Characterization of Ru–Mn composites for ULSI interconnects

• Published in: Microelectronic engineering 2013-12, Vol.112, p.103-109
• Main Authors: Wojcik, H., Krien, C., Merkel, U., Bartha, J.W., Knaut, M., Geidel, M., Adolphi, B., Neumann, V., Wenzel, C., Bendlin, M., Richter, K., Makarov, D.
• Format: Article
• Language: English
• Subjects: Annealing; Applied sciences; Barriers; Bias temperature stress; Copper; Cross-disciplinary physics: materials science; rheology; Cu diffusion barrier; Design. Technologies. Operation analysis. Testing; Diffusion barriers; Direct Cu plating; Electrical engineering. Electrical power engineering; Electronics; Exact sciences and technology; Heat treatment; Integrated circuits; Manganese; Materials; Materials science; Metals. Metallurgy; Methods of deposition of films and coatings; film growth and epitaxy; Physical vapor deposition; Physics; Plating; Production techniques; Ruthenium composite; Ru–Mn; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Vapor phase epitaxy; growth from vapor phase; X-ray photoelectron spectroscopy
• ISSN: 0167-9317; 1873-5568
• DOI: 10.1016/j.mee.2013.02.057

Graphical abstract In this study, PVD Ru–Mn composites were investigated in terms of major concerns that arise with the introduction of a new type of barrier. First, the Cu diffusion barrier performance after annealing at 600°C and under subsequent BTS of +2MV/cm, 250°C was investigated on SiO2, and after 350°C annealing on low-k dielectrics. Ru–Mn films proved to serve as outstanding Cu diffusion barrier over a wide range of Mn content. Second, the origin of the barrier performance was investigated using TEM, EELS and XPS depth profiling techniques, revealing the stuffing of grain boundaries as barrier mechanism. Third, Cu plating on damascene wafers applying a Ru–Mn seed layer was tested, and also the Cu adhesion thereon, resulting in a complete feature fill and excellent Cu wetting behavior. Fourth, the blocking of oxygen diffusion was examined, leading to a performance comparable to PVD TaN. Finally, the Mn content inside Ru was reduced down to 1at.% without compromising the superior material properties.