Correlation between trench depth and TDDB thermal activation energy in single damascene Cu/SiOC: H

In this paper, the thermal acceleration behavior of time dependent dielectric breakdown (TDDB) and its dependence on the trench depth of Cu/SiOC:H single damascene structures are investigated. A decrease in TDDB thermal activation energy with single damascene trench depth is discovered and explained by a non-uniform distribution of thermally activated traps along the SiOC:H low-k trench sidewall. The probable source of the traps is the moisture in the low-k film. Triangular voltage sweep (TVS) was applied to validate the existence of moisture and the moisture content indicated by the hump heights in TVS traces is in good agreement with the TDDB thermal activation energies. Therefore, TDDB thermal acceleration behavior of SiOC:H low-k dielectric could vary with trench depths.