Metal fusion bonding – Solder form
Reexamination Certificate
2005-05-17
2005-05-17
Edmondson, Lynne R. (Department: 1725)
Metal fusion bonding
Solder form
C228S245000, C228S246000, C438S612000
Reexamination Certificate
active
06892925
ABSTRACT:
A lead free solder hierarchy for use in the second level solder connection of electronic components such as joining an electronic module to a circuit board. An off-eutectic solder concentration of SnCu or SnAg is used for the module side connection. This off-eutectic solder contains sufficient intermetallics to provide the module side connection with a robust second level assembly and rework process. The off-eutectic composition provides an inter-metallic phase structure in the module side fillet during assembly. The inter-metallic 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 from the board without simultaneous removal from the module.
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Farooq Mukta G.
Interrante Mario
Sablinski William
Cioffi James J.
Edmondson Lynne R.
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