Fracture mechanism of LSI conductor due to atom migration induced by electri current and stress

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It is well known that, atoms are transported by thermal stress as well as electric current in an LSI conductor. The interacted migration brings about cavities and the failure of conductor takes place by their growth. The results obtained from this study is summarized as follows. (1) An FEM of diffusion along grain boundaries is developed in order to analyze the cavity growth under the stress-induced migration. The simulation reveals that the diffusion along the interface between the conductor and the insulator strongly affects the atom flow and change the growth rate of cavity. (2) The movement of cavity is analyzed on the basis of atom migration along the surface due to electric current. (3) The analyzing method of cavity growth under interacted migration is discussed on the basis of the results (I) and (2). The method is implanted to the advanced FEM (1), which allows us to analyze the cavity growth in a polycrystalline conductor under the interaction. (4) The cavity grows little under migration induced by only electric current. However, it brings about the stress distribution along the grain boundaries near the cavity and the cavity growth is governed by the atom migration due to the stress gradient.