Semifabrication

Semifabrication, often shortened to "semifab," refers to the manufacturing of integrated circuits (ICs) in a highly specialized and complex environment. It involves the intricate process of creating semiconductor devices on silicon wafers, which are then sold to other companies for further processing and assembly into finished electronic components. This stage of production is distinct from the design of the ICs and the final packaging and testing of the chips.

The core of semifabrication occurs in a fabrication plant, commonly known as a "fab." These facilities are incredibly expensive to build and operate, requiring highly controlled environments, known as cleanrooms, to prevent even microscopic dust particles from contaminating the sensitive manufacturing processes. Key operations within a fab include photolithography, etching, deposition, and ion implantation, all performed with extreme precision. These steps gradually build up the complex three-dimensional structures that form the transistors and interconnects of an IC.

Companies that specialize in semifabrication are called foundries. They typically do not design their own chips but rather manufacture designs provided by fabless semiconductor companies. This business model allows fabless companies to focus on chip design and marketing without the massive capital investment required for a fabrication facility. Foundries also often serve integrated device manufacturers (IDMs) who design, manufacture, and sell their own chips, but may outsource some of their production to foundries to increase capacity or access specialized manufacturing technologies. The output of a semifabrication plant is a wafer containing many identical ICs, ready to be cut into individual chips.