A method for reducing M3D effects on imaging is described. The method includes identifying points within a source plane of the photolithography system that are associated with pattern shifts resulting from diffraction of light off a photomask under an angle of incidence between an imaging beam of radiation and the mask normal, determining pattern shifts associated with the identified source plane points, and modifying the source to reduce the determined pattern shifts.

When measuring a reflectivity of an object for measurement light, initially the object and a reflectivity measurement apparatus are provided. The latter includes a measurement light source, an object holder for holding the object and a spatially resolving detector for capturing measurement light reflected by the object. A measurement light beam impinges on a section of the object within a field of view of the measurement apparatus. The reflected measurement light coming from the impinged-upon section of the object is captured. A surface area of the captured section is at most 50 μm×50 μm. The measurement is performed by the detector. Next, at least one reflectivity parameter of the object is determined on the basis of an intensity of the captured measurement light. The result is a measurement method and a metrology system operating therewith, whereby reflectivities in particular of very finely structured objects, such as lithography masks, can be measured with sufficient precision.

A method includes applying a first voltage to a source of a first transistor of a detector unit of a semiconductor detector in a test wafer and applying a second voltage to a gate of the first transistor and a drain of a second transistor of the detector unit. The first transistor is coupled to the second transistor in series, and the first voltage is higher than the second voltage. A pre-exposure reading operation is performed to the detector unit. Light of an exposure apparatus is illuminated to a gate of the second transistor after applying the first and second voltages. A post-exposure reading operation is performed to the detector unit. Data of the pre-exposure reading operation is compared with the post-exposure reading operation. An intensity of the light is adjusted based on the compared data of the pre-exposure reading operation and the post-exposure reading operation.

A metrology system may include a characterization tool configured to generate metrology data for a sample based on the interaction of an illumination beam with the sample, and may also include one or more adjustable measurement parameters to control the generation of metrology data. The metrology system may include one or more processors that may receive design data associated with a plurality of regions of interest for measurement, select individualized measurement parameters of the characterization tool for the plurality of regions of interest, and direct the characterization tool to characterize the plurality of regions of interest based on the individualized measurement parameters.

Apparatus, methods and are disclosed for measuring refractive index of an absorber material used in EUV phase shift masks. The method and apparatus utilize a reference measurement and as series of reflectance measurements at a range of EUV wavelengths and thickness values for the absorber material to determine the refractive index of the absorber material.

Methods and apparatus for determining an intensity profile of a radiation beam. The method comprises providing a diffraction structure, causing a relative movement of the diffraction structure relative to the radiation beam from a first position, wherein the radiation beam does not irradiate the diffraction structure to a second position, wherein the radiation beam irradiates the diffraction structure, measuring, with a radiation detector, diffracted radiation signals produced from a diffraction of the radiation beam by the diffraction structure as the diffraction structure transitions from the first position to the second position or vice versa, and determining an intensity profile of the radiation beam based on the measured diffracted radiation signals.

An apparatus for receiving input radiation and broadening a frequency range of the input radiation to provide broadband output radiation. The apparatus includes a chamber, a fiber, a gas generating apparatus, and a radical generating apparatus. The fiber includes a hollow core configured to guide radiation propagating through the fiber, the hollow core in fluid communication with the chamber. The gas generating apparatus is configured to provide a gas within the chamber. The radical generating apparatus is configured to provide free radicals within the chamber to reduce contaminants in the gas. The apparatus may be included in a radiation source.

An apparatus for receiving input radiation and broadening a frequency range of the input radiation to provide broadband output radiation. The apparatus includes a chamber, a fiber, a gas generating apparatus, and a radical generating apparatus. The fiber includes a hollow core configured to guide radiation propagating through the fiber, the hollow core in fluid communication with the chamber. The gas generating apparatus is configured to provide a gas within the chamber. The radical generating apparatus is configured to provide free radicals within the chamber to reduce contaminants in the gas. The apparatus may be included in a radiation source.

A measurement illumination optical unit guides illumination light into an object field of a projection exposure apparatus for EUV lithography. The illumination optical unit has a field facet mirror with a plurality of field facets and a pupil facet mirror with a plurality of pupil facets. The latter serve for overlaid imaging in the object field of field facet images of the field facets. A field facet imaging channel of the illumination light is guided via any one field facet and any one pupil facet. A field stop specifies a field boundary of an illumination field in the object plane. The illumination field has a greater extent along one field dimension than any one of the field facet images. At least some of the field facets include tilt actuators which help guide the illumination light into the illumination field via various field facets and one and the same pupil facet.

In corner sections of first to fourth quadrants whose origin point is a center of an upper surface of a stage, three each of two-dimensional heads are provided. The three each of two-dimensional heads include one first head and two second heads. The stage is driven, while measuring a position of the stage using three first heads that face a two-dimensional grating of a scale plate provided above the stage from the four first heads, and during the driving, difference data of measurement values of the two second heads with respect to the first head in a measurement direction are taken in for head groups to which the three first heads belong, respectively, and using the difference data, grid errors are calibrated.