Intermixing in immiscible molybdenum/copper multilayered metallization under excimer laser irradiation

The intermixing between Mo and Cu under XeCl laser irradiation was studied. The magnetron sputtered MoCu multilayers were irradiated at fluences up to 1.4 J cm−2 in vacuum and in nitrogen. Analyses were performed using Rutherford backscattering spectrometry and X-ray diffraction (XRD). The intermixing between Mo and Cu layers as well as SiO2 underlayer was suppressed by the presence of reactive gases, namely oxygen incorporated into molybdenum. In accordance with the immiscibility of MoCu pair, only Mo and Cu XRD peaks were observed even after laser melting of copper.