The thesis is organized as follows: In Chapter 2 a detailed description of the photolithography process is presented. Alternative non-optical lithography techniques are also briefly discussed. Chapter 3 provides an introduction into photolithography simulation. Simulation tasks as well as the fundamentals of any photolithography simulator are described. The subsequent four chapters are devoted to various aspects of photolithography simulation. Chapter 4 deals with the aerial image formation and simulation, Chapter 5 outlines the photoresist exposure/bleaching reaction. In Chapter 6 a novel three-dimensional method for rigorous nonplanar photolithography exposure simulation is presented. Chapter 7 focuses on the photoresist development process. Mathematical details of the applied simulation methods can be found in the appendices. In Chapter 8 examples for aerial image simulation as well as for photoresist exposure/bleaching and development are shown. The thesis concludes with a brief discussion of the achieved results and gives some outlook for future work.