US4575922A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of fabricating integrated circuits incorporating steps to detect presence of gettering sites
Assignee: Unisys Corp
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Filing: 1984-11-05
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Granted: 1986-03-18
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Expires: 2004-11-05
Abstract
Abstract A method of fabricating integrated circuits on a semiconductor substrate includes the steps of directing electromagnetic radiation onto the semiconductor substrate at a small angular offset from the substrate's Bragg angle; measuring the intensity of the radiation that is reflected from the semiconductor substrate at the offset; and continuing with the fabrication of circuits on the substrate only if the measured intensity is substantially larger than the intensity which would reflect at the same angular offset from a defect-free crystal of the substrate material.
Inventors
- 👤 Michael H. Nemiroff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:10
CPC Classifications
G; G01; G01N; G01N23/00; G01N23/20; G01N23/207; H; H10; H10P; H10P36/00; H10P36/03
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
83 words
For use in fabricating integrated circuits on a semiconductor substrate, a method including the steps of: directing electromagnetic radiation onto said semiconductor substrate at a small angular offset from the substrate's Bragg angle; measuring the intensity of the radiation that is reflected from said semiconductor substrate at said offset; and fabricating said circuits on said semiconductor substrate only if the measured intensity is substantially larger than the intensity which would reflect at said angular offset from a defect-free crystal of said semiconductor substrate.
Claim 2
Dependent Claim
83 words
For use in fabricating integrated circuits on a semiconductor substrate, a method including the steps of: directing electromagnetic radiation onto said semiconductor substrate at a small angular offset from the substrate's Bragg angle; measuring the intensity of the radiation that is reflected from said semiconductor substrate at said offset; and fabricating said circuits on said semiconductor substrate only if the measured intensity is substantially larger than the intensity which would reflect at said angular offset from a defect-free crystal of said semiconductor substrate.
Claim 3
Dependent Claim
54 words
A method according to claim 1 and further including the steps of: generating gettering sites for mobile ions in said semiconductor substrate if said measured intensity is not substantially larger than that which would reflect from said defect-free crystal; and thereafter fabricating said circuits on said semiconductor substrate as modified with said gettering sites.
Claim 4
Dependent Claim
33 words
A method according to claim 1 and further including the step of: discarding said semiconductor substrate if said measured intensity is not substantially larger than that which would reflect from said defect-free crystal.
Claim 5
Dependent Claim
25 words
A method according to claim 1 wherein all of the recited steps are performed prior to the formation of any transistors on said semiconductor substrate.
Claim 6
Dependent Claim
25 words
A method according to claim 1 wherein all of the recited steps are performed after the formation of transistors on said semiconductor substrate has begun.
Claim 7
Dependent Claim
15 words
A method according to claim 1 wherein said angular offset is ten to forty minutes.
Claim 8
Dependent Claim
18 words
A method according to claim 1 wherein said radiation has a wavelength of 0.5 Å to 4 Å.
Claim 9
Dependent Claim
18 words
A method according to claim 1 wherein said semiconductor material is selected from silicon, germanium and gallium arsenide.
Claim 10
Dependent Claim
31 words
A method according to claim 1 wherein said fabricating step is performed only if said measured intensity is at least 25% larger than that which would reflect from said defect-free crystal.
Claim 11
Dependent Claim
80 words
In a process for fabricating integrated circuits on a semiconductor substrate, the substeps of: directing electromagnetic radiation onto said semiconductor substrate at a small angular offset of ten to forty minutes from the Bragg angle of said substrate; and continuing with the fabricating of said circuits on said semiconductor substrate only if at said angular offset, the radiation reflected therefrom exceeds by a predetermined amount the radiation which a defect-free crystal of said substrate would reflect at the same offset.
Claim 12
Dependent Claim
80 words
In a process for fabricating integrated circuits on a semiconductor substrate, the substeps of: directing electromagnetic radiation onto said semiconductor substrate at a small angular offset of ten to forty minutes from the Bragg angle of said substrate; and continuing with the fabricating of said circuits on said semiconductor substrate only if at said angular offset, the radiation reflected therefrom exceeds by a predetermined amount the radiation which a defect-free crystal of said substrate would reflect at the same offset.
Claim 13
Dependent Claim
37 words
A process according to claim 10 wherein the fabricating of said circuits is continued only if the radiation reflected from said semiconductor substrate is at least 25% larger than the radiation which said defect-free crystal would reflect.
Claim 14
Dependent Claim
66 words
A process according to claim 10 wherein the fabricating of said circuits is continued only if the maximum stress in said semiconductor substrate as calculated by S=SINθ B ÷SIN(θ B +Δθ)-1 exceeds a predetermined minimum value, where θ B is the Bragg angle and Δθ is the smallest angular offset from θ B at which the radiation from said semiconductor substrate and said defect-free crystal converge.
References Cited (Backward Citations)
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Cited
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US3984680A
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US4110625A
Cited
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-03-17 | 1989-09-16 | 1990-03-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-03-17 | 1993-09-16 | 1994-03-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-03-17 | 1997-09-16 | 1998-03-18 | $7700.00 | Window Closed / Lapsed |