1.2 Outline of this Thesis

The first part of this thesis deals with the mentioned problem of tool integration for both, the internal and the "inter-vendor" scenarios. As a solution a data model which is implemented in the WAFER-STATE-SERVER is presented. The WAFER-STATE-SERVER is realized as a C++ class library that can be used to solve many problems common to the whole range of TCAD simulators. These problems include I/O operations, meshing, and other algorithms essential and handy for TCAD simulators. The final target of the tool integration aims at simulating a whole flow of a semiconductor fabrication process where tools are exchangeable. It should be possible to exchange a simulator performing a specific step with any other suitable simulator that is available.

The second part of this thesis deals with all kind of optimization aspects for TCAD purposes. The WAFER-STATE-SERVER thereby acts as an aid to perform complex high level simulation tasks (e.g. optimization). As an optimization may consist of several thousand single simulation runs, it obviously cannot be performed by starting the simulators by hand. The aspects discussed in this part of the thesis are the calibration of a process- or device simulator, and inverse modeling, i.e. the extraction of the dopant profile of a transistor. Several optimization strategies are investigated and compared in terms of performance, i.e. the number of simulator runs to achieve a desired minimum, and robustness, which can be seen as the amount of human interaction that is necessary to perform the optimization. Finally, the framework that is used to launch the optimization and to spread the jobs over a heterogeneous cluster of workstations is presented.

Chapter 2 discusses problems arising in the coupling of process simulators. First, an overview of which data are commonly needed by a TCAD simulation tool and thus, are stored on a Wafer is given, next the desired operations on that data are presented. The various problems and their solution modules are sketched. In Chapter 3 the concept of the WAFER-STATE-SERVER is presented and a detailed insight into the design of the classes is given. The modules corresponding to the tasks discussed in Chapter 2 are introduced and all available implementations are presented. In Chapter 4 applications of the WAFER-STATE-SERVER and examples of process simulations are shown.

Chapter 5 comprises the second part of this thesis and presents the available optimization framework and the supported optimization tools. A comparison of optimization strategies is given.
Appendix A presents the application programming interface (API) of the WAFER-STATE-SERVER, Appendix B describes the grammar of the native ASCII file format (WSS) and of the Config file. Appendix C briefly presents the implemented solution that is used for an automated compilation and error diagnosis of all software parts

Chapter 6 concludes the thesis with a summary.