JPS6233331Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Technical field of the invention This invention relates to the installation of metal cooling bodies (radiating fins) for hermetically sealed semiconductor devices, and has particularly excellent workability.
This article relates to a mounting structure that is effective for heat resistance and strength.

(b) Technical background Generally, semiconductor devices have a maximum allowable temperature from the viewpoint of characteristics or reliability, and silicon semiconductors have a maximum allowable temperature.
75-200°C, and 75-110°C for germanium semiconductors.

The thermal characteristics of a device are generally expressed as a value called thermal resistance. Semiconductor elements for power use or with large current capacity constitute a type of heating element, so they are generally equipped with a heat dissipation structure that reduces thermal resistance to prevent characteristic fluctuations.One example is a method of attaching heat dissipation fins to dissipate heat. be. The thermal resistance from the surface of the device to the air is called the external thermal resistance and is 1/hs (h: thermal conductivity, s:
surface area). If h is regarded as a constant, the larger the total surface area, the more effective the effect.

(c) Prior art and problems Figures 1 and 2 show examples of conventional devices in which heat dissipation fins are attached to hermetically sealed semiconductor devices.

FIG. 1 shows an example in which resin is bonded to ceramic surfaces at both ends, and FIG. 2 shows a conventional example in which resin is bonded directly to metal or ceramic caps.

In the example shown in FIG. 1, a semiconductor element 3 is mounted in a recessed part of a ceramic substrate 2, and a signal line connection pad provided around the element is bonded to a metallized conductor provided on the ceramic substrate 2 via a wire 4. Then, a hermetically sealed semiconductor device 1 is formed by sealing a ceramic or metal cap 5 with gold or tin solder. A heat dissipation fin 6 shown by diagonal lines and having a recessed portion in the center is adhesively fixed to the upper surface of the semiconductor device 1 . The heat dissipation fin 6 is made of aluminum alloy with good thermal conductivity, and is provided with a plurality of protruding pieces 8 to increase the surface area, thereby reducing the weight. Further, the bottom surface of the heat dissipation fin 6 is provided with a recessed portion, and both ends thereof are adhesively fixed with epoxy resin 7 as shown in the figure, with a gap provided between the cap 5 of the semiconductor device 1 and the cap 5 of the semiconductor device 1.

In the example shown in FIG. 2, a heat dissipating fin 6' with a flat bottom surface is directly bonded and fixed to a cap 5 made of metal or ceramic with an epoxy resin 7'.

However, in this bonding method, the epoxy resins 7 and 7' are applied and thermally cured at around 150° C., so the resin layer becomes brittle in environmental tests such as heat stress, and is easily affected by differences in thermal expansion coefficients and deteriorates. In some cases, there is a risk of peeling.

(d) Purpose of the invention In view of the above-mentioned drawbacks, the present invention provides a method of bonding a heat dissipation fin to a metal cap of a semiconductor device with a resin and locking the heat dissipation fin at both ends of the metal cap.
The purpose is to provide a mounting structure that is resistant to heat stress.

(e) Structure of the invention According to the invention, the end of a U-shaped metal cap for sealing a container in which a semiconductor element is housed is inserted into a hole provided in a heat sink, and the end of the cap is inserted into a hole provided in a heat sink. This is achieved by fixing the heat sink to the metal cap by bending.

(f) Examples of the invention Examples of the invention will be described below in detail with reference to drawings.

FIG. 3 is a sectional view showing a semiconductor device to which a heat dissipation fin is attached, which is an embodiment of the present invention.

FIG. 4 is a perspective view of a semiconductor device showing an embodiment of the present invention.

Metal cap 12 of hermetically sealed semiconductor device 11
form into a U shape. The metal cap 12 is sealed to a ceramic substrate 13 with gold-tin solder, and a heat dissipation fin 14 is attached. The radiation fins 14 are inserted into the heat dissipation fins 14 from the upper surface through square holes 14a through which U-shaped protrusions provided at both ends of the metal cap 12 are passed.

As a structure for attaching the heat dissipation fin 14 to the metal cap 12, a U-shaped projection piece 12a is provided on the metal cap 12 in advance and the heat dissipation fin 14 is mounted thereon.
The projection piece 12a is bent to lock the heat radiation fin 14. At this time, resin adhesion can also be used in conjunction with the conventional method.

By using both resin fixing and mechanical fixing methods in this way, the bonding strength is further improved compared to the conventional method.

The metal cap 12 can be made of either an iron alloy or a copper alloy, and the materials used in experiments include 42 alloy and Kovar, and both are effective. It can be used in a wide range of applications as it can have a structure that can sufficiently withstand heat stress.

(g) Effects of the invention As explained in detail above, the heat dissipation fin mounting structure of the invention has an excellent effect on thermal stress that can withstand environmental tests, and has a wide range of applications.
Its practical effects are remarkable.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a conventional example of a heat dissipation fin mounting structure in which resin is bonded to the ceramic surfaces at both ends; Fig. 2 is a sectional view of a conventional example in which heat dissipation fins are mounted in resin bonded to the cap surface of a semiconductor device; The figure is a sectional view showing a semiconductor device to which a heat dissipation fin is attached, which is an embodiment of the present invention, and FIG. 4 is a perspective view of the semiconductor device, which is an embodiment of the present invention. In the figure, 11 is a semiconductor device, 12 is a metal cap, 13 is a ceramic substrate, 14 is a heat radiation fin, and 15 is an adhesive resin.

Claims (1)

[Scope of utility model registration request] An end of a U-shaped metal cap that seals a container in which a semiconductor element is housed is inserted into a hole provided in a heat radiator, and the heat radiator is fixed to the metal cap by bending the end. A semiconductor device characterized by: