Patent CH290259A successfully refreshed from Google Patents.
Patent US4711989A successfully refreshed from Google Patents.
US4711989A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Diffusion furnace multizone temperature control
Assignee: Aviza Technology Inc
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Filing: 1986-05-19
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Granted: 1987-12-08
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Expires: 2006-05-19
Abstract
Abstract There is a substantial heat loss and drop in temperature in a hot-wall diffusion tube when a batch of wafers at room temperature is loaded into the tube. The temperature of the atmosphere in a zone in the tube is quickly recovered by sensing both the temperature of the tube atmosphere and the temperature of a heating element surrounding the zone with thermocouples, mixing the signals of the thermocouples to produce a ratio average signal and then controlling the heat input to the heating elements in response to the ratio average of the sensed temperature.
Inventors
- 👤 Chorng-Tao Yu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 04:48
CPC Classifications
C; C30; C30B; C30B31/00; C30B31/06; C30B31/12; C30B31/18
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
133 words
A method for recovering the atmospheric temperature in a multi-zone diffusion tube containing a freshly loaded batch of wafers, said tube having resistance heating elements disposed around its periphery, comprising the steps of: (a) providing at least one central zone between a load end zone and a source end zone; (b) loading a batch of wafers into the central zone; (c) heating the tube atmosphere toward a predetermined temperature; (d) sensing the temperature of a heating element in the central zone; (e) sensing the temperature of the tube atmosphere in the central zone; (f) controlling the heat input to the heating elements disposed around the central zone in response to a ratio average of the sensed temperatures of the heating element in the central zone and the tube atmosphere in the central zone.
Claim 2
Independent Claim
133 words
A method for recovering the atmospheric temperature in a multi-zone diffusion tube containing a freshly loaded batch of wafers, said tube having resistance heating elements disposed around its periphery, comprising the steps of: (a) providing at least one central zone between a load end zone and a source end zone; (b) loading a batch of wafers into the central zone; (c) heating the tube atmosphere toward a predetermined temperature; (d) sensing the temperature of a heating element in the central zone; (e) sensing the temperature of the tube atmosphere in the central zone; (f) controlling the heat input to the heating elements disposed around the central zone in response to a ratio average of the sensed temperatures of the heating element in the central zone and the tube atmosphere in the central zone.
Claim 3
Dependent Claim
81 words
The method of claim 1 comprising the additional steps of sensing the temperature of a heating element in each of the two end zones of the tube; and controlling the temperature in each end zone in response to the sensed temperature of the heating element in the end zone while the temperature of the central zone is controlled in response to a ratio average of the atmosphere temperature in the zone and the temperature of a heating element in the zone.
Claim 4
Dependent Claim
14 words
The method of claim 1 wherein the tube atmosphere is heated to about 600°.
Claim 5
Dependent Claim
15 words
The method of claim 1 wherein the tube atmosphere is heated to about 450° C.
Claim 6
Dependent Claim
15 words
The method of claim 1 wherein the tube atmosphere is heated to about 250° C.
Claim 7
Independent Claim
152 words
A method of controlling the temperature of the atmosphere in a semiconductor wafer diffusion tube having resistance heating elements disposed about its periphery, comprising the steps of: (a) providing at least one central zone between a load end zone and a source end zone; (b) loading a batch of wafers into the central zone; (c) heating the tube atmosphere toward a predetermined temperature; (d) sensing the temperature of a heating element in the central zone; (e) sensing the temperature of the tube atmosphere in the central zone; (f) controlling the heat input to the heating elements disposed around the central zone in response to a ratio average of the sensed temperatures of the heating element in the central zone and the tube atmosphere in the central zone; and (g) maintaining the temperature of the tube atmosphere in the central zone to within ±1° C. of the set point while processing the wafers.
Claim 8
Independent Claim
152 words
A method of controlling the temperature of the atmosphere in a semiconductor wafer diffusion tube having resistance heating elements disposed about its periphery, comprising the steps of: (a) providing at least one central zone between a load end zone and a source end zone; (b) loading a batch of wafers into the central zone; (c) heating the tube atmosphere toward a predetermined temperature; (d) sensing the temperature of a heating element in the central zone; (e) sensing the temperature of the tube atmosphere in the central zone; (f) controlling the heat input to the heating elements disposed around the central zone in response to a ratio average of the sensed temperatures of the heating element in the central zone and the tube atmosphere in the central zone; and (g) maintaining the temperature of the tube atmosphere in the central zone to within ±1° C. of the set point while processing the wafers.
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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) | 1990-12-07 | 1991-06-08 | 1991-12-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-07 | 1995-06-08 | 1995-12-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-07 | 1999-06-08 | 1999-12-08 | $7700.00 | Window Closed / Lapsed |