Numerical Calculations on the Low Pressure Behavior of a High Density Plasma CVD Reactor

Abstract

Summary form only given. High-density plasma CVD (HDP-CVD) reactors are used to provide void-free gap fill of high-quality dielectric films in high aspect ratio device structures. The ability to accurately model a prototype or development design is an important capability of any equipment manufacturer in order to lower cost and shorten design cycle times. However, the ability to accurately model an HDP-CVD tool remains a difficult challenge due to the complex coupling of power deposition and plasma transport in a CVD chamber. In this study, we compare two types of numerical algorithms on the accuracy of predicting power deposition and electron transport inside a low pressure, high plasma density CVD reactor. The two codes used are Hybrid Plasma Equipment Model (HPEM) and the non-PDPSIM code, both developed at the Iowa State University. The HPEM enables the solution of the electromagnetic fields that are used to generate electron energy distribution functions (EEDF). The EEDF's are used to generate sources for electron impact processes and electron transport coefficients. Momentum and continuity equations are solved for all heavy particles. The electron temperature is solved through the electron energy equation, while a drift diffusion formulation is used for electrons to enable an implicit solution of Poisson's equation for the electric potential. However, the HPEM has limitations on its ability to simulate a complex geometry since it is implemented on a recti-linear mesh. The non-PDPSIM code also solves full momentum equations for all heavy particles and similar algorithms for EEDF and transport coefficients. Yet, the non-PDPSIM code is implemented on an unstructured mesh capable of capturing a large dynamic range in length scale.