Profile evolution simulations during chemical vapor deposition based on a 2D continuum model reveal that the type of surface kinetics plays an important role in determining step coverage of films deposited in high aspect ratio trenches and vias. Linear surface kinetics, resulting from an adsorption rate limited process, is found to cause difficulty in bringing about conformal step coverage in deep narrow trenches without reducing the growth rate considerably. Under such condition, void-free filling cannot be achieved while maintaining a growth rate acceptable to integrated circuit (IC) manufacturing. The numerical study also suggests that the high tendency of the precursor for chemical equilibrium on a surface, resulting in nonlinear kinetics by a surface reaction limited process, is crucial to achieve a uniform step coverage as typically observed in SiO2 deposition from tetraethylorthosilicate (TEOS).

Profile evolution simulations during chemical vapor deposition based on a 2-D continuum model reveal that the type of surface kinetics plays an important role as a measure of determining step coverage of films deposited in a high aspect ratio trench or via. The linear surface kinetics, resulting from adsorption rate limitation, is found to be difficult to bring about conformal step coverage in a deep narrow trench without reducing the growth rate considerably; that is, under such a condition void free filling can not be achievable with holding an appropriate growth rate. High tendency of the precursor for chemical equilibrium on a surface, tending to cause the non-linear surface kinetics by surface reaction limitation, is mainly responsible for the significant improvement of step coverage in TEOS-based depositions.

Deposition of a thin film in the LPCVD process has been simulated by a Monte–Carlo method based on a simple model taking into account the desorption, the surface reaction, and the surface migration of the film precursor. The model has been used for the simulation of the film profile obtained in a narrow and deep trench and of the film crystallinity on a flat surface. The simulation results describe successfully those obtained by experiments under various process conditions.