US6327290B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Beam delivery system for molecular fluorine (F2) laser
Assignee: Lambda Physik AG
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Filing: 2000-06-14
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Granted: 2001-12-04
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Expires: 2020-06-14
Abstract
Abstract A system is provided for delivering a laser beam of wavelength less than 200 nm from a laser, such as an F 2 laser or ArF laser, through a sealed enclosure sealably connected to the laser, and preferably to another housing, leading ultimately to a workpiece. The enclosure is preferably evacuated and back-filled with an inert gas to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter or alternatively, an inert gas flow is established and maintained within the enclosure during operation of the laser. The inert gas preferably has high purity, e.g., more than 99.5% and preferably more than 99.999%, wherein the inert is preferably nitrogen or a noble gas. The enclosure is preferably sealed by a window transparent to the sub-200 nm radiation for preventing contaminants generated in the enclosure from entering the housing and contaminating surfaces therein. The enclosure is preferably made of steel and/or copper, and the window is preferably made of CaF 2 .
Inventors
- 👤 Sergei V. Govorkov
- 👤 Klaus Wolfgang Vogler
- 👤 Frank Voss
- 👤 Rainer Pätzel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:35
CPC Classifications
H; H01; H01S; H01S3/00; H01S3/14; H01S3/22; H01S3/223; H01S3/225; B; B23; B23K; B23K26/00; B23K26/12; B23K26/127; B23K26/128; B23K26/70; B23K26/702; B23K26/705; G; G01; G01J; G01J1/00; G01J1/42; G01J1/4257; G03; G03F; G03F7/00; G03F7/70; G03F7/70008; G03F7/70025; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/708; G03F7/70808; B23K2103/00; B23K2103/02; B23K2103/04; B23K2103/05; H01S3/0014; H01S3/10; H01S3/13; H01S3/131; H01S3/134
Claims Analysis
Total Claims: 39
Claim 1
Independent Claim
200 words
A laser system including a VUV laser emitting at a wavelength of less than 200 nm for generating and delivering a VUV laser beam to a workpiece, comprising: a discharge chamber filled with a laser active medium; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the laser active medium; a resonator including the discharge chamber for generating said VUV laser beam having a wavelength less than 200 nm; and an enclosure separating at least a portion of the beam path exiting the laser from the outer atmosphere and having a plurality of ports for evacuating the enclosure and flowing an inert gas within said enclosure after evacuating said enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can reach the workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path; and a window sealing the enclosure, wherein the window is substantially transparent at said emission wavelength less than 200 nm to allow the beam to exit the enclosure, while preventing contaminants generated within the enclosure from exiting the enclosure and contaminating surfaces outside of the enclosure.
Claim 2
Dependent Claim
200 words
A laser system including a VUV laser emitting at a wavelength of less than 200 nm for generating and delivering a VUV laser beam to a workpiece, comprising: a discharge chamber filled with a laser active medium; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the laser active medium; a resonator including the discharge chamber for generating said VUV laser beam having a wavelength less than 200 nm; and an enclosure separating at least a portion of the beam path exiting the laser from the outer atmosphere and having a plurality of ports for evacuating the enclosure and flowing an inert gas within said enclosure after evacuating said enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can reach the workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path; and a window sealing the enclosure, wherein the window is substantially transparent at said emission wavelength less than 200 nm to allow the beam to exit the enclosure, while preventing contaminants generated within the enclosure from exiting the enclosure and contaminating surfaces outside of the enclosure.
Claim 3
Dependent Claim
37 words
The system of claim 1 , wherein the window comprises a material selected from the group of materials consisting of CaF 2 , BaF 2 , SrF 2 , MgF 2 , LiF, quartz and fluorine-doped quartz.
Claim 4
Dependent Claim
13 words
The system of claim 1 , wherein the window comprises CaF 2 .
Claim 5
Dependent Claim
27 words
The system of claim 1 , wherein said window is disposed between said enclosure and an external housing of an optical imaging apparatus of a photolithography system.
Claim 6
Dependent Claim
151 words
A laser system including a VUV laser emitting at a wavelength of less than 200 nm for generating and delivering a VUV laser beam to a workpiece, comprising: a discharge chamber filled with a laser active medium; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the laser active medium; a resonator including the discharge chamber for generating said VUV laser beam having a wavelength less than 200 nm; and an enclosure separating at least a portion of the beam path exiting the laser from the outer atmosphere and having a plurality of ports for flowing an inert gas of greater than 99.5% purity within said enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can reach the workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 7
Dependent Claim
151 words
A laser system including a VUV laser emitting at a wavelength of less than 200 nm for generating and delivering a VUV laser beam to a workpiece, comprising: a discharge chamber filled with a laser active medium; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the laser active medium; a resonator including the discharge chamber for generating said VUV laser beam having a wavelength less than 200 nm; and an enclosure separating at least a portion of the beam path exiting the laser from the outer atmosphere and having a plurality of ports for flowing an inert gas of greater than 99.5% purity within said enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can reach the workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 8
Dependent Claim
53 words
The system of claim 5 , further comprising a window sealing the enclosure, wherein the window is substantially transparent at said emission wavelength less than 200 nm to allow the beam to exit the enclosure, while preventing contaminants generated within the enclosure from exiting the enclosure and contaminating surfaces outside of the enclosure.
Claim 9
Independent Claim
21 words
The system of any of claims 1 or 5 , wherein the purity of said inert gas is at least 99.9%.
Claim 10
Dependent Claim
24 words
The system of claim 7 , wherein said inert gas is selected from the group of gases including nitrogen, argon, neon, krypton and helium.
Claim 11
Dependent Claim
12 words
The system of claim 7 , wherein said inert gas comprises nitrogen.
Claim 12
Dependent Claim
12 words
The system of claim 7 , wherein said inert gas comprises argon.
Claim 13
Independent Claim
21 words
The system of any of claims 1 or 5 , wherein the purity of said inert gas is at least 99.999%.
Claim 14
Dependent Claim
24 words
The system of claim 11 , wherein said inert gas is selected from the group of gases including nitrogen, argon, neon, krypton and helium.
Claim 15
Dependent Claim
12 words
The system of claim 11 , wherein said inert gas comprises nitrogen.
Claim 16
Dependent Claim
12 words
The system of claim 11 , wherein said inert gas comprises argon.
Claim 17
Independent Claim
21 words
The system of any of claims 1 or 5 , wherein the purity of said inert gas is at least 99.99999%.
Claim 18
Dependent Claim
24 words
The system of claim 15 , wherein said inert gas is selected from the group of gases including nitrogen, argon, neon, krypton and helium.
Claim 19
Dependent Claim
12 words
The system of claim 15 , wherein said inert gas comprises nitrogen.
Claim 20
Dependent Claim
12 words
The system of claim 15 , wherein said inert gas comprises argon.
Claim 21
Independent Claim
21 words
The system of any of claims 1 or 5 , in which the beam is provided by an F 2 laser.
Claim 22
Independent Claim
21 words
The system of any of claims 1 or 5 , in which the laser beam is provided by an ArF laser.
Claim 23
Independent Claim
27 words
The system of any of claims 1 or 5 , wherein said inert gas is flowed at a flow rate of at least 150 liters per hour.
Claim 24
Independent Claim
48 words
The system of any of claims 1 or 5 , wherein said plurality of ports includes a port for evacuating said enclosure prior to flowing said inert gas therethrough, and wherein said inert gas is flowed at a flow rate of less than substantially 0.2 liters per minute.
Claim 25
Dependent Claim
20 words
The system of claim 22 , wherein said enclosure is maintained at an overpressure of less than substantially 50 mbar.
Claim 26
Independent Claim
31 words
The system of any of claims 1 or 5 , wherein said enclosure substantially comprises one or more materials selected from the group of materials consisting of stainless steel and copper.
Claim 27
Independent Claim
22 words
The system of any of claims 1 or 5 , wherein said enclosure contains no more than 0.5 ppm O 2 .
Claim 28
Independent Claim
19 words
The system of any of claims 1 or 5 , wherein said enclosure is sealably coupled to said laser.
Claim 29
Dependent Claim
139 words
An excimer or molecular fluorine laser system, comprising: a discharge chamber filled with a laser gas mixture at least including molecular fluorine and a buffer gas; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the gas mixture; a resonator including the discharge chamber for generating a laser beam; at least one intracavity line-narrowing and/or selection optic for narrowing a bandwidth of the laser beam; and an enclosure separating at least a portion of a beam path of the laser beam from the outer atmosphere and having at least one port for evacuating the enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can reach a workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 30
Dependent Claim
139 words
An excimer or molecular fluorine laser system, comprising: a discharge chamber filled with a laser gas mixture at least including molecular fluorine and a buffer gas; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the gas mixture; a resonator including the discharge chamber for generating a laser beam; at least one intracavity line-narrowing and/or selection optic for narrowing a bandwidth of the laser beam; and an enclosure separating at least a portion of a beam path of the laser beam from the outer atmosphere and having at least one port for evacuating the enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can reach a workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 31
Dependent Claim
26 words
The laser system of claim 27 , wherein the portion of the beam path that is separated from the outer atmosphere by said enclosure is intracavity.
Claim 32
Dependent Claim
67 words
The laser system of claim 28 , further comprising an additional enclosure separating at least a portion of a beam path of the laser beam exiting the resonator from the outer atmosphere and having an interior prepared substantially free of photoabsorbing species such that the energy of the beam can reach a workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 33
Dependent Claim
88 words
A beam delivery system for an excimer or molecular fluorine laser, comprising: an enclosure separating at least a portion of a beam path from the outer atmosphere, the beam path being between a discharge chamber of the laser and a resonator reflector optic; and at least one port for evacuating the enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can traverse said enclosure without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 34
Dependent Claim
88 words
A beam delivery system for an excimer or molecular fluorine laser, comprising: an enclosure separating at least a portion of a beam path from the outer atmosphere, the beam path being between a discharge chamber of the laser and a resonator reflector optic; and at least one port for evacuating the enclosure to enable the laser beam to propagate along said beam path, such that the energy of the beam can traverse said enclosure without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 35
Dependent Claim
72 words
The beam delivery system of claim 30 , further comprising an additional enclosure for separating at least a portion of a beam path of the laser beam exiting the resonator of the laser from the outer atmosphere and having an interior prepared substantially free of photoabsorbing species such that the energy of the beam can reach a workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 36
Dependent Claim
113 words
An excimer or molecular fluorine laser system, comprising: a discharge chamber filled with a laser gas mixture at least including molecular fluorine and a buffer gas; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the gas mixture; a resonator including the discharge chamber for generating a laser beam; means for separating at least a portion of a beam path of the laser beam generated by the laser system from the outer atmosphere, and for evacuating an atmosphere therein, such that the energy of the beam can traverse said beam path without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 37
Dependent Claim
113 words
An excimer or molecular fluorine laser system, comprising: a discharge chamber filled with a laser gas mixture at least including molecular fluorine and a buffer gas; a plurality of electrodes coupled with a power supply circuit for producing a pulsed discharge to energize the gas mixture; a resonator including the discharge chamber for generating a laser beam; means for separating at least a portion of a beam path of the laser beam generated by the laser system from the outer atmosphere, and for evacuating an atmosphere therein, such that the energy of the beam can traverse said beam path without substantial attenuation due to the presence of photoabsorbing species along said beam path.
Claim 38
Dependent Claim
15 words
The laser system of claim 32 , wherein said beam path separating means is intracavity.
Claim 39
Dependent Claim
70 words
The laser system of claim 33 , further comprising additional beam path separating means for separating at least a portion of a beam path of the laser beam exiting the resonator from the outer atmosphere and having an interior prepared substantially free of photoabsorbing species such that the energy of the beam can reach a workpiece without substantial attenuation due to the presence of photoabsorbing species along said beam path.
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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) | 2004-12-03 | 2005-06-04 | 2005-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-12-03 | 2009-06-04 | 2009-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-12-03 | 2013-06-04 | 2013-12-04 | $7700.00 | Window Closed / Lapsed |