Electronic assembly with optimum heat dissipation

Claim 1

An electronic assembly comprising in order: (a) a semiconductor chip having a surface area A C , (b) a metal heat spreading layer having a first edge and a second edge, said heat spreading layer having a thickness T and a surface area A M , where A M >A C , (c) a layer of an electrically insulating dielectric material having a surface area A D , where A D >A M , and (d) a metal heat sink layer having a surface area A S , where A S >A D , wherein said chip is located at a distance D 1 from the first edge of the metal heat spreading layer and a distance D 2 from the second edge of the metal heat spreading layer and angles φ 1 , φ 2 and φ ave are defined by the relationships ##EQU2## wherein angle φ is the angle inscribed by (1) a line from an edge of the chip to the edge of an upper surface of the heat spreading layer, which is parallel to a surface of the heat spreading layer, and (2) a line connecting an edge of the chip to an edge of a lower surface of the heat spreading layer, angle φ 1 is the angle using the smallest distance, D 1 and angle φ 2 is the angle using the largest distance D 2 and further wherein one of the following dimensional relationships exists: (1) T=5-9 mils and φave=2° to 3°, (2) 9>T>15 mils and φave=4° to 9°, or (3) T=15-20 mils and φave=7 to 8°.