JP2007289980A - Laser soldering equipment and laser soldering method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide laser soldering equipment, wherein the temperature of each welding member is increased to enable laser soldering by stable heat input. <P>SOLUTION: With two prisms 4 arranged on the optical path of a laser beam 10, and with the one laser beam 10 split into two laser beams, welding members 6, 7 are irradiated with the laser beams respectively, for fusing and solidifying cream solder 8 to join the welding members to each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention irradiates a joining member with a laser beam and indirectly raises the temperature of the solder supplied to or near the joining interface, thereby melting and solidifying the solder to join the joining members together. The present invention relates to an attaching device and a laser soldering method.

  In recent years, laser soldering has been adopted for solder bonding that requires precision bonding. For example, in the manufacture of an optical pickup of an optical disk drive device, laser soldering is employed to solder a light source to a coupling base (see, for example, Patent Document 1).

  Laser soldering is a method in which each joining member is adjusted to a predetermined position in advance and then the solder is supplied, and then laser irradiation is performed to melt and solidify the solder, thereby joining the joining members. FIG. 11 shows a schematic diagram of a conventional laser soldering apparatus.

  As shown in FIG. 11, the conventional laser soldering apparatus includes a laser light source 1 and a lens barrel 2. The lens barrel 2 includes a first plano-convex lens 3 that collimates the laser light from the laser light source 1 and a second plano-convex lens 5 that condenses the laser light 10 from the first plano-convex lens 3. To do.

  Conventionally, as shown in FIG. 11, after the joining members 6 and 7 are adjusted to predetermined positions in advance, cream solder 8 is applied in the vicinity of the joining interface, and the laser light emitted from the lens barrel 2 is applied to the cream solder 8. The joint members 6 and 7 were joined by melting and solidifying the cream solder 8.

  However, when the cream solder is directly irradiated with laser light in this way, the cream solder generally has a high absorption rate of the laser light, so the temperature rises abruptly, and ball solder is generated or solder joints due to bumping There is a risk of causing problems such as outflow and flux scattering.

Therefore, laser soldering has been proposed in which a joining member is irradiated with a laser beam and cream solder is melted and solidified by the heat input. However, in conventional laser soldering, only one of the members to be joined is irradiated with laser light, so that each joining member does not warm evenly, resulting in a difference in temperature. Therefore, depending on the application state of the cream solder, the wettability of the solder may be deteriorated and unbonding may occur.
JP 2005-339767 A

  In view of the above-described problems, the present invention provides a laser beam for irradiating a plurality of laser beams in laser soldering by irradiating a laser beam to melt the solder and bonding the first bonding member and the second bonding member. A laser soldering apparatus and a laser solder capable of increasing the temperature of each joining member by dividing and irradiating a predetermined position of each joining member with a laser, and enabling laser soldering with stable heat input The purpose is to provide an attachment method.

  The laser soldering apparatus according to claim 1 of the present invention is a laser soldering apparatus for irradiating a laser beam to melt the solder and joining the first member and the second member. Laser beam splitting means for splitting the laser beam emitted from the laser light source into a plurality of laser beams, and the plurality of split laser beams at predetermined positions of the first member and the second member, respectively. And a light collecting means for collecting light.

A laser soldering apparatus according to claim 2 of the present invention is the laser soldering apparatus according to claim 1, wherein the laser beam splitting means is a plurality of prisms.
A laser soldering apparatus according to claim 3 of the present invention is the laser soldering apparatus according to claim 2, wherein the prism is disposed within a plane having the optical axis of laser light incident on the prism as a normal line. A moving means for moving is provided.

  A laser soldering apparatus according to claim 4 of the present invention is the laser soldering apparatus according to claim 2 or 3, wherein the incident of the prism with respect to the optical axis of the laser beam incident on the prism. An angle adjusting means for adjusting the angle of the surface is provided.

  A laser soldering apparatus according to claim 5 of the present invention is the laser soldering apparatus according to any one of claims 2 to 4, wherein the optical axis of the laser beam incident on the prism is a normal line. Rotating means for rotating the prism around the optical axis in a plane is provided.

  The laser soldering method according to claim 6 of the present invention is a laser soldering method in which the first member and the second member are joined by irradiating a laser beam to melt the solder. The laser light is divided into a plurality of laser lights, and the divided laser lights are condensed at predetermined positions of the first member and the second member, respectively.

  The laser soldering method according to claim 7 of the present invention is the laser soldering method according to claim 6, wherein a hole or a groove is provided at a predetermined position for condensing the laser beam of at least one member. It is characterized by.

  The laser soldering method according to claim 8 of the present invention is the laser soldering method according to claim 7, wherein NA <180 with respect to the NA of the laser beam when the angle of the hole or groove is θ. -2θ is satisfied.

  According to the present invention, since the first and second members are irradiated with laser, the temperature of each member to be joined can be raised, and laser soldering with stable heat input becomes possible. Also, a plurality of condensing points can be obtained for one laser light source by inserting a plurality of prisms between the laser emission point and the processing point.

  In addition, by adopting a configuration in which each prism can be moved within a plane whose normal is the optical axis of the laser light incident on the prism, the split ratio of the laser light can be arbitrarily determined, and each divided laser light The energy ratio at the light condensing point can be adjusted.

  In addition, the angle of the laser light incident surface of each prism with respect to the optical axis of the laser light incident on the prism can be adjusted, so that the incident angle of the laser light to each prism can be adjusted. The condensing point position of each subsequent laser beam or the interval between the condensing points can be adjusted.

  In addition, it is possible to rotate each prism around the optical axis in a plane with the optical axis of the laser light incident on the prism as a normal line. The position can be adjusted.

  As described above, since the condensing point position and the interval between the condensing points can be adjusted, it becomes possible to irradiate the laser beam at an appropriate position regardless of the relative position of the member to be joined. Soldering is possible.

  In addition, a hole or groove is provided at the laser irradiation position of the member to be joined, and solder joining is performed by irradiating the laser beam to the hole, so that the surface accuracy (surface roughness) of each member and the material are stable. It is possible to ensure heat input and solder wettability, and appropriate solder bonding is possible.

  Further, when the angle of the hole or groove is θ, the laser light reflected in the hole or groove is re-opened by satisfying the relationship of NA <180−2θ with respect to the NA of the laser light (see FIG. 8). Or since it hits the member surface in a groove | channel, the laser irradiation effect of 2 times or more can be acquired substantially. Therefore, it is possible to more stably absorb the heat amount of the laser beam in the member without depending on the fluctuation of the laser output, the surface accuracy (surface roughness) of the member, and the material of the member surface, thereby reducing solder defects. Can do.

  Hereinafter, a laser soldering apparatus and a laser soldering method according to embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram of a laser soldering apparatus according to the present embodiment. FIG. 2 is a schematic view of the laser soldering apparatus shown in FIG. 1 as viewed from the side.

  As shown in FIGS. 1 and 2, the laser soldering apparatus includes a laser light source 1 and a lens barrel 2. For example, a laser chip or the like is used as the laser light source. The lens barrel 2 includes a first plano-convex lens 3 that collimates the laser light from the laser light source 1, two prisms 4 for dividing the laser light 10 from the first plano-convex lens, A second plano-convex lens 5 that condenses laser light (parallel light) from the prism 4 is included. The optical components in the laser light source 1 and the lens barrel 2 are arranged so that the divided laser light is irradiated to the predetermined positions of the joining members 6 and 7 as the first and second members.

  As described above, in this embodiment, the two prisms 4 are used as the laser beam dividing means for dividing the laser beam emitted from the laser light source into a plurality of laser beams. Further, the plano-convex lens 5 is used as a condensing means for condensing a plurality of laser beams divided by the two prisms 4 at predetermined positions of the joining members 6 and 7, respectively.

  Further, the joint surface 9 of the prism is parallel to the optical axis of the laser light incident on the prism 4. Thus, in this embodiment, two prisms are arranged on the laser light path, and the laser light is divided into two laser lights by these prisms.

  Here, the case where a triangular prism is used as shown in FIG. 2 will be described as an example, but of course, the shape of the prism is not limited to a triangular prism. For example, a prism of a triangular pyramid to a polygonal pyramid is used. It may be used. Moreover, although the case where two plano-convex lenses are used will be described, the present invention is not limited to this.

  Further, a case where one laser beam is divided into two laser beams using two prisms and irradiated onto each of the two bonding members will be described. However, when there are two or more bonding members, In the case where a plurality of laser beams are irradiated to one joining member, two or more prisms may be provided to divide one laser beam into two or more laser beams.

  Hereinafter, solder bonding using the laser soldering apparatus will be described. First, after adjusting the joining members 6 and 7 to a predetermined position in advance, the cream solder 8 is applied in the vicinity of the joining interface, and two laser beams emitted from the lens barrel 2 are applied to the predetermined joining members 6 and 7. Irradiate the position (see FIG. 5 for the positional relationship of the bonding member 6, the bonding member 7, and the cream solder 8). Note that the solder as a bonding material for bonding the members is not limited to cream solder.

  At this time, the laser light emitted from the laser light source 1 enters the prism 4 as parallel light 10 by the first plano-convex lens 3 in the lens barrel 2, and is split into two parallel light by each prism 4. Is done. The second plano-convex lens 5 collects the two parallel lights and irradiates them at predetermined positions of the joining members 6 and 7.

  In this way, by condensing the laser beam on each of the members to be joined, the joining members are heated, and heat is transferred to the solder by heat conduction to melt and solidify, and the joining members 6 and 7 are joined. The Although the case where cream solder is provided near the joint interface has been described here, it goes without saying that the case where cream solder is provided at the joint interface can also be implemented in the same manner.

  As described above, a plurality of condensing points can be obtained for one laser light source 1 by inserting the two prisms 4 between the laser emission point and the processing point. Since each of the joining members 6 and 7 is irradiated with laser simultaneously, the temperature of each joining member 6 and 7 can be raised simultaneously, and laser soldering with stable heat input becomes possible.

  Next, adjustment of the laser beam division ratio in the laser soldering apparatus of the present embodiment will be described with reference to FIG. FIG. 3 is a schematic view of the laser soldering apparatus according to the present embodiment in a case where each prism is moved within a plane whose normal is the optical axis of the laser light incident on the prism.

  The laser soldering apparatus includes a mechanism (moving means: not shown) that moves each prism within a plane whose normal is the optical axis of the laser beam incident on the prism. By moving the triangular prisms, it is possible to change the ratio of the irradiation area of the laser beam to each prism and arbitrarily determine the split ratio of the laser beam.

  As shown in FIG. 3, each prism 4 is integrated and can be translated on a plane whose normal is the optical axis of the laser light incident on the prism 4. By this parallel movement, the position of the joint surface 9 of the prism with respect to the optical axis of the laser beam 10 incident on the prism 4 can be moved, and the division ratio of the laser beam can be adjusted. Since the split ratio of the laser beam corresponds to the energy ratio of the laser beam, the energy ratio at the condensing point of each laser beam after splitting can be adjusted by adjusting the position of the prism.

  In this way, each prism can be moved within a plane having the optical axis of the laser beam 10 as a normal line, so that the split ratio of the laser beam is adjusted in consideration of the heat capacity of the bonding member, and each bonding member The amount of change in temperature or the maximum reached temperature can be made the same or substantially the same, and the wettability of the solder to each joining member becomes equivalent or substantially the same, so that solder defects can be reduced.

  Next, adjustment of the position of the condensing point of each laser beam after the division or the interval between the condensing points in the laser soldering apparatus of the present embodiment will be described. In laser soldering that joins joining members by irradiating them with laser light, the laser irradiation position varies due to the accuracy of adjusting the joining member to a predetermined position and the finishing accuracy of the joining member, and the solder is sufficient. Cannot absorb a sufficient amount of heat and may cause unmelting of the solder.

  For example, when a light source is soldered to a coupling base in the manufacture of an optical pickup of an optical disk drive device, if the finishing accuracy of each bonding member, particularly the bonding position accuracy of the LD element is low, the light emitting position of the LD element is set to an appropriate position When adjusted, there is a variation in the temporary fixing position of the light source with respect to the coupling base, and the laser beam for melting the solder cannot be irradiated to the optimum position, which may cause solder failure.

  Therefore, in order to solve this problem, in the laser soldering apparatus according to the present embodiment, the position of the condensing point of each laser beam after division or the interval between the condensing points can be adjusted, so that the joining member Even if the relative position of the laser beam fluctuates, it is possible to easily irradiate the laser beam to an appropriate position.

  First, the case of adjusting the angle of the laser light incident surface of each prism 4 with respect to the optical axis of the laser light incident on the prism 4 will be described with reference to FIGS. FIG. 4 is a schematic diagram when the angle of the laser beam incident surface of each prism with respect to the optical axis of the laser beam incident on the prism is adjusted in the laser soldering apparatus of the present embodiment. FIG. 5 is a schematic diagram showing the movement of the condensing point of each laser beam after splitting by adjusting the angle of the laser beam incident surface of each prism, and the laser irradiation surface is viewed from above.

  The laser soldering apparatus includes a mechanism (angle adjusting means: not shown) that adjusts the angle of the laser light incident surface of each prism with respect to the optical axis of the laser light incident on the prism. The incident angle to the prism can be adjusted, and the position of the condensing point of each laser beam after the division or the interval between the condensing points can be adjusted.

  As shown in FIG. 4, each of the prisms 4 can rotate around an axis 11 perpendicular to the bonding surface 9, and the angle (tilt angle) of the incident surface of each prism 4 with respect to the optical axis of the laser beam 10. ) Can be adjusted to adjust the incident angle of the two laser beams emitted from each prism 4 to the plano-convex lens 5. The incident angle to the plano-convex lens 5 is determined by adjusting the tilt angle of each prism 4 in order to determine the position of the condensing point of the laser light after exiting the plano-convex lens 5, as shown in FIG. The position of the condensing point 12 of each laser beam can be adjusted with respect to the direction 13 parallel to. Moreover, the space | interval between the condensing points 12 can be adjusted by adjusting the position of the condensing point 12 of each laser beam.

  In this way, by adopting a configuration in which the angle of the laser beam incident surface of each prism with respect to the optical axis of the laser beam 10 can be adjusted, the incident angle of the laser beam to each prism can be adjusted. The position of the condensing point of the laser beam or the interval between the condensing points can be adjusted.

  Next, a case where each prism is rotated around the optical axis in a plane having the optical axis of laser light incident on the prism as a normal line will be described with reference to FIGS. FIG. 6 is a schematic view of the laser soldering apparatus according to the present embodiment when the prisms are integrally rotated around the optical axis of the laser light incident on the prism, and the prism is viewed from above. . FIG. 7 is a schematic diagram showing movement of the condensing point of each laser beam after splitting by rotating each prism integrally around the optical axis of the laser beam incident on the prism. Seen from above.

  The laser soldering apparatus includes a mechanism (rotating means: not shown) that rotates each prism around the optical axis in a plane with the optical axis of the laser light incident on the prism as a normal line. The position of the condensing point of each divided laser beam can be adjusted.

  As shown in FIG. 6, the prisms 4 can be rotated together in the rotation direction 15 around the optical axis 14 of the laser light 10. By adjusting the amount of rotation of the prism, the incident position of the laser beam 10 on each prism 4 changes, the incident position of each laser beam after splitting on the plano-convex lens 5 changes, and the bending position of the laser beam changes. Change. Therefore, as shown in FIG. 7, the condensing point 12 of each divided laser beam moves in the direction 16 about the optical axis 14 of the laser beam 10 according to the amount of rotation of the prism.

  In this way, the prisms can be rotated around the optical axis of the laser beam 10 in a plane having the optical axis of the laser beam 10 as a normal line, so that the condensing points of the divided laser beams can be obtained. The position can be adjusted.

  As described above, according to the present embodiment, the position of the condensing point of each laser beam after the division or the interval between the condensing points can be adjusted. Therefore, it is possible to irradiate a laser beam at an appropriate position, and an appropriate solder joint is possible. Therefore, even when solder bonding is performed after adjusting the mutual position of the bonding members, it is possible to always irradiate the laser beam at the optimum position, and to reduce solder defects.

  Next, a case where a hole or groove is provided at a predetermined laser irradiation position of the bonding member and the hole or groove is irradiated with laser light will be described. FIG. 8 is a schematic diagram of a joining cross section of the joining member in the present embodiment.

  As shown in FIG. 8, a hole or groove 17 is provided at the laser irradiation position of the bonding member 6 and the laser beam is irradiated perpendicularly to the surface of the bonding member. By providing the hole or groove 17, the laser light irradiated in the hole or groove 17 is reflected in the back direction, and multiple reflections are made in the hole or groove 17. Regardless, the joining member 6 can absorb laser light at a constant rate, and it becomes possible to prevent insufficient heating or excessive heating during melting of the solder, thereby reducing solder defects.

  The selection of whether to provide a hole or a groove may be determined according to the spot shape of the laser beam to be used. For example, if the spot shape is rectangular, the groove shape is more preferable than the hole shape because the gain is higher. Further, the size of the hole or groove is preferably equal to or smaller than the spot diameter of the laser light in consideration of the multiple reflection of the laser light in the hole or groove. The direction of the groove is adjusted to the spot shape so that the laser beam is irradiated into the groove.

  Further, when the hole or groove shape is triangular, as shown in FIG. 8, if the angle of the hole or groove 17 is θ, the relationship NA <180−2θ with respect to the NA of the laser beam is satisfied. Is preferred. In the present invention, as shown in FIG. 8, the angle at which the laser beam collected by the plano-convex lens 5 is collected is NA.

  By satisfying the relationship of NA <180-2θ, the laser light irradiated in the hole or groove is reflected in the back direction, and the laser light reflected in the hole or groove has different member surface regions in the hole or groove. Therefore, it is possible to obtain a laser irradiation effect that is substantially twice or more. For example, as shown in FIG. 9, when NA = 180−θ, the reflected laser beam is guided to the outside of the hole or groove 17 without hitting a different member surface region.

  Multiple times of laser light reflection (absorption of multiple times of laser light) makes it possible to more stably apply laser light to a member without depending on fluctuations in laser output, surface accuracy (surface roughness) of the member, or material of the member surface. Since the amount of heat can be absorbed, solder defects can be reduced. Note that, when the angle of θ with respect to NA is smaller, the laser beam is reflected in the back direction, so that the absorption efficiency can be increased.

  In addition, by providing a hole or groove at the laser irradiation position, it becomes possible to perform very local heating in the vicinity of the solder welded portion, and it is possible to reduce the influence of thermal strain and thermal deformation. can do.

  In addition, by providing the hole or groove at the laser irradiation position, the laser beam absorption rate of the bonding member is increased, and solder melting can be performed with lower energy than in the case where the hole or groove is not provided. Therefore, it is possible to minimize deterioration over time of a laser chip or the like used as a laser light source.

  As described above, a hole or groove is provided at a predetermined laser irradiation position of a member to be bonded, and laser bonding is performed on the hole or groove to perform surface bonding (surface roughness) and material of each bonding member. Therefore, stable heat input and solder wettability can be ensured, and appropriate solder bonding is possible.

  Here, the case where the hole or groove is provided only in the joining member 6 has been described, but it is optional depending on conditions such as the material of the joining member to be used and the application position of the cream solder. It is sufficient to provide a hole or groove in at least one or more joining members.

  In addition, although the triangular hole or groove has been described as an example here, the shape is not limited to a triangular shape, and may be a square, polygonal, U-shaped, or the like, and laser light is multiply reflected inside the hole or groove. Any shape can be used. For example, FIG. 10 shows a bonding cross section in the case where a square hole or groove is provided.

  According to the laser soldering apparatus and the laser soldering method of the present invention, it is possible to perform laser soldering with stable heat input. For example, in manufacturing an optical pickup of an optical disc drive apparatus, a light source is soldered to a coupling base. It is useful for solder joints that require precision joining.

Schematic diagram of laser soldering apparatus in an embodiment of the present invention Schematic diagram of a side surface of a laser soldering apparatus according to an embodiment of the present invention The schematic diagram for demonstrating the parallel displacement of the prism in embodiment of this invention The schematic diagram for demonstrating angle adjustment of the entrance plane of the prism in embodiment of this invention Schematic diagram for explaining converging point movement of laser light by adjusting the angle of the incident surface of the prism in the embodiment of the present invention The schematic diagram for demonstrating rotation of the prism in embodiment of this invention The schematic diagram for demonstrating the condensing point movement of the laser beam by rotation of the prism in embodiment of this invention Schematic diagram of the joining cross section of the joining member in the present embodiment Schematic diagram of the joining cross section of the joining member in the present embodiment Schematic diagram of the joining cross section of the joining member in the present embodiment Schematic diagram of conventional laser soldering equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Laser light source 2 Lens tube 3, 5 Plano-convex lens 4 Prism 6, 7 Joining member 8 Cream solder 9 Joining surface 10 Laser beam (parallel light) before division | segmentation
DESCRIPTION OF SYMBOLS 11 Rotating shaft 12 Condensing point 13, 16 Moving direction of condensing point 14 Optical axis of laser beam before division 15 Rotating direction 17 Hole or groove

Claims (8)

  A laser soldering apparatus for irradiating a laser beam to melt a solder to join a first member and a second member, wherein one laser light source and a plurality of laser beams emitted from the laser light source A laser beam splitting unit that splits the beam into light; and a focusing unit that collects the divided laser beams at predetermined positions of the first member and the second member, respectively. Laser soldering device.   2. The laser soldering apparatus according to claim 1, wherein the laser beam splitting means is a plurality of prisms.   3. The laser soldering apparatus according to claim 2, further comprising moving means for moving the prism within a plane having the normal axis of the laser beam incident on the prism.   4. The laser soldering apparatus according to claim 2, further comprising angle adjusting means for adjusting an angle of an incident surface of the prism with respect to an optical axis of laser light incident on the prism.   5. The rotating device according to claim 2, further comprising a rotating unit configured to rotate the prism around the optical axis in a plane having a normal to the optical axis of the laser beam incident on the prism. Laser soldering equipment.   A laser soldering method for joining a first member and a second member by irradiating a laser beam to melt the solder, dividing one laser beam into a plurality of laser beams, and dividing the divided laser beams A laser soldering method comprising condensing light at predetermined positions of the first member and the second member, respectively.   7. The laser soldering method according to claim 6, wherein a hole or a groove is provided at a predetermined position for condensing the laser beam of at least one member. 8. The laser soldering method according to claim 7, wherein when the angle of the hole or groove is θ, the relationship NA <180−2θ is satisfied with respect to the NA of the laser beam.

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