CMOS Process steps

Modern processes often have more than twenty mask levels with more
than one hundred processing steps. These steps are classified as either frontend
or back-end processing. Front-end processing refers to the formation of
the transistors directly on the silicon. Back-end processing is the creation of
metal interconnecting wires, which are isolated by insulating materials, to
connect the transistor formations.

Some process steps are

Silicon crystal growth

Wet cleaning


Ion implantation

Dry etching

Wet etching

Plasma etching

Thermal treatments (rapid thermal annealing, furnace annealing, and

Chemical vapor deposition

Physical vapor deposition

Molecular beam epitaxy

Electrochemical deposition


Chemical–mechanical planarization

Wafer testing

Wafer backgrinding

Wafer mounting

Die cutting