JPH05175069A - Chip-shaped electronic component and its manufacture - Google Patents

Abstract

PURPOSE:To provide a chip-shaped electronic component which realizes a good mounting state on a printed-circuit board without changing the structure of an ordinary electronic component. CONSTITUTION:In a chip-shaped electronic component, an electronic component 1 is housed in an outer-package frame 2 which is provided with a housing space 4 which is adapted to the outward-appearance shape of the electronic component 1, and a lead wire 3 for the electronic component 1 is bent along the opening edge and the bottom face of the outer-package frame 2. In the chip-shaped electronic component, a corona discharge treatment is executed to one part on the surface of the outer-package frame 2, the surface is modified and, after that, a metal layer 7 which can be soldered is formed at the part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of electronic parts, and more particularly to a chip type electronic part suitable for surface mounting on a substrate.

[0002]

2. Description of the Related Art Conventionally, in order to realize electronic parts such as capacitors into chips, an electronic part element is subjected to resin molding, and a lead wire for external connection led out from a resin end face is bent along the side face of the resin. It was facing the wiring pattern on the printed circuit board.

Alternatively, for example, a device disclosed in Japanese Utility Model Publication No. 59-3557, in which conventional electronic components are housed in an outer frame and lead wires are arranged on substantially the same plane as the end face of the outer frame. Proposed. In addition, JP-A-60-
As in the inventions described in Japanese Patent Publication No. 245116 and Japanese Patent Laid-Open No. 60-245115, a capacitor is arranged in a cylindrical outer frame having a bottom, and a lead wire is led out from a through hole on the bottom surface of the outer frame. It has been proposed that the wire be bent so as to be housed in a recess provided on the outer surface of the exterior frame.

[0004]

However, in the chip-type electronic component to be molded, there is a risk that the electronic component element is thermally deteriorated due to the thermal stress during the molding process.

Further, as shown in FIG. 3, a chip-type electronic component 22 in which the electronic component body is housed in the exterior frame 2 and the lead wire 3 is led out from the end face of the exterior frame 2 and exposed to the printed circuit board 10. When soldered 11, this chip-type electronic component 2
Only the one end of the chip-type electronic component 22 is fixed to the printed circuit board 10 by the soldering 11. Therefore, the so-called tombstone phenomenon may occur in which the other end is lifted by the surface tension of the molten solder and the heat of the solder, or there is a case where the solder is separated from the printed circuit board 10 due to mechanical stress.

Further, with the recent miniaturization of electronic components, the distance between the lead wires led out from the electronic components has become extremely short and the dimensions thereof have become fine. Furthermore, the wiring pattern density of the printed circuit board has also increased, and the distance between various lead wires has been required for efficient placement. Therefore, it is necessary to hold the lead wires so as to correspond to the distances between various lead wires while ensuring an appropriate distance between the lead wires, that is, a distance that does not cause a short circuit due to solder. Has become.

Further, the tip portion of the lead wire facing the bottom surface of the outer frame tries to be restored to its original shape by "burring" due to so-called elastic force, and it is difficult to maintain an appropriate position and distance. .

An object of the present invention is to provide a chip-type electronic component which realizes a good mounting state on a printed circuit board without changing the structure of an ordinary electronic component.

[0009]

According to the present invention, an electronic component is housed in an outer frame having a housing space adapted to the external shape of the electronic component, and the lead wires of the electronic component are provided along the opening end face and the bottom face of the outer frame. In bent chip type electronic parts,
It is characterized in that after corona discharge is applied to a part of the surface of the outer frame to modify the surface of the outer frame, a solderable metal layer is formed on the part subjected to the corona discharge treatment.

Further, as a solderable metal layer formed on the surface of the exterior frame that has been subjected to corona discharge treatment, a solderable conductive paste or a solderable metal plate is attached via an adhesive. Is characterized by.

[0011]

As shown in the drawings, the lead wire 3 led out from the electronic component body (capacitor) 1 and the solderable metal layer (conductive paste 7) are provided on the surface of the outer frame 2, particularly the bottom surface. Will be placed. When mounting on a printed circuit board, the lead wire 3 and a metal layer (conductive paste 7) as an auxiliary terminal are soldered to each other so that both ends of the bottom surface of the chip type electronic component 20 are fixed to the printed circuit board by soldering. Will be done.

The metal layer (conductive paste 7) is formed on the surface 30 of the exterior frame 2 which has been subjected to corona discharge treatment, that is, surface modification treatment. By this corona discharge, the molecular chain on the surface 30 of the outer frame 2 made of synthetic resin or the like is cut, and at the cut portion, a carbonyl group, a carboxyl group, or the like is generated, and the polarity of the surface 30 is increased. The adhesion with the paste 7) is improved.

[0013]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a perspective view showing a chip-type electronic component according to an embodiment of the present invention from the bottom surface direction of an exterior frame, and FIG. 2 is a perspective view showing a second embodiment from the bottom surface direction of the exterior frame. In this embodiment, a capacitor will be described as an example of the electronic component.

The capacitor 1, which is an electronic component body, is formed by accommodating a capacitor element, which is formed by winding an electrode foil (not shown) and electrolytic paper, in a bottomed cylindrical outer case made of aluminum or the like. Then, as shown in FIG. 1, the lead wire 3 led from the capacitor element is led out from the end face of the capacitor 1.

Then, the capacitor 1 is housed in an exterior frame 2 having a cylindrical housing space 4 adapted to the external shape of the capacitor 1. It is desired that the exterior frame 2 is made of a material having excellent heat resistance, and preferably a heat resistant synthetic resin having excellent heat resistance such as epoxy, phenol, or polyimide is suitable.

The storage space 4 of the exterior frame 2 is formed in a cylindrical shape having an inner diameter substantially the same as the outer diameter of the capacitor 1 since the outer shape of the capacitor 1 is cylindrical in this embodiment. There is. When using a non-cylindrical capacitor or other electronic component, for example, an electronic component having an elliptical cross-sectional shape, an outer frame having an elliptic cylindrical storage space adapted to the shape is used.

The end surface of the capacitor 1 housed in the housing space 4 of the outer frame 2 abuts on the projection 5 formed on the open end surface of the outer frame 2, and the end surface of the capacitor 1 abutted on the projection 5 The lead wire 3 derived from the above is bent along the opening end surface and the bottom surface of the exterior frame 2 and is housed in the groove portion 6 provided on the bottom surface of the exterior frame 2. Therefore, the capacitor 1
The main body is fixed in the exterior frame 2 by the projecting portion 5 and the bent lead wire 3.

Then, a surface 3 of a part of the bottom surface of the exterior frame 2
No. 0 has been subjected to surface modification treatment in advance. In this surface modification treatment, the surface 30 of the exterior frame 2 has an output of 3 to 4 A
Corona discharge is performed for 30 seconds, and as a result, the outer frame 2
Surface 30 is activated. Then, after this surface modification treatment, the surface-modified surface 30 is coated with the conductive paste 7.

The conductive paste 7 is a solderable metal,
For example, metal particles of silver, tin, lead, zinc, nickel, iron, copper, or the like, mixed particles of these, or metal particles of an alloy thereof are mixed in a paste-like synthetic resin to generate. The synthetic resin mixed with metal particles, that is, the binder may be any, but a thermosetting synthetic resin having excellent heat resistance, for example, epoxy, phenol,
Preferred are diallyl phthalate, unsaturated polyester, polyimide, polyamide imide, polyamide bismaleimide and the like.

In this embodiment, the lead wire 3 led out from the body of the capacitor 1 and the conductive paste 7 formed on a part of the surface 30 subjected to the surface modification are exposed on the bottom surface of the exterior frame 2. . Therefore, when the chip-type electronic component 20 according to this embodiment is mounted on a printed circuit board, both ends of the chip-type electronic component 20 are fixed to the printed circuit board by soldering the lead wires 3 and the conductive paste 7 respectively. .

Twenty chip-type electronic components according to this example and 20 chip-type electronic components not subjected to surface modification treatment were prepared, and a conductive paste 7 containing copper particles mixed in a phenol resin binder was applied. Then, when the adhesive strength of each sample was compared, in the case where the surface modification treatment was not applied, the maximum value was 4.35 Kgf, the minimum value was 0.51 Kgf, and the average value was 2.16 Kgf, whereas corona discharge was performed. In the applied example, the maximum is 7.91 Kgf and the minimum is 3.3.
At 0 Kgf, the average value was 5.66 Kgf, and the adhesive strength was significantly improved.

Next, a second embodiment of the present invention shown in FIG. 2 will be described. As in the first embodiment, the capacitor 1 which is the main body of the electronic component has the lead wire 3 from the end face of the capacitor 1.
Are derived and formed. Similarly to the first embodiment, the outer frame 2 also has a storage space 4 for storing the capacitor 1 and a projection 5 on one end face of the opening. The lead wire 3 is bent along the bottom surface of the outer frame 2 from the end surface of the capacitor 1 and faces the bottom surface of the outer frame 2.

The surface of the outer frame 2 is previously surface-modified by corona discharge in the same manner as in the previous embodiment, and an adhesive is applied to the corona-discharge-treated portion. The metal piece 8 is arranged via an adhesive. Since the metal piece 8 is fixed by solder when mounted on a printed circuit board, a solderable metal such as silver, tin,
Lead, zinc, nickel, iron, copper or alloys thereof are preferable. Alternatively, a metal tape in which an adhesive is applied to one surface of the solderable thin-film metal piece may be used without applying the adhesive.

The chip-type electronic component 21 according to this embodiment is mounted on a printed board as in the first embodiment, and then the lead wire 3 and the metal piece 8 are soldered to each other.

Although the embodiment of the present invention has been described by taking the capacitor as an example, the present invention can be applied to other electronic components as long as they are electronic components that can be housed in the outer frame. Needless to say.

[0026]

As described above, according to the present invention, an electronic component is housed in an outer frame having a housing space adapted to the external shape of the electronic component, and the lead wires of the electronic component are provided along the opening end face and the bottom face of the outer frame. In a bent chip-type electronic component, a part of the surface of the outer frame is subjected to corona discharge treatment to modify the surface, and then a solderable metal layer is formed on the part subjected to this corona discharge treatment. Therefore, when the lead wire facing the printed board and the metal layer are soldered, the chip-type electronic component according to the present invention is fixed to the printed board at both ends of the bottom surface of the outer frame. Therefore, it is possible to prevent the chip-type electronic component mounted on the printed circuit board from floating or coming off from the printed circuit board due to vibration, soldering heat, “burr” of the lead wire, etc. as in the conventional case. Further, it becomes strong against mechanical stress when it is mounted on the printed board, the proper mounting state can be maintained, and the reliability is improved.

Since a strong metal layer can be formed on the surface of the outer frame only by performing corona discharge treatment at a desired position, the manufacturing process does not become complicated, and a large amount of surface modification is collectively performed. It becomes possible to perform quality treatment. Further, since the adhesive strength of the metal layer formed on the surface of the outer frame is improved, peeling of the metal layer due to solder heat, vibration, etc. does not occur even in surface mounting on the printed circuit board, and reliability is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a chip-type electronic component according to an embodiment from a bottom surface direction of an outer frame.

FIG. 2 is a perspective view showing a second embodiment from the bottom direction of the exterior frame.

FIG. 3 is a front view showing a conventional chip-type electronic component mounted on a printed circuit board.

[Explanation of symbols]

 1 Electronic Component Main Body (Capacitor) 2 Exterior Frame 3 Lead Wire 4 Storage Space 5 Protrusion 6 Groove 7 Conductive Paste 8 Metal Piece 10 Printed Circuit Board 11 Solder 20 Chip Electronic Component 21 Chip Electronic Component 22 Chip Electronic Component

Claims (3)

[Claims] 1. A chip-type electronic component in which an electronic component is stored in an outer frame having a storage space adapted to the external shape of the electronic component, and the lead wire of the electronic component is bent along the opening end surface and the bottom surface of the outer frame. A method for manufacturing a chip-type electronic component, which comprises subjecting a part of a surface of an outer frame to a corona discharge treatment, and then forming a solderable metal layer on the corona-discharged part. 2. The chip-type electronic component according to claim 1, wherein a solderable conductive paste is applied to a part of the surface of the exterior frame that has been subjected to corona discharge treatment. 3. The chip-type electronic component according to claim 1, wherein a solderable metal plate is adhered to a part of the surface of the outer frame subjected to the corona discharge treatment with an adhesive.