JPH01205869A - Laser soldering device - Google Patents

Abstract

PURPOSE:To improve a soldering quality and to reduce cost by providing a preheating means heating a part to be joined of a body to be worked in a laser soldering device. CONSTITUTION:A laser beam leading path 2, condensing lens 4 and the nozzle 5 for injection are respectively provided on a laser beam oscillator 1 and the hot blast generator 12 as for a preheating means and a panel heater 15 are arranged as well. A laser beam 3 is projected on the body IC11 to the worked and the part to be joined of a printed board 14 via the lens 4 and nozzle 5. In this case, preheating is given to the body IC11 to be worked and board 14 by the heat conduction of the hot blast 13 of the generator 12 and heater 15. The rapid heating by the laser beam 3 is thus eliminated and the generations of defective solder ball, defective solder wetting, etc., can be prevented. Consequently the soldering quality is improved and the cost is reduced with the reduction in defect amending works.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a laser soldering device that uses laser light as a heat source to solder workpieces.

[Prior Art] Conventionally, a laser soldering method is known in which laser light is used as a heat source for melting solder. The laser soldering device used in this method generally includes a laser generation source, and a laser emission part for irradiating the laser beam generated from the generation source to a part to be joined consisting of solder and a workpiece. Usually, solder is printed or applied on the parts to be joined in advance and then irradiated with laser light to melt the solder and solder the workpieces.

[Problem to be solved by the invention] When soldering with a conventional laser soldering device, the flux and solvent contained in the solder when melting the solder cause rapid boiling due to rapid heating due to laser beam irradiation. , which caused defects such as the formation of solder poles. Furthermore, since the heat conduction of the workpiece is insufficient, problems such as poor wettability of solder including potato solder have occurred.

Therefore, the present invention prevents the occurrence of solder ball defects caused by rapid laser heating of only the parts to be joined, or solder wetting defects caused by insufficient heat conduction from the laser beam to the workpiece. The present invention provides a new laser soldering device.

[Means for Solving the Problems] The present invention includes a laser generating means, and a laser emitting section for irradiating solder and a part to be joined of a workpiece with a laser beam generated from the laser generating means. The object of the present invention is to provide a laser soldering apparatus characterized by comprising: and a preheating means for preheating at least the part to be joined.

[Operation] According to the present invention, a preheating means for preheating the welding portion of the workpiece is provided in the laser soldering device.

Therefore, according to the present invention, when a laser beam is irradiated to a part to be joined and the part to be joined is rapidly heated, solder poles are generated from the part to be joined and heat transfer from the laser beam to the part to be joined is insufficient. It is now possible to prevent the occurrence of poor solder wetting, and it is now possible to perform high-quality soldering.

[Example] (Example 1) Hereinafter, the present invention will be described in detail based on the example apparatus shown in FIG.

In FIG. 1, 1 indicates a laser beam oscillator as a laser generation source, 2 a laser beam guide path for guiding the laser beam generated from the oscillator 1, and 3 an optical path of the laser beam. 4 is a condensing lens for the laser beam, and 5 is a laser beam emitting nozzle which is a laser emitting part, and the laser is J[tl by this nozzle. 6 is air for removing flux and solvent vapor generated during soldering, and 7 is an air pipe for guiding this air 6. 8 is cream solder, which is placed between the IC lead 9, which is the part to be joined of the IC to be processed, and the board land (joint part) 10 of the printed circuit board (workpiece) 14 for mounting the IC. There is. 12 is a hot air generator serving as a preheating means, and the 8 air 13 generated by this hot air generation a12 preheats the leads 9 of the IC. Note that this hot air can also preheat the cream solder 8 and the portions of the printed circuit board 14 other than the board lands IO. Although a hot air generator alone is sufficient as the preheating means, in this example, a panel heater 15 is also provided. When such a panel heater 15 is provided, the effects of the invention are further improved. Note that this panel heater 15 can also preheat the cream solder 8 and printed circuit board 14 described above.

In the apparatus of the embodiment having the above configuration, the laser beam oscillator l
The laser beam 3 emitted from the laser beam passes through the laser beam guide path 2, is condensed by a condensing lens 4, passes through a laser beam injection nozzle 5, and is directed to the cream solder 8 and the workpiece IC.
II and the respective bonded parts of the printed circuit board 14,
That is, IC leads 9, board lands 10. is irradiated. An appropriate amount of solder 8 is placed in advance on the part to be joined. This solder 8 is heated and melted by the laser beam 3,
The hot air generator 12 emits hot air 13, which performs soldering between the workpiece ICII and the part to be joined on the printed circuit board 14, that is, the IC lead 9 and the board land 10, and the heater 15 emits hot air by heat transfer. , workpiece ICI
1 and the printed circuit board 14 can also be preheated.

As an effect of the above-mentioned embodiment, the conventional soldering method in which the parts to be joined of the workpieces are preheated by the hot air generator 12 and/or the panel heater 15, and rapid heating is performed by the Rede light 3 without preheating. We were able to prevent solder pole defects that occurred in

In addition, it can prevent solder defects (solder wetting) and IC
The reliability of the laser beam and the transfer of heat from the laser beam were improved. In this example, since the cream solder 8 is also preheated, harmful solvents contained in the cream solder can also be vaporized and released during soldering.

Further, since early preheating is possible by using both the hot air generation fi 12 and the panel heater 15 in parallel, preheating can be performed in parallel with laser mounting.

Although the panel heater 15 is used in Fig. 1,
Depending on the application, a hot plate, nichrome wire heater, hot air, lamp heating method, etc. may be used.
Similarly, various changes can be made to the hot air generation @12. That is, the main purpose of preheating in the present invention is to prevent the occurrence of poor solder pole and solder wetting, so the thermal energy conditions that satisfy the preheating of the parts to be joined are found, and a preheating method suitable for that condition is adopted. This makes it possible to perform high quality soldering.

[Effect of the Invention J As explained above, by providing a preheating means for preheating the parts to be joined in the laser device, it is now possible to prevent poor wetting of solder including solder poles and potato solder. This makes it possible to obtain high-quality soldering, which makes it possible to reduce the amount of work needed to correct soldering defects, which was previously required, and to lower soldering mounting costs.

[Brief explanation of the drawing]

FIG. 1 is a conceptual perspective view of a laser soldering device according to an embodiment of the present invention. 1... Laser light oscillator, 2... Laser light guide path. 3... Optical path of laser beam, 4... Condensing lens, 5...
・Laser beam emission nozzle, 6...air, 7...air tube. 8... Cream solder, 9... Part to be joined (IC lead), 10... Part to be joined (board land). 11... Workpiece (IC), 12... Preheating means (hot air generator), 43... Hot air, 14... Workpiece (printed circuit board), 15... Panel heater.

Claims (1)

[Claims] comprising a laser generating means and a laser emitting section for irradiating the solder and a part to be joined of the workpiece with a laser beam generated from the laser generating means, and for preheating at least the part to be joined. A laser soldering device characterized by having a preheating means.