Abstract: An optical inspection apparatus, including: an optical metrology tool configured to measure structures, the optical metrology tool including: an electromagnetic (EM) radiation source configured to direct a beam of EM radiation along an EM radiation path; and an adaptive optical system disposed in a portion of the EM radiation path and configured to adjust a shape of a wave front of the beam of EM radiation, the adaptive optical system including: a first aspherical optical element; a second aspherical optical element adjacent the first aspherical optical element; and an actuator configured to cause relative movement between the first optical element and the second optical element in a direction different from a beam axis of the portion of the EM radiation path.

Abstract: A beam homogenizer for homogenizing a beam of radiation and an illumination system and metrology apparatus comprising such a beam homogenizer as provided. The beam homogenizer comprises a filter system having a controllable radial absorption profile and configured to output a filtered beam and an optical mixing element configured to homogenize the filtered beam. The filter system may be configured to homogenize the angular beam profile radially and said optical mixing element may be configured to homogenize the angular beam profile azimuthally.

Abstract: Disclosed is an illumination system for a metrology apparatus and a metrology apparatus comprising such an illumination system. The illumination system comprises an illumination source; and a linear variable filter arrangement configured to filter a radiation beam from said illumination source and comprising one or more linear variable filters. The illumination system is operable to enable selective control of a wavelength characteristic of the radiation beam subsequent to it being filtered by the linear variable filter arrangement.

Abstract: Disclosed are an optical system for conditioning a beam of radiation, and an illumination system and metrology apparatus comprising such an optical system. The optical system comprises one or more optical mixing elements in an optical system. The optical system defines at least a first optical mixing stage, at least a second optical mixing stage, and at least one transformation stage, configured such that radiation entering the second optical mixing stage includes a transformed version of radiation exiting the first optical mixing stage. The first and second optical mixing stages can be provided using separate optical mixing elements, or by multiple passes through the same optical mixing element. The transformation stage can be a Fourier transformation stage. Both spatial distribution and angular distribution of illumination can be homogenized as desired.

Abstract: Devices and methods for processing a radiation beam with coherence are disclosed. In one arrangement, an optical system receives a radiation beam with coherence. The radiation beam comprises components distributed over one or more radiation beam spatial modes. A waveguide supports a plurality of waveguide spatial modes. The optical system directs a plurality of the components of the radiation beam belonging to a common radiation beam spatial mode and having different frequencies onto the waveguide in such a way that each of the plurality of components couples to a different set of the waveguide spatial modes, each set comprising one or more of the waveguide spatial modes.

Abstract: An optical inspection apparatus, including: an optical metrology tool configured to measure structures, the optical metrology tool including: an electromagnetic (EM) radiation source configured to direct a beam of EM radiation along an EM radiation path; and an adaptive optical system disposed in a portion of the EM radiation path and configured to adjust a shape of a wave front of the beam of EM radiation, the adaptive optical system including: a first aspherical optical element; a second aspherical optical element adjacent the first aspherical optical element; and an actuator configured to cause relative movement between the first optical element and the second optical element in a direction different from a beam axis of the portion of the EM radiation path.

Abstract: Devices and methods for processing a radiation beam with coherence are disclosed. In one arrangement, an optical system receives a radiation beam with coherence. The radiation beam comprises components distributed over one or more radiation beam spatial modes. A waveguide supports a plurality of waveguide spatial modes. The optical system directs a plurality of the components of the radiation beam belonging to a common radiation beam spatial mode and having different frequencies onto the waveguide in such a way that each of the plurality of components couples to a different set of the waveguide spatial modes, each set comprising one or more of the waveguide spatial modes.

Abstract: Disclosed are an optical system for conditioning a beam of radiation, and an illumination system and metrology apparatus comprising such an optical system. The optical system comprises one or more optical mixing elements in an optical system. The optical system defines at least a first optical mixing stage, at least a second optical mixing stage, and at least one transformation stage, configured such that radiation entering the second optical mixing stage includes a transformed version of radiation exiting the first optical mixing stage. The first and second optical mixing stages can be provided using separate optical mixing elements, or by multiple passes through the same optical mixing element. The transformation stage can be a Fourier transformation stage. Both spatial distribution and angular distribution of illumination can be homogenized as desired.

Abstract: Disclosed is an illumination system for a metrology apparatus and a metrology apparatus comprising such an illumination system. The illumination system comprises an illumination source; and a linear variable filter arrangement configured to filter a radiation beam from said illumination source and comprising one or more linear variable filters. The illumination system is operable to enable selective control of a wavelength characteristic of the radiation beam subsequent to it being filtered by the linear variable filter arrangement.

Abstract: A beam homogenizer for homogenizing a beam of radiation and an illumination system and metrology apparatus comprising such a beam homogenizer as provided. The beam homogenizer comprises a filter system having a controllable radial absorption profile and configured to output a filtered beam and an optical mixing element configured to homogenize the filtered beam. The filter system may be configured to homogenize the angular beam profile radially and said optical mixing element may be configured to homogenize the angular beam profile azimuthally.

Abstract: A laser driven light source comprises laser and focusing optics. These produce a beam of radiation focused on a plasma forming zone within a container containing a gas (e.g., Xe). Collection optics collects photons emitted by a plasma maintained by the laser radiation to form a beam of output radiation. Plasma has an elongate form (L>d) and collecting optics is configured to collect photons emerging in the longitudinal direction from the plasma. The brightness of the plasma is increased compared with sources which collect radiation emerging transversely from the plasma. A metrology apparatus using the light source can achieve greater accuracy and/or throughput as a result of the increased brightness. Back reflectors may be provided. Microwave radiation may be used instead of laser radiation to form the plasma.

Abstract: A laser driven light source comprises laser and focusing optics. These produce a beam of radiation focused on a plasma forming zone within a container containing a gas (e.g., Xe). Collection optics collects photons emitted by a plasma maintained by the laser radiation to form a beam of output radiation. Plasma has an elongate form (L>d) and collecting optics is configured to collect photons emerging in the longitudinal direction from the plasma. The brightness of the plasma is increased compared with sources which collect radiation emerging transversely from the plasma. A metrology apparatus using the light source can achieve greater accuracy and/or throughput as a result of the increased brightness. Back reflectors may be provided. Microwave radiation may be used instead of laser radiation to form the plasma.

Abstract: A laser driven light source comprises laser and focusing optics. These produce a beam of radiation focused on a plasma forming zone within a container containing a gas (e.g., Xe). Collection optics collects photons emitted by a plasma maintained by the laser radiation to form a beam of output radiation. Plasma has an elongate form (L>d) and collecting optics is configured to collect photons emerging in the longitudinal direction from the plasma. The brightness of the plasma is increased compared with sources which collect radiation emerging transversely from the plasma. A metrology apparatus using the light source can achieve greater accuracy and/or throughput as a result of the increased brightness. Back reflectors may be provided. Microwave radiation may be used instead of laser radiation to form the plasma.

Abstract: A laser driven light source comprises laser and focusing optics. These produce a beam of radiation focused on a plasma forming zone within a container containing a gas (e.g., Xe). Collection optics collects photons emitted by a plasma maintained by the laser radiation to form a beam of output radiation. Plasma has an elongate form (L>d) and collecting optics is configured to collect photons emerging in the longitudinal direction from the plasma. The brightness of the plasma is increased compared with sources which collect radiation emerging transversely from the plasma. A metrology apparatus using the light source can achieve greater accuracy and/or throughput as a result of the increased brightness. Back reflectors may be provided. Microwave radiation may be used instead of laser radiation to form the plasma.

Abstract: A scatterometer configured to derive a property of a substrate, includes an optical arrangement that produces a beam of radiation. An objective lens is arranged to focus the beam of radiation onto a target on the substrate. The optical arrangement is arranged to change the divergence of the beam incident on the objective lens, thereby changing spherical aberration caused by the objective lens on the beam focused on the target. A detection arrangement is arranged to detect the beam of radiation after reflection or scattering from the substrate.

Abstract: An inspection apparatus configured to measure a property of a substrate includes an illumination source, a beam splitter, a first polarizer positioned between the illumination source and the beam splitter, an objective lens and an optical device that alters a polarization state of radiation traveling through it positioned between the beam splitter and the substrate and a second polarizer positioned between the beam splitter and a detector. An axis of the second polarizer is rotated with respect to an axis of the first polarizer. Radiation polarized by the first polarizer that reflects off any optical elements between the beam splitter and the optical device is prevented from entering the detector by the second polarizer. Only radiation that passes twice through the optical device has its polarization direction rotated so that it passes through the second polarizer and enters the detector.

Abstract: A scatterometer configured to derive a property of a substrate, includes an optical arrangement that produces a beam of radiation. An objective lens is arranged to focus the beam of radiation onto a target on the substrate. The optical arrangement is arranged to change the divergence of the beam incident on the objective lens, thereby changing spherical aberration caused by the objective lens on the beam focused on the target. A detection arrangement is arranged to detect the beam of radiation after reflection or scattering from the substrate.

Abstract: An optical scanning device (3) for scanning a multiple of types of optical recording media. The optical scanning device is provided with a filtering means (301) that is arranged and configured such that when scanning an optical recording medium (15) having plurality of information layers (L0, L1) radiation reflected by another information layer than the information layer being scanned is not reaching the radiation detector (38), while the filtering means is substantially not affecting the radiation towards the radiation detector when another type of recording media is scanned. Improved data signal reproduction and tracking servo signals are obtained.