Effect of surface kinetics on the step coverage during chemical vapor deposition

Profile evolution simulations during chemical vapor deposition based on a 2 D continuum model reveal that the type of surface kinetics plays an importa nt role in determining step coverage of films deposited in high aspect rati o trenches and vias. Linear surface kinetics, resulting from an adsorption rate limited process, is found to cause difficulty in bringing about confor mal step coverage in deep narrow trenches without reducing the growth rate considerably, Under such condition, void-free filling cannot be achieved wh ile maintaining a growth rate acceptable to integrated circuit (IC) manufac turing. The numerical study also suggests that the high tendency of the pre cursor for chemical equilibrium on a surface, resulting in nonlinear kineti cs by a surface reaction limited process, is crucial to achieve a uniform s tep coverage as typically observed in SiO2 deposition from tetraethylorthos ilicate (TEOS).