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Overlay Control
In silicon wafer manufacturing overlay control is the control of pattern-to-pattern alignment necessary in the manufacture of silicon wafers. Silicon wafers are currently manufactured in a sequence of steps, each stage placing a pattern of material on the wafer; in this way transistors, contacts, etc., all made of different materials, are laid down. In order for the final device to function correctly, these separate patterns must be aligned correctly – for example contacts, lines and transistors must all line up. Overlay control has always played an important role in semiconductor manufacturing, helping to monitor layer-to-layer alignment on multi-layer device structures. Misalignment of any kind can cause short circuits and connection failures, which in turn impact fab yield and profit margins. Overlay control has become even more critical now because the combination of increasing pattern density and innovative techniques such as double patterning and 193 nm immersion lith ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silicon Wafer
In electronics, a wafer (also called a slice or substrate) is a thin slice of semiconductor, such as a crystalline silicon (c-Si), used for the fabrication of integrated circuits and, in photovoltaics, to manufacture solar cells. The wafer serves as the substrate for microelectronic devices built in and upon the wafer. It undergoes many microfabrication processes, such as doping, ion implantation, etching, thin-film deposition of various materials, and photolithographic patterning. Finally, the individual microcircuits are separated by wafer dicing and packaged as an integrated circuit. History In the semiconductor or silicon wafer industry, the term wafer appeared in the 1950s to describe a thin round slice of semiconductor material, typically germanium or silicon. Round shape comes from single-crystal ingots usually produced using the Czochralski method. Silicon wafers were first introduced in the 1940s. By 1960, silicon wafers were being manufactured in the U.S. by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transistor
upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch electrical signals and electrical power, power. The transistor is one of the basic building blocks of modern electronics. It is composed of semiconductor material, usually with at least three terminals for connection to an electronic circuit. A voltage or current applied to one pair of the transistor's terminals controls the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Some transistors are packaged individually, but many more are found embedded in integrated circuits. Austro-Hungarian physicist Julius Edgar Lilienfeld proposed the concept of a field-effect transistor in 1926, but it was not possible to actually constru ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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