TABLE OF CONTENTS The semiconductor fabrication process involves several steps such as diffusion, oxidation, ion implantation, etching, deposition and the lithographic steps of image transfer and photoresist exposure and development. Integrated circuits are manufactured by using these sequential fabrication process steps that have their scientific foundations in applied physics and chemistry. Each process is a complex physical phenomenon and, as a result, the exact physics may not always be accurately defined. A long sequence of fabrication steps are necessary to build up the layers on the silicon substrate and to etch them into appropriate shapes to form diodes, transistors and interconnects. Each step has to be precisely controlled to give the best circuit performance and the complete sequence needs to be highly optimised for the production of ICs.
Today much of the development of semiconductor devices and processes is done by TCAD as it offers unique possibilities in visualisation of processing steps, description of the physical changes and understanding of the interrelation of the process variables. Modelling of processes provides a way to interactively explore the fabrication process, studying the effects of process choices, leading to a 'virtual wafer fabrication' (VWF) design environment.
TCAD simulation tools provide a controlled and repeatable numerical experiment that can yield information that cannot be measured experimentally. The main aim of a TCAD simulator tool is to match the simulation methodology as close as possible to the fabrication technology and their integration into the actual fabrication. For TCAD tools to be useful in a practical environment, they...
