The study of the structural stability of multilayer systems by RBS and PIXE microbeam methods

Abstract

The thermal stability, inter-diffusion and interface effects in multilayer systems are important parameters as they affect the durability of electromigration properties of integrated circuits. Thermal stability and mixing of Mo Cu interfaces for Mo Cu multilayered systems after annealing up to 700°C for 1 h in a nitrogen atmosphere was studied. The experimental data hint at the significant grain boundary diffusion of Cu in Mo polycrystalline layers under annealing at 400°C. During annealing at higher temperature the grain boundary diffusion is accompanied by new compounds formation. The X-ray diffraction (XRD) data revealed the presence of compounds of CuMoO and CuMoN type. The crash of the film has been observed after annealing at temperatures above 500°C and the areas of silicon on top of the sample has been found. The average size of silicon locations in diameter is depending on the annealing temperature and was estimated as 8 and 16 μm for 600°C and 700°C, respectively. The concentration ratio fluctuations of CMo CCu in some locations have been observed and determined too. © 1995.