JP2002175953A - Lead frame for capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To settle the step of attaching an auxiliary lead wire of prior art and to settle the problem of turning into complexity of the internal structure of a resultant capacitor. SOLUTION: In a capacitor lead frame 11 for mounting a capacitor element 2, which is made of a laminate of a dielectric oxide film, an electrolyte layer and a cathode layer sequentially laminated on an anode of valve action metal and wherein an anode lead wire 4 led from the anode is positioned nearly at the center of its side surface; and the capacitor element 2 is provided on its lower surface with a projection 20, corresponding to the height of a lower end of the anode lead wire 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor mounted on various electronic devices, and particularly to a lead frame used for a chip type solid electrolytic capacitor which can be used for high-density surface mounting.

[0002]

2. Description of the Related Art As a conventionally known chip type solid electrolytic capacitor, for example, FIG.
No. 8942. This chip-type solid electrolytic capacitor 01 forms an oxide film serving as a dielectric by anodic oxidation on the surface of a sintered body obtained by molding and sintering a valve metal powder such as tantalum to form an anode body, A capacitor element 02 obtained by laminating a solid electrolyte layer such as manganese dioxide and a cathode layer made of carbon or silver paste on the anode body and attaching the capacitor element 02 to a lead frame having an anode lead 05 and a cathode lead 06. It has been.

The lead frame used for these chip-type solid electrolytic capacitors 01 is disclosed in, for example, Japanese Utility Model Laid-Open No. 62-89.
No. 126 has a structure as shown in FIG. 5 or FIG. 6, in which an anode lead wire 04 derived from a capacitor element is welded to an anode lead frame 05 and the cathode layer is provided on the outer periphery thereof. After bonding the main body of No. 02 to the cathode lead frame 06 with solder or the like,
The capacitor element 02 is resin-sealed by transfer molding with an epoxy resin 03 or the like, and the external leads formed by cutting the lead frame 06 are bent along the exterior to form the chip-type solid electrolytic capacitor 01.

[0004] However, such a chip-type solid electrolytic capacitor 01 has an anode lead wire 04 and an anode lead 05.
Is welded to the resin 03, so that the volume occupied by the capacitor element 02 with respect to the entire size of the capacitor is small, which is sufficient for a demand for a small and large-capacity capacitor. It was not something we could handle.

[0005] For this reason, FIG.
As shown in No. 1, the external electrodes 05 'and 06' are provided on the lower surface of the capacitor, and the external electrodes 05 'and 06' and the anode lead wire 04 'of the capacitor element 02' are connected to a conductive pillow member 09. What is connected via 'is known.

[0006]

However, the chip-type solid electrolytic capacitor 01 'using the pillow member 09' as an auxiliary lead wire can improve the volumetric efficiency as compared with the conventional one, but the auxiliary pillow member 09 'has the following advantages. In order to use the lead wires, a step of joining these auxiliary lead wires to the lead frame is necessary, and in this step, it is necessary to perform processing such as positioning and welding of these auxiliary lead wires,
There is a problem that these steps are complicated and the internal structure of the obtained capacitor is complicated.

Accordingly, the present invention has been made in view of the above-mentioned problems, and can eliminate the step of attaching the auxiliary lead wires and can also prevent the internal structure of the obtained capacitor from becoming complicated. It is an object of the present invention to provide a capacitor lead frame that can be used.

[0008]

In order to solve the above-mentioned problem, a lead frame for a capacitor according to the present invention is provided with a dielectric oxide film, an electrolyte layer, and a cathode layer on a surface of an anode body made of a valve metal. A laminate lead frame for mounting a capacitor element having an anode lead wire led by the anode body at a substantially central portion of a side surface thereof, wherein the lead wire for the anode lead wire extends from a lower surface of the mounted capacitor element. It is characterized by having a projection corresponding to the lower end height. According to this feature, the provision of the convex portion eliminates the necessity of providing an auxiliary lead wire as in the related art, not only eliminating the process of attaching the auxiliary lead wire, but also complicating the internal structure of the obtained capacitor. Can be eliminated.

[0009] The lead frame for a capacitor of the present invention comprises:
It is preferable that the shape of the protrusion is such that the connection between the upper end of the protrusion and the anode lead-out line is closer to the capacitor element than the cut surface of the cutout for forming the capacitor. With this configuration, it is possible to prevent the connection between the protrusion and the connection portion between the anode lead wire from becoming unstable due to the cutout for forming the capacitor.

[0010] The lead frame for a capacitor of the present invention comprises:
It is preferable that a projection is provided at a predetermined position on the upper surface of the projection, which is closer to the capacitor element than a cut surface in the cutout for forming a capacitor. With this configuration, since the connecting portion between the convex portion and the anode lead-out line becomes the projecting portion, the cut-out for forming the capacitor allows the connecting portion between the convex portion and the anode lead-out line to be formed. The connection can be prevented from becoming unstable.

[0011] The lead frame for a capacitor of the present invention comprises:
It is preferable that two protrusions are provided at positions that straddle the anode lead-out line so as to restrict the lateral movement of the anode lead-out line and to locate the protrusion. With this configuration, the anode lead wire is locked and held between the protrusions when the capacitor element is mounted, so that the positioning and fixing of the capacitor element can be performed more easily.

[0012] The lead frame for a capacitor of the present invention comprises:
It is preferable that a plurality of columns on which the plurality of capacitor elements are mounted are provided in parallel. In this way, the number of cuts (dicing) can be reduced.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a perspective view showing the structure of a chip-type solid electrolytic capacitor of Embodiment 1 and FIG.
FIG. 3 is a cross-sectional view showing the chip-type solid electrolytic capacitor of FIG. 1, FIG. 3 is a view showing the shape of the lead frame used in the first embodiment, and FIG. 4 is an external perspective view of the lead frame used in the first embodiment. FIG.

As shown in FIG. 1, the chip type solid electrolytic capacitor 1 of the first embodiment has a capacitor element 2 and an anode lead wire 4 led out from one side surface of the capacitor element 2 welded to the upper end face thereof. An anode terminal 5 having an L-shaped cross section when connected to the anode terminal 5, and disposed below the capacitor element 2 on a side facing the anode terminal 5 with the capacitor element 2 interposed therebetween; The capacitor element 2 is covered with the cathode terminal 6 electrically and mechanically joined to the lower surface of the outer peripheral portion of the element 2 with the conductive adhesive 10 and a portion excluding the anode terminal 5 and the cathode terminal 6 exposed portion. And an exterior resin 3 that covers the battery.

The anode terminal 5 used in the first embodiment
Has an L-shape in cross section as described above, and is provided such that the inner surface side of the L shape is along the lower surface of the capacitor element 2 and the side surface from which the anode lead wire 4 is led.

As the capacitor element 2, anodization is performed on the surface of a sintered body obtained by molding and sintering a valve metal powder such as tantalum, which has been conventionally used as a solid electrolytic capacitor element. A capacitor element or the like is obtained by forming an oxide film that becomes a dielectric by using an anode body, and laminating a solid electrolyte layer such as manganese dioxide and a cathode layer made of carbon or silver paste on the anode body. It can be suitably used. still,
As the solid electrolyte, those using a polymer electrolyte such as polypyrrole can also be used.

Hereinafter, the chip type solid electrolytic capacitor 1 of the first embodiment will be described along with its manufacturing steps. First, in the first embodiment, the anode terminal 5 and the cathode terminal 6 are
4, and is formed by a lead frame 11 on which a plurality of capacitor elements 2 can be mounted. The lead frame 11 has a bent portion shown in FIG. As a result, a convex portion 20 as shown in FIG. 4 is formed.

As shown in FIG. 4, two projections 19 are formed on the upper surface of the projection 20 on the side of the cutting groove 16 to be described later on the side where the capacitor element is mounted.
The anode lead wire 4 led out of the capacitor element 2 is formed at a predetermined interval so that the lead wire 4 can be locked and disposed therebetween.

The formation of the two projections 19 at a predetermined interval in this manner not only facilitates positioning of the capacitor element 2 during mounting of the capacitor element 2 described later, but also facilitates the positioning of the anode lead wire 4. Locking the lower portion and the projections 19 is preferable because the displacement of the anode lead wire 4 is prevented, but the present invention is not limited to this. As shown in FIG.
Only one may be formed.

The lead frame 11 of this embodiment is
The mounting rows of the capacitor elements 2 are formed in two rows in parallel, and this arrangement allows one-way dicing to be performed in common by adjacent capacitors in dicing to be described later. Although it is preferable because the number of times can be reduced, the present invention is not limited to this, and the number of these rows may be further increased, or conversely, a single row may be used. Good.

First, as shown in FIG. 5 (a), a conductive adhesive 10 is applied and formed on the upper surface of the portion to be the cathode terminal 6 of the lead frame 11, and after the application, as shown in FIG. 5 (b). The capacitor element 2 is mounted as described above.

As the conductive adhesive 10, since the cathode layer made of carbon or silver paste is exposed on the lower surface of the capacitor element 2 to be connected as described above,
From the viewpoint of the adhesion to the cathode layer and the like, the I
The silver-based conductive adhesive 10 used for the mount of C or the like is preferably used, but the present invention is not limited to this, and a solder paste or the like is applied instead of the conductive adhesive 10. In advance, after mounting the capacitor element 2, the solder paste is melted to fix the capacitor element 2,
You may implement it.

In the first embodiment, the conductive adhesive 10
In the method of (1), a conductive adhesive 10
Is formed by applying the conductive adhesive 10 so that the thickness of the conductive adhesive 10 is sufficient, but the present invention is not limited to this, and any method can be used for forming the conductive adhesive 10. Can be used.

In the application by the ink-jet nozzle, the application is repeatedly performed a plurality of times so that a good conductive adhesive having no pinhole can be formed.

In mounting these capacitor elements 2,
The anode lead wire 4 and the projection 19 are welded and connected by electric welding, and the conductive adhesive 10 is dried or cured to fix the capacitor element 2.

Next, as shown in FIG. 5C, the lead frame 11 on which the capacitor element 2 is fixed and mounted is mounted.
A polyimide tape 12 as an adhesive tape is adhered from the lower surface side of the lead frame 11 so as to cover the lower surface.
Masking of the lower surface of is performed.

In Example 1, the heat resistance of the pressure-sensitive adhesive tape, in particular, low heat shrinkage, and the pressure-sensitive adhesive tape also acts as a sealing resin weir described later, so that the sealing resin has barrier properties and mechanical strength. From the viewpoint of using a polyimide tape having a silicone pressure-sensitive adhesive layer formed on one surface of the polyimide film as described above, the silicone pressure-sensitive adhesive layer also functions as a release agent layer with the sealing resin. However, the pressure-sensitive adhesive tape of the present invention is not limited to the polyimide tape, and any of these pressure-sensitive adhesive tapes may be appropriately selected and used from the viewpoint of heat resistance, cost, and the like.

After the application of the polyimide tape 12, the sealing resin to be the exterior resin 3 is applied to the entire lead frame 11 and the entire capacitor element 2 is applied to the exterior resin 3 as shown in FIG. The lead frame 11 is poured so as to have a predetermined thickness so as to be covered.
After the exterior resin 3 is filled to a minute area inside by making the external atmosphere vacuum, the exterior resin 3
To cure.

As described above, it is preferable to make the external atmosphere a vacuum, since it becomes possible to quickly fill the interior resin into the minute area inside, but the present invention is not limited to this.

As the exterior resin 3, an epoxy resin such as epoxy acrylate, which is a molding resin used in the conventional transfer molding, can be suitably used, and a heat resistant material capable of withstanding soldering heat at the time of mounting the substrate. Any resin having properties and capable of obtaining a liquid state at an appropriate heating state or normal temperature can be suitably used.

After the exterior resin 3 has been properly cured, as shown in FIG. 6E, the polyimide tape 12 is peeled off, and then the rear recess 13 of the projection 20 of the lead frame 11 is removed. By performing a rounding process so that the corners of the lead frame 11 are curved as shown in FIG. 6 (f) together with the exterior resin 3 having entered the recesses 13, the anode terminal 5 and the anode terminal 5 shown in FIG. The solder receiving portions 7 and 8 of the cathode terminal 6 are formed.

The formation of the solder receiving portions 7 and 8 in this manner allows a sufficient contact area with solder to be obtained when the obtained chip-type solid electrolytic capacitor 1 is mounted on a substrate. The present invention is preferable because not only the mounting strength can be obtained, but also the area of the solder fillet exposed on the outer periphery of the chip-type solid electrolytic capacitor 1 can be significantly reduced, and the mounting efficiency can be improved. It is not limited to this.

After performing these R processing, FIG.
As shown in (g), after the exposed portion of the lead frame 11 is plated with a metal such as the solder plating 14 which can improve the wettability with solder, the chip-type solid electrolytic capacitor 1 is formed.
As shown in FIG. 6 (h), a dicing tape 1 is provided on a surface opposite to the exposed surface of the lead frame 11 corresponding to the upper surface of the dicing tape 1.
5 as shown in FIG. 6 (i).
A cutting groove 16 is formed from the side, and the cutting area in FIG. 3 is cut out to obtain the chip-type solid electrolytic capacitor 1. (Example 2)

FIG. 7 is a view showing a chip type solid electrolytic capacitor 1 'of the second embodiment. The feature of the second embodiment is that the anode terminal 5 of the first embodiment is replaced with that of FIG. A lead frame 11 'having an anode terminal 5' having a convex upper end is used.

In this way, as shown in FIG. 7, the shape of the projection in the first embodiment is such that the apex is located on the side near the capacitor element 2 so that FIG.
As shown in (b), even when a chip-type solid electrolytic capacitor is cut out, the connection between the anode terminal 5 'and the anode lead wire 4 is located inside the capacitor, and the electrical connection is reliably maintained. Become so.

Although the present invention has been described with reference to the drawings, the present invention is not limited to the above-described embodiments, and changes and additions may be made without departing from the spirit of the present invention. Needless to say, this is included in the present invention.

For example, in the above embodiment, the convex portion 20 is formed by bending, but the present invention is not limited to this, and the 42 alloy rolled plate to be the lead frame 11 is used. In advance, a thick portion is formed in advance in a rolling step, and the lead frame 11 is molded and punched by press working so that the thick portion becomes the convex portion 20, as shown in FIG. 4 inside the projection 20
2 alloy may be filled. By doing so, the bending process in the above embodiment can be omitted to simplify the manufacturing process and further improve the mechanical strength of the lead frame. May be.

[0038]

The present invention has the following effects. (A) According to the first aspect of the present invention, the provision of the convex portion eliminates the need for attaching an auxiliary lead wire as in the related art.
Not only can the step of attaching the auxiliary lead wire be eliminated, but also the complicated internal structure of the obtained capacitor can be eliminated.

(B) According to the second aspect of the present invention, it is possible to prevent the connection between the projection and the anode lead wire from becoming unstable due to the cutout for forming the capacitor.

(C) According to the third aspect of the present invention, since the connecting portion between the convex portion and the anode lead-out line becomes the projecting portion, the convex portion and the anode are cut out to form the capacitor. It is possible to prevent the connection with the connection portion with the anode lead wire from becoming unstable.

(C) According to the fourth aspect of the present invention, when mounting the capacitor element, the anode lead wire is locked and held between the projections, so that the positioning and fixing of the capacitor element are more simplified. Can be implemented.

(C) According to the invention of claim 5, the number of cutting (dicing) can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a structure of a chip-type solid electrolytic capacitor according to Embodiment 1 of the present invention.

FIG. 2 is a cross-sectional view illustrating a chip-type solid electrolytic capacitor according to Embodiment 1 of the present invention.

FIG. 3 is a view showing a shape of a lead frame used in Embodiment 1 of the present invention.

FIG. 4 is an external perspective view of a lead frame used in the first embodiment of the present invention.

FIG. 5 is a view showing a manufacturing process of the chip-type solid electrolytic capacitor of the present invention.

FIG. 6 is a diagram showing a manufacturing process of the chip-type solid electrolytic capacitor of the present invention.

FIG. 7 is a cross-sectional view illustrating a chip-type solid electrolytic capacitor according to Embodiment 2 of the present invention.

FIG. 8 is an external perspective view showing another form of a lead frame.

FIG. 9 is a sectional view showing a conventional chip-type solid electrolytic capacitor.

FIG. 10 is a sectional view showing a conventional chip-type solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip-type solid electrolytic capacitor 1 'Chip-type solid electrolytic capacitor 2 Capacitor element 3 Outer resin 4 Anode lead-out line 5 Anode terminal 5' Anode terminal 6 Cathode terminal 7 Solder accommodation part (anode) 8 Solder accommodation part (cathode) 10 Conductivity Adhesive 11 Lead frame 11 'Lead frame 12 Polyimide tape 13 Depression 14 Solder plating 15 Dicing tape 16 Cutting groove 19 Projection 19' Projection 20 Projection

Claims (5)

[Claims] 1. An anode body made of a valve metal, a dielectric oxide film, an electrolyte layer and a cathode layer are sequentially formed on the surface of the anode body. What is claimed is: 1. A lead frame for a capacitor on which a capacitor element is mounted, comprising: a protrusion corresponding to a height of a lower end of the anode lead wire from a lower surface of the mounted capacitor element. 2. The shape of the projection is such that a connection between the upper end of the projection and the anode lead-out line is closer to the capacitor element than a cut surface of the cutout for forming a capacitor. Item 2. A lead frame for a capacitor according to Item 1. 3. The capacitor lead frame according to claim 1, further comprising a projection at a predetermined position on the upper surface of the projection, which is located closer to the capacitor element than a cut surface in the cutting for forming a capacitor. 4. The lead frame for a capacitor according to claim 3, wherein said projection has two protrusions at a position straddling said anode lead-out line so as to restrict lateral movement of said anode lead-out line and to position said protrusion. . 5. The capacitor lead frame according to claim 1, wherein a plurality of rows on which the plurality of capacitor elements are mounted are provided in parallel.