Integration of Porogen-Based Low-k Films: Influence of Capping Layer Thickness and Long Thermal Anneals on Low-k Damage and Reliability

摘要

This paper discusses integration aspects of a porous low-k film (k～2.45) cured with a broadband UV lamp. Different process splits are discussed which could contribute to avoid integration induced damage and improve reliability. The main factor contributing to a successful integration is the presence of a thick (protecting) cap layer partially remaining after chemical mechanical polishing (CMP), which leads to yielding structures with a κ_(eff) of～2.6, a breakdown voltage of ～6.9MV/cm and time dependent dielectric breakdown (TDDB) lifetimes in the excess of 100 years. Long thermal anneals restore the k-value but degrade lifetime.