CAVITY GROWTH INDUCED BY ELECTRIC CURRENT AND STRESS IN LSI CONDUCTOR

摘要

Numerical simulations are conducted for the cavity growth in the polycrystalline LSI conductor under the electromigration and the stress induced by the electric current, and the mechanism and the mechanics arc analyzed. No external load is applied in the simulation, so that the stress is caused by the electromigration and the mass conservation. The results obtained are summarized as follows. (1) The matrix equation is derived for the atom transport caused by the electric current as well as the stress in a polycrystalline material. The atom flux along the GB (IF) near a cavity in an LSI conductor with arbitrary GB/IF network can be numerically analyzed by the equation. (2) The high stress concentration is induced by the combined migration at the junction of GB and IF in the conductor without a cavity. When a cavity is introduced at the junction, the atom flow is activated in the vicinity of it. As the cavity grows, the activated region expands. The cavity grows under the electric current. (3) The efflux at the cavity tip is governed by the induced stress while the flow-out atoms are carried away by the elecromigration. (4) The cavity growth rate is dependent not only on the combined diffusivity, DjdilDhdin and cavity size but also on the GB/IF network. This investigation was supported by the Grant-in-aids for scientific research; B(2) No.11555031 and No.00114433.