JPH11354549A - Device for supplying solder wire to soldering spot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent molten solder from adhering to the soldering spots of a lead frame, etc., in excess of a required amount without reducing the diameter of a solder wire which is fed to the soldering spots by appropriate lengths, by forming constrictions on the solder wire at the intervals equal to the appropriate lengths. SOLUTION: A solder wire 5 is fed toward a lead frame 1 by appropriate lengths L by intermittently rotating feed rollers 6 and 7. Then constrictions 10 are formed on the solder wire 5 at the intervals equal to the appropriate lengths L by repeating such operations that the wire 5 is clipped with constriction forming punches 8 and 9 by bringing the punches 8 and 9 nearer to each other in an interlocking way of the intermittent rotations of the rollers 6 and 7. Then the rollers 6 and 7 descend toward the frame 1 while holding the wire 5 between them and bring the front end of the wire 5 into contact with the surface of the island section 3 of the frame 1. Consequently, the front end of the wire 5 is melted by the heat of the frame 5 and adheres to the surface of the island section 3 as molten solder 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of soldering a semiconductor chip to a lead frame by soldering, for example, by sequentially soldering a solder wire used for soldering to the soldered portion. It relates to a device for supplying.

[0002]

2. Description of the Related Art Conventionally, when a semiconductor chip is die-bonded to a lead frame by soldering,
After heating the lead frame to a temperature higher than the melting point of the solder, a solder wire is intermittently fed into the lead frame by an appropriate length, and the tip of the solder wire is brought into contact with the pre-heated lead frame. Or, by approaching, the tip is melted by the heat of the lead frame, and at the same time, the molten solder is attached to the lead frame, and then, a semiconductor chip is mounted on the portion where the molten solder is attached, which is adopted. I have.

[0003]

However, in this conventional method, the tip of the solder wire is melted by contacting or approaching a preheated lead frame, and at the same time, the molten solder is applied to the lead frame. By being attached, the amount of molten solder that adheres to the lead frame is proportional to the length at which the tip of the solder wire melts, but the length at which the tip of the solder wire melts depends on the pre-heated lead frame. Is proportional to the temperature.

Accordingly, when the temperature of the lead frame is higher than a predetermined value, the melting length at the tip of the solder wire exceeds the appropriate length when the solder wire is fed in and becomes longer than this. Since the amount of the molten solder adhering to the lead frame becomes unnecessarily large and the excess molten solder overflows or scatters around, the parts which should not be soldered are soldered to each other. Or troubles such as excess molten solder adhering to parts other than the soldering places such as semiconductor chips and lead terminals for the semiconductor chips, etc.
When manufacturing semiconductor components, there is a problem that the occurrence of defective products increases.

[0005] When the temperature of the lead frame is high, in order to prevent the molten solder from excessively adhering, the diameter of the solder wire may be reduced, but if the diameter of the solder wire is reduced, It is necessary to lengthen the feeding length per time in the solder wire,
As a result, the time required for feeding the long length becomes long, which leads to a decrease in work efficiency.

SUMMARY OF THE INVENTION It is a technical object of the present invention to provide a solder wire supply apparatus which solves the above-mentioned problems without lowering the work efficiency.

[0007]

In order to achieve this technical object, the present invention provides a method for intermittently feeding a solder wire by an appropriate length toward a soldering portion such as a pre-heated lead frame. In a solder wire supply device provided with a feeding means, a constricted portion forming means for forming constricted portions on the solder wire at intervals of the appropriate length is provided. "

[0008]

In this configuration, the solder wire fed into the soldering portion such as a lead frame by a suitable length is formed with constricted portions at intervals of the proper length, so that the solder wire can be used. When the tip contacts or approaches a pre-heated soldering point such as a lead frame, the heat transmitted in the longitudinal direction of the solder wire becomes difficult to transmit in the constricted portion provided on the solder wire, Since the molten solder is easily separated from the solder wire at the constricted portion, when the temperature of the soldering portion such as the lead frame is high, it is ensured that the tip of the solder wire is melted beyond the constricted portion. In other words, the melting of the tip of the solder wire beyond the appropriate length can be reliably reduced. A.

Therefore, according to the present invention, when a solder wire is fed into a soldering location, it is possible to reliably reduce the unnecessary adhesion of the molten solder to the soldering location without reducing the diameter of the solder wire. From this point of view, work efficiency can be improved by causing problems such as soldering parts that should not be soldered due to excess molten solder or attaching excess molten solder to parts other than the soldering location. It is possible to significantly reduce the occurrence of a defective product without causing a decrease in the quality of the semiconductor component.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this figure,
Reference numeral 1 denotes a lead frame made of a thin metal plate. In this lead frame 1, an island portion 3 for mounting a semiconductor chip 2 and a plurality of lead terminals 4 are arranged at appropriate intervals along the longitudinal direction. It is formed with.

Reference numeral 5 denotes a solder wire supplied downward toward the upper surface of the island portion 3 of the lead frame 1. The solder wire 5 is supplied to a pair of left and right feed rollers as one of the feeding means. 6 and 7, and in this state, the feed wires 6 and 7 are intermittently rotated by an appropriate angle so that the solder wire 5 is appropriately extended toward the island portion 3 of the lead frame 1. The feed is performed intermittently by L.

A pair of right and left punches 8 and 9 which are one of the constricted portion forming means are provided between the feed rollers 6 and 7 and the lead frame 1. That is, when the two punches 8 and 9 complete the feeding of the solder wire 5 toward the lead frame 1 by an appropriate length L by the intermittent rotation of the two feeding rollers 6 and 7, the punches 8 and 9 move closer to each other, and move toward the solder. By repeatedly interposing the wire 5 between the left and right sides thereof in conjunction with the intermittent rotation of the feed rollers 6 and 7, the solder wire 5
In addition, the constricted portions 10 are formed at intervals of the appropriate length L.

In this configuration, the two feed rollers 6,
When the feeding of the solder wire 5 toward the lead frame 1 by an appropriate length L by the intermittent rotation of the wire 7 is completed, the feed rollers 6, 7 are lowered toward the lead frame 1 with the solder wire 5 interposed therebetween. By moving, the tip of the solder wire 5 is connected to the lead frame 1.
Contact or approach the upper surface of the island portion 3 at

As a result, the tip of the solder wire 5 is melted by the heat of the lead frame 1, so that the molten solder 11 can be attached to the upper surface of the island portion 3 in the lead frame 1. In this case, the constricted portion 10 is formed on the solder wire 5 by the appropriate length L.
When the tip of the solder wire 5 contacts or approaches the preheated island portion 3 of the lead frame 1, the heat transmitted in the longitudinal direction of the solder wire 5 is: When the temperature of the lead frame 1 is high, when the temperature of the lead frame 1 is high, the solder is hardly transmitted at the constricted portion 10 provided on the solder wire 5 and the molten solder is easily separated from the solder wire 5 at the constricted portion 10. The tip of the wire 5
Melting beyond the constricted portion 10 can be reliably reduced, in other words, the melting of the solder wire 5 beyond the appropriate length L beyond the appropriate length L can be reliably reduced. .

When the molten solder 11 adheres to the upper surface of the island portion 3 as described above, the lead frame 1 moves the island portion 3 to another location and mounts the semiconductor chip 2 on the upper surface. Then, die bonding is performed by soldering the semiconductor chip 2 by cooling. Further, in the above-described embodiment, the feeding means for the solder wire 5 and the constricted portion forming means for the solder wire 5 have different configurations. However, the present invention is not limited to this, and as shown in FIG. In addition, a projection 8 ', 9' for forming a constricted portion is provided on the outer peripheral surface of a pair of feed rollers 6 ', 7', and a constricted portion 10 is formed on the solder wire 5 while feeding it. Alternatively, the feeding means and the constricted portion forming means may be configured as one structure.

Furthermore, in the above embodiment, the case where the semiconductor chip 2 is applied to die bonding by soldering to the lead frame 1 has been described. However, the present invention is not limited to this, and another solder It is needless to say that the present invention can be applied to the attaching portion, and it is needless to say that the present invention can also be applied to a case where the solder wire is fed laterally to the soldering portion.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional front view showing a main part of FIG. 1;

FIG. 3 is a longitudinal sectional front view showing another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lead frame 2 Semiconductor chip 3 Island part 4 Lead terminal 5 Solder wire 6,7,6 ', 7' Feeding roller 8,9 Punch for forming a constriction 8 ', 9' Protrusion for forming a constriction 10 Constriction

Claims (1)

[Claims] 1. A solder wire supplying apparatus comprising: a feeding means for intermittently feeding a solder wire by a suitable length intermittently toward a pre-heated soldering portion such as a lead frame. A device for supplying a solder wire to a soldering portion, wherein a constricted portion forming means for forming a constricted deformation portion at an interval of an appropriate length is provided.