JPH0711472Y2 - Semiconductor device - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a semiconductor device, particularly a semiconductor device suitable for rectifying the output of an automobile generator.

[0002]

2. Description of the Related Art As shown in FIG. 8, a conventional rectifier (1) used in an automobile generator has a plurality of individual completed rectifier diodes (2) soldered (3) to a radiator (4). )
It has a structure fixed to the. A variety of shapes and sizes of radiators (4) are selected and used according to the difference in current capacity and mounting structure to automobiles. The rectifier diode (2) has a diode chip (not shown) bonded between the metal container (6) and the lead electrode (7) with solder,
These diode chips are sealed with a sealing resin (5) which is filled and hardened in a metal container (6).

[0003]

[Problems to be Solved by the Invention] In the manufacturing process of a rectifying device (1), soldering work is performed in which a rectifying diode (2) is bonded to a radiator (4) by solder (3). At that time, since the rectifier diode (2) is heated together with the radiator (4) to a temperature of 200 ° C. or higher, which exceeds the allowable storage temperature 150 ° C., the characteristics of the rectifier diode (2) may be deteriorated.

When the above-mentioned soldering is performed by an electric equipment manufacturer, it is general that after the soldering, a powder coating process or the like is performed, and then the quality inspection of the rectifying device (1) is performed. Therefore, there is a waste of powder coating or the like on the defective rectifying device (1) including the defective rectifying diode (2) whose characteristics are deteriorated by the soldering work.

On the other hand, semiconductor device manufacturers aim to manufacture and deliver products that do not become defective at the shipping destination. If the rectifier diode (2) fails in the electrical equipment manufacturer, there is a risk that the semiconductor device manufacturer will be held responsible for whatever reason. Therefore, in many cases, a semiconductor device manufacturer takes charge of soldering work of the rectifier diode (2) and removes defective products due to soldering, and delivers the rectifier device (1) to the electrical equipment manufacturer. .

However, when the semiconductor device manufacturer solders the rectifying diode (2), as described above,
Since the radiator has various sizes and shapes, the rectifier (1) is produced in a small quantity and in various types, and the productivity is reduced. Also, both semiconductor device manufacturers and electrical equipment manufacturers have the inconvenience of having to deal with a radiator (4) that is much larger than the rectifier diode (2).

[0007] Therefore, an object of the present invention is to provide a semiconductor device such as an electric component manufacturer that does not cause a defect at the delivery destination of the semiconductor device and has high productivity.

[0008]

The semiconductor device of the present invention comprises:
A metal heat dissipation board and a semiconductor element body having a semiconductor element mounted on one main surface of the heat dissipation board, and a metal external heat dissipation body fixed to the semiconductor element body are provided. The concavo-convex coupling surface formed on the other main surface of the heat dissipation substrate is pressed against the concavo-convex coupling surface formed on the external heat radiator in a fitted state via a thin film having good thermal conductivity.

[0009]

The semiconductor element body can be mass-produced, and a semiconductor device having excellent heat dissipation can be constructed by appropriately combining it with external heat radiators of various sizes and shapes. Furthermore, since a thin film having good thermal conductivity is interposed between the coupling surface of the heat radiation substrate and the coupling surface of the external heat radiator, the both are fitted together, so that the thermal conductivity from the heat radiation substrate to the external heat radiator is improved. .

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention applied to an automobile rectifier will be described below with reference to FIGS.

As shown in FIG. 1, the semiconductor device (11) of the present invention comprises a semiconductor element body (12) and an external heat radiator (13) fixed to the semiconductor element body (12). The semiconductor element body (12) includes three rectifying diodes (14) and a heat dissipation board (15).
Have and.

Each of the rectifying diodes (14) has a diode chip (17) bonded by solder (16) on one main surface (15a) of the heat dissipation board (15). The lead electrode (19) is bonded to the upper surface of the diode chip (17) through the solder (18). The entire diode chip (17) and one end of the lead electrode (19) are covered with a protective resin (20) made of silicone resin. Protective resin (20)
One end of the lead electrode (19) is covered with a sealing resin (21) made of epoxy resin. As shown in FIGS. 2 and 3, the other end of the lead electrode (19) is covered with a sealing resin (2
It is derived from 1).

The heat dissipating board (15) is made of a metal having excellent heat dissipation.
It consists, for example, of copper coated with nickel. Heat dissipation board (15)
The other main surface (15b) has a concavo-convex coupling surface (15c). One main surface (13a) of the external heat radiator (13) has an uneven coupling surface (13b) that engages with the uneven coupling surface (15c) of the heat dissipation board (15).

The concavo-convex coupling surface (15c) of the heat dissipation substrate (15) has a saw-toothed cross section, and the concave portion forms a large number of V grooves running in parallel. Through holes (24) for inserting the mounting screws (23) are provided at both ends of the radiator plate (15). The external heat radiator (13) is made of a metal having a good heat radiation property such as aluminum. The concavo-convex coupling surface (13b) of the external heat radiator (13) has a complementary sawtooth cross section so as to engage with the concavo-convex coupling surface (15c) of the heat dissipation board (15), and the concave portions thereof are parallel to each other. V running to
Form a groove. A mounting screw hole (25) is provided on the one main surface (13a). On the other main surface (13c) of the external radiator (13), there are radiating fins (26) for promoting heat radiation.
Is provided. As shown in a partially enlarged view in FIG. 5, a thin film (28) having good thermal conductivity, such as an aluminum foil, is arranged between the concave and convex coupling surfaces (13b) and (15c). Semiconductor element body (1
2) is attached to the external heat radiator (13) with a mounting screw (23) via a washer (27). When the mounting screw (23) is tightened, the uneven connection surface (15c) of the heat dissipation board (15) is pressed against the uneven connection surface (13b) of the external heat radiator (13), and strongly adheres to each other in a fitted state. Since they are coupled, the other main surface (15b) of the heat dissipation board (15) and one main surface (13a) of the external radiator (13) have good heat transfer through the thin film (28) having good heat conductivity. Form a joint. In this case, if the tip of each convex portion of the concavo-convex joint surface (13b) and (15c) is slightly cut at a constant height, the concavo-convex joint surface (13b) and (15c) can be adhered evenly. Good.

For example, the diode chip 1 of the semiconductor device (11) used in the rectifier circuit of the automotive alternator shown in FIG.
7 rectifies the three-phase alternating current obtained from the automotive alternator at the parallel connection parts (a) and (b) indicated by the broken line.

In the present invention, since the semiconductor element body (12) can be attached to the external heat radiating body (13) without the need for soldering as in the conventional case, the semiconductor device maker is required to attach the above-mentioned attachment to the electrical equipment maker. It became possible to entrust to. As a result, in this embodiment, the semiconductor device body (12) can be manufactured by the semiconductor device manufacturer and delivered to the electrical equipment manufacturer. The electrical equipment manufacturer prepares external radiators (13) having various sizes and shapes according to the type of automobile,
Assemble the semiconductor device (11) by screwing.

A semiconductor device (11) completed through the above steps
Was found to have no problem in heat dissipation characteristics and to improve productivity. In particular, since the rectifying diode (14) is not soldered after the resin sealing, the characteristic deterioration of the rectifying diode due to the soldering, which has been a conventional problem, does not occur at all.

Further, in the conventional rectifier (1), the sealing resin (5) of the rectifier diode (2) is heated by soldering when fixing the rectifier diode (2) to the radiator (4), There is a risk that cracks may occur or peeling may occur between the metal container (6) or the lead electrode (7) and the sealing resin (5). Therefore, a hard resin cannot be used as the sealing resin (5), and only a soft resin is used. However, the soft resin is far inferior to the hard resin in the ability to prevent invasion of harmful substances from the outside. In the first embodiment of the present invention, since the rectifying diode is not fixed to the adherend by soldering after the resin sealing, hard resin can be used as the sealing resin (21), and the degree of freedom in selecting the material of the sealing resin is high. Since it is improved, it becomes possible to improve the environmental resistance performance.

Next, FIG. 7 showing a second embodiment of the present invention will be described. In FIG. 7, the same parts as those shown in FIGS. 1 and 8 are designated by the same reference numerals, and the description thereof will be omitted.
The rectifier (31) of the second embodiment is a rectifier diode (2).
A semiconductor element body (32) composed of a heat dissipation board (15) is attached to an external heat dissipation body (13). Three rectifying diodes (2) are bonded to the upper surface of the heat dissipation board (15) via solder (3). The rectifier diode (2) is shown in Fig. 8.
The same as that of FIG. 1 and the coupling structure of the heat dissipation board (15) and the external heat dissipation body (13) is the same as that of FIG. In the second embodiment, the effect of preventing characteristic deterioration due to soldering is not very high, but the effect of preventing failure in the post-process or electrical equipment manufacturers and the advantage of being able to use external heat radiators of different shapes or sizes are exhibited. .

The above embodiment of the present invention can be variously modified. For example, the semiconductor device of the present invention including three rectifying diodes is shown in FIG. 4, and the parallel connection part (a) of FIG.
It is also possible to implement the present invention in a semiconductor device including two rectifying diodes, each of which is one rectifying diode (b). When an aluminum material is used as the heat dissipation substrate (15) instead of nickel-coated copper, soldering is required for the fixed portion of the rectifier diode, so a nickel layer may be formed on the aluminum material. This nickel layer can be formed by nickel plating via a zinc displacement plating layer or by pressure bonding the nickel layer. The heat dissipation board (15) is best attached by screws, but it can also be attached by rivets.

The effects of this embodiment are as follows.

(1) The productivity of the rectifier can be improved.
That is, in the semiconductor device of the present invention, by mounting the semiconductor element body on an external heat radiator having a different shape and size without changing the size or shape of the semiconductor element body, it is possible to widely meet various requirements depending on the current capacity or the mounting structure. it can. The electrical equipment manufacturer can attach the semiconductor element body to the external heat radiator without the need for the above-mentioned soldering work. Therefore, as a semiconductor device manufacturer, it is possible to shift the production system of the rectifier from the small-quantity multi-product production to the large-volume production, and improve the productivity. Since the heat dissipation board is smaller than the external heat dissipation body, there is an advantage of improving productivity in that semiconductor device manufacturers can handle small semiconductor element bodies. In addition, in the case of electrical equipment manufacturers, since a production system adapted to a wide variety of automobiles is adopted and articles larger than those of semiconductor device manufacturers are handled, the productivity does not substantially decrease even if the external heat radiator is handled.

(2) The semiconductor device maker can assemble the semiconductor element body, and after the product inspection, can deliver only non-defective products to the electrical component manufacturer without any defect at the shipping destination.

(3) After the product inspection, the products delivered from the semiconductor device manufacturer are subjected to powder coating and other processing, so reduction of wasteful processes at the electrical equipment manufacturer that performs powder coating and other processing on defective products Is possible.

(4) Since the heat dissipation substrate of the present invention is smaller and has a smaller heat capacity than the conventional heat dissipation device, the time required to reach a predetermined soldering temperature and the time required to cool from the soldering temperature to a certain temperature are shortened. Therefore, in the present invention, even if the soldering time is the same as the conventional one, the high temperature holding time of the rectifier diode can be shortened, and therefore the characteristic deterioration of the rectifier diode is less likely to occur. It is possible to reduce the occurrence of defective diodes in soldering for bonding the rectifier diode to the adherend.

[0026]

As described above, according to the present invention, the concavo-convex coupling surface of the heat dissipation board is pressed against the concavo-convex coupling surface of the external heat radiator in a fitted state via the thin film having good thermal conductivity. So
A semiconductor device having excellent heat dissipation can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded sectional view taken along the line II of FIG. 2 showing a first embodiment of a semiconductor device according to the present invention.

FIG. 2 is a perspective view of a semiconductor device.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a circuit diagram in which a semiconductor device according to the present invention is connected.

FIG. 5 is an exploded sectional view when a thin film is inserted between a heat dissipation board and an external heat dissipation body.

6 is a cross-sectional view after assembly of FIG.

FIG. 7 is a perspective view of a semiconductor device showing a second embodiment of the present invention.

FIG. 8 is a perspective view of a conventional semiconductor device.

[Explanation of symbols] (2), (14). ． Rectifier diode, (11), (3
1). ． Semiconductor device, (12), (32). ． Semiconductor device body, (13). ． External radiator, (13a). ． One main surface, (13b). ． Concavo-convex coupling surface, (15). ． Heat dissipation board, (15a). ． One major surface, (15b). ． The other major surface, (15c). ． Concavo-convex joint surface, (17). ． Diode chip (semiconductor element), (21). ． Sealing resin, (2
8). ． Thin film,

Claims (4)

[Scope of utility model registration request] 1. A semiconductor element body having a metal heat dissipation board and a semiconductor element mounted on one main surface of the heat dissipation board, and a metal external heat dissipation body fixed to the semiconductor element body. The concavo-convex coupling surface formed on the other main surface of the heat dissipation substrate is pressed against the concavo-convex coupling surface formed on the external heat radiator in a fitted state via a thin film having good thermal conductivity. A semiconductor device characterized by the above. 2. The semiconductor device according to claim 1, wherein a coupling surface of the unevenness of the heat dissipation substrate and the external heat dissipation body is formed as a tapered unevenness. 3. The semiconductor device according to claim 1, wherein the other main surface of the external heat radiator has a large number of heat radiation fins. 4. The semiconductor device according to claim 1, wherein the semiconductor element is an individual rectifying diode bonded to the heat dissipation board.