No abstract

Ruthenium (Ru) exhibits excellent electrical properties at the nanoscale, and it can be used to replace Al and Cu as interconnect metals for nodes of 20 nm and below in the next generation of integrated circuits. Ru interconnects mainly exist in the form of films, and Ru targets are used as the key raw materials to produce these films. Establishing whether there is an inheritance relationship in terms of microstructure and electrical properties between these targets and the resultant films will determine whether these are important factors for improving the electrical properties of Ru films and will provide directional guidance for the preparation of Ru targets. In this work, Ru targets were prepared by vacuum hot pressing with two different Ru powders with different morphologies and particle sizes. Ru films were then deposited on SiO2/Si(100) substrates by RF magnetron sputtering at substrate temperatures ranging from room temperature (RT, about 25 °C) to 400 °C. The microstructures and electrical properties of the Ru targets and Ru films were investigated by high-resolution field-emission scanning electron microscopy, x ray diffraction, atomic force microscopy, four-probe resistivity measurements, and digital conductivity tests. The results showed that Ru targets with a more uniform microstructure had lower resistivity; furthermore, Ru films deposited by Ru targets with a more uniform microstructure were preferentially crystallized, and they also had a faster average deposition rate, a smaller average grain size, and lower surface roughness. However, no correlation was found between the crystal orientations of the Ru films and Ru targets.

Sputtering target is commonly used in semiconductor manufacturing for the preparation of thin films. Cold rolling and annealing treatment of bulk Ag is the routine process to prepare Ag sputtering target. In this paper, the microstructure evolution of Ag after cold rolling and annealing treatment was studied, and the results showed that annealing temperature affects the recrystallized structure of Ag and that 600 °C/1 h treatment can achieve complete recrystallization. At the same time, the texture evolution was also observed and discussed.

In this study, pure copper’s hot deformation behavior was studied through isothermal compression tests at deformation temperatures of 350~750 °C with strain rates of 0.01~5 s−1 on a Gleeble-3500 isothermal simulator. Metallographic observation and microhardness measurement were carried out of the hot compressed specimens. By analyzing the true stress–strain curves of pure copper under various deformation conditions during the hot deformation process, the constitutive equation was established based on the strain-compensated Arrhenius model. On the basis of the dynamic material model proposed by Prasad, the hot-processing maps were acquired under different strains. Meanwhile, the effect of deformation temperature and strain rate on the microstructure characteristics was studied by observing the hot-compressed microstructure. The results demonstrate that the flow stress of pure copper has positive strain rate sensitivity and negative temperature correlation. The average hardness value of pure copper has no obvious change trend with the strain rate. The flow stress can be predicted with excellent accuracy via the Arrhenius model based on strain compensation. The suitable deforming process parameters for pure copper were determined to be at a deformation temperature range of 700~750 °C and strain rate range of 0.1~1 s−1.