JP2009297737A - Laser welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform satisfactory welding when laser-welding a projecting tip end of a lead projecting from an electronic component to a base material by a laser-welding method, without plating the projecting tip end of the lead after cutting. <P>SOLUTION: The laser-welding method includes: a first step of applying plating 20a to the outer surface of a plate-like frame material 23, which has a lead 20 and a frame 22 integrally connected together; a second step of mounting the lead 20 in a state of the frame material 23 on an electronic component 10; a third step of cutting and separating the lead 20 from the frame 22; and a fourth step of laser-welding the lead 20 to a base material 100. In the outer surface of the frame material 23, a hole 24 is formed which is depressed lower than the outer surface of the frame material 23. The hole 24 is formed such that a side thereof extending in the depth direction becomes a projecting tip end 21 of the lead 20 after cutting. In the first step, the plating 20a is also applied to the side of the hole 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a laser welding method for laser welding a lead provided protruding from an electronic component to a base material.

In general, in this type of laser welding method, a plate-like lead made of Cu or the like is provided on an electronic component so as to protrude from the electronic component, and at the same time, the surface of the lead is plated with Sn, Ni, Au, solder or the like. Then, this is laser-welded to the substrate at the projecting tip side of the lead (see, for example, Patent Document 1 and Patent Document 2).
JP 10-137957 A JP 2001-87877 A

  The present inventor has conducted intensive studies on this type of laser welding method based on the above-described prior art. 7 and 8 are process diagrams showing the laser welding method in the prototype of the present inventors.

  7A is a schematic plan view showing the lead 20 before cutting, FIG. 7B is a schematic plan view of the lead 20 after cutting, and FIG. 7C is a schematic cross-sectional view along A1-A1 of FIG. d) is a schematic plan view of the protruding tip 21 of the lead 20 as viewed from the direction of arrow A2 in FIG. In FIG. 7A, the lead 20 is separated from the frame 22 (the portion other than the lead 20 in the frame member 23) by cutting the frame member 23 along the broken line in the drawing. FIG. 8 is a schematic sectional view showing the laser welding process.

  In this method, first, plating 20a is applied to the outer surface of the frame member 23 on a plate-like frame member 23 formed by integrally connecting the leads 20 to the frame 22 (first step). In FIG. 7 and the following plan views, in order to identify the presence or absence of the plating 20a, the surface of the plating 20a is hatched for the sake of convenience, and the surface without the plating 20a is not hatched.

  Next, the lead 20 is provided on the electronic component 10 in the state of the frame member 23 to which the plating 20a has been applied (second step). The state of the workpiece immediately after the completion of the second step is shown in FIG.

  Thereafter, the lead 20 is cut and separated from the frame 22 at the broken line portion in FIG. Thereby, the lead 20 protruding from the electronic component 10 is formed (third step). As a result, the cut surface of the lead 20 from the frame 22 forms the protruding tip 21, and the protruding tip 21 of the lead 20 is plated on the protruding tip 21 as shown in FIGS. There is no 20a.

  Then, as shown in FIG. 8, the portion of the plate-like lead 20 on the protruding tip 21 side and the base material 100 are overlapped and laser-welded (fourth step). At this time, the protruding tip portion 21 of the lead 20 has a surface in which the base material is exposed without the plating 20a. Therefore, in the protruding tip portion 21, the laser absorptance is lowered and the weldability is lowered. .

  As a countermeasure against this, the present inventor considered that the plating 20a is applied to the protruding tip 21 before welding on the lead 20 after the cutting as shown in FIG. However, in this case, there is a problem that man-hours are required for the plating before welding.

  The present invention has been made in view of the above problems, and in a laser welding method in which a lead provided protruding from an electronic component is laser-welded to a substrate at a protruding tip portion side of the lead, the lead after cutting The object is to enable good welding without plating the protruding tip of the plate.

  In order to achieve the above object, in the first aspect of the present invention, the frame material (23) is compared with the plate-shaped frame material (23) formed by integrally connecting the lead (20) to the frame (22). A first step of plating (20a) on the outer surface of the substrate, a second step of providing the lead (20) on the electronic component (10) in the state of the frame member (23), and a first and second step. Thereafter, the lead (20) is cut and separated from the frame (22) to form a lead (20) protruding from the electronic component (10), and then the lead (20). And a fourth step of performing laser welding with the base material (100). As the frame material (23), holes (24, 26) recessed from the outer surface are formed on the outer surface of the frame material (23). Forming and depth direction in the hole (24, 26) In the first step, the extending side surface is configured as a protruding tip portion (21) after cutting the lead (20), and in the first step, the side surfaces of the holes (24, 26) are also plated (20a). It is characterized by doing.

  According to this, since the plating (20a) is applied to the side surfaces of the holes (24, 26) to be the projecting tip portion (21) of the lead (20), the projecting tip portion of the lead (20) ( 21) is plated (20a), so that it is possible to perform good welding without plating the protruding tip (21) of the lead (20) after cutting.

  Here, the hole (24) may be a through hole penetrating the frame member (23) as in the invention described in claim 2, or the hole (24) may be formed as in the invention described in claim 3. May be a recess (26) recessed in the thickness direction of the frame material (23).

  Further, as in the invention described in claim 4, the opening shape of the holes (24, 26) has an arc shape having a radius of curvature equivalent to the beam diameter of the laser at the time of laser welding, and a portion of the arc shape. May be configured as the protruding tip (21).

  According to this, the shape of the protruding tip portion (21) of the lead (20) after cutting can be easily made into a shape having a large laser irradiation area.

  In addition, the code | symbol in the bracket | parenthesis of each means described in the claim and this column is an example which shows a corresponding relationship with the specific means as described in embodiment mentioned later.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings in order to simplify the description.

(First embodiment)
1 and 2 are process diagrams showing a laser welding method according to the first embodiment of the present invention. In FIG. 1, (a) is a schematic plan view showing a lead 20 before cutting, and (b) is cutting. (C) is a schematic cross-sectional view of B1-B1 in (b), and (d) is a schematic plan view of the protruding tip 21 of the lead 20 as viewed from the direction of arrow B2 in (b). is there. In FIG. 1A, the lead 20 is separated from the frame 22 by cutting the frame member 23 along the broken line in the figure. FIG. 2 is a schematic sectional view showing a laser welding process.

  First, plating 20a is applied to the outer surface of the frame material 23 on a plate-like frame material 23 formed by integrally connecting the leads 20 to the frame 22 (first step). The frame material 23 is a plate material made of copper or the like, and is formed by planarly patterning a plurality of leads 20 and a frame 22 connecting the leads 20.

  Here, in the subsequent step, the frame material 23 is cut along the broken line in FIG. 1A, whereby the individual leads 20 are separated from the frame 22 and become independent. Holes 24 and 25 as through holes penetrating in the thickness direction are formed in the frame member 23, and the patterns of the leads 20 and the frame 22 are partitioned by the holes 24 and 25.

  Here, as can be seen from the broken line in FIG. 1A, the holes 24 and 25 are the first hole 24 that defines the protruding tip 21 of the lead 20 and the electronic component 10 side of the lead 20. A second hole 25 that defines a side surface in the longitudinal direction is formed.

  That is, in the first hole 24, a hole recessed from the outer surface in the vicinity of the portion of the frame member 23 that becomes the protruding tip 21 of the lead 20, here the first hole 24 as a through hole. The side surface which is a surface extending in the depth direction of the first hole 24 constitutes the protruding tip 21 of the lead 20 after cutting. Each lead 20 is connected to the frame 22 only by a side surface portion extending in parallel with the protruding direction.

  The plating 20 a is applied to the outer surface of the frame member 23, that is, both the front and back plate surfaces of the frame member 23 and the side surfaces of these holes 24 and 25. The plating 20a is made of a plating that easily absorbs laser so as to improve weldability by laser welding performed in a subsequent process.

  For example, the plating 20a includes plating of Sn, Ni, solder, Au, or the like. Such plating 20a can be formed by a general plating method such as electroplating or electroless plating.

  Next, the lead 20 is provided on the electronic component 10 in the state of the frame member 23 (second step). This state is shown in FIG. The electronic component 10 is, for example, a mold IC in which an IC chip is sealed with a mold resin. The electronic component 10 and the lead 20 can be connected by, for example, wire bonding, solder, bump bonding, press-fitting, fitting, and fastening.

  The attachment of the frame member 23 to the electronic component 10 may be performed before the plating 20a is applied to the frame member 23. In this case, the plating 20a may be applied to the portion of the frame member 23 protruding from the electronic component 10 as described above.

  Thus, after performing the first and second steps, the lead 20 protruding from the electronic component 10 is formed by cutting and separating the lead 20 from the frame 22 (third step). One cut lead 20 after the third step is shown in FIGS.

  As shown in FIGS. 1B to 1D, after the lead 20 is cut, the lead 20 is a plate-like member provided so as to protrude from the electronic component 10. The surface 20 is plated with 20a.

  In the present embodiment, since the plating 20a is also formed on the side surfaces in the depth direction of the holes 24 and 25 in the formation of the plating 20a on the frame member 23, the plating 20a is naturally formed on the protruding tip 21 of the lead 20. Is given. Incidentally, conventionally, as shown in FIG. 7, the cut surface from the frame of this lead constitutes a protruding tip portion, and the protruding tip portion has no plating.

  In the present embodiment, the plating 20a is also applied to the side surface portion of the lead 20 that extends parallel to the protruding direction. However, the plating 20a does not exist on the cut surface from the frame 22 in the side surface portion. A base material such as copper constituting the lead 20 is exposed.

  Next, in this method, as shown in FIG. 2, laser welding is performed between the plate-like lead 20 and the substrate 100 (fourth step). Here, examples of the base material 100 include a lead frame and a bus bar, and the same plating 20a is applied to the surface of the base material 100. Specifically, a portion of the plate-like lead 20 on the protruding tip 21 side and the base material 100 are overlapped, and these are laser welded by a YAG laser or the like. The base material 100 may not have the plating 20a.

  At this time, in this embodiment, since the plating tip 20a is applied to the protruding tip portion 21 of the lead 20, good laser weldability is ensured even at the protruding tip portion 21. Therefore, according to this welding method, it is possible to perform good laser welding without plating the protruding tip 21 of the lead 20 after the lead 20 is cut.

(Second Embodiment)
FIGS. 3A and 3B are process diagrams showing a laser welding method according to the second embodiment of the present invention, in which FIG. 3A is a schematic plan view showing a lead 20 before cutting, and FIG. 3B is a drawing after cutting. (C) is a C1-C1 schematic sectional view of (b), and (d) is a schematic plan view of the protruding tip portion 21 of the lead 20 as viewed from the direction of arrow C2 of (b). In FIG. 3A as well, the lead 20 is separated from the frame 22 by cutting the frame member 23 along the broken line in FIG.

  In the first embodiment, the first hole 24 is formed as a through hole penetrating the frame material 23 on the outer surface of the frame material 23, and the side surface extending in the depth direction of the hole in the first hole 24 is The protruding tip portion 21 after the cutting of the lead 20 was made.

  Since each lead 20 is connected to the frame 22 only by a side surface portion extending in parallel with the protruding direction, the cut surface of the lead 20 after cutting is formed only on the side surface portion, and the protruding tip portion 21 is formed. Was not formed. Therefore, in the first embodiment, the plating 20 a is applied to the entire protruding tip 21 of the lead 20.

  On the other hand, in this embodiment, as shown in FIG. 3A, the side surface of the first hole 24 extending in the depth direction of the hole becomes the protruding tip 21 after the lead 20 is cut. Although it is the same as that of the said 1st Embodiment, it is different from the said 1st Embodiment that a part of the protrusion front-end | tip part 21 is connected with the flame | frame 22.

  Here, as shown in FIG. 3A, both ends of the protruding tip 21 in the width direction of the lead 20 are connected to the frame 22, and the center of the protruding tip 21 in the width direction of the lead 20 is connected. Is configured as the side surface in the first hole 24.

  In this case, as shown in FIGS. 3 (b) to 3 (d), after cutting the lead 20, a part of the protruding tip 21, here cut surfaces at both ends of the protruding tip 21 in the width direction of the lead 20. Is formed, and the base material is exposed without being plated 20a on the cut surface.

  However, since the plating 20a is applied to the central portion in the width direction of the lead 20 at the protruding tip portion 21 by the first hole 24, the protruding tip portion after the cutting of the lead 20 also in this embodiment. It is possible to weld better than the conventional one without plating 21.

(Third embodiment)
4A and 4B are process diagrams showing a laser welding method according to the third embodiment of the present invention, in which FIG. 4A is a schematic plan view showing a lead 20 before cutting, and FIG. (C) is a schematic plan view of the lead 20 after cutting, (d) is a schematic cross-sectional view of D1-D1 of (c), and (e) is (c). It is a schematic plan view of the protrusion front-end | tip part 21 of the lead 20 seen from the arrow D2 direction. In FIG. 4A as well, the lead 20 is separated from the frame 22 by cutting the frame member 23 along the broken line in FIG.

  In the first and second embodiments, the first hole 24 is provided as a through-hole as a hole whose side surface extending in the depth direction becomes the protruding tip 21 after cutting the lead 20, but in this embodiment, The difference from the first embodiment is that the concave portion 26 that is recessed in the thickness direction of the frame member 23 is formed as the hole instead of the through hole.

  Here, as shown in FIGS. 4A and 4B, the recess 26 is a groove provided on the outer surface of the portion of the frame material 23 that becomes the protruding tip 21 of the lead 20. Further, here, the groove has a V-shaped cross-sectional shape in the depth direction, but the groove shape is not particularly limited, and may be, for example, a U-shape.

  As shown in FIG. 4, the side surface extending in the depth direction of the recess 26 as the groove is configured as a protruding tip 21 after the lead 20 is cut. In this case, in the first step of applying the plating 20a, the plating 20a is also applied to the inside of the recess 26, and the plating 20a is formed on the side surface of the recess 26.

  In the present embodiment, the protruding tip 21 of the lead 20 and the frame 22 are connected to the bottom of the recess 26 in the frame material 23 before cutting. That is, in the present embodiment, a part of the projecting tip 21 is connected to the frame 22 as in the second embodiment.

  In addition, in the second embodiment, both ends of the protruding tip 21 except for the central portion in the width direction of the lead 20 are connected to the frame 22. A portion near the other end excluding a portion near one end along the thickness direction of the lead 20 is connected to the frame 22.

  Therefore, in the present embodiment, in the third step of cutting and separating the lead 20 from the frame 22, the bottom side of the concave portion 26 in the frame material 23 is cut. In the present embodiment, in addition to the recess 26, the lead 20 is connected to the frame 22 at a side surface extending in parallel with the protruding direction, as in the above embodiment, and thus this portion is also cut.

  In the case of this embodiment, as shown in FIGS. 4C to 4E, after cutting the lead 20, a part of the protruding tip 21, here, the thickness of the lead 20 at the protruding tip 21. Plating 20a is applied to a portion near one end along the direction, a cut surface is formed on a portion near the other end, and the base material is exposed on the cut surface without being plated 20a.

  As described above, according to the present embodiment, since the plating 20a is applied to the protruding tip 21 near the one end along the thickness direction of the lead 20, the lead 20 is also cut in this embodiment. It is possible to perform better welding than before without plating the protruding tip 21.

(Fourth embodiment)
FIGS. 5A and 5B are process diagrams showing a laser welding method according to the fourth embodiment of the present invention, in which FIG. 5A is a schematic plan view showing a lead 20 before cutting, and FIG. 5B is a drawing after cutting. FIG. 2C is a schematic plan view of the lead 20, FIG. 3C is a schematic cross-sectional view taken along line E1-E1 in FIG. 2B, and FIG. In FIG. 5A as well, the lead 20 is separated from the frame 22 by cutting the frame member 23 along the broken line in FIG.

  As shown in FIG. 5, in this embodiment, the protruding tip 21 of the lead 20 is defined by the first hole 24 as a through hole in the same manner as in the first embodiment. The point which protrudes 20 protrusion front-end | tip parts 21 to the 1st hole 24 is different from the said 1st Embodiment.

  In other words, in the present embodiment, the side surface of the first hole 24 is projected from the frame member 23, so that the connecting portion between the side surface portion extending in parallel with the projecting direction of the lead 20 and the frame 22 is the projecting tip. It is assumed that it is separated from the part 21.

  Thereby, after cutting, the cut surface formed on the side surface portion of the lead 20, that is, the surface on which the base material is exposed without the plating 20 a, is separated from the protruding tip portion 21. In laser welding, since the protruding tip 21 and the cut surface at which the base material is exposed are separated from each other rather than adjacent to each other, the laser absorbing property at the protruding tip 21 is excellent. It is preferable in terms of improvement.

(Fifth embodiment)
6A and 6B are process diagrams showing a laser welding method according to the fifth embodiment of the present invention, in which FIG. 6A is a schematic plan view showing a lead 20 before cutting, and FIG. 6B is a drawing after cutting. (C) is F1-F1 schematic sectional drawing of (b), (d) is a schematic plan view of the protrusion front-end | tip part 21 of the lead 20 seen from the arrow F2 direction of (b). In FIG. 6A as well, the lead 20 is separated from the frame 22 by cutting the frame member 23 along the broken line in FIG.

  As shown in FIG. 6, in the present embodiment, the protruding tip 21 of the lead 20 is defined by the first hole 24 as a through hole in the same manner as in the first embodiment. The point which made 20 protrusion front-end | tip parts 21 into the circular arc shape equivalent to the beam shape of the laser at the time of laser welding is different from the said 1st Embodiment.

  In this case, in the opening shape of the first hole 24, the portion of the first hole 24 whose side surface constitutes the protruding tip 21 of the lead 20 has a radius of curvature equivalent to the laser beam diameter during laser welding. An arc shape having Thereby, after cutting, the arc-shaped portion is configured as the protruding tip 21.

  The beam shape of the laser, that is, the cross-sectional shape orthogonal to the irradiation direction of the beam is circular, and the beam diameter is about 0.3 mm to 1.5 mm in diameter. Therefore, even in the arc shape, an arc is formed so as to have the same radius of curvature as the beam diameter. As a result, the laser irradiation area can be increased at the protruding tip 21 of the lead 20 after cutting, leading to improved weldability.

  Further, the present embodiment can be applied even when the hole constituting the protruding tip portion 21 of the lead 20 is a recess as in the third embodiment. In this case, the opening shape of the concave portion may be an arc shape having a radius of curvature equivalent to the beam diameter of the laser.

(Other embodiments)
The openings 24 and 26 provided in the frame member 23 and constituting the protruding tip 21 of the lead 20 after cutting are not limited to the quadrangle or groove shape shown in the above figure. Various polygons and circles can be appropriately changed.

It is process drawing which shows the laser welding method which concerns on 1st Embodiment of this invention, (a) is a schematic plan view which shows the lead before a cutting process, (b) is a schematic plan view of the lead after a cutting process, (c ) Is a B1-B1 schematic cross-sectional view of (b), and (d) is a schematic plan view taken in the direction of arrow B2 of (b). It is a schematic sectional drawing which shows the laser welding process which concerns on 1st Embodiment. It is process drawing which shows the laser welding method which concerns on 2nd Embodiment of this invention, (a) is a schematic plan view which shows the lead before a cutting process, (b) is a schematic plan view of the lead after a cutting process, (c ) Is a C1-C1 schematic cross-sectional view of (b), and (d) is a schematic plan view as viewed in the direction of arrow C2 of (b). It is process drawing which shows the laser welding method which concerns on 3rd Embodiment of this invention, (a) is a schematic plan view which shows the lead before a cutting process, (b) followed the longitudinal direction of the lead in (a). (C) is a schematic plan view of a lead after cutting, (d) is a schematic cross-sectional view taken along D1-D1 of (c), and (e) is a schematic plan view taken along arrow D2 of (c). It is process drawing which shows the laser welding method which concerns on 4th Embodiment of this invention, (a) is a schematic plan view which shows the lead before a cutting process, (b) is a schematic plan view of the lead after a cutting process, (c) ) Is an E1-E1 schematic cross-sectional view of (b), and (d) is a schematic plan view as viewed in the direction of arrow E2 of (b). It is process drawing which shows the laser welding method which concerns on 5th Embodiment of this invention, (a) is a schematic plan view which shows the lead before a cutting process, (b) is a schematic plan view of the lead after a cutting process, (c) ) Is an F1-F1 schematic cross-sectional view of (b), and (d) is a schematic plan view as viewed in the direction of arrow F2 of (b). It is process drawing which shows the laser welding method in this inventor's trial production, (a) is a schematic plan view which shows the lead before a cutting process, (b) is a schematic plan view of the lead after a cutting process, (c) is ( (b) A1-A1 schematic sectional drawing, (d) is an A2 arrow schematic plan view of (b). It is a schematic sectional drawing which shows the laser welding process in this inventor's trial manufacture. It is a schematic sectional drawing which shows the state which plated the protrusion front-end | tip part before welding with respect to the lead after a cutting process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Electronic component 20 Lead 20a Plating 21 Lead tip 22 Frame 23 Frame material 24 First hole 26 Recess 100 Base material

Claims (4)

A plate-like lead (20) provided so as to protrude from the electronic component (10) with respect to the electronic component (10) and plated (20a) on the surface thereof is used as a protruding tip (21) of the lead (20). In the laser welding method of laser welding to the base material (100) at the site on the side)
A first step of applying the plating (20a) to the outer surface of the frame material (23) on a plate-like frame material (23) formed by integrally connecting the lead (20) to the frame (22); ,
A second step of providing the lead (20) on the electronic component (10) in the state of the frame material (23);
After the first and second steps, the lead (20) protruding from the electronic component (10) is formed by cutting and separating the lead (20) from the frame (22). And the process of
Thereafter, a fourth step of performing laser welding of the lead (20) and the base material (100),
As the frame material (23), holes (24, 26) recessed from the outer surface are formed on the outer surface of the frame material (23), and side surfaces extending in the depth direction of the holes (24, 26) are formed. Prepare what is configured as the protruding tip (21) after cutting the lead (20),
In the first step, the plating (20a) is also applied to the side surfaces of the holes (24, 26).   The laser welding method according to claim 1, wherein the hole (24) is a through-hole penetrating the frame material (23).   2. The laser welding method according to claim 1, wherein the hole is a recess (26) that is recessed in a thickness direction of the frame material (23).   The opening shape of the holes (24, 26) has an arc shape having a radius of curvature equivalent to the laser beam diameter during laser welding, and the arc-shaped portion is configured as the protruding tip (21). The laser welding method according to claim 1, wherein the laser welding method is one.

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