SEMICONDUCTOR DEVICE ATTACHED ON A SUBSTRATE

摘要

A semiconductor chip 4 is attached to a ground plane layer 2 on a substrate 1 by a face down method through solder balls 7. A heat transfer material 5 attached to the ground plane layer 2 is in thermal contact with the semiconductor chip through a flexible heat transfer layer 9. The heat from the semiconductor chip is radiated by a large area by using the ground plane layer. The semiconductor chip and the heat transfer material are in contact with each other in a relatively movable state, to prevent that the thermal stresses from the substrate being exerted on the semiconductor chip.