Optimized structure for organic flip chip package

摘要

We have developed a new type of plastic ball grid array with flip chip inter-connection (P-BGA[FC]) for high-pin counts ASIC and MPU. Conventional P-BGFA[FC] has two main problems, which are large package warp and crack of underfill. The former makes a bad influence on fatigue life of solder ball, and the alter breaks inter-connection and fine wiring in interposer. The new package has an optimized metal lid over Si die to curb the package warp, and uses a brand-new underfill material with great toughness to withstand thermal stress caused by the coefficient of thermal expansion (CTE) mismatch between Si die and organic interposer. The reliability of the new P-BGA[FC] is higher than that of the conventional one.