JPS6222447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for assembling a semiconductor device, in which a semiconductor element is fixed to a substrate such as a lead frame using a brazing agent such as solder.

There are two typical conventional assembly methods as follows. The first method is to punch out a tape-shaped solder to the required size and place it on the board on which the semiconductor element will be mounted. The oxide film formed at this time is removed in the next step, and the semiconductor element is placed on the solder from which the oxide film has been removed, and the semiconductor element is rotated left and right several times or reciprocated back and forth. This is a method of welding. The second method is quite similar to the first method, but it does not remove the oxide film of the welded solder that is formed when the solder melts, and instead carries the semiconductor element directly and rotates it left and right several times, or reciprocates. This is a method of welding.

FIGS. 1 and 2 are a sectional view and a partially enlarged view of an assembly apparatus for explaining the conventional typical first and second assembly methods, respectively.

In FIG. 1a, the substrate 1 on which the semiconductor element 9 is mounted is fed in the direction of the arrow. The tape-shaped solder 2 is punched out to a predetermined size using a punch 3 and pressed onto the substrate 1. At this time, the solder 13 punched out to a predetermined size is welded to the substrate 1 by the preheating section 4. However, the solder 13 is not completely melted in this part, but when it is sent to the main heating section 6, the solder 13 is melted and becomes the welded solder 7. When the solder 7 is sent to the main heating section 6, an oxide film 12 is formed on the solder 7 (FIG. 1b).

Next, in order to remove the oxide film 12 formed on the surface of the molten solder 7, the oxide film remover 8 is applied to the top of the molten solder 7, and the oxide film 12 is forcibly removed (Fig. 1c). At step 10, the semiconductor element 9 is placed on the solder 7 from which the oxide film 12 has been removed, and the semiconductor element 9 and the solder 7 are welded by rotating it left and right several times or by moving it back and forth. In the case of FIG. 2, this oxide film remover 8 is not used, and the solder 7 whose surface is coated with an oxide film 12 is shown.
Place the semiconductor element 9 directly on the vacuum chuck 10,
Rotate it left and right several times or go back and forth to weld.

In these methods, in the case of FIG. 1, there is a step of removing the oxide film, and in the case of FIG. 2, the number of rotations and reciprocations increases to remove the oxide film 12, which significantly slows down the work speed. Furthermore, even after the substrate 1 and the tape-shaped solder 2 are welded, they remain on the preheating section 4 and the support stand 30 for a long time, so it is necessary to take measures to prevent the solder 13 from oxidizing. Antioxidant gas such as 11
A major drawback is that the assembly equipment itself becomes complicated, such as passing through the wire.

The present invention provides a method for assembling a semiconductor device that eliminates the above-mentioned drawbacks, shortens the assembly process, and simplifies the assembly equipment. In the assembly method according to the present invention, when a predetermined part of a mounting board that is being fed horizontally on a support stand is positioned on a heating part provided in a part of the support stand, a certain amount of brazing agent made into a wire is applied. A predetermined amount of brazing agent is welded to the heated surface of the predetermined portion, and while the predetermined portion is on the heating portion, time is provided for an oxide film to form on the surface of the welded brazing agent. The method is characterized in that the semiconductor element is lowered onto the welded brazing agent and bonded to the solder.

Next, one embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 3 is a sectional view and a partially enlarged view of an assembly device for explaining one embodiment of the present invention, and is a sectional view and a partially enlarged view of the assembly device.
The same parts as in the figure are given the same numbers. In FIG. 3, the substrate 1 on which the semiconductor element 9 is mounted is fed in the direction of the arrow. When the substrate 1 reaches the main heating section 6 (preheating section unnecessary), the nozzle 20
A wire solder 21 made of Pb (92.5%)-Sn (5%)-Ag (2.5%) and having a diameter of 300μφ is fed diagonally from above by an amount determined to be, for example, 0.5mm. , it is instantaneously welded to the substrate 1 such as a lead frame, and is immediately attached to the vacuum chuck 1.
On top of the solder 7 with the semiconductor element 9 welded at 0.
After about 0.9 seconds, it is sent to the next process where it is cooled and fixed. At this time, the welding temperature is 350° ± 10°C
That's about it.

As described above, according to the method for assembling a semiconductor device according to one embodiment of the present invention, it is possible to easily supply a uniform amount of solder at all times, resulting in excellent electrical characteristics and reliability. Moreover, the structure of the equipment is very simple because the solder is melted and the semiconductor element 9 is welded on one heating section 6, and therefore the manufacturing cost is low. Moreover, after the solder 21 is melted,
The semiconductor element 9 can be welded immediately, and there is no need to worry about forming an oxide film, and there is no need to remove the oxide film, so the assembly process can also be shortened.

The material of the solder and the welding time used in the embodiment of the present invention do not need to be limited to these, and can be optimally selected depending on the semiconductor element 9 and the substrate 1. Further, the material for welding the semiconductor element and the substrate is not limited to solder, and it goes without saying that other brazing materials may be used. The position from which the wired solder is delivered is not limited to diagonally above, but may be from the side, for example.

[Brief explanation of the drawing]

Figures 1 a to d and Figures 2 a to d are cross-sectional views and partially enlarged views of conventional semiconductor device assembly equipment, and Figure 3 a.
-c are a sectional view and a partially enlarged view of a semiconductor device assembly apparatus for explaining an embodiment of the present invention. 1... Board, 2... Tape-shaped solder, 3...
Punch, 4... Preheating section, 5... Gas cover,
6... Main heating section, 7... Welding solder, 8... Oxide film removal tool, 9... Semiconductor element, 10... Vacuum chuck, 11... Cover gas, 12... Oxide film, 13... Solder, 20...nozzle, 21...
...Wire solder, 30...Support stand.

Claims (1)

[Claims] 1. In a method for assembling a semiconductor device in which a semiconductor element is fixed to a predetermined part of a mounting board that is fed horizontally on a support base using a brazing agent, the heating part provided on a part of the support base is When the predetermined portion of the mounting board is sent, a predetermined amount of brazing agent formed into a wire is delivered onto the predetermined portion of the mounting substrate heated by the heating unit, and a predetermined amount of brazing agent is applied to the surface of the predetermined portion. Thereafter, while the predetermined portion of the mounting substrate is on the heating section, and without allowing time for an oxide film to form on the surface of the welded brazing agent, the semiconductor element is attached to the welded soldering agent. 1. A method for assembling a semiconductor device, which comprises adhering the device by lowering the adhesive onto the adhesive.