JPH04101406A - Chip type solid tantalum electrolytic capacitor - Google Patents

Abstract

PURPOSE:To achieve a relatively large surface area, thin tantalum sintered layer that is difficult to break or chip by compression molding a tantalum powder on one side of a tantalum sheet, sintering this, and then forming an oxide film, semiconductor layer, and conduction layer to create a tantalum capacitor element. CONSTITUTION:The embossed sections 4a are formed on the tantalum sheet 3a and a tantalum powder is compression molded on the protruding side of the embossed sections 4a. Next, vacuum sintering is performed and a tantalum sintered body 5a is obtained. After this, the recessed side of the embossed sections 4a on the tantalum sheet 3a is made the anode. In a hydrogen phosphate solution, the surfaces of the tantalum sintered body 5a and the protruding side of the embossed sections 4a of the tantalum sheet 3a are anodized and a cathode layer consisting of manganese dioxide, graphite, and silver paste is formed. Then the silver paste layer 7a is used to connect the cathode layer 6a and the cathode terminal 1a thereby obtaining a tantalum capacitor. Finally, two tantalum capacitor element are stacked and connected by a conductive resin layer 7b.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a chip type solid electrolytic tantalum capacitor,
In particular, it relates to chip-type solid electrolytic tantalum capacitors that are suitable for thinning.

[Conventional technology]

Conventionally, for this type of chip-type solid electrolytic tantalum capacitor, as shown in FIG. forming the cathode layer 15 using manganese;
The tantalum wire 13 is connected to the cathode terminal plate 11 by a conductive resin layer 16, and the tantalum wire 13 is connected to the anode terminal plate 2 by welding, and is covered with an exterior resin 7, and the anode terminal plate 2 and the cathode terminal protrude from the exterior resin. It had a structure in which the plate 11 was bent along the exterior resin 17.

[Problem to be solved by the invention]

The conventional chip-type solid electrolytic tantalum capacitor described above has a single tantalum wire planted in the center that holds the tantalum sintered body, so it is very difficult to make a thin and flat tantalum sintered body. It is easy to chip and break, and since the purpose of tantalum wire is to hold the tantalum sintered body during the manufacturing process, there are restrictions such as not being able to make it too thin compared to the size of the tantalum sintered body, making it difficult to make it thinner. There was a problem.

In addition, conventional chip-type solid electrolytic tantalum capacitors are
Normally, the rated voltage is 50V or less, so when using it at a voltage higher than 50V, two or more chip-type solid electrolytic tantalum capacitors must be connected in series, and one chip-type solid electrolytic tantalum capacitor must be connected in series. When a series structure is used in a capacitor, the structure is complicated and production is difficult.

A first object of the present invention is to provide a chip-type solid electrolytic tantalum capacitor that is difficult to chip or crack and can be made thin even when a thin tantalum sintered body having a relatively large area is used.

A second object of the present invention is to provide a chip-type solid electrolytic capacitor that can be formed thinly and easily and with high productivity by connecting two or more capacitors in series with a high withstand voltage.

[Means for Solving the Problems] The chip-type solid electrolytic tantalum capacitor of the first aspect of the present invention is produced by press-molding tantalum powder on one side of tantalum foil and sintering it to form an oxide film, a semiconductor layer, and a conductor. The structure is characterized in that its constituent element is a tantalum capacitor element formed by sequentially forming layers.

In addition, the chip type solid electrolytic tantalum capacitor according to the second aspect of the present invention is obtained by press-molding tantalum powder on one side of a tantalum foil and sintering it to form an oxide film.

The device is characterized by having a structure in which two or more tantalum capacitor elements each formed by successively forming a semiconductor layer and a conductor layer are connected in series.

As described above, according to the present invention, a thin chip-type solid electrolytic tantalum capacitor can be easily obtained, and also has a simple structure.
A series connection structure can be created within two chip-type solid electrolytic tantalum capacitors.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a sectional view of a deep type solid electrolytic tantalum capacitor according to an embodiment of the first aspect of the present invention.

First, an embossed portion 4a with a height of 50 μm is provided on a tantalum foil 3a with a thickness of 50 μm.
Tantalum powder was press-molded and vacuum sintered at 1740°C for 60 minutes to form a product with a thickness of 0.2 mm, a width of 1 mm, and a length of 1 m.
A tantalum sintered body 5a was obtained.

Next, using the concave side of the embossed part 4a of the tantalum foil 3a as an anode, the tantalum sintered body 5a and the surface of the convex part of the embossed part 4a of the tantalum foil 3a are heated to 100 V in a 0.1% phosphoric acid aqueous solution at 90°C. 0.1m by anodizing and sequentially applying mancan dioxide, graphite, and silver paste.
A cathode layer with a thickness of m was formed. Thereafter, the cathode layer 6a was connected to the cathode terminal plate 1a having a thickness of 0.1 mm using the silver paste layer 7a.

In addition, the right end of the tantalum foil 3a is connected to the anode terminal plate 2a having a thickness of 0.1 mm, and the exterior resin 8a is used to package the tantalum foil 3a.
The anode terminal plate 2a and the cathode terminal plate of the part protruding from a]
A was bent downward to produce a chip-type solid electrolytic tantalum capacitor with a rated voltage of 35 V, 0.11 μF, and a thickness of 0.8 mm.

FIG. 2 is a longitudinal sectional view of a second embodiment of the first invention of the present invention. In this embodiment, the anode terminal plate 2al and the cathode terminal plate 1
A1 is bent outward, which makes mounting difficult, but it is also characterized by being able to be made thinner by the thickness of the terminal board.

FIG. 3 is a longitudinal sectional view of an embodiment of the second aspect of the present invention, and FIG. 4 is an enlarged view of the tantalum element portion of FIG. 3.

First, as shown in Fig. 4, an embossed part 4b is provided on a 50μ thick tantalum foil 3b, and a 1mm x 2mm, 1m
Form a tantalum powder compact with m thickness and heat at 1800°C17
Sintering was performed for 5 minutes. Next, the sintered tantalum foil 3b and the tantalum sintered body 5b are placed in a 90'C phosphoric acid aqueous solution.
The surfaces of the tantalum sintered body 5b and the tantalum foil 3b that are connected to the tantalum sintered body 5b are soaked, and the tantalum foil 3
The anode was taken out from the side not connected to the tantalum sintered body 5b of b, and a stainless steel plate for the cathode was placed in an aqueous phosphoric acid solution to perform anodic oxidation. Thereafter, the tantalum sintered body 5b is immersed in manganese nitrate, thermally decomposed at 300°C to form a manganese dioxide layer, and graphite and silver paste are applied thereon to form a cathode layer 6b.
A tantalum capacitor element with a rating of 35V was obtained.

Next, two tantalum capacitor elements with a 2 μF rating of 35 V were stacked and connected by a conductive resin layer 7b as shown in FIG. At this time, the tantalum foil 3b of the lower tantalum capacitor element was extended by 1 mm.

Next, the tin foil 10 is connected to the upper tantalum capacitor element through the conductive resin layer 7b, and the left side of the tin foil 10 and the right side of the tantalum foil 3b of the lower tantalum capacitor element are connected to the cathode terminal plate 1b and the anode terminal plate, respectively. 2b was connected to a conductive resin layer 7b and covered with an insulating resin 8b to produce a chip type solid electrolytic capacitor with a 1 μF rating of 70V.

FIG. 5 is a longitudinal sectional view of a second embodiment of the second invention of the present invention. This embodiment is characterized in that the tantalum capacitor elements are arranged in the horizontal direction, allowing a large connection surface with the cathode terminal plate 1b and the anode terminal plate 2b.

〔Effect of the invention〕

As explained above, in the present invention, tantalum powder is pressure-molded on one side of a tantalum foil, and sintered to sequentially form an oxide film, a semiconductor film, and a conductor layer. By using a tantalum capacitor element, the tantalum sintered body is held flat by the tantalum foil, making it difficult to chip or crack even when the tantalum sintered body is relatively large and thin. Since it is possible to hold the capacitor with tantalum foil of the same thickness regardless of its size, it is possible to create a chip-type solid electrolytic tantalum capacitor that is thinner than conventional capacitors.

Furthermore, by connecting two or more tantalum capacitor elements in series that have a thinner structure than the conventional one, it is possible to create a capacitor with a higher withstand voltage than the conventional one.

17...Exterior resin.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of the first invention of the present invention, FIG. 2 is a vertical cross-sectional view of a second embodiment of the first invention of the present invention, and FIG.
The figure is a vertical cross-sectional view of an embodiment of the second invention of the present invention, FIG. 4 is an enlarged view of the tantalum element portion of FIG. 3, and FIG. The top view and FIG. 6 are longitudinal cross-sectional views of an example of a conventional chip-type solid electrolytic tantalum capacitor. la, lal, lb... - cathode terminal plate, 2a, 2a+,
2b...Anode terminal plate, 3a, 3b...Tantalum foil,
4a, 4b... Embossed part, 5a, 5b... Tantalum sintered body, 6a, 6b... Cathode layer, 7a, 7b... Conductive resin layer (silver paste layer), 8a, 8b... Exterior resin, 10... Tin foil, 11... Cathode terminal plate, 12.
... Anode terminal plate, 13... Tantalum wire, 14... Tantalum sintered body, 15... Cathode layer, 16... Conductive resin layer,
] 0 Figure 3 Figure 4 Figure 5 Figure 6 Figure 6 Tantals are almost all conductive in the 11th layer and the 11th layer is thinner.

Claims (2)

[Claims] 1. A chip-type solid electrolytic tantalum whose constituent element is a tantalum capacitor element formed by press-molding tantalum powder on one side of tantalum foil, sintering it, and sequentially forming an oxide film, a semiconductor layer, and a conductor layer. capacitor. 2. It is characterized by having a structure in which two or more tantalum capacitor elements are connected in series, each of which is formed by press-molding tantalum powder on one side of tantalum foil, sintering it, and sequentially forming an oxide film, a semiconductor layer, and a conductor layer. Chip type solid electrolytic tantalum capacitor.