Patent US6151349A successfully refreshed from Google Patents.
US6151349A
Expired / Lapsed
US
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Automatic fluorine control system
Assignee: Cymer LLC
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Filing: 1999-08-04
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Granted: 2000-11-21
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Expires: 2019-08-04
Abstract
Abstract An excimer laser system with an automatic fluorine control system to permit precise control of the fluorine concentration within an F 2 "sweet spot" in a gas discharge laser chamber. This is done with a computer control system which monitors laser parameters, determines ΔE/ΔV, the change of pulse energy with voltage, and automatically and precisely controls the fluorine concentration based on ΔE/ΔV without the need to actually measure the fluorine concentration.
Inventors
- 👤 Mengxiong Gong
- 👤 Jason R. Carlesi
- 👤 Michael C. Binder
- 👤 Palash P. Das
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:16
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/10; H01S3/02; H01S3/03; G; G03; G03F; G03F7/00; G03F7/70; G03F7/70008; G03F7/70025; G03F7/70041; G03F7/70216; G03F7/70358; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/70575; H01S3/036; H01S3/13; H01S3/131; H01S3/134; H01S3/14; H01S3/22; H01S3/223; H01S3/225; H01S3/05; H01S3/08; H01S3/08004; H01S3/08009; H01S3/2251; H01S3/2256
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
92 words
An excimer laser system comprising: A) a laser chamber containing: 1) two spaced apart elongated electrodes; 2) a laser gas comprising: a noble gas, fluorine, a buffer gas; B) a blower for flowing the laser gas between the two spaced apart electrodes; C) a fluorine source; D) a means for determining ΔE/ΔV; and E) a fluorine control system arranged to automatically control fluorine injection flow based on determined values of ΔE/ΔV in order to permit said laser to operate within a desired sweet spot determined by fluorine concentration in the laser chamber.
Claim 2
Dependent Claim
92 words
An excimer laser system comprising: A) a laser chamber containing: 1) two spaced apart elongated electrodes; 2) a laser gas comprising: a noble gas, fluorine, a buffer gas; B) a blower for flowing the laser gas between the two spaced apart electrodes; C) a fluorine source; D) a means for determining ΔE/ΔV; and E) a fluorine control system arranged to automatically control fluorine injection flow based on determined values of ΔE/ΔV in order to permit said laser to operate within a desired sweet spot determined by fluorine concentration in the laser chamber.
Claim 3
Dependent Claim
13 words
An excimer laser as in claim 1 wherein the noble gas is krypton.
Claim 4
Dependent Claim
13 words
An excimer laser as in claim 1 wherein the noble gas is argon.
Claim 5
Dependent Claim
41 words
An excimer laser as in claim 1 wherein krypton comprises about 1 percent of the laser gas fluorine comprises about 0.1 percent of the laser gas and the buffer gas is neon which comprises about 98.9 percent of the laser gas.
Claim 6
Dependent Claim
33 words
An excimer laser as in claim 1 wherein said feedback control system comprises temperature and pressure sensors and a processor programmed to adjust fluorine injection based on temperature deviations from a reference temperature.
Claim 7
Dependent Claim
29 words
An excimer laser as in claim 1 wherein said laser feedback control system is programmed to control fluorine flow to keep said laser operating within a predetermined sweet spot.
Claim 8
Dependent Claim
18 words
An excimer laser as in claim 6 wherein sweet spot is defined as a range of fluorine concentration.
Claim 9
Dependent Claim
24 words
An excimer laser as in claim 6 wherein said sweet spot is defined by a slope of a voltage vs. F 2 concentration curve.
Claim 10
Dependent Claim
47 words
An excimer laser as in claim 8 wherein said feedback control system is programmed to inject fluorine at intervals close enough together to simulate continuous injection in order to permit a voltage defined sweet spot no larger than about 2 percent of the nominal sweet spot voltage.
Claim 11
Dependent Claim
18 words
An excimer laser as in claim 8 and further comprising an exhaust line separate from said inject manifold.
Claim 12
Dependent Claim
20 words
An excimer laser as in claim 1 wherein said inject bottle has a gas volume of more than 0.5 liters.
Claim 13
Dependent Claim
21 words
An excimer laser as in claim 1 and further comprising a bleed bottle having a volume of more than 0.3 liters.
Claim 14
Dependent Claim
42 words
An excimer laser as in claim 1 and further comprising gas piping permitting gas flow from a relatively high pressure location of said chamber to said inject bottle and from said inject bottle to a relatively low pressure location of said chamber.
Claim 15
Dependent Claim
73 words
A process for controlling the fluorine concentration in a gas discharge laser comprising the steps of: A) operating the laser at various F 2 concentration levels and determining laser parameters to determine a preferred operating range; B) determine ΔE/ΔV within said preferred operating range; C) determine a ΔE/ΔV injection value, (ΔE/ΔV) i ; and D) during laser operation inject a quantity of F 2 when ΔE/ΔV decreases to or below (ΔE/ΔV) i .
Claim 16
Dependent Claim
73 words
A process for controlling the fluorine concentration in a gas discharge laser comprising the steps of: A) operating the laser at various F 2 concentration levels and determining laser parameters to determine a preferred operating range; B) determine ΔE/ΔV within said preferred operating range; C) determine a ΔE/ΔV injection value, (ΔE/ΔV) i ; and D) during laser operation inject a quantity of F 2 when ΔE/ΔV decreases to or below (ΔE/ΔV) i .
Claim 17
Dependent Claim
18 words
A process as in claim 14 wherein the quantity of F 2 injected is less than 5 milligrams.
Claim 18
Dependent Claim
24 words
A process as in claim 14 wherein said process is automatic and controlled by a computer processor programmed with a F 2 control algorithm.
References Cited (Backward Citations)
US6018537A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2003-11-21 | 2004-05-22 | 2004-11-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2007-11-21 | 2008-05-22 | 2008-11-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2011-11-21 | 2012-05-22 | 2012-11-21 | $7700.00 | Window Closed / Lapsed |