Two-dimensional simulation of local oxidation of silicon: Calibrated viscoelastic flow analysis

Local Oxidation of Silicon (LOGOS) remains the common isolation technology for mass-production of integrated circuits, The work reported in this paper contributes to the improvement of the numerical modeling of the LOGOS process, A physical two-dimensional (2-D) modeling of the thermal oxidation of silicon has been developed based on the explicit treatment of the reaction expansion. The originality of this modeling is to propose a general solution taking into account of the silicon deformation, incorporating the viscoelastic behavior of oxide and nitride and, particularly, giving a complete calibration of the stress-dependent parameters. The prediction capabilities are demonstrated by the calculations of oxide shapes and oxidation-induced stresses in silicon substrate for very advanced isolation techniques.