US4526534A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cantilever diffusion tube apparatus and method
Assignee: Amtech Systems Inc
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Filing: 1984-04-09
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Granted: 1985-07-02
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Expires: 2004-04-09
Abstract
Abstract A cantilever diffusion tube apparatus includes a quartz cantilever tube having a support end clamped to a laterally movable carriage mechanism and an outer end portion containing a plurality of spaced semiconductor wafers. The cantilever tube is coaxially aligned with a diffusion tube of a diffusion furnace. The support end of the cantilever tube is sealed by a door plate through which a gas tube extends. The wafers are loaded into the cantilever tube through a window opening. The carriage then moves the cantilever tube and wafers therein into the diffusion tube. Reactant gases are caused to flow into the cantilever tube, between the heated wafers therein, and out of the cantilever tube. Then purging gas is caused to flow through the cantilever tube and wafers therein. Withdrawal of the cantilever tube from the diffusion tube is then performed as the purging gas flow continues, avoiding excessive thermal shock, premature exposure of wafers to ambient oxygen and exposure of the wafers to air containing defect-causing particles. The cantilever tube, when contaminated after a number of runs, is easily exchanged for a clean one, avoiding the need for frequent cleaning of the diffusion tube.
Inventors
- 👤 Andrew F. Wollmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 03:21
CPC Classifications
F; F27; F27B; F27B5/00; F27B5/06; F27B5/12; F27B5/02; F27D; F27D5/00
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
233 words
A method of processing a plurality of semiconductor wafers in a furnace, said method comprising the steps of: (a) holding a rigid, heat-resistant first tube having a first end and a second end in a cantilever manner by said first end thereof; (b) placing said plurality of wafers in spaced relationship to each other inside said first tube; (c) causing a first gas to flow into said first tube between said wafers and out of said first tube; (d) moving said first tube with said wafers therein into a rigid, heat-resistant second tube that is located in said furnace to position said plurality of wafers in a hot zone of said furnace while said first gas is flowing between said wafers; (e) stopping the flow of said first gas into said first tube; (f) causing a reactant gas to flow into said first tube, between said wafers in said hot zone, and out of said first tube; (g) stopping the flow of said reactant gas into said first tube after the elapsing of a predetermined amount of time; (h) causing a second gas to flow into said first tube, between said plurality of wafers, and out of said first tube; (i) moving said first tube and said wafers therein out of said second tube while continuing said flow of said second gas; and (j) removing said plurality of wafers from said first tube.
Claim 2
Independent Claim
233 words
A method of processing a plurality of semiconductor wafers in a furnace, said method comprising the steps of: (a) holding a rigid, heat-resistant first tube having a first end and a second end in a cantilever manner by said first end thereof; (b) placing said plurality of wafers in spaced relationship to each other inside said first tube; (c) causing a first gas to flow into said first tube between said wafers and out of said first tube; (d) moving said first tube with said wafers therein into a rigid, heat-resistant second tube that is located in said furnace to position said plurality of wafers in a hot zone of said furnace while said first gas is flowing between said wafers; (e) stopping the flow of said first gas into said first tube; (f) causing a reactant gas to flow into said first tube, between said wafers in said hot zone, and out of said first tube; (g) stopping the flow of said reactant gas into said first tube after the elapsing of a predetermined amount of time; (h) causing a second gas to flow into said first tube, between said plurality of wafers, and out of said first tube; (i) moving said first tube and said wafers therein out of said second tube while continuing said flow of said second gas; and (j) removing said plurality of wafers from said first tube.
Claim 3
Dependent Claim
21 words
The method of claim 1 including allowing the temperature of said wafers to stabilize in said hot zone before step (e).
Claim 4
Dependent Claim
58 words
The method of claim 1 wherein said first tube has an annular flange attached to the first end thereof and said holding step includes clamping said annular flange toward a support plate to effectuate holding of the entire weight of said first tube and said wafers therein by means of said annular flange during steps (d) and (b).
Claim 5
Dependent Claim
35 words
The method of claim 1 wherein said first tube has a window opening in a distal end portion thereof, said method including a cover over said window opening after step (b) but before step (d).
Claim 6
Dependent Claim
32 words
The method of claim 3 including sealing said annular flange with respect to an annular flange attached to a first end of said second tube during a final portion of step (d).
Claim 7
Dependent Claim
31 words
The method of claim 3 wherein step (d) is performed by means of a motorized mechanism coupled to a carriage supporting the means clamping said annular flange of said first tube.
Claim 8
Dependent Claim
49 words
The method of claim 5 wherein the reactant gas flows into said first tube through an opening in a cover plate clamped to said first end of said first tube, and flows out of an opening in the second end of said first tube and into said second tube.
Claim 9
Dependent Claim
56 words
The method of claim 5 wherein the reactant gas flows into an opening at a pigtail end of said second tube and into said second tube and then into an opening at the second end of said first tube and out of said first tube through an opening in said first end of said first tube.
Claim 10
Dependent Claim
25 words
The method of claim 3 including engaging said annular flange by means of a clamping mechanism attached to a carriage which moves on a track.
Claim 11
Dependent Claim
16 words
The method of claim 1 wherein both said first gas and said second gas are nitrogen.
Claim 12
Dependent Claim
17 words
The method of claim 1 wherein said moving of step (i) is approximately 9 inches per minute.
Claim 13
Dependent Claim
26 words
The method of claim 1 wherein said first tube is composed of material of one of the group consisting of quartz, silicon carbide, and polycrystalline silicon.
Claim 14
Dependent Claim
24 words
The method of claim 10 wherein the flow rate of said second gas through said first tube is approximately 100 cubic centimeters per minute.
Claim 15
Independent Claim
205 words
A method of processing a plurality of semiconductor wafers in a furnace, said method comprising the steps of: (a) holding a rigid, heat-resistant tube having a first end and a second end in a cantilever manner by said first end thereof; (b) placing said plurality of wafers in spaced relationship to each other inside said tube; (c) causing a first gas to flow into said tube between said wafers and out of said tube; (d) moving said tube with said wafers therein into said furnace to position said plurality of wafers in a hot zone of said furnace; (e) stopping the flow of said first gas into said tube; (f) causing a reactant gas to flow into said tube, between said wafers in said hot zone, and out of said tube; (g) stopping the flow of said reactant gas into said tube after the elapsing of a predetermined amount of time; (h) causing a second gas to flow into said tube, between said plurality of wafers, and out of said tube; (i) moving said tube and said wafers therein out of said hot zone of said furnace while continuing said flow of said second gas; and (j) removing said plurality of wafers from said tube.
Claim 16
Independent Claim
205 words
A method of processing a plurality of semiconductor wafers in a furnace, said method comprising the steps of: (a) holding a rigid, heat-resistant tube having a first end and a second end in a cantilever manner by said first end thereof; (b) placing said plurality of wafers in spaced relationship to each other inside said tube; (c) causing a first gas to flow into said tube between said wafers and out of said tube; (d) moving said tube with said wafers therein into said furnace to position said plurality of wafers in a hot zone of said furnace; (e) stopping the flow of said first gas into said tube; (f) causing a reactant gas to flow into said tube, between said wafers in said hot zone, and out of said tube; (g) stopping the flow of said reactant gas into said tube after the elapsing of a predetermined amount of time; (h) causing a second gas to flow into said tube, between said plurality of wafers, and out of said tube; (i) moving said tube and said wafers therein out of said hot zone of said furnace while continuing said flow of said second gas; and (j) removing said plurality of wafers from said tube.
References Cited (Backward Citations)
US4351805A
Cited
US4412812A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-07-01 | 1988-12-31 | 1989-07-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-07-01 | 1992-12-31 | 1993-07-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-07-01 | 1996-12-31 | 1997-07-02 | $7700.00 | Window Closed / Lapsed |