JP2003204149A - Method and apparatus for soldering electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a soldering method and a soldering apparatus that inhibit the occurrence of a soldering ball adhering around the soldering section of an electronic component, at the same time, can obtain a soldering section having superb wettability, and further carry out soldering work efficiently. <P>SOLUTION: A lead terminal 6 of an electronic component 5 is installed on a wiring electrode 9 of a printed circuit board 8. A high-temperature shield gas 15 is sprayed to a junction place 10 of the lead terminal 6, and laser beams 4 are applied for soldering. A condensing unit 3 of a laser oscillator 1 is combined with a gas nozzle 1 of the shield gas for arrangement so that the optical axis of the laser beams 4 is positioned in the outlet of the high-temperature shield gas 15. Additionally, the outlet of the high-temperature shield gas 15 is formed in a slender slip shape, and the laser beams are converged to preferably achieve linear beams and at the same time pass through the slit-shaped outlet for irradiating. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soldering method and apparatus for surface mounting an electronic component on a printed circuit board.

[0002]

2. Description of the Related Art As surface mounted electronic components mounted on a printed circuit board, there are flat package ICs (hereinafter referred to as FPICs) such as QFP (Quad Flat Package) type and SOP (Small Outline Package) type.

The connection between the lead terminals of these electronic components and the wiring electrodes on the printed circuit board side is performed by a method such as soldering. Generally, as a soldering method, a reflow furnace capable of mass production is the mainstream. Further, in the case of electronic parts that cannot be processed by the reflow furnace, a method using a soldering iron, a light beam, hot air, laser light, or the like is performed in the subsequent mounting process.

As a method of supplying the solder material to the soldering portion, a method of screen-printing a solder paste on a wiring pattern of a printed circuit board in advance, a method of using a dispenser capable of repeating application of a minute amount, There is a method of automatically supplying a solder wire.

Further, at the time of soldering, flux is used together with the solder material. The mechanism of solder joining is that the flux is first melted at the time of heating, and the oxide film on the joint surface is chemically peeled off. Then, the melted solder wets and spreads on the surface, and the lead terminal of the electronic component and the wiring electrode of the printed circuit board are joined via the solder material.

On the other hand, JP 2001-158985A, JP 2001-156436A and JP 9-214122A.
The publication discloses a method and apparatus for performing soldering by using both irradiation of laser light and spraying of heated inert gas. Further, among the above, Japanese Patent Laid-Open No. 2001-158
No. 985 and Japanese Patent Laid-Open No. 2001-156436, even if an oxide film is formed on the surface of a lead terminal or the like of an electronic component, a flux is generated by irradiating a laser beam and blowing a heated inert gas. It is described that the oxide film can be removed without using it.

Further, in Japanese Unexamined Patent Publication No. 2001-198670, a high temperature hot inert gas is jetted toward a soldering point along the optical axis of the laser beam while the laser beam is jetted in the jet stream of the hot inert gas. There is disclosed a method of projecting a soldering point onto a soldering point to prevent the temperature of the laser beam from lowering with a hot inert gas, and to perform soldering while performing auxiliary heating and a gas shield at the soldering point.

Further, Japanese Unexamined Patent Publication No. 2001-252762 discloses a method of using a mixed gas of a reducing gas and an inert gas in place of the hot inert gas in the method of the above-mentioned Japanese Unexamined Patent Publication No. 2001-198670. ing.

Further, Japanese Patent Laid-Open No. 5-104279 discloses a light emitting portion such as a xenon lamp or a YAG laser oscillator,
A light collecting unit having a light collecting unit for collecting light of the light emitting unit is provided, and the collected light is irradiated to a heated object such as a soldering section located in the vicinity of the light collecting unit, and Disclosed is a light heating device that heats and melts, the light heating device including a shield gas supply means made of an inert gas or a reducing gas that makes the oxygen concentration in the atmosphere around the object to be heated 5% or less. Has been done. Further, there is shown an embodiment in which the laser light focused by the focusing means is irradiated through the gas nozzle of the shield gas. Further, it is described that the soldering portion is preheated by using the gas temperature adjuster and heating the shielding gas.

Furthermore, Japanese Laid-Open Patent Publication No. 61-253170 discloses a laser for irradiating a laser source and a laser beam emitted from the source to a bonded portion composed of a solder and a workpiece. Disclosed is a laser soldering device including at least an irradiating section, and further provided with a gas discharge means for removing a light shield generated from a joined portion by irradiation of the laser beam. Further, by introducing a gas into the laser light irradiation nozzle, and a laser light emission port,
An embodiment in which the gas discharge port is shared is described.
In addition, when heated air is used as a gas for removing the light shielding material, it is effective in improving soldering efficiency and solder quality, and when an inert gas is used, solder due to oxidation of solder during soldering is used. It is described that it is effective in preventing deterioration of the attachment quality.

[0011]

In such a soldering method for electronic parts, bubbles (gas) inside the molten solder expand and burst during melting and evaporation of the flux and during melting of the solder. At that time, the solder becomes fine particles and easily scatters. If the printed circuit board to which the solder balls are attached is used as it is, the solder balls may drop or move due to some vibration, etc., and may get into other connection wiring parts, causing a short circuit, and impairing the reliability of the printed circuit board. Become.

Further, in the case of processing by a conventional reflow furnace, solder balls, flux residues, etc. have been removed in the next cleaning step. However, recently, it has been pointed out that cleaning with chlorofluorocarbon or the like causes environmental problems, and thus the cleaning process has been often omitted. Therefore, it has been desired to develop a soldering technique capable of effectively suppressing the generation of solder balls.

Further, in the soldering of post-mounted parts that cannot be processed by the reflow furnace, for example, local heating is performed by a soldering iron, a light beam, hot air, laser light, etc., but the temperature of the soldered portion rises rapidly. As a result, solder balls may be generated more often.

On the other hand, Japanese Unexamined Patent Publication No. 2001-198670 and the like propose a method of soldering in which irradiation with a laser beam and spraying of a heated inert gas are used in combination, and in particular, Kaihei 5-104279 discloses that the generation of solder balls can be prevented by spraying a heated shield gas made of an inert gas or a reducing gas together. Since it takes some time to heat the soldering part of, in order to solder the lead terminals of a plurality of semiconductors lined up, heating by blowing a shield gas and soldering by irradiating a laser beam, It is necessary to repeat for each lead terminal,
There was a problem that workability was poor.

The present invention has been made in view of the above problems, and it is possible to suppress the generation of solder balls adhering to the periphery of a soldered portion of an electronic component and obtain a soldered portion having good wettability, Moreover, it is an object of the present invention to provide an electronic component soldering method and an apparatus for the same, which enables efficient soldering work.

[0016]

In order to achieve the above object, a method of soldering an electronic component according to the present invention is such that a lead terminal of an electronic component is installed on a wiring electrode of a printed circuit board, and the lead terminal is installed on the installation portion. In the method of soldering an electronic component, which comprises irradiating a laser beam and spraying a heated shield gas made of an inert gas or a reducing gas, the shield gas is blown out into a long and narrow slit shape. At the same time, the optical axis of the laser light is arranged in the outlet of the shield gas.

According to the soldering method of the present invention, when the soldered portion is irradiated with laser light, the soldered portion is covered with a heated shield gas made of an inert gas or a reducing gas to form a non-oxidizing atmosphere. ing. As a result, new oxidation of the surface of the connection portion is suppressed.

Further, since the connection part and its periphery are preheated or residual heat is caused by the combined use of the sprayed heated shield gas, the local rapid heating is reduced as compared with the conventional soldering using only laser light. . As a result, not only the scattering of the solder balls can be suppressed but also the variation in the temperature distribution can be prevented, so that the wettability of the solder is improved.

Further, since the shape of the outlet of the shield gas is elongated slit-like, the heated shield gas is blown so as to cover the entire row of the plurality of lead terminals protruding from the electronic component. This allows
Compared to the conventional method of spraying the spot-heated shield gas only to the connection area of the lead terminal and its periphery, which are the targets of soldering by irradiation with laser light,
A wider area around each lead terminal is preheated or preheated. Therefore, the connection portion of each lead terminal is more stably preheated or residual heat, and the temperature of the preheating or residual heat of each lead terminal is made more uniform.

From the above, according to the soldering method of the present invention,
It is possible to suppress the scattering of the solder balls and improve the wettability of the solder more stably and without variation with respect to the connecting portions of the plurality of lead terminals protruding from the electronic component.

Further, since the gas is generally invisible, it is difficult to confirm the spraying condition of the shield gas to the soldered portion, and it takes time to adjust the position. However, in the present invention,
By arranging the optical axis of the laser beam of the laser processing head inside the outlet of the shield gas, the position where the shield gas is sprayed can be easily grasped and the position can be adjusted easily. Also, to prevent the gas flow from being affected by electronic components,
For example, the gas may be blown from an angle such as vertical.

Furthermore, since the shape of the outlet of the shield gas is made into a long and narrow slit shape, the shield gas is sprayed at a time along a row of a plurality of lead terminals projecting from the electronic component to preheat or residual heat, and to be non-oxidized. Since the atmosphere can be formed, the plurality of lead terminals can be soldered efficiently in a short time by irradiating laser light in that state.

Further, in the soldering method of the present invention, it is preferable that the laser light is focused so as to be a linear beam and is irradiated while passing through the inside of the shield gas blowing port. According to this, a plurality of lead terminals protruding from the electronic component can be simultaneously heated and soldered, so that the workability of soldering can be further improved.

Further, it is preferable that the outlet of the shield gas is rotated and the linear beam of the laser beam is also rotated together with the outlet according to the arrangement direction of the lead terminals. According to this, even when the lead terminals are projected from both the vertical side and the horizontal side of the chip of the electronic component, the shielding gas blowing port and the laser beam can be emitted without changing the installation direction of the electronic component. The soldering work can be performed simply by rotating the linear beam.

Further, it is preferable to irradiate the laser light in pulses. According to this, when the pulse of the laser light is ON, it is heated, when it is OFF, it is cooled,
By repeating the pulse, soldering can be performed,
The temperature rise of the solder can be controlled so that it does not rise suddenly, and the generation of solder balls is suppressed.

Furthermore, the place to be soldered by the shielding gas is 100 to 1 higher than the melting temperature of the solder.
It is preferable to perform the soldering by heating to a temperature lower by 0 ° C. and irradiating the laser light to the portion to be soldered in that state. According to this, the place to be soldered is heated to a relatively high temperature, and by irradiating the laser beam in that state, the solder is quickly melted and soldered without heating more than necessary. Therefore, it is possible to suppress the generation of solder balls due to overheating and improve the soldering efficiency.

On the other hand, the electronic component soldering apparatus according to the present invention is such that the lead terminals of the electronic component are installed on the wiring electrodes of the printed circuit board, and the portions where the lead terminals are installed are heated and soldered. The apparatus comprises a laser light irradiating means for condensing and irradiating a predetermined position with a laser beam, and a shield gas blowing means for blowing a heated shield gas composed of an inert gas or a reducing gas to a predetermined position, and the shield. The blowout port of the gas blowing unit has an elongated slit shape, and the optical axis of the laser beam emitted by the laser beam irradiation unit is arranged in the blowout port of the shield gas blowing unit.

According to the soldering apparatus of the present invention, when the solder connecting portion is irradiated with the laser beam, the connecting portion is covered with the heated shield gas made of the inert gas or the reducing gas to form the non-oxidizing atmosphere. ing. As a result, new oxidation of the surface of the connection portion is suppressed.

Further, the combined use of the heated shielding gas spraying preheats or preheats the connecting portion and its periphery, so that local rapid heating is reduced as compared with conventional soldering using only laser light. . As a result, not only the scattering of the solder balls can be suppressed but also the variation in the temperature distribution can be prevented, so that the wettability of the solder is improved.

Further, by making the shape of the outlet of the shield gas into the elongated slit shape, the heated shield gas is blown so as to cover the entire row of the plurality of lead terminals protruding from the electronic component. This allows
Compared to a conventional device that sprays a spot-heated shield gas only to the connection area of the lead terminal and its periphery, which are the targets of soldering by irradiation with laser light,
A wider area around each lead terminal is preheated or preheated. Therefore, the connection portion of each lead terminal is more stably preheated or residual heat, and the temperature of the preheating or residual heat of each lead terminal is made more uniform.

From the above, in the soldering apparatus of the present invention,
It is possible to suppress the scattering of the solder balls and improve the wettability of the solder more stably and without variation with respect to the connecting portions of the plurality of lead terminals protruding from the electronic component.

According to the soldering apparatus of the present invention,
Since it is possible to match the optical axis of the laser light irradiated by the laser light irradiation means and the blowing direction of the shield gas heated by the shield gas blowing means, it becomes easy to grasp the blowing position of the shield gas,
The position can be adjusted easily, and the gas can be blown from an angle such as vertical so that the gas flow is not affected by the electronic components.

Further, since the shape of the shield gas outlet is made into an elongated slit shape, the shield gas is sprayed at a time along the row of a plurality of lead terminals protruding from the electronic component to preheat or residual heat, and thus non-oxidized. Since the atmosphere can be formed, the plurality of lead terminals can be soldered efficiently in a short time by irradiating laser light in that state.

In the soldering apparatus of the present invention, the laser beam irradiating means has a condensing means for condensing the laser light into a linear beam, and the linear beam formed by this condensing means. It is preferable that the optical axis of is arranged in the outlet of the shield gas blowing means.
According to this, a plurality of lead terminals protruding from the electronic component can be simultaneously heated and soldered, so that the workability of soldering can be further improved.

Further, it is preferable to have a rotating means for rotating together the blow-out port of the shield gas blowing means and the linear beam having an optical axis in the blow-out port. According to this, even when the lead terminals are projected from both the vertical side and the horizontal side of the chip of the electronic component, the shielding gas blowing port and the laser beam can be emitted without changing the installation direction of the electronic component. Just rotate the linear beam,
Can perform soldering work.

[0036]

1 and 2 show an embodiment of a soldering apparatus according to the present invention.

In FIG. 1, a laser oscillator 1 such as a YAG laser is connected to a condensing unit 3 via an optical fiber 2, and these compose laser light irradiation means in the present invention. The laser light 4 output from the laser oscillator 1 is transmitted through the optical fiber 2 and the condensing unit 3
Is collected through.

A gas nozzle 11 is attached to the laser beam emitting surface of the condenser unit 3. In this case, an air gap is provided in the connection boundary portion so that the heat of the heated shield gas is not conducted to the light collecting unit 3 side and becomes hot. Further, a heat insulating material such as “Durostone” (trade name, (Rochering Group) is installed to provide thermal insulation. An end surface of the gas nozzle 11 on the light-collecting unit 3 side is covered with a transparent panel that transmits laser light, and a nozzle tip 16 having a shield gas outlet is attached to the end surface on the opposite side of the gas nozzle 11.

As shown in FIG. 2, the nozzle tip 16 is
Its cross-sectional shape is a flat plate shape, and a slit-shaped blowout port 19 is formed in the center thereof. The optical axis of the laser beam 4 passes through the center of the blowout port 19.

The size of the blow-out port 19 may be appropriately selected depending on the size and shape of the electronic component to be soldered, but normally, the width a (m) of the inner diameter in FIG. 2 (b) is used.
m) and length b (mm), for example, if the size of one side of the FPIC is width α (mm) and the length is β (mm),
It is preferable that a ≧ α + 2 and b ≧ β + 2. For example, SOP (Small Ou) which is the FPIC to be soldered
The size of one side of the lead of (tline Package) is width 3
(Mm) x length 18 (mm), the size of the outlet 19 is set to width 5 (mm) x length 20 (mm) to correspond to the width and length of one side of the SOP. Can be made.

An inlet 13 for introducing a shield gas 14 such as nitrogen gas is formed at one location on the peripheral surface of the gas nozzle 11. An electric heater 12 and a thermocouple for detecting and controlling the heating temperature are arranged inside the gas nozzle 11, and heat the shield gas 14 introduced from the inlet 13 to heat the high-temperature shield gas 15. The high temperature shield gas 15 is ejected from the blowout port 19 of the nozzle tip 16.

Further, the laser beam condensed through the condensing unit 3 has its optical axis output through the outlet 19 of the nozzle tip 16 of the gas nozzle 11.

On the other hand, wiring electrodes 9 are formed on the surface of the printed circuit board 8, and lead terminals 6 of an electronic component 5 such as an FPIC (flat package IC) are brought into contact with corresponding portions of the wiring electrodes 9. Is installed as. A solder layer 7 formed by screen-printing a solder paste is formed in advance on the soldered portion of the wiring electrode 9. The portion where the lead terminal 6, the solder layer 7, and the wiring electrode 9 are in vertical contact with each other forms a joint portion 10 to be soldered.

Next, an embodiment of the soldering method according to the present invention using the above soldering apparatus will be described.

A plurality of lead terminals 6 extending from both sides of the electronic component 5 are positioned so as to abut corresponding portions of the wiring electrodes 9 of the printed board 8, and the electronic component 5 is mounted on the printed board 8. Set it aside. The solder layer 7 is formed on the wiring electrodes 9 to be soldered, and the lead terminals 6 are placed on the wiring electrodes 9 via the solder layers 7. As the solder material for the solder layer 7, a solder material for electronic components such as a commonly used eutectic solder (Pb-Sn) or lead-free solder is used.

In this state, a shield gas 14 such as nitrogen gas is introduced into the gas nozzle 11 through the inlet 13. The shield gas 14 is heated to preferably 50 to 300 ° C., more preferably 150 to 250 ° C. by the electric heater 12 arranged in the gas nozzle 11. Then, the high-temperature shield gas 15 having the above temperature is ejected from the blowout port 19 of the nozzle tip 16 and is blown to the joining portion 10. At this time, the ejection pressure of the high-temperature shield gas 15 is preferably 0.01 to 0.5 MPa, and the flow rate is preferably 0.5 to 10 NL (liter) / min (depending on the size of the work). In this way, after the joint portion 10 is relatively uniformly preheated or preheated, laser irradiation from the laser oscillator 1 is performed.

That is, the laser beam 4 output from the laser oscillator 1 is introduced into the condensing unit 3 through the optical fiber 2, is condensed by the lens arranged in the condensing unit 3, and the inside of the gas nozzle 11 is guided. As a result, the light is emitted from the blow-out port 19 of the nozzle tip 16, and the joint portion 10,
Particularly, the lead terminals 6 are locally irradiated.

As a result, the solder layer 7 melts and spreads around the portion irradiated with the laser beam 4, and the lead terminal 6 and the wiring electrode 9 are soldered. The oxide films on the surfaces of the lead terminals 6 and the wiring electrodes 9 are burned and removed before soldering by spraying the high-temperature shield gas 15, irradiating the laser beam 4 and flux. Further, since the portion irradiated with the laser beam 4 is an area to which the high temperature shield gas 15 is sprayed, the heated portion is always shielded by the shield gas such as nitrogen gas and the oxidation is prevented.

Further, in the present invention, the nozzle tip 1
High-temperature shield gas 15 blown out from blow-off port 19 of 6
However, it is possible to form the elongated gas blowing region 22 and to gas shield one side of the lead terminal of the SOP. In this state, the laser light 4 can be moved to sequentially irradiate the lead terminals for soldering.

Since the gas blowing region 22 also moves as the laser beam 4 moves, the gas blowing region 22 does not always gas shield all of the lead terminals on one side, but in reality, this does not. It is enough. The length of the gas outlet 19 may be made longer so that the gas can be completely shielded against the movement of the laser light 4 at all times.

Further, since the optical axis of the laser beam 4 is arranged in the blowout port 19 of the nozzle tip 16 of the high temperature shield gas 15, the high temperature shield gas 1 is generated by the laser beam 4.
The blowing direction of No. 5 can be visually confirmed, and the position can be easily adjusted. Further, since the blowing direction of the high-temperature shield gas 15 and the optical axis of the laser beam 4 are the same, the gas flow of the high-temperature shield gas 15 can be blown from an angle at which the electronic component 5 is not affected, for example, from the vertical direction. .

The output of the laser beam 4 is not particularly limited, but usually 1 to 40 W (depending on the type and size of the work) is preferable.

Laser oscillation using a YAG laser or the like is normally performed by continuous oscillation (CW), but the laser output can be pulsed as shown in FIG.
As described above, when the laser output is pulsed, melting is performed when the laser light is ON, and cooling is performed when the laser light is OFF. Also,
By setting the pulse repetition frequency (Hz) or the pulse ON time, the melting temperature of the solder can be easily controlled, so that a rapid temperature rise can be suppressed and the generation of solder balls can be suppressed, and the soldering part can be suppressed. The quality of can be improved.

A mechanical shutter is turned on and off as an internal shutter for pulsing the laser output.
Some of them are turned on, some of which are turned on and off with an electric shutter.

FIG. 3 shows still another embodiment of the soldering apparatus of the present invention. This soldering device
A cylindrical lens 25 is used as a condensing unit, and the collimated laser light 24 having a circular cross section is condensed by the condensing unit 23 by the cylindrical lens 25 to be a laser light 26 having a linear cross section. Further, the nozzle tip 28 of the gas nozzle 27 is made into an elongated rectangular gas outlet 29, and the high temperature shield gas 30 is blown out from the gas outlet 29. Then, the linear laser light 26 passes through the center of the gas blowing port 29 and is irradiated into the blowing region 31 of the high-temperature shield gas 30. The above condensing means is not limited to the cylindrical lens, and any condensing means may be used as long as it condenses the laser light into a linear cross section.

When soldering is performed using this soldering apparatus, by irradiating a linear laser beam 26, for example, one side on one side of many lead terminals of the FPIC is set to one.
Can be soldered once in a while. Further, since the laser beam 26 is irradiated into the gas spraying region 31 of the high-temperature shield gas 30, the soldering with high speed, high efficiency, and high quality is performed in the non-oxidizing atmosphere and in the preheated or preheated state. Is possible.

In the present invention, the output (heat energy) of the high-temperature shield gas is made larger than the output (heat energy) of the laser light, and the soldered portion is heated mainly by the high-temperature shield gas and irradiated with the laser light. The soldering can be performed by supplementarily using the heating by.

That is, for example, in FIG. 1, when soldering an electronic component 5 such as an FPIC onto a printed circuit board 8, a high-temperature shield gas 15 is directly blown to the joint portion 10 and the temperature is 100 to 10 ° C. higher than the melting temperature of the solder. It is possible to perform soldering by heating to a low temperature, more preferably 70 to 20 ° C. lower temperature, and in that state, irradiating laser light auxiliary to melt the solder. When such soldering is performed, among the regions uniformly heated by the high-temperature shield gas, the central portion of the joint portion is irradiated with laser light to locally rapidly increase the temperature,
Faster soldering is possible and thermal energy is used efficiently without waste. Further, it is possible to prevent the joint portion 10 from being excessively heated, suppress the generation of solder balls, and improve the wettability of the solder.

Further, the laser oscillator is not limited to the YAG laser, but other lasers can be used as long as thermal energy processing is possible. Also, normal CW / YA
A G laser may be used, but a commercially available normal pulse YAG laser may be used for pulse output. The normal pulse YAG laser has never been used for soldering because of its high peak output, but the laser output (average output, power density, energy density)
It is possible to convert it to a laser for soldering by keeping the value extremely low.

Further, in the above-mentioned embodiment, the optical fiber is used as the transmission means of the laser light, but the transmission means is not limited to this, and means such as air transmission (for example, reflection transmission by a mirror) may be used. You can also

Further, the shield gas may be either an inert gas or a reducing gas. Further, the inert gas used as the shield gas is not limited to the above-mentioned nitrogen gas, but may be a non-oxidizing gas such as helium gas or argon gas. Further, the reducing gas used as the shield gas may be, for example, hydrogen gas, or may be a mixed gas of the above-described inert gas such as nitrogen gas and reducing gas such as hydrogen gas.

Furthermore, the electronic parts to be soldered to the printed circuit board are not limited to FPICs, other ICs,
It can also be applied to chip resistors, electrolytic capacitors and the like.

FIGS. 5A and 5B show still another embodiment of the soldering device of the present invention. As shown in FIG. 3A, this soldering apparatus has the same configuration as the soldering apparatus shown in FIG.
The gas nozzle 27 and the gas nozzle 27 are integrated to form a lens gas nozzle unit 32, and the lens gas nozzle unit 32 is rotatable about a laser optical axis 33 by a drive mechanism (not shown). .

That is, the cylindrical lens 25
It can rotate in any direction around the optical axis 33, and at that time, the gas nozzle 27 also integrally rotates in the same direction. In addition, the circular laser light 24 is
The laser light 26 is condensed by the cylindrical lens 25 and becomes the laser beam 26, and finally is irradiated as the linear beam 34. The linear beam 34 also rotates in the same direction by the rotation of the cylindrical lens 25.

Therefore, as shown in FIG. 10B, even when the lead wires are coming out from each side of the electronic component, for example, the FPIC 35, the lens gas nozzle unit 32 is rotated according to the direction of each side. Thereby, the elongated rectangular gas outlet 29 and the linear beam 34 of the laser light 26 can be aligned with the arrangement direction of the lead wires on each side.

That is, the gas outlet 29 and the linear beam 34 are arranged so as to be along the arrangement direction 37 of the plurality of lead wires 36 protruding from one side of the FPIC 35, and after soldering, the direction perpendicular thereto The gas outlet 29 and the linear beam 34 can be repositioned and soldered along the arrangement direction 39 of the plurality of lead wires 38 protruding from the other side of the FPIC 35. All lead wires can be efficiently soldered without changing the arrangement or the like.

[0067]

EXAMPLE Using the soldering apparatus shown in FIG. 1, the lead terminals 6 of the electronic component 5 made of FPIC placed on the wiring electrodes 9 of the printed circuit board 8 are preliminarily formed on the wiring electrodes 9. Soldered via layer 7. In addition, in this embodiment, the solder material of the solder layer 7 is a Sn-Ag-Cu based lead-free solder among the solder materials for electronic components. The melting temperature of this solder material is about 220 to 221 ° C.

Nitrogen gas was used as the shield gas 14, and this nitrogen gas was heated to 250 ° C. by the electric heater 12, and the pressure was 0.2 M from the outlet of the nozzle tip 16.
Spraying was performed under the conditions of Pa and a flow rate of 1.5 NL / min.

On the other hand, a YAG laser was used as the laser oscillator 1, and laser light having an output of 10 W was applied for 0.3 seconds (per lead terminal).

In soldering, first, the shielding gas 14 is blown to heat the portion to be soldered to a temperature 30 ° C. lower than the melting temperature of the solder layer 7,
In this state, the laser beam was spot-irradiated to the center of the portion to be soldered to melt the solder, and soldering was performed.

As a result, the soldering speed was 0.3 seconds per lead terminal, and there were no solder balls on the soldered printed circuit board 8.

Further, since the blowing direction of the shield gas 14 and the optical axis of the laser light 4 coincide with each other, it was easy to position the heating spot.

[0073]

As described above, according to the present invention,
When soldering electronic components, laser light and high-temperature shield gas are used together, the optical axis of laser light is placed inside the outlet of the gas nozzle for high-temperature shield gas, and the shape of the outlet for shield gas is made an elongated slit. By preheating or residual heat by spraying a shield gas at once along a row of a plurality of lead terminals protruding from the electronic component, it is possible to form a non-oxidizing atmosphere, so by irradiating laser light in that state, A plurality of lead terminals can be efficiently soldered in a short time.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of a soldering device according to the present invention.

2A and 2B show another embodiment of the soldering device according to the present invention, FIG. 2A is a partially enlarged view of the vicinity of a gas nozzle, and FIG.
FIG. 4A is a sectional view taken along the line AA of FIG.

FIG. 3 is a partially enlarged perspective view near a light collecting unit showing still another embodiment of a soldering device according to the present invention.

FIG. 4 is a table showing an example of pulse output of laser light according to the present invention.

5A and 5B show still another embodiment of a soldering device according to the present invention, FIG. 5A is a partially enlarged perspective view of the vicinity of a light collecting unit, and FIG. 5B is a perspective view of an electronic component.

[Explanation of symbols]

1: Laser oscillator 2: Optical fiber 3, 23: Condensing unit 4, 24, 26: Laser light 5: Electronic components 6: Lead terminal 7: Solder layer 8: Printed circuit board 9: Wiring electrode 10: Joint part 11, 27: Gas nozzle 12: Electric heater 13: Inlet 14: Shield gas 15: High temperature shield gas 16, 28: Nozzle tip 19, 29: Gas outlet 25: Cylindrical lens 32: Lens / gas nozzle unit 33: Optical axis 34: Linear beam 35: FPIC 36, 38: Lead wire

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keiichi Matsumura             1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa             Within Fuji Electric Co., Ltd. (72) Inventor Hiroaki Sozono             1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa             Within Fuji Electric Co., Ltd. (72) Inventor Masahiro Ishikawa             1-1 Tanabe Nitta, Kawasaki-ku, Kawasaki-shi, Kanagawa             Within Fuji Electric Co., Ltd. (72) Inventor Kensei Matsubara             1-2 Tsuchiyama East Town, Himeji City, Hyogo Prefecture             Taisei Kaken F-term (reference) 5E319 AA01 AB01 CC46 GG03

Claims (8)

[Claims] 1. A lead terminal of an electronic component is installed on a wiring electrode of a printed circuit board, a laser beam is irradiated to the installed part of the lead terminal, and a heated shield gas made of an inert gas or a reducing gas is supplied. In a method of soldering an electronic component for soldering by spraying, the shape of the outlet of the shield gas is made into an elongated slit shape, and the optical axis of the laser beam is arranged in the outlet of the shield gas. Soldering method for electronic components. 2. The method of soldering an electronic component according to claim 1, wherein the laser light is focused so as to be a linear beam, and the laser light is radiated by being passed through the inside of the outlet of the shield gas. 3. According to the arrangement direction of the lead terminals,
The method of soldering an electronic component according to claim 2, wherein the blowout port of the shield gas is rotated, and the linear beam of the laser light is also rotated together with the blowout port. 4. The method of soldering an electronic component according to claim 1, wherein the laser light is pulsed and irradiated. 5. A portion to be soldered by the shielding gas is heated to a temperature lower by 100 to 10 ° C. than a melting temperature of the solder, and the laser beam is irradiated to the portion to be soldered in that state to solder. Claim 1 which attaches
4. The method for soldering an electronic component according to any one of 4 above. 6. A soldering apparatus for electronic components, wherein a lead terminal of an electronic component is installed on a wiring electrode of a printed circuit board, and a portion where the lead terminal is installed is heated and soldered.
Laser light irradiation means for converging laser light to irradiate a predetermined location, and shield gas spraying means for spraying a heated shield gas composed of an inert gas or a reducing gas to a predetermined location, the shield gas spraying means Is formed in an elongated slit shape, and the optical axis of the laser beam emitted by the laser beam irradiating means is arranged in the outlet of the shield gas spraying means. 7. The laser light irradiating means has a condensing means for condensing the laser light into a linear beam, and the optical axis of the linear beam formed by the condensing means is the shield gas. 7. The soldering device for electronic parts according to claim 6, wherein the device is arranged in the outlet of the spraying means. 8. The soldering apparatus for an electronic component according to claim 7, further comprising a rotating means for rotating together the blow-out port of the shield gas blowing means and the linear beam having an optical axis in the blow-out port.