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Products
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Plasma Etcher
Etching is used in microfabrication to chemically remove layers from the
surface of a wafer during manufacturing. Etching is a critically important
process module, and every wafer undergoes many etching steps before it is
complete.
If the etch is intended to make a cavity in a material, the depth of the
cavity may be controlled approximately using the etching time and the known
etch rate. More often, though, etching must entirely remove the top layer of a
multilayer structure, without damaging the underlying or masking layers. The
etching system's ability to do this depends on the ratio of etch rates in the
two materials (selectivity).
Some etches undercut the masking layer and form cavities with sloping sidewalls.
The distance of undercutting is called bias. Etchants with large bias are
called isotropic.
Modern VLSI processes avoid wet etching, and use plasma etching instead.
Plasma systems can operate in several modes by adjusting the parameters of
the plasma. Ordinary plasma etching operates between 0.1 and 5 Torr. (This
unit of pressure, commonly used in vacuum engineering, equals approximately
133.3 pascals) The plasma produces energetic free radicals, neutrally
charged, that react at the surface of the wafer. Since neutral particles
attack the wafer from all angles, this process is isotropic.
The source gas for the plasma usually contains small molecules rich in
chlorine or fluorine. For instance, carbon tetrachloride (CCl4) etches
silicon and aluminium, and trifluoromethane etches silicon dioxide and
silicon nitride. A plasma containing oxygen is used to oxidize
("ash") photoresist and facilitate its removal.
We can provide the following refurbished plasma Etcher equipment.
We provide our own proprietary AW
Control Software and Superior Temperature
Control Technology to upgrade the refurbished equipment which provides the
following significant advantages.
- Integrated process
control system
- Real time graphics
display
- Real time process data
acquisition, display, and analysis
- Programmed
comprehensive calibration and diagnostic functions
- Better performance and
maintenance than the original systems
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