SPECTRAL PURITY FILTER, LITHOGRAPHIC APPARATUS, METHOD FOR MANUFACTURING A SPECTRAL PURITY FILTER AND METHOD OF MANUFACTURING A DEVICE USING LITHOGRAPHIC APPARATUS

摘要

A spectral purity filter includes a substrate, a plurality of apertures through the substrate, and a plurality of walls. The walls define the plurality of apertures through the substrate. The spectral purity filter also includes a first layer formed on the substrate to reflect radiation of a first wavelength, and a second layer formed on the first layer to prevent oxidation of the first layer. The apertures are constructed and arranged to be able to transmit at least a portion of radiation of a second wavelength therethrough.