Dielectric Reliability of 50 nm Half Pitch Structures in Aurora® LK

摘要

The dielectric reliability of Aurora® LK (k = 3.0) material has been evaluated on a 50 nm half pitch test structure. These were fabricated using a double patterning scheme and TiN metal hard mask. The introduction of a suitable post-etch residue removal step and close-coupled processing between Cu electroplating and chemical mechanical polishing were found to be key for achieving high yield. Median time-dependent dielectric lifetime of 10 years is reached at an electrical field of 1.4 MV/cm, comparable to earlier reported results with SiO_2 as dielectric. The reliability performance is found to be significantly layout dependent with corners being weak points due to local field enhancement.