A plastic package (10) with a heat sink (11, 27, 28, 32) has a stress relief wall (18, 21, 33) formed on its upper surface. A semiconductor die (12) is mounted on the heat sink (11, 27, 28, 32) such that the top of a semiconductor die (12) is below the level of the top of the wall (18, 21, 33), and the...http://www.google.de/patents/US5278446?utm_source=gb-gplus-sharePatent US5278446 - Reduced stress plastic package
