EP0451642A2
Expired / Lapsed
EP
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Sputtering system
Assignee: Applied Materials Inc
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Filing: 1991-03-28
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Granted: —
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Expires: 2011-03-28
Abstract
Abstract A sputtering system having a planar magnetron sputtering source (90) having a pair of pole pieces (91, 92) configured to produce a uniform coating, excellent step coverage and excellent step coverage uniformity of a wafer (42). Between the two pole pieces (91, 92) is a gap (912) within which the magnetic field and electric field produce an electron trap. The shape of the gap produces a depth of sputter profile (97, 98) in the target that results in the uniform coating, excellent step coverage and excellent step coverage uniformity. The outer pole piece is bowl-shaped in cross-section with a rim substantially coplanar with a planar inner pole piece.
Inventors
- 👤 Avi Tepman
- 👤 Norman William Parker
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 12:18
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/34; H01J37/3464; H01J37/347; H01J37/3402; H01J37/3405; H01J37/3408; H01J37/3411; H01J37/345; H01J37/3455
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
109 words
A sputtering system for sputtering particles from a target (41) onto a wafer (42), said sputtering system comprising: a reactor that encloses a vacuum chamber (1001) in which said target (41) and wafer (42) are to be placed; means (1004) for producing an electric field incident onto the target (41) to accelerate ions into the target to sputter particles from the target; means (90) for producing a sputtering intensity distribution in said target substantially equal to an ideal distribution S i (ρ t ) that produces a uniform thickness of sputtering particles on said wafer, where ρt is the distance of a point on the target from axis A.
Claim 2
Dependent Claim
157 words
A sputtering system as in claim 1 wherein said means (90) for producing a sputtering intensity distribution is a magnetron assembly comprising: a ferromagnetic inner pole piece (91, 1501); a ferromagnetic outer pole piece (92, 1502), that is coplanar with and encircles the inner pole piece (91, 1501) to produce between these two pole pieces a gap (912, 1505): a magnetic field source (93, 1503) that produces a magnetic field across the gap (912, 1505) between these two pole pieces; and a motor (95) that rotates these pole pieces at a common rotation rate about an axis A that is substantially perpendicular to a plane containing said pole pieces and on which said wafer (42) is to be centered perpendicular to this axis; said gap (912, 1505) having the shape of a closed loop for which the fraction of gap at each radial distance ρt from axis A is substantially equal to S i ( ρt ).
Claim 3
Dependent Claim
17 words
A sputtering system as in claim 2 wherein said gap (912, 1505) has a substantially constant width.
Claim 4
Dependent Claim
37 words
A sputtering system as in claim 2 or 3, wherein said pole pieces have been formed by milling into a sheet of ferromagnetic material a cut (1504) of width equal to the width of said gap (1505).
Claim 5
Dependent Claim
32 words
A sputtering system as in one of claims 2 to 4, wherein the said gap (912, 1505) intersects said rotation axis A, whereby the center of the wafer (42) is significantly sputtered.
Claim 6
Dependent Claim
44 words
A sputtering system as in one of claims 2 to 5, wherein the shape of said gap (912) consists of a plurality of arcs, preferably a set of four arcs, of substantially constant radius of curvature, connected in series to form a closed path.
Claim 7
Dependent Claim
60 words
A sputtering system as in claim 6, wherein a first of said arcs, of radius R₁ and arc length L, is substantially centered on axis A; and the other arcs are within the circle of radius R₁ about axis A, whereby a sputtered groove is formed in the target of depth proportional to the arc length of said first arc.
Claim 8
Dependent Claim
67 words
A sputtering system as in claim 7, wherein the first arc has a center point that is offset by a distance δ that is much smaller than R₁, whereby this arc has points that range in distance from the axis of rotation over the range from about R₁ - δ to R₁ + δ thereby widening an associated groove formed in the target by about 2 δ.
Claim 9
Dependent Claim
43 words
A sputtering system as in one of claims 6 to 8, wherein : each of the four arcs has an associated radius of curvature and these four radii are selected to optimize the uniformity of deposition of a sputtered coating on the wafer.
Claim 10
Dependent Claim
38 words
A sputtering system as in of the preceding claims, wherein the ratio of the target radius R t to the wafer R w is selected to optimise deposited coating thickness uniformity and/or step coverage uniformity over the wafer.
Claim 11
Dependent Claim
53 words
A sputtering system as in one of claims 2 to 10, wherein said ferromagnetic outer pole piece (1502) is bowl-shaped in cross-section and has a rim (1509) that is substantially coplanar with the inner pole piece (1501) and that encircles the inner pole piece to produce between these two pole pieces a gap.
Claim 12
Dependent Claim
34 words
A sputtering system as in claim 11, wherein the gap has the shape of a number three or of a pair of nonintersecting partial spirals that are connected at both ends of the spirals.
Claim 13
Dependent Claim
68 words
A sputtering system as in one of the preceding claims, wherein said means for producing a magnetic field across the gap comprises at least one rare earth magnet, whereby an increased effeciency of trapping is achieved and/or wherein said means for producing a magnetic field across the gap comprises at least one bar magnet, whereby an increase density of magnetic material is produced in between the pole pieces.
Claim 14
Dependent Claim
38 words
A sputtering system as in one of claims 11 to 13, further comprising a faceplate (1511) that is attached to the outer pole piece to produce a watertight enclosure about the means (1503) for producing a magnetic field.
References Cited (Backward Citations)
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