Fabrication of an IC-Integrated Circuit (even thinner than human hair)

An integrated circuit, also referred to as IC, chip, or microchip, is an electronic circuit manufactured by the patterned diffusion of trace elements into the surface of a thin substrate of semiconductor material. Additional materials are deposited and patterned to form interconnections between semiconductor devices.

Semiconductor device fabrication is the process used to create the integrated circuits that are present in everyday electrical and electronic devices. It is a multiple-step sequence of photolithographic and chemical processing steps during which electronic circuits are gradually created on a wafer made of pure semiconducting material. Silicon is almost always used, but various compound semiconductors are used for specialized applications.

Transistors and connection(in IC) are made from many layers (typical 10 to 15 in CMOS) built on top of one another. Each layer has a special pattern defined by a mask. One important aspect of an IC is the length of a smallest transistor that can be fabricated. It was measured in micron (um, 10^-6 meter) and now is in nm (10^-9 meter)
E.g., we may say an IC is built with 32 nm process. In comparison, the diameter of human hair is about 100 um (i.e.,100,000 nm)
Very intersting lecture on Fabrication of an IC-Integrated Circuit (specifically MOSFET) from an Indian University I found on youtube: