Ion-assisted deposition techniques for the planarization of topological defects
AssigneeThe Regents of the University of California
InventorsPaul B. Mirkarimi, Eberhard A. Spiller, Daniel G. Stearns
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Abstract
An ion-assisted deposition technique to provide planarization of topological defects, e.g., to mitigate the effects of small particle contaminants on reticles for extreme ultraviolet (EUV) lithography. Reticles for EUV lithography will be fabricated by depositing high EUV reflectance Mo/Si multilayer films on superpolished substrates and topological substrate defects can nucleate unacceptable (“critical”) defects in the reflective Mo/Si coatings. A secondary ion source is used to etch the Si layers in between etch steps to produce topological defects with heights that are harmless to the lithographic process.
Claims20
A method for the mitigation of topological defects of an optical material, wherein said optical material comprises at least one layer of amorphous material, the method comprising planarizing with an ion beam only said at least one layer of amorphous material.
An EUV reticle, comprising a bi-layer of optical material on a substrate, wherein said at least one layer of amorphous material forms one layer of said bi-layer and has an index of refraction that is less than a material that forms another layer of said bi-layer, wherein only said at least one layer of amorphous material has been planarized with an ion beam.
Dependencies are inferred from the claim text.