Multi-walled Carbon nanotube (MWCNT) has a great tolerance to electromigration (EM). Therefore, MWCNT is expected to be applied to via-material of electronic devices. But, the damage mechanism of MWCNT has not yet been revealed though oxidation by Joule heating and the EM by high density electron flow are proposed as causes of the MWCNT damage under high current density. In this study, we performed acceleration tests of MWCNT to reveal the damage mechanism of MWCNT under high current density. As a result of the acceleration test, lifetime in low vacuum condition with a low oxygen concentration was longer than that in the air. And, local evaporation of carbon due to oxidation appeared near the cathode end of CNT under both conditions. We confirmed presence of two mechanisms of CNT damage; oxidation and EM. It was shown that the oxidation mechanism at the damage site due to EM was enhanced under oxygen rich condition.

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As silicon integrated circuits (ICs) continue to scale down, several reliability issues have emerged. Electromigration — the transportation of metallic atoms by the electron wind — has been recognized as one of the key damage mechanisms in metallic interconnects. It is known that there is the threshold current density of electromigration damage in via-connected line. The evaluation of the threshold current density is one of the great interests from the viewpoint of IC reliability. Recently, the threshold current density in interconnect tree was evaluated. However, it might not be so accurate because of evaluation of two-dimensional structure by combining one-dimensional analysis. In this study, the evaluation method of the threshold current density based on the numerical simulation is applied to several kinds of interconnect tree.