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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. The entire manufacturing process, from start to packaged chips ready for shipment, takes six to eight weeks and is performed in highly specialized facilities referred to as fabs. List of steps This is a list of processing techniques that are employed numerous times in a modern electronic device and do not necessarily imply a specific order. Wafer processing Wet cleans Photolithography Ion implantation (in which dopants are embedded in the wafer creating regions of increased (or decreased) conductivity) Dry etching Wet etching Plasma ashing Thermal treatments
Furnace anneals Thermal oxidation Physical vapor deposition (PVD) Molecular beam epitaxy (MBE) Electrochemical deposition (ECD). See Electroplating Chemical-mechanical planarization (CMP) Wafer testing (where the electrical performance is verified) Wafer backgrinding (to reduce the thickness of the wafer so the resulting chip can be put into a thin device like a smartcard or PCMCIA card.) Die preparation
Die cutting Die attachment IC bonding
Thermosonic bonding Flip chip Wafer bonding Tab bonding
Plating Lasermarking Trim and form Hazardous materials Many toxic materials are used in the fabrication process.These include: poisonous elemental dopants such as arsenic, antimony and phosphorus poisonous compounds like arsine, phosphine and silane highly reactive liquids, such as hydrogen peroxide, fuming nitric acid, sulfuric acid and hydrofluoric acid It is vital that workers not be directly exposed to these dangerous substances. The high degree of automation common in the IC fabrication industry helps to reduce the risks of exposure of this sort. Most fabrication facilities employ exhaust management systems, such as wet scrubbers, combustors, heated absorber cartridges etc., to control the risk to workers and also the environment if these toxic materials are released into the atmosphere. |