JP3515329B2 - Chip-shaped electronic component and manufacturing method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-shaped electronic component such as a chip-shaped capacitor, a chip-shaped resistor and a chip-shaped coil, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In the chip-shaped electronic component, an electronic component element (4) is housed in a molding die (100) as shown in FIG.
In the cavity (102) formed between the electronic component element (4) and the molding die (100), the molten resin is applied at high pressure from the gate (101) (inlet of the molten resin) leading to the cavity (102). And the electronic component element (4) is covered with resin to form an outer shell. In this type of outer shell resin molding, transfer molding is carried out when a thermosetting resin is used, and injection molding is carried out when a thermoplastic resin is used. Injection molding generally refers to injection molding, but transfer molding is also considered to be a type of injection molding. Therefore, in the present application, injection molding includes both transfer molding and injection molding.

The injection pressure of the molten resin in the above injection molding is large, and the mechanical shock at this time may impair the function of the electronic component. This problem will be described when the electronic component is a solid electrolytic capacitor. The capacitor element (40) corresponding to the electronic component element (4) in the solid electrolytic capacitor is formed by a valve metal such as Ta (tantalum), Al (aluminum), Nb (niobium) as shown in FIG. A dielectric oxide film (12) is formed on the surface of the element member (1) by using the element member (1) to be formed as an anode, and MnO ₂ , a conductive organic material or the like is formed on the dielectric oxide film (12). A solid conductive material (2) is used to form a cathode, and a carbon and silver paste layer (3) is formed on the cathode. The chip solid electrolytic capacitor is shown in FIG.
Like the anode lead wire (11) of the capacitor element (40)
And carbon and silver paste layer (3) on metal terminal board (6) (6
1) is attached and by injection molding, the capacitor element (40)
And a part of the metal terminal boards (6) (61) are covered with resin,
Form the outer shell (9), bend the metal terminal plates (6) (61) exposed from the outer shell (9) along the outer shell (9), and then perform aging treatment. Is completed by.
In the manufacture of the above solid electrolytic capacitor, the dielectric oxide film on the valve metal surface is damaged by the mechanical shock caused by the injection pressure of the resin when the capacitor element is coated with the resin for forming the outer shell, which may be the cause of leakage. An increase in current occurs.

Several methods have been proposed to reduce the mechanical shock. As one of the methods, there has been proposed a method of reducing the injection pressure of the molten resin in injection molding. However, with this method, the effect of alleviating the mechanical shock is small, and it is not possible to prevent damage to the electronic component element. Further, the molten resin cannot sufficiently flow into the molding die, resulting in the formation of a large number of electronic components having incomplete reliability of the resin coating. Further, as shown in FIGS. 6 and 7, before forming the outer shell (9), a resin liquid such as an epoxy resin liquid or a silicone resin liquid is applied to the entire surface of the electronic component element (4) to be solidified, A method of forming a coating layer (8) of elastic resin has been proposed. According to this method, since the elastic resin coating layer (8) effectively absorbs the mechanical shock, damage to the electronic component element (4) can be effectively prevented. However,
In this method, since the thickness of the coating layer (8) is increased, the chip-shaped electronic component including the thickness of the outer shell (9) is increased. Furthermore, in injection molding, coating layer (8)
Due to the thickness of the resin, the molten resin cannot fully flow into the molding die, and the coating layer (8) protrudes from the outer shell (9), resulting in the formation of a large number of electronic components having reliability problems. .

[0005]

Further, instead of applying the resin on the entire surface of the electronic component element (4) as described above,
A method of applying a resin to a part of the surface of the electronic component element (4) has been proposed. In this case, the resin is mainly applied to the surface of the electronic component element (4) close to the gate (101), for example, in the case of FIG. 8, the extraction surface (41) of the anode lead wire (11). Become. This is because the surface receives the injection pressure of the molten resin and becomes the surface having the largest mechanical shock. According to this method, similar to the method of applying resin on the entire surface of the electronic component element (4), not only the damage of the electronic component element (4) can be effectively prevented but also the electronic component unlike the above method. Since the resin is applied to a part of the surface of the element (4), there is no need to upsize the chip-shaped electronic component.
Since the resin is applied only to the surface of the electronic component element (4) close to the gate (101), the molten resin sufficiently flows into the molding die during injection molding, and the electronic component element (4) is surrounded by the outer shell (9).
It is possible to form a highly reliable electronic component completely covered with. According to this method, the gate (1
It is necessary not only to apply an amount of resin that alleviates the mechanical shock to the surface close to 01), but also to apply the resin accurately so as not to stick out from the surface. This is because when the resin is applied outside the surface, the molten resin cannot sufficiently flow into the molding die during injection molding, the resin coating of the electronic component element (4) becomes incomplete, or the applied resin The reason for this is that it will protrude from the outer shell (9), resulting in the formation of an electronic component having a problem with reliability. However,
Since the electronic component element (4) is small, it is difficult to perform the resin coating operation accurately. Therefore, this work must be performed manually by a skilled person, and is extremely inefficient.

The applicant of the present invention, as shown in FIG.
Of the surface of the electronic component element (4), a cushioning material (52) made of synthetic resin, rubber, paper, cloth or the like is applied only to the surface of the molding die (100) facing the gate (101). A method for reducing mechanical shock due to the injection pressure of molten resin has been proposed (Japanese Patent Laid-Open No. 8-148392). This method is effective in alleviating the mechanical shock, but after further study,
It was found that (52) should be accurately mounted on the facing surface of the electronic component element (4) so as not to protrude from the facing surface, and there is a problem in workability as in the above resin coating work. I knew it was.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a chip-shaped electronic component capable of reducing mechanical shock caused by injection pressure of a molten resin for forming an outer shell without impairing workability, and a manufacturing method thereof.

[0008]

According to the method of manufacturing a chip-shaped electronic component of the present invention, a resin body made of a thermosetting resin is provided on the surface of the electronic component element facing the gate of the molding die. Then, by heating and melting and curing the resin body,
A buffer body is formed on the facing surface, and an outer shell is formed on the electronic component element and the buffer body by injection molding.

[0009]

According to the present invention, when a resin body made of a thermosetting resin is heated, the resin body melts and spreads over the facing surface to cover the facing surface, and then hardens to form a buffer. At this time, the buffer body can be formed without protruding from the facing surface by appropriately adjusting parameters such as time and temperature for melting and curing. Also,
When the resin body is melted by heating, the resin body spreads over the facing surface and covers the facing surface. Therefore, it is not necessary to accurately attach the resin body to the facing surface. Therefore, this work can be automated without manual work, and as a result, a highly reliable chip-shaped electronic component can be efficiently manufactured by the present invention.

Embodiments of the present invention will be described below. Although the present embodiment is a method for manufacturing a chip-shaped solid electrolytic capacitor, the present invention is not limited to the method for manufacturing a chip-shaped solid electrolytic capacitor and is also applicable to a method for manufacturing other chip-shaped electronic components. it can. In the solid electrolytic capacitor, the capacitor element (40) is
A valve metal (10) is formed by electrolytic oxidation using the element member (1) made of a valve metal such as Ta, Al, Nb as an anode.
A dielectric oxide film (12) is formed on the surface of, and a cathode is formed on the dielectric oxide film (12) by using a solid conductive material (2) such as MnO _{2 or} a conductive organic material. A carbon and silver paste layer (3) is formed on the cathode. As shown in FIG. 4, the chip solid electrolytic capacitor of the present embodiment has
Metal terminal plates (6) and (61) are attached to the lead wire (11) of the capacitor element (40) and the carbon and silver paste layer (3), respectively, and the capacitor element (40) and the buffer body (5) are formed by injection molding.
1) and a part of the metal terminal board (6) (61) are covered with resin to form an outer shell (9), and the metal terminal board (6) (61) exposed from the outer shell (9). ) Is bent along the outer shell (9), and then an aging treatment is performed to complete. In the following examples, the Ta sintered body (10) is used for the anode, the polypyrrole (20) which is a conductive polymer is used for the cathode, and the buffer body (51) is made of the material. Although any thermosetting resin can be used, an epoxy resin is used as a typical thermosetting resin in the following examples. Further, as the resin body (5) which becomes the buffer body (51) by thermosetting, any shape such as a plate shape can be used, but in the following examples, a ring shape which is easily inserted into the anode lead wire is used. used.

[0011]

EXAMPLES Examples of the present invention and comparative examples will be described below.

(Embodiment 1) First, as shown in FIG.
a Sintered body (10) and lead wire (11) pulled out from the inside
A ring-shaped resin body (5) was inserted into the lead wire (11) of the element member (1) constituted by. The resin body
(5) is an epoxy resin and has a weight of about 1 mg. In the element member (1) provided with the resin body (5), the ends of the lead wires (11) are adhered to the carrier bar (7), and the carrier member (7) conveys the element member (1) to the manufacturing process of the solid electrolytic capacitor.

The element member (1) was immersed in an aqueous solution of H ₃ PO ₄ (phosphoric acid) and electrolytically oxidized to form a dielectric oxide film (12) around the element member (1). Next, element member
By holding (1) in a constant temperature bath at 150 ° C for 30 minutes, the resin body (5) melts and spreads on the lead-out surface (41) of the anode lead wire (11) in the element member (1), and then Cure
A buffer body (51) was formed on the extraction surface (41). Then, the element member is formed by using a well-known chemical polymerization method, electrolytic polymerization method, or the like.
A polypyrrole film (20) is formed on the dielectric oxide film (12) of (1), and a carbon and silver paste layer (3) is formed on the polypyrrole film (20) to form a capacitor element (40). Completed The completed capacitor element (40) is transported to the electronic component manufacturing process.

Metal terminal plates (6) and (61) were connected to the lead wire (11) of the capacitor element (40) and the lower surface of the capacitor element (40) by welding or bonding. Next, the metal terminal board (6) (6
The capacitor element (40) to which 1) is connected is set in the molding die (100). At this time, the capacitor element (40) is a buffer
The (51) is set so as to face the gate (101) of the molding die (100). Then, under conditions of a temperature of 175 ° C. and an injection pressure of 35 kg / cm ² , an epoxy resin was injection-molded in the molding die (100) to form an outer shell (9). Then, as shown in FIG.
Attach the metal terminal plates (6) (61) protruding from the outer shell (9) to the outer shell (9).
The chip-shaped solid electrolytic capacitor was completed by bending it along the line and aging it at a temperature of 125 ° C. for 2 hours.

(Embodiment 2) Embodiment 2 is different from Embodiment 1 in the order of forming the buffer body (51). First, in the same manner as in Example 1, an element member (1) composed of a Ta sintered body (10) and a lead wire (11) drawn from the inside thereof.
Was electrolytically oxidized in a H ₃ PO ₄ aqueous solution to form a dielectric oxide film (12) around the element member (1). Next, a polypyrrole film (20) is formed on the dielectric oxide film (12) of the element member (1) by using a well-known chemical polymerization method, electrolytic polymerization method, or the like, and the polypyrrole film (20) is formed. , Carbon and silver paste layers
(3) was formed to complete the capacitor element (40). After forming the capacitor element (40) in the above process, the ring-shaped resin body (5) was inserted into the lead wire (11) as shown in FIG. Next, metal terminal plates (6) and (61) were connected to the lead wire (11) of the capacitor element (40) and the lower surface of the capacitor element (40) by welding or bonding. Then, the capacitor element (40)
By keeping it in a constant temperature bath at 150 ° C for 30 minutes,
(5) is the anode lead wire (11) in the capacitor element (40)
It was melted and spread on the pull-out surface (41) and then hardened to form a buffer (51) on the pull-out surface (41).

In the following steps, the capacitor element (40) is formed in the molding die (100) so that the buffer body (51) faces the gate (101) of the molding die (100) in the same manner as in the first embodiment. ), And mold under the conditions of temperature 175 ℃ and injection pressure 35kg / cm ^2.
An epoxy resin was injection-molded in (100) to form an outer shell (9). Then, as shown in FIG. 4, the metal terminal plates (6) and (61) protruding from the outer shell (9) are bent along the outer shell (9),
Aging was performed by applying a voltage at a temperature of 125 ° C. for 2 hours to complete a solid electrolytic capacitor.

(Comparative Example 1) In Comparative Example 1, the ring-shaped resin body (5) is used as a lead wire as compared with the above-mentioned Examples 1 and 2.
The only difference is that it is not inserted into (11) and the buffer body (51) is not formed (FIG. 8). Mold the completed capacitor element (40)
00), and under conditions of a temperature of 175 ° C. and an injection pressure of 35 kg / cm ² , an epoxy resin was injection-molded in a molding die (100) to form an outer shell (9).

(Comparative Example 2) Comparative Example 2 differs from Comparative Example 1 in the outer shell formation by injection molding, and the temperature is 175
The outer shell (9) was formed by injection-molding under conditions of low pressure of 15 ° C. and injection pressure of 15 kg / cm ² .

(Comparative Example 3) Comparative Example 3 is shown in FIGS.
In comparison with Comparative Example 1, the capacitor element (40)
The difference is that the whole is covered with an elastic silicone resin layer (8). In Comparative Example 3, a silicone resin solution was applied to the entire completed capacitor element (40), and the capacitor element (40) was held in a constant temperature bath at a temperature of 150 ° C. for 3 hours to solidify the silicone resin solution to obtain a capacitor. The surface of the device (40) was covered with the elastic silicone resin layer (8). And the temperature 175
An outer shell (9) was formed by injection molding under conditions of ℃ and injection pressure of 35 kg / cm ² . Table 1 shows the inspection results of the leakage current and the outer shell molding failure in the above-mentioned Examples and Comparative Examples.

[0020]

[Table 1]

From Table 1, the following can be understood. Looking at the results of Comparative Example 1, in order to alleviate the mechanical shock due to the injection pressure of the molten resin in the injection molding, there is no defective product without any measures, but there are very few non-defective products with small leakage current. . That is, it can be seen that the influence of the mechanical shock on electronic components cannot be ignored. Also, looking at the results of Comparative Example 2, the number of non-defective products having a small leakage current is larger than that of Comparative Example 1, but the total number (50) is still small, and the number of defective products is extremely large. That is, in the method of lowering the injection pressure of the molten resin, the effect of alleviating mechanical shock is small, and
It can be seen that the molten resin cannot fully flow into the molding die. Further, looking at the results of Comparative Example 3, although there are an extremely large number of non-defective products having a small leakage current, at the same time, there are also an extremely large number of defective products. That is, the method of covering the entire surface of the capacitor element (40) with the elastic silicone resin has a great effect of alleviating mechanical shock, but the molten resin cannot sufficiently flow into the molding die during injection molding. I understand.

Compared to Comparative Examples 1, 2, and 3, the results of Examples 1 and 2 show that there are many non-defective products with small leakage current and no defective products. That is, it can be seen that the method of the present embodiment has a large effect of alleviating mechanical shock, and that the molten resin sufficiently wraps around the inside of the molding die during injection molding. Also,
In the buffer (51) of the present embodiment, the resin body (5) having holes formed in the lead wire (11) is inserted, the resin body (5) is melted, and the resin body (5) is connected to the anode lead wire (11). Since the resin body (5) is formed by spreading it on the drawing surface (41) and curing it, it is not necessary to attach the resin body (5) to the drawing surface (41) accurately. Therefore, since the hole of the resin body (5) can be made sufficiently larger than the diameter of the lead wire as shown in FIG. 1, the insertion work becomes easy, and further, it can be automated without manual work. As a result, according to the present embodiment, a highly reliable chip solid electrolytic capacitor can be efficiently manufactured. In addition, both Example 1 and Example 2 can form a highly reliable chip solid electrolytic capacitor. Therefore, the disposition of the resin body (5) and the formation of the cushioning body (51) may be performed at any time before the outer shell (9) is formed by injection molding, and the entire extraction surface (41) is covered. Not considered necessary. From this, the drawer surface (4
A region of 1) that faces the gate (101) of the molding die (100) (a portion that intersects with the anode lead wire (11) in this embodiment).
However, since it is the region where the resin injection pressure is the largest, it is considered that the mechanical shock can be sufficiently mitigated and damage to the electronic component can be prevented by forming the buffer body (51) only in this region.

The above description of the embodiments is for explaining the present invention, and should not be construed to limit the invention described in the claims or to reduce the scope.
The configuration of each part of the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims. For example, in this embodiment, as shown in FIG. 8, the anode lead wire (11) in the capacitor element (40) is
The pull-out surface (41) of the molding die (100) faces the gate (101) of the molding die (100). Therefore, although the buffer body (51) is formed on the pull-out surface (41), other than the capacitor element (40). It goes without saying that the buffer body (51) is formed on the other surface if this surface faces the gate (101).

[Brief description of drawings]

FIG. 1 is an example 1 in which a ring-shaped resin body is arranged on an element member.
It is a perspective view showing the state.

FIG. 2 is a perspective view showing a state of a second embodiment in which a ring-shaped resin body is arranged on a capacitor element.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view showing a chip-shaped electronic component of the present invention.

FIG. 5 is a cross-sectional view showing a conventional chip-shaped electronic component using a cushioning material.

FIG. 6 is a perspective view of Comparative Example 3 in which a resin coating layer is formed on the entire surface of the electronic component element.

FIG. 7 is a cross-sectional view showing a conventional chip-shaped electronic component that has undergone the process of FIG.

FIG. 8 is a cross-sectional view showing a state in which an electronic component element is provided in a molding die in order to cover the electronic component element with an outer shell.

[Explanation of symbols]

(1) Element member (2) Solid conductive material layer (4) Electronic component element (5) Resin body (9) Outer shell (12) Dielectric oxide film (40) Capacitor element (51) Buffer (100) Mold (101) Gate

─────────────────────────────────────────────────── --Continued from the front page (56) References JP-A-8-148392 (JP, A) JP-A-55-83224 (JP, A) JP-A-3-292715 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01G 9/08 H01G 9/012 H01G 13/00 321

Claims (3)

(57) [Claims] 1. An element member (1) formed by a sintered body made of a valve metal such as Ta, Al, Nb and a lead wire (11) drawn out from the inside thereof is used as an anode, and the surface of the element member is formed. A dielectric oxide film (12) is formed on the dielectric oxide film (12), and a cathode is formed on the dielectric oxide film (12) using a solid conductive material (2) such as MnO _{2 or} a conductive organic semiconductor. On the other hand, in the method for producing a solid electrolytic capacitor in which a resin outer shell is formed by injection molding such as transfer molding or injection molding, a hole larger than the diameter of the lead wire (11) is formed in the lead wire (11). A resin body made of the thermosetting resin thus formed is inserted, and by heating and melting the resin body, it is spread on the lead-out surface (41) of the lead wire (11) and then cured to be buffered (51).
In addition, the extraction surface (41) on which the buffer body (51) is formed is disposed so as to face the gate (101) of the injection molding die (100) to form the capacitor element (40) and the buffer body (51). On the other hand, a method for manufacturing a solid electrolytic capacitor, characterized in that the outer shell (9) is formed by injection molding. 2. A dielectric oxide film (12) is formed, then a buffer (51) is formed, and then a cathode is formed using a solid conductive material (2). Item 2. A method for manufacturing a solid electrolytic capacitor as described in Item 1. 3. The method for producing a solid electrolytic capacitor according to claim 1, wherein the cathode is formed by using the solid conductive material (2), and then the buffer body (51) is formed.