An inspection system, a lithography apparatus, and an inspection method are provided. The inspection system includes an illumination system, a detection system, and processing circuitry. The illumination system generates a broadband beam and illuminates surface of an object with the broadband illumination beam. The broadband beam has a continuous spectral range. The detection system receives radiation scattered at the surface and by a structure near the surface. The detection system generates a detection signal based on an optical response to the broadband illumination beam. The processing circuitry analyzes the detection signal. The processing circuitry distinguishes between a spurious signal and a signal corresponding to a defect on the surface based on the analyzing The spurious signal is diminished for at least a portion of the continuous spectral range.

A mask for Poisson spot suppression includes a plurality of petals equally spaced in a circular pattern, the petals comprising a gray scale lithography substrate, the substrate having an opaque center portion and a gradient of increasing transparency extending toward a perimeter of the circular pattern, the gradient effected by a gray scale lithography process.

A scatterometer is used in a dark-field imaging mode to measure asymmetry-related parameters such as overlay. Measurements of small grating targets are made using identical optical paths, with the target in two orientations to obtain separate measurements of +1 and −1 diffraction orders. In this way, intensity scaling differences (tool asymmetry) are avoided. However, additive intensity defects due to stray radiation (ghosts) in the optical system cannot be avoided. Additive intensity issues strongly depend on the ratio between 0th and 1st order diffraction and are therefore strongly substrate (process) dependent. Calibration measurements are made on a few representative target gratings having biases. The calibration measurements are made, using not only different substrate rotations but also complementary apertures. Corrections are calculated and applied to correct asymmetry, to reduce error caused by stray radiation.

An optical system delivers illuminating radiation and collects radiation after interaction with a target structure on a substrate. A measurement intensity profile is used to calculate a measurement of the property of the structure. The optical system may include a solid immersion lens. In a method, the optical system is controlled to obtain a first intensity profile using a first illumination profile and a second intensity profile using a second illumination profile. The profiles are used to derive a correction for mitigating the effect of, e.g., ghost reflections. Using, e.g., half-moon illumination profiles in different orientations, the method can measure ghost reflections even where a solid immersion lens would cause total internal reflection. The optical system may include a contaminant detection system to control a movement based on received scattered detection radiation. The optical system may include an optical component having a dielectric coating to enhance evanescent wave interaction.

An apparatus comprises a low EUV reflectivity (LEUVR) mask. The LEUVR mask includes a low thermal expansion material (LTEM) layer; a reflective multilayer (ML) over the LTEM layer; and a patterned absorption layer over the reflective ML. The reflective ML has less than 2% EUV reflectivity.

When a reticle is first used, the reticle is loaded in a projection exposure device and measured by either oblique measurement and random measurement, thereby avoiding the fear of uneven sampling and determining the reticle transmittance of the entire reticle as the parent population, without increasing the sampling count. The same effect can be obtained by making the measurement spot size, which is fixed in general, variable and by changing the angle of incidence in relation to the measurement spot size.

A mask (M) for EUV lithography includes: a substrate (7), a first surface region (A.sub.1) formed by a surface (8a) of a multilayer coating (8) embodied to reflect EUV radiation (27), said surface (8a) facing away from the substrate (7), and a second surface region (A.sub.2) formed by a surface (18a) of a further coating (18) embodied to reflect DUV radiation (28) and to suppress the reflection of EUV radiation (27), said surface (18a) facing away from the substrate (7). The further coating is a multilayer coating (18). Also disclosed are an EUV lithography apparatus that includes such a mask (M) and a method for determining a contrast proportion caused by DUV radiation when imaging a mask (M) onto a light-sensitive layer.

An illumination system of a microlithographic projection exposure apparatus includes a spatial light modulator which varies an intensity distribution in a pupil surface. The modulator includes an array of mirrors that reflect impinging projection light into directions that depend on control signals applied to the mirrors. A prism, which directs the projection light towards the spatial light modulator, has a double pass surface on which the projection light impinges twice, namely a first time when leaving the prism and before it is reflected by the mirrors, and a second time when entering the prism and after it has been reflected by the mirrors. A pupil perturbation suppressing mechanism is provided that reduces reflections of projection light when it impinges the first time on the double pass surface, and/or prevents that light portions being a result of such reflections contribute to the intensity distribution in the pupil surface.

Disclosed herein is a computer-implemented method of image simulation for a device manufacturing process, the method comprising: identifying regions of uniform optical properties from a portion or an entirety of a substrate or a patterning device, wherein optical properties are uniform within each of the regions; obtaining an image for each of the regions, wherein the image is one that would be formed from the substrate if the entirety of the substrate or the patterning device has the same uniform optical properties as that region; forming a stitched image by stitching the image for each of the regions according to locations of the regions in the portion or the entirety of the substrate of the patterning device; forming an adjusted image by applying adjustment to the stitched image for at least partially correcting for or at least partially imitating an effect of finite sizes of the regions.

The present disclosure relates to an extreme ultraviolet lithography, EUVL, device comprising: a reticle comprising a lithographic pattern to be imaged on a target wafer; a light-transmissive pellicle membrane mounted in front of, and parallel to, the reticle, wherein the pellicle membrane scatters transmitted light along a scattering axis; and an extreme ultraviolet, EUV, illumination system configured to illuminate the reticle through the pellicle membrane, wherein an illumination distribution provided by the EUV illumination system is asymmetric as seen in a source-pupil plane of the EUV illumination system; wherein light reflected by the reticle and then transmitted through the pellicle membrane comprises a non-scattered fraction and a scattered fraction formed by light scattered by the pellicle membrane; the EUVL device further comprising: an imaging system having an acceptance cone configured to capture a portion of the light reflected by the reticle and then transmitted through the pellicle membrane.