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Chemistry Of Photolithography
Photolithography is a process in removing select portions of thin films used in microfabrication. Microfabrication is the production of parts on the micro- and nano- scale, typically on the surface of silicon wafers, for the production of integrated circuits, microelectromechanical systems (MEMS), solar cells, and other devices. Photolithography makes this process possible through the combined use of hexamethyldisilazane (HMDS), photoresist (positive or negative), spin coating, photomask, an exposure system and other various chemicals. By carefully manipulating these factors it is possible to create nearly any geometry microstructure on the surface of a silicon wafer. The chemical interaction between all the different components and the surface of the silicon wafer makes photolithography an interesting chemistry problem. Current engineering has been able to create features on the surface of silicon wafers between 1 and 100 μm. Silicon wafer Silicon wafers are cut from a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold And Aluminum Solar Cell Manufactured At Cal Poly Microfab Clean Room
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal in a pure form. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Gold often occurs in free elemental ( native state), as nuggets or grains, in rocks, veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium (gold tellurides). Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid), forming a soluble tetrachloroaurate anion. Gold is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithography
Lithography () is a planographic method of printing originally based on the immiscibility of oil and water. The printing is from a stone (lithographic limestone) or a metal plate with a smooth surface. It was invented in 1796 by the German author and actor Alois Senefelder and was initially used mostly for musical scores and maps.Meggs, Philip B. A History of Graphic Design. (1998) John Wiley & Sons, Inc. p 146 Carter, Rob, Ben Day, Philip Meggs. Typographic Design: Form and Communication, Third Edition. (2002) John Wiley & Sons, Inc. p 11 Lithography can be used to print text or images onto paper or other suitable material. A lithograph is something printed by lithography, but this term is only used for fine art prints and some other, mostly older, types of printed matter, not for those made by modern commercial lithography. Originally, the image to be printed was drawn with a greasy substance, such as oil, fat, or wax onto the surface of a smooth and flat limestone plat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photolithography
In integrated circuit manufacturing, photolithography or optical lithography is a general term used for techniques that use light to produce minutely patterned thin films of suitable materials over a substrate, such as a silicon wafer, to protect selected areas of it during subsequent etching, deposition, or implantation operations. Typically, ultraviolet light is used to transfer a geometric design from an optical mask to a light-sensitive chemical (photoresist) coated on the substrate. The photoresist either breaks down or hardens where it is exposed to light. The patterned film is then created by removing the softer parts of the coating with appropriate solvents. Conventional photoresists typically consists of three components: resin, sensitizer, and solvent. Photolithography processes can be classified according to the type of light used, such as ultraviolet, deep ultraviolet, extreme ultraviolet, or X-ray. The wavelength of light used determines the minimum feature si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinner
Technology *Spinner (aeronautics), the aerodynamic cone at the hub of an aircraft propeller * Spinner (cell culture), laboratory equipment for cultivating plant or mammalian cells * Spinner (computing), a graphical widget in a GUI * Spinner (MIT Media Lab), software that can automatically edit video to fit a narrative structure Arts and entertainment * ''Spinner'' (album), a 1995 album by Brian Eno & Jah Wobble *Spinner (Blade Runner), a flying car from the film ''Blade Runner'' People *Spinner (surname) *Brian Spencer (1949–1988), Canadian National Hockey League player nicknamed "Spinner" Fictional characters * Spinner (''My Hero Academia''), a character in the manga series ''My Hero Academia'' *Spinner Mason, in the TV series ''Degrassi: The Next Generation'' *Spinner, in the animated TV series ''Clutch Cargo'' *Dorothy Spinner, a DC Comics character. *Spinner, a villain of Batman from DC Comics Sports and games *Spinner (dominoes), a domino tile that may be played on fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrophobic
In chemistry, hydrophobicity is the physical property of a molecule that is seemingly repelled from a mass of water (known as a hydrophobe). In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thus, prefer other neutral molecules and nonpolar solvents. Because water molecules are polar, hydrophobes do not dissolve well among them. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds. Hydrophobic is often used interchangeably with lipophilic, "fat-loving". However, the two terms are not synonymous. While hydrophobic substances are usually lipophilic, there are exceptions, suc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spin Coater
Spin coating is a procedure used to deposit uniform thin films onto flat substrates. Usually a small amount of coating material is applied on the center of the substrate, which is either spinning at low speed or not spinning at all. The substrate is then rotated at speed up to 10,000 rpm to spread the coating material by centrifugal force. A machine used for spin coating is called a spin coater, or simply spinner. Rotation is continued while the fluid spins off the edges of the substrate, until the desired thickness of the film is achieved. The applied solvent is usually volatile, and simultaneously evaporates. The higher the angular speed of spinning, the thinner the film. The thickness of the film also depends on the viscosity and concentration of the solution, and the solvent. Pioneering theoretical analysis of spin coating was undertaken by Emslie et al., and has been extended by many subsequent authors (including Wilson et al., who studied the rate of spreading in spin coat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hexamethyldisilazane
Bis(trimethylsilyl)amine (also known as hexamethyldisilazane and HMDS) is an organosilicon compound with the molecular formula CH3)3Sisub>2NH. The molecule is a derivative of ammonia with trimethylsilyl groups in place of two hydrogen atoms. An electron diffraction study shows that silicon-nitrogen bond length (173.5 pm) and Si-N-Si bond angle (125.5°) to be similar to disilazane (in which methyl groups are replaced by hydrogen atoms) suggesting that steric factors are not a factor in regulating angles in this case. This colorless liquid is a reagent and a precursor to bases that are popular in organic synthesis and organometallic chemistry. Additionally, HMDS is also increasingly used as molecular precursor in chemical vapor deposition techniques to deposit silicon carbonitride thin films or coatings. Synthesis and derivatives Bis(trimethylsilyl)amine is synthesized by treatment of trimethylsilyl chloride with ammonia: :2 (CH3)3SiCl + 3 NH3 → CH3)3Sisub>2NH + 2 NH4Cl Ammoniu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surface Chemistry Of HMDS
A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is the portion with which other materials first interact. The surface of an object is more than "a mere geometric solid", but is "filled with, spread over by, or suffused with perceivable qualities such as color and warmth". The concept of surface has been abstracted and formalized in mathematics, specifically in geometry. Depending on the properties on which the emphasis is given, there are several non equivalent such formalizations, that are all called ''surface'', sometimes with some qualifier, such as algebraic surface, smooth surface or fractal surface. The concept of surface and its mathematical abstraction are both widely used in physics, engineering, computer graphics, and many other disciplines, primarily in representing the surfac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Contact Angle
The contact angle is the angle, conventionally measured through the liquid, where a liquid–vapor interface meets a solid surface. It quantifies the wettability of a solid surface by a liquid via the Young equation. A given system of solid, liquid, and vapor at a given temperature and pressure has a unique equilibrium contact angle. However, in practice a dynamic phenomenon of contact angle hysteresis is often observed, ranging from the advancing (maximal) contact angle to the receding (minimal) contact angle. The equilibrium contact is within those values, and can be calculated from them. The equilibrium contact angle reflects the relative strength of the liquid, solid, and vapour molecular interaction. The contact angle depends upon the medium above the free surface of the liquid, and the nature of the liquid and solid in contact. It is independent of the inclination of solid to the liquid surface. It changes with surface tension and hence with the temperature and purity of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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