JP2003154451A - Light beam soldering method and light beam soldering apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus with which an irradiating treatment can be applied for a short time, in a light beam soldering method and a light beam soldering apparatus irradiating a plurality of cream solders (S) coated on a base material (W) to be treated. SOLUTION: In the irradiation of the plurality of cream solders (S) coated on the base material (W) to be treated, the converged light beam irradiating from a light beam irradiating part (1), is introduced into a cylindrical member (3) having a reflecting characteristic in the inner surface. This irradiating treatment is peculiarly applied by setting the above cylindrical member (3) to the opening part and the length, with which the irradiating treatment can be applied at a position widened into such optimum range so as to collectively irradiate the plurality of cream solders (S) on the base material (W) to be treated after converging the irradiating light beam from this light beam irradiating part (1) at least at once.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical soldering method and an optical soldering apparatus, and more particularly to an optical soldering method and apparatus for bonding a chip capacitor to a flexible substrate.

Recently, flexible substrates have been used in mobile phones and small personal computers, and chip capacitors are mounted on the substrates. Electric wiring is pre-formed on the flexible board, and a predetermined amount of cream solder is applied to the area where the chip capacitor should be mounted. The so-called optical solder joining for irradiating with is performed. In this optical solder joint, since the chip capacitor is mounted, it is not always necessary to irradiate only the solder portion. However, by irradiating the substrate or the chip capacitor with light, the solder material is also heated and melted.

FIG. 2 shows a state diagram of a chip capacitor mounted on a flexible substrate. A single flexible substrate W has a plurality of chip capacitors C (C1, C2 ...
・) Is placed, and each capacitor is irradiated with light and soldered. That is, when the optical solder joining of one chip capacitor is completed, the stage of the chip capacitor is moved to perform optical solder joining of the next chip capacitor, and this is repeated in sequence.

Examples of the optical soldering method and apparatus include, for example, Japanese Patent No. 2554182 and Japanese Patent No. 251592.
Japanese Patent No. 2898075, Japanese Patent No. 2745827
Japanese Patent No. 2590613, Japanese Patent No. 2538130
No. 2, Patent No. 2669321, Jikken 7-35648
No. 6-41713, JP-A-6-216516
As disclosed in Japanese Patent Publication No. 2000-242242, a xenon lamp or a laser beam is condensed to irradiate a target area.

However, with the miniaturization of mobile phones and personal computers, the number of capacitors to be coated on one flexible substrate tends to increase. Therefore, there is a problem that it takes time to irradiate each chip capacitor with light for soldering.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an optical soldering method for irradiating a plurality of cream solders coated on a substrate to be processed, and an optical soldering apparatus, in which irradiation treatment is carried out in a short time. Method and apparatus.

[0007]

In order to solve the above-mentioned problems, the optical soldering method of the present invention is a light condensing light radiated from a light irradiating part when a plurality of solders are applied to a substrate to be treated and the solder is radiated. The light is introduced into a cylindrical member having a reflection characteristic on the inner surface, and at least 1
After the light has been focused twice, the cylindrical member is set to have an opening and a length such that the irradiation processing can be performed when the solder spreads over an optimum area that can collectively irradiate a plurality of solders on the substrate to be subjected to the irradiation processing. It is characterized by performing.

Further, the optical soldering apparatus of the present invention is an apparatus for irradiating a plurality of solders applied on a substrate to be processed, and a light irradiating section for emitting condensed light and a plurality of solders to be processed. The stage on which the base material is installed, and the light irradiation unit and the stage, which is arranged between the stage and has a substantially cylindrical reflecting member having an inner surface having a reflection characteristic, the reflecting member emits light from the light emitting unit. After the light is focused at least once, it is characterized by having an opening and a length that can be subjected to irradiation treatment when it spreads to an optimum region for collectively irradiating a plurality of solders on the substrate to be treated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic configuration diagram of an optical soldering device of the present invention. The entire structure of the light soldering device is composed of a light irradiation unit 1, a stage 2, and a reflecting member 3 having a substantially cylindrical shape. The light irradiation unit 1 contains a xenon lamp, a halogen lamp, and a YAG laser as a light source, and the emitted light from this light source is emitted from the light irradiation unit 1 via an optical element such as an elliptical focusing mirror. To be done. The light irradiator 1 can have a light source arranged outside and guide the light with an optical fiber, but by incorporating a light source as in this embodiment, high energy efficiency can be obtained. In addition, more preferably, a mirror-integrated xenon lamp manufactured by Ushio Inc. can be used as the light source. By incorporating this lamp, for example, a maximum of about 30W for a 300W lamp input
It is possible to obtain irradiation energy of (conversion efficiency 10%), and since the lamp is extremely small, the entire light irradiation unit can be made small. The mirror-integrated xenon lamp itself is described in, for example, Japanese Patent No. 3158873.
No., Patent No. 2823800, Patent No. 3183145
And Japanese Patent No. 3183151. Further, a shutter is provided in the light irradiation unit 1, and the emission from the light irradiation unit 1 is controlled by opening and closing the shutter in addition to lighting the lamp.

A flexible substrate W which is an object to be processed is set on the stage 2. This stage 2
For example, it is made of stainless steel, and an X-axis, Y-axis, Z
It can move in the axis and rotation axis directions.

As shown in FIG. 2, the flexible substrate W is made of, for example, a polyimide resin and has a size of 10 mm × 10 mm. Although not shown, a wiring pattern is also formed on the front surface or the back surface of the substrate W. The substrate to be treated means a treated product in a broad sense including a flexible substrate and a conventional plate-shaped printed circuit board.

Electronic components such as chip capacitors are mounted on the flexible substrate W via cream solder S. Note that the electronic component is not limited to a chip capacitor, but in a device for performing collective irradiation as in the present invention, a power supply line is not exposed, and a chip capacitor that can form a power supply mechanism only by mounting is particularly preferable. It is useful.

As the solder S, for example, cream solder is used. Here, "cream solder" refers to a material in which flux and other impurities are mixed in a material such as tin or lead to form a cream, and the oxide film previously formed on the substrates to be soldered is soldered. It has the great advantage that it sometimes peels off and does not generate an oxide film even during the soldering process. In addition, the use of cream solder eliminates the need for the processing atmosphere to be an inert gas atmosphere, which has the advantage of simplifying the structure of the apparatus. As shown in FIG. 2, the claim solder S is applied at a position where it makes an electrical connection with the chip capacitor C. The size of this region is, for example, 3 mm × 1.5 mm. However, in the present invention, the solder S is not limited to the cream solder, and other solder materials such as Au-based solder may be used.

The tubular reflecting member 3 is made of, for example, stainless steel and has a rectangular cross section, and has an opening area of 15 mm × 15 m.
It has a length of m and a length of 180 mm, and its inner surface has light reflection characteristics. This reflecting member 3 is, as shown in FIG.
After the condensed light emitted from the light irradiation unit 1 is condensed once,
The flexible substrate W has such a length and an opening diameter that it can irradiate the substrate satisfactorily at a position where a spread enough to irradiate all the bonding regions is formed. Although the irradiation amount per unit area decreases, by increasing the irradiation time, the cream solder S can be melted at all the bonding points and the chip capacitor C and the flexible substrate W can be bonded.

Since the object to be processed is usually rectangular, the reflecting member 3 has a rectangular cross section.
The shape is not limited to this, and may be circular or elliptical in cross section. Further, as shown in FIG. 3, the size of the cross-sectional area may be variable.
That is, the irradiation area D can be changed by moving one wall 31 of the reflecting member 3 in the direction of the arrow shown. Note that the structure for changing the irradiation area is not limited to the structure shown in the figure, and various other structures can be applied.

Here, as a method of collectively irradiating all the junction regions, for example, it is conceivable to emit parallel light from the light irradiation unit 1. However, in the case of emitting parallel light from the light irradiating section 1, an expensive optical member such as a condenser lens is required, and the irradiation area of the processing object may be different for each processing object. In this case, changing the emission area of the parallel light requires a more complicated mechanism. In this respect, according to the present invention, optimum processing can be performed for each processing target object only by replacing the tubular member having an extremely inexpensive and simple structure.

Now, experimental results showing the effect of the present invention will be described. The experiment is 10 mm × 1 as shown in FIG.
6 chip capacitors C on 0 mm flexible board
Optical solder joints. In the conventional optical solder joining, for each joining area S1, S2, S3 ... S6,
In order to irradiate the light 6 times in total, the irradiation time is changed to 3 seconds (per 1 time) x 6 times 18 seconds,
For example, the time required to move from the irradiation region S1 to S2 is about 1 second × 5 times, which is 5 seconds.
It took about 3 seconds. On the other hand, in the optical solder joining of the present invention, since the tubular reflecting member is used, it is possible to perform the optical solder joining in all the joining areas by batch irradiation for 6 seconds. That is, it means that the processing time can be shortened to about 1/4 as a whole.

As described above, the optical soldering method and apparatus of the present invention uses the cylindrical member having the reflection characteristic on the inner surface thereof, and after the emitted light from the light irradiating section is collected at least once, By forming a positional relationship such that irradiation processing can be performed in a region that spreads to the optimum area where multiple cream solders on the substrate to be processed can be collectively irradiated, the optical soldering process can be performed collectively on one substrate to be processed. This has the advantage that the processing time can be significantly shortened.

[Brief description of drawings]

FIG. 1 shows an optical solder device of the present invention.

FIG. 2 shows a joined state of a flexible substrate and a chip capacitor.

FIG. 3 shows a tubular reflecting member of the present invention.

[Explanation of symbols]

1 Light irradiation part 2 stages 3 Cylindrical reflector W flexible board C chip capacitor S cream solder

Claims (2)

[Claims] 1. A light soldering method for irradiating a plurality of solders coated on a substrate to be treated, wherein condensed light emitted from a light irradiating section is introduced into a cylindrical member having a reflection characteristic on its inner surface. Then, after the emitted light from the light irradiator is collected at least once, the opening and the length are set so that the plurality of solders on the substrate to be processed can be subjected to irradiation processing when spread to an optimum area for collective irradiation. An optical soldering method, characterized in that the cylindrical member is set to perform the irradiation process. 2. A light soldering device which is coated on a substrate to be processed and irradiates a plurality of solders, and a stage on which a light irradiating part for emitting condensed light and a substrate to be processed coated with a plurality of solders are installed. And a reflecting member which is arranged between the light irradiating section and the stage and has a substantially cylindrical inner surface having a reflection characteristic. The reflecting member collects light emitted from the light irradiating section at least once. An optical solder device having an opening and a length capable of performing irradiation processing after being irradiated with light and then spreading to an optimum region for collectively irradiating a plurality of solders on the substrate to be processed.