The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 24, 1997
Filed:
Jan. 18, 1996
Il Kwon Shim, Seoul, KR;
Anam Industrial Co., Ltd., Seoul, KR;
Amkor Electronics, Inc., Chandler, AZ (US);
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.