JP4024068B2 - Method and apparatus for soldering electronic components - Google Patents

Description

[0001]
BACKGROUND 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]
[Prior art]
As surface mount electronic components mounted on a printed circuit board or the like, there are flat package ICs (hereinafter referred to as FPICs) such as a QFP (Quad Flat Package) type and an SOP (Small Outline Package) type.
[0003]
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. Usually, as a soldering method, processing by a reflow furnace capable of mass production dominates. In the case of an electronic component that cannot be processed by a reflow furnace, a method using a soldering iron, a light beam, hot air, laser light, or the like is performed in a post-installation process.
[0004]
In addition, as a method of supplying solder material to the soldering part, a method of screen printing a solder paste on a wiring pattern of a printed circuit board in advance, a method using a dispenser capable of repeating a minute amount of application, a solder wire There is an automatic supply method.
[0005]
Furthermore, flux is used together with the solder material at the time of soldering. The soldering mechanism is such that the flux first dissolves during heating, and the oxide film on the surface of the joint is chemically peeled off. Then, the melted solder spreads on the surface, and the lead terminals of the electronic component and the wiring electrodes of the printed circuit board are joined via the solder material.
[0006]
On the other hand, Japanese Patent Application Laid-Open Nos. 2001-158985, 2001-156436, and 9-214122 disclose a method of performing soldering using laser light irradiation and heated inert gas spraying in combination. An apparatus is disclosed. Of the above, Japanese Patent Application Laid-Open Nos. 2001-158985 and 2001-156436 irradiate a laser beam and heat it even when an oxide film is formed on the surface of a lead terminal of an electronic component. It is described that the oxide film can be removed by spraying active gas without using flux.
[0007]
Further, Japanese Patent Laid-Open No. 2001-198670 discloses soldering a laser beam in a jet of hot inert gas while jetting hot hot inert gas toward the soldering point along the optical axis of the laser beam. A method is disclosed in which soldering is performed while preventing temperature drop of the laser beam with hot inert gas and performing auxiliary heating and gas shielding of the soldering point by projecting onto the point.
[0008]
Japanese Patent Laid-Open No. 2001-252762 discloses a method 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 Patent Laid-Open No. 2001-198670.
[0009]
Further, Japanese Patent Laid-Open No. 5-104279 is provided with a condensing unit having a light emitting part such as a xenon lamp or a YAG laser oscillator and a light condensing part of the light emitting part, and is located in the vicinity of the light condensing part. A light heating device that irradiates a heated object such as a soldering portion with condensed light to heat and melt the heated object, and an oxygen concentration in an atmosphere around the heated object is 5% or less An optical heating device having a shield gas supply means made of an inert gas or a reducing gas is disclosed. Further, an embodiment in which the laser beam condensed by the condensing means is irradiated through the gas nozzle of the shielding gas is shown. Further, it is described that a soldering portion is preheated by using a gas temperature regulator and heating and using a shielding gas.
[0010]
Furthermore, Japanese Patent Application Laid-Open No. 61-253170 discloses a laser generation source, and a laser irradiation unit for irradiating a bonded portion composed of solder and a workpiece with a laser beam generated from the generation source. There is disclosed a laser soldering apparatus characterized by further comprising a gas discharge means for removing a light shielding material generated from a bonded portion by irradiation of the laser light. In addition, an embodiment is described in which a gas is introduced into a laser light irradiation nozzle and a laser light emission port and a gas discharge port are shared. When heated air is used as a gas for removing the light shielding material, it is effective for improving soldering efficiency and solder quality. When an inert gas is used, solder is oxidized due to oxidation of the solder during soldering. It is described that it is effective for preventing deterioration of the attachment quality.
[0011]
[Problems to be solved by the invention]
In such a method of soldering electronic components, when the flux is melted and evaporated, and when the solder is melted, bubbles (gas) inside the melted solder expand and burst. It is easy to scatter. If the printed circuit board with the solder balls attached is used as it is, the solder balls may drop or move due to some vibration, etc., enter other connection wiring parts, cause a short circuit, etc., and impair the reliability of the printed circuit board. Become.
[0012]
Moreover, in the case of the process by the conventional reflow furnace, a solder ball, a flux residue, etc. have been removed by the following washing | cleaning process. However, recently, it has been pointed out that cleaning with chlorofluorocarbon or the like causes environmental problems, and the cleaning process is often omitted. For this reason, development of the soldering technique which can suppress generation | occurrence | production of a solder ball effectively was desired.
[0013]
Furthermore, in the soldering of post-installation parts that cannot be processed by a reflow furnace, for example, local heating is performed with a soldering iron, light beam, hot air, laser light, etc., but due to the rapid rise in temperature of the soldering part. In some cases, more solder balls are generated.
[0014]
On the other hand, Japanese Patent Application Laid-Open No. 2001-198670 proposes a soldering method using both laser light irradiation and spraying of a heated inert gas or the like. No. 104279 shows that solder ball generation can be prevented by using a spray of heated shield gas made of an inert gas or a reducing gas in combination. Since it takes a certain amount of time to heat the part, in order to solder a plurality of semiconductor lead terminals, heating by spraying a shielding gas and soldering by irradiating a laser beam are performed by the lead terminal 1. There was a problem that workability was poor because it was necessary to repeat it for each book.
[0015]
The present invention has been made in view of the above problems, and can suppress the generation of solder balls adhering to the periphery of a soldered portion of an electronic component, and can obtain a soldered portion with good wettability. An object of the present invention is to provide an electronic component soldering method and apparatus capable of performing work efficiently.
[0016]
[Means for Solving the Problems]
  In order to achieve the above object, the electronic component soldering method of the present invention is such that a lead terminal of an electronic component is placed on a wiring electrode of a printed circuit board, the laser beam is irradiated to the placement portion of the lead terminal, and inactive In a soldering method of an electronic component for performing soldering by spraying a heated shield gas made of a gas or a reducing gas, the shield gas outlet is formed into an elongated slit and the laser beam is a linear beam. Condensing means for condensing the light is provided, the optical axis thereof is disposed in the blowout port of the shield gas, and the shield gas is sprayed to a portion to be soldered, so that the melting temperature of the solder is 100 to 10 While heating to a temperature lower by ℃ and condensing the laser beam into a linear beam in that state, the inside of the shield gas outlet The portion to be the soldering by umbrellaPulsedIrradiated,The shield gas outlet is rotated in accordance with the arrangement direction of the lead terminals, and the linear beam of the laser light is also rotated together with the outlet.It is characterized by that.
[0017]
According to the soldering method of the present invention, when irradiating a solder connection portion with laser light, the connection portion is covered with a heated shield gas made of an inert gas or a reducing gas to form a non-oxidizing atmosphere. Thereby, the new oxidation of the connection part surface is suppressed.
[0018]
Further, since the connection portion and its periphery are preheated or preheated by the combined use of the heated shield gas, local rapid heating is alleviated as compared with the conventional soldering using only laser light. This not only suppresses the scattering of solder balls, but also prevents variations in temperature distribution, thereby improving the wettability of the solder.
[0019]
In addition, since the shape of the shield gas outlet is formed into a long and narrow slit, the heated shield gas is sprayed so as to cover the entire row of the lead terminals protruding from the electronic component. As a result, compared to the conventional method of spraying a shield gas heated in a spot manner only to and around the connection portion of the lead terminal that is the target of soldering by laser light irradiation, the area around each lead terminal is reduced. A larger area is preheated or preheated. Accordingly, the connecting portion of each lead terminal is preheated or preheated more stably, and the preheat or preheat temperature for each lead terminal is made more uniform.
[0020]
As described above, in 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 to the connection portions of the plurality of lead terminals protruding from the electronic component more stably and without variation. It can be carried out.
[0021]
In general, since the gas is not visible, it is difficult to confirm the spraying condition of the shield gas to the soldered part, and it takes time to adjust the position.In the present invention, the optical axis of the laser beam of the laser processing head is set to the shield gas. By arranging in the blowout port, it becomes easy to grasp the spraying position of the shield gas, and the position adjustment becomes easy. Further, the gas can be blown from an angle such as vertical so that the gas flow is not affected by the electronic component.
[0022]
Further, the shape of the shield gas outlet is made into a long and narrow slit, so that a shield gas is sprayed at once along the row of lead terminals protruding from the electronic component to preheat or preheat to form a non-oxidizing atmosphere. Therefore, a plurality of lead terminals can be efficiently soldered in a short time by irradiating laser light in that state.
[0023]
  Also,Irradiating the laser beam through the shielding gas outlet while condensing the laser beam into a linear beam.soSince a plurality of lead terminals protruding from the electronic component can be simultaneously heated and soldered, soldering workability can be further improved.
  Further, the portion to be soldered with the shielding gas is heated to a temperature lower by 100 to 10 ° C. than the melting temperature of the solder, and in that state, the laser beam is irradiated to the portion to be soldered for soldering. By heating the part to be soldered to a relatively high temperature and irradiating the laser beam in that state, the solder can be quickly melted and soldered without heating more than necessary. It is possible to suppress the generation of solder balls due to overheating and to increase the soldering efficiency.
[0024]
  AlsoThe shield gas blowing port is rotated in accordance with the arrangement direction of the lead terminals, and the linear beam of the laser light is also rotated together with the blowing port.soEven if the lead terminal is coming out from both the vertical and horizontal sides of the chip of the electronic component, the shield gas outlet and the linear beam of laser light can be used without changing the installation direction of the electronic component. The soldering operation can be performed simply by rotating.
[0025]
  Further, the laser beam is irradiated in a pulsed manner.soThe soldering can be controlled by repeating the pulses, such as heating when the laser light pulse is ON, and cooling when the laser pulse is OFF. Is suppressed.
[0027]
  On the other hand, the electronic component soldering apparatus of the present invention is an electronic component soldering apparatus in which a lead terminal of an electronic component is installed on a wiring electrode of a printed circuit board and the installation portion of the lead terminal is heated and soldered. Laser beam irradiating means for condensing laser light and irradiating a predetermined location; and shield gas spraying means for spraying a heated shield gas made of an inert gas or a reducing gas to the predetermined location, the shield gas spraying means OutletIsThe laser beam 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. Placed in the outlet of the gas blowing meansA rotating device for rotating together the blowout port of the shield gas blowing means and the linear beam having an optical axis in the blowout port,The shield gas is sprayed on the part to be soldered and heated to a temperature lower by 100 to 10 ° C. than the melting temperature of the solder, and the laser beam is applied to the part to be soldered in that state.PulsedIt is comprised so that it may irradiate.
[0028]
According to the soldering apparatus of the present invention, when irradiating the solder connection portion with the laser beam, the connection portion is covered with a heated shield gas made of an inert gas or a reducing gas to form a non-oxidizing atmosphere. Thereby, the new oxidation of the connection part surface is suppressed.
[0029]
Further, since the connection portion and its periphery are preheated or preheated by the combined use of the heated shield gas, local rapid heating is alleviated as compared with the conventional soldering using only laser light. This not only suppresses the scattering of solder balls, but also prevents variations in temperature distribution, thereby improving the wettability of the solder.
[0030]
In addition, since the shape of the shield gas outlet is formed into a long and narrow slit, the heated shield gas is sprayed so as to cover the entire row of the lead terminals protruding from the electronic component. As a result, compared to conventional devices that spray spot-heated shield gas only on and around the lead terminal connection, which is the target of soldering by laser light irradiation, the periphery of each lead terminal A larger area is preheated or preheated. Accordingly, the connecting portion of each lead terminal is preheated or preheated more stably, and the preheat or preheat temperature for each lead terminal is made more uniform.
[0031]
As described 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 to the connecting portions of the plurality of lead terminals protruding from the electronic component more stably and without variation. It can be carried out.
[0032]
Further, according to the soldering apparatus of the present invention, the optical axis of the laser beam irradiated by the laser beam irradiation unit and the spraying direction of the heated shield gas by the shield gas spraying unit can be matched, so that the shield For example, the gas can be blown from an angle such as vertical so that the gas blowing position can be easily grasped, the position can be easily adjusted, and the gas flow is not affected by the electronic components.
[0033]
In addition, since the shape of the shield gas outlet is formed into a long and narrow slit, a shield gas is sprayed at once along the row of lead terminals protruding from the electronic component to preheat or preheat to form a non-oxidizing atmosphere. Therefore, a plurality of lead terminals can be efficiently soldered in a short time by irradiating laser light in that state.
[0034]
  Further, the laser beam irradiation unit has a condensing unit that condenses the laser beam so as to be a linear beam, and the optical axis of the linear beam formed by the condensing unit is that of the shield gas blowing unit. Placed in the outletHas beenThus, a plurality of lead terminals protruding from the electronic component can be simultaneously heated and soldered, and the soldering workability can be improved.
[0035]
  And a rotating means for rotating together the blowout port of the shield gas blowing unit and the linear beam having an optical axis in the blowout port.soEven if the lead terminal is coming out from both the vertical and horizontal sides of the chip of the electronic component, the shield gas outlet and the linear beam of laser light can be used without changing the installation direction of the electronic component. The soldering operation can be performed simply by rotating.
[0036]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an embodiment of the soldering apparatus of the present invention.
[0037]
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 constitute a laser beam irradiation means in the present invention. The laser beam 4 output from the laser oscillator 1 is transmitted through the optical fiber 2 and condensed through the condensing unit 3.
[0038]
A gas nozzle 11 is attached to the laser light emitting surface of the light collecting unit 3. In this case, an air gap is provided at the connection boundary portion so that the heat of the heated shield gas is not heated due to conduction to the light collecting unit 3 side, and a heat insulating material such as “Duro Stone” (trade name, Roscheling Group) is installed to insulate the heat. An end face 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 chip 16 having a shield gas outlet is attached to the opposite end face of the gas nozzle 11.
[0039]
As shown in FIG. 2, the nozzle chip 16 has a flat plate shape in cross section, and a slit-shaped outlet 19 is formed at the center thereof. The optical axis of the laser beam 4 passes through the center of the blowout port 19.
[0040]
The size of the blowout port 19 may be appropriately selected depending on the size and shape of the electronic component to be soldered. Usually, the width a (mm) and the length b (mm) of the inner diameter in FIG. ) Is preferably a ≧ α + 2 and b ≧ β + 2 where the size of one side of the FPIC is a width α (mm) and the length is β (mm), for example. For example, when the size of one side of a lead of an SOP (Small Outline Package), which is an FPIC to be soldered, is 3 (mm) wide by 18 (mm) long, the size of the outlet 19 is 5 ( mm) × length 20 (mm), it is possible to correspond to the width and length of one side of the SOP.
[0041]
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. Further, an electric heater 12 and a thermocouple for detecting and controlling the heating temperature are arranged inside the gas nozzle 11, and the shield gas 14 introduced from the introduction port 13 is heated to heat the high-temperature shield gas 15. The high temperature shield gas 15 is ejected from the outlet 19 of the nozzle chip 16.
[0042]
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.
[0043]
On the other hand, wiring electrodes 9 are formed on the surface of the printed circuit board 8, and for example, the lead terminals 6 of the electronic component 5 such as an FPIC (flat package IC) are installed so as to contact the corresponding portions of the wiring electrodes 9. Has been. A solder layer 7 formed by screen printing a solder paste is formed in advance on a soldered portion of the wiring electrode 9. And the part where the lead terminal 6, the solder layer 7, and the wiring electrode 9 contact | abutted up and down has comprised the joining location 10 which should be soldered.
[0044]
Next, an embodiment of a soldering method according to the present invention using the above soldering apparatus will be described.
[0045]
A plurality of lead terminals 6 extending from both sides of the electronic component 5 are positioned so as to come into contact with corresponding portions of the wiring electrodes 9 of the printed circuit board 8, and the electronic component 5 is placed on the printed circuit board 8. deep. The solder layer 7 is formed on the wiring electrode 9 to be soldered, and the lead terminal 6 is placed on the wiring electrode 9 through the solder layer 7. Moreover, as a solder material of the solder layer 7, a solder material for electronic parts such as a commonly used eutectic solder (Pb-Sn) or lead-free solder is used.
[0046]
In this state, a shield gas 14 such as nitrogen gas is introduced into the gas nozzle 11 from the introduction port 13. The shield gas 14 is preferably heated to 50 to 300 ° C., more preferably 150 to 250 ° C., by the electric heater 12 disposed 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 chip 16 and is sprayed onto the joint portion 10. At this time, the jet 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) / minute (depending on the size of the workpiece). In this way, after preheating or preheating the joint portion 10 relatively uniformly, laser irradiation from the laser oscillator 1 is performed.
[0047]
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 collected by a lens disposed in the condensing unit 3, passes through the gas nozzle 11, and passes through the nozzle. The light is emitted from the blowout port 19 of the chip 16 and is locally irradiated to the joint portion 10, particularly the lead terminal 6.
[0048]
As a result, the solder layer 7 is melted 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 out 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 a region where the high temperature shield gas 15 is sprayed, the heated portion is always shielded with a shield gas such as nitrogen gas, and oxidation or the like is prevented.
[0049]
Further, in the present invention, the high-temperature shield gas 15 blown out from the outlet 19 of the nozzle chip 16 forms an elongated gas blowing region 22 and can gas shield one side of the SOP lead terminal. Soldering can be performed by sequentially irradiating the lead terminals while moving the laser beam 4 in this state.
[0050]
In addition, since the gas spraying region 22 also moves as the laser beam 4 is moved, the gas spraying region 22 does not always gas shield all of the lead terminals on one side, but this is sufficient in practice. . Note that the length of the gas outlet 19 may be made longer so that the gas can always be completely shielded against the movement of the laser beam 4.
[0051]
Furthermore, since the optical axis of the laser beam 4 is disposed in the blowout port 19 of the nozzle tip 16 of the high temperature shield gas 15, the spray direction of the high temperature shield gas 15 can be visually confirmed by the laser beam 4. Easy to adjust. In addition, since the spray 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 sprayed from an angle that is not affected by the electronic component 5, for example, the vertical direction. .
[0052]
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 workpiece) is preferable.
[0053]
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. In this way, when the laser output is pulsed, the laser beam is melted when it is ON, and cooled when it is OFF. In addition, the setting of the pulse repetition frequency (Hz) or the pulse ON time makes it easy to control the melting temperature of the solder, so that a rapid temperature rise can be suppressed and the generation of solder balls can be suppressed. The quality of the attachment part can be improved.
[0054]
The internal shutter for pulsing the laser output includes a mechanical shutter that is turned on and off, and an electrical shutter that is turned on and off.
[0055]
FIG. 3 shows still another embodiment of the soldering apparatus of the present invention.
This soldering apparatus uses a cylindrical lens 25 as a condensing means, and condenses the laser light 24 having a circular cross-section collimated by the condensing unit 23 by the cylindrical lens 25 in the condensing unit 23 and has a linear cross section. I have to. In addition, the nozzle tip 28 of the gas nozzle 27 is an elongated rectangular gas outlet 29, and the high temperature shield gas 30 is blown out from the gas outlet 29. The linear laser beam 26 is irradiated into the blowing region 31 of the high-temperature shield gas 30 through the center of the gas blowing port 29. The condensing means is not limited to the cylindrical lens, and any condensing means may be used as long as it condenses so that the cross section of the laser light is linear.
[0056]
When soldering using this soldering apparatus, for example, one side of many lead terminals of the FPIC can be soldered at a time by irradiating the linear laser beam 26. Further, since the laser beam 26 is irradiated into the gas spray region 31 of the high temperature shield gas 30, high-quality, high-quality soldering is performed in a non-oxidizing atmosphere and in a preheated or preheated state. Is possible.
[0057]
In the present invention, the output (thermal energy) of the high temperature shield gas is made larger than the output (thermal energy) of the laser beam, the soldered part is mainly heated by the high temperature shield gas, and the heating by the laser beam irradiation is performed. Auxiliary use can be used for soldering.
[0058]
That is, for example, in FIG. 1, when soldering the electronic component 5 such as FPIC onto the printed circuit board 8, the high temperature shield gas 15 is directly sprayed on the joint 10, and the temperature is 100 to 10 ° C. lower than the melting temperature of the solder More preferably, it is heated to a temperature lower by 70 to 20 ° C., and in this state, laser light is supplementarily irradiated to melt the solder and soldering can be performed. When such soldering is performed, in the region heated uniformly by the high-temperature shield gas, the central portion of the joint is irradiated with laser light, and the temperature rapidly rises locally. This makes it possible to use heat energy efficiently without waste. Moreover, it can prevent that the joining location 10 is heated too much, can suppress generation | occurrence | production of a solder ball, and can also improve the wettability of a solder.
[0059]
The laser oscillator is not limited to a YAG laser, and other lasers can be used as long as thermal energy processing is possible. In addition, a normal CW • YAG laser may be used, but a commercially available normal pulse YAG laser can also be used when outputting a pulse. The normal pulse YAG laser has never been used for soldering because of its high peak output, but by suppressing the laser output (average output, power density, energy density) extremely low, Diversion is possible.
[0060]
Further, in the embodiment, the optical fiber is used as the laser beam transmission means, but the transmission means is not limited to this, and for example, means such as air transmission (for example, transmission of reflection by a mirror) can be used.
[0061]
Furthermore, the shielding gas may be either an inert gas or a reducing gas. Further, the inert gas used as the shielding gas is not limited to the nitrogen gas described above, but may be helium gas or argon gas which are non-oxidizing gases. The reducing gas used as the shielding gas may be hydrogen gas, for example, or may be a mixed gas of an inert gas such as nitrogen gas as described above and a reducing gas such as hydrogen gas.
[0062]
Furthermore, the electronic component to be soldered to the printed circuit board is not limited to the FPIC, but can be applied to other ICs, chip resistors, electrolytic capacitors, and the like.
[0063]
5 (a) and 5 (b) show still another embodiment of the soldering apparatus of the present invention. As shown in FIG. 3A, this soldering apparatus is configured by integrating the light collecting unit 23 and the gas nozzle 27 in the configuration of the soldering apparatus shown in FIG. The lens / gas nozzle unit 32 is structured to be rotatable around the laser optical axis 33 by a driving mechanism (not shown).
[0064]
That is, the cylindrical lens 25 can rotate in an arbitrary direction around the optical axis 33, and the gas nozzle 27 also rotates integrally in the same direction. Further, the circular laser beam 24 is condensed by the cylindrical lens 25 to become the laser beam 26 and finally irradiated as a linear beam 34. The linear beam 34 is also rotated by the rotation of the cylindrical lens 25. Rotate in the same direction.
[0065]
Therefore, as shown in FIG. 2B, even when lead wires are exposed from each side of an electronic component, for example, the FPIC 35, by rotating the lens gas nozzle unit 32 in accordance with the direction of each side, The rectangular gas outlet 29 and the linear beam 34 of the laser light 26 can be made to coincide with the arrangement direction of the lead wires on each side.
[0066]
That is, after soldering by arranging the gas outlet 29 and the linear beam 34 along the arrangement direction 37 of the plurality of lead wires 36 projecting from one side of the FPIC 35, the other direction perpendicular thereto is arranged. The gas outlet 29 and the linear beam 34 can be rearranged and soldered along the arrangement direction 39 of the plurality of lead wires 38 protruding from the side, and by repeating this operation, the arrangement of the FPIC 35, etc. All lead wires can be soldered efficiently without changing.
[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 passed through the solder layer 7 formed in advance on the wiring electrodes 9. And soldered. In this embodiment, the solder material of the solder layer 7 is 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.
[0068]
Nitrogen gas was used as the shielding gas 14, and this nitrogen gas was heated to 250 ° C. by the electric heater 12 and sprayed from the outlet of the nozzle tip 16 under conditions of a pressure of 0.2 MPa and a flow rate of 1.5 NL / min.
[0069]
On the other hand, as the laser oscillator 1, a YAG laser was used, and laser light with an output of 10 W was irradiated for 0.3 seconds (per lead terminal).
[0070]
At the time of 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, and the portion to be soldered with the laser light in that state The solder was melted by spot-irradiating the center of the solder to perform soldering.
[0071]
As a result, the soldering speed could be 0.3 seconds per lead terminal, and there were no solder balls on the soldered printed circuit board 8.
[0072]
In addition, since the spraying direction of the shield gas 14 and the optical axis of the laser beam 4 coincide, it is easy to position the heating spot.
[0073]
【The invention's effect】
As described above, according to the present invention, when soldering an electronic component, the laser beam and the high-temperature shield gas are used in combination, and the optical axis of the laser beam is disposed in the outlet of the gas nozzle for the high-temperature shield gas, and the shield By making the shape of the gas outlet into an elongated slit, it is possible to form a non-oxidizing atmosphere by spraying shield gas at a time along a row of a plurality of lead terminals protruding from the electronic component to preheat or preheat. Therefore, a plurality of lead terminals can be efficiently soldered in a short time by irradiating with laser light in that state.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an embodiment of a soldering apparatus according to the present invention.
2A and 2B show another embodiment of the soldering apparatus according to the present invention, in which FIG. 2A is a partially enlarged view in the vicinity of a gas nozzle, and FIG. 2B is a cross-sectional view taken along the line AA in FIG. .
FIG. 3 is a partially enlarged perspective view in the vicinity of a light collecting unit showing still another embodiment of a soldering apparatus according to the present invention.
FIG. 4 is a chart showing an example of pulse output of laser light in the present invention.
5A and 5B show still another embodiment of a soldering apparatus according to the present invention, in which FIG. 5A is a partially enlarged perspective view in 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 parts
6: Lead terminal
7: Solder layer
8: Printed circuit board
9: Wiring electrode
10: Joint location
11, 27: Gas nozzle
12: Electric heater
13: Introduction port
14: Shield gas
15: High temperature shielding 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

Claims (2)

A lead terminal of an electronic component is installed on the wiring electrode of the printed circuit board, and a laser beam is irradiated to the installation portion of the lead terminal, and a heated shield gas made of an inert gas or a reducing gas is sprayed and soldered. In the method of soldering electronic components to be performed,
The shield gas outlet is formed into a long and narrow slit, and condensing means for condensing the laser beam so as to be a linear beam is provided, and its optical axis is disposed in the shield gas outlet. ,
The shield gas is sprayed onto a portion to be soldered, heated to a temperature lower by 100 to 10 ° C. than the melting temperature of the solder, and the laser light is condensed to form a linear beam in that state, and the shield Pass through the gas outlet and irradiate the part to be soldered with a pulse ,
A soldering method for an electronic component , wherein the shield gas blowing port is rotated in accordance with the arrangement direction of the lead terminals, and the linear beam of the laser light is also rotated together with the blowing port . In an electronic component soldering apparatus that installs a lead terminal of an electronic component on a wiring electrode of a printed circuit board and heats and solders the installation portion of the lead terminal,
A laser beam irradiating means for condensing the laser beam and irradiating a predetermined location;
A shield gas spraying means for spraying a heated shield gas made of an inert gas or a reducing gas to a predetermined location;
The outlet of the shielding gas spraying means has an elongated slit shape,
The laser beam irradiating unit has a condensing unit that condenses the laser beam so as to be a linear beam, and the optical axis of the linear beam formed by the condensing unit is within the outlet of the shield gas blowing unit. It is located in,
A rotating device that rotates together the blowout port of the shielding gas blowing means and the linear beam having an optical axis in the blowout port;
The shield gas is blown to the place to be soldered, heated to a temperature lower by 100 to 10 ° C. than the melting temperature of the solder, and the laser light is pulsed and irradiated to the place to be soldered in that state. An electronic component soldering apparatus characterized by comprising:

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