Characterisation of the local stress induced by shallow trench isolation and CoSi2 silicidation

With further down-scaling below 0.25/im technologies, CoSi₂ is replacing TiSii because of its superior formation chemistry on narrow lines and favourable stress behaviour. Shallow trench isolation (STI) is used as the isolation technique in these technologies. In this study, convergent beam electron diffraction (CBED) measurements and finite element modelling (FEM) are performed to evaluate the local stress components in the silicon substrate, induced in STI structures with a 45 nm or a 85 nm CoSi₂ silicidation. High compressive stresses in the active area and tensile stress around the trench comers are observed.