JPH05208258A - Soldering device - Google Patents

Abstract

PURPOSE:To provide the soldering device which can solder an electrode having an extremely small width without relying on a large-scale method, such as CVD. CONSTITUTION:The laser beam from an Nd:YAG laser 1 is converted to a doughnut-shaped ring mode by an axicon prism 2 and is converged by a lens 3 so as to focus at the open defect point 5 on a substrate 4. The powder 7 of the solder from a solder powder tank 8 is supplied through a nozzle 9 into a laser beam tunnel. The supplied powder 7 of the solder is passed through the inside of the laser beam tunnel until the powder. arrives at the focus, where the powder is melted. The melt is packed into the open defect point 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering apparatus for repairing a printed circuit board by using a laser beam and generally for soldering on the circuit board.

[0002]

2. Description of the Related Art A printed circuit board may have defects during its manufacturing process. One is a short defect in which electrodes that must be separated are connected to each other, and the other is an open defect in which electrodes that must be connected are disconnected. Short defects could be scraped off with a knife or separated by trimming with a Q-switch pulse laser. The open defect can be welded by Joule heat by bridging the cobalt alloy wire with the broken electrode and applying electricity.

[0003]

However, in the above-mentioned conventional method, it is difficult to repair the defect generated in the portion where the electrode is bent at a right angle. Further, when the IC is highly integrated and high density is required for mounting on a printed circuit board, and a defect occurs in an electrode having a line width of 100 μm or less, it is difficult to repair the defect with a conventional device.

There is also a method of laminating a metal film by CVD for an open defect, but this method has a problem that large-scale equipment is required.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a soldering apparatus capable of soldering electrodes having a narrow line width without using a large-scale method such as CVD. And

[0006]

In order to achieve the above object, the soldering apparatus of the present invention guides solder powder through a light tunnel formed by squeezing a ring-shaped laser beam to form a solder powder on a substrate. It is characterized in that it is melted by laser light and soldered.

[0007]

[Function] The spatial mode of the laser beam with good beam quality has a Gaussian distribution in its intensity distribution. Such a laser beam can be made into a donut-shaped annular mode by passing through a conical axicon prism, and a light tunnel can be created. If such a ring-shaped laser beam is squeezed downward using a lens and solder powder is introduced into the tunnel, the powder is guided in the focal direction by the pressure of the light. That is, the momentum possessed by light acts on the powder and acts as pressure on the powder according to the law of conservation of momentum. Therefore, for example, if the focal point is located at the open defect portion, the solder powder is melted by the focused laser beam to fill the defect portion, and the broken electrodes can be connected.

[0008]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a schematic diagram of a soldering device that guides a solder powder through a light tunnel of a laser beam focused in an annular shape and melts it with a laser on a substrate for soldering. As shown in FIG. 1, the laser light from the Nd: YAG laser 1 is converted into a donut-shaped annular mode by the axicon prism 2 and is squeezed by a lens 3 to open a defective portion 5 on the substrate 4.
Focus on. Solder powder 7 is supplied from a solder powder tank 8 through a nozzle 9 into the laser light tunnel. ON / OFF of the supply of the solder powder is performed by vibrating the nozzle at high speed by the piezoelectric element 10.

The solder powder receives pressure of light, passes through the tunnel, reaches the focal point, is melted by high-density laser light energy near the focal point, and is filled in the open defect portion 5. Further, the specification of the position of the open defect portion and the confirmation of the repair of the open defect portion can be observed through the objective lens 11 of the microscope. In FIG. 1, reference numeral 12 is a reflecting mirror that reflects the laser.

According to the above-mentioned embodiment, since the solder is guided and melted by using the ring-shaped laser, the defect which occurred in the electrode of 100 μm or less, which was conventionally difficult to repair, can be easily repaired. be able to. Further, it is possible to easily repair a defect generated in a portion where the electrode is bent at a right angle.

[0011]

As described above, according to the present invention, by supplying and melting solder using a ring-shaped laser, it is difficult to obtain a high density printed circuit board by the method of welding cobalt alloy wires. To provide a soldering device capable of repairing the open defect part of the same, repairing it at the same time as the inspection of the printed circuit board, and further suppressing the cost which is large and expensive by the CVD method to a simple and low cost. be able to.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a soldering device that is an embodiment of the present invention.

[Explanation of symbols]

 1 Nd: YAG Laser 2 Axicon Prism 3 Lens 4 Substrate 5 Open Defect 6 Electrode 7 Solder Powder 8 Solder Powder Tank 9 Nozzle 10 Piezoelectric Element 11 Objective Lens 12 Reflector

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Claims (1)

[Claims] 1. A soldering device, characterized in that a solder powder is guided through a light tunnel formed by squeezing a ring-shaped laser beam, and is melted by laser light on a substrate for soldering.