Deep ultraviolet soft x-ray projection lithography method and mask apparatus

摘要

The present invention relates to reflective masks and their use for reflecting extreme ultraviolet soft x-ray photons to enable the use of extreme ultraviolet soft x-ray radiation projection lithographic methods and systems for producing integrated circuits and forming patterns with extremely small feature dimensions. The projection lithographic method includes providing an illumination sub-system for producing and directing an extreme ultraviolet soft. x-ray radiation lambd from an extreme ultraviolet soft x-ray source; providing a mask sub-system illuminated by the extreme ultraviolet soft x-ray radiation lambd produced by the illumination sub-system and providing the mask sub-system includes providing a patterned reflective mask for forming a projected mask pattern when illuminated by radiation lambd. Providing the patterned reflective mask includes providing a Ti doped high purity SiO2 glass wafer with a patterned absorbing overlay overlaying the reflective multilayer coated Ti doped high purity SiO2 glass defect free wafer surface that has an Ra roughness =0.15 nm. The method includes providing a projection sub-system and a print media subject wafer which has a radiation sensitive wafer surface wherein the projection sub-system projects the projected mask pattern from the patterned reflective mask onto the radiation sensitive wafer surface.