Patent US4632719A successfully refreshed from Google Patents.
US4632719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Semiconductor etching apparatus with magnetic array and vertical shield
Assignee: Novellus Systems Inc
•
Filing: 1985-09-18
•
Granted: 1986-12-30
•
Expires: 2005-09-18
Abstract
Abstract In an apparatus for etching a large semiconductor wafer the etch rate and uniformity of etching at the edges is improved by using an array of magnets behind the collector plate to form a double ring of plasma and using a grounded shield ring with perforations to pass gases. The shield ring extends both above and below the surface of the wafer being etched.
Inventors
- 👤 Robert Chow
- 👤 Steven D. Downey
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:23
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/32; H01J37/32431; H01J37/32623; H01J37/32651; H01J37/32009; H01J37/32082; H01J37/32642; H01J37/3266; H01J37/32669; H01J37/32715; H10; H10P; H10P72/00; H10P72/04; H10P72/0402; H10P72/0418; H10P72/0421
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
125 words
An apparatus for etching a face of a semiconductor wafer in an RF field comprising: a chamber capable of being substantially evacuated of atmospheric gases; means for introducing Argon gas into said chamber; a means for connecting said means for holding to a source of RF power; an electrical shield surrounding the wafer in said chamber, said shield being in close proximity to edge of the wafer and extending above and below the wafer; means for inducing a magnetic field in close proximity to the face of the wafer being etched, said means for inducing a magnetic field including means for forming at least two concentric coplanar rings of plasma between the surface of the wafer being etched and an opposing wall of said chamber.
Claim 2
Independent Claim
125 words
An apparatus for etching a face of a semiconductor wafer in an RF field comprising: a chamber capable of being substantially evacuated of atmospheric gases; means for introducing Argon gas into said chamber; a means for connecting said means for holding to a source of RF power; an electrical shield surrounding the wafer in said chamber, said shield being in close proximity to edge of the wafer and extending above and below the wafer; means for inducing a magnetic field in close proximity to the face of the wafer being etched, said means for inducing a magnetic field including means for forming at least two concentric coplanar rings of plasma between the surface of the wafer being etched and an opposing wall of said chamber.
Claim 3
Dependent Claim
26 words
An apparatus as in claim 1 wherein said electrical shield is formed of thin metal with perforations therein whereby to enhance the free flow of gas.
Claim 4
Dependent Claim
23 words
An apparatus as in claim 2 wherein said means for inducing a magnetic field includes a generally planar array of samarium-cobalt permanent magnets.
Claim 5
Dependent Claim
58 words
An apparatus as in claim 3 wherein said array of samarium-cobalt magnets are arranged as a central magnet, a first ring of magnets of polarity opposite said central magnet in a circle around said central magnet, and a second ring of magnets concentric with said first ring, said second ring having the same polarity as said central magnet.
Claim 6
Independent Claim
83 words
An apparatus for etching a face of a semiconductor wafer in an RF field, comprising: a means for isolating the wafer in a substantially pure atmosphere of low pressure Argon; a means for inducing a high voltage RF field on the wafer sufficient to ionize and accelerate Argon atoms toward the surface of the wafer being etched; and magnet means for forming a plasma into at least two concentric rings in a plane parallel and opposite the surface of the wafer being etched.
Claim 7
Independent Claim
83 words
An apparatus for etching a face of a semiconductor wafer in an RF field, comprising: a means for isolating the wafer in a substantially pure atmosphere of low pressure Argon; a means for inducing a high voltage RF field on the wafer sufficient to ionize and accelerate Argon atoms toward the surface of the wafer being etched; and magnet means for forming a plasma into at least two concentric rings in a plane parallel and opposite the surface of the wafer being etched.
Claim 8
Dependent Claim
58 words
An apparatus as in claim 5 wherein said magnet means includes a generally planar array of samarium-cobalt magnets arranged as a central magnet and two concentric rings of magnets of polarity alternating from said central magnet to an inner ring of said concentric rings and alternating again from said inner ring to an outer of said concentric rings.
Claim 9
Independent Claim
195 words
An apparatus for etching a face of a semiconductor wafer in an RF field, comprising: a means for holding a wafer, said means being connected to a source of RF power; a metal shield surrounding and in close proximity to the edge of the wafer, said shield extending above and below the wafer, said shield being electrically at polarity opposite said means for holding the wafer, said shield having formed therein a multiplicity of perforation whereby to enhance the passage of gas; chamber means for holding the wafer and said shield in a substantially pure atmosphere of Argon at low pressure, said chamber having a wall in close proximity to the face of the wafer being etched, and an array of magnets behind said wall of said chamber means which is in close proximity to the face of the wafer being etched, said magnets being arranged as a center magnet and rings of magnets concentric with said center, said center and said rings having alternately opposing polarity whereby to hold concentric rings of plasma between the face of the wafer being etched and said wall of said chamber means in close proximity to the wafer.
Claim 10
Independent Claim
195 words
An apparatus for etching a face of a semiconductor wafer in an RF field, comprising: a means for holding a wafer, said means being connected to a source of RF power; a metal shield surrounding and in close proximity to the edge of the wafer, said shield extending above and below the wafer, said shield being electrically at polarity opposite said means for holding the wafer, said shield having formed therein a multiplicity of perforation whereby to enhance the passage of gas; chamber means for holding the wafer and said shield in a substantially pure atmosphere of Argon at low pressure, said chamber having a wall in close proximity to the face of the wafer being etched, and an array of magnets behind said wall of said chamber means which is in close proximity to the face of the wafer being etched, said magnets being arranged as a center magnet and rings of magnets concentric with said center, said center and said rings having alternately opposing polarity whereby to hold concentric rings of plasma between the face of the wafer being etched and said wall of said chamber means in close proximity to the wafer.
References Cited (Backward Citations)
US3669861A
Cited
US3708418A
Cited
US4025410A
Cited
US4169031A
Cited
US4162954A
Cited
US4265729A
Cited
US4282083A
Cited
US4239611A
Cited
US4243505A
Cited
US4341616A
Cited
US4384933A
Cited
US4401539A
Cited
US4431473A
Cited
US4392932A
Cited
US4444643A
Cited
US4415427A
Cited
US4526643A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |