| AVS 56th International Symposium & Exhibition | |
| Plasma Science and Technology | Wednesday Sessions |
| Session PS1-WeA |
| Session: | Plasma Modeling |
| Presenter: | J.A. Kenney, Applied Materials |
| Authors: | J.A. Kenney, Applied Materials P.J. Stout, Applied Materials S. Rauf, Applied Materials K. Collins, Applied Materials |
| Correspondent: | Click to Email |
As high aspect ratio (HAR) etch requirements continue to grow more stringent, it has become increasingly important to understand the influence of reactor design and process conditions on three closely intertwined areas: plasma uniformity; fluxes, energies, and angular distributions of species exiting the plasma and impinging on the wafer; and profile evolution of the HAR features. Due to the complexities and uncertainties involved in experimental analysis of these topics, many modeling efforts have been directed at each. Here, we investigate the unique aspects arising when each realm is considered fully in three dimensions in the context of a capacitively coupled plasma (CCP) reactor, with an emphasis on ion angular and energy distribution functions (IAEDFs).
Our efforts include a three-dimensional fluid plasma model, a Monte Carlo-based particle simulation for charged species, and a three-dimensional Monte Carlo-based feature profile evolution tool. The plasma model provides spatially and temporally-resolved species densities, species fluxes, and electric fields. The particle simulation uses that information in turn to generate ions in the bulk plasma and track them as they are influenced by the time-varying electric fields as well as collisions with other species. The energy and three-dimensional angle for ions striking the wafer are recorded and binned as appropriate. The feature profile evolution tool uses this data along with the species fluxes from the plasma model as inputs and includes a variety of physics and chemistry, including ion-enhanced etching, ion sputtering, ion scattering, etch product desorption, and the formation of surface layers.
In this work, we demonstrate the influences of externally applied magnetic fields and azimuthally asymmetric reactor components in CCP systems on the resulting IAEDFs. To isolate the impact of these features, we consider simple etch-relevant feed gas mixtures (Ar, Ar/CF4, Ar/O2) and single (162 MHz) and dual frequency (2/60 MHz) configurations. We analyze both the differences between the IAEDFs generated with and without these features as well as differences found between locations within a single wafer. We then examine the linkage between these differences and the results from the feature profile evolution tool.