Patent US5522938A successfully refreshed from Google Patents.
US5522938A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Particle removal in supercritical liquids using single frequency acoustic waves
Assignee: Texas Instruments Inc
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Filing: 1994-08-08
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Granted: 1996-06-04
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Expires: 2014-08-08
Abstract
Abstract A method and apparatus for particle removal in supercritical fluids using a single frequency acoustic wave. A wafer (114) is placed in a process chamber (110) and cleaning gas is introduced through inlet port (116). The cleaning fluid is heated to at least the critical temperature of the cleaning fluid and may also be pressurized. A sonic wave is generated in process chamber (110) by sonic transducer (122) to create alternating bands of gas phase (G) and supercritical phase (SC) of the cleaning fluid. The sonic wave is preferably a traveling wave such that the gas (G) and supercritical (SC) phases move across the surface of wafer (114) removing contaminants from the wafer (114) and trapping them in the acoustic wave. The contaminants are then removed from the system with spent cleaning fluid through outlet port (118).
Inventors
- 👤 Sean O'Brien
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:41
CPC Classifications
B; B01; B01D; B01D21/00; B01D21/28; B01D21/283; B08; B08B; B08B3/00; B08B3/04; B08B3/10; B08B3/12; B08B7/00; B08B7/0021
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
99 words
A method for particle removal comprising the steps of: introducing a cleaning fluid to a process chamber; heating the cleaning fluid to at least the critical temperature of the cleaning fluid; and generating a single frequency acoustic wave in a process chamber wherein said step of generating said single frequency acoustic wave creates a plurality of gas phase regions, a plurality of supercritical phase regions, and a plurality of interface regions between each gas phase region and each supercritical phase region, said pluralities of gas phase regions, supercritical phase regions and interface regions existing simultaneously in said process chamber.
Claim 2
Independent Claim
99 words
A method for particle removal comprising the steps of: introducing a cleaning fluid to a process chamber; heating the cleaning fluid to at least the critical temperature of the cleaning fluid; and generating a single frequency acoustic wave in a process chamber wherein said step of generating said single frequency acoustic wave creates a plurality of gas phase regions, a plurality of supercritical phase regions, and a plurality of interface regions between each gas phase region and each supercritical phase region, said pluralities of gas phase regions, supercritical phase regions and interface regions existing simultaneously in said process chamber.
Claim 3
Dependent Claim
29 words
The method of claim 1, further comprising the step of pressurizing said cleaning fluid to a pressure on between zero and twice the critical pressure of the cleaning fluid.
Claim 4
Dependent Claim
21 words
The method of claim 1, wherein said introducing a cleaning fluid step continuously introduces cleaning fluid and removes used cleaning fluid.
Claim 5
Dependent Claim
26 words
The method of claim 1, wherein said step of generating said single frequency acoustic wave comprises the step of generating a single frequency traveling acoustic wave.
Claim 6
Dependent Claim
29 words
The method of claim 1, further comprising the step of moving a wafer through said single frequency acoustic wave, wherein said single frequency acoustic wave is a standing wave.
Claim 7
Dependent Claim
24 words
The method of claim 1, wherein said single frequency acoustic wave has an intensity less than twice the critical pressure of the cleaning fluid.
Claim 8
Dependent Claim
20 words
The method of claim 1, wherein said single frequency acoustic wave is generated parallel to the surface of a wafer.
Claim 9
Independent Claim
80 words
A method for wafer cleaning, comprising the steps of: a. placing a wafer in a process chamber; b. introducing a cleaning fluid to said process chamber; c. heating said cleaning fluid to at least the critical temperature of said cleaning fluid; and d. generating a sonic wave in said process chamber such that a maximum pressure is greater than the critical pressure of the cleaning fluid and a minimum pressure is less than the critical pressure of the cleaning fluid.
Claim 10
Independent Claim
80 words
A method for wafer cleaning, comprising the steps of: a. placing a wafer in a process chamber; b. introducing a cleaning fluid to said process chamber; c. heating said cleaning fluid to at least the critical temperature of said cleaning fluid; and d. generating a sonic wave in said process chamber such that a maximum pressure is greater than the critical pressure of the cleaning fluid and a minimum pressure is less than the critical pressure of the cleaning fluid.
Claim 11
Dependent Claim
28 words
The method of claim 8, further comprising the step of pressurizing said cleaning fluid to a pressure on the order of the critical pressure of said cleaning fluid.
Claim 12
Dependent Claim
13 words
The method of claim 8, wherein said sonic wave is a traveling wave.
Claim 13
Dependent Claim
25 words
The method of claim 8, further comprising the step of moving said wafer through said sonic wave, wherein said sonic wave is a standing wave.
Claim 14
Dependent Claim
29 words
The method of claim 8, wherein a plurality of contaminants from the surface of the wafer become trapped in said sonic wave and are removed from the process chamber.
References Cited (Backward Citations)
US4836684A
Cited
US5013366A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-06-04 | 1999-12-04 | 2000-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-06-04 | 2003-12-04 | 2004-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-06-04 | 2007-12-04 | 2008-06-04 | $7700.00 | Window Closed / Lapsed |