Abstract: A system and method is described for correcting aberrations caused by field curvature with a catadioptric objective. In one example, a catadioptric optical system includes a first catadioptric element and a second catadioptric element. The first catadioptric element includes a first surface positioned to reflect a beam and a second surface positioned to focus the beam reflected by the first surface. The second catadioptric element is configured to receive the beam reflected by the second surface of the first catadioptric element. The second catadioptric element includes a third surface positioned to reflect the beam, and a fourth reflective surface positioned to focus the beam reflected by the third reflective surface. A curvature of the third or fourth surfaces of the second catadioptric element is chosen to apply a positive contribution to a field curvature associated with the first catadioptric element.

Abstract: An interferometric lithography system produces a pattern having a sharp field edge and minimal optical path length difference. Light passes through a beamsplitter into an input prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the input prism toward a substrate prism. The substrate prism is symmetric to the input prism such that the incidence angle at an image plane is approximately equal to the beamsplitter diffraction angle. Alternatively, light passes through a beamsplitter into a prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the prism toward an output surface of the prism, such that the incidence angle at the output surface is approximately equal to the beamsplitter diffraction angle. A plurality of these interferometers can be stacked, each being optimized for a given pitch, such that the stack provides a variable pitch interferometry system.

Abstract: Disclosed are systems and methods for time differential reticle inspection. Contamination is detected by, for example, determining a difference between a first signature of at least a portion of a reticle and a second signature, produced subsequent to the first signature, of the portion of the reticle.

Abstract: An inspection apparatus includes an illumination system that receives a first beam and produces second and third beams from the first beam and a catadioptric objective that directs the second beam to reflect from a wafer. A first sensor detects a first image created by the reflected second beam. A refractive objective directs the third beam to reflect from the wafer, and a second sensor detects a second image created by the reflected third beam. The first and second images can be used for CD measurements. The second beam can have a spectral range from about 200 nm to about 425 nm, and the third beam can have a spectral range from about 425 nm to about 850 nm. A third sensor may be provide that detects a third image created by the third beam reflected from the wafer. The third image can be used for OV measurements.

Abstract: Disclosed are apparatuses, methods, and lithographic systems for holographic mask inspection. A holographic mask inspection system (300, 600, 700) includes an illumination source (330), a spatial filter (350), and an image sensor (380). The illumination source being configured to illuminate a radiation beam (331) onto a target portion of a mask (310). The spatial filter (350) being arranged in a Fourier transform pupil plane of an optical system (390, 610, 710), where the spatial filter receives at least a portion of a reflected radiation beam (311) from the target portion of the mask. The optical system being arranged to combine (360, 660, 740) the portion of the reflected radiation beam (311) with a reference radiation beam (361, 331) to generate a combined radiation beam. Further, the image sensor (380) being configured to capture holographic image of the combined radiation beam. The image may contain one or more mask defects.

Abstract: Disclosed are systems and methods for time differential reticle inspection. Contamination is detected by, for example, determining a difference between a first signature of at least a portion of a reticle and a second signature, produced subsequent to the first signature, of the portion of the reticle.

Abstract: A method and systems for reticle inspection. The method includes coherently illuminating surfaces of an inspection reticle and a reference reticle, applying a Fourier transform to scattered light from the illuminated surfaces, shifting the phase of the transformed light from the reference reticle such that a phase difference between the transformed light from the inspection reticle and the transformed light from the reference reticle is 180 degrees, combining the transformed light as an image subtraction, applying an inverse Fourier transform to the combined light, and detecting the combined light at a detector. An optical path length difference between two optical paths from the illumination source to the detector is less than a coherence length of the illumination source. The image detected by the detector represents a difference in amplitude and phase distributions of the reticles allowing foreign particles, defects, or the like, to be easily distinguished.

Abstract: Disclosed are systems and methods for object inspection, in particular for inspection of reticles used in a lithography process. The method includes interferometrically combining a reference radiation beam with a probe radiation beam, and storing their complex field images. The complex field image of one object is then compared with that of a reference object to determine the differences. The systems and methods have particular utility in the inspection of a reticle for defects.

Abstract: In a scatterometry apparatus having an illumination aperture stop, a field stop is provided at an intermediate image to control a spot size on a substrate. The field stop may be apodized, e.g., having a transmissivity in the form of a trapezium or a Gaussian shape.

Abstract: A catadioptric optical system operates in a wide spectral range. In an embodiment, the catadioptric optical system includes a first reflective surface positioned and configured to reflect radiation; a second reflective surface positioned and configured to reflect radiation reflected from the first reflective surface as a collimated beam, the second reflective surface having an aperture to allow transmission of radiation through the second reflective surface; and a channel structure extending from the aperture toward the first reflective surface and having an outlet, between the first reflective surface and the second reflective surface, to supply radiation to the first reflective surface.

Abstract: A method and systems for reticle inspection. The method includes coherently illuminating surfaces of an inspection reticle and a reference reticle, applying a Fourier transform to scattered light from the illuminated surfaces, shifting the phase of the transformed light from the reference reticle such that a phase difference between the transformed light from the inspection reticle and the transformed light from the reference reticle is 180 degrees, combining the transformed light as an image subtraction, applying an inverse Fourier transform to the combined light, and detecting the combined light at a detector. An optical path length difference between two optical paths from the illumination source to the detector is less than a coherence length of the illumination source. The image detected by the detector represents a difference in amplitude and phase distributions of the reticles allowing foreign particles, defects, or the like, to be easily distinguished.

Abstract: Disclosed are apparatuses, methods, and lithographic systems for EUV mask inspection. An EUV mask inspection system can include an EUV illumination source, an optical system, and an image sensor. The EUV illumination source can be a standalone illumination system or integrated into the lithographic system, where the EUV illumination source can be configured to illuminate an EUV radiation beam onto a target portion of a mask. The optical system can be configured to receive at least a portion of a reflected EUV radiation beam from the target portion of the mask. Further, the image sensor can be configured to detect an aerial image corresponding to the portion of the reflected EUV radiation beam. The EUV mask inspection system can also include a data analysis device configured to analyze the aerial image for mask defects.

Abstract: A catadioptric system is provided comprising a correcting plate and an optical system. The correcting plate is configured to condition electromagnetic radiation to correct at least one aberration. The optical system is configured to reflect a first portion of the conditioned electromagnetic radiation, to refract a second portion of the conditioned electromagnetic radiation, and to focus the reflected first portion of the conditioned electromagnetic radiation onto a target portion of a substrate. The first portion of the electromagnetic radiation is not refracted by an optical element, allowing the catadioptric optical system to operate in a broad spectral range.

Abstract: A catadioptric optical system having a high numerical aperture operates in a wide spectral range. The catadioptric optical system includes a correcting plate, a first reflective surface and a second reflective surface. The correcting plate conditions electromagnetic radiation to correct at least one aberration. The first reflective surface is positioned to reflect the electromagnetic radiation conditioned by the correcting plate. The second reflective surface is positioned to focus the electromagnetic radiation reflected by the first reflective surface onto a target portion of a substrate. The electromagnetic radiation reflected by the first reflective surface and focused by the second reflective surface is not refracted by a refractive element, thereby enabling the catadioptric optical system to operate in a broad spectral range.

Abstract: An optical integrator having a first surface and a second surface that is used in a lithographic apparatus to modify light. The first surface is reflective, defines a volume, and is configured to be disposed in an optical illumination system along an optical axis, to surround the optical axis, and to reflect a light along a path incident upon the first surface. The second surface is disposed in the volume and has a first section of the second surface that is semi-reflective and is configured to reflect a first portion of a light along a path incident upon the first section of the second surface and to transmit a second portion of the light along the path incident upon the first section of the second surface. The second surface increases the number of reflections of the light to increase the uniformity of the intensity distribution of the light.

Abstract: In a scatterometry apparatus having an illumination aperture stop, a field stop is provided at an intermediate image to control a spot size on a substrate. The field stop may be apodized, e.g., having a transmissivity in the form of a trapezium or a Gaussian shape.

Abstract: In a scatterometry apparatus having an illumination aperture stop, a field stop is provided at an intermediate image to control the spot size on the substrate. The field stop may be apodized, e.g. having a transmissivity in the form of a trapezium or a Gaussian shape.

Abstract: A coherence remover is provided. In an embodiment the coherence remover includes a first mirror and a second mirror coupled to the first mirror. The coherence remover is configured to receive an input beam. Each of the first and second mirrors is configured to reflect a respective portion of the input beam to produce respective one or more intermediate beams. The intermediate beams collectively form an output beam that has a reduced coherence compared to the input beam.

Abstract: A catadioptric optical system having a high numerical aperture operates in a wide spectral range. The catadioptric optical system includes a correcting plate, a first reflective surface and a second reflective surface. The correcting plate conditions electromagnetic radiation to correct at least one aberration. The first reflective surface is positioned to reflect the electromagnetic radiation conditioned by the correcting plate. The second reflective surface is positioned to focus the electromagnetic radiation reflected by the first reflective surface onto a target portion of a substrate. The electromagnetic radiation reflected by the first reflective surface and focused by the second reflective surface is not refracted by a refractive element, thereby enabling the catadioptric optical system to operate in a broad spectral range.

Abstract: In a scatterometry apparatus having an illumination aperture stop, a field stop is provided at an intermediate image to control the spot size on the substrate. The field stop may be apodized, e.g. having a transmissivity in the form of a trapezium or a Gaussian shape.