Open AccessFailure mechanism analysis and process improvement on time-dependent dielectric breakdown of Cu/ultra-low-k dielectric based on complementary Raman and FTIR spectroscopy study
Author(s) -
D. D. Wang,
W. L. Wang,
Yanyi Huang,
A. Lek,
Jeffrey Lam,
Z. H.
Publication year - 2014
Publication title -
aip advances
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.421
H-Index - 58
ISSN - 2158-3226
DOI - 10.1063/1.4890960
Subject(s) - time dependent gate oxide breakdown , materials science , dielectric strength , dielectric , low k dielectric , raman spectroscopy , ion , fourier transform infrared spectroscopy , analytical chemistry (journal) , electronic engineering , optoelectronics , gate dielectric , chemical engineering , electrical engineering , chemistry , optics , engineering , physics , organic chemistry , transistor , chromatography , voltage
Time-dependent dielectric breakdown (TDDB) is one of the most important reliability issues in Cu/low-k technology development. With continuous technology scalings to nanometer scales, TDDB issue is further exacerbated. In this paper, two failure mechanisms were investigated: the Ta ions migration model and the line-edge-roughness (LER) model, which is rendering the observed TDDB failure. Complimentary Raman and FTIR spectroscopy was applied to investigate the dielectric bonding characteristics. Our experimental results revealed the TDDB degradation behavior of Cu/ultra-low-k interconnects, suggesting the intrinsic degradation of the ultra-low-k dielectric. No out-diffusion of Cu ions was observed in Cu/Ta/TaN/SiCOH structures. Extensive TEM analysis further verified the migration of Ta ions from the Ta/TaN barrier bi-layer into the ultra-low-k dielectrics. Based on the LER model analysis, a comparative study in both passing and failing die elaborates that the sloped trench/via profile affected the TDDB performance