Active magnetic shielding
AssigneeApplied Materials, Inc.
InventorMark A. Perrin
Life of this patent
Estimating the term…
Abstract
Methods and apparatuses for shielding magnetic flux which is associated with a semiconductor fabrication system are provided. A magnetic shield assembly substantially surrounds a side wall of a plasma reactor. The shield assembly comprises a passive shield member in combination with an active shield member. As a result, effective shielding of magnetic flux can occur without excessive distortion of the magnetic field line pattern in the plasma region of the plasma reactor. In one aspect, the shield assembly comprises a first shield member adapted to attenuate a magnetic flux density. The first shield member is disposed in a parallel, spaced apart relationship from the side wall. A second member is attached to the first shield member and is constructed of a ferromagnetic material which is permanently magnetized.
Claims64
A shield assembly for a plasma reactor having a target and a semiconductor workpiece support facing said target along an axis, the shield assembly comprising:
- a first shield member constructed of a material which is adapted to attenuate a magnetic flux density, said first shield member being disposed so that at least a portion is in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said workpiece support;
- and
- a second member magnetically coupled with the first shield member, said second member being constructed of a ferromagnetic material which is permanently magnetized, said second member being disposed so that at least a portion is in the region located between the first and the second planes.
A shield assembly for a plasma reactor having a target and a semiconductor workpiece support facing said target along an axis, the shield assembly comprising:
- a first shield member constructed of a material which is adapted to attenuate a magnetic flux density, said first shield member being disposed so that at least a portion is in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said workpiece support;
- and
- a second member abutting the first shield member, said second member being constructed of a ferromagnetic material which is permanently magnetized, said second member being disposed so that at least a portion is in the region located between the first and the second planes.
A shield assembly for a plasma reactor having a semiconductor workpiece support and a target, said semiconductor workpiece support having a generally planar semiconductor workpiece support surface which is adapted to receive a semiconductor wafer and which defines a first imaginary plane, said target having a plurality of generally planar target surfaces which are generally parallel with the first plane, at least one of said target surfaces being disposed closest to the semiconductor workpiece support and defining a second imaginary plane, the shield assembly comprising:
- a first shield member constructed of a material which is adapted to attenuate a magnetic flux density, said first shield member being disposed so that at least a portion is in a region located between the first and the second planes;
- and
- a second member magnetically coupled with the first shield member, said second member being constructed of a ferromagnetic material which is permanently magnetized, said second member being disposed so that at least a portion is in the region located between the first and the second planes.
A shield assembly for a plasma reactor having a generally cylindrical side wall, the shield assembly comprising:
- a first shield member constructed of a material which is adapted to attenuate a magnetic flux density, said first shield member substantially surrounding the side wall;
- and
- a second member attached to the first shield member, said second member being constructed of a ferromagnetic material which is permanently magnetized.
A magnetic shield for a plasma reactor having a generally cylindrical side wall and having a generally cylindrical first shield member substantially surrounding the side wall, said first shield member constructed of a material which is adapted to attenuate a magnetic flux density, the magnetic shield comprising:
- a generally cylindrical second shield member adapted for attachment to the first shield member and for substantially surrounding the side wall, said second shield member being constructed of a ferromagnetic material which is permanently magnetized.
An apparatus for processing a semiconductor wafer, comprising:
- a target;
- a bottom wall;
- a side wall connected to the bottom wall, said bottom and side walls forming a cavity;
- a semiconductor workpiece support disposed in the cavity, said semiconductor workpiece support facing said target along an axis;
- a first shield member constructed of a material which is adapted to attenuate a magnetic flux density, said first shield member being disposed so that at least a portion is in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said workpiece support;
- and
- a second member abutting the first shield member, said second member being constructed of a ferromagnetic material which is permanently magnetized, said second member being disposed so that at least a portion is in the region located between the first and the second planes.
A method of depositing material on a semiconductor workpiece using a plasma reactor having a target and a semiconductor workpiece support facing said target along an axis, the method comprising:
- placing the semiconductor workpiece in a plasma reactor chamber;
- generating a plasma in the chamber;
- sputtering the material with the plasma in a plasma region to produce sputtered material particles;
- attenuating a magnetic flux density with a first shield member, at least a portion of which is disposed in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said workpiece support;
- and
- providing magnetic field lines from a second member into the plasma region, said second member being constructed of a ferromagnetic material which is permanently magnetized, said second member being disposed so that at least a portion is in the region located between the first and second planes.
A shield assembly for a plasma reactor having a target and semiconductor workpiece support facing said target along an axis, said plasma reactor further having a side wall which at least partially surrounds a plasma region, the shield assembly comprising:
- shielding means for attenuating a magnetic flux density, said shielding means being disposed so that at least a portion is in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said workpiece support;
- and
- means for providing magnetic field lines into the plasma region, said providing means comprising a ferromagnetic material which is permanently magnetized, said providing means being disposed so that at least a portion is in the region located between the first and second planes.
A magnetic shield for a plasma reactor having a target and semiconductor workpiece support facing said target along an axis, said plasma reactor further having a side wall which at least partially surrounds a plasma region and further having a shielding means for attenuating a magnetic flux density, said shielding means being disposed so that at least a portion is in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said workpiece support, the magnetic shield comprising:
- means for providing magnetic field lines into the plasma region, said providing means comprising a ferromagnetic material which is permanently magnetized, said providing means being disposed so that at least a portion is in the region located between the first and second planes.
An apparatus for using a plasma to process a semiconductor workpiece, comprising:
- a process chamber having a side wall which defines a cavity having a plasma region;
- a target;
- means for holding the workpiece in the cavity, said holding means facing said target along an axis;
- means for trapping electrons in the plasma region;
- shielding means for attenuating a magnetic flux density, said shielding means being disposed so that at least a portion is in a region located between first and second imaginary parallel planes located along said axis at axial locations between said target and said holding means;
- and
- means for providing magnetic field lines into the plasma region, said providing means being disposed so that at least a portion is in the region located between the first and second planes, said providing means comprising a ferromagnetic material which is permanently magnetized.
Dependencies are inferred from the claim text.