| 摘要 |
A method is proposed for bonding a BGA (Ball Grid Array) package to a circuit board without causing the collapsing of the BGA package against the circuit board. The proposed method is characterized in the use of two groups of solder balls of different reflow collapse degrees, which are arranged in an interspersed manner among each other in the ball grid array. In one embodiment, the first group of solder balls are homogenously made of a solder material of a specific melting point; and the second group of solder balls each include an outer portion and a core portion, with the outer portion having substantially the same melting point as the first group of solder balls, and the core portion being greater in melting point than the outer portion. In another embodiment, the second group of solder balls are greater in melting point than the first group of solder balls. During the solder-reflow process, when the first group of solder balls are entirely melted, the second group of solder balls are only partly melted or entirely unmelted and thus are capable of providing a solid support to the BGA package to prevent the collapsing of BGA package against circuit board.
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