Front end of line

BEOL (metalization layer) and FEOL (devices).
CMOS fabrication process

The front-end-of-line (FEOL) is the first portion of IC fabrication where the individual devices (transistors, capacitors, resistors, etc.) are patterned in the semiconductor.[1] FEOL generally covers everything up to (but not including) the deposition of metal interconnect layers.

FEOL contains all processes of CMOS fabrication needed to form fully isolated CMOS elements:

  1. Selecting the type of wafer to be used; Chemical-mechanical planarization and cleaning of the wafer.
  2. Shallow trench isolation (STI) (or LOCOS in early processes, with feature size > 0.25 μm)
  3. Well formation
  4. Gate module formation
  5. Source and drain module formation

See also


  1. ^ Karen A. Reinhardt and Werner Kern (2008). Handbook of Silicon Wafer Cleaning Technology (2nd ed.). William Andrew. p. 202. ISBN 978-0-8155-1554-8.

Further reading

  • "CMOS: Circuit Design, Layout, and Simulation" Wiley-IEEE, 2010. ISBN 978-0-470-88132-3. pages 177-178 (Chapter 7.2 CMOS Process Integration); pages 180-199 (7.2.1 Frontend-of-the-line integration)

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