US4468259A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Uniform wafer heating by controlling light source and circumferential heating of wafer
Assignee: Ushio Denki KK
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Filing: 1982-11-30
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Granted: 1984-08-28
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Expires: 2002-11-30
Abstract
Abstract When heating a semiconductor wafer by means of application of radiated light, it is effective to employ subsidiary heating means whose temperature rises upon exposure to the radiated light so that the circumferential portion of the wafer is additionally heated to compensate radiation of heat therefrom. The subsidiary heating means is arranged to elongate along the circumference of the wafer. It is important to limit the ratio of the characteristics, whose definition will be given below, of the subsidiary heating means to that of the wafer to 0.6-1.4 in order to avoid the occurrence of such a damage as slip line or the like in the wafer. The characteristics are expressed by the following formula: ##EQU1## wherein η: reflectivity; ρ: specific gravity (g/cm 3 ); d: thickness (cm); and C: specific heat (joule/g·°C.).
Inventors
- 👤 Yoshiki Mimura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 11:39
CPC Classifications
H; H10; H10P; H10P34/00; H10P34/40; H10P34/42; H10P34/422; Y; Y10; Y10S; Y10S148/00; Y10S148/09; Y10S148/093
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
148 words
A method for heating a semiconductor wafer by means of application of light radiated from a light source, the method comprising the steps of irradiating semiconductor wafer with a light radiated from the light source, including irradiating the circumferential portion of the semiconductor wafer, and additionally heating the circumferential portion of the semiconductor wafer with heat from a subsidiary heating means that extends along and adjacent to the circumference of the semiconductor wafer to thereby provide a uniform temperature across the surface of the wafer, the subsidiary heating means heated by the light energy from the light source, the ratio of a thermal characteristic of the subsidiary heating means to that of the semiconductor limited to a range between 0.6 and 1.4 said characteristics being expressed by the following formula: ##EQU8## wherein η: reflectivity; ρ: specific gravity (g/cm 3 ); d: thickness (cm); and C: specific heat (joule/g·°C.).
Claim 2
Independent Claim
148 words
A method for heating a semiconductor wafer by means of application of light radiated from a light source, the method comprising the steps of irradiating semiconductor wafer with a light radiated from the light source, including irradiating the circumferential portion of the semiconductor wafer, and additionally heating the circumferential portion of the semiconductor wafer with heat from a subsidiary heating means that extends along and adjacent to the circumference of the semiconductor wafer to thereby provide a uniform temperature across the surface of the wafer, the subsidiary heating means heated by the light energy from the light source, the ratio of a thermal characteristic of the subsidiary heating means to that of the semiconductor limited to a range between 0.6 and 1.4 said characteristics being expressed by the following formula: ##EQU8## wherein η: reflectivity; ρ: specific gravity (g/cm 3 ); d: thickness (cm); and C: specific heat (joule/g·°C.).
Claim 3
Dependent Claim
21 words
A method as claimed in claim 1, wherein the subsidiary heating means is a ring made of high fusing point metal.
Claim 4
Dependent Claim
20 words
A method as claimed in claim 2, wherein the subsidiary heating means has hooks which support the semiconductor wafer thereon.
Claim 5
Dependent Claim
45 words
A method as claimed in claim 1, wherein the light source comprises at least one plane light source the plane light source comprising a plurality of tubular halogen lamps arranged adjacent to one another in a plane parallel to the surface of the semiconductor wafer.
Claim 6
Dependent Claim
19 words
A method as claimed in claim 1, wherein the semiconductor wafer has been pretreated by the ion implantation process.
Claim 7
Dependent Claim
23 words
The method as claimed in claim 2, wherein the high fusing metal is selected from the group consisting of molybdenum, tungsten, or tantalum.
References Cited (Backward Citations)
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Cited
US3723053A
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JPS50427A
Cited
US4016006A
Cited
US4113547A
Cited
US4101759A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-08-28 | 1988-02-27 | 1988-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-28 | 1992-02-27 | 1992-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-28 | 1996-02-27 | 1996-08-28 | $7700.00 | Window Closed / Lapsed |