JP3478041B2 - Manufacturing method of chip-shaped solid electrolytic capacitor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a chip solid electrolytic capacitor.

[0002]

2. Description of the Related Art In recent years, the number of chip parts has rapidly increased due to the miniaturization of electronic equipment and the progress of surface mounting technology. In the chip-type solid electrolytic capacitor, further miniaturization and cost reduction of the chip component itself are required as the miniaturization and the increase in capacity progress.

A conventional method for manufacturing a chip-shaped solid electrolytic capacitor will be described below. FIG. 3 is a sectional view of a conventional chip-shaped solid electrolytic capacitor. In FIG. 3, reference numeral 1 denotes a porous anode body formed by molding and sintering tantalum metal powder which is a valve metal, and a part of an anode lead wire 2 composed of a tantalum wire led from the anode body 1 and the anode body 1.
A dielectric oxide film 3 is formed on the entire surface of the substrate by anodic oxidation, and a solid electrolyte layer 4 of manganese dioxide or the like is further formed on the surface of the dielectric oxide film 3.

Reference numeral 5 denotes an insulating plate mounted on the anode lead-out wire 2. The insulating plate 5 prevents manganese nitrate from crawling up and adhering to manganese dioxide on the anode lead-out wire 2 when the solid electrolyte layer 4 is formed. Is. In addition, the solid electrolyte layer 4
A capacitor layer 7 is formed by forming a cathode layer 6 on which a carbon layer and a conductive resin layer containing silver metal are sequentially laminated by an immersion method. Reference numeral 8 denotes a cathode conductor layer, and this cathode conductor layer 8 is a chip-shaped metal 9 made of silver, copper, nickel, or iron metal in a portion of the capacitor element 7 located on the side opposite to the anode lead-out line 2 of the cathode layer 6. Are connected by an epoxy-based conductive resin layer 10 containing silver metal. Thereafter, the capacitor element 7 and the cathode conductor layer 8 are covered with the exterior resin layer 11 so that the anode lead wire 2 is drawn out to one side and a part of the cathode conductor layer 8 is exposed to the outside.
Cover with.

Next, a process of applying a voltage at a high temperature of 150 ° C. or lower is applied to improve the electric characteristics of the capacitor. In some cases, heat treatment is performed in high temperature air. Then, after forming an electroless plating layer on the anode lead-out surface 12 of the anode lead-out wire 2 and the anode lead-out wire 2 and the cathode lead-out surface 13 of the cathode conductor layer 8 on the expose side in the exterior resin layer 11, The conductor layer of electrolytic plating or a conductive resin layer, the anode side external terminal layer 14 including the solder metal layer, and the cathode side external terminal layer 15 are formed.

[0006]

However, in the above-described conventional chip-shaped solid electrolytic capacitor, when the voltage application process at a high temperature is performed with the cathode conductor layer 8 exposed on the cathode lead-out surface 13, Since the exposed surface area of the cathode conductor layer 8 on the side to which the contact pin as a terminal is connected is small, it is difficult to apply a simple and reliable voltage using the contact pin. The high-temperature heat treatment performed in the state where the body layer 8 is exposed oxidizes the surface of the exposed cathode conductor layer 8, or impurities are attached to the surface of the cathode conductor layer 8 to cause an external terminal on the cathode side. There is a problem that the electrical connection between the layer 15 and the cathode conductor layer 8 and the surface shape are deteriorated.

The present invention solves the above-mentioned problems of the prior art, and voltage application processing (aging processing) at high temperature for improving the electrical characteristics of a capacitor can be reliably and easily performed, and An object of the present invention is to provide a method for manufacturing a chip solid electrolytic capacitor, which can easily perform heat treatment in a high-temperature atmosphere to improve the reliability of heat resistance without damaging the electrical connection property and surface shape of the capacitor. To do.

[0008]

In order to achieve the above object, a method for manufacturing a chip solid electrolytic capacitor of the present invention comprises:
A dielectric oxide film, a solid electrolyte layer, and a cathode layer are provided on an anode body made of a valve metal in which the anode lead wire is embedded so that one end of the anode lead wire is exposed to form a capacitor element. Form a cathode conductor layer, and then coat the capacitor element with an exterior resin layer so that a part of the anode lead wire and a part of the cathode conductor layer are exposed to the outside, and then the cathode conductor layer. A surface conductor layer is formed on the cathode lead-out surface of the exterior resin layer in which part of the body layer is exposed to the outside, and in this state, either voltage application treatment (aging treatment) at high temperature or heat treatment in high temperature atmosphere is performed. Give one or both,
Thereafter, the surface conductor layer is removed, and thereafter, the anode side external terminal layer and the cathode side are connected so as to be connected to a part of the anode lead wire exposed from the exterior resin layer and a part of the cathode conductor layer. An external terminal layer is formed. According to this manufacturing method, the voltage application process (aging process) at high temperature for improving the electrical characteristics of the capacitor can be reliably and easily performed, and heat resistance is improved. The heat treatment in a high temperature atmosphere for improving the reliability of can be easily performed without damaging the electrical connection property and surface shape of the capacitor.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The invention according to claim 1 of the present invention is directed to an anode body made of a valve metal in which an anode lead-out wire is embedded so that one end of the anode lead-out wire is exposed. An electrolyte layer and a cathode layer are provided to form a capacitor element,
Further, a cathode conductor layer is formed on the cathode layer, and thereafter,
The capacitor element was covered with an exterior resin layer so that a part of the anode lead wire and a part of the cathode conductor layer were exposed to the outside, and then a part of the cathode conductor layer was exposed to the outside. A surface conductor layer is formed on the cathode lead-out surface of the exterior resin layer, and in this state, one or both of voltage application treatment (aging treatment) in high temperature and heat treatment in high temperature atmosphere is performed, and then the surface The conductor layer is removed, and thereafter, the anode-side external terminal layer and the cathode-side external terminal layer are connected so as to be connected to a part of the anode lead wire exposed from the exterior resin layer and a part of the cathode conductor layer. According to this manufacturing method, since the surface conductor layer is formed on the cathode lead-out surface of the exterior resin layer where a part of the cathode conductor layer is exposed to the outside, the surface conductor layer By its presence, it is electrically conductive with the cathode conductor layer Therefore, the voltage application process (aging process) at high temperature to improve the electrical characteristics of the capacitor can be ensured by using the contact pin as the negative terminal of the voltage application. It can be easily performed, and even when performing heat treatment in a high temperature atmosphere to improve the reliability of heat resistance,
Since the surface conductor layer covers a part of the cathode conductor layer exposed to the outside of the exterior resin layer and functions as a protective film, the surface of the cathode conductor layer is oxidized or the surface of the cathode conductor layer is No more impurities attached to the surface,
This makes it possible to easily perform the heat treatment without deteriorating the electrical connectivity and surface shape of the cathode-side external terminal layer and the cathode conductor layer.

According to the second aspect of the present invention, the surface conductor layer is formed of at least one of carbon paste and conductive paste. According to this structure, the electrical characteristics of the capacitor are improved. Even when the voltage application process (aging process) is performed at a high temperature, the voltage application process (aging process) can be reliably performed because the electrical conduction with the cathode conductor layer is ensured.

According to the third aspect of the invention, the surface conductor layer is removed by sandblasting. According to this structure, the surface conductor layer can be easily removed at low cost. Is something that can be done.

According to a fourth aspect of the present invention, the high temperature atmosphere comprises at least one of a molten metal state, a constant temperature furnace and a high temperature atmosphere of an infrared furnace.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a chip solid electrolytic capacitor according to an embodiment of the present invention,
2 (a), (b), (c), (d), (e),
FIG. 6F is an external perspective view showing the manufacturing process of the chip solid electrolytic capacitor according to the embodiment of the present invention.

In FIG. 1, reference numeral 21 denotes a porous anode body formed by molding and sintering tantalum metal powder which is a valve metal, and the anode lead wire 22 is exposed at one end of the anode body 21. 22 is buried. A water-repellent insulating plate 23 is attached to one end of the exposed anode lead wire 22. A series of processing steps on the surface of the anode body 21 is shown in FIG.
It is performed in a state where the anode lead wire 22 is connected to the metal ribbon 24 shown in (a). First, the entire surface of the anode body 21 and the anode lead wire 22
A dielectric oxide film 25 is formed by anodic oxidation on a part of
Further, the solid electrolyte layer 26 of manganese dioxide is formed on the surface of the dielectric oxide film 25 by thermally decomposing manganese nitrate in a high temperature atmosphere.

A cathode layer 27 in which a carbon layer and a conductive resin layer containing silver are sequentially laminated is formed on the solid electrolyte layer 26 by a dipping method to form a capacitor element 28. Reference numeral 29 denotes a cathode conductor layer, and this cathode conductor layer 29 is provided on a portion of the capacitor element 28 on the side opposite to the anode lead wire 22 of the cathode layer 27 with silver, copper, nickel,
A chip-shaped metal 30 made of iron metal is connected by an epoxy-based conductive resin layer 31 containing silver metal. 32 is an exterior resin layer, and this exterior resin layer 32 is
The capacitor element 28 is set in a molding die so that the anode lead wire 22 is drawn out to one side, and the cathode conductor layer 2
It is formed by transfer molding or injection molding using epoxy resin so that 9 and the capacitor element 28 are entirely covered with resin.

Then, by cutting or grinding the portion of the molded body 33 of the exterior resin layer 32 after the resin exterior, which is opposite to the anode lead wire 22, a cathode lead-out surface 34 is formed as shown in FIG. 2 (a). In addition, a part of the cathode conductor layer 29 is exposed.

Reference numeral 35 denotes a surface conductor layer formed on the cathode lead-out surface 34 of the exterior resin layer 32 as shown in FIG. 2B. The surface conductor layer 35 is an aqueous carbon solution or a carbon paste of acrylic resin. It is formed by applying it to the cathode lead-out surface 34 by a dipping method or a dispenser method and drying it. The surface conductor layer 35 is not limited to the carbon paste, and the surface conductive layer 35 is made of a conductive paste made of a metal such as silver, copper, or nickel and any of acrylic resin, polyester resin, and epoxy resin. The body layer 35 may be formed.

FIG. 2C shows the state of the voltage application process (aging process) at a high temperature.
The contact pin 36a as a positive terminal is contacted with the contact pin 36b, while the contact pin 36b as a negative terminal is contacted with the surface conductor layer 35, and a voltage is applied at a high temperature of 150 ° C. or less The application process (aging process) is performed.

FIG. 2 (d) shows the state of heat treatment in a high temperature atmosphere, 37 is a high temperature atmosphere, and this high temperature atmosphere 37 is a state in which a metal composed of solder and tin is melted at a temperature of 300 ° C. or less. In the molten state of this metal, the exterior resin layer 32 in which the surface conductor layer 35 is formed in this molten metal is shown.
By immersing the molded body 33 in No. 3, heat treatment is performed in the high temperature atmosphere 37. In addition, this high temperature atmosphere 37
Is not limited to the molten state of the metal, and may be a high temperature atmosphere of a constant temperature furnace or an infrared furnace.

FIG. 2 (e) shows a voltage application process (aging process) at a high temperature shown in FIG. 2 (c) and FIG. 2 (d).
After finishing the heat treatment in the high temperature atmosphere 37 shown in (4), the surface conductor layer 35 is removed by sandblasting,
The exterior resin layer 32, a part of the anode lead wire 22 exposed from the exterior resin layer 32, and the cathode lead-out surface 34 are roughened by sandblasting, and then the metal ribbon 2
The anode lead-out wire 22 is separated from No. 4 to make the outside dimension length of the product almost.

FIG. 2 (f) shows an anode side external terminal layer 38 and a cathode side external terminal so as to be connected to a part of the anode lead wire 22 exposed from the exterior resin layer 32 and a part of the cathode conductor layer 29. The state in which the layer 39 is formed is shown. The anode-side external terminal layer 38 includes a part of the anode lead wire 22 and the exterior resin layer 3
2 is formed on the surface of the anode lead-out surface 40 and the exterior resin layer 32 located around it, while the cathode side external terminal layer 39 is the cathode lead-out surface 34 of the exterior resin layer 32 and the exterior resin layer 32 located around it. Is formed on the surface of.

The anode-side external terminal layer 38 and the cathode-side external terminal layer 39 are covered with an anode-side solder metal layer 41 and a cathode-side solder metal layer 42 as shown in FIG. The anode-side external terminal layer 38 and the cathode-side external terminal layer 39 are formed by an electroless plating layer obtained by electroless plating of nickel or copper, a wet method of electrolytic plating, a dry method of vapor deposition, or ion sputtering. The anode side solder metal layer 41 and the cathode side solder metal layer 42 are formed by solder coating with molten solder or electrolytic solder plating.

In the above-described embodiment of the present invention, the surface conductor layer 35 is formed on the cathode lead-out surface 34 of the exterior resin layer 32 in which a part of the cathode conductor layer 29 is exposed to the outside. Due to the presence of the surface conductor layer 35,
The area electrically connected to the cathode conductor layer 29 is increased, and as a result, in order to improve the electrical characteristics of the capacitor, a voltage application process at a high temperature as shown in FIG. 2C is performed. Even when the (aging treatment) is performed, it can be surely and easily performed by using the contact pin 36b as a negative terminal for voltage application, and in order to improve the reliability of heat resistance, it is shown in FIG. 2 (d). Even when the heat treatment is performed in the high temperature atmosphere 37 as described above, the cathode conductor layer 2 in which the surface conductor layer 35 is exposed to the outside of the exterior resin layer 32.
Since it covers a part of 9 and functions as a protective film, the surface of the cathode conductor layer 29 is not oxidized and impurities are not attached to the surface of the cathode conductor layer 29. The heat treatment can be easily carried out without deterioration in the electrical connectivity and surface shape between the cathode side external terminal layer 39 and the cathode conductor layer 29.

In the above-described embodiment of the present invention, the case where both the voltage application process (aging process) at a high temperature and the heat treatment in the high temperature atmosphere 37 are performed has been described. Only one of them may be performed.

[0025]

As described above, according to the method for manufacturing the chip solid electrolytic capacitor of the present invention, the anode body made of the valve action metal in which the anode lead wire is embedded so that one end of the anode lead wire is exposed is dielectrically oxidized. A capacitor, a solid electrolyte layer, and a cathode layer are provided to form a capacitor element, and a cathode conductor layer is formed on the cathode layer. Thereafter, a part of the anode lead wire and a part of the cathode conductor layer are externally formed. To cover the capacitor element with an exterior resin layer, and then a surface conductor layer is formed on the cathode lead-out surface of the exterior resin layer in which a part of the cathode conductor layer is exposed to the outside. In this state, one or both of a voltage application treatment (aging treatment) in a high temperature and a heat treatment in a high temperature atmosphere is performed, and then the surface conductor layer is removed, and then exposed from the exterior resin layer. Part of the anode lead wire The anode-side external terminal layer and the cathode-side external terminal layer are formed so as to be connected to a part of the cathode conductor layer, and according to this manufacturing method, a part of the cathode conductor layer is exposed to the outside. Since the surface conductor layer is formed on the cathode lead-out surface of the exterior resin layer, the presence of this surface conductor layer expands the area electrically connected to the cathode conductor layer, thereby increasing the capacitor. The voltage application process (aging process) at a high temperature to improve the electrical characteristics of the can be reliably and easily performed by using the contact pin as the negative terminal of the voltage application, and the reliability of heat resistance can be improved. Even when performing heat treatment in a high-temperature atmosphere to improve, because the surface conductor layer covers a part of the cathode conductor layer exposed to the outside of the exterior resin layer and functions as a protective film, Conductor layer The surface does not oxidize and impurities do not adhere to the surface of the cathode conductor layer, which deteriorates the electrical connectivity and surface shape between the cathode side external terminal layer and the cathode conductor layer. Without that, the heat treatment can be easily performed.

[Brief description of drawings]

FIG. 1 is a sectional view showing a chip solid electrolytic capacitor according to an embodiment of the present invention.

2A to 2F are perspective views showing the appearance of the same chip solid electrolytic capacitor manufacturing process.

FIG. 3 is a sectional view showing a conventional chip solid electrolytic capacitor.

[Explanation of symbols]

21 Anode body 22 Anode lead wire 25 Dielectric oxide film 26 Solid electrolyte layer 27 cathode layer 28 Capacitor element 29 Cathode conductor layer 32 Exterior resin layer 34 Cathode derivation surface 35 Surface Conductor Layer 37 High temperature atmosphere 38 Anode side external terminal layer 39 Cathode side external terminal layer

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sumio Nishiyama 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) Reference JP-A-7-240346 (JP, A) JP-A-5- 226192 (JP, A) JP-A-54-127564 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01G 9/04 307 H01G 9/00 H01G 9/012

Claims (4)

(57) [Claims] 1. A capacitor element is constructed by providing a dielectric oxide film, a solid electrolyte layer, and a cathode layer on an anode body made of a valve metal in which the anode lead wire is embedded so that one end of the anode lead wire is exposed. Further, a cathode conductor layer is formed on the cathode layer, and then the capacitor element is covered with an exterior resin layer so that a part of the anode lead wire and a part of the cathode conductor layer are exposed to the outside, Next, a surface conductor layer is formed on the cathode lead-out surface of the exterior resin layer in which a part of the cathode conductor layer is exposed to the outside, and in this state, a voltage application process (aging process) at high temperature and a high temperature atmosphere are performed. Either one or both of the heat treatments in the above step, and then removing the surface conductor layer,
After that, a chip-shaped solid electrolytic capacitor in which an anode-side external terminal layer and a cathode-side external terminal layer are formed so as to be connected to a part of the anode lead wire and a part of the cathode conductor layer exposed from the exterior resin layer. Manufacturing method. 2. The surface conductor layer is composed of at least one of carbon paste and conductive paste.
A method for manufacturing the chip-shaped solid electrolytic capacitor described in. 3. The method for manufacturing a chip solid electrolytic capacitor according to claim 1, wherein the removal of the surface conductor layer is performed by sandblasting. 4. The high temperature atmosphere is a molten state of metal, a constant temperature furnace,
The method for manufacturing a chip solid electrolytic capacitor according to claim 1, wherein the solid electrolyte capacitor has at least one type of high temperature atmosphere in an infrared furnace.