Effect of the Lattice Mismatch Between Copper Thin-Film Interconnection and Base Material on the Crystallinity of the Interconnection Available to Purchase

In the present study, a new material, ruthenium whose lattice mismatch against copper is about 6%, was used as the seed layer of electroplated copper thin-film interconnections for semiconductor devices. The crystallinity of the copper thin-film interconnections was evaluated through an EBSD (Electron Back-scattered Diffraction) method and it is found that the crystallinity of them is improved drastically compared with those electroplated on the copper seed. The resistance and electro migration (EM) tolerance of the copper interconnections are also improved a lot compared with the interconnections electroplated on copper seed. Based on these results, a new guideline to design highly reliable electroplated copper thin-film interconnection has been established.