| 摘要 |
<p>PURPOSE:To pevent the change of the pitches of fins by thickening the thickness of fin-root sections engaging with a thermal conductor and thinning other sections with regard to the thickness of a heat sink. CONSTITUTION:A semiconductor chip 1 is bonded on a wiring substrate 2 by soldering balls 3. The wiring substrate 2 is supported by a lower casing 5, and a heat sink 6 finctioning as an upper casing in combination is mounted from the upper section of the lower casing 5. Plate-shaped fins 7 are formed to the heat sink 6, and a thermal condutor 10 with fins 9 mutually engaging with the fins 7 at intervals 8 is pushed against the chip 1 by a spring 11. When the fins 7 are formed to the heat sink 6, the depth of bottoms among fins 7 in sections engaging woth the thermal conductor 10 is made shallower than the depth of sections not concerned in engagment, and the thickness of the heat sink 6 in the sections is thickened.</p> |
