Refractory metals can be used in a number of ways in the electronics market. Ion Implantation, Physical Vapor Deposition (PVD), Metalorganic Chemical Vapor Deposition (MOCVD) and Molecular Beam Epitaxy (MBE) are just some of the semiconductor manufacturing applications that can use precision-machined parts in either assembled or part forms.
Ion implantation is the injection of the ion beam with an energy order of 100keV into a material where the ion beam will have a series of physical and chemical interactions with atoms or molecules in the material. The incident ions gradually lose their energy, and finally stop in the material and cause a change in composition, structure and properties of the surface of the material, thus optimizing the surface properties of the material, or giving some new excellent performance to the material.
Evaporation deposition (PVD)
A form of physical vapor deposition (PVD) called evaporation deposition is used to deposit thin films onto substrates through the evaporation of the film material and further condensation of the vapor onto said substrate, usually thin films on small substrates. The deposition of aluminum on semiconductor wafers is extremely efficient and doesn’t risk damaging the substrate. Other uses include depositing aluminized film for balloons, snack bags, and the coating of cutting tools in metalworking.
The process proceeds as follows: In a vacuum chamber, film material is stored in small boats and heated to a point where the material vaporizes. The resulting vapor is then mixed with a gas to form a compound which is then condensed onto the substrate as a highly adherent coating. During the process, molybdenum boats are used because they can withstand the heat needed to vaporize the pure metals and corrosion from the resulting gaseous compounds.
Metal Organic Chemical Vapor Deposition (MOCVD) and Molecular Beam Epitaxy (MBE)
To grow crystalline layers on substrates for compound semiconductors multilayer structures, MOCVD and MBE chemical vapor deposition methods can be used to deposit solid films of complex organometallic compounds such as GaAs, GaN, AlGaAs, AlGaInP and InGaN on sapphire wafers. MOCVD occurs in gas phase at pressures of 2-100 kPa while MBE travels through a vacuum of 10-8 PA before condensing on the substrate. These methods are now used in major manufacturing processes for LED semiconductors, cell phone transistors, and WiFi and solar cells.
The heated gas of individual compounds is mixed with heated gas and then deposits onto the substrate. The excess gas is exhausted out of the chamber and liquidized for disposal. In the chemically aggressive gallium arsenide (GaAs) environment of MOCVD reactors, molybdenum is most useful due to it’s high temperature tolerance and relative nobility.
Some products include exhaust rings, wafer support trays, attachments, and evaporation boats for specialist wafer coatings. Of these products, wafer support trays, which are manufactured from 1.5-3.0 mm sheets, have the largest volume. Since these carrier are present in the deposition chambers and exposed to the chemicals and temperatures, they are a consumable item.