Abstract: Collection reflectors with multiple reflector elements defined on a curved surface are used to collect EUV optical radiation from an EUV emitting area. Each of the reflector elements can image the emitting area at or near a corresponding reflective element of a second multi-element reflector that overlaps radiation from each of the multiple reflector element of the collection reflector to illuminate a grating reticle. Systems with such a collection reflector can use fewer optical elements. In addition, grating reticles are defined on a curve substrate an include a plurality of grating phase steps so that the grating reticle provides phase curvature along two axes but with physical curvature along a single axis. Methods of producing varying duty cycle 1D patterns are also disclosed.

Abstract: Electron beam position, size, or shape can be estimated by deflecting the beam to a plurality of apertures, either continuously or step-wise. Beam portions transmitted, absorbed, or scattered can be used to assess position, size, and shape. In other examples, a beam sensing aperture and the beam are oscillated with respect to each other by moving the aperture or varying the beam deflection or both. The beam can be directed to segmented detectors such as a quad detector, and currents in the segments used to assess beam position, shape, or size. The segments can be formed from a single conductive sheet on which the segments are defined but remain attached. After the conductive sheet is secured with an insulative adhesive, portions of the conductive sheet are broken away, leaving aligned segments.