Cu(ReTaN_x) Copper Alloy Films Suitable for Electronic-Device Manufacturing-Process Simplification

摘要

In this study, we prepare Cu(ReTa) and Cu(ReTaN_x) films via reactive cosputtering of copper (Cu), rhenium (Re), and tantalum (Ta) on a barrierless silicon (Si) substrate in an argon-nitrogen (Ar-N_2) atmosphere. These Cu(ReTa) and Cu(ReTaN_x) films, after annealing at 630 and 750℃ for 1 h, exhibit two values of resistivity, viz., 3.05 and 2.35 μΩ cm, respectively, showing high thermal stability without copper-silicide formation. The Cu(ReTaN_x) film's up-to-750℃ high-temperature stability, while maintaining a low leakage current and resistivity, appears to make it a good candidate material for advanced barrierless metallization for simplifying related electronic-device manufacturing processes, and, consequently, reducing the related manufacturing cost. Applying X-ray diffraction (XRD), focused ion-beam microscopy, and transmission electron microscopy (TEM) to evaluate said film, we observed that the Cu seed layer-Si interface showed no detrimental reaction after the film was annealed at 750 ℃ for 1 h. The film, hence, is recommended for the desired purpose.