多結晶材料における結晶粒界品質と強度の相関性評価

抄録

The use condition of polycrystalline materials including metals has become severe as represented by the increase in the current density on the semiconductor interconnection due to its miniaturization. Thus, various degradation phenomena such as local Joule heating and electromigration (EM) have become apparent and it's becoming difficult to guarantee long-term reliability of products. Recently, it was found that the quality of a grain boundary varies drastically depending on the manufacturing process of the thin-film interconnections and EM generates voids and hillocks around grain boundaries especially random grain boundaries in the interconnection. So it is necessary to evaluate the aging degradation of the interconnection material quantitatively. In this study, by using a copper thin film as a sample material of the interconnection, grain boundary strength was evaluated quantitatively by applying micro tensile test method and grain boundary quality was measured as analysis parameter IQ (Image Quality) value, which indicates atomic arrangement calculated by the sharpness of Kikuchi lines obtained by EBSD (electron backscatter diffraction) method. As a result, it was found that a strong correlation between strength and IQ value, that grain boundary strength monotonically increases with increasing of IQ value by increasing number of atomic bonds due to fewer atomic defects. On the other hand, the transgranular strength monotonically decreases by easier dislocation movement due to improving order of atomic arrangement.