JP2002260967A - Solid electrolytic capacitor in contact with substrate, solid electrolytic capacitor incorporating wiring board, and electronic equipment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor in contact with a thin substrate, which can be incorporated on a substrate, the electrolytic capacitor incorporating wiring board which has a solid electrolytic capacitor inside, and electronic equipment using them. SOLUTION: The solid electrolytic capacitor 1 has a solid electrolytic layer 4 of polypyrol formed in an area except one end 6 of valve metal foil 2 on an anodized film 3 formed on the valve metal foil 2, and a conductive layer 5 of silver paste formed on the solid electrolytic layer 4. A thin cathode 7 is connected to the reverse surface 51 of the part where the conductive layer 5 is formed, and the flank and top surface except the connection area of the cathode 7 are coated with insulating resin 8. At one end 6 of the valve metal foil 2, a thin anode 9 is connected to the top surface 61 and coated with insulating resin 10 except the connection area of the anode 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate-contact solid electrolytic capacitor, a wiring board with a built-in solid electrolytic capacitor, and an electronic apparatus using the wiring board. More specifically, the present invention relates to a thinned structure of a solid electrolytic capacitor.

[0002]

2. Description of the Related Art In recent years, in small electronic devices such as mobile phones and mobile computers, it has been studied to reduce the size and weight of electronic devices by increasing the integration of various electronic components. A typical example of this approach is to build a passive component such as a ceramic capacitor on the same wiring board as the active equipment, and then mount an aluminum electrolytic capacitor that cannot be mounted on the board later. is there.

[0003]

With the development of solid electrolytes for aluminum electrolytic capacitors and the like, the possibility has emerged that the solid electrolytic capacitors can be built into the substrate. It must be thin, but such a thin solid electrolytic capacitor has not been devised yet.

Accordingly, an object of the present invention is to provide a thin substrate-contact solid electrolytic capacitor which can be built in a substrate,
An object of the present invention is to provide a wiring board with a built-in electrolytic capacitor incorporating the solid electrolytic capacitor and an electronic device using the same.

[0005]

Means for Solving the Problems To solve the above problems, a substrate contact type solid electrolytic capacitor according to the present invention comprises
Anodized valve metal foil, a solid electrolyte layer formed on a region of the anodic oxide film formed on the valve metal foil excluding one end of the valve metal foil, and the solid electrolyte layer A conductive layer formed thereon, and at one end of the valve metal foil, a thin anode is connected to one of the two surfaces, and a connection region of the anode is formed. In the portion where the insulating resin is coated and the conductive layer is formed, a thin cathode is connected to one of the two surfaces, and the insulating resin is removed except for the connection region of the cathode. Is characterized by being coated.

[0006] In the solid electrolytic capacitor constructed as described above, since a foil is used for the element, it can be manufactured to be thin. Further, since the anode and the cathode are thin and are connected not to both sides of the valve metal foil but only to one side, a thin solid electrolytic capacitor can be manufactured. Moreover,
Since the resin coating is applied except for the connection region between the anode and the cathode, it has sufficient strength even when a thin foil is used. Furthermore, the solid electrolytic capacitor according to the present invention can be mounted in a state in which it is in close contact with the substrate. For this reason, it can be built in a multilayer substrate or the like, so that the integration of electronic components can be increased. Furthermore, since the anode and the cathode can be connected to any of the two surfaces of the valve metal foil, when the anode and the cathode are incorporated in a multilayer substrate or the like, they can be placed at arbitrary positions according to the position of the wiring pattern of the multilayer substrate. An anode and a cathode can be arranged.

In the present invention, the valve metal foil is a foil made of aluminum, tantalum, niobium, zirconium, titanium or an alloy thereof.

In the present invention, at least one of the anode and the cathode is formed of a thin metal plate or a metal film formed by a sputtering method or the like.

In the present invention, the anode and the cathode may be connected to the valve metal foil on opposite sides of the valve metal foil, or may be positioned in the same direction as the valve metal foil. Any configuration may be used that is connected to the valve metal foil on the surface to be formed.

In a wiring board with a built-in solid electrolytic capacitor incorporating a solid electrolytic capacitor in close contact with a substrate to which the present invention is applied, a wiring pattern formed on the substrate is electrically connected to the anode and the cathode of the solid electrolytic capacitor in close contact with the substrate. Connection.

[0011] The solid electrolytic capacitor according to the present invention may be incorporated in a multilayer substrate in which the wiring pattern is formed in multiple layers.

The wiring board with a built-in solid electrolytic capacitor to which the present invention is applied can increase the integration of various electronic components. If it is used for small electronic devices such as mobile phones and mobile computers, the size of the electronic devices can be reduced. Weight and weight can be reduced.

[0013]

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

[Basic Structure of Capacitor Element] FIG.
(A) and (B) are an explanatory view showing a basic structure of an element of a solid electrolytic capacitor to which the present invention is applied, and a cross-sectional view showing an enlarged part (a part surrounded by a dotted line A) of the element. FIG.

1 (A) and 1 (B), a solid electrolytic capacitor 1 of the present embodiment comprises an anodized valve metal foil 2;
Among the anodic oxide film 3 formed on the valve metal foil 2, a solid electrolyte layer 4 such as polypyrrole, ponyaniline, or polythiophene formed on a region excluding one end 6 of the valve metal foil 2, And a conductive layer 5 such as a silver paste formed on the electrolyte layer 4. In addition, valve metal foil 2
Is insulated and separated by an insulating resin 11 from the end on which the solid electrolyte layer 4 and the conductive layer 5 are formed.

The valve metal foil 2 used here is approximately 80 μm to 2 μm anodized after etching (roughening).
This aluminum foil is cut into predetermined dimensions after performing etching (roughening treatment) and anodic oxidation continuously in a strip-like state, and then cutting out the cut to a predetermined size. Oxidized. It is preferable that anodic oxidation is performed on this cut except for the cut at one end 6.

As the valve metal foil 2, tantalum, niobium,
A foil made of zirconium, titanium or an alloy thereof may be used. When a tantalum foil or a niobium foil is used, the solid electrolyte layer 4 is not limited to a conductive polymer,
A solid electrolyte made of a metal oxide such as manganese dioxide or lead dioxide can also be used.

For the capacitor element 1 'thus constructed, as will be described later in each embodiment, a thin cathode is provided on one of the two surfaces of the portion where the conductive layer 5 is formed. It is connected, and the insulating resin is coated except for the connection region of the cathode. The selective coating of such an insulating resin is performed by a method of selectively applying the resin, and after the resin is applied to the entire surface of the target area, the resin is partially removed by machining such as polishing to form the cathode. Can be realized by a method for securing the connection area of As the cathode, a thin metal plate such as a copper-nickel alloy may be connected to the conductive layer with a silver paste or the like, but a metal film such as a copper-nickel alloy is formed in a predetermined region on the conductive layer via a metal mask or the like. It may be formed by sputtering.

On the other hand, one end 6 of the valve metal foil 2
Then, a thin anode is connected to one of the two surfaces, and an insulating resin is coated except for a connection region of the anode. The selective coating of such an insulating resin is also performed by a method of selectively applying the resin, and after the resin is applied to the entire surface of the target region, the resin is partially removed by machining such as polishing to form the cathode. Can be realized by a method for securing the connection area of As the anode, similarly to the cathode, a thin metal plate such as a copper-nickel alloy may be connected to the conductive layer with a silver paste or the like. May be formed by sputtering. Further, since the anodic oxide film 3 is also formed in the region where the anode is to be connected, this portion is immersed in an electroless copper plating bath to form an extremely thin underlayer on the surface of the anodic oxide film 3, and thereafter Alternatively, a thin solder layer may be formed on the surface.

[Embodiment 1] FIGS. 2A and 2B are explanatory views showing the structure of a solid electrolytic capacitor according to Embodiment 1 of the present invention, and a part of the capacitor (indicated by a dotted line B) It is a sectional view which expands and shows (enclosed part).

2 (A) and 2 (B), a solid electrolytic capacitor 1 of the present embodiment comprises an anodized valve metal foil 2;
Among the anodic oxide film 3 formed on the valve metal foil 2, a solid electrolyte layer 4 such as polypyrrole, ponyaniline, or polythiophene formed on a region excluding one end 6 of the valve metal foil 2, And a conductive layer 5 such as a silver paste formed on the electrolyte layer 4. The valve metal foil 2 used here is an aluminum foil of about 80 μm to 200 μm that has been anodized after etching (roughening). Note that one end 6 of the valve metal foil 2 is insulated and separated from the side on which the solid electrolyte layer 4 and the conductive layer 5 are formed by an insulating resin 11.

In the present embodiment, a thin cathode 7 is connected to the lower surface 51 of the capacitor element 1 ′ having the above-described structure, on both surfaces of the portion where the conductive layer 5 is formed. The insulating resin 8 is coated on the side surface and the upper surface except for the connection region of FIG. The insulating resin 8 runs over the insulating resin 11 on the upper surface and protrudes to one end 6. On the other hand, at one end 6 of the valve metal foil 2, the thin anode 9 is connected to the upper surface 61 of both surfaces thereof, and the insulating resin 10 is coated except for the connection region of the anode 9. ing. The insulating resin 10 runs over the insulating resin 11 on the lower surface and protrudes near the end of the cathode 7.

Here, the anode 9 is connected to the other end 12 along the upper surface of the insulating resin 8 on the cathode side on the upper surface of the valve metal foil 2.
It extends to near.

The solid electrolytic capacitor 1 constructed as described above
Since a foil is used for the capacitor element 1 ′, it can be manufactured thin. Further, since the anode 9 and the cathode 7 are thin and are connected not to both sides of the valve metal foil 2 but to only one side, the solid electrolytic capacitor 1 can be manufactured thin. In addition, since the insulating resins 8 and 10 are coated except for the connection region between the anode 9 and the cathode 7, sufficient strength is obtained even when a thin foil is used.

Here, regarding the anode 9 and the cathode 7,
Since it is possible to connect to either of the two surfaces of the valve metal foil 2, in the present embodiment, the wiring pattern 22 of the lower substrate 21 constituting the multilayer substrate 20 is formed on the upper substrate constituting the multilayer substrate. The cathode 7 is arranged on the lower surface side in correspondence with the wiring pattern 23 being positive,
The anode 9 is arranged on the upper surface side.

As described above, the solid electrolytic capacitor 1 of the present embodiment is quite thin and can be mounted in close contact with the substrate. For this reason, since it can be built in the multilayer substrate 20, the integration of electronic components can be enhanced. Therefore, if the multilayer substrate 20 with a built-in capacitor is used for a small electronic device such as a mobile phone and a mobile computer, the size and weight of the electronic device can be reduced.

[Embodiment 2] FIGS. 3A and 3B are explanatory views showing the structure of a solid electrolytic capacitor according to Embodiment 2 of the present invention, and a part of this capacitor (in a dotted line C, respectively). (Enclosed portion) is an enlarged sectional view.

3 (A) and 3 (B), a solid electrolytic capacitor 1 according to the present embodiment has an anodized valve metal foil 2 and an anode formed on the valve metal foil 2 as in the first embodiment. A solid electrolyte layer 4 formed on a region of the oxide film 3 excluding one end 6 of the valve metal foil 2 and a conductive layer 5 such as a silver paste formed on the solid electrolyte layer 4 Have. The valve metal foil 2 used here is anodized about 80 μm to 200 μm after the etching treatment (roughening treatment).
m of aluminum foil. Note that one end 6 of the valve metal foil 2 is insulated and separated from the side on which the solid electrolyte layer 4 and the conductive layer 5 are formed by an insulating resin 11.

In the capacitor element 1 'thus configured, in the present embodiment, as in the first embodiment, the thin cathode 7 is formed on the lower surface 51 of both surfaces of the portion where the conductive layer 5 is formed. Are connected, and an insulating resin 8 is coated on the side surface and the upper surface except for the connection region of the cathode 7. On the other hand, at one end 6 of the valve metal foil 2, the thin anode 9 is connected to the upper surface 61 of both surfaces thereof, and the insulating resin 10 is removed except for the connection region of the anode 9.
Is coated.

Here, the anode 9 is formed only at one end 6 on the upper surface of the valve metal foil 2, and does not extend to the cathode side.

The solid electrolytic capacitor 1 constructed as described above
However, since a foil is used for the capacitor element 1 ', it can be manufactured thin. Further, since the anode 9 and the cathode 7 are thin and are connected not to both sides of the valve metal foil 2 but to only one side, the solid electrolytic capacitor 1 can be manufactured thin. In addition, since the insulating resins 8 and 10 are coated except for the connection region between the anode 9 and the cathode 7, sufficient strength is obtained even when a thin foil is used. Furthermore, in the present embodiment, since the anode 9 is set to the minimum necessary size, there is almost no inductance due to the anode 9 and the impedance characteristic is excellent.

Also in this embodiment, the solid electrolytic capacitor 1
In order to incorporate the cathode 7 into the lower surface of the lower substrate 21 and to increase the wiring pattern 23 formed on the upper substrate constituting the multilayer substrate, Placed on the side and the anode 9
Is arranged on the upper surface side.

As described above, the solid electrolytic capacitor 1 of the present embodiment is also quite thin and can be mounted in close contact with the substrate. For this reason, since it can be built in the multilayer substrate 20, the integration of electronic components can be enhanced. Therefore, if the multilayer substrate 20 with a built-in capacitor is used for small electronic devices such as mobile phones and mobile computers, the size and weight of the electronic devices can be reduced.

[Other Embodiments] In the solid electrolytic capacitor 1 to which the present invention is applied, since the anode 9 and the cathode 7 can be connected to either of the two surfaces of the valve metal foil 2, the multilayer substrate 20 4A, for example, as shown in FIG. 4A, the capacitor element 1 'is thinner on the lower surface 51 of both surfaces of the portion where the conductive layer 5 is formed. Aside from the connection area of the cathode 7, the side and the top are coated with the insulating resin 8, while the one end 6 of the valve metal foil 2 is connected.
Then, among the two surfaces, the thin anode 9
And the insulating resin 10 except for the connection region of the anode 9
May be coated.

As shown in FIG. 4B, a thin cathode 7 is connected to the lower surface 51 of the capacitor element 1 'on both surfaces of the portion where the conductive layer 5 is formed.
Except for the connection region of the cathode 7, the side and top surfaces are coated with an insulating resin 8, while at one end 6 of the valve metal foil 2, a thin anode 9 is formed on the top surface 61 of the two surfaces. The connection may be made, and the insulating resin 10 may be coated except for the connection region of the anode 9, and the anode 9 may be drawn downward along the side end surface of the valve metal foil 2 and bent outward.

Further, as shown in FIG. 4C, a thin cathode 7 is connected to the upper surface 52 of the capacitor element 1 'on both surfaces of the portion where the conductive layer 5 is formed. Except for the connection region of the cathode 7, the side and the lower surface are coated with an insulating resin 8, and at one end 6 of the valve metal foil 2, a thin anode 9 is formed on the upper surface 61 of both surfaces. The connection may be made, and the insulating resin 10 may be coated except for the connection region of the anode 9.

[0037]

As described above, according to the present invention, a thin solid electrolytic capacitor can be manufactured because a foil is used for the element of the solid electrolytic capacitor. Further, since the anode and the cathode are thin and are connected not to both sides of the valve metal foil but only to one side, a thin solid electrolytic capacitor can be manufactured. Moreover, since the resin coating is applied except for the anode and cathode connection areas,
It has sufficient strength even when a thin foil is used. Furthermore, since the anode and the cathode can be connected to any of the two surfaces of the valve metal foil, when embedded in a multilayer substrate or the like, they can be connected to any positions according to the position of the wiring pattern of the multilayer substrate. An anode and a cathode can be arranged.

[Brief description of the drawings]

FIGS. 1A and 1B are an explanatory view showing a basic structure of an element of a solid electrolytic capacitor to which the present invention is applied, and a sectional view showing a part of the element in an enlarged manner.

FIGS. 2A and 2B are an explanatory view showing a structure of a solid electrolytic capacitor according to Embodiment 1 of the present invention, and a cross-sectional view showing an enlarged part of the capacitor.

FIGS. 3A and 3B are an explanatory view showing a structure of a solid electrolytic capacitor according to a second embodiment of the present invention, and a cross-sectional view showing a part of the capacitor in an enlarged manner.

FIGS. 4A, 4B, and 4C are explanatory diagrams each showing a modified example of the solid electrolytic capacitor of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 solid electrolytic capacitor 1 ′ capacitor element 2 valve metal foil 3 anodized film 4 solid electrolyte layer 5 conductive layer 6 one end of valve metal foil 7 cathode 8, 10, 11 insulating resin 9 anode 20 multilayer with built-in electrolytic capacitor Substrate (wiring board) 22, 23 Wiring pattern

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Koji Omori, 13-5 Daimon Izumicho, Shiojiri, Nagano Prefecture, Japan (72) Inventor Takashi Mochizuki 13-5, Omon Izumicho, Shiojiri, Nagano Prefecture, Sanshin F Terms (reference) 5E346 BB01 BB20 HH24

Claims (9)

[Claims] 1. An anodized valve metal foil, and a solid electrolyte layer formed on a region of the anodized film formed on the valve metal foil except for one end of the valve metal foil. A conductive layer formed on the solid electrolyte layer, and at one end of the valve metal foil, a thin anode is connected to one of the two surfaces, In a portion where the insulating resin is coated except for a connection region of the anode, and a portion where the conductive layer is formed, a thin cathode is connected to one of the two surfaces, and a connection region of the cathode is formed. A substrate contact type solid electrolytic capacitor characterized by being coated with an insulating resin except for (1). 2. The solid electrolytic capacitor according to claim 1, wherein the valve metal foil is a foil made of aluminum, tantalum, niobium, zirconium, titanium, or an alloy thereof. 3. The solid electrolytic capacitor according to claim 1, wherein at least one of the anode and the cathode is formed of a thin metal plate. 4. The solid electrolytic capacitor according to claim 1, wherein at least one of the anode and the cathode is made of a metal film. 5. The method according to claim 1, wherein
The substrate-contact solid electrolytic capacitor, wherein the anode and the cathode are connected to the valve metal foil on opposite sides of the valve metal foil. 6. The method according to claim 1, wherein
The solid electrolytic capacitor in contact with a substrate, wherein the anode and the cathode are connected to the valve metal foil on surfaces of the valve metal foil which are located in the same direction as each other. 7. A wiring board with a built-in solid electrolytic capacitor incorporating the solid electrolytic capacitor in close contact with a substrate as defined in any one of claims 1 to 6, wherein a plurality of wiring patterns formed on the board are provided on the substrate. A wiring board with a built-in solid electrolytic capacitor, which is electrically connected to the anode and the cathode of a contact type solid electrolytic capacitor. 8. The wiring board with a built-in solid electrolytic capacitor according to claim 7, wherein said wiring pattern is formed in multiple layers. 9. An electronic apparatus using the wiring board with a built-in solid electrolytic capacitor as defined in claim 7 or 8.