Modeling of SiO₂ deposition from mixtures of tetraethoxysilane and ozone in an APCVD industrial reactor

Abstract
The deposition of silicon dioxide by Atmospheric Pressure Chemical Vapor Deposition using TEOS/Ozone chemistry in an industrial linear-injector reactor has been modeled. The objective was to optimize the operating conditions. ESTET, a French commercial CFD software, has been used to solve the hydrodynamics and heat transport problems. The software has been modified to take into account mass transport and chemical reactions both in the gas phase and on surfaces. Thus, the model enables us to predict the deposition rate and the operating conditions influences. The first results obtained will be discussed and compared with experimental data. The shields in the deposition chambers appear to play an important role in avoiding recirculation regions, and then minimizing undesirable risks of homogeneous nucleation and particle formation. Important thermal gradients are localized in a thin thermal boundary layer near the hot wafer surface. Deposition is mainly due to intermediate species produced by oxidation of TEOS in the gas phase. Some discrepancies remain between experimental and simulation results : at this time, they can be attributed to uncertainties in the chemical model used, which has not been established in exact industrial conditions.