Heat sink contact layer of solder - providing direct contact between semiconductor substrate and heat sink

Abstract

Abstract The heat sink (1) is a block of copper with a thin e.g. 2000 Angstroms, platinum surface layer (2). A layer (3) of a gold and tin alloy is applied by cathodic sputtering. The ratio between the gold and tin content is 2 to 31. A layer (4) of pure tin is then applied followed by a final layer (5) of gold and tin, similar to the first (3). The sputtering operations are performed at a power of 500 watts at a pressure of between 1 and 10 microbars. The total thickness of the three sputtered layers is about 5 microns. When the layers have been applied, the heat sink is heated to a temp. of 278 deg. C to form a eutectic solder combination.

Inventors

No inventors recorded.

Bibliographic Details