3 Device Fabrication Technology1 CHAPTER OBJECTIVES

While the previous chapters explain the properties of semiconductors, this chapter will explain how devices are made out of the semiconductors. It introduces the basic techniques of defining physical patterns by lithography and etching, changing the doping concentration by ion implantation and diffusion, and depositing thin films over the semiconductor’s substrate. One section describes the techniques of fabricating the important metal interconnection structures. It is useful to remember the names of the key techniques and their acronyms, as they are often used in technical discussions. With rapid miniaturization and efficient high-volume processing, over 1019 transistors (or a billion for every person in the world) are produced every year. Massive integration of transistors has made complex circuits in the form of integrated circuits (ICs) inexpensive and a wide range of electronic applications practical and affordable. Semiconductor devices are responsible for the arrival of the “computer age ” or the “second industrial revolution. ” At the heart of the information and communication technologies, ICs of all descriptions also find applications in consumer electronics, automobiles, medical equipment, and industrial electronics. As a result, semiconductor devices are making contributions to every segment of the global economy and every branch of human endeavors.1 Many large semiconductor companies both design and fabricate ICs. They are called integrated semiconductor companies. An even larger number of companies only design the circuits. They are called fabless design companies. They leave the fabrication to silicon foundries, which specialize in manufacturing. So an IC company may or may not fabricate the chips that they design. 1 Readers who are more interested in devices than fabrication technology may proceed to Chapter 4 after reading the introduction and Section 3.1 of this chapter. Some subsequent chapters will refer back to specific parts of Chapter 3 and afford the reader the opportunity to pick up the needed information on fabrication technology