A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word laser is an anacronym that originated as an acronym for light amplification by stimulated emission of radiation. The first laser was built in 1960 by Theodore Maiman at Hughes Research Laboratories, based on theoretical work by Charles H. Townes and Arthur Leonard Schawlow.
A laser is constructed from three principal parts:
The noble gases are the naturally occurring members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Under standard conditions, these elements are odorless, colorless, monatomic gases with very low chemical reactivity and cryogenic boiling points.
Photolithography 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.
Ultraviolet (UV) light is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight, and constitutes about 10% of the total electromagnetic radiation output from the Sun. It is also produced by electric arcs, Cherenkov radiation, and specialized lights, such as mercury-vapor lamps, tanning lamps, and black lights.
An excimer is a short-lived polyatomic molecule formed from two species that do not form a stable molecule in the ground state. In this case, formation of molecules is possible only if such atom is in an electronic excited state. Heteronuclear molecules and molecules that have more than two species are also called exciplex molecules. Excimers are often diatomic and are composed of two atoms or molecules that would not bond if both were in the ground state. The lifetime of an excimer is very short, on the order of nanoseconds.
In chemistry, noble gas compounds are chemical compounds that include an element from the noble gases, group 18 of the periodic table. Although the noble gases are generally unreactive elements, many such compounds have been observed, particularly involving the element xenon.
An excimer laser, sometimes more correctly called an exciplex laser, is a form of ultraviolet laser which is commonly used in the production of microelectronic devices, semiconductor based integrated circuits or "chips", eye surgery, and micromachining.
A gas laser is a laser in which an electric current is discharged through a gas to produce coherent light. The gas laser was the first continuous-light laser and the first laser to operate on the principle of converting electrical energy to a laser light output. The first gas laser, the Helium–neon laser (HeNe), was co-invented by Iranian engineer and scientist Ali Javan and American physicist William R. Bennett, Jr., in 1960. It produced a coherent light beam in the infrared region of the spectrum at 1.15 micrometres.
An ion laser is a gas laser that uses an ionized gas as its lasing medium. Like other gas lasers, ion lasers feature a sealed cavity containing the laser medium and mirrors forming a Fabry–Pérot resonator. Unlike helium–neon lasers, the energy level transitions that contribute to laser action come from ions. Because of the large amount of energy required to excite the ionic transitions used in ion lasers, the required current is much greater, and as a result almost all except for the smallest ion lasers are water-cooled. A small air-cooled ion laser might produce, for example, 130 milliwatts of output light with a tube current of about 10 amperes and a voltage of 105 volts. Since one ampere times one volt is one watt, this is an electrical power input of about one kilowatt. Subtracting the (desirable) light output of 130 mW from power input, this leaves the large amount of waste heat of nearly one kW. This has to be dissipated by the cooling system. In other words, the power efficiency is very low.
Nanolithography (NL) is a growing field of techniques within nanotechnology dealing with the engineering of nanometer-scale structures on various materials.
A stepper or wafer stepper is a device used in the manufacture of integrated circuits (ICs). It is an essential part of the process of photolithography, which creates millions of microscopic circuit elements on the surface of silicon wafers out of which chips are made. It is similar in operation to a slide projector or a photographic enlarger. The ICs that are made form the heart of computer processors, memory chips, and many other electronic devices.
The Nike laser at the United States Naval Research Laboratory in Washington, DC is a 56-beam, 4–5 kJ per pulse electron beam pumped krypton fluoride excimer laser which operates in the ultraviolet at 248 nm with pulsewidths of a few nanoseconds. Nike was completed in the late 1980s and is used for investigations into inertial confinement fusion. By using a KrF laser with induced spatial incoherence (ISI) optical smoothing, the modulations in the laser focal profile are only 1% in one beam and < 0.3% with a 44-beam overlap. This feature is especially important for minimizing the seeding of Rayleigh-Taylor instabilities in the imploding fusion target capsule plasma.
Krypton difluoride, KrF2 is a chemical compound of krypton and fluorine. It was the first compound of krypton discovered. It is a volatile, colourless solid at room temperature. The structure of the KrF2 molecule is linear, with Kr−F distances of 188.9 pm. It reacts with strong Lewis acids to form salts of the KrF+ and Kr
2F+
3 cations.
Krypton is a chemical element; it has symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. Krypton is chemically inert.
Computational lithography is the set of mathematical and algorithmic approaches designed to improve the resolution attainable through photolithography. Computational lithography came to the forefront of photolithography technologies in 2008 when the semiconductor industry faced challenges associated with the transition to a 22 nanometer CMOS microfabrication process and has become instrumental in further shrinking the design nodes and topology of semiconductor transistor manufacturing.
The argon fluoride laser is a particular type of excimer laser, which is sometimes called an exciplex laser. With its 193-nanometer wavelength, it is a deep ultraviolet laser, which is commonly used in the production of semiconductor integrated circuits, eye surgery, micromachining, and scientific research. "Excimer" is short for "excited dimer", while "exciplex" is short for "excited complex". An excimer laser typically uses a mixture of a noble gas and a halogen gas, which under suitable conditions of electrical stimulation and high pressure, emits coherent stimulated radiation in the ultraviolet range.
Xenon monochloride (XeCl) is an exciplex which is used in excimer lasers and excimer lamps emitting near ultraviolet light at 308 nm. It is most commonly used in medicine. Xenon monochloride was first synthesized in the 1960s. Its kinetic scheme is very complex and its state changes occur on a nanosecond timescale. In the gaseous state, at least two kinds of xenon monochloride are known: XeCl and Xe
2Cl, whereas complex aggregates form in the solid state in noble gas matrices. The excited state of xenon resembles halogens and it reacts with them to form excited molecular compounds.
An excimer lamp is a source of ultraviolet light based on spontaneous emission of excimer (exciplex) molecules.
Shanghai Micro Electronics Equipment (Group) Co., Ltd. (SMEE), is a semiconductor manufacturing equipment company based in Shanghai, China. The company is involved in the research, development, manufacture and sale of lithography scanners and inspection tools to the semiconductor manufacturing industry; it also provides support services to its customers.
