an increase in manufacturing cost.
[0014]
(2) The surface of the terminal bending part and the terminal rising part are not sandwiched and pressed between the upper mold and the lower mold, so that resin can easily enter and adhere to the terminal surface. This contributes to preventing fillet formation.
[0015]
(3) In order to prevent the resin adhesion described in (2) above, it is necessary to add a manufacturing process such as attaching a masking tape to the terminal or performing a honing finish after molding, which increases the manufacturing cost. Become.
[0016]
(4) After the mounting, the fillet is formed in a state of being embedded inside the outer shape of the product, so the visibility from above is poor, especially when the product is mounted on the substrate at a high density, Inspection becomes difficult.
[0017]
Therefore, in the present invention, a chip capacitor, a manufacturing method thereof, and a lead frame used for the capacitor can be formed without adding a manufacturing process such as masking or honing, which is essential for stabilizing the mounting posture of the product. It is intended to provide.
[0018]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention is characterized in that a pre-plated window is provided in a part of a lead frame used in the capacitor when a chip capacitor is manufactured.
[0019]
That is, the present invention forms a porous anode body by molding and sintering a powder made of a valve action metal having an anode lead wire embedded so that one end is exposed, a dielectric oxide film on the anode body, A capacitor element formed by sequentially forming an electrolyte layer and a cathode layer, and a bottom surface portion with one end exposed on the mounting surface side of the exterior resin, and the other end disposed perpendicular to the bottom surface portion An anode terminal welded to intersect the anode lead wire exposed from the capacitor element, and a cathode connected and fixed to the cathode layer of the capacitor element via a conductive adhesive so that the bottom surface side is exposed An anode led out to the side of a product in a chip type capacitor in which a terminal is resin-coated by transfer molding so as to cover the entire capacitor element and then cut into a desired outer dimension by dicing or the like A chip capacitor, wherein a surface plated part has been subjected in the child and the cathode terminal are led.
[0020]
In addition, the present invention is a chip capacitor, wherein the plated surface lead-out portion is disposed at one or more locations on one side of the product side surface.
[0021]
Further, the present invention provides the chip capacitor, wherein a width dimension of one side of the exposed portion of the plated surface is 1/2 or more of a product side surface width dimension.
[0022]
In addition, the present invention is a lead frame for a chip-type capacitor, wherein windows of various shapes such as a square, a triangle, and a trapezoid are formed with a cross-section plated in advance as one surface.
[0023]
The present invention is the lead frame for a chip capacitor, wherein the plated surface is substantially collinear with one side surface of the chip capacitor.
[0024]
Furthermore, the present invention forms a porous anode body by molding and sintering a powder made of a valve action metal having an anode lead wire embedded so that one end is exposed, a dielectric oxide film on the anode body, Capacitor element formed by sequentially forming an electrolyte layer and a cathode layer, and a bottom end with one end exposed to the mounting surface side of the exterior resin, and a tip with the other end disposed perpendicular to the bottom surface An anode terminal welded so as to cross the anode lead wire exposed from the capacitor element, and a cathode terminal connected and fixed to the cathode layer of the capacitor element via a conductive adhesive so that the bottom surface side is exposed, In a manufacturing method of a chip-type capacitor in which a resin is coated by transfer molding so as to cover the entire capacitor element and then cut into a desired outer dimension by dicing or the like, the lead frame as described above is positively bonded A method of manufacturing a chip-type capacitor, characterized in that it is used for a terminal and a cathode terminal, and the anode terminal and the cathode terminal are cut along the plating surface while leaving the plating surface, and the product is made into pieces of a predetermined shape. .
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings.
[0026]
FIG. 1 is a perspective view of an embodiment of a chip-type capacitor according to the present invention. In FIG. 1, 1 is an exterior resin, 5 and 6 are an anode terminal and a cathode terminal in which a lead frame having a uniform thickness, which has been previously plated with solder, is exposed on the bottom surface of the exterior resin 1, and 14 is an exterior. Cut surfaces 8 and 8 of the negative anode terminals 5 and 6 led out on both side surfaces of the resin 1 are plating led out on both side surfaces of the exterior resin 1.
[0027]
Further, an embodiment of the present invention will be described in detail with reference to FIGS. 2 is a perspective view of the chip capacitor of the present invention shown in FIG. 1 after transfer molding. In the lead frame used in the chip type capacitor of the present invention, a rectangular window in which one surface is disposed on the same surface as the product side surface on the anode terminal 5 and the cathode terminal 6 and plated in advance on the surface. It has a structure that has been perforated.
[0028]
Thereafter, by using a known means such as dicing along the one surface, the chip type capacitor shown in FIG. 1 is completed by cutting so as to cross the anode terminal 5 and the cathode terminal 6.
[0029]
The chip type capacitor thus obtained has a structure in which a part of the side surface of the product plated with 8 is led out, and a fillet is formed by wetting of the solder 11 when mounted on the substrate 10. Is possible.
[0030]
It is desirable that the surface provided with the plating 8 led out to a part of the product side surface is 1/2 or more of the width dimension of the product side surface in order to further stabilize the mounting posture of the product.
[0031]
In the above embodiment, the window 7 has been described as having a quadrangular shape, but various shapes such as a triangle or a trapezoid can be employed.
[0032]
The chip capacitor of the present invention has the following advantages over the conventional chip capacitor.
[0033]
(1) In manufacturing the lead frame, unlike the conventional fine bending process, the fillet can be formed by a punching process (square shape), so that the manufacturing cost can be reduced.
[0034]
(2) When forming the exterior resin, pressurization is applied to the terminal surface near the surface of the terminal where the solder gets wet, so the manufacturing process such as masking tape application and honing finish after molding is added to the terminal surface. Can be surely prevented.
[0035]
(3) Since the fillet can be reliably viewed from above the product, inspection after mounting on the board becomes easy.
[0036]
【The invention's effect】
As described above, according to the present invention, in manufacturing a chip-type capacitor, the lead is disposed so that one surface is substantially flush with the side surface of the product, and the surface is previously plated with a window. By using a frame and resin coating, by cutting the terminal along the one surface, fillets can be formed by solder wetting, which is essential for stabilizing the mounting posture, and the following effects can be expected. .
(1) Since it is realizable without performing fine processing to a terminal or addition of a manufacturing process, manufacturing cost can be reduced.
(2) Since the fillet formation state can be confirmed from above the product, the appearance inspection after mounting can be easily performed.
[Brief description of the drawings]
FIG. 1 is a perspective view of a chip capacitor of the present invention.
FIG. 2 is a perspective view of the chip capacitor of the present invention after transfer molding.
FIG. 3 is a cross-sectional view of the present invention and a conventional chip capacitor when mounted on a substrate.
FIG. 4 is a perspective view after transfer molding of a conventional chip capacitor.
FIG. 5 is a perspective view of the conventional chip-type capacitor after cutting the negative anode terminal.
FIG. 6 is a cross-sectional view of a conventional chip capacitor when mounted on a substrate.
FIG. 7 is a cross-sectional view of a conventional chip capacitor when mounted on a substrate.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Exterior resin 2 Capacitor element 3 Anode lead wire 4 Conductive adhesive 5 Anode terminal 6 Cathode terminal 7 Window 8 Plating 9 Mounting surface 10 Board | substrate 11 Solder 12 Land 13 Surface tension 14 Terminal cut surface 17 Terminal bending part 18 Terminal rising part 19 Standing part

Claims (6)

Molding and sintering a powder made of a valve metal with an anode lead wire embedded so that one end is exposed to form a porous anode body. A dielectric oxide film, an electrolyte layer, and a cathode layer are formed on the anode body. Capacitor elements formed and formed in sequence, and a bottom surface portion whose one end is exposed to the mounting surface side of the exterior resin, and the other end is welded so as to intersect with the anode lead wire exposed from the capacitor element An anode terminal and a cathode terminal connected and fixed to the cathode layer of the capacitor element via a conductive adhesive so that the bottom surface side is exposed to the mounting surface side of the exterior resin so as to cover the entire capacitor element In a chip capacitor that has been coated with a resin by transfer molding and then cut to the desired outer dimensions by dicing or the like, plating is performed on part of the anode and cathode terminals led out to the side of the product. Chip capacitor, wherein a surface which is derived. 2. The chip capacitor according to claim 1, wherein the lead-out portion of the plated surface is disposed at one place or a plurality of places on one side surface of the product. 3. The chip capacitor according to claim 1, wherein a width dimension of one side of the exposed portion of the plated surface is ½ or more of a product side surface width dimension. A lead frame for a chip-type capacitor, wherein a window having a pre-plated cross section as one surface is perforated. The lead frame for a chip capacitor according to claim 4, wherein the plated surface is substantially flush with one side surface of the chip capacitor. A capacitor element, a bottom surface portion exposed to the mounting surface side of the exterior resin, and an anode terminal welded to the anode lead of the capacitor element at the other end; In a manufacturing method of a chip-type capacitor in which a cathode terminal connected and fixed so as to be exposed to the side is coated with a resin by transfer molding so as to cover the entire capacitor element, and then cut into a desired external dimension in advance. A lead frame having a window with a cross section applied as a surface is used for the anode terminal and the cathode terminal, and the cross section in which the plating is performed on a part of the anode terminal and the cathode terminal led out to the side of the product. A method of manufacturing a chip capacitor, wherein the lead frame is cut so as to be derived.

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