JPH0454528B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a method of manufacturing a heat sink, and more particularly to a method of manufacturing a heat sink used for fixing a power transistor to be incorporated into a hybrid integrated circuit.

(B) Prior Art As shown in FIG. 3A, the conventional heat sink manufacturing method involves feeding a longitudinal copper plate 11 onto a lower mold 12 in predetermined pitches and pressing it with a press mold 13 to manufacture a heat sink. Was. However, in the above method, the oil 14 adhering to the surface of the copper plate 11 is interposed between the press die 13 and the copper plate 11 during pressing, so in the above manufacturing method, the surface of the heat sink 15 as shown in FIG. 3B is Recess 16
is formed. The surface of the heat sink 15 is the recess 1
6, the heat sink 15 is heated to a high temperature in the process of soldering the chip transistor onto the heat sink 15, and when the solder attached to the heat sink 15 melts, the surface is formed into a concave shape. When the heat sink 15 is in contact with the heat sink 15, the solder moves to the periphery of the heat sink 15 due to surface tension, and there is a problem that the solder does not adhere to the center.

In order to eliminate the above-mentioned drawbacks, we have invented a method of providing a vent hole 17 in the press die 13, as shown in FIG. 4A. According to this, the oil adhering to the copper plate 11 comes out through the ventilation hole 17 during pressing, so the heat sink 18 with a flat surface as shown in FIG.
can be manufactured, and the above-mentioned drawbacks can be solved.

A technique similar to that described above is described in Japanese Patent Application Laid-Open No. 60-216572.

(C) Problems to be Solved by the Invention However, when manufacturing a heat sink using the press mold 13 having the above-mentioned ventilation holes 17, the copper plate 11 is wound around a relay or the like and supplied from there. Naturally, a copper plate 11 that is not warped is not supplied, but a warped copper plate 11 is supplied as shown in FIG. 5A. Then, the tip 21 of the vent hole 17 comes into contact with the copper plate 11 first, and the copper plate 11 is press-fitted into the diameter of the vent hole 7, as shown in FIG. 5B, and the completed heat sink 19 is shown in FIG. 5C. However, the protrusion 20 is formed on the surface, and the protrusion 20 obstructs the attachment of the chip transistor, resulting in the disadvantage that the chip transistor cannot be attached.

(d) Means for solving the problems The present invention has been made in view of the above-mentioned points, and as shown in FIGS. The solution is to do so.

(e) Function By forming the bottom of the press die 4 into a mortar shape and press punching in this way, the tip of the ventilation hole 3 is formed to be recessed inward from the bottom side 5 of the press die 4. Therefore, during pressing, the bottom surface of the press mold 4 comes into contact first, so that a heat sink 6 with a bulging surface is formed.

(F) Embodiments The present invention will be explained in detail below based on the embodiments shown in FIGS. 1A to 1C.

As shown in FIG. 1A, a longitudinal copper plate 1 is placed on a lower mold 2. For example, the copper plate 1 has a width of 13 mm and a thickness of 3
It is wound on a reel etc. to a predetermined length in mm.
From there, it is sent onto the lower mold 2 in predetermined pitches. A warped copper plate 1 is thus provided.

Next, as shown in FIG. 1B, pressing is performed using a press mold 4 having ventilation holes 3. This step is the most characteristic feature of the present invention, and the bottom surface of the press die 4 is formed into a mortar shape. In this case, even if the warped copper plate 1 is supplied, since the bottom of the press mold 4 is mortar-shaped, the vent hole 4 is formed to be recessed from the bottom side 5, and the bottom side 5 is lower during pressing. Since contact occurs first, a heat sink 6 with a raised surface as shown in FIG. 1C can be manufactured. From the values shown in FIG. 2, it is sufficient that the dimensions of the mortar shape satisfy the following conditions: d ₀ ≧t and 5°≦a≦30°.

According to the present invention, by making the bottom of the press mold 4 into a mortar shape, it is possible to form a heat sink 6 that does not have protrusions unlike the conventional one even if a warped copper plate 1 is supplied, and the chip The heat sink 6 that is most suitable for fixing transistors can be mass-produced.

(G) Effects of the Invention As described above, according to the present invention, by making the bottom of the press mold mortar-shaped, manufacturing can be performed without forming protrusions that conventionally occur due to ventilation holes, and chips can be manufactured easily. We can mass-produce heat sinks that are ideal for fixing transistors. Furthermore, if the mortar shape is formed deeper than the warpage of the copper plate, an optimal heat sink can be mass-produced no matter how warped the copper plate is.

[Brief explanation of drawings]

1A to 1C are sectional views showing an embodiment of the present invention, FIG. 2 is a sectional view of the present embodiment, 3A to 3B, and 4A to 4B. 5A to 5C are sectional views showing a conventional example. DESCRIPTION OF SYMBOLS 1...Copper plate, 2...Lower mold, 3...Vent hole, 4...Press mold, 5...Bottom side part, 6...Heat sink.

Claims (1)

[Claims] 1. A method for manufacturing a heat sink on which a semiconductor chip is firmly mounted, the method comprising: press punching a copper plate using a mortar-shaped press mold to form a heat sink with a curved surface.