公开(公告)号：EP1545826A4

公开(公告)日：2009-02-11

申请号：EP03755830

申请日：2003-09-12

Applicant: IBM

Inventor： INTERRANTE MARIO ,  FARCOOQ MUKTA G ,  SABLINSKI WILLIAM EDWARD

IPC: B23K1/00 ,  B23K31/02 ,  B23K35/12 ,  B23K35/14 ,  B23K35/26 ,  B23K35/34 ,  B23K101/40 ,  B23K101/42 ,  C22C13/00 ,  H05K3/34

CPC classification number: B23K1/0016 ,  B23K35/262 ,  B23K2201/36 ,  H01L2224/16225 ,  H05K3/3436 ,  H05K3/3463 ,  H05K2201/10992 ,  H05K2203/041 ,  H05K2203/0415 ,  Y02P70/613

Abstract: A lead free solder hierarchy for use in the second level solder connection of electronic components such as joining an electronic module (20) to a circuit board (120). An off-eutectic solder (60) concentration of SnCu or SnAg is used for the module side connection. This off-eutectic solder (60) contains sufficient intermetallics to provide the module side connection with a robust second level assembly and rework process. The off-eutectic composition (60) provides an inter­metallic phase structure in the module side fillet during assembly. The inter­metallic phase structure eliminates problems of tilt and collapse during second level assembly and aids in rework by providing a more cohesive joint allowing removal of the columns (100) from the board (120) without simultaneous removal from the module (20).