US4865708A — Magnetron sputtering cathode

Claim 1

Independent Claim 164 words

A magnetron sputtering cathode consisting of target means and magnet means; said target means having a front surface, a body and a back surface; said magnet means having a front surface and a back surface, said magnetic means front surface being located adjacent to the back surface of said target and generating magnetic flux lines which form a closed-loop magnetic tunnel adjacent to said front surface of said target and within said target body; the curvature of said magnetic flux lines in the center of said tunnel changing progressively from concave, to flat, to convex with increasing distance from said magnet means; in the region where said magnetic flux lines are flat, the flat area is at least 20% of the width of said magnet means, is substantially parallel to said target, and is located substantially at said front surface of said target; and in the region where said magnetic flux lines are concave, said concave area is located substantially within said target body.

Claim 2

Dependent Claim 164 words

A magnetron sputtering cathode consisting of target means and magnet means; said target means having a front surface, a body and a back surface; said magnet means having a front surface and a back surface, said magnetic means front surface being located adjacent to the back surface of said target and generating magnetic flux lines which form a closed-loop magnetic tunnel adjacent to said front surface of said target and within said target body; the curvature of said magnetic flux lines in the center of said tunnel changing progressively from concave, to flat, to convex with increasing distance from said magnet means; in the region where said magnetic flux lines are flat, the flat area is at least 20% of the width of said magnet means, is substantially parallel to said target, and is located substantially at said front surface of said target; and in the region where said magnetic flux lines are concave, said concave area is located substantially within said target body.

Claim 3

Dependent Claim 65 words

A magnetron sputtering cathode as in claim 1; said magnetic means comprising two magnetic poles of opposite polarity, and a segment of magnetically permeable material disposed between said magnetic poles; said magnetic means forming a magnetically continuous loop along said tunnel and between said magnetic poles; and with the magnetomotive force developed at each of said magnetic poles being balanced with respect to each other.

Claim 4

Dependent Claim 93 words

A magnetron sputtering cathode as in claim 2; said target being a circular disc; said magnet poles each being two concentric rings of one or more permanent magnets; said rings magnetized in a direction perpendicular to said target; said inner and outer rings being magnetically polarized in opposite directions; a magnetically permeable pole piece being attached to said rings on said back surface of said magnet means; and an annular segment of magnetically permeable material disposed between said magnet poles, a gap existing between each of said magnet poles and said annular segment.

Claim 5

Dependent Claim 156 words

A magnetron sputtering cathode as in claim 2; said target being rectangular; said magnet means comprising permanent magnets with magnetization oriented, perpendicular to said target; said magnetic means including a linear center section and two end sections, in which said linear section is aligned along the length of said target; said linear section consisting of a plurality of magnets of one polarity orientation disposed along the edges of said magnetic means, and at least one magnet of the opposite polarity disposed behind the center of said target; all of said magnets attached to a magnetically permeable pole piece joining the poles on said back surface of said means magnet; said magnet means forming two parallel magnetic tunnels of opposite polarity, one on each side of the longitudinal centerline of the rectangular target; and two segments of magnetically permeable material disposed between said magnet poles, forming a gap between each of said poles and said permeable segments.

Claim 6

Dependent Claim 44 words

A magnetron sputtering cathode as in claim 4; said magnet means including two semicircular magnet end sections and two semicircular magnetically permeable segments disposed between said semicircular magnets, being joined or adjacent to said linear section so as to form a magnetically continuous structure.

Claim 7

Dependent Claim 79 words

A magnetron sputtering cathode as in claim 2; said target being circular; said magnet means comprising inner and outer concentric rings of one or more magnets, and magnetization in both of said rings oriented parallel to said target and parallel to the radii of said target; said rings magnetized along said radii to form a circular closed-loop magnetic tunnel; and an annular pole piece of magnetically permeable material disposed between said rings and in contact with said inner ring.

Claim 8

Dependent Claim 121 words

A magnetron sputtering cathode as in claim 2; said target being rectangular; said magnet means comprising a linear center section and two end sections, in which said linear section is aligned along the length of said target; said linear section including a plurality of permanent magnets with magnetization oriented parallel to said target and perpendicular to the longitudinal centerline of said target; a plurality of said magnets being on each side of said target centerline; said magnets on each side of said centerline magnetized in the same direction, and in the opposite direction to said magnets on the other side of said centerline; and at least one magnetically permeable segment on each side of said centerline and disposed between said magnets.

Claim 9

Dependent Claim 38 words

A magnetron sputtering cathode as in claim 2; said target being circular; said magnetic means comprising a plurally of concentric electromagnet coils, mounted in a magnetically permeable pole piece; and a magnetically permeable segment between the electromagnet poles.

Claim 10

Dependent Claim 24 words

A magnetron sputtering cathode as in claim 8; in which said magnetically permeable segment is a part of, or attached to, said pole piece.

Claim 11

Dependent Claim 20 words

A magnetron sputtering cathode as in claim 1; said magnet means including permanent magnets comprised of neodymium-iron-boron or samarium cobalt.

Claim 12

Dependent Claim 20 words

A magnetron sputtering cathode as in claim 1; said flat area being 40% of the width of said magnet means.

Claim 13

Independent Claim 159 words

A method of increasing the target utilization in a magnetron sputtering process wherein a glow discharge plasma is magnetically confined to a region adjacent to and above the target, said target having a front surface, a body and a back surface, comprising: utilizing magnetic means that generate magnetic flux lines which form a closed-loop magnetic tunnel adjacent to said front surface of said target and within said target body; the curvature of said magnetic flux lines in the center of said tunnel changing progressively from concave, to flat, to convex with increasing distance from said magnet means; in the region where said magnetic flux lines are flat, the flat area is at least 20% of the width of said magnet means, is substantially parallel to said target, and is located substantially at said front surface of said target; and in the region where said magnetic flux lines are concave, said concave area is located substantially within said target body

Claim 14

Independent Claim 159 words

A method of increasing the target utilization in a magnetron sputtering process wherein a glow discharge plasma is magnetically confined to a region adjacent to and above the target, said target having a front surface, a body and a back surface, comprising: utilizing magnetic means that generate magnetic flux lines which form a closed-loop magnetic tunnel adjacent to said front surface of said target and within said target body; the curvature of said magnetic flux lines in the center of said tunnel changing progressively from concave, to flat, to convex with increasing distance from said magnet means; in the region where said magnetic flux lines are flat, the flat area is at least 20% of the width of said magnet means, is substantially parallel to said target, and is located substantially at said front surface of said target; and in the region where said magnetic flux lines are concave, said concave area is located substantially within said target body

Claim 15

Dependent Claim 20 words

The method of claim 12, wherein said flat area is at least 40% of the width of said magnet means.

Claim 16

Dependent Claim 36 words

The method of claim 12, wherein said magnet means comprises a plurality of permanent magnets, a magnetically permeable pole piece attached to said permanent magnets and a magnetically permeable segment between some of said permanent magnets.

Claim 17

Dependent Claim 14 words

The method of claim 14, wherein said permanent magnets comprise neodymium-iron-boride or samarium cobalt.

Claim 18

Dependent Claim 18 words

The method of claim 14, wherein said magnet means is adjacent to said back surface of said target.

Claim 19

Dependent Claim 33 words

The method of claim 14, wherein said target means are rectangular and said magnet means consist of a linear portion and two semicircular portions attached at the two ends of said linear portions.

Claim 20

Dependent Claim 22 words

The method of claim 14, wherein said target is circular, and said magnet means consists of circularly shaped magnets and permeable segments.

Claim 21

Dependent Claim 27 words

The method of claim 12, wherein said magnet means comprise a plurality of electromagnetic coils, and a magnetically permeable segment between the poles of said magnet means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1992-09-11	1993-03-13	1993-09-12	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1996-09-11	1997-03-13	1997-09-12	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2000-09-11	2001-03-13	2001-09-12	$7700.00	Window Closed / Lapsed

Magnetron sputtering cathode

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