abstract |
An integrated circuit component is attached to a printed circuit board by solder bump interconnections that are formed between metal bumps on the component and a metal-plated terminal on the board. The metal plate overlies both a bond pad and an adjacent runner of each terminal and is formed of a first metal, which is preferably a tin-base alloy. The metal bumps on the component are formed of a second metal, which is preferably an indium-base alloy. The component and board are assembled and heated to a temperature less than the melting temperatures of the first and second metals. At the interface between the bumps and the plate, the first and second metals cooperate to form a liquid phase which, upon cooling and solidifying, completes the interconnection. |