US5835520A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Very narrow band KrF laser
Assignee: Cymer LLC
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Filing: 1997-04-23
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Granted: 1998-11-10
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Expires: 2017-04-23
Abstract
Abstract A very narrow band KrF excimer laser capable of producing 10 mJ laser pulses at 1000 Hz with a bandwidth of less than 0.6 nm (FWHM). The very narrow bandwidth is achieved by reducing fluorine partial pressure to less than 0.08 and by increasing the reflectance of the output coupler to greater than 25 percent. In a preferred embodiment, prior art fused silica beam expansion prisms used in the prior art line narrowing module were replaced with calcium fluoride prisms.
Inventors
- 👤 Palash Parijat Das
- 👤 Alexander I. Ershov
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:58
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70008; G03F7/70025; G03F7/70041; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/70575; H; H01; H01S; H01S3/00; H01S3/02; H01S3/03; H01S3/14; H01S3/22; H01S3/223; H01S3/225; H01S3/05; H01S3/08; H01S3/08004; H01S3/08009; H01S3/081; H01S3/0811; H01S3/0812; H01S3/09; H01S3/097; H01S3/0971; H01S3/09713; H01S3/2251; H01S3/2256
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
95 words
A very narrow band KrF excimer laser comprising: A. a laser chamber comprised of fluorine compatible materials and containing: (1) two elongated electrodes; (2) at least one preionizer; (3) laser gas defining a total pressure and comprised of krypton, fluorine and a buffer gas, said fluorine having a partial pressure of less than 0.08 of the total pressure; B. a line narrowing module comprised of: (1) at least one beam expanding prism; (2) a grating; (3) a tuning means for tuning the grating; and C. an output coupler having a reflectance of at least 25%.
Claim 2
Dependent Claim
95 words
A very narrow band KrF excimer laser comprising: A. a laser chamber comprised of fluorine compatible materials and containing: (1) two elongated electrodes; (2) at least one preionizer; (3) laser gas defining a total pressure and comprised of krypton, fluorine and a buffer gas, said fluorine having a partial pressure of less than 0.08 of the total pressure; B. a line narrowing module comprised of: (1) at least one beam expanding prism; (2) a grating; (3) a tuning means for tuning the grating; and C. an output coupler having a reflectance of at least 25%.
Claim 3
Dependent Claim
21 words
A very narrow band excimer laser as in claim 1 wherein said at least one prism is comprised of calcium fluoride.
Claim 4
Dependent Claim
23 words
A very narrow band excimer laser as in claim 1 wherein at least one prism is three prisms, all comprised of calcium fluoride.
Claim 5
Dependent Claim
26 words
A very narrow band excimer laser as in claim 1 wherein the partial pressure of fluorine is less than 0.06 percent of the total gas pressure.
References Cited (Backward Citations)
US5559816A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-11-09 | 2002-05-11 | 2002-11-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-11-09 | 2006-05-11 | 2006-11-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-11-09 | 2010-05-11 | 2010-11-10 | $7700.00 | Window Closed / Lapsed |