LITHOGRAPHIC APPARATUS

摘要

A radiation source for a lithographic apparatus uses a plurality of fiber lasers to ignite a fuel droplet at an ignition location to generate EUV radiation. The fiber lasers may be provided to emit parallel to an optical axis and a telescopic optical system is provided to focus the lasers at the ignition location, or the lasers may be directed towards the optical axis with a final focus lens being used to reduce beam waist. The lasers may be provided in two or more groups to allow them to be independently controlled and some of the lasers may be focused at a different location to provide a pre-pulse. Radiation from fiber lasers may also be combined using dichroic mirrors.