Boult Wade Tennant
Ion implantation apparatus and method of implanting ions to prevent charge build up on a substrate
In ion implantation processes, secondary electrons are emitted from a substrate in an ion implanter during ion implantation and have the effect of producing excessive negative charge build up on the substrate damaging the substrate. An apparatus and a method is provided in which the negative charge build up on the substrate is restricted by extending a magnetic filter across the ion beam between a substrate holder and a plasma flood source of the ion implanter to deflect the secondary electrons with higher energies above about 15 eV out of the ion beam to be absorbed by a conductive element, preventing re-attachment of the high energy secondary electrons to the substrate and allowing lower energy electrons below about 15 eV, which are necessary for neutralising positive charge build up on the substrate caused by the ion beam, to diffuse across the magnetic filter without being deflected out of the ion beam.
Applied Materials, Inc.
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inventional additional additional
Hiroyuki
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