Physical vapor deposition
Physical vapor deposition (PVD) is a variety of vacuum deposition and is a general term used to describe any of a variety of methods to deposit thin films by the condensation of a vaporized form of the desired film material onto various workpiece surfaces (e.g., onto semiconductor wafers). The coating method involves purely physical processes such as high temperature vacuum evaporation with subsequent condensation, or plasma sputter bombardment rather than involving a chemical reaction at the surface to be coated as in chemical vapor deposition. The term physical vapor deposition appears originally in the 1966 book Vapor Deposition by CF Powell, JH Oxley and JM Blocher Jr, but Michael Faraday was using PVD to deposit coatings as far back as 1838.
Variants of PVD include, in order of increasing novelty:
- Cathodic Arc Deposition: In which a high power electric arc discharged at the target (source) material blasts away some into highly ionized vapor to be deposited onto the workpiece.
- Electron beam physical vapor deposition: In which the material to be deposited is heated to a high vapor pressure by electron bombardment in "high" vacuum and is transported by diffusion to be deposited by condensation on the (cooler) workpiece.
- Evaporative deposition: In which the material to be deposited is heated to a high vapor pressure by electrically resistive heating in "low" vacuum.
- Pulsed laser deposition: In which a high power laser ablates material from the target into a vapor.
- Sputter deposition: In which a glow plasma discharge (usually localized around the "target" by a magnet) bombards the material sputtering some away as a vapor for subsequent deposition. Here is an animation of a generic PVD sputter tool: PVD Animation
PVD is used in the manufacture of items including semiconductor devices, aluminized PET film for balloons and snack bags, and coated cutting tools for metalworking. Besides PVD tools for fabrication special smaller tools mainly for scientific purposes have been developed. They mainly serve the purpose of extreme thin films like atomic layers and are used mostly for small substrates. A good example are mini e-beam evaporators which can deposit monolayers of virtually all materials with melting points up to 3500°C.
The source material is unavoidably also deposited on most other surfaces interior to the vacuum chamber, including the workholders.
Some of the techniques used to measure the physical properties of PVD coatings are:
See thin-film deposition for a more general discussion of this class of manufacturing technique.
See also
References
- Anders, Andre (editor). Handbook of Plasma Immersion Ion Implantation and Deposition. New York: Wiley-Interscience, 2000. ISBN 0471246980.
- Bach, Hans, and Dieter Krause (editors). Thin Films on Glass. Schott series on glass and glass ceramics. London: Springer-Verlag, 2003. ISBN 3540585974.
- Bunshah, Roitan F. (editor). Handbook of Deposition Technologies for Films and Coatings: Science, Technology and Applications, second edition. Materials science and process technology series. Park Ridge, N.J.: Noyes Publications, 1994. ISBN 0815513372.
- Gläser, Hans Joachim. Large Area Glass Coating. Dresden: Von Ardenne Anlagentechnik, 2000. ISBN 3000049533.
- Glocker, David A., and S. Ismat Shah (editors). Handbook of Thin Film Process Technology (2 vol. set). Bristol, U.K.: Institute of Physics Pub, 2002. ISBN 0750308338.
- Mahan, John E. Physical Vapor Deposition of Thin Films. New York: John Wiley & Sons, 2000. ISBN 0471330019.
- Mattox, Donald M. Handbook of Physical Vapor Deposition (PVD) Processing: Film Formation, Adhesion, Surface Preparation and Contamination Control.. Westwood, N.J.: Noyes Publications, 1998. ISBN 0815514220.
- Mattox, Donald M. The Foundations of Vacuum Coating Technology. Norwich, N.Y.: Noyes Publications/William Andrew Pub., 2003. ISBN 0815514956.
- Mattox, Donald M. and Vivivenne Harwood Mattox (editors). 50 Years of Vacuum Coating Technology and the Growth of the Society of Vacuum Coaters. Albuquerque, N.M.: Society of Vacuum Coaters, 2007. ISBN 978-1878068279.
- Powell, Carroll F., Joseph H. Oxley, and John Milton Blocher (editors). Vapor Deposition. The Electrochemical Society series. New York: Wiley, 1966.
- Westwood, William D. Sputter Deposition. AVS Education Committee book series, v. 2. New York: Education Committee, AVS, 2003. ISBN 0735401055.
- Willey, Ronald R. Practical Monitoring and Control of Optical Thin Films. Charlevoix, MI: Willey Optical, Consultants, 2007. ISBN 978-0615137605.
- Willey, Ronald R. Practical Equipment, Materials, and Processes for Optical Thin Films. Charlevoix, MI: Willey Optical, Consultants, 2007. ISBN 978-0615143972.
External links