High reliable FC-PBGA

This paper is concerned with the high reliability of FC-PBGA (Flip Chip-Plastic Ball Grid Array). While flip chip technology is experienced in watch assembly and has a cost advantage, the chip sizes for watches are too small and not directly applicable to high reliable FC-PBGA. Considering the application of FC technology to FC-PBGA, the bump structure change for lower stress will be effective. For this change, three steps have been under examination: (1) application of FC assembly to peripheral bump structure, (2) establishment of re-distribution structure on chip, and (3) application of FC technology to area array bump structure. The result of the first step, application of FC assembly to peripheral bumping is reported in this paper. The bump structure has ensured a thermal fatigue resistance 3,000 cycles under the condition -40 C 30 min/125 C 30 min.