Analysis of Flow Fields in a Deposition Chamber by a Molecular Approach

Abstract

In this Ph.D Thesis a computing procedure is proposed as possible tool to simulate and analyze the flow field in a thin film deposition apparatus similar to the van de Sanden deposition apparatus at the University of Eindhoven. A sensitivity analysis of test parameters (electrical power supplied to the torch, precursor mass flow rate, thermo-fluid-dynamic quantities at the inlet chamber section by means of different nozzle geometry) on fluidics is evaluated. More over a method is proposed for a very preliminary evaluation of the film thickness distribution on the substrate and the influence of the above test parameters on film distribution is carried out. The computing procedure is based on two codes working in tandem. The first code is a pre-processor and simulates the flow field in the torch, where Argon is ionized according to the Saha’s equation and in part of the nozzle. The second code is the commercial DS2V code based on Direct Simulation Monte Carlo method and simulates the flow field in the remaining part of nozzle and in the whole chamber. Gas is a mixture of 21 chemical species and 24 chemical reactions from Argon plasma and Acetylene are implemented in both codes. Results show that the effects of the electrical power as well as of the mass flow rate look to be not very strong on the shock wave intensity, while are not negligible on the shock wave thickness. For what concern the film distribution, the sensitivity analysis verifies that the higher is electrical power and the precursor mass flow rate, the ticker and less uniform is the film.