Photolithography
Photolithography is a process used in semiconductor manufacturing to create patterns and features on the surface of a silicon wafer. The process uses light to transfer a pattern from a photomask onto a wafer using a light-sensitive material known as photoresist. The equipment used in photolithography varies depending on the specific process being used, but typically includes exposure tools, aligners, etching equipment, and inspection tools.
One of the most significant recent advancements in photolithography is the introduction of Extreme Ultraviolet (EUV) lithography. EUV lithography uses extremely short-wavelength light, with a wavelength of around 13.5 nanometers, which allows for much smaller feature sizes than traditional lithography techniques. The equipment used for EUV lithography is highly specialized and includes light sources, mirrors, and masks that are designed to operate at this extremely short wavelength.
Another important development in lithography is the use of high-NA (numerical aperture) lenses. High-NA lenses are used to improve the resolution of lithography equipment by allowing for a wider range of angles of light to be collected and focused on the wafer. This improves the ability of the equipment to create smaller and more precise features on the wafer. High-NA lenses require specialized design and fabrication techniques, and are typically made using materials such as fluorite, calcium fluoride, or synthetic quartz.
The lithography process typically involves several steps, including photomask design, photolithography, photoresist exposure, developing, etching, and photoresist stripping. Each of these steps is critical to the success of the lithography process, and requires specialized equipment and expertise to achieve the desired results:
Photomask Design: The first step is to design a photomask, which is a high-resolution image of the desired pattern. The photomask is typically created using a specialized computer-aided design (CAD) software.
Photolithography:
The photomask is then used in a process called photolithography. The wafer is coated with a layer of photoresist, which is a light-sensitive material that can be chemically altered to create patterns. The photomask is then placed over the wafer, and light is projected through the mask and onto the photoresist.Photoresist Exposure: When the light hits the photoresist, it undergoes a chemical reaction that alters its solubility. This creates a pattern of exposed and unexposed areas on the photoresist, which correspond to the desired pattern.
Developing: The wafer is then submerged in a chemical developer solution that removes the exposed areas of the photoresist, leaving behind a patterned layer of photoresist.
Etching: The patterned layer of photoresist is then used as a mask to etch away the underlying layers of the wafer, creating the desired pattern on the surface of the wafer. This etching process can be done using a variety of techniques, including wet etching, dry etching, or plasma etching.
Photoresist Stripping: Finally, the remaining photoresist is stripped away using a chemical solution, leaving behind the patterned layers on the surface of the wafer.
Other chemicals and compounds used during the semiconductor manufacturing process include:
| Chemical / Compounds |
|---|
| (L)-Ethyl lactate |
| 1,1,1-Trichloroethane |
| 1,2-Dichloroethylene, all isomers |
| 1-Methoxy-2-propyl acetate |
| 1-Nitropropane |
| 2,2,6,6-Tetrabromobisphenol A |
| 2,4,6,8-Tetramethylcyclotetrasiloxane |
| 2-Butanone |
| 2-Butoxyethanol |
| 2-Ethoxyethanol |
| 2-Ethoxyethyl acetate |
| 2-Methoxyethanol |
| 2-Methylimidazole |
| 4-Chloro-2-methylphenol |
| Acetic acid |
| Acetone |
| Acetonitrile |
| Alloy 42 |
| Aluminum |
| Aluminum |
| Aluminum nitride |
| Aluminum phosphide |
| Aluminum tris(8-hydroxyquinoline) |
| Ammonia |
| Ammonium fluoride |
| Ammonium persulfate |
| Anatase |
| Antimony |
| Antimony |
| Antimony trichloride |
| Antimony trioxide |
| Argon |
| Arsenic |
| Arsenic pentafluoride |
| Arsenic trioxide |
| Arsenic trisulfide |
| Arsine |
| Bis(dimethylamino)dimethylsilane |
| Bismuth |
| Bismuth telluride |
| Bismuth telluride |
| Bisphenol A |
| Boron |
| Boron Nitride |
| Boron nitride |
| Boron oxide |
| Boron tribromide |
| Boron trichloride |
| Boron trifluoride |
| Borophosphosilicate glass |
| Cadmium |
| Cadmium oxide |
| Cadmium selenide |
| Cadmium sulfide |
| Cadmium telluride |
| Carbon tetrachloride |
| Chromium |
| Chromium trioxide |
| Chromium(III) oxide |
| Cobalt |
| Cobaltic-cobaltous oxide |
| Cobaltous oxide |
| Colophony |
| Copper |
| Copper Indium Gallium Selenide (CIGS) |
| Copper(II) oxide |
| Cupric sulfide |
| Cuprous selenide |
| Cyclohexyl methacrylate |
| Decaborane |
| Diborane |
| Dichlorosilane |
| Diethanolamine |
| Diethyl oxalate |
| Diethylene glycol dimethyl ether |
| Diethylene glycol monobutyl ether |
| Diethylsilane |
| Dimethyl acetamide |
| Dimethyl sulfoxide |
| Dimethylamine borane |
| Dimethylformamide |
| Dodecyl and tetradecyl glycidyl ethers |
| Epichlorohydrin |
| Ethanolamine |
| Ethyl lactate |
| Ethyl silicate |
| Ethyl-3-ethoxypropionate |
| Formaldehyde |
| Gallium |
| Gallium |
| Gallium arsenide |
| Gallium Manganese Arsenide (GaAs) |
| Gallium nitride |
| Gallium oxide |
| Gallium phosphide |
| Gallium trichloride |
| Germanium |
| Germanium dioxide |
| Germanium telluride |
| Germanium tetrachloride |
| Germanium tetrafluoride |
| Germanium tetrahydride |
| Gold |
| Hafnium |
| Helium |
| Hexachlorodisilane |
| Hexafluorobutadiene |
| Hexamethyldisilazane |
| Hydrazine |
| Hydrogen chloride |
| Hydrogen fluoride |
| Hydrogen peroxide |
| Hydrogen selenide |
| Indium |
| Indium arsenide |
| Indium nitride |
| Indium phosphide |
| Isopropyl alcohol |
| Kovar |
| Lead |
| Lead titanate |
| Lead zirconate titanate |
| Lead(II) sulfide |
| Lead(II) telluride |
| Manganese(II) oxide |
| Manganese(III) oxide |
| Melamine |
| Mercuric telluride |
| Mercury(II) selenide |
| Methyl alcohol |
| Methyl cellosolve acetate |
| Methyl formate |
| Methylchloro-isothiazolinone |
| Molybdenum disilicide |
| Molybdenum Disulfide |
| N-(2-Hydroxyethyl)ethylenediamine |
| n-Butyl acetate |
| n-Butyl alcohol |
| N-Methyl-2-pyrrolidone |
| Nickel |
| Nickel carbonyl |
| Nickel(II) oxide |
| Nitric acid |
| Nitrobenzene |
| Nitrogen trifluoride |
| Octamethyltrisiloxane |
| Oxirane |
| Pentaborane |
| Pentaerythritol triacrylate |
| Perfluoro compounds, C5-18 |
| Perfluoroisobutylene |
| Perfluorooctane sulfonic acid |
| Perfluorotributylamine |
| Perylene |
| Phenol |
| Phenol-formaldehyde resin |
| Phosphine |
| Phosphoric acid |
| Phosphorus (yellow) |
| Phosphorus oxychloride |
| Phosphorus pentafluoride |
| Phosphorus pentoxide |
| Phosphorus tribromide |
| Phosphorus trichloride |
| Platinum silicate |
| Platinum, soluble salts |
| Polysilicon |
| Potassium hydroxide |
| Propargyl alcohol |
| Quartz |
| Rhenium |
| Rubidium |
| Sapphire |
| Scandium |
| Scandium nitride |
| Selenium hexafluoride |
| Selenourea |
| Sichrome |
| Silica, amorphous |
| Silicic acid |
| Silicon |
| Silicon Carbide (SiC) |
| Silicon dioxide |
| Silicon nitride |
| Silicon nitride |
| Silicon tetrachloride |
| Silicon tetrahydride |
| Silver |
| Sodium hydroxide |
| Stibine |
| Stoddard solvent |
| Strontium titanate |
| Sulfolane |
| Sulfuric acid |
| Tellurium |
| tert-Butylarsine |
| Tetrafluoroboric acid |
| Tetramethyl ammonium hydroxide |
| Tetramethylsilane |
| Thallium |
| Thallium selenide |
| Tin |
| Tin(II) oxide |
| Tin(IV) oxide |
| Titanium dioxide |
| Titanium nitride |
| Toluene |
| Trichlorosilane |
| Triethyl borate |
| Triethylindium |
| Trifluoro(tetrahydrofuran)boron |
| Trimellitic anhydride |
| Trimethylaluminum |
| Trimethylborane |
| Trimethylgallium |
| Trimethylindium |
| Tungsten |
| Vinyltrimethylsilane |
| Xylene isomers |
| Zinc chloride fume |
| Zinc oxide |
| Zinc telluride |
| Zirconium boride |
