Microlithography is a general name for any manufacturing process that can create a minutely patterned

thin film A thin film is a layer of materials ranging from fractions of a nanometer ( monolayer) to several micrometers in thickness. The controlled synthesis of materials as thin films (a process referred to as deposition) is a fundamental step in many ...

of protective materials over a substrate, such as a

silicon Silicon is a chemical element; it has symbol Si and atomic number 14. It is a hard, brittle crystalline solid with a blue-grey metallic lustre, and is a tetravalent metalloid (sometimes considered a non-metal) and semiconductor. It is a membe ...

wafer, in order to protect selected areas of it during subsequent

etching Etching is traditionally the process of using strong acid or mordant to cut into the unprotected parts of a metal surface to create a design in intaglio (incised) in the metal. In modern manufacturing, other chemicals may be used on other type ...

, deposition, or implantation operations. The term is normally used for processes that can reliably produce features of microscopic size, such as 10

micrometre The micrometre (English in the Commonwealth of Nations, Commonwealth English as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American English), also commonly known by the non-SI term micron, is a uni ...

s or less. The term

nanolithography Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering (patterning e.g. etching, depositing, writing, printing etc) of Nanometre, nanometer-scale structures on various materials. The modern term r ...

may be used to designate processes that can produce nanoscale features, such as less than 100

nanometre 330px, Different lengths as in respect to the Molecule">molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm), or nanometer (American spelling), is a unit of length ...

s. Microlithography is a

microfabrication Microfabrication is the process of fabricating miniature structures of micrometre scales and smaller. Historically, the earliest microfabrication processes were used for integrated circuit fabrication, also known as "semiconductor manufacturing" ...

process that is extensively used in the

semiconductor industry The semiconductor industry is the aggregate of companies engaged in the design and fabrication of semiconductors and semiconductor devices, such as transistors and integrated circuits. Its roots can be traced to the invention of the transistor ...

and also manufacture

microelectromechanical systems MEMS (micro-electromechanical systems) is the technology of microscopic devices incorporating both electronic and moving parts. MEMS are made up of components between 1 and 100 micrometres in size (i.e., 0.001 to 0.1 mm), and MEMS devices ...

Processes

Specific microlithography processes include: *

Photolithography Photolithography (also known as optical lithography) is a process used in the manufacturing of integrated circuits. It involves using light to transfer a pattern onto a substrate, typically a silicon wafer. The process begins with a photosensiti ...

using light projected on a

photosensitive Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicity. ...

material film (

photoresist A photoresist (also known simply as a resist) is a light-sensitive material used in several processes, such as photolithography and photoengraving, to form a patterned coating on a surface. This process is crucial in the electronics industry. T ...

). *

Electron beam lithography Electron-beam lithography (often abbreviated as e-beam lithography or EBL) is the practice of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electron-sensitive film called a resist (exposing). The electron ...

, using a steerable electron beam. * Nanoimprinting *

Interference lithography Interference lithography (or holographic lithography) is a technique that uses coherent light (such as light from a laser) for patterning regular arrays of fine features without the use of complex optics, optical systems or photomasks. Basic prin ...

* Magnetolithography *

Scanning probe lithography Scanning probe lithography (SPL) describes a set of nanolithographic methods to pattern material on the nanoscale using scanning probes. It is a direct-write, mask-less approach which bypasses the diffraction limit and can reach resolutions be ...

* Surface-charge lithography * Diffraction lithography These processes differ in speed and cost, as well as in the material they can be applied to and the range of feature sizes they can produce. For instance, while the size of features achievable with photolithography is limited by the wavelength of the light used, the technique it is considerably faster and simpler than electron beam lithography, that can achieve much smaller ones.

Applications

The main application for microlithography is fabrication of integrated circuits ("electronic chips"), such as solid-state memories and

microprocessor A microprocessor is a computer processor (computing), processor for which the data processing logic and control is included on a single integrated circuit (IC), or a small number of ICs. The microprocessor contains the arithmetic, logic, a ...

s. They can also be used to create

diffraction grating In optics, a diffraction grating is an optical grating with a periodic structure that diffraction, diffracts light, or another type of electromagnetic radiation, into several beams traveling in different directions (i.e., different diffractio ...

s, microscope calibration grids, and other flat structures with microscopic details.

References

John N Helbert (2001), ''Handbook of VLSI Microlithography''. Elsevier Science, 1022 pages. Bruce W. Smith and Kazuaki Suzuki (2007): ''Microlithography: Science and Technology'', 2nd Edition. CRC Press, 864 pages. S. Grilli, V. Vespini, P. Ferraro (2008): "Surface-charge lithography for direct PDMS micro-patterning". ''Langmuir'', volume 24, pages 13262–13265. M. Paturzo, S. Grilli, S. Mailis, G. Coppola, M. Iodice, M. Gioffré, P. Ferraro (2008): "Flexible coherent diffraction lithography by tunable phase arrays in lithium niobate crystals". ''Optics Communications'', volume 281, pages 1950–1953. Integrated circuits Lithography (microfabrication) {{manufacturing-stub

Processes

Applications

See also

References