JPH08130364A - Mounting body of chip electronic part - Google Patents

Abstract

PURPOSE: To provide a chip electronic part mounting body which improves a chip electronic part in flexing properties to a board. CONSTITUTION: A layered ceramic capacitor 1 is fixed to a circuit board 4 in such a manner that above 60% of the exposed area of the surface of the capacitor 1 covered with no external electrodes 2 and confronting the board 4 is occupied by a preliminarily fastening adhesive agent 5. Thereafter, the external electrodes 2 are fixed with solder 6 to a land pattern 3 on the circuit board 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type electronic component mounting body in which a chip type electronic component having external electrodes at both ends of a ceramic element such as a laminated ceramic capacitor is mounted on a circuit board.

[0002]

2. Description of the Related Art A monolithic ceramic capacitor will be described as an example of a chip type electronic component.

Conventionally, as shown in FIG. 1, a monolithic ceramic capacitor 1 is temporarily fixed on a circuit board 4 with an adhesive 5 applied beforehand, and then an external electrode 2 is connected to a land pattern 3 by a solder 6. The monolithic ceramic capacitor 1 was mounted by fixing. Then, the adhesive 5 was set to be 50% or less of the area of the portion of the fixed surface not covered by the external electrode 2.

FIG. 2 shows a measurement state of the bending resistance of the substrate in the mounted state of the monolithic ceramic capacitor 1,
When the center portion of the circuit board 4 whose both ends are supported by the fulcrum 7 is pushed and bent by the push rod 8, the land pattern 3 and the solder 6
If the tensile stress exceeds the strength of the ceramic material, the monolithic ceramic capacitor 1 will be broken through the via.

This board bending resistance is as shown in FIG.
Adhesive 5 occupying a portion (h * w) of the fixed surface of the circuit board of the monolithic ceramic capacitor 1 which is not covered by the external electrode 2.
Affected by the area of.

In such a monolithic ceramic capacitor 1, substrate bending resistance is an important characteristic for guaranteeing reliability after mounting on the circuit board 4, and substrate bending resistance of at least 2 mm is required. There is.

[0007]

In the above structure, the bending resistance of the substrate is relatively weak, and some of them have a bending resistance of about 2.0 to 3.0 mm. Therefore, the stress generated by the break or warpage of the circuit board 4 after mounting is caused. However, there is a problem that cracks are likely to occur at the contact points between the land pattern 3 and the external electrode 2, leading to poor conduction and poor insulation resistance.

Therefore, in the present invention, the portion (h * w) of the chip-type electronic component, which is not covered with the external electrodes, on the circuit board fixing surface is used.
It is an object of the present invention to provide a chip-type electronic component mounting body having an improved bending resistance of the substrate by increasing the area of the adhesive occupying the substrate.

[0009]

To achieve this object, the present invention provides a chip-type electronic component having a substrate, a land pattern provided on the substrate, and external electrodes fixed on the land pattern at both ends. And an adhesive that temporarily fixes the chip-type electronic component and the substrate, and the adhesive contacts 60% or more of the area of the part of the chip-type electronic component that is not covered by the external electrodes on the substrate fixing surface. It was done like this.

[0010]

With this structure, the stress generated when the substrate is bent is not concentrated on the contact points between the land pattern and the external electrodes, and the stress can be relieved on the entire chip, so that the bending resistance of the substrate is improved accordingly. .

[0011]

An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 3, 60 to 90% of the exposed area (h * w) of the fixed surface of the laminated ceramic capacitor 1 to the circuit board 4 which is not covered by the external electrodes 2 is used for temporary fixing. It was fixed to the circuit board 4 so that the adhesive 5 occupied it. Then, the external electrode 2 was fixed to the land pattern 3 on the circuit board 4 with solder 6. Here, as the adhesive,
A one-pack type thermosetting epoxy resin was used.

With this structure, the substrate bending resistance of the monolithic ceramic capacitor is improved. Next, as shown in FIG. 2, substrate bending resistance of this multilayer ceramic capacitor was measured.

As shown in FIG. 3, (Table 1) has a total length H of 2.
The area where the temporary adhesive 5 occupies 30% of the area of the exposed portion not covered with the external electrodes 2 at both ends of the monolithic ceramic capacitor 1 having a width of 0 mm and a width w of 1.25 mm is 30%, 6%.
20 pieces of each of the monolithic ceramic capacitors 1 provided so as to be 0% and 90% were prepared, and the minimum value (hereinafter, min) and the average value (hereinafter, X And) is shown.

[0015]

[Table 1]

Substrate bending resistance is important for X as well, but min is more important than that. As is clear from (Table 1), when the area of the temporary adhesive 5 is changed from 30% to 60%, the bending resistance of the substrate becomes X from 2.3 mm to 4.1 mm, and min is 2.0 mm. Was improved from 3.0 mm to 3.0 mm.

Further, by setting the area of the temporary adhesive 5 to 90%, the bending resistance of the substrate was improved to a min of 5.0 mm or more.

In this embodiment, the laminated ceramic capacitor 1 is exemplified as the chip type electronic component, but the same effect can be obtained if the chip type electronic component is made of ceramic and the external electrodes 2 are provided at both ends.

In this embodiment, a one-pack type thermosetting epoxy resin is used as the adhesive 5. This is because if the adhesive cures at room temperature, it cannot be fixed to the circuit board 4. .

Further, the larger the area of the adhesive 5 in the portion (h * w) of the fixed surface of the chip-type electronic component that is not covered by the external electrodes 2, the greater the effect of alleviating the stress due to bending of the circuit board 4. . Further, it is desirable that the adhesive 5 be applied without protruding from the substrate fixing surface of the chip type electronic component when the mounting apparatus is viewed from above.

[0021]

As described above, according to the present invention, the area occupied by the temporary adhesive is 60% or more of the area of the chip fixing surface of the chip type electronic component which is not covered by the external electrodes. The stress generated by bending does not concentrate on the contact points between the land pattern on the board and the external electrodes, and the stress can be relieved to the entire chip-type electronic component. Therefore, the board bending resistance can be improved accordingly. it can.

[Brief description of drawings]

FIG. 1 is a sectional view of a mounting body of a monolithic ceramic capacitor.

FIG. 2 is a cross-sectional view illustrating measurement of substrate bending resistance of a monolithic ceramic capacitor.

FIG. 3 is a perspective view of a monolithic ceramic capacitor.

[Explanation of symbols]

 1 Multilayer Ceramic Capacitor 2 External Electrode 3 Land Pattern 4 Circuit Board 5 Adhesive

Claims (1)

[Claims] 1. A substrate, a land pattern provided on the substrate, a chip-type electronic component having external electrodes at both ends fixed to the land pattern, and mounting by temporarily fixing the chip-type electronic component and the substrate. And a bonding agent, the adhesive being in contact with 60% or more of the area of the portion of the chip-type electronic component that is not covered with the external electrodes on the substrate fixing surface.