EP0396919A2
Expired / Lapsed
EP
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Plasma Reactor and method for semiconductor processing
Assignee: Applied Materials Inc
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Filing: 1990-04-09
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Granted: —
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Expires: 2010-04-09
Abstract
Abstract Magnetic confinement of electrons in a plasma reactor (200,300) is effected by using electro-magnetic coils (232,234,332,334) and other magnets (246) which generate respective magnetic fields (B,230) which are mutually opposed and substantially orthogonal on their common axis (236) to the major plane (242) of a wafer (202) being processed, instead of being aligned and parallel to the major plane as in prior magnetically enhanced plasma reactors. The respective magnetic fields (B,230) combine to yield a net magnetic field which is nearly parallel to the wafer (202) away from the magnetic axis (236) so that electrons are confined in the usual manner. In addition, a magnetic mirror (244) provides confinement near the magnetic axis (236). The E x B cross product defines a circumferential drift velocity urging electrons about a closed path about the magnetic axis (236). The magnetic and cross-product forces on plasma electrons have a rotational symmetry which enhances reaction uniformity across the wafer (202).
Inventors
- 👤 Peter R. Hanley
- 👤 Stephen E. Savas
- 👤 Karl B. Levy
- 👤 Neeta Jha
- 👤 Kevin Donohoe
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 18:44
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32623; H10; H10P; H10P95/00; H01J37/3266
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
74 words
A plasma reactor (200,300) for semiconductor processing comprising plasma generation means for forming a plasma (212) near a surface (242) of a semiconductor wafer (202), said plasma (212) being selected to promote predetermined reactions at said surface (242), characterized by confinement means (232,234,332,334,246) for magnetically confining said plasma (212), said confinement means defining a magnetic mirror region (244) which at least partially confines said plasma (212) to a region (222) near said wafer (202).
Claim 2
Dependent Claim
74 words
A plasma reactor (200,300) for semiconductor processing comprising plasma generation means for forming a plasma (212) near a surface (242) of a semiconductor wafer (202), said plasma (212) being selected to promote predetermined reactions at said surface (242), characterized by confinement means (232,234,332,334,246) for magnetically confining said plasma (212), said confinement means defining a magnetic mirror region (244) which at least partially confines said plasma (212) to a region (222) near said wafer (202).
Claim 3
Dependent Claim
29 words
The plasma reactor according to claim 1, characterized in that said confinement means (232,234,332,334,246) define an axi-symmetric magnetic field (B) with an axis (236) orthogonal to said surface (242).
Claim 4
Dependent Claim
72 words
The plasma reactor according to claim 1 or 2, characterized in that said confinement means include a first magnet (232,332) and a second magnet (234,334), said first magnet (232,332) providing a first magnetic field (230) with an axis (236) of symmetry orthogonal to said surface (242), said second magnet (234,334) providing a second magnetic field (B) sharing said axis (236) of symmetry and being axially opposed to said first magnetic field (230).
Claim 5
Dependent Claim
187 words
The plasma reactor according to claim 3, further comprising: a reaction vessel (204) defining a reaction chamber (206); gas introduction means (208) for introducing a reagent gas into said reaction chamber (206; exhaust handling means (210) for removing spent gases from said reaction chamber (206) and for maintaining a subambient pressure within said reaction chamber (206); support means (216,258,78) for supporting a semiconductor wafer (202) within said reaction chamber (206), said wafer (202) having a major surface (242) at which a reaction is to occur; power source means (218) for generating an oscillating electric field (E) to generate a plasma (212) from said reaction gas, said electric field (E) being generally orthogonal to said surface (242) so that positive ions of said plasma (212) are attracted to said surface (242); and confinement means (232,234,332,334,246) for generating a net magnetic field (B) which is axi-symmetric about an axis (236) orthogonal to said surface (242), said net magnetic field (B) including a magnetic mirror region (244) near said axis (236), said net magnetic field (B) being increasingly parallel to said surface (242) at increasing radii from said axis (236).
Claim 6
Dependent Claim
71 words
The plasma reactor of claim 4, characterized in that said plasma (212) has a sheath boundary (220) which is moved back and forth across a boundary space (222) by said plasma generation means (214,216,218) said first magnetic means (232,332) and said second magnet means (234,334) being cooperatively defined so that said net magnetic field (B) confines many of the more energetic electrons of said plasma (212) to said boundary space (222).
Claim 7
Dependent Claim
40 words
The plasma reactor according to any of preceding claims, characterized in that said confinement means includes a permanent magnet (246) within said support means (216), said permanent magnet (246) generating a field (B) which is axi-symmetric about said axis (236).
Claim 8
Dependent Claim
66 words
The plasma reactor according to any of preceding claims, characterized in that said plasma generation means (214,216,218) include means (218) for generating a radio frequency electric field (E); and said confinement means (232,234,332,334,246) define a magnetic field (B) which cooperates with said electric field (E) to induce plasma drift which is azimuthal about an axis (236) substantially orthogonal to said surface (242) of said wafer (202).
Claim 9
Dependent Claim
65 words
The plasma reactor according to claim 3, characterized in that said first magnet (232,332) being disposed on a first side of said major planar surface (242) such that said first magnetic axis (236) is substantially perpendicular thereto; and said second magnet (234,334) being disposed on a second side of said major planar surface (242) such that said second magnetic axis (236) is substantially perpendicular thereto.
Claim 10
Dependent Claim
37 words
The plasma reactor according to claim 8, characterized in that said first magnetic axis and said second magnetic axis (236) are substantially coaxial and are substantially centered on said major surface (242) of said semiconductor wafer (202).
Claim 11
Independent Claim
69 words
A method of confining a plasma (212) near a major surface (242) of a semiconductor wafer (202), said method comprising: disposing a magnetic mirror region (244) with a magnetic field gradient so that said gradient is substantially orthogonal to said surface (242) and so that said plasma (212) is at least partially confined between said surface (242) and said magnetic mirror region (244) and parallel to said surface (242).
Claim 12
Independent Claim
69 words
A method of confining a plasma (212) near a major surface (242) of a semiconductor wafer (202), said method comprising: disposing a magnetic mirror region (244) with a magnetic field gradient so that said gradient is substantially orthogonal to said surface (242) and so that said plasma (212) is at least partially confined between said surface (242) and said magnetic mirror region (244) and parallel to said surface (242).
Claim 13
Dependent Claim
31 words
The method according to claim 10, characterized in that confining said plasma (212) is using a magnetic field (B) which is axi-symmetric about an axis (236) orthogonal to said surface (242).
Claim 14
Dependent Claim
93 words
The method according to claim 11, characterized by the steps: - placing a semiconductor wafer (202) having a major planar surface (242) to be processed within a plasma environment (212) ; - forming a first magnetic field (230) on a first side of said major planar surface (242); and - forming a second magnetic field (B) on a second side of said major planar surface (242) such that said first magnetic field and said second magnetic field cooperate to trap energetic electrons of said plasma (212) proximate to said major planar surface (242).
Claim 15
Dependent Claim
24 words
The method according to claim 12, characterized in that said first magnetic field (230) and said second magnetic field (B) are of opposing polarities.
References Cited (Backward Citations)
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