An integrated circuit manufacturer produces semiconductor electronic circuits, which are small solid-state electronic components used in mobile phones, televisions and many other electronic devices. Solid-state devices have no moving parts, and are made from silicon-based chips that provide computing and electrical processing capability. Semiconductors replaced vacuum tubes and early mechanical computer switches in the mid-20th century, allowing devices to become very small, yet contain a great deal of computing power.
Production of integrated circuits requires several steps and carefully controlled manufacturing conditions to prevent contamination. The integrated circuit manufacturer builds clean rooms that use very high levels of air filtration to remove dust and other contaminants that can ruin a circuit. Employees wear coverings that prevent dust, skin or hair from entering the process area, and will remove and replace these coverings if they must leave and re-enter the production area.
The first step in producing integrated circuits is creating silicon wafers used as the base of the circuit. An integrated circuit manufacturer or an outside contractor purifies silicon from natural sands, removing any impurities to create a cylinder-shaped crystal made from pure silicon. The cylinder is then cut into thin wafers, which may be several inches or centimeters across. These wafers are chemically cleaned, and then one side is polished to a mirror-like finish that will be the base of the integrated circuit.
Polished wafers are then exposed to pure oxygen in a process that creates a very thin layer of silicon dioxide. Oxygen reacts with the pure silicon on the wafer, which consumes a small amount of the silicon on the wafer surface. The resulting silicon dioxide is molecularly bound to the pure silicon beneath it, and will not be removed later except by chemical processing.
The next steps used by an integrated circuit manufacturer are a repeated process of masking, light exposure, etching and cleaning. An integrated circuit is an electronic circuit formed by thin layers of electrically conducting material separated by layers of non-conductors. Masking places a template or design of the first circuit layer onto the silicon wafer.
First, a material called photoresist is placed on the wafer surface, with the mask over it. The photoresist is exposed to light, which causes a chemical curing reaction of any exposed material. When the mask is removed, the uncured photoresist can be removed in a process called etching.
An integrated circuit manufacturer repeats these steps, adding layers of conductor or non-conductor onto the wafer to build electronic circuits. Many small integrated circuits are made on a wafer at one time, and are cut apart in later steps once the circuits have been completed. The final steps are adding electrical connections to the individual circuits so they can be placed on circuit boards used in computers and other electronic devices.