Comparison of Cobalt Integration with Various Dielectric Materials under Thermal and Electrical Stress
Source abstract
Abstract
Cobalt (Co) is proposed to replace copper (Cu) as a conductor in the back-end-of-line (BEOL) interconnects of integrated circuits. In this study, the electric characteristics and reliability of the integration of Co with various dielectric films (SiO2, dense, and porous low-k SiOCH films) under thermal and electrical stress were compared. Thermal annealing repaired sputtering-Co-deposition-induced damage to the dielectric film but reduced the breakdown field and time-dependence-dielectric-breakdown (TDDB) times due to the diffusion of Co atoms. After annealing, the SiO2 film had the largest reductions in the breakdown field, TDDB failure time, and electric field acceleration factor, indicating that the diffusion of Co atoms dominates in the oxygen-rich surface. Under electrical stress, the drift of Co atoms favors the porous low-k film with the assistance of porosity. As a result, a barrier is required for Co metallization. To achieve barrier-free or barrier-less processing in Co metallization, the dense low-k film is the best option to integrate with Co.
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Research context
OpenAlex topics: Copper Interconnects and Reliability · Semiconductor materials and devices · Electrodeposition and Electroless Coatings
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
Affiliations
Department of Electrical Engineering, National Chi-Nan University, Nan-Tou 54561, Taiwan, R.O.C.
Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan, R.O.C.
Department of Materials Science and Engineering, National Formosa University, Huwei 63201, Taiwan, R.O.C.
Funding
inistry of Science and Technology of the Republic of China, Taiwan
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