US3892940A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for uniformly heating monocrystalline wafers
Assignee: US Philips Corp
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Filing: 1973-06-27
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Granted: 1975-07-01
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Expires: 1993-06-27
Abstract
Abstract A plate-shaped susceptor for more uniformly heating monocrystalline wafers by high frequency induction wherein the susceptor is profiled on its lower side so that below the places destined for the wafers, the susceptor is thinner, resulting in less heat generation just below the central portion of the wafer to compensate for reduced heat radiation therefrom.
Inventors
- 👤 Jan Bloem
- 👤 Antonius Hermanus Goemans
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 07:54
CPC Classifications
C; C30; C30B; C30B25/00; C30B25/02; C30B25/12; C23; C23C; C23C16/00; C23C16/44; C23C16/458; C23C16/4582; C23C16/4583
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
127 words
A susceptor for heating to a uniform temperature in a high frequency field monocrystalline wafers of a selected geometrical shape and size, comprising a body having two opposed major surfaces, one major surface having spaced recesses of geometrical shape and size similar to the selected geometrical shape and size of said monocrystalline wafers, said recesses effectively decreasing the heat generated by said field in said body in the thinner regions between said recesses and the other major surface thereof, whereby wafers of said selected geometrical shape and size positioned on said other major surface and aligned with said recesses are heated less in the central areas thereof to compensate for reduced heat radiation from said areas resulting in a more substantially homogeneous temperature distribution in said wafers.
Claim 2
Dependent Claim
127 words
A susceptor for heating to a uniform temperature in a high frequency field monocrystalline wafers of a selected geometrical shape and size, comprising a body having two opposed major surfaces, one major surface having spaced recesses of geometrical shape and size similar to the selected geometrical shape and size of said monocrystalline wafers, said recesses effectively decreasing the heat generated by said field in said body in the thinner regions between said recesses and the other major surface thereof, whereby wafers of said selected geometrical shape and size positioned on said other major surface and aligned with said recesses are heated less in the central areas thereof to compensate for reduced heat radiation from said areas resulting in a more substantially homogeneous temperature distribution in said wafers.
Claim 3
Dependent Claim
24 words
A susceptor as defined in claim 1 wherein the depth of said recesses is no more than two thirds the thickness of said body.
Claim 4
Dependent Claim
24 words
A susceptor as defined in claim 2 wherein the depth of said recesses is no less than one third the thickness of said body.
Claim 5
Dependent Claim
23 words
A susceptor as defined in claim 3 wherein the depth of said recesses is at least twice the thickness of the selected wafers.
Claim 6
Dependent Claim
25 words
A susceptor as defined in claim 1 wherein the lateral dimensions of said recesses are no greater than the lateral dimensions of the selected wafers.
Claim 7
Dependent Claim
19 words
A susceptor as defined in claim 1 wherein said selected geometrical shape is circular and said recesses are circular.
Claim 8
Dependent Claim
30 words
A susceptor as defined in claim 6 wherein the diameter of said recesses is greater than one half and no more than equal to the diameter of the selected wafers.
Claim 9
Dependent Claim
43 words
A susceptor as defined in claim 1 wherein said thinner regions between said recesses and the other major surface of said body have a thickness no greater than four times the depth of penetration of the high frequency field in the body material.
Claim 10
Dependent Claim
30 words
A susceptor as defined in claim 8 wherein said thinner regions have a thickness of at least the depth of penetration of the high frequency field in the body material.
Claim 11
Dependent Claim
37 words
A susceptor as defined in claim 1 wherein said body has a thickness in regions other than said thinner regions of at least twice the depth of penetration of the high frequency field in the body material.
Claim 12
Dependent Claim
11 words
A susceptor as defined in claim 1 of material comprising graphite.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |