Reliability Research on micro bump and c4bump in Large-Size 2.5D FCBGA

The electronic components using flip chip bonding technology have high pin density, good thermal conductivity and excellent electrical performance, and are widely used in the telecommunications field. In this paper, -5000m$\mathrm{m}^{2}$ area 2. 5D FCBGA is taken as the research object, and the failure phenomenon of its key interconnect structure under temperature cycle is tested and simulated. In the test, it was found that ubump failed earlier than c4bump, and there were underfill delamination on both sides of the copper pillar with different bump structures. Then, the impact of underfill delamination on the stress of the bump is studied through finite element analysis, and the failure risks of the two kinds of bump structures are compared. Finally, it is proposed that proper underfill materials can reduce the failure risk of bump.