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Phenomenological Single-Particle
Modeling of Reactive Transport
in Semiconductor Processing

1.2 Outline

This thesis follows the didactic structure of first introducing concepts and then expanding them into applications. Thus, the ordering of the chapters does not necessarily follow their chronological order of development and original publication. Instead, their arrangement is chosen to provide a more natural narrative for the reader.

Initially, Chapter 2 briefly reviews topography simulation and the basic categories of approaches to calculate the reactive transport. After this broad overview, one specific approach to generate one-dimensional (1D) models, Knudsen diffusion, is presented in Chapter 3 in its historic context with a focus on clarifying lingering misconceptions. Knudsen diffusive transport is re-derived using a more modern formulation including an analogy to radiative heat transfer to incorporate more physical phenomena as well as two brief applications.

Then, attention is shifted to applying the presented models to specific etching and deposition processes and to the adequate interpretation of the model parameters.
First, Chapter 4 presents an application of Knudsen diffusive transport models to the thermal ALP, including its novel integration with LS based topography simulation. Chapter 5 investigates the process of low-bias SF6 plasma etching of Si, evaluating the applicable approaches proposed in Chapter 2 and proposing a new empirical relationship between experimental topographical measurements and the phenomenological model parameters.

Finally, Chapter 6 culminates the thesis by performing an even deeper investigation of the low-bias SF6 plasma etching process in order to optimize an actual device: Silicon microcavity resonators. The issue of requiring manual calibration is addressed with a developed custom feature detection and automatic calibration procedure. Finally, the power of topography simulation is showcased in practice by exploring the impact of different etch time regimes on parameters linked to device performance. The concluding remarks and outlook for possible future research directions are discussed in Chapter 7.