Metallurgical System for C4 Joint BLM
Original Publication Date: 1985-Feb-01
Included in the Prior Art Database: 2005-Feb-18
Dissolution of ball limiting metallurgy (BLM) in the solder balls of Pb-In C4 joints on multiple reflows can be prevented by the use of Fe or Fe alloy in the traditional Cr-Cu-Au metallurgy. Wetting of Pb-In solder to Fe provides satisfactory adhesion without degradation on reflowing. An example of the connection structure is shown in the figure.