Analysis of transport phenomena in plasma enhanced chemical vapor deposition reactor

Abstract

The goal of this thesis is to understand the transport phenomena and reaction mechanism in the reactors of common CVD and plasma process used in the semiconductor manufacturing by analyzing them through the numerical simulation. This objective has been met by constructing the mathematical models describing the fluid flow structure, temperature distribution and mass transport of reacting species in the reactor, and especially electromagnetic field distribution and transport of charged particle for plasma equipment and simulating numerically through these pseudo-steady-state models. Transport phenomena in a vertical reactor for metalorganic chemical vapor deposition (MOCVD) of copper thin films have been analyzed by numerical simulation of the process for the gas flow structure, temperature distribution and concentration distribution of the reacting species. Deposition rates of copper thin films using Cu(hfac)VTMS as a precursor were estimated from numerical solutions. Standard process conditions were selected as: a reactor pressure of 1 Torr, a substrate temperature and inlet gas temperature of 200℃ and 70℃, respectively, and an inlet gas flow rate of 50 sccm. Under standard conditions, the deposition rates of copper were in the range of 160-230Å/min. The effects of the process conditions, reactor geometry and shower head structure on the deposition rate and thickness uniformity were examined. It has been demonstrated that numerical simulation can be used for improving the film thickness uniformity and the utilization of source gas. It is expected that high density plasma (HDP) source will be used to produce the activated reactant. These HDP sources have the difficulty of obtaining good uniformity of the reaction rate in a substrate. In this study the gas velocity distributions in an asymmetric chamber were predicted by three dimensional modeling and computer simulation for gas flow. Axisymmetric gas flow in the asymmetric chamber could be obtained by controllin...