JP2002170741A - Method for manufacturing chip-type solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make manufacturing facility small in size and provide many kinds of chip-type solid electrolytic capacitor through simplified steps. SOLUTION: This method for manufacturing a chip-type solid electrolytic capacitor includes at least a mounting step where a plurality of repetitive units having parts as anode terminal and cathode terminal are provided and a plurality of capacitor elements 2 are mounted to mountable lead frames 11, an adhering step where an adhesive tape 12 is adhered to the non-mounting surface of the capacitor element 2 of the lead frame 11 after the mounting step, a covering step where adjoining capacitor elements 2 that are mounted to the lead frame 11 adhered with the adhesive tape 12 are covered with an exterior facing resin 3 and a continuous body of capacitor is obtained, and a cutting step where the continuous body is cut into a desired shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a chip type solid electrolytic capacitor usable for high-density surface mounting mounted on various electronic devices.

[0002]

2. Description of the Related Art Conventionally known chip-type solid electrolytic capacitors include, for example, the one shown in 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, when the individual chip-type solid electrolytic capacitors are to be transfer-molded, as in the case of the conventional chip-type solid electrolytic capacitors 01, the transfer-molding gold is used for each individual capacitor element 02. There is a problem that a mold is required, so that not only the manufacturing apparatus becomes large-scale, but also the manufacturing cost of each product increases.

Accordingly, the present invention has been made in view of the above-mentioned problems, and it is possible to not only reduce the size of the manufacturing equipment but also to simplify the process without using a transfer mold as described above. It is an object of the present invention to provide a method of manufacturing a chip-type solid electrolytic capacitor capable of obtaining various kinds of chip-type solid electrolytic capacitors.

[0006]

In order to solve the above-mentioned problems, a method of manufacturing a chip-type solid electrolytic capacitor according to the present invention has an anode lead-out line and a dielectric material on a surface of an anode body made of a valve action metal. An oxide film, an electrolyte layer, and a cathode layer are sequentially formed and laminated, and a capacitor element having an outer periphery serving as the cathode layer, and an exterior resin covering the capacitor element are provided, and an anode lead wire of the capacitor element is provided. And a method for manufacturing a chip-type solid electrolytic capacitor formed by forming an anode terminal and a cathode terminal connected to the cathode layer such that a part of each terminal is exposed from the exterior resin, wherein the anode terminal and the cathode terminal are A mounting step of mounting a capacitor element on a lead frame having a plurality of repeating units each including A bonding step of bonding an adhesive tape to the non-mounting surface of the capacitor element of the frame, and forming a continuous capacitor by covering the adjacent capacitor element mounted on the lead frame to which the adhesive tape is bonded with the exterior resin. It is characterized by including at least a coating step of obtaining a body, and a cutting step of cutting the continuous body of the capacitor into a predetermined shape. According to this feature, the pressure-sensitive adhesive tape serves as a weir for the exterior resin, and also serves as a masking material for the exposed portions of the anode terminal and the cathode terminal that do not require resin coating. Not only does the mold need not be used, the manufacturing equipment can be reduced in size, but also a chip-type solid electrolytic capacitor of another type can be obtained by a simple process.

In the method for manufacturing a chip-type solid electrolytic capacitor of the present invention, it is preferable that the pressure-sensitive adhesive tape has heat resistance that does not cause significant thermal deformation even under heating conditions applied in the coating step. By doing so, the shape defect of the obtained chip-type solid electrolytic capacitor can be significantly reduced.

In the method for producing a chip-type solid electrolytic capacitor of the present invention, it is preferable that the base film of the pressure-sensitive adhesive tape is a polyimide film having a predetermined thickness. By doing so, the polyimide-based film has very high heat resistance and excellent mechanical strength, and thus is suitable as a base film for an adhesive tape.

In the method for manufacturing a chip-type solid electrolytic capacitor according to the present invention, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape may have heat resistance that does not cause a significant drop in adhesive force even under heating conditions applied in the coating step. preferable. With this configuration, it is possible to prevent the coating resin (exterior resin) from penetrating into an unnecessary portion and causing a defective product due to a decrease in the adhesive strength during the heating in the coating step.

In the method for manufacturing a chip-type solid electrolytic capacitor according to the present invention, it is preferable that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape has an appropriate release property without adhering to the exterior resin. This makes it possible not only to easily peel off the adhesive tape, but also to prevent the adhesive layer from being transferred to the exterior resin display and becoming a defective product.

In the method for manufacturing a chip-type solid electrolytic capacitor of the present invention, it is preferable that the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is formed of an organic silicon-based polymer pressure-sensitive adhesive. According to this configuration, the organosilicon-based polymer pressure-sensitive adhesive is not only excellent in maintaining the adhesive strength at high temperatures, but also has an appropriate release property, and thus is suitable as the pressure-sensitive adhesive for the pressure-sensitive adhesive tape.

In the method of manufacturing a chip-type solid electrolytic capacitor of the present invention, it is preferable that in the covering step, the external atmosphere of the lead frame is set to a predetermined low pressure state. By doing so, not only the coating resin (exterior resin) can be satisfactorily filled up to a fine portion such as a gap between the lead frame and the adhesive tape, but also the time required for these coating steps can be significantly reduced. can do.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment) FIG. 1 is a perspective view showing the structure of a chip-type solid electrolytic capacitor of this embodiment, FIG. 2 is a sectional view showing the chip-type solid electrolytic capacitor of this embodiment, and FIG.
FIG. 4 is a diagram showing a shape of a lead frame used in the present embodiment, and FIG. 4 is an external perspective view of the lead frame used in the present embodiment.

Chip type solid electrolytic capacitor 1 of the present embodiment
As shown in FIG. 1, the cross-sectional shape of the capacitor element 2 and the anode lead wire 4 led out from one side surface of the capacitor element 2 connected to the upper end face by welding is L-shaped. Anode terminal 5, anode terminal 5 and capacitor element 2
A cathode terminal 6 disposed below the capacitor element 2 and electrically and mechanically joined to the lower surface of the outer peripheral portion of the capacitor element 2 with a conductive adhesive 10 on the side opposite to It mainly comprises an exterior resin 3 that covers the portion excluding the exposed portions of the anode terminal 5 and the cathode terminal 6 so as to cover the capacitor element 2.

The anode terminal 5 used in this embodiment is
As described above, the cross-sectional shape is L-shaped, and the inner surface of the L-shape is provided 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 this embodiment will be described along with its manufacturing process. First, in this embodiment, the anode terminal 5 and the cathode terminal 6 are formed as shown in FIGS. 3 and 4 by a lead frame 11 on which a plurality of capacitor elements 2 can be mounted. The lead frame 11 is formed by bending the bent portion shown in FIG. 3 to form a convex portion 20 as shown in FIG. Is mounted such that the upper surface of the projection 20 and the lower end of the anode lead-out wire 4 come into contact with each other when mounted.

As shown in FIG. 5 (a), first, a conductive adhesive 10 is applied and formed on the upper surface of the portion of the lead frame 11 which will be the cathode terminal 6, and after the application, the conductive adhesive 10 is 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 this embodiment, the method of applying the conductive adhesive 10 is such that a sufficient thickness of the conductive adhesive 10 can be obtained at a corresponding portion of the lead frame 11 using an ink jet nozzle (not shown). Although the conductive adhesive 10 is applied to the substrate, the present invention is not limited to this, and any method can be used for forming the conductive adhesive 10.

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

In mounting these capacitor elements 2,
The anode lead wire 4 and the upper surface of the projection 20 are connected by welding, and the conductive adhesive 10 is dried or cured to fix the capacitor element 2.

Next, as shown in FIG. 5 (c), a polyimide tape 12 which is an adhesive tape is attached from the lower surface side of the lead frame 11 on which the capacitor element 2 is fixed and mounted so as to cover the lower surface. The lower surface of the lead frame 11 is masked.

In this embodiment, the heat resistance of these pressure-sensitive adhesive tapes, in particular, the heat shrinkage is small, and the pressure-sensitive adhesive tape also functions as a sealing resin weir described later. In view of this, as shown in FIG. 7, a polyimide tape 12 in which a silicone adhesive layer 18 which is an organosilicon polymer adhesive is formed on one surface of a polyimide film 17 is used. Can function 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. Even if the adhesive tape has sufficient heat resistance so that the adhesive tape is not significantly deformed even at the heating temperature in the coating step, for example, Various polyimide resin film Te,
For example, a film of a polyimide amide resin or a polyether imide can be suitably used, and a polyether ketone (PEE
K) resin film, polyparabanic acid resin film or polyphenylene sulfide (PPS) resin film,
Polyethylene terephthalate (PET) resin film, polybutylene terephthalate (PBT) resin film, polycarbonate (PC) resin film, polyarylate (PAR) resin film, and the like can also be used. What is necessary is just to select suitably from the heating temperature in the coating process of the resin 3, a cost, etc.

The present invention is not limited to the silicone pressure-sensitive adhesive layer 18, but any material can be used as long as the pressure-sensitive adhesive force at a sufficiently high temperature can be obtained.

After the polyimide tape 12 is 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 attached 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 a fine region 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 preferably used, and a heat resistance capable of withstanding soldering heat at the time of mounting the substrate. Any resin can be suitably used as long as it has properties and can obtain a liquid state at an appropriate heating state or normal temperature.

After the exterior resin 3 has been appropriately cured, as shown in FIG. 6E, after the polyimide tape 12 is peeled off, the back surface recess 13 of the protrusion 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.

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.

[0033]

The present invention has the following effects. (A) According to the first aspect of the present invention, the pressure-sensitive adhesive tape serves as a dam for the exterior resin and also serves as a masking material for the exposed portions of the anode terminal and the cathode terminal which do not require resin coating. Not only does it not require a mold for transfer molding every time, it can reduce the size of manufacturing equipment,
Other types of chip-type solid electrolytic capacitors can be obtained by simple steps.

(B) According to the second aspect of the invention, it is possible to significantly reduce the shape defect of the obtained chip type solid electrolytic capacitor.

(C) According to the third aspect of the invention, the polyimide-based film has very high heat resistance and excellent mechanical strength, and thus is suitable as a base film for an adhesive tape.

(D) According to the fourth aspect of the present invention, the adhesive force is reduced during the heating in the coating step, so that the coating resin (exterior resin) also enters unnecessary portions and becomes defective. Can be avoided.

(E) According to the invention of claim 5, not only can the peeling of the pressure-sensitive adhesive tape be easily performed, but also it is possible to prevent the pressure-sensitive adhesive layer from being transferred to the exterior resin display and becoming a defective product. it can.

(F) According to the invention of claim 6, since the organosilicon-based polymer pressure-sensitive adhesive is not only excellent in maintaining the adhesive force at a high temperature, but also has an appropriate release property, It is suitable as an adhesive.

(G) According to the invention of claim 7, the coating resin (exterior resin) can be satisfactorily filled even into a fine portion such as a gap between the lead frame and the adhesive tape. The time required for these coating steps can be significantly reduced.

[Brief description of the drawings]

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

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

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

FIG. 4 is an external perspective view of a lead frame used in this 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 view showing a polyimide tape used in this example.

FIG. 8 is a sectional view showing a conventional chip-type solid electrolytic capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chip-type solid electrolytic capacitor 2 Capacitor element 3 Outer resin 4 Anode lead wire 5 Anode terminal 6 Cathode terminal 7 Solder accommodating part (anode) 8 Solder accommodating part (cathode) 10 Conductive adhesive 11 Lead frame 12 Polyimide tape 13 Concave part 14 Solder plating 15 Dicing tape 16 Cutting groove 17 Polyimide film 18 Silicone adhesive layer 20 Convex part

Claims (7)

[Claims] 1. A capacitor having an anode lead wire, a dielectric oxide film, an electrolyte layer, and a cathode layer sequentially formed on the surface of an anode body made of a valve action metal, and the outer periphery of which is the cathode layer. Element, and an exterior resin for covering the capacitor element, wherein the anode lead and the anode terminal and the cathode terminal connected to the cathode layer of the capacitor element are connected such that a part of each terminal is exposed from the exterior resin. A method of manufacturing a chip-type solid electrolytic capacitor formed on a lead frame having a plurality of repeating units having portions serving as the anode terminal and the cathode terminal and capable of mounting a plurality of the capacitor elements. A mounting process for mounting the
An adhering step of adhering an adhesive tape to the non-mounting surface of the capacitor element of the lead frame after the mounting step, and an adjoining capacitor element mounted on the lead frame to which the adhesive tape is adhered is attached to the exterior resin. A method for producing a chip-type solid electrolytic capacitor, comprising: at least a coating step of forming a continuous body of capacitors by forming a coating thereon, and a cutting step of cutting the continuous body of capacitors into a predetermined shape. 2. The method for manufacturing a chip-type solid electrolytic capacitor according to claim 1, wherein the pressure-sensitive adhesive tape has heat resistance that does not cause significant thermal deformation even under heating conditions applied in the coating step. 3. The method according to claim 2, wherein the base film of the pressure-sensitive adhesive tape is a polyimide film having a predetermined thickness. 4. The chip type according to claim 1, wherein the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape has heat resistance that does not cause a significant decrease in adhesive force even under heating conditions applied in the coating step. Manufacturing method of solid electrolytic capacitor. 5. The pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape has an appropriate release property without adhering to the exterior resin.
5. The method for manufacturing a chip-type solid electrolytic capacitor according to any one of claims 1 to 4. 6. The method according to claim 4, wherein the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape is formed of an organic silicon-based polymer pressure-sensitive adhesive. 7. The method according to claim 1, wherein in the covering step, the external atmosphere of the lead frame is set to a predetermined low pressure state.
7. The method for producing a chip-type solid electrolytic capacitor according to any one of 6.