| 摘要 |
PURPOSE:To efficiently keep the junction temperature of a heat-generating element below its maximum rated operating temperature so as to attain higher density and integrity by a method wherein a low-melting point metal with high thermal conductivity is so arranged as to be in contact with the rear side of a wiring substrate. CONSTITUTION:Several heat-generating semiconductor devices 2 are installed on a wiring substrate 1 and are sealed airtight by means of a metal cap 3 whose thermal expansion factor is roughly equal to that of the wiring substrate 1. A weld link 7 whose thermal expansion factor is roughly equal to that of the wiring substrate 1 is attached securely to the periphery of the rear side of the wiring substrate 1 by means of silver solder 6 or the like and the circumference of a metal dish 8 is attached thereto. The gap between the metal dish 8 and wiring substrate 1 is filled with low- melting point metal 9 that contacts the rear side of the wiring substrate 1 uniformly. When the wiring substrate 1 is exposed to temperatures generated by the semiconductor devices 2 that are higher than the melting point of the low-melting point metal 9, the low-melting point metal 9 absorbs the heat and goes molten so that the temperatures of the wiring substrate 1 and semiconductor devices 2 are lowered to the temperatures near the melting point of the low-melting point metal 9. |
