Semiconductor foundry fundamentals
Semiconductor foundry services design and manufacture semiconductor chips on a contract basis, in prototype to production quantities. Some companies produce silicon wafers for analog devices, application-specific integrated circuits (ASIC), high voltage components, logic gates, microprocessors, or computer memory. Others fabricate chips and wafers for oscillators, transistor-oscillators (TO), passive components, power electronics, sensors, or micro-electrical mechanical systems (MEMS). Semiconductor foundry services are located across North America and around the world. They manufacture semiconductors for a variety of market segments, including: aerospace, biotechnology, computers, telecommunications, and transportation. Chip manufacture for imaging or vision systems and wireless, radio frequency (RF) and microwave devices is also available.
Semiconductor foundry services perform processes such as chemical mechanical polishing (CMP), physical vapor deposition (PVD), chemical vapor deposition (CVD), screen printing, dry etching, wet etching, photolithography, wafer level packaging, and via forming or filling. CMP is used for the planarization of deposited structures. PVD deposits thin films by physical methods and includes techniques such as evaporation and sputtering. CVD is a thin-film deposition process in which gaseous chemical precursors form deposits of oxides, nitrides, dielectric ceramics or other complex compounds. Screen printing uses a metal paste or ink to form thick-film circuits or interconnects. Dry etching processes such as plasma or reactive ion etching (RIE) remove layers from or cut patterns into substrates. Wet etching also forms or cuts substrate patterns, but uses acids or other chemical solutions. Photolithography transfers a circuit pattern onto a substrate by using a patterned mask and beam of light to selectively expose a photoresist layer. Wafer level packaging uses solder bumping or redistribution line technology (RDL). Via forming and via filling creates patterned circuits or vias in a ceramic substrate for the interconnection of electronic components and packaging of dies.
Semiconductor foundry services differ in terms of capabilities. Companies that provide semiconductor design and engineering services can assist with manufacturing costs and the selection of wafer materials for custom chips. They may also be able to assist in upgrading or redesigning, re-evaluating or modernizing existing products to increase performance and/or reduce manufacturing costs. Companies that provide research and development (R & D) services can help meet application requirements by identifying factors or properties required for the control of material-critical components. Prototyping services build short runs of representative wafers for use in presentations and functional testing. Pilot or scale-up services provide initial pilot runs or low-volume production. Semiconductor foundry services that provide high-volume production and chip fabrication are also available.
Semiconductor foundry services produce semiconductor chips and silicon wafers for many different logic families. Examples include transistor-transistor logic (TTL), Fairchild Advanced Schottky TTL (FAST), emitter coupling logic (ECL), gallium arsenide (GaAs), indium phosphide (InP), silicon on sapphire (SOS) silicon on insulator (SOI), and integrated injection logic (IIL). Complementary metal-oxide semiconductor (CMOS) logic uses a combination of p-type and n-type metal-oxide-semiconductor field effect transistors (MOSFET) to implement logic gates and other digital circuits found in computers, telecommunications and signal processing equipment. CMOS variants include CMOS4000, advanced CMOS (AC), high-speed CMOS (HCMOS), and low-voltage CMOS (LV). BiCMOS combines the high speed of bipolar TTL with the low power consumption of CMOS.