电沉积Mo和Mo-Co合金纳米线用于互联电阻的电阻率改性

Achieving historically anticipated improvement in the performance of integrated circuits is challenging,due to the increasing cost and complexity of the required technologies with each new generation.To overcome this limitation,the exploration and development of novel interconnect materials and processes are highly desirable in the microelectronics field.Molybdenum(Mo)is attracting attention as an advanced interconnect material due to its small resistivity size effect and high cohesive energy;however,effective processing methods for such materials have not been widely investigated.Here,we investigate the electrochemical behavior of ions in the confined nanopores that affect the electrical properties and microstructures of nanoscale Mo and Mo-Co alloys prepared via template-assisted electrodeposition.Additives in an electrolyte allow the deposition of extremely pure metal materials,due to their interac-tion with metal ions and nanopores.In this study,boric acid and tetrabutylammonium bisulfate(TBA)were added to an acetate bath to inhibit the hydrogen evolution reaction.TBA accelerated the reduction of Mo at the surface by inducing surface conduction on the nanopores.Metallic Mo nanowires with a 130 nm diameter synthesized through high-aspect-ratio nanopore engineering exhibited a resistivity of(63.0±17.9)μΩcm.We also evaluated the resistivities of Mo-Co alloy nanowires at various compo-sitions toward replacing irreducible conventional barrier/liner layers.An intermetallic compound formed at a Mo composition of 28.6 at%,the resistivity of the Mo-Co nanowire was(58.0±10.6)μΩcm,indicat-ing its superior electrical and adhesive properties in comparison with those of conventional barriers such as TaN and TiN.Furthermore,density functional theory and non-equilibrium Green's function calcula-tions confirmed that the vertical resistance of the via structure constructed from Mo-based materials was 21%lower than that of a conventional Cu/Ta/TaN structure.

Electrical resistivity evolution in electrodeposited Ru and Ru-Co nanowires

Nanoscale ruthenium(Ru)-based materials are promising replacements for existing multilayered Cu interconnects in integrated circuits.However,it is not easy to apply the results of previously reported studies directly to the electrochemical damascene process because the previous studies have mainly focused on thin flms by dry deposition.Here,we report the electrical resistivity and microstructure of electrodeposited Ru nanowires.We estimate that the resistivity value of a 10 nm diameter Ru nanowire to be71.6μΩcm after analyzing the resistivity values of individual nanowires with various diameters.Furthermore,we investigate the electrical properties of Ru_(x)Co_(1-x)nanowires where x is 0.04–0.99 at.%as possible replacements of the current Ta N barrier structures.Over the entire composition range,the resistivity values of alloys are much lower than that of the conventional Ta N.Additionally,Ru and Ru-alloy nanowires surrounded by dielectric silica are thermally stable after 450°C heat treatment.Therefore,the nanoscale Ru and Ru-Co alloys possessing low resistivity values can be candidates for the interconnect and barrier materials,respectively.