An efficient approach to quantify the impact of Cu residue on ELK TDDB

In this study, Triangular Voltage Sweep (TVS) is shown to be an effective way for quantifying the amounts of free Cu ions in porous low-k film. Free Cu ions at the interface that correlate with the Inter-Metal Dielectric (IMD) TDDB lifetime is also discussed. Adding a thermal treatment after the Chemical Mechanical Polish (CMP) process shows that the IMD TDDB lifetime can be improved by at least 2 orders of magnitude with a decrease in Cu ions at the interface. This study also proves that the TVS method can be used to evaluate Cu ions as well as Time-of-Flight Secondary Ion Mass Spectrometry (TOFSIMS).