Axcelis Technologies, Inc.

William K Loizides

Alexander S Perel

Thomas N Horsky

Victor M Benveniste

Lyudmila Stone

The present invention is directed to in-situ detection of particles and other such features in an ion implantation system during implantation operations to avoid such additional monitoring tool steps otherwise expended before and/or after implantation, for example. One or more such systems are revealed for detecting scattered light from particles on one or more semiconductor wafers illuminated by a light source (e.g., laser beam). The system comprises an ion implanter having a laser for illumination of a spot on the wafer and a pair of detectors (e.g., PMT or photodiode) rotationally opposite from the ion implantation operations. A wafer transport holds a wafer or wafers for translational scanning under the fixed laser spot. A computer analyzes the intensity of the scattered light detected from the illuminated wafer (workpiece), and may also map the light detected to a unique position. For example, particles or other such contaminates may be identified on wafers during the implantation process before additional time and resources are consumed, and aid in determining the sources of such contaminates. Further, threshold analysis of the quantity or size of such particles, for example, may provide a system interlock for shutdown or feedback control.

[object Object]

An ion source () for an ion implanter is provided, comprising a remotely located vaporizer () and an ionizer () connected to the vaporizer by a feed tube (). The vaporizer comprises a sublimator () for receiving a solid source material such as decaborane and sublimating (vaporizing) the decaborane. A heating mechanism is provided for heating the sublimator, and the feed tube connecting the sublimator to the ionizer, to maintain a suitable temperature for the vaporized decaborane. The ionizer () comprises a body () having an inlet () for receiving the vaporized decaborane; an ionization chamber () in which the vaporized decaborane may be ionized by an energy-emitting element () to create a plasma; and an exit aperture () for extracting an ion beam comprised of the plasma. A cooling mechanism () is provided for lowering the temperature of walls () of the ionization chamber () (e.g., to below 350&#xb0; C.) during ionization of the vaporized decaborane to prevent dissociation of vaporized decaborane molecules into atomic boron ions. In addition, the energy-emitting element is operated at a sufficiently low power level to minimize plasma density within the ionization chamber () to prevent additional dissociation of the vaporized decaborane molecules by the plasma itself.

Decaborane ion source

An ion source (,) for an ion implanter is provided, comprising a remotely located vaporizer (,) and an ionizer (,) connected to the vaporizer by a feed tube (,). The vaporizer comprises a sublimator (,) for receiving a solid source material such as decaborane and sublimating (vaporizing) the decaborane. A heating mechanism is provided for heating the sublimator, and the feed tube connecting the sublimator to the ionizer, to maintain a suitable temperature for the vaporized decaborane. The ionizer (,) comprises a body (,) having an inlet (,) for receiving the vaporized decaborane; an ionization chamber (,) in which the vaporized decaborane may be ionized by an energy-emitting element (,) to create a plasma; and an exit aperture (,) for extracting an ion beam comprised of the plasma. A cooling mechanism (,) is provided for lowering the temperature of walls (,) of the ionization chamber (,) (e.g., to below 350&deg; C.) during ionization of the vaporized decaborane to prevent dissociation of vaporized decaborane molecules into atomic boron ions. In addition, the energy-emitting element is operated at a sufficiently low power level to minimize plasma density within the ionization chamber (,) to prevent additional dissociation of the vaporized decaborane molecules by the plasma itself.

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Lee, NH, United States of America

William K Loizides