Patent US4472456A successfully refreshed from Google Patents.
US4472456A
Expired / Lapsed
US
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Absorption optimized laser annealing
Assignee: Texas Instruments Inc
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Filing: 1982-11-18
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Granted: 1984-09-18
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Expires: 2002-11-18
Abstract
Abstract A method for selectively heating an insulating layer on a semiconductor structure by a high energy transient radiation source to a temperature sufficient to cause reflow without any significant heating of the regions adjacent to or underlying the insulating layer. In one embodiment a laser tuned to the absorption wavelength of the insulating material is scanned over the surface of the semiconductor structure. In another embodiment an insulating layer and an underlying or adjacent semiconductor layer are concurrently heated by a laser tuned to an absorption wavelength common to both in order to maintain the integrity of the interface therebetween. In a further embodiment the depth of heating in an insulating layer is controlled by selecting an appropriate dwell time for a continuous wave laser and a pulse duration for a pulsed laser.
Inventors
- 👤 Rajiv R. Shah
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:51
CPC Classifications
H; H10; H10P; H10P95/00; H10P34/00; H10P34/40; H10P34/42; Y; Y10; Y10S; Y10S148/00; Y10S148/093; Y10S148/133
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
82 words
A method for selectively heating an insulating layer on a semiconductor device comprising the steps of: exposing the insulating layer to a continuous wave, scanned high energy laser beam, the wavelength of which is adjusted to coincide with a high absorption wavelength of said insulating layer; and selecting the dwell time of said laser beam so that the temperature rise in said insulating layer from said laser beam is substantially reduced as the distance from the surface of said insulating layer increases.
Claim 2
Independent Claim
82 words
A method for selectively heating an insulating layer on a semiconductor device comprising the steps of: exposing the insulating layer to a continuous wave, scanned high energy laser beam, the wavelength of which is adjusted to coincide with a high absorption wavelength of said insulating layer; and selecting the dwell time of said laser beam so that the temperature rise in said insulating layer from said laser beam is substantially reduced as the distance from the surface of said insulating layer increases.
Claim 3
Dependent Claim
12 words
The method of claim 1 wherein said insulating layer comprises phosphosilicate glass.
Claim 4
Dependent Claim
12 words
The method of claim 1 wherein said insulating layer comprises silicon dioxide.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein said insulating layer comprises silicon nitride.
Claim 6
Independent Claim
83 words
A method for selectively heating an insulating layer on a semiconductor device comprising the steps of: exposing the insulating layer to a pulsed, scanned high energy laser beam, the wavelength of which is adjusted to coincide with a high absorption wavelength of said insulating layer; and selecting the pulse duration and rate of said laser beam so that the temperature rise in said insulating layer from said laser beam is substantially reduced as the distance from the surface of said insulating layer increases.
Claim 7
Independent Claim
83 words
A method for selectively heating an insulating layer on a semiconductor device comprising the steps of: exposing the insulating layer to a pulsed, scanned high energy laser beam, the wavelength of which is adjusted to coincide with a high absorption wavelength of said insulating layer; and selecting the pulse duration and rate of said laser beam so that the temperature rise in said insulating layer from said laser beam is substantially reduced as the distance from the surface of said insulating layer increases.
Claim 8
Dependent Claim
12 words
The method of claim 5 wherein said insulating layer comprises phosphosilicate glass.
Claim 9
Dependent Claim
12 words
The method of claim 5 wherein said insulating layer comprises silicon dioxide.
Claim 10
Dependent Claim
12 words
The method of claim 5 wherein said insulating layer comprises silicon nitride.
Claim 11
Independent Claim
58 words
A method for fabricating a semiconductor device comprising the steps of: forming an insulating layer on a semiconductor region; exposing said insulating layer to high energy laser radiation which is coupled to said insulating layer and said underlying semiconductor layer to reflow said insulating layer while heating said semiconductor layer to maintain the integrity of the interface therebetween.
Claim 12
Independent Claim
58 words
A method for fabricating a semiconductor device comprising the steps of: forming an insulating layer on a semiconductor region; exposing said insulating layer to high energy laser radiation which is coupled to said insulating layer and said underlying semiconductor layer to reflow said insulating layer while heating said semiconductor layer to maintain the integrity of the interface therebetween.
Claim 13
Dependent Claim
49 words
The method of claim 9 wherein said exposing step comprises the steps of: adjusting the wavelength of said laser radiation to coincide with a high absorption wavelength of both said insulating layer and said semiconductor region; and continuously scanning a laser beam over the surface of said insulating layer.
Claim 14
Dependent Claim
19 words
The method of claim 10 wherein the scanning step is accomplished with a beam from a continuous wave laser.
Claim 15
Dependent Claim
18 words
The method of claim 11 wherein said insulating layer comprises phosphosilicate glass and said semiconductor region comprises silicon.
Claim 16
Dependent Claim
18 words
The method of claim 11 wherein said insulating layer comprises silicon dioxide and said semiconductor region comprises silicon.
Claim 17
Dependent Claim
18 words
The method of claim 10 wherein the scanning step is accomplished with a beam from a pulsed laser.
Claim 18
Dependent Claim
18 words
The method of claim 14 wherein said insulating layer comprises phosphosilicate glass and said semiconductor region comprises silicon.
Claim 19
Dependent Claim
18 words
The method of claim 14 wherein said insulating layer comprises silicon dioxide and said semiconductor region comprises silicon.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 1987-09-18 | 1988-03-19 | 1988-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-18 | 1992-03-19 | 1992-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-18 | 1996-03-19 | 1996-09-18 | $7700.00 | Window Closed / Lapsed |