JP2003017302A - Surface mounting type electronic component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface mounting type electronic component in the excellent productivity by realizing higher resistance for heat cycle without use of a jig to keep positional accuracy in the reflow process. SOLUTION: This surface mounting type electronic component has configuration that two metal wires are wound to an insulator plate, an electronic component is held between two metal wires so that a pair of terminal electrodes thereof are in contact with the metal wires, and these terminal electrodes are connected to metal wires with solder.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface mount electronic component.

[0002]

2. Description of the Related Art With the recent computerization of automobiles, severe environmental resistance is required for electronic parts used in such electronic devices. Further, in such circumstances, the surface mounting of electronic components is also progressing, and particularly, the severe temperature cycle property is required for the connection between such surface mounting type electronic components and the substrate. For electronic components and mounting boards,
This is because the coefficient of thermal expansion differs depending on the material, and mechanical stress is applied to the joint between the mounting substrate and the electronic component, which may lead to a decrease in connection strength and an opening.

Here, in the case of a lead wire type electronic component which has been conventionally used, the electronic component is connected to the mounting substrate via a lead wire, and the difference in the thermal expansion coefficient between the electronic component and the mounting substrate is caused. Since the mechanical stress is absorbed by the lead wire portion, the heat cycle resistance of the connection portion was high.

Also in the surface mount type electronic parts, in order to realize high heat cycle resistance, means for relieving mechanical stress is provided between the connecting parts with the mounting board. Specifically, as shown in FIG. 4, the terminal electrode 1 of the electronic component 11 is
There is a means of connecting the metal cap 14 to the solder 2 with the solder 13 and soldering to the mounting substrate (not shown) through the metal cap 14. Therefore, the electronic component 11
The structure is lifted from the mounting substrate, and the metal cap 14 relieves the mechanical stress.

However, in the structure using such a metal cap, although the mechanical stress of the electronic component and the mounting substrate is relieved, it is necessary to consider the mechanical stress at the connecting portion between the metal cap and the electronic component main body. After all, in order to relieve the mechanical stress at the connection between the metal cap and the electronic component body,
For example, it is necessary to use a conductive resin as a mechanical stress relieving material for a terminal electrode of an electronic component, or to use high-temperature solder having a high Pb ratio and a soft alloy itself.

[0006] In addition, for any terminal electrode, when the metal cap and the electronic component body are joined together, usually solder paste is used for reflow. In this case, it is difficult to maintain the positional accuracy of the joining of the metal cap and the electronic component body, and in order to maintain the positional accuracy, it is necessary to fix the electronic component body with the metal cap fitted by a jig.

[0007]

As described above, in the case where the metal cap is used, it is necessary to relieve the mechanical stress between the metal cap and the electronic component main body, and the metal cap and the electronic component main body must be relaxed. When the joining is performed by reflow using a solder paste, it is difficult to maintain the positional accuracy of the joining of the metal cap and the electronic component body, which causes a problem that it takes time.

The present invention has been made to solve the above-mentioned problems, and realizes high heat cycle resistance and does not use a jig for maintaining the positional accuracy during reflow, It is an object of the present invention to provide a surface mount electronic component with good productivity.

[0009]

In order to solve the above-mentioned problems, in the present invention, two metal wires are wound around an insulating plate, and an electronic component is provided between the two metal wires. The pair of terminal electrodes of is sandwiched so as to contact the metal wire,
By configuring the terminal electrode and the metal wire that are in contact with each other with solder, the mechanical stress during heat cycle is relieved by the metal wire, and the component body is sandwiched by the metal wire during reflow. Therefore, there is no displacement even without using a jig.

Further, if a groove or a hole for winding the metal wire is provided on the insulating plate, the metal wire can be easily wound and the metal wire will not easily come off.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The surface mount type electronic component of the present invention is manufactured as follows using a ceramic chip varistor as an example. Two Cu wires pre-plated with Sn are wound around the glass epoxy insulating plate provided with two pairs of guide grooves along the respective guide grooves. A laminated ceramic chip varistor prepared in advance by a known means is sandwiched between the metal wires so that the terminal electrode contacts the Cu wire, and the Sn-plated Cu wire and the terminal electrode of the laminated ceramic chip varistor are reflow-soldered. Attach it to the finished product.

Here, the guide groove provided in the insulating plate may have any shape and size as long as the Cu wire is wound without any trouble. Further, the same effect can be obtained not only by the guide groove but also by the guide hole, and in that case, the shape and the size do not matter.

It is desirable that the Cu wire, which is a metal wire, be plated in advance to improve the solder wettability so that the solderability is improved during reflow.

[0014]

EXAMPLES Specific examples will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, 8.3 × 7.1 ×
Φ0.8mm on 1.2mm glass epoxy insulation board 1
The guide groove 2 is provided, and a wire diameter of 0.6 m
m Sn plated Cu wire 3 was wrapped. This Cu
A 7.5 × 6.3 × 4.0 mm multilayer chip varistor 5 having a pair of terminal electrodes 4 made of 73% Ag and 27% Pd was inserted into the wire 3. Next, the eutectic solder paste is Cu
The wire 3 and the terminal electrode 4 of the multilayer chip varistor 5 were applied, and reflow soldering was performed at a peak temperature of 220 to 230 ° C. for 6 seconds to obtain a finished product.

The surface mounting varistor completed as described above was mounted on a FR-P glass epoxy mounting substrate having a thickness of 1.2 mm, and heat cycle resistance was confirmed. Use eutectic solder paste for soldering to the mounting board.
Reflow soldering was performed at ˜230 ° C. for 6 seconds.

As a conventional example, a laminated chip varistor similar to that of the above-described embodiment is directly mounted on a mounting substrate, and as a reference example, a terminal electrode is provided with a conductive resin for relieving mechanical stress as shown in FIG. The heat cycle resistance of the one used and connected to the mounting substrate with a metal cap is shown.

[0018]

[Table 1]

As shown in Table 1, according to the present invention,
Since the mechanical stress at the time of heat cycle is relaxed by the metal wire, it has the same heat cycle resistance as the one using a metal cap, and it is also necessary to use a relaxation material to relax the mechanical stress at the terminal electrode. In addition, since the component body is sandwiched between the metal wires during reflow, there is no displacement even without using a jig, so that it is possible to provide a surface mount electronic component with good workability and high productivity.

As another embodiment, as shown in FIG. 3, not the guide groove but the guide hole 6 is provided in the insulating plate 1, and the Cu wire 3 is wound around the guide hole 6 to form the laminated chip varistor 5.
The same effect can be obtained by pinching.

[0021]

According to the present invention as described above, it has a high heat cycle resistance and further, it is not necessary to use a jig for maintaining the positional accuracy as in the case of using a metal cap. Thus, it is possible to provide a surface mount electronic component with high productivity.

The present invention is not limited to the above embodiment, and the surface mounting electronic component is not limited to the varistor, but can be applied to other surface mounting electronic components such as ceramic capacitors.

[Brief description of drawings]

FIG. 1 is a plan view showing a surface mount electronic component of the present invention.

FIG. 2 is a side view showing a surface mount electronic component of the present invention.

FIG. 3 is a plan view showing another surface mount type electronic component of the present invention.

FIG. 4 is a side view showing a conventional surface mount electronic component.

[Explanation of symbols]

1 insulating plate 2 guide groove 3 Cu wire 4 terminal electrodes 5 Multilayer chip varistor 6 guide holes

Claims (2)

[Claims] 1. An insulating plate around which two metal wires are wound,
A surface characterized in that an electronic component is sandwiched between metal wires of a book so that a pair of terminal electrodes of the electronic component are in contact with the metal wire, and the terminal electrode and the metal wire in contact with each other are soldered together. Mounted electronic components. 2. The surface mount type electronic component according to claim 1, wherein the insulating plate is provided with a groove or a hole for winding a metal wire.