Abstract: The optical device comprises a group of Fabry-Perot resonators, formed by a stack of a first and second partial reflection layer and an intermediate layer between the first and second partial reflection layer. The intermediate layer comprises a dielectric material and a group of arrays of posts embedded in the dielectric material at different positions along the intermediate layer. Each array in the group contains posts of a different non-circular shape and/or orientation in cross-section with a plane parallel to the reflection layers. As a result, Fabry-Perot resonators are formed in areas that contain different arrays, each having first and second resonance peaks at mutually different resonance frequencies for different polarization components. Light intensity sensors may be provided located below the different areas. From the intensities measured by the sensors, the intensities of different polarization components of the light can be computed over a range of wavelengths.

Abstract: A laser focusing system (330) for use in an EUV radiation source is described, the laser focusing system comprising: •—a first curved mirror (330.1) configured to receive a laser beam from a beam delivery system (320) and generate a first reflected laser beam (316); •—a second curved mirror (330.2) configured to receive the first reflected laser beam (316) and generate a second reflected laser beam (317), wherein the laser focusing system (330) is configured to focus the second reflected laser beam (317) to a target location (340) in a vessel (350) of the EUV radiation source (360).

Abstract: The optical device comprises a group of Fabry-Perot resonators, formed by a stack of a first and second partial reflection layer and an intermediate layer between the first and second partial reflection layer. The intermediate layer comprises a dielectric material and a group of arrays of posts embedded in the dielectric material at different positions along the intermediate layer. Each array in the group contains posts of a different non-circular shape and/or orientation in cross-section with a plane parallel to the reflection layers. As a result, Fabry-Perot resonators are formed in areas that contain different arrays, each having first and second resonance peaks at mutually different resonance frequencies for different polarization components. Light intensity sensors may be provided located below the different areas. From the intensities measured by the sensors, the intensities of different polarization components of the light can be computed over a range of wavelengths.

Abstract: A method of aligning a diffractive optical system, to be operated with an operating beam, comprises: aligning (558) the diffractive optical system using an alignment beam having a different wavelength range from the operating beam and using a diffractive optical element optimized (552) to diffract the alignment beam and the operating beam in the same (or a predetermined) direction. In an example, the alignment beam comprises infra-red (IR) radiation and the operating beam comprises soft X-ray (SXR) radiation. The diffractive optical element is optimized by providing it with a first periodic structure with a first pitch (pIR) and a second periodic structure with a second pitch (pSXR). After alignment, the vacuum system is pumped down (562) and in operation the SXR operating beam is generated (564) by a high harmonic generation (HHG) optical source pumped by the IR alignment beam’ optical source.

Abstract: An optical system (OS) for focusing a beam of radiation (B) on a region of interest in a metrology apparatus is described. The beam of radiation (B) comprises radiation in a soft X-ray or Extreme Ultraviolet spectral range. The optical system (OS) comprises a first stage (S1) for focusing the beam of radiation at an intermediate focus region. The optical system (OS) comprises a second stage (S2) for focusing the beam of radiation from the intermediate focus region onto the region of interest. The first and second stages each comprise a Kirkpatrick-Baez reflector combination. At least one reflector comprises an aberration-correcting reflector.

Abstract: This document describes a method of determining an overlay error during manufacturing of a multilayer semiconductor device. Manufacturing of the semiconductor device comprises forming a stack of material layers comprising depositing of at least two subsequent patterned layers of semiconductor material, the patterned layers comprising a first patterned layer having a first marker element and a second patterned layer having a second marker element. The determining of the overlay error comprises determining relative positions of the first and second marker element in relation to each other, such as to determine the overlay error between the first patterned layer and the second patterned layer. In addition an imaging step is performed on at least one of said first and second patterned layer, for determining relative positions of the respective first or second marker element and a pattern feature of a device pattern comprised by said respective first and second patterned layer.

Abstract: An optical system (OS) for focusing a beam of radiation (B) on a region of interest in a metrology apparatus is described. The beam of radiation (B) comprises radiation in a soft X-ray or Extreme Ultraviolet spectral range. The optical system (OS) comprises a first stage (S1) for focusing the beam of radiation at an intermediate focus region. The optical system (OS) comprises a second stage (S2) for focusing the beam of radiation from the intermediate focus region onto the region of interest. The first and second stages each comprise a Kirkpatrick-Baez reflector combination. At least one reflector comprises an aberration-correcting reflector.

Abstract: This document describes a method of determining an overlay error during manufacturing of a multilayer semiconductor device. Manufacturing of the semiconductor device comprises forming a stack of material layers comprising depositing of at least two subsequent patterned layers of semiconductor material, the patterned layers comprising a first patterned layer having a first marker element and a second patterned layer having a second marker element. The determining of the overlay error comprises determining relative positions of the first and second marker element in relation to each other, such as to determine the overlay error between the first patterned layer and the second patterned layer. In addition an imaging step is performed on at least one of said first and second patterned layer, for determining relative positions of the respective first or second marker element and a pattern feature of a device pattern comprised by said respective first and second patterned layer.

Abstract: A method of aligning a diffractive optical system, to be operated with an operating beam, comprises: aligning (558) the diffractive optical system using an alignment beam having a different wavelength range from the operating beam and using a diffractive optical element optimized (552) to diffract the alignment beam and the operating beam in the same (or a predetermined) direction. In an example, the alignment beam comprises infra-red (IR) radiation and the operating beam comprises soft X-ray (SXR) radiation. The diffractive optical element is optimized by providing it with a first periodic structure with a first pitch (pIR) and a second periodic structure with a second pitch (pSXR). After alignment, the vacuum system is pumped down (562) and in operation the SXR operating beam is generated (564) by a high harmonic generation (HHG) optical source pumped by the IR alignment beam’ optical source.

Abstract: The present invention relates to a bowl-shaped optical cover (110) for a light-emitting module. The optical cover (110) has an inner concave surface (112) for facing a light source, and an outer convex surface (114) for facing away from a light source. The optical cover (110) comprising: a micro lenses array structure (122) arranged on the inner surface (112) of the optical cover (110) for refracting light emitted from a light source; and a macro lens structure (124) formed between the micro lenses array structure (122) and the outer convex surface (114) of the optical cover (110). The macro lens structure(124) has a thickness (Z1), wherein the thickness (Z1) is varied along the optical cover (110) such that light is refracted from a thinner part towards a thicker part of the macro lens structure (124). Various embodiments of the present invention provide improved luminous intensity distribution and luminance uniformity.