Chip package interaction (CPI) reliability of Cu/low-k/ultra-low-k interconnect

The introduction of low-k/ultra-low-k (ULK) dielectric materials to accommodate the continuous scaling down of the feature sizes of IC chips to improve the device density and performance of the ultra-large scale integrated (ULSI) circuits represents great silicon and packaging integration challenges due to the weak mechanical properties. To improve CPI reliability of Cu/low-k or ULK devices, a new crackstop design has been introduced. Underfill materials selection, ULK layer effect, interfacial strength improvement of low-k/ULK films, and lead-free impact on chip-package interaction (CPI) reliability are also discussed.