Method of bonding solder pads of flip-chip package

Abstract

Disclosed herein is a method of bonding solder pads of a flip-chip package. This invention relates to a method of bonding solder pads having different sizes to each other, when a bonding operation is executed between a chip and a PCB, between chips, or between PCBs. On a side having a larger solder pad, a general solder ball is used. Conversely, on a side having a smaller solder pad, a solder ball having a core is used. The core serves to maintain a predetermined interval between the chip and the PCB or between the chips, after the bonding operation has been completed. The solder bonded parts are aligned with each other so as to perform a final bonding operation. In a conventional flip-chip package, solder pads provided on a bonded part must have the same or similar size. According to this invention, even if the size difference between the solder pads is large, bonding is possible, thus ensuring electrical and mechanical reliability.