Very narrow band, two chamber, high rep-rate gas discharge laser system

• US 7,567,607 B2
• Filed: 02/01/2006
• Issued: 07/28/2009
• Est. Priority Date: 12/10/1999
• Status: Expired due to Fees

• Current Assignee: Cymer Incorporated (ASML Holding NV)
• Original Assignee: Cymer Incorporated (ASML Holding NV)
• Inventors: Anderson, Stuart L., Myers, David W., Hulburd, William G., Smith, Scot T., Oicles, Jeffrey, Onkels, Eckehard D., Sandstrom, Richard L., Das, Palash P., Brown, Daniel J. W., Fomenkov, Igor V., Ershov, Alexander I., Partlo, William N., Ujazdowski, Richard C., Ness, Richard M., Besaucele, Herve A., Knowles, David S.
• Primary Examiner(s): Harvey; Minsun
• Assistant Examiner(s): FORDE, DELMA ROSA
• Application Number:
  US11/346,519
• Publication Number:
  US 20060126697A1
• Time in Patent Office: 1,273 Days
• Field of Search: 372 55- 58
• US Class Current: 372/55
• CPC Class Codes: G01J 1/4257 applied to monitoring the characteristics of a beam, e.g. laser beam, headlamp beam monitoring arrangements for lasers in general H01S3/0014
• CPC Class Codes: G03F 7/70025 by lasers
• CPC Class Codes: G03F 7/70041 by pulsed sources, e.g. multiplexing, pulse duration, interval control or intensity control
• CPC Class Codes: G03F 7/70333 Focus drilling, i.e. increase in depth of focus for exposure by modulating focus during exposure [FLEX]
• CPC Class Codes: G03F 7/70483 Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
• CPC Class Codes: G03F 7/70575 Wavelength control, e.g. control of bandwidth, multiple wavelength, selection of wavelength or matching of optical components to wavelength
• CPC Class Codes: G03F 7/70933 Purge, e.g. exchanging fluid or gas to remove pollutants
• CPC Class Codes: H01S 3/005 Optical devices external to the laser cavity, specially adapted for lasers, e.g. for homogenisation of the beam or for manipulating laser pulses, e.g. pulse shaping shaping laser beam for working metal or other materials B23K26/06; optical elements, systems or apparatus in general G02B
• CPC Class Codes: H01S 3/0057 Temporal shaping, e.g. pulse compression, frequency chirping soliton generation and propagation G02F1/3513, H01S3/063 and H01S3/108
• CPC Class Codes: H01S 3/02 Constructional details housings or packages of fibre lasers H01S3/06704
• CPC Class Codes: H01S 3/03 of gas laser discharge tubes
• CPC Class Codes: H01S 3/0346 Protection of windows or mirrors against deleterious effects cooling arrangements H01S3/0401
• CPC Class Codes: H01S 3/036 Means for obtaining or maintaining the desired gas pressure within the tube, e.g. by gettering, replenishing; Means for circulating the gas, e.g. for equalising the pressure within the tube H01S3/031 takes precedence
• CPC Class Codes: H01S 3/038 Electrodes, e.g. special shape, configuration or composition
• CPC Class Codes: H01S 3/0385 Shape
• CPC Class Codes: H01S 3/0387 Helical shape
• CPC Class Codes: H01S 3/0404 Air- or gas cooling, e.g. by dry nitrogen
• CPC Class Codes: H01S 3/041 for gas lasers H01S3/0401 takes precedence
• CPC Class Codes: H01S 3/08004 incorporating a dispersive element, e.g. a prism for wavelength selection H01S3/0811, H01S3/08022 take precedence
• CPC Class Codes: H01S 3/08009 using a diffraction grating
• CPC Class Codes: H01S 3/08036 : using intracavity dispersive, polarising or birefringent elements
• CPC Class Codes: H01S 3/0943 : of a gas laser
• CPC Class Codes: H01S 3/097 : by gas discharge of a gas laser
• CPC Class Codes: H01S 3/09702 : Details of the driver electronics and electric discharge circuits
• CPC Class Codes: H01S 3/09705 : with particular means for stabilising the discharge
• CPC Class Codes: H01S 3/0971 : transversely excited H01S3/0975 takes precedence
• CPC Class Codes: H01S 3/0975 : using inductive or capacitive excitation
• CPC Class Codes: H01S 3/104 : in gas lasers
• CPC Class Codes: H01S 3/105 : by controlling the mutual position or the reflecting properties of the reflectors of the cavity , e.g. by controlling the cavity lengthH01S3/10076, H01S3/13 take precedence
• CPC Class Codes: H01S 3/1055 : one of the reflectors being constituted by a diffraction grating
• CPC Class Codes: H01S 3/1305 : Feedback control systems
• CPC Class Codes: H01S 3/134 : in gas lasers
• CPC Class Codes: H01S 3/137 : for stabilising of frequency
• CPC Class Codes: H01S 3/139 : by controlling the mutual position or the reflecting properties of the reflectors of the cavity , e.g. by controlling the cavity length
• CPC Class Codes: H01S 3/22 : Gases
• CPC Class Codes: H01S 3/2207 : Noble gas ions, e.g. Ar+>, Kr+>
• CPC Class Codes: H01S 3/223 : the active gas being polyatomic, i.e. containing two or more atoms H01S3/227 takes precedence
• CPC Class Codes: H01S 3/225 : comprising an excimer or exciplex
• CPC Class Codes: H01S 3/2251 : ArF, i.e. argon fluoride is comprised for lasing around 193 nm
• CPC Class Codes: H01S 3/2256 : KrF, i.e. krypton fluoride is comprised for lasing around 248 nm
• CPC Class Codes: H01S 3/2258 : F2, i.e. molecular fluoride is comprised for lasing around 157 nm
• CPC Class Codes: H01S 3/2333 : Double-pass amplifiers
• CPC Class Codes: H01S 3/2366 : comprising a gas as the active medium H01S3/10092, H01S3/2383 take precedence

Abstract

An oscillator-amplifier gas discharge laser system and method is disclosed which may comprise a first laser unit which may comprise a first discharge region which may contain an excimer or molecular fluorine lasing gas medium; a first pair of electrodes defining the first discharge region containing the lasing gas medium, a line narrowing unit for narrowing a spectral bandwidth of output laser light pulse beam pulses produced in said first discharge region; a second laser unit which may comprise a second discharge chamber which may contain an excimer or molecular fluorine lasing gas medium; a second pair of electrodes defining the second discharge region containing the lasing gas medium; a pulse power system providing electrical pulses to the first pair of electrodes and to the second pair of electrodes producing gas discharges in the lasing gas medium between the respective first and second pair of electrodes, and laser parameter control mechanism modifying a selected parameter of a selected laser output light pulse beam pulse produced by said gas discharge laser system by controlling the timing of the occurrence of the gas discharge between the first pair of electrodes and the occurrence of the gas discharge between the second pair of electrodes.

Claims

1. An apparatus comprising:

a multi-chamber gas discharge laser system comprising;

a first laser unit comprising;

a first discharge region containing;

an excimer or molecular fluorine lasing gas medium;

a first pair of electrodes defining the first discharge region containing the lasing gas medium,

a line narrowing unit for narrowing a spectral bandwidth of output laser light pulse beam pulses produced in said first discharge region, comprising a grating;

a second laser unit comprising;

a second discharge chamber containing;

an excimer or molecular fluorine lasing gas medium;

a second pair of electrodes defining the second discharge region containing the lasing gas medium;

a pulse power system providing electrical pulses to the first pair of electrodes and to the second pair of electrodes producing gas discharges in the lasing gas medium between the respective first and second pair of electrodes,

and a laser parameter control mechanism modifying a selected parameter of a selected laser output light pulse beam pulse produced by said gas discharge laser system by modifying the wavefront of the laser light pulse beam, comprising;

a deformable wavelength selection optical element comprising an element of the line narrowing unit other than the grating.

3. The apparatus of claim 1, wherein the deformable optical element comprises a fast tuning mirror.

2. The apparatus of claim I further comprising:

a coherence reducing optical element