Effect of Thin Films on Radiative Transport in Chemical Vapor Deposition Systems

The thermal behavior of a wafer during a Rapid Thermal Chemical Vapor Deposition (RTCVD) process depends on its spectral radiative properties, along with other factors. One of the major contributing factors is the thin film that is deposited on the wafer substrate. The presence of a thin film (of thickness anywhere above 0.1 nm) can drastically alter the radiative properties of the wafer surface, thereby leading to significantly different wafer temperatures. This article presents a model to simulate thin film effects in RTCVD processes. Radiative transfer is modeled using a Monte-Carlo ray-tracing technique. Radiative properties are calculated using fundamental Electromagnetic Wave Theory. Simulation results match remarkably well with experimental data, demonstrating the importance of thin film effects.