JPH06333788A - Structure and manufacture of surface-mount solid-state electrolytic capacitor - Google Patents

Abstract

PURPOSE:To reduce the size and the weight of a solid state electrolytic capacitor such as a tantalum solid-state electrolytic capacitor while the capacity is maintained large and to form the whole body into nearly a rectangular parallelopiped. CONSTITUTION:A tantalum pentoxide dielectric film, a manganese dioxide solid-state electrolyte layer, and a cathode film are formed on a chip piece 11 which is made by sintering metal particles such as tantalum particles into porous material. A pair of right and left metal-made anode terminal pieces 16a', 16b' are fixed on an anode bar 13 which is formed integral with the chip piece 11 and jets out from the chip piece 11 so as to hold the anode bar between them. One end face of these anode terminal pieces which is on the opposite side of the chip piece is formed into anode terminal faces 16a'', 16b'' which are nearly at a right angle to an axis of the anode bar. On the other hand, one end face of the chip piece which is on the opposite side of the anode bar is formed into a cathode terminal face 11a which is nearly at a right angle to the axis of the anode bar. Then, the whole external face of the device except for the anode terminal faces 16a'', 16b'' and the cathode terminal face 11a are packaged with a film 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a surface mounting type solid electrolytic capacitor such as a tantalum solid electrolytic capacitor or an aluminum solid electrolytic capacitor which has a small size and a large capacity, and a surface mounting type solid electrolytic capacitor. It is about the method.

[0002]

2. Description of the Related Art Conventionally, a capacitor element 1 in a solid electrolytic capacitor of this type is manufactured by the method described below. First, the metal particles such as tantalum are shown in FIG.
As shown in FIG. 6, the porous tip piece 2 is sintered and the anode rod 3 made of metal such as tantalum is integrally fixed to the tip piece 2.

As shown in FIG. 17, this chip piece 2 is
A direct current is applied in a state of being immersed in a chemical conversion solution such as phosphoric acid aqueous solution A to carry out anodization to form a dielectric film such as tantalum pentoxide 4 on the surface of each metal particle in the chip piece 2. In this case, the chip piece 2 is replaced with the phosphoric acid aqueous solution A.
By immersing the chip piece 2 in such a manner that the upper surface of the chip piece 2 is appropriately submerged by a depth H from the liquid surface of the chemical solution such as the phosphoric acid aqueous solution A, the outer peripheral surface of the root portion of the anode rod 3 Also, similarly, a dielectric film of tantalum pentoxide 4a or the like is appropriately formed over a portion having a length H.

Next, the chip piece 2 after completing the step of forming the dielectric film such as the tantalum pentoxide 4, 4a is
As shown in FIG. 18, for the manganese nitrate aqueous solution B,
By dipping until the upper surface of the chip piece 2 does not become lower than the liquid surface of the manganese nitrate aqueous solution B, permeating the manganese nitrate aqueous solution B into the inside of the chip piece 2, and then lifting and firing, repeating the above a plurality of times. A solid electrolyte layer formed of a metal oxide such as manganese dioxide 5 is formed on the surface of a dielectric film such as tantalum pentoxide 4, or a solid electrolyte layer formed of an organic semiconductor film is formed on the surface of the dielectric film such as tantalum pentoxide 4. Are formed by a chemical polymerization method, an electrolytic oxidative polymerization method, or a gas phase polymerization method.

Further, the capacitor element 1 is configured by forming a cathode film made of metal such as silver or nickel on the entire outer peripheral surface of the chip piece 2 excluding the upper surface through a graphat film or the like. There is. That is, the capacitor element 1 in the conventional solid electrolytic capacitor
When the dielectric film 4 such as tantalum pentoxide is formed on the surface of the metal particles in the chip piece 2, the outer peripheral surface of the root portion of the anode rod 3 fixed to the chip piece 2 is
By forming the dielectric film such as tantalum pentoxide 4a so as to be continuous with the dielectric film such as tantalum pentoxide 4 formed on the surface of the metal particles, the dielectric film such as tantalum pentoxide 4a is formed. The anode side of the anode rod 3 and the cathode side of the solid electrolyte layer such as manganese dioxide 5 are isolated (insulated).

For this reason, in the conventional solid electrolytic capacitor, the anode rod 3 protruding from the chip piece 2 cannot be cut off from the root portion thereof. Therefore, in the case of the conventional surface mount type solid electrolytic capacitor, For example,
Japanese Patent Publication No. 3-30977, and FIG.
As shown in FIG.
Is fixed to one lead terminal 6b of the pair of left and right lead terminals 6a and 6b, and the anode rod 3 protruding from the chip piece 2 is fixed to the other lead terminal 6a.
The structure is such that packaging is performed by the synthetic resin mold portion 7, or, as shown in FIG. 20, the portion of the capacitor element 1 excluding the bottom surface of the chip piece 2 and the tip of the anode rod 3 is made of synthetic resin or the like. The package is made of a covering material 8 and the cathode terminal portion 9 is formed on the bottom surface of the chip piece 2 by soldering.
b on the tip of the anode rod 3 by soldering to the anode terminal portion 9a
Are formed respectively.

[0007]

However, in the surface mount type solid electrolytic capacitor of the form shown in FIG. 19, the entire capacitor element 1 and a part of both lead terminals 6a and 6b are
Since the structure is such that the capacitor 7 is packaged in the synthetic resin mold portion 7, the overall size of the capacitor element 2 is large, so that the volume efficiency is low and the capacitor element 2 is large in size.

Moreover, when packaged by the synthetic resin mold part 7, a large stress often acts on the chip piece 2 to increase the leakage current (LC) or cause a short circuit defect. And in other words,
Since the defective rate is high, the yield rate at the time of manufacturing is low. Moreover, the synthetic resin mold portion 7 is formed, both lead terminals 6a and 6b are bent, and the chip piece 2 and the anode rod 3 are leaded. Since it is necessary to fix the terminals 6a and 6b and the like, the manufacturing process is complicated, and the material cost for both the lead terminals 6a and 6b and the molding portion 7 is considerably increased, so that the yield rate in manufacturing is low as described above. Combined with this, there was a problem that the manufacturing cost would increase significantly.

On the other hand, the surface mount type solid electrolytic capacitor of the form shown in FIG. 20 has an advantage that the volume efficiency can be made higher than the former. However, on the other hand, the tip of the tantalum anode rod 3 is soldered to the anode terminal portion 9
When providing a, solder cannot be directly applied to the tantalum anode rod 3, so the tip of the tantalum anode rod 3 is once metal-plated with nickel or the like, and the metal plating layer is In order to apply the metal plating only to the tip of the thin anode rod 3, a complicated process such as preventing the plating solution from penetrating into the chip piece 2 is required. Therefore, the cost is significantly increased, and furthermore, the anode terminal portion 9 formed by soldering on the tip portion of the anode rod 3 is used.
Since a has a sharp shape as shown in FIG. 20, the shape of the entire surface-mounting solid electrolytic capacitor cannot be made into a rectangular parallelepiped, so that the commercial value is low and a vacuum is applied to the printed circuit board. In the case of automatically mounting by the suction type collet, there is a problem that the positioning accuracy of the mounting is low and the alignment by the parts feeder or the like is difficult.

It is a technical object of the present invention to provide a structure of a solid electrolytic capacitor capable of solving these problems and a manufacturing method thereof.

[0011]

In order to achieve this technical object, the solid electrolytic capacitor according to the present invention has a structure in which a chip piece obtained by sintering metal particles such as tantalum into a porous film is provided with a dielectric film such as tantalum pentoxide. , A solid electrolyte layer such as manganese dioxide and a cathode film are respectively formed, and a pair of left and right metal anode terminal pieces are attached to an anode rod integrally protruding from the tip piece.
The anode rods are fixed so as to sandwich the anode rod with the anode rods, and one end face of the anode rods opposite to the tip strip is formed on the anode pin face substantially perpendicular to the axis of the anode rod. An end surface of the chip piece on the side opposite to the anode rod is formed on a cathode terminal surface substantially perpendicular to the axis of the anode rod, and further, a portion excluding the anode terminal surface and the cathode terminal surface,
Package with coating film. "."

Further, the manufacturing method of the present invention is an anode rod in which a plurality of chip pieces obtained by sintering metal particles such as tantalum into a porous body are integrally projected with respect to a horizontal bar from the respective chip pieces. By attaching the at a suitable pitch interval in the longitudinal direction of the horizontal bar, in this state, forming a dielectric film such as tantalum pentoxide for each chip piece,
Including a step of forming a solid electrolyte layer such as manganese dioxide and a cathode film and a step of forming a cathode film, further, a pair of metal rods extending along a horizontal bar to the anode rod in each of the chip pieces, the metal A step of sticking each anode rod so as to sandwich each anode rod, a step of cutting the both metal rods into anode terminal pieces for each anode rod, and a tip of the tip piece on the side opposite to the anode rod and the tip of the anode rod. The method is characterized by including a step of forming a coating film on a portion excluding the end surface on the side opposite to the piece and a step of cutting each of the anode rods at the end surface of the anode terminal piece. It is something.

[0013]

[Operation] With this structure, the portion other than the anode terminal surface and the cathode terminal surface is packaged by the coating film, but the entire shape is substantially rectangular parallelepiped, and the metal at one end is formed. The anode terminal surface of the manufactured anode terminal piece and the cathode terminal surface at the other end surface can be formed substantially parallel to each other.

[0014]

As described above, according to the present invention, the solid electrolytic capacitor is provided with the anode terminal surface and the cathode terminal surface, which are substantially parallel to each other, on both left and right end surfaces without packaging the solid electrolytic capacitor in the molded portion made of synthetic resin. Since it can be made into a substantially rectangular parallelepiped, it is possible to significantly reduce the size and weight as compared with the conventional one shown in FIG. 19, while the product value is higher than that of the conventional one shown in FIG. Not only can this be greatly improved, but also the positioning accuracy in automatic mounting on the printed circuit board can be improved, and since it is not necessary to plate the thin anode rod protruding from the chip piece with metal such as nickel, the manufacturing cost is greatly reduced. It can be reduced to

In particular, according to the manufacturing method of the present invention, it is possible to fix the anode terminal piece to the anode rod protruding from the chip piece simultaneously for a plurality of chip pieces, which is suitable for mass production. It has the effect of further reducing the cost.

[0016]

Embodiments of the present invention will be described below with reference to the drawings (FIGS. 1 to 12) for manufacturing a tantalum solid electrolytic capacitor. First, as shown in FIG. 1, a plurality of chip pieces 11 made by sintering tantalum particles into a porous body are made of tantalum and integrally protruded from the respective chip pieces 11 with respect to the horizontal bar 12. By fixing the anode rods 13 by welding, they are mounted along the longitudinal direction of the horizontal bar 12 at appropriate pitch intervals.

Each chip piece 11 mounted on the horizontal bar 12 as described above is immersed in phosphoric acid aqueous solution A as shown in FIG. A dielectric film of tantalum pentoxide 14 is formed on the surface of each tantalum particle in the chip piece 11. next,
As shown in FIG. 3, each of the chip pieces 11 on which the step of forming the dielectric film of the tantalum pentoxide 14 has been completed as described above is subjected to the manganese nitrate aqueous solution B, and By dipping only the lower part on the upper surface, permeating the manganese nitrate aqueous solution B into the inside of each chip piece 11, and then lifting and baking the same, the tantalum pentoxide 14 in each chip piece 11 is repeated. After the solid electrolyte layer of manganese dioxide 15 is formed on the surface of the dielectric film of No. 3, silver, palladium, nickel or solder is applied to the entire surface of each chip piece 11 except its upper surface through the graphat film. To form a cathode base film.

Then, as shown in FIGS. 4 and 5, a first metal rod 16a extending along the horizontal bar 12 is welded or crimped to one side surface of the anode rod 13 projecting from each of the chip pieces 11. 6 and 7, the second metal rod 16b extending along the horizontal bar 12 is welded or welded to the other side surface of the anode rod 13 protruding from each chip piece 11 as well. It is fixed with a conductive adhesive or the like.

That is, a pair of two metal rods 1 extending along the horizontal bar 12 is provided on the anode rod 13 of each chip piece 11.
6a and 16b are fixed so as to sandwich the anode rod 13 between the metal rods 16a and 16b. Next, the metal rods 16a and 16b are cut with a cutter or the like at a portion between the anode rods 13 so that the anode terminal pieces 16a 'fixed to the anode rods 13 are fixed as shown in FIG. , 1
6b 'is divided into two pieces, and both anode terminal pieces 16a', 1
The upper surface of 6b 'is formed into anode terminal surfaces 16a "and 16b" which are substantially perpendicular to the axis of the anode rod 13, while the bottom surface of each chip piece 11 is substantially perpendicular to the axis of the anode rod 13. It is formed on the negative cathode terminal surface 11a.

Next, in each of the chip pieces 11, as shown in FIGS. 9 and 10, an insulating material 17 such as synthetic resin or glass is provided between the upper surface of the chip piece 11 and both anode terminal pieces 16a ', 16b'. And then the anode terminal surface 16
As shown in FIGS. 11 and 12, a coating film 18 made of synthetic resin or glass is applied to the outer surfaces excluding a ″, 16b ″ and the cathode terminal surface 11a (this coating film 18 May be applied after cutting the anode rod 13 described later).

Then, as shown in FIG. 12, each of the anode rods 13 is cut by a rotary cutter 19 or the like on the same surface as the anode terminal surfaces 16a "and 16b", so that the horizontal bar 12 is cut. The tantalum solid electrolytic capacitor 20 as shown in FIGS. 13 to 15 can be manufactured. That is, this tantalum solid electrolytic capacitor 20 has a chip piece 11 obtained by porously sintering metal particles such as tantalum.
A tantalum pentoxide dielectric film 14, a manganese dioxide solid electrolyte layer 15 and a cathode film are formed on the chip piece 1 respectively.
1. A pair of left and right metal anode terminal pieces 16a ', 16b' are fixed to the anode rod 13 integrally protruding from 1 so that the anode rod 13 is sandwiched between the anode terminal pieces 16a ', 16b'. One end surface of each of the anode terminal pieces 16a ', 16b' opposite to the tip piece 11 is formed on the anode terminal surfaces 16a ", 16b" substantially perpendicular to the axis of the anode rod 13, while The end surface on the side opposite to the anode rod 13 has a cathode terminal surface 11 substantially perpendicular to the axis of the anode rod 13.
a, and further the anode terminal surfaces 16a ″, 16b ″
Also, the portion other than the cathode terminal surface 11a is packaged with the coating film 18.

Incidentally, the anode terminal surfaces 16a ", 16b"
Also, solder films 21 and 22 may be formed on the cathode terminal surface 11a as shown by the chain double-dashed lines in FIGS. 14 and 15, and the anode terminal pieces 16a 'and 16 may be formed.
One or both of b'is made of a magnetic metal such as carbon steel and magnetized to align the tantalum solid electrolytic capacitor 20 with its anode side constantly, and There is an advantage that identification can be performed easily and surely.

Further, although the above-mentioned embodiment is the case of the tantalum solid electrolytic capacitor, the present invention is not limited to this, but it is needless to say that the present invention can be applied to other solid electrolytic capacitors such as an aluminum solid electrolytic capacitor. Yes.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which a plurality of chip pieces are attached to a horizontal bar in the method of the present invention.

FIG. 2 is a cross-sectional view showing a state in which a process of forming a tantalum pentoxide dielectric film on the chip piece in FIG. 1 is being performed.

FIG. 3 is a cross-sectional view showing a state in which a treatment for forming a solid electrolyte layer of manganese dioxide is performed on the chip piece in FIG.

FIG. 4 is a perspective view showing a state where a first metal rod is fixed to the anode rod of each chip piece in FIG.

5 is a sectional view taken along line VV of FIG.

FIG. 6 is a perspective view showing a state where a second metal rod is fixed to the anode rod of each chip piece in FIG.

7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a perspective view showing a state in which the metal rods are cut into anode terminal pieces for each chip piece.

FIG. 9 is a perspective view showing a state in which an insulating material is applied to each chip piece.

10 is a cross-sectional view taken along line XX of FIG.

FIG. 11 is a perspective view showing a state in which a coating film for each chip piece is formed.

FIG. 12 is a sectional view taken along line XII-XII in FIG. 11, showing a state in which the anode rod in each chip piece is cut.

FIG. 13 is a perspective view of a manufactured tantalum solid electrolytic capacitor.

14 is a sectional view taken along line XIV-XIV of FIG.

15 is a sectional view taken along line XV-XV of FIG.

FIG. 16 is a perspective view of a chip piece used in a conventional manufacturing method.

FIG. 17 is a cross-sectional view showing a state in which a process of forming a tantalum pentoxide dielectric film on the chip piece in FIG. 16 is being performed.

FIG. 18 is a cross-sectional view showing a state where a process for forming a solid electrolyte layer of manganese dioxide is performed on the chip piece in FIG.

FIG. 19 is a vertical sectional front view showing a conventional tantalum solid electrolytic capacitor.

FIG. 20 is a vertical sectional front view showing another conventional tantalum solid electrolytic capacitor.

[Explanation of symbols]

11 Chip Piece 12 Horizontal Bar 13 Anode Rod 14 Tantalum Pentoxide Dielectric Film 15 Manganese Dioxide Solid Electrolyte Layer 16a, 16b Metal Rods 16a ′, 16b ′ Anode Terminal Pieces 16a ″, 16b ″ Anode Terminal Surface 11a Cathode Terminal Surface 17 Insulating material 18 Coating film 20 Tantalum solid electrolytic capacitor

Claims (2)

[Claims] 1. A chip piece obtained by porously sintering metal particles such as tantalum and a dielectric film such as tantalum pentoxide, a solid electrolyte layer such as manganese dioxide, and a cathode film are formed on the chip piece, and the chip piece is integrated. A pair of left and right metal anode terminal pieces are fixed to the positively protruding anode rod so that the anode rod is sandwiched between the both anode terminal pieces, and one end surface of the both anode terminal pieces on the side opposite to the chip piece is fixed. , The end surface of the tip piece on the side opposite to the anode rod is formed on the cathode terminal surface substantially perpendicular to the axis of the anode rod, and the anode terminal surface is formed at a right angle to the axis of the anode rod. A structure of a surface mounting type solid electrolytic capacitor, characterized in that a portion excluding the terminal surface and the cathode terminal surface is packaged with a coating film. 2. A plurality of chip pieces obtained by sintering metal particles such as tantalum into a porous body are fixed to a horizontal bar by an anode rod integrally protruding from each of the chip pieces.
Mounted at appropriate pitch intervals in the longitudinal direction of the horizontal bar, in this state, a step of forming a dielectric film such as tantalum pentoxide for each chip piece, a step of forming a solid electrolyte layer and a cathode film such as manganese dioxide and Including a step of forming a cathode film, further, a step of fixing two pairs of metal rods extending along the horizontal bar to the anode rods in each of the chip pieces so as to sandwich each anode rod with the both metal rods, A step of cutting both the metal rods into anode terminal pieces for each anode rod, and covering a portion excluding the end surface of the tip piece opposite to the anode rod and the end surface of the anode rod opposite to the tip piece. A method for manufacturing a surface-mounted solid electrolytic capacitor, comprising: a step of forming a film; and a step of cutting each of the anode rods at an end face of an anode terminal piece.