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IC Mask
A photomask is an opaque plate with holes or transparencies that allow light to shine through in a defined pattern. They are commonly used in photolithography and the production of integrated circuits (ICs or "chips") in particular. Masks are used to produce a pattern on a substrate, normally a thin slice of silicon known as a wafer in the case of chip manufacturing. Several masks are used in turn, each one reproducing a layer of the completed design, and together they are known as a mask set. Previously, photomasks used to be produced manually by using rubylith and mylar. As complexity continued to grow, manual processing of any sort became difficult. This was solved with the introduction of the optical pattern generator which automated the process of producing the initial large-scale pattern, and the step-and-repeat cameras that automated the copying of the pattern into a multiple-IC mask. The intermediate masks are known as reticles, and were initially copied to production mas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Photomask
A semiconductor is a material which has an electrical conductivity value falling between that of a conductor, such as copper, and an insulator, such as glass. Its resistivity falls as its temperature rises; metals behave in the opposite way. Its conducting properties may be altered in useful ways by introducing impurities (" doping") into the crystal structure. When two differently doped regions exist in the same crystal, a semiconductor junction is created. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called "metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others. Silicon is a critical element for fabricat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
