This chapter argues that modern integrated circuit (IC) manufacturing easily represents the most intricate piece of human engineering ever successfully conducted. The modern IC begins and ends in the IC fabrication facility, the “wafer fab,” and involves seven major types of operations, each of which must be routinely executed with almost unbelievable dexterity. In early IC manufacturing, solid-state diffusion was the preferred means of doping crystals. Beyond 3D packaging lies “system-on-package”, more complicated still, since it might contain several system-on-a-chip ICs, radio frequency transceivers for wireless communications, microelectromechanical systems sensors and actuators, memory, an optical interface, optical waveguides, and even ICs built from different types of semiconductors. The metal-oxide semiconductor field-effect transistor (MOSFET) fab sequence would be called a “five-mask process”. This is the sort of MOSFET that good universities will actually allow students to go into the lab and learn how to build themselves during a one-semester course in micro/nano fabrication.