Semiconductor Industry is the maindriving force for technology innovation and "New Economy" markets. Theongoing development of faster integrated circuits with higher devicedensity has led to highly complex and sophisticated products whichare widely accepted by society. A modern integrated circuit cannotbe developed without the massive use of computer aided design (CAD)in any step of the complex flow from the idea to the final product. Thiswork concentrates on technology computer aided design (TCAD) and itsintegration into the semiconductor fabrication process flow. An analysis of the current semiconductor manufacturing flow and its implications on how TCAD can be integrated into it is shown. By doing a structured approach it is demonstrated how such a system can be implemented in real conditions. Furthermore the flexibility and advantages of the integration is shown by a couple of real examples. This book is intended to be a reference to TCAD engineers which are facing support requests from manufacturing and to manufacturing engineers to get new ideas of how TCAD can be used in their every day business.