Electricity: conductors and insulators – Conduits – cables or conductors – Preformed panel circuit arrangement
Patent
1996-01-18
1997-06-24
Thomas, Laura
Electricity: conductors and insulators
Conduits, cables or conductors
Preformed panel circuit arrangement
174260, 361767, 361768, 257738, H05K 102
Patent
active
056419465
ABSTRACT:
Method and circuit board structure for leveling the tops of solder balls of a BGA semiconductor package is disclosed. In order to level the solder balls, the sizes of solder ball lands used for welding the solder balls to the circuit board are controlled in accordance with portions of the circuit board. The invention thus achieves the coplanarity of the solder balls regardless of thermal bending of the plastic body and circuit board of the BGA semiconductor package. In an embodiment, a plurality of solder ball lands having different sizes are formed on the circuit board prior to forming the solder balls on the lands. In another embodiment, a plurality of solder ball lands having the same size are formed on the circuit board prior to forming an insulating mask on the circuit board in order to form differently-sized exposed inside portions of solder ball lands.
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Amkor Electronics, Inc.
Anam Industrial Co., Ltd.
MacDonald Thomas S.
Thomas Laura
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