High-density plasma for ionized metal deposition capable of exciting a plasma wave
First Claim
1. A magnetron assembly positionable at a backside of a sputtering target and rotatable about a center position of said target, comprising a single magnetron asymmetrically disposed about said center position and including:
- a first pole of a first magnetic polarity comprising first magnets of a first magnetic polarity arranged in a triangular shape, at least two of said first magnets being bar magnets arranged on long sides of said triangular shape and being inclined to each other by between 10° and
35°
; and
a second pole of a second magnetic polarity disposed inside of said triangular shape and separated from said first magnets by a gap extending along a surface of said target.
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Accused Products
Abstract
A magnetron especially advantageous for low-pressure plasma sputtering or sustained self-sputtering having reduced area but full target coverage. The magnetron includes an outer pole face surrounding an inner pole face with a gap therebetween. The outer pole of the magnetron of the invention is smaller than that of a circular magnetron similarly extending from the center to the periphery of the target. A preferred triangular shape having a small apex angle of 20 to 30° may be formed from outer bar magnets of one magnetic polarity enclosing an inner magnet of the other magnetic polarity. The magnetron allows the generation of plasma waves in the neighborhood of 22 MHz which interact with the 1 to 20 eV electrons of the plasma to thereby increase the plasma density.
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Citations
22 Claims
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1. A magnetron assembly positionable at a backside of a sputtering target and rotatable about a center position of said target, comprising a single magnetron asymmetrically disposed about said center position and including:
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a first pole of a first magnetic polarity comprising first magnets of a first magnetic polarity arranged in a triangular shape, at least two of said first magnets being bar magnets arranged on long sides of said triangular shape and being inclined to each other by between 10° and
35°
; and
a second pole of a second magnetic polarity disposed inside of said triangular shape and separated from said first magnets by a gap extending along a surface of said target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A DC plasma sputter reactor, comprising:
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a vacuum chamber having a substantially circular target with a substantially planar central portion facing a substrate to be sputter coated;
a DC power supply negatively biasing said target with respect to said chamber;
a magnetron comprising a first pole of a first magnetic polarity substantially enclosing a second pole of a second magnetic polarity, said first and second poles being rotatable as a unit about a center of said target, said magnetron being disposed on a side of said target opposite said substrate;
wherein a level of power supplied by said DC power supply to said target is sufficiently high to generate a first plasma wave that is converted into a second plasma wave having a frequency between 5 and 75 MHz. - View Dependent Claims (14, 15, 16)
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17. A method of sputtering, comprising the steps of:
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providing a sputtering target having a planar central portion sealed to a plasma reaction chamber;
rotating a magnetron about a center of said target, said magnetron having an inner pole of one magnetic polarity surrounded by a magnetically stronger outer pole of a second magnetic polarity;
DC biasing said sputtering target with respect to chamber to create a plasma within said chamber to thereby sputter said target, said DC biasing being sufficiently strong to launch a first plasma wave of a first frequency;
converting said first plasma wave to a second plasma wave of a second frequency of less than 20% of said first frequency; and
interacting said second plasma wave with electrons of said plasma. - View Dependent Claims (18, 19, 20, 21)
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22. A DC plasma sputter reactor, comprising:
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a vacuum chamber having a substantially circular target with a substantially planar central portion facing a substrate to be sputter coated;
a DC power supply negatively biasing said target with respect to said chamber;
an unbalanced magnetron comprising a first pole of a first magnetic polarity substantially enclosing a second pole of a second magnetic polarity, a total magnetic flux of said first pole being at least 150% of a magnetic flux of said second pole, said second pole having no aperture therein, said first and second poles being rotatable as a unit about a center of said target, said magnetron being disposed on a side of said target opposite said substrate and rotating about a center thereof;
wherein a level of power supplied by said DC power supply to said target is sufficiently high and said unbalanced magnetron produces a magnetic configuration with a sufficient magnetic strength to generate a first plasma wave that is converted into a second plasma wave having a frequency between 5 and 75 MHz.
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Specification