Abstract: An extreme ultraviolet light generation apparatus includes: a chamber in which plasma is generated from a target substance at a condensation position of a laser beam; a condenser mirror configured to condense extreme ultraviolet light generated by the plasma; and a magnetic field generation unit configured to generate a magnetic field that converges a charged particle generated by the plasma toward a wall of the chamber, the condenser mirror includes a substrate, a reflective layer, and a protective layer provided on the reflective layer, the protective layer has layer thickness distribution in which a layer thickness of the protective layer from a reflective layer surface changes, and the layer thickness of the protective layer is maximum at a position on a line (CL) on which a plane passing through a magnetic field axis of the magnetic field generation unit and a central axis (CA) of the condenser mirror intersects the reflective layer surface (62F).

Abstract: An extreme ultraviolet light generation apparatus includes: a chamber in which plasma is generated from a target substance at a condensation position of a laser beam; a condenser mirror configured to condense extreme ultraviolet light generated by the plasma; and a magnetic field generation unit configured to generate a magnetic field that converges a charged particle generated by the plasma toward a wall of the chamber, the condenser mirror includes a substrate, a reflective layer, and a protective layer provided on the reflective layer, the protective layer has layer thickness distribution in which a layer thickness of the protective layer from a reflective layer surface changes, and the layer thickness of the protective layer is maximum at a position on a line (CL) on which a plane passing through a magnetic field axis of the magnetic field generation unit and a central axis (CA) of the condenser mirror intersects the reflective layer surface (62F).

Abstract: An extreme ultraviolet light generating system may include: a chamber; a target feeding unit configured to feed a target into the chamber; a drive laser unit configured to irradiate the target with a drive pulsed laser light beam to generate a plasma to thereby generate extreme ultraviolet light; a probe laser unit configured to irradiate the plasma with a probe pulsed laser light beam to thereby generate Thomson scattered light; a spectrometer configured to measure a spectrum waveform of an ionic term in the Thomson scattered light; and a wavelength filter disposed upstream of the spectrometer, and configured to suppress light with a predetermined wavelength from entering the spectrometer. The light with the predetermined wavelength may be part of light containing the Thomson scattered light, and the predetermined wavelength may be substantially same as a wavelength of the probe pulsed laser light beam.