A COLLECTOR OPTICAL SYSTEM

摘要

A collector optical system for extreme ultraviolet (EUV) or X-ray applications, including lithography and imaging, in which radiation is collected from a radiation source (e.g. laser produced plasma or source) and directed to an image focus, comprising: one or more mirrors, the or each mirror being symmetric about an optical axis extending through the radiation source and the or each mirror having at least first and second reflective surfaces, the first and second reflective surfaces having a common focus, whereby, in use, radiation from the source undergoes successive grazing incidence reflections at said first and second reflective surfaces; and wherein the common focus is transversely offset by a predetermined distance ?r with respect to the optical axis. Also disclosed is an EUV lithography system comprising: a radiation source, for example a LPP source, the collector optical system; an optical condenser; and a reflective mask. Also disclosed is an imaging optical system for EUV or X-ray imaging, and an EUV or X-ray imaging system, comprising: the imaging optical system; and an imaging device, for example a CCD array, disposed at the image focus.