Radiation system, radiation collector, radiation beam conditioning system, spectral purity filter for a radiation system and method of forming a spectral purity filter

Abstract

A radiation system is configured tp generate a radiation beam. The radiation system comprising a chamber that includes a radiation source configured to generate radiation, a radiation beam emission aperture, and a radiation collector configured to collect radiation generated by the source, and to transmit the collected radiation to the radiation beam emission aperture. The radiation collector includes a spectral purity filter configured to enhance a spectral purity of the radiation to be emitted via the aperture. The spectral purity filter comprising: a base substrate; a multilayer stack on the base substrate, the multilayer stack comprising a plurality of alternating layers; and a plurality of recesses in a top side of the multilayer stack, the recesses being configured to allow the radiation having the first wavelength to be reflected in the first direction and to reflect the radiation having the second wavelength in the second direction; wherein the recesses are configured such that, in cross-section, they have a symmetric profile.

Description

[0001] Cross References to Related Applications [0002] This application claims the benefit of US Provisional Application 61 / 057,704, filed May 30, 2008, which is hereby incorporated by reference in its entirety. technical field [0003] The invention relates to radiation systems, radiation collectors, radiation beam conditioning systems, spectral purity filters for radiation systems and methods for forming spectral purity filters. Background technique [0004] A lithographic apparatus is a machine that applies a desired pattern to a substrate, usually a target portion of the substrate. For example, lithographic equipment may be used in the manufacture of integrated circuits (ICs). In this case, a patterning device, alternatively referred to as a mask or reticle, may be used to generate the circuit pattern to be formed on the individual layers of the IC. The pattern can be transferred onto a target portion (eg, comprising a portion, one or more dies) on a substrate (eg, a...

AI Technical Summary

Problems solved by technology

However, spectral purity filters that have been developed may not be able to withstand high thermal loads, may be limited in size and may not provide the desired filtering

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