Plasma flood system for the reduction of charging of wafers during ion implantation
AssigneeApplied Materials, Inc.
InventorsHiroyuki Ito, Jonathan England, Frederick Plumb, Ian Fotheringham
Life of this patent
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Abstract
A plasma flood system for use in the implantation of ions in a semiconductor substrate comprising a plasma and low energy electron source for developing a plasma containing low energy electrons for magnetic field enhanced transmission to a negatively biased, magnetic field assisted electron confinement tube and into an ion beam flowing axially through the tube to the semiconductor substrate for self regulating and neutralizing positive charges on the surface of the substrate without causing significant negative charging of the substrate.
Claims24
An electron flood system for neutralizing positive charge buildup on a substrate during implantation of ions in the substrate, comprising:
- an electron confinement tube axially receiving and passing an ion beam to a substrate;
- a plasma generation chamber containing a gas for forming a plasma containing low energy electrons and having an exit aperture in communication with an open of the electron confinement tube to pass the low energy electrons into the tube to join the ion beam passing therethrough;
- and
- means for negatively biasing the electron confinement tube relative to the substrate to negatively shield the chamber, to control the passage of the low energy electrons into the electron confinement tube, and to contain and intensify the flow of the low energy electrons within and along the ion beam to the substrate to thereby neutralize positive charges on the substrate.
An electron flood system for use in the implantation of ions in a semiconductor substrate, comprising:
- a low energy electron source;
- and
- an electron confinement tube for receiving and passing an ion beam to a semiconductor substrate and including an inlet for receiving electrons from the low energy electron source, a portion of said electron confinement tube adjacent said electron source being negatively biased relative to said low energy electron source.
A plasma flood system for use in the implantation of ions in a semiconductor substrate, comprising:
- a plasma source for forming a plasma containing low energy electrons;
- an electron confinement tube is negatively biased relative to said semiconductor substrate for receiving and passing an ion beam to the semiconductor substrate and including an inlet for receiving the plasma from the plasma source;
- first magnetic means for enhancing production of the low energy electrons within and passage thereof through the inlet with the plasma into the electron confinement tube to flow with the ion beam to the semiconductor substrate to affect a neutralization of positive charge on the substrate;
- and
- second magnetic means along the tube for generating magnetic fields which enhance electron confinement along the tube to the semiconductor substrate.
An electron flood system used in an ion implantation system for implanting ions from an ion beam into a substrate, comprising:
- a guide tube extending along an axis, receiving said ion beam along said axis, and delivering along said axis said ion beam to said substrate and said guide tube is negatively biased relative to said substrate;
- an electron generator generating electrons and delivering said electrons to said ion beam obliquely to said axis;
- and
- first magnetic means along said guide tube adjacent to said electron generator for generating magnetic fields confining said electrons to a vicinity of said ion beam.
An electron flood system used in an ion beam system processing a substrate, comprising:
- a holder of a substrate;
- a tube axially passing an ion beam therethrough and negatively biased relative to said holder;
- and
- an electron source communicating through a first aperture in a side wall of said tube to supply electrons emitted from said electron source therethrough to said ion beam.
Dependencies are inferred from the claim text.