Introduction to vapor deposition
Vapor deposition is a new manufacturing technique developed in recent 40 years. It is the process that utilize the reaction between gas phase material and substrate, usually solid, to create a very thin film to obtain the specified performance the substrate do not have originally. This technology has been widely used in micro scale manufacturing and it is one of the fundamentals of large scale production of semi-conductor components.
When the deposition process involved with chemical reactions, it was classified as chemical vapor deposition (CVD). If not, it was called physical vapor deposition (PVD). As the advantage of vapor deposition process is to create a thin film (nanometer scale) of certain material on the substrate made by another thing, it is an ideal process to create the tiny wire and other components of modern chips. The material was deposited on substrate (frequently Si wafer) layer by layer with PVD or CVD technology and was etched to the desired shape after (photolithography). As the etching process could be controlled with light, which can be very accurate with optical lenses, components in nano scale is possible to be made. The recent (2017) chips for PC has reached 14nm grade, which is approximately only 70 aluminum (common material for conducting wire in the chips) atoms!
Vapor deposition process is also used to manufacture nano scale materials directly. A typical process to obtain macro scales (inch, centimeter..) graphene film is, using CH3 as the raw material, created by CVD process on copper or nickel sheet. During the process, methane is decomposed by high temperature, with the substrate material serve as catalyst. Solid carbon atoms are left on the substrate while gas phase hydrogen left with gas flow.
Combined with latest accurate photolithography technology, vapor deposition process is technically possible to produce all kinds of tiny components, even mechanics such as so called nano machine, in a very large volume. It is the truth that these technology are the key for next generation manufacturing.