Comparative analysis and study of ionized metal plasma (IMP)-Cu and chemical vapor deposition (CVD)-Cu on diffusion barrier properties of IMP-TaN on SiO₂

Comparative study of ionized metal plasma (IMP)-Cu and chemical vapor deposition (CVD)-Cu on diffusion barrier properties of IMP-Tantalum nitride (TaN) has been investigated in the Cu(200 nm)/TaN(30 nm)/SiO₂(250 nm)/Si multi-layer structure. IMP-TaN thin film shows a better metallurgical and thermal stability with IMP-Cu than CVD-Cu thin film not due to lower concentration of oxygen and carbon in Cu film, but due to the smaller grain size and lower roughness of IMP-Cu microstructure. The thermal stability was evaluated by electrical measurements, X-ray diffraction (XRD) and RBS. As a main part of the studies, the atomic intermixing, new compound formation, and phase transitions in the test structure were also studied. For the comparison of IMP and CVD deposited Cu and their effect on the IMP-TaN diffusion barrier, atomic force microscopy (AFM), SIMS, XRD and Rutherford backscattering spectroscopy (RBS) were employed in conjunction with electrical measurements.