JP2002175952A - 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 external leads formed by cutting the lead frame are bent along the exterior to form a 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, external electrodes 05 ', 06' are provided on the lower surface of the capacitor, and the external electrodes 05 ', 06' and the anode lead wire 04 'of the capacitor element 02' are connected to a conductive auxiliary lead wire. One connected via 09 'is known.

[0006]

However, although the chip type solid electrolytic capacitor 01 'using the auxiliary lead wire 09' can improve the volume efficiency as compared with the conventional one, the ratio of the elements occupied by the element is large. If the capacitor element is not correctly mounted in the specified position when mounted,
When a capacitor is cut out, there is a problem in that the capacitor is cut or the thickness of the resin covering the capacitor element becomes extremely thin.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a capacitor lead frame capable of reducing defects due to positional displacement by improving the positional accuracy of the capacitor element. And

[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 capacitor lead frame for mounting a capacitor element having the anode lead-out line led out by the anode body at a substantially central portion of a side surface thereof, and a concave portion formed between the convex portion and the convex portion. The projection is formed such that the bottom surface dimension is equal to or slightly wider than the bottom surface width dimension of the capacitor element. According to this feature, by having the convex portion, the bottom dimension of the concave portion formed by the convex portion is substantially equal to the dimension of the capacitor element. Not only the positioning becomes easy, but also the movement of the capacitor element is restricted, so that the position of the capacitor element can be securely held at the time of mounting the capacitor element. Can be reduced to

[0009] The lead frame for a capacitor of the present invention comprises:
It is preferable that the shape of the projection has a projection corresponding to the height of the lower end of the anode lead wire from the lower surface of the mounted capacitor element. By doing so, it is not necessary to attach an auxiliary lead wire as in the related art, so that the step of attaching the auxiliary lead wire can be eliminated and the internal structure of the obtained capacitor can be simplified.

[0010] The lead frame for a capacitor of the present invention comprises:
It is preferable that a protrusion is provided at a predetermined position of the projection to hold the anode lead-out line. With this configuration, the anode lead-out line is held at the fitting portion when the capacitor element is mounted, so that not only can the capacitor element be easily positioned but also the movement of the anode lead-out line is restricted. Position shift can be suppressed.

[0011] The lead frame for a capacitor of the present invention comprises:
It is preferable that the fitting portion is formed by two protrusions provided at predetermined positions straddling the anode lead-out line.
With this configuration, not only can the fitting portion be easily formed, but also the projection serves as a connection portion with the anode lead-out line, so that these connection portions can be specified.

[0012] The lead frame for a capacitor of the present invention comprises:
The shape or position of the shape of the convex portion or the formation position of the projecting portion is such that the connecting portion between the convex portion and the anode lead wire is closer to the capacitor element than the cut surface in cutting out to be a capacitor. It is preferable that 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.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a perspective view showing a structure of a chip type solid electrolytic capacitor using a lead frame of the embodiment 1, and FIG. 2 is a chip using the lead frame of the embodiment 1. FIG. 3 is a cross-sectional view showing a solid electrolytic capacitor of the type, FIG. 3 is a view showing the shape of a lead frame used in the first embodiment, and FIG. 4 is an external perspective view of the lead frame used in the first embodiment. is there.

As shown in FIG. 1, a chip-type solid electrolytic capacitor 1 according to a first embodiment has a capacitor element 2 and an anode lead wire 4 led out from one side of the capacitor element 2, which is welded to the upper end face. 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, an element which has been conventionally used as a solid electrolytic capacitor element, for example, anodized surface of a sintered body obtained by molding and sintering a valve metal powder such as tantalum. A capacitor element or the like 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 according to the first embodiment will be described along with its manufacturing process. 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 protrusions 19 are formed on the upper surface of the protrusion 20 on the side of the cut groove 16 on the side where the capacitor element is mounted.
The anode lead-out wire 4 led out of the capacitor element 2 is formed at a predetermined interval so as to be fitted therein so that the anode lead-out wire 4 can be locked and disposed.

The formation of the two projections 19 at a predetermined interval in this manner not only facilitates the 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 positional deviation 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 bottom dimension of the recess formed between the projections 20 is equal to or slightly wider than the bottom width of the capacitor element 2. Since the positioning of the capacitor element 2 is facilitated and the movement of the capacitor element 2 is restricted, the position of the capacitor element 2 can be reliably held, and the chip-type solid electrolytic capacitor 1 It can be cut out in a state.

First, as shown in FIG. 5A, a conductive adhesive 10 is applied on the upper surface of the portion of the lead frame 11 which will be the cathode terminal 6, and after the application, as shown in FIG. 5B. Is mounted with the capacitor element 2.

At this time, the protrusions 20 of the lead frame 11
Since the bottom dimension of the concave portion formed between the capacitor element 2 and the bottom is substantially equal to the bottom width dimension of the capacitor element 2, the capacitor element 2 can be securely held at a predetermined position. In addition, defects at the time of cutting can be reduced.

The anode lead-out wire 4 is locked and held by placing the anode lead-out wire 4 between the projections 19, 19 formed in the vicinity of the capacitor element 2 of the projection 20. The positioning of the capacitor element 2 can be easily performed, the lateral movement of the capacitor element 2 can be restricted, and the connecting portion between the convex portion 20 and the anode lead-out wire 4 can be connected to the projecting portion 19. Therefore, it is possible to prevent the connection between the protrusion 20 and the connection portion of the anode lead wire 4 from becoming unstable during the cutting operation performed during the molding of the capacitor.

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 is formed by using an ink jet nozzle (not shown) so that the thickness of the conductive adhesive 10 is sufficient at the corresponding portion of the lead frame 11. Although the conductive adhesive 10 is formed by applying the conductive adhesive 10, the present invention is not limited to this, and any method can be used for forming the conductive adhesive 10.

In the application by the ink jet nozzle, the application is repeated a plurality of times so that a good conductive adhesive without pinholes 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, particularly the heat shrinkage is small, and the pressure-sensitive adhesive tape also functions as a sealing resin weir described later. 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 polyimide tape 12 has been applied, the sealing resin which becomes 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 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 during board mounting. 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 appropriately 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. 6F together with the exterior resin 3 that has entered the recesses 13, 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.

(Embodiment 2) FIG. 7 is a view showing a chip type solid electrolytic capacitor 1 'according to Embodiment 2 of the present invention.
As a feature, in place of the anode terminal 5 of the first embodiment,
As shown in FIG. 7, 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 convex portion in the first embodiment is such that the apex is located near the capacitor element 2 so that the convex portion in 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 gist of the present invention. Needless to say, this is included in the present invention.

In the first embodiment, a fitting portion 21 may be provided on the upper surface of the convex portion 20 on the side on which the capacitor element is mounted as shown in FIG. 21 makes it easier not only to position the capacitor element 2 described later, but also to lock the lower part of the anode lead wire 4 and the fitting portion 21 so that the anode lead wire 4 can be fixed. Although it is preferable because displacement can be prevented, the present invention is not limited to this. Further, at a place where the lower part of the anode lead-out wire 4 of the fitting part 21 comes into contact, the width of a part of the fitting part on the side on which the capacitor element 2 is mounted is reduced, so that the anode lead-out wire 4 is locked and secured. The anode lead wire 4 and the lead frame 11 can be securely welded to each other, and the welded portion is located close to the capacitor element 2. It is possible to prevent the connection with the connection portion with the anode lead wire from becoming unstable.

[0041]

The present invention has the following effects.

(A) According to the first aspect of the present invention, since the protrusion has the protrusion, the bottom dimension of the recess formed by the protrusion is substantially equal to the dimension of the capacitor element. At the time of mounting the element, not only is the positioning of the capacitor element easy, but also the movement of the capacitor element is restricted, so that the position of the capacitor element can be reliably held at the time of mounting the capacitor element, Defects at the time of cutting due to displacement can be significantly reduced.

(B) According to the second aspect of the present invention, it is not necessary to provide an auxiliary lead wire as in the prior art, so that the step of attaching the auxiliary lead wire can be eliminated and the internal structure of the obtained capacitor can be simplified. Can be

(C) According to the third aspect of the present invention, the anode lead-out line is held at the fitting portion when the capacitor element is mounted, so that not only the positioning of the capacitor element can be easily performed but also the anode lead-out. The displacement can be suppressed by restricting the movement of the line.

(D) According to the fourth aspect of the present invention, not only can the fitting portion be easily formed, but the projection serves as a connection portion with the anode lead-out wire, so that these connection portions can be specified.

(E) According to the fifth aspect of the present invention, it is possible to prevent the connection between the convex portion and the connecting portion between the anode lead wire from becoming unstable due to the cutout for forming the capacitor.

[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.

FIG. 11 is an external perspective view in a case where a fitting portion is provided in a protrusion of a lead frame used in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip-type solid electrolytic capacitor 1 'Chip-type solid electrolytic capacitor 2 Capacitor element 3 Exterior 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 21 Fitting part

Claims (5)

[Claims] 1. A capacitor element having a dielectric oxide film, an electrolyte layer, and a cathode layer sequentially laminated on a surface of an anode body made of a valve metal and mounting an anode lead wire led by the anode body is mounted. A lead frame for a capacitor, wherein the convex portion is formed such that a bottom surface size of a concave portion formed between the convex portion and the convex portion is equal to or slightly wider than a bottom surface width of the capacitor element. Characteristic lead frame for capacitors. 2. The capacitor lead frame according to claim 1, wherein the height of the projection is formed so as to correspond to the height of the lower end of the anode lead wire from the lower surface of the mounted capacitor element. 3. The capacitor lead frame according to claim 2, wherein a fitting portion capable of holding the anode lead wire is formed at a predetermined position of the convex portion. 4. The capacitor lead frame according to claim 3, wherein the fitting portion is formed by two protrusions provided at predetermined positions across the anode lead-out line. 5. The shape of the projection or the formation position of the projection, wherein the connection between the projection and the anode lead-out line is located closer to the capacitor element than a cut surface in the cutout for forming a capacitor. The lead frame for a capacitor according to any one of claims 2 to 4, wherein the lead frame has a shape or a position.