US 5,132,544 A · System for irradiating a surface with atomic and molecular ions using two dimensional magnetic scanning

Abstract

System for irradiating the surface of a substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions over the surface of the substrate. A scanning system is shown for deflecting the beam in two dimensions relative to a reference axis and a magnetic ion beam transport system following the scanning system is arranged to receive the beam from the scanning system over the range of two dimensional deflections of the scanning system and constructed to impose magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to a direction having a predetermined desired relationship with the axis in the two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of the beam over the substrate. One scanning system includes sequential first and second time-variable-field magnetic scanners, the first scanner having a magnetic gap of volume smaller than that of the second scanner and constructed to scan the beam more rapidly than the second scanner. In another system, the scanners are superposed. The magnetic ion beam transport system presently preferred is a system producing a sequence of three or more quadrupole fields, implemented by a sequence of quadrupoles. Alternate structures are disclosed. The system is capable of depositing atomic or molecular ions with a desired angular and positional uniformity over a wide range of perveance including perveance above 0.02/M[amu].sup.1/2 (mA//keV.sup.3/2) with a constant, adjustable spot size and small beam spread.

Claims94

Dependent claims

An ion implantation system for doping a substrate, by irradiating a surface of the substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions over the substrate, the system including:

an end station for presenting a substrate to the ion beam,
an ion source and associated beam-forming devices for producing a beam of atomic or molecular ions,
a magnetic scanning system for deflecting the ion beam in two dimensions relative to a reference axis, said scanning system employing, for each dimension of scan, a single respective scanning magnet means formed of a yoke and pole means of magnetic material and associated energizing coils,
and a magnetic ion beam transport system following the scanning system and preceding said end station, said transport system arranged to determine the angular relationship with which ions reach and are implanted into said substrate at said end station,
said transport system arranged to receive the beam from the scanning system over the range of two dimensional deflections of said scanning system and constructed to impose static magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to an implanting direction having a predetermined desired angular relationship with the axis in each of said two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of the beam over the substrate.

2 more elements

System for depositing atomic or molecular ions with a desired uniformity by rapid scanning of a beam over a wide range of perveance including perveance above 0.02/M[amu].sup.1/2 (mA/keV.sup.3/2) over the surface of a substrate, the system including:

an end station supporting the substrate,
an ion source for producing a beam of atomic or molecular ions,
beam forming devices for producing a beam of atomic or molecular ions including a momentum analyzer for removing, from the beam, ions of unwanted momentum and an accelerator for establishing the desired final velocity of the ions,
a magnetic scanning system for deflecting the beam in two dimensions relative to a reference axis;
said scanning system including:
first and second time-variable-field magnetic scanners in first and second positions along the axis of the system for successively deflecting the beam in respective dimensions, the first scanner constructed to rapidly scan the beam in the first dimension, said first scanner having a magnetic gap through which the beam passes of volume smaller than the volume of the magnetic gap of said second scanner and constructed to scan the beam more rapidly than the second scanner,
the scanners effective at each instant to deflect the beam from said reference axis in a decoupled manner at respective angles in the respective dimensions that are determined by the desired instantaneous displacement of the beam on the substrate;
each of said magnetic scanners comprised of yoke and pole means of magnetic material and associated energizing coils,
and each having a respective deflection circuit and power supply for applying time-varying current to said coil,
and a magnetic ion beam transport system following the scanners,
said transport system arranged to receive the beam from the scanners over the range of two dimensional deflections of said scanners and constructed to impose static magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam in a dimensionally decoupled manner, to a direction having a predetermined desired angular relationship with the axis in said two directions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of a beam spot of finite ion-distributing size over the substrate,
said magnetic ion beam transport system constructed to provide at the substrate a beam of substantially constant beam size at said substrate in which directions of travel of the ions deviate by less than about 2.degree. from a desired direction over the range of scan.

9 more elements

System for irradiating a surface of a substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions over the substrate, the system including:

an end station for presenting a substrate to the beam,
an ion source and associated beam-forming devices for producing a beam of atomic or molecular ions,
a magnetic scanning system for deflecting the beam in two dimensions relative to a reference axis, said system employing, for each dimension of scan, a single scanning magnet means formed of a yoke and pole means of magnetic material and associated energizing coils,
and a magnetic ion beam transport system following the scanning system,
said transport system arranged to receive the beam from the scanning system over the range of two dimensional deflections of said scanning system and constructed to impose magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to a direction having a predetermined desired angular relationship with the axis in said two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of the beam over the substrate, and wherein said scanning system includes:
a first time-variable-field magnetic scanner for scanning the beam in the first dimension, and located axially downstream therefrom,
a second time-variable-field magnetic scanner magnetically uncoupled from said first scanner for scanning the beam in the second dimension,
the scanners effective at each instant to deflect the beam from said reference axis in a decoupled manner at respective angles in the respective dimensions that are determined by the desired instantaneous displacement of the beam on the substrate,
and wherein the gap of said second scanner diverges in the axial direction in manner and direction corresponding to the divergence of the deflection envelope produced by the first scanner, while the width (direction perpendicular to the gap) of the poles of said second magnetic scanner correspondingly increases progressively in the axial direction.

6 more elements

System for irradiating a surface of a substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions over the substrate, the system including:

an end station for presenting a substrate to the beam,
an ion source and associated beam-forming devices for producing a beam of atomic or molecular ions,
a magnetic scanning system for deflecting the beam in two dimensions relative to a reference axis, said system employing, for each dimensions of scan, a single scanning magnet means formed of a yoke and pole means of magnetic material and associated energizing coils,
and a magnetic ion beam transport system following the scanning system,
said transport system arranged to receive the beam from the scanning system over the range of two dimensional deflections of said scanning system and constructed to impose magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to a direction having a predetermined desired angular relationship with the axis in said two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of the beam over the substrate,
wherein scanner coils and associated magnetic circuits effective to generate fields to deflect the beam in decoupled manner in both dimensions are located in the same general vicinity along the beam path,
the magnetic scanning system comprising a circular iron yoke, a multiplicity of poles distributed about and extending inwardly toward the axis of said yoke, and respective, separate x and y dimension deflection coils associated with said poles, and
wherein the windings of the coils on the poles for the respective deflection directions vary in number according to the angular position of said poles relative to the respective deflection axis, and means to connect the respective sets of coils in series to be driven by a single, respective energization current for deflection in the respective dimension.

5 more elements

System for irradiating a surface of a substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions over the substrate, the system including:

an end station for presenting a substrate to the beam,
an ion source and associated beam-forming devices for producing a beam of atomic or molecular ions,
a magnetic scanning system for deflecting the beam in two dimensions relative to a reference axis, said system employing, for each dimension of scan, a single scanning magnet means formed of a yoke and pole means of magnetic material and associated energizing coils,
and a magnetic ion beam transport system following the scanning system,
said transport system arranged to receive the beam from the scanning system over the range of two dimensional deflections of said scanning system and constructed to impose magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to a direction having a predetermined desired angular relationship with the axis in said two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of the beam over the substrate,
wherein said ion beam transport system is an electromagnet system for establishing static magnetic fields capable of effecting a linear transformation of the two-dimensionally deflected beam such that the final position and angle at which the beam impinges on the target is a linear function of the angular direction and displacement of the beam entering the ion beam transport system.

3 more elements

System for irradiating a surface of a substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions over the substrate, the system including:

an end station for presenting a substrate to the beam,
an ion source and associated beam-forming devices for producing a beam of atomic or molecular ions,
a magnetic scanning system for deflecting the beam in two dimensions relative to a reference axis, said system employing, for each dimension of scan, a single scanning magnet means formed of a yoke and pole means of magnetic material and associated energizing coils,
and a magnetic ion beam transport system following the scanning system,
said transport system arranged to receive the beam from the scanning system over the range of two dimensional deflections of said scanning system and constructed to impose magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to a direction having a predetermined desired angular relationship with the axis in said two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, to produce the desired scan of the beam over the substrate, wherein said scanning system includes:
a first time-variable-field magnetic scanner for scanning the beam in the first dimension, and located axially downstream therefrom,
a second time-variable-field magnetic scanner magnetically uncoupled from said first scanner for scanning the beam in the second dimension,
the scanners effective at each instant to deflect the beam from said reference axis in a decoupled manner at respective angles in the respective dimensions that are determined by the desired instantaneous displacement of the beam on the substrate, and
wherein said ion beam transport system comprises multiple, axially spaced-apart static magnetic field-imposing elements constructed to enable accommodation of the different axial positions of said scanners while producing linear transformation of the deflected beam to the desired angular relationship and displacement of the beam.

6 more elements

System for irradiating a surface of a substrate with atomic or molecular ions by rapid scanning of a beam providing an ion-distributing beam spot in two dimensions over the substrate, the system including:

an end station for presenting a substrate to the beam,
an ion source and associated beam-forming devices for producing a beam of atomic or molecular ions,
a magnetic scanning system for deflecting the beam in two dimensions relative to a reference axis, said system employing, for each dimension of scan, a single scanning magnet means formed of a yoke and pole means of magnetic material and associated energizing coils,
and a magnetic ion beam transport system following the scanning system,
said transport system arranged to receive the beam from the scanning system over the range of two dimensional deflections of said scanning system and constructed to impose static magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected beam to a direction having a predetermined desired angular relationship with the axis in said two dimensions at the desired instantaneous two dimensional displacement of the beam from the axis, and produce the desired scan of an ion beam spot of ion-distributing size over the substrate, and
the system including a dynamic feedback control system including:
magnetic field detection means for detecting the magnetic fields of said scanning system and producing signals indicative of the fields affecting said beam during scanning of said ion beam;
and feedback control system for controlling the scanning system to produce a prescribed magnetic field profile in each of said two dimensions in a closed loop manner in response to said field detection means.

5 more elements

A magnetic scanning system constructed to deflect a beam of atomic or molecular ions in a first and second dimension relative to a reference axis, said system having a first and second time-variable-field magnetic scanners in first and second positions along the axis of the system for successively deflecting the beam in the respective dimensions, each magnetic scanner comprising a yoke and pole means of magnetic material and associated energizing coils, and each having a respective deflection circuit and power supply for applying time-varying current to said coils,

said first time-variable-field magnetic scanner having a magnetic gap through which the beam passes of volume smaller than the volume of the magnetic gap of said second scanner and being constructed to scan the beam in its respective dimension more rapidly than does the second scanner whereby the power requirement imposed by the higher frequency for the first scanner is ameliorated by the lower gap volume of said scanner, and
the scanners being effective at each instant to deflect the ion beam from said reference axis in a decoupled manner at respective angles in the respective dimensions that are determined by the desired instantaneous displacement of the ion beam.

An ion implantation system for doping a substrate by irradiating a surface of the substrate with atomic or molecular ions by rapid scanning of a beam in two dimensions, the beam providing an ion-distributing beam spot, the system including:

an end station for presenting a substrate to the ion beam,
a scanning system for deflecting the ion beam in two dimensions relative to a reference axis, and
a magnetic ion beam transport system following the scanning system, and preceding said end station, said transport system arranged to determine the angular relationship with which ions reach and are implanted into said substrate of said end station,
said magnetic transport system having multiple, axially spaced-apart static magnetic field-imposing elements constructed to impose static magnetic field conditions along the beam path of characteristics selected to reorient the two-dimensionally deflected ion beam to an implanting direction having a predetermined desired angular relationship with the axis in each of said two directions at the desired instantaneous two dimensional displacement of the ion beam from the axis, to produce the desired scan of the beam over the substrate.

1 more element

Dependencies are inferred from the claim text.

System for irradiating a surface with atomic and molecular ions using two dimensional magnetic scanning

Life of this patent

System for irradiating a surface with atomic and molecular ions using two dimensional magnetic scanning

Life of this patent

Abstract

Claims94