JP2875452B2 - Manufacturing method of surface mount type 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 surface-mount 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.

[0002]

2. Description of the Related Art Conventionally, a capacitor element 1 in a solid electrolytic capacitor of this kind is manufactured by the following method. First, a metal particle such as tantalum is used in FIG.
As shown in FIG. 6, a porous chip piece 2 is sintered, and an anode rod 3 made of metal such as tantalum is integrally fixed to the chip piece 2.

[0003] As shown in FIG.
Anodizing is performed by applying a direct current while immersed in a chemical solution such as a phosphoric acid aqueous solution A 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
And so on, so that the upper surface of the chip piece 2 is immersed in a depth H as appropriate from the surface of the chemical solution such as the phosphoric acid aqueous solution A. Similarly, a dielectric film such as tantalum pentoxide 4a is formed over a portion having a length H as appropriate.

Next, the chip piece 2 which has completed the step of forming the dielectric film such as tantalum pentoxide 4, 4a is
As shown in FIG. 18, the manganese nitrate aqueous solution B
By repeatedly immersing the upper surface of the chip piece 2 until the upper surface of the chip piece 2 does not become lower than the liquid level of the manganese nitrate aqueous solution B, penetrating the manganese nitrate aqueous solution B into the inside of the chip piece 2 and then withdrawing and firing the same, a plurality of times are repeated. A solid electrolyte layer made 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 made of an organic semiconductor film is formed on the surface of the dielectric film such as tantalum pentoxide 4. Is formed by a chemical polymerization method, an electrolytic oxidation polymerization method, or a gas phase polymerization method.

Further, a metal cathode film such as silver or nickel is formed on the entire outer peripheral surface of the chip piece 2 except for the upper surface via a graphite film or the like so that the capacitor element 1 is constituted. I have. 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 base of the anode rod 3 fixed to the chip piece 2
By forming a 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 bar 3 is isolated (insulated) from the cathode side of the solid electrolyte layer such as manganese dioxide 5.

For this reason, in the conventional solid electrolytic capacitor, since the anode rod 3 protruding from the chip piece 2 cannot be cut off from the base thereof, in the case of the conventional surface mount type solid electrolytic capacitor, For example,
It is described in JP-B-3-30977 and FIG.
As shown in the figure, the capacitor element 1 is
Is fixed to one lead terminal 6b of a 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 package is configured to be packaged with a synthetic resin mold part 7, or as shown in FIG. 20, a 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 packaged with a covering material 8 and a cathode terminal portion 9 made of solder is provided on the bottom surface of the chip piece 2.
b is connected to the tip of the anode bar 3 by an anode terminal 9a made of solder.
Are formed respectively.

[0007]

However, in the surface mount type solid electrolytic capacitor shown in FIG. 19, the entire capacitor element 1 and a part of both lead terminals 6a and 6b are used.
Since the structure is such that the package is formed by the synthetic resin mold part 7, the overall size is larger than the size of the capacitor element 2, so that the volume efficiency is low and the size is larger than the capacity.

In addition, when a package is formed in the synthetic resin molded part 7, a large stress acts on the chip piece 2 so that the leakage current (LC) increases and a short-circuit defect frequently occurs. And in other words,
Since the reject rate is high, the yield rate at the time of manufacturing is low. In addition, the formation of the synthetic resin molded part 7, the bending of both lead terminals 6a, 6b, and the lead to the chip piece 2 and the anode rod 3 Since the terminals 6a and 6b need to be fixed and the like, the manufacturing process is complicated, and the material cost is considerably increased in both the lead terminals 6a and 6b and the mold portion 7, so that the yield rate in the manufacturing is low as described above. In conjunction with this, there has been a problem that the manufacturing cost is significantly increased.

On the other hand, the surface mount type solid electrolytic capacitor shown in FIG. 20 has an advantage that the volume efficiency can be increased as compared with the former. However, on the other hand, the anode terminal portion 9 made of solder is attached to the tip of the tantalum anode rod 3.
When a is provided, the solder cannot be directly applied to the tantalum anode rod 3, so that the tip of the tantalum anode rod 3 is once plated with metal such as nickel, In order to apply 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 the anode terminal portion 9 formed of solder is attached to the tip of the anode bar 3.
Since a has a sharp shape as shown in FIG. 20, the shape of the entire surface mount type solid electrolytic capacitor cannot be formed as a rectangular parallelepiped. In the case of automatic mounting using a suction type collet, there is a problem that not only the positioning accuracy of the mounting is low, but also it is difficult to align the components with a parts feeder or the like.

It is a technical object of the present invention to provide a method of manufacturing a solid electrolytic capacitor which can solve these problems.

[0011]

Means for Solving the Problems To achieve this technical problem
Therefore, the manufacturing method according to the present invention comprises the steps of: “fixing a plurality of chip pieces obtained by sintering metal particles such as tantalum to a porous bar, and fixing an anode rod integrally projecting from each chip piece to a horizontal bar. In this way, a step of forming a dielectric film such as tantalum pentoxide for each chip piece in this state, forming a solid electrolyte layer such as manganese dioxide and a cathode film in the longitudinal direction of the horizontal bar is performed. And a step of forming a cathode film, and furthermore, a pair of two metal rods extending along the horizontal bar is fixed to the anode rod of each of the chip pieces so as to sandwich each anode rod between the two metal rods. Process and
A step of cutting the two metal bars into anode terminal pieces for each anode bar, and then between the chip piece and each anode terminal piece.
After filling the insulating material, a step of forming a coating film on a portion of the chip piece other than the end face opposite to the anode bar and the tip piece and the end face of the anode bar on the opposite side; and Cutting at the end face of the anode terminal piece. It is.

[0012]

[Work] With this configuration, the entire shape is formed into a substantially rectangular parallelepiped, while the portion excluding the anode terminal surface and the cathode terminal surface is packaged with a coating film. The anode terminal surface formed by the anode terminal piece made of a metal and the cathode terminal surface at the other end surface can be formed substantially parallel to each other.

[0013]

As described above, according to the present invention, the solid electrolytic capacitor is provided with the anode terminal surface and the cathode terminal surface substantially parallel to each other on both left and right end surfaces without being packaged by the synthetic resin molded part. Manufactured in the form of a substantially rectangular parallelepiped
19, it is possible to significantly reduce the size and the weight with a large capacity as compared with the conventional one shown in FIG. 19, but it is possible to greatly improve the commercial value as compared with the conventional one shown in FIG. At the same time, the positioning accuracy during automatic mounting on a printed circuit board can be improved, and since there is no need to apply a metal plating such as nickel to the thin anode rod protruding from the chip piece, the manufacturing cost can be greatly reduced. is there.

In addition, according to the manufacturing method of the present invention, the anode terminal pieces can be fixed to the anode rod projecting from the chip pieces at the same time for a plurality of chip pieces. Effect that can reduce cost more
It also has fruit .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to drawings (FIGS. 1 to 12) for manufacturing a tantalum solid electrolytic capacitor. First, as shown in FIG. 1, a plurality of chip pieces 11 formed by porous sintering of tantalum particles are formed on a horizontal bar 12 by tantalum protruding integrally from the respective chip pieces 11. The anode bars 13 are fixed by welding so that they are mounted at appropriate intervals along the longitudinal direction of the horizontal bar 12.

Each of the chip pieces 11 mounted on the horizontal bar 12 as described above is immersed in a phosphoric acid aqueous solution A as shown in FIG. On the surface of each tantalum particle in the chip piece 11, a dielectric film of tantalum pentoxide 14 is formed. next,
As shown in FIG. 3, each of the chip pieces 11 having completed the step of forming the dielectric film of tantalum pentoxide 14 as described above, By immersing only the lower portion on the upper surface and infiltrating the aqueous solution of manganese nitrate B into the inside of each chip piece 11, and then withdrawing and firing a plurality of times, the tantalum pentoxide 14 in each of the chip pieces 11 is repeated. After a solid electrolyte layer of manganese dioxide 15 is formed on the surface of the dielectric film, silver, palladium, nickel or solder is interposed on the entire surface of each chip piece 11 except for the upper surface thereof through a graphite film. And the like.

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 protruding from each of the chip pieces 11. 6 and 7, the second metal rod 16b extending along the horizontal bar 12 is welded to the other side surface of the anode rod 13 projecting from each chip piece 11 by welding or the like. It is fixed by a conductive adhesive or the like.

That is, a pair of two metal bars 1 extending along the horizontal bar 12 is attached to the anode bar 13 of each chip piece 11.
6a and 16b are fixed so that each anode bar 13 is sandwiched between the two metal bars 16a and 16b. Next, the two metal bars 16a, 16b are cut by a cutter or the like at a portion between the anode bars 13 so that the anode terminal pieces 16a 'fixed to the anode bars 13 as shown in FIG. , 1
6b ', the anode terminal pieces 16a', 1
6b 'is formed on the anode terminal surfaces 16a "and 16b" 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. On the negative electrode terminal surface 11a.

Next, as shown in FIGS. 9 and 10, an insulating material 17 such as synthetic resin or glass is provided between the upper surface of each chip piece 11 and the anode terminal pieces 16a 'and 16b'. After coating and filled with the anode terminal surface 16a ", 16b" and against the outer surface except the cathode terminal surface 11a, 11 and 12, synthetic resin or glass coating film 18 (Note that the 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 on the same surface as the anode terminal surfaces 16a "and 16b" by a rotary cutter 19 or the like, so that the horizontal bar 12 is cut. , Whereby the tantalum solid electrolytic capacitor 20 as shown in FIGS. 13 to 15 can be manufactured. That is, the tantalum solid electrolytic capacitor 20 is provided with a chip piece 11 in which metal particles such as tantalum are sintered in a porous manner.
A dielectric film 14 of tantalum pentoxide, a solid electrolyte layer 15 of manganese dioxide and a cathode film are formed, respectively.
A pair of left and right metal anode terminal pieces 16a ', 16b' are fixed to the anode rod 13 integrally projecting from the anode rod 13 so that the anode rod 13 is sandwiched between the two anode terminal pieces 16a ', 16b'. One end faces of the anode terminal pieces 16a 'and 16b' on the opposite side to the chip piece 11 are formed on anode terminal faces 16a "and 16b" substantially perpendicular to the axis of the anode rod 13, while the chip piece 11 has The end face opposite to the anode rod 13 is connected to the cathode terminal surface 11 substantially perpendicular to the axis of the anode rod 13.
a, and a chip piece 11 and both anode terminal pieces 16
Insulation material such as synthetic resin or glass between a 'and 16b'
After applying and filling the material 17, the anode terminal surface 16
Portions other than a ", 16b" and the cathode terminal surface 11a are packaged with a coating film 18.

The anode terminal surfaces 16a ", 16b"
14 and 15, solder films 21 and 22 may be formed on the cathode terminal surface 11a, and the anode terminal pieces 16a 'and 16
One or both of b ′ are made of a magnetic metal such as carbon steel and magnetized, so that the tantalum solid electrolytic capacitor 20 can be aligned with its anode side fixed, and the polarity can be increased. There is an advantage that identification can be performed easily and reliably.

Further, the above embodiment is directed to a tantalum solid electrolytic capacitor. However, it goes without saying that the present invention is not limited to this and can be applied to other solid electrolytic capacitors such as aluminum solid electrolytic capacitors. No.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a state in which a plurality of chip pieces are mounted on a horizontal bar in a method according to 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 performed.

FIG. 3 is a cross-sectional view showing a state where a process of forming a solid electrolyte layer of manganese dioxide on the chip piece in FIG. 2 is performed.

FIG. 4 is a perspective view showing a state in which a first metal rod is fixed to an anode rod of each chip piece in FIG. 3;

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is a perspective view showing a state in which a second metal rod is fixed to an anode rod of each chip piece in FIG. 4;

FIG. 7 is a sectional view taken along the line VII-VII in FIG. 6;

FIG. 8 is a perspective view showing a state in which the two metal bars 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.

FIG. 10 is a sectional view taken along line XX of FIG. 9;

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

FIG. 12 is a sectional view taken along the line XII-XII of FIG. 11, showing a state in which an anode bar 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 the line XIV-XIV in FIG.

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

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

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 performed.

FIG. 18 is a cross-sectional view showing a state where a process of forming a solid electrolyte layer of manganese dioxide on the chip piece in FIG. 17 is performed.

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]

DESCRIPTION OF SYMBOLS 11 Chip piece 12 Horizontal bar 13 Anode rod 14 Dielectric film of tantalum pentoxide 15 Solid electrolyte layer of manganese dioxide 16a, 16b Metal rod 16a ', 16b' Anode terminal piece 16a ", 16b" Anode terminal surface 11a Cathode terminal surface 17 Insulation material 18 Coating film 20 Tantalum solid electrolytic capacitor

Claims (1)

(57) [Claims] 1. An anode rod integrally projecting from each chip piece is fixed to a plurality of chip pieces obtained by sintering metal particles such as tantalum or the like in a porous manner.
Attach at an appropriate pitch 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 such as manganese dioxide and a cathode film, and Including a step of forming a cathode film, further, fixing a pair of two metal rods extending along the horizontal bar to the anode bar in each of the chip pieces so as to sandwich each anode bar between the two metal bars, and cutting the two metal rods to the anode terminal piece for each anode rod, then the switch
Insulation material was filled between the tip piece and each anode terminal piece.
Chi, forming a coating film to the portion except for the end surface opposite the tip piece in anode rod opposite to the end surface and the anode rod in the chip pieces, the end faces of the respective anode rod anode terminal piece And a step of cutting the surface-mounted solid electrolytic capacitor.