Spectral purity filter, lithographic apparatus, and method for manufacturing a spectral purity filter

摘要

A method of forming a spectral purity filter having a plurality of apertures configured to transmit extreme ultraviolet radiation and suppress transmission of a second type of radiation, in which trenches are formed in a base material in a pattern corresponding to the walls to be formed between the apertures. The trenches are filled with a grid material to form walls of the grid material, and the base material is selectively removed until the grid material is exposed and forms the spaces between the walls of the grid material for the apertures.

主权项

1. A method of manufacturing a spectral purity filter comprising a plurality of apertures configured to transmit extreme ultraviolet radiation and suppress transmission of a second type of radiation, the method comprising:
providing a base material having first and second major surfaces; forming trenches in the first surface of said base material in a pattern corresponding to walls to be formed between the apertures of the spectral purity filter; filling the trenches with a grid material to form walls of the grid material; and selectively removing at least a part of the base material until the grid material is exposed and forms spaces between the walls of the grid material to form the apertures.