Package characterization on advanced NBA-QFN structure
In recent years, electronic product have been demanded more functionalities, miniaturization, higher performance, reliability and low cost. Therefore, IC chip is required to deliver more signal I/O and better electrical characteristics under the same package footprint. None-Lead Bump Array (NBA) Chip Scale Structure is then developed to meet those requirements offering better electrical performance, more I/O accommodation and high transmission speed. To evaluate NBA package capability, the solder joint life, package warpage, die corner stress and thermal performance are characterized. Firstly, investigations on the warpage, die corner stress and thermal performance of NBA-QFN structure are performed by the use of Finite Element Method (FEM). Secondly, experiments are conducted for the solder joint reliability performance with different solder coverage and standoff height In the conclusion of this study, NBA-QFN would have no warpage risk, lower die corner stress and better thermal performance than TFBGA from simulation result. Beside that, the simulation result shows good agreement with experimental data. From the drop test study, with solder coverage less than 50% and standoff height lower than 40um would perform better solder joint life than others.